WRC_541

The Welding Research Council, Inc.

EVALUATION OF MATERIAL STRENGTH DATA FOR USE IN CONJUNCTION WITH API 530 January 2011

M. Prager1, D.A. Osage2

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Materials Property Council, PO Box 1942, New York, NY 10156 The Equity Engineering Group, Inc., 20600 Chagrin Blvd., Shaker Heights, OH 44122 WRC Bulletin 541 Evaluation of Material Strength Data for Use in Conjunction with API 530

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ISBN No. 1-58145-548-8 Library of Congress Catalog Card Number: 85-647116

Copyright © 2011 by Welding Research Council, Inc. All Rights Reserved Printed in U. S. A

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WRC Bulletin 541 Evaluation of Material Strength Data for Use in Conjunction with API 530


FOREWORD This WRC Bulletin entitled Evaluation of Material Strength Data for Use in Conjunction with API 530 is one of a series of Welding Research Council (WRC) Bulletins intended to capture in detail the technical information that supports important and widely used international codes and standards such as those of ASME and API. WRC and its Materials Properties Council (MPC) and Pressure Vessel Research Council (PVRC) have for over 50 years played instrumental roles in advancing the technology needed to assure reliability and safety of pressure vessels and structures. The data for this project were gathered and analyzed by MPC under API contract. It was logical that MPC was selected for this study of properties applicable to high-temperature tubular materials produced by modern steel making practices for petroleum refinery heaters designed to API 530. More than 50 years ago Dr. George V. Smith acting under the auspices of MPC and its forerunner, the ASTM-ASME Joint Committee on the Effects of Temperature on the Properties of Materials, collected and evaluated much of the data that was used by API to support the design curves that would appear in API 530. The Joint Committee and MPC later pioneered in development of statistically rigorous computerized techniques for analyzing and extrapolating elevated time-dependent mechanical property data. The methods developed were applied to optimize Larson-Miller Parameter (LMP) stress-rupture constants for each material as desired by API for use in API 530. Optimization of the LMP constant enhances the accuracy of property extrapolation for the purpose of life assessment as well as design. The polynomial expressions provided for the LMP parameters and all other mechanical properties in this Bulletin are intended to support computerized design and life assessment activities. For further details about tools for life assessment the reader is referred to API/ASME FFS-1. Detailed presentations of solutions to the examples in this Bulletin facilitate implementation of the methods used. The assistance of Mary Buchheim and Tom Dirham of the Equity Engineering Group in carefully documenting and checking the document is gratefully acknowledged. Martin Prager Executive Director Welding Research Council


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TABLE OF CONTENTS 1 Introduction ....................................................................................................................................7 2 Yield Strength .................................................................................................................................7 3 Ultimate Tensile Strength..............................................................................................................7 4 time-independent Allowable Stress .............................................................................................8 5 Larson-Miller Parameter ................................................................................................................8 6 time-dependent Allowable Stress ................................................................................................9 7 Rupture Exponent ..........................................................................................................................9 8 Applicable ASTM Specifications ................................................................................................10 9 Material Physical Properties .......................................................................................................10 10 Nomenclature ...............................................................................................................................10 11 Example Problems .......................................................................................................................11 11.1 Problem 1 – Calculate the minimum yield and the tensile strength at 400°F, for 2.25Cr-1Mo. .....................................................................................................................................11 11.2 Problem 2 – Determine the elastic design stress for 2.25 Cr-1Mo at 500°F. .................13 11.3 Problem 3 – Develop a plot of stress versus Larson-Miller Parameter (LMP) for 2.25Cr-1Mo. .....................................................................................................................................14 11.4 Problem 4 – Calculate the service life for 2.25Cr-1Mo at 975°F and 10 ksi stress using the minimum and average Larson-Miller Parameters. ................................................................15 11.5 Problem 5 – Determine the service life for 2.25Cr-1Mo at 515°C and 100 MPa using the minimum and average Larson-Miller Parameters. ......................................................................16 11.6 Problem 6 – Determine the Rupture Exponent, n , for 2.25 Cr-1Mo as a function of temperature. ....................................................................................................................................17 11.7 Problem 7 – Develop a plot of stress verse service life for 2.25 Cr-1Mo at temperatures of 1000°F and 1025°F based on the minimum Larson-Miller constant. ............19 11.8 Problem 8 – Determine the allowable design stress for 2.25 Cr-1Mo at 875°F for a design life of 100,000 hours based on minimum properties. .....................................................21 11.9 Problem 9 – Determine the allowable design stress for 304L SS at 1050°F for a design life of 100,000 hours based on minimum properties. .................................................................25 11.10 Problem 10 – Determine the allowable design stress for 347H SS at 1250°F for a design life of 100,000 hours based on minimum properties. .....................................................27 11.11 Problem 11 – Develop a plot of service life as a function of stress and temperature for 2.25Cr-1Mo based on the minimum Larson-Miller Parameter. ..................................................29 11.12 Problem 12 – Develop a plot of rupture strength versus temperature for 2.25 Cr-1Mo at a service life of 100,000 hours using both the average and minimum Larson-Miller parameters. .....................................................................................................................................31 12 Tables ............................................................................................................................................33 13 Technical Basis ............................................................................................................................53 13.1 Overview ...............................................................................................................................53 13.2 Low Carbon Steel ................................................................................................................54 13.3 Medium Carbon Steel ..........................................................................................................58 13.4 C-0.5Mo .................................................................................................................................62 13.5 1.25Cr-0.5Mo ........................................................................................................................66 13.6 2.25Cr-1Mo ...........................................................................................................................70 13.7 3Cr-1Mo ................................................................................................................................74 13.8 5Cr-0.5Mo .............................................................................................................................78 13.9 5Cr-0.5Mo-Si.........................................................................................................................82 13.10 7Cr-0.5Mo .............................................................................................................................86 13.11 9Cr-1Mo ................................................................................................................................90 13.12 9Cr-1Mo-0.25V......................................................................................................................94

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13.13 13.14 13.15 13.16 13.17 13.18 13.19 13.20 13.21 13.22 13.23 13.24 13.25

Type 304L Stainless Steel ..................................................................................................98 Type 304 & 304H Stainless Steel .....................................................................................102 Type 316L Stainless Steel ................................................................................................106 Type 316 & 316H Stainless Steel .....................................................................................110 Type 317L Stainless Steel ................................................................................................114 Type 321 Stainless Steel ...................................................................................................119 Type 321H Stainless Steel ................................................................................................123 Type 347 Stainless Steel ...................................................................................................127 Type 347H Stainless Steel ................................................................................................131 Alloy 800 .............................................................................................................................135 Alloy 800H ..........................................................................................................................139 Alloy 800HT ........................................................................................................................143 HK-40 ..................................................................................................................................147


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ABSTRACT Mechanical property data for alloys currently produced and used for petroleum refinery heater applications have been gathered and analyzed using systematic computerized statistical data fitting methods. Properties reported for each material are elevated temperature yield and tensile strength, minimum and average stress-rupture strength and stress-rupture exponent at temperature. Data gathered were representative of materials produced by modern production methods. The results of the analyses were presented using polynomial equations for stress and temperature dependence of the properties. Stress-rupture test results were used to develop Larson-Miller parameter relations based on optimized constants for each alloy. Parameter plots for each alloy compare the properties shown in API 530 with those obtained from the current analyses. Materials included are low and medium carbon steels, carbon- 0.5mo steel, 1 ¼ Cr-1/2 Mo steel, 2 ¼ Cr-1 Mo, 3Cr-1 Mo steel and 5, 7 and 9 Cr-Mo steels , 9 Cr-1Mo-V steel, 304, 316, 317, 321 and 347 stainless steels (ordinary and H grades where applicable), alloys 800, 800H and 800HT and HK-40. Examples are provided demonstrating application of the polynomial equations to common problems such as determining design life at temperature and design allowable stress.

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1

INTRODUCTION

The materials data presented in this publication were obtained from materials produced more recently than those used in preparing prior editions of API RP530 for the design of fired heater tubes. The data for this project were gathered by the Materials Properties Council (MPC) under API contract from test results for materials produced and tested at facilities not in the United States (US). The data collections for prior editions of API RP 530 were limited to US sources. The new data for each alloy were evaluated using modern computerized statistical regression methods and the results compared graphically to the previously published properties. The coefficients for the polynomials resulting from the regression analysis of the newer materials are presented in tabular form in this document to facilitate computer implementation for design and life assessment. The material data required for a design calculation in accordance with RP530/ISO 13704 are yield strength, ultimate tensile strength, stress-rupture exponent, and minimum and average stress rupture properties as described using Larson-Miller Parameter equations. This information is used to obtain the time-independent or elastic allowable stress and the time-dependent or rupture allowable stresses used in determining the required wall thickness of a fired heater tube or bend for a specified service life and temperature. The sections that follow immediately below describe each of the properties presented for each of the materials. A series of examples in subsequent sections illustrate application of the analytical equations used to represent the properties. The final sections of this report provide in tabular and graphical form the yield strength, ultimate tensile strength, and the minimum and average stress rupture properties. Comparisons of the properties determined under this project with those in the prior edition of API RP530/ISO 13704 are shown.

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YIELD STRENGTH

Equation (1) is used to represent the yield strength as a function of temperature. The coefficients for use in this equation for each of the materials in API RP530/ISO 13704 are provided in Table 1.

(

⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤ ⎦

σ ys = σ ysrt ⋅ 10⎣

)

( ksi, F ) o

(1)

The yield strength at temperatures above room temperature may be calculated using this equation by multiplying the yield strength value at room temperature by a temperature dependent ratio term. If σ ysrt chosen for this equation is the specified minimum room temperature value of yield strength, then the resulting value at a higher temperature can be taken as an estimate of the minimum value at that temperature. If the average room temperature value of yield strength for a data set is used in Equation(1), then the resulting value at the higher temperature can be taken as the best estimate of the average value at that temperature. The ratios are deemed to be applicable over the range of commonly provided and heat treatments and compositions for the respective materials.

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ULTIMATE TENSILE STRENGTH

Equation (2) is in the same form as Equation (1) and is used to represent the ultimate tensile strength as a function of temperature. The coefficients also are provided in Table 1.

(

⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤ ⎦

rt σ uts = σ uts ⋅ 10 ⎣

)

( ksi, F ) o

(2)

The ultimate tensile strength at temperatures above room temperature may be calculated using this equation by multiplying the ultimate tensile strength value at room temperature by a temperature dependent ratio term presented in the parenthesis. If the specified minimum room temperature value of ultimate tensile strength is used in Equation (2), then the resulting value at temperature is an estimate of the minimum value at a higher temperature. If the average room temperature value of ultimate tensile strength of a data set is used in Equation (2), then at a higher temperature one obtains an estimate of the corresponding average value.


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4

TIME-INDEPENDENT ALLOWABLE STRESS

As shown in Table 2 and Equation (3), the time-independent or elastic allowable stress for each alloy is proportional to the yield strength over a specific range of temperatures.

S e = Fed ⋅ σ ys

5

(3)

LARSON-MILLER PARAMETER

The Larson Miller Parameter (LMP) provides a relationship between stress, time to failure (taken here to mean test, service or design life, Ld ,) and temperature. The basic expression for the Larson-Miller Parameter is given by Equation (4) and Equation (7).

( hours, ksi, F )

LMP (σ ) = (T + 460 ) ( C + log10 [ Ld ])

o

(4)

Equations (5) and (6) are alternate forms of the same equation. In Equation (5) the test time, service or designlife is shown as a function of applied stress and temperature. In Equation (6), the temperature is a function of the applied stress and service life.

Ld = 10

T=

⎡ LMP (σ ) ⎤ −C ⎥ ⎢ ⎢⎣ (T + 460 ) ⎥⎦

( hours , ksi, F )

(5)

( hours, ksi, F )

(6)

o

LMP(σ ) − 460 ( C + log10 [ Ld ])

o

The C coefficient in Equations (4), (5), and (6) is the Larson-Miller Constant. The Larson-Miller constant has been optimized for each material in this study by statistical regression of the repective test results using log time as the dependent variable and log stress and the reciprocal of the absolute temperature as the independent variables. In MPC’s software a value of C is obtained for each lot of material in the data set and then minimum and averages are computed. In Table 3 the somewhat larger values shown the minimum constant entries are appropriate to represent the variance expected at a 95% confidence interval. In this document, the Larson-Miller Parameter for each material is presented as a polynomial in log10 of stress in the form given by Equation (7). The coefficients of Equation (7) for each material are provided in Table 3. The Larson-Miller constant, C , applicable to the average and minimum properties for each material is also shown in Table 3.

LMP = A0 + A1 ⋅ log10 [σ ] + A2 ⋅ ( log10 [σ ]) + A3 ⋅ ( log10 [σ ]) 2

3

(7)

The equations for the Larson-Miller Parameter should not be used for temperatures outside the limiting metal temperature ranges shown for each material in Table 3. Note that this treatment of the Larson-Miller Parameter is different from that in API RP530/ISO 13704 6th Edition. In that document, non-optimized Larson-Miller Constants are used for broad material groups, C = 20 for ferrous materials and C = 15 for high alloy and nonferrous (high-nickel) materials. Here alloy specific, optimized Larson-Miller Parameter constants are provided so that the equations represent minimum and average behavior more precisely. Also, extrapolation of behavior with temperature is sensitive to the constant used and the optimized constant should be used .

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6

TIME-DEPENDENT ALLOWABLE STRESS

The time-dependent allowable stress, σ , may be determined from the Larson-Miller Parameter given by Equation (7). The solution is given by Equation (8).

σ = 10− X

(8)

The exponent X in Equation (8) is computed exactly as follows based on the values of the coefficients in Equation (7) as shown below for the cases where first, second and third order polynomials were obtained for the stress dependence of the LMP.. a)

Case 1 – First order.

X = b)

A1 is not equal to zero and A2 and A3 are equal to zero:

A0 − LMP A1

(9)

Case 2 – second order (quadradic) polynomial.

A2 is not equal to zero, A3 is equal to zero, and

A1 can be any value including zero: X= c)

A1 + A12 − 4 A2 ( A0 − LMP ) 2 A2

Case 3 – third order polynomial

(10)

A3 is not equal to zero, and A1 and A2 can be any values

including zero:

X =

A2 Q −S− 3 A3 S

(11)

where, 2 ⎛ A ⎞⎤ 1 ⎡⎛ A2 ⎞ Q = ⎢⎜ ⎟ − 3 ⎜ 1 ⎟ ⎥ 9 ⎢⎝ A3 ⎠ ⎝ A3 ⎠⎥⎦ ⎣

(12)

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⎛A ⎞ ⎛AA ⎞ ⎛ A − LMP ⎞ 2 ⎜ 2 ⎟ − 9 ⎜ 2 2 1 ⎟ + 27 ⎜ 0 ⎟ A3 ⎠ A3 ⎠ A3 ⎝ ⎝ ⎝ ⎠ R= 54

(

⎛ R⎞ S = − ⎜⎜ ⎟⎟ R + R 2 − Q3 ⎝ R⎠ 7

)

1 3

(13)

(14)

RUPTURE EXPONENT

The rupture exponent can be obtained from the first derivative of log time with respect to stress at any temperature. For the design calculation procedure in API RP530/ISO 13704 the rupture exponents were determined between the 60,000-hour and 100,000-hour times for the minimum rupture strengths determined from the Larson-Miller parameter curves. The following equation was used to calculate for the rupture exponent, n , at various temperatures.

n=

log10 [100,000] − log [ 60,000] log ⎡⎣ S100,000 ⎤⎦ − log ⎡⎣ S60,000 ⎤⎦


(15)

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the values of the rupture exponents so obtained were fitted with up to a a fifth order polynomial as shown in Equation (16). The resulting coefficients are presented in Table 4. It should be noted that the r2 value for each fit was always very close to 1.

n = C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5

8

(16)

APPLICABLE ASTM SPECIFICATIONS

The applicable ASTM specifications for the generic material types that data are provided for are shown in Table 5.

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MATERIAL PHYSICAL PROPERTIES

Physical properties for materials that may be required in heat transfer and stress calculations (i.e., modulus of elasticity, thermal expansion coefficient, thermal conductivity, and thermal diffusivity) may be obtained from WRC 503 for the materials covered in this document.

10 NOMENCLATURE

A0 → A5

coefficients used to determine the minimum and average Larson-Miller parameter as a function of stress, as applicable.

C

Larson-Miller Constant, average or minimum value as applicable.

Cavg

Larson-Miller Constant, average properties.

Cmin

Larson-Miller Constant, minimum properties.

C0 → C5

coefficients used to determine the yield strength, ultimate tensile strength, and rupture exponent as a function of temperature, as applicable.

Fed

elastic allowable stress design factor.

Ld

service or design life in hours.

LMP n

Larson-Miller Parameter. rupture exponent.

T

Temperature in degrees Fahrenheit.

S 60,000

stress to cause rupture in 60,000 hours.

S100,000

stress to cause rupture in 100,000 hours.

X Q

time-independent allowable stress parameter.

R


S σ



applied stress in ksi.

σ ys

yield stress in ksi.

σ uts

ultimate tensile strength in ksi.

σ ysrt

minimum specified yield strength in ksi at room temperature.

rt σ uts

minimum specified ultimate tensile strength in ksi at room temperature.

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11 EXAMPLE PROBLEMS 11.1 Problem 1 – Calculate the minimum yield and the tensile strength at 400°F, for 2.25Cr1Mo. a)

STEP 1 – Obtain he minimum specified yield strength at room temperature from Table 1. Note that this procedure is applicable to other room temperature strength values.

σ ysrt = 30 ksi b)

(17)

STEP 2 – Determine the minimum yield strength at 400°F using Equations (1) and(18). Equation (18) is also shown in the notes section of Table 1. ⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤ ⎦

σ ys = σ ysrt ⋅10 ⎣ The coefficients,

(18)

C0 through C5 for 2.25Cr-1Mo are determined from Table 1.

C0 = 2.1540371E-02 C1 = -3.2503600E-04 C2 = 2.2155200E-07

(19)

C3 = 4.1358400E-10 C4 = -6.4839900E-13 C5 = 1.5027000E-16 Substituting these values into Equation (18) results in:

σ ys = 26.032 ksi

(20)

or for a value in SI units:

⎛

MPa ⎞

σ ys = 26.032 ksi ⎜ 6.894757 ⎟ = 179.5 MPa ksi ⎠ ⎝ c)

STEP 3 – Determine the minimum specified ultimate tensile strength at room temperature from Table 1. rt σ muts = 60 ksi

d)

(21)

(22)

STEP 4 – Determine the tensile strength at 400°F using Equations (2) and (23). Equation (23) is also shown in the notes section of Table 1. ⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤ ⎦

rt σ uts = σ uts ⋅10⎣

The coefficients,

(23)


C0 = 1.4704266E-02 C1 = -1.9874800E-04 C2 = -2.9115300E-07 C3 = 2.0040500E-09

(24)

C4 = -2.2341400E-12 C5 = 5.9263200E-16 WRC Bulletin 541 Evaluation of Material Strength Data for Use in Conjunction with API 530

11


Substituting these values into Equation (23) results in:

σ uts = 55.451 ksi

(25)

or for a value in SI units:

⎛ ⎝

σ uts = 55.451 ksi ⎜ 6.894757

12

MPa ⎞ ⎟ = 382.3 MPa ksi ⎠


(26)


11.2 Problem 2 – Determine the elastic design stress for 2.25 Cr-1Mo at 500°F. a)

STEP 1 – Determine the minimum specified yield strength at room temperature from Table 1.

σ ysrt = 30 ksi b)

(27)

STEP 2 – Determine the yield strength at 500°F using Equation (28). This equation is also shown in the notes section of Table 1. ⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤ ⎦

σ ys = σ ysrt ⋅10 ⎣ The coefficients,

(28)changed


C0 = 2.1540371E-02 C1 = -3.2503600E-04 C2 = 2.2155200E-07 C3 = 4.1358400E-10

(29)

C4 = -6.4839900E-13 C5 = 1.5027000E-16 Substituting these values into Equation (28) results in:

σ ys = 25.551 ksi c)

STEP 3 – Determine the elastic allowable stress factor from Table 2.

Fed = d)

(30)

2 3

(31)

STEP 4 – Determine the elastic allowable design stress.

⎛2⎞ S e = Fed ⋅ σ ys = ⎜ ⎟ ⋅ 25.551 ksi = 17.034 ksi ⎝3⎠

(32)

or in SI units:

⎛ 6.894757 MPa ⎞ S e = 17.034 ksi ⋅ ⎜ ⎟ = 117.4 MPa ksi ⎝ ⎠


(33)

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11.3 Problem 3 – Develop a plot of stress versus Larson-Miller Parameter (LMP) for 2.25Cr1Mo. a)

STEP 1 – The equation for the Larson-Miller Parameter as a function of stress is given by Equations (7) and (34). This equation is also shown in the notes section of Table 3, and can be used for both average and minimum properties.

LMP = A0 + A1 ⋅ log [σ ] + A2 ⋅ ( log [σ ]) + A3 ⋅ ( log [σ ]) 2

The coefficients,

3

(34)

A0 through A3 for 2.25Cr-1Mo are determined from Table 3.

A0 = 4.3946400E+04 A1 = -8.3900000E+03

(35)

A2 = 0.0 A3 = 0.0 b)

STEP 2 – Develop a table of stress versus the Larson-Miller Parameter, see Table 11.3E. Then plot the Larson-Miller parameter on the x-axis and the stress on the y-axis, see Figure 11.3E. Table 11.3E – Larson-Miller Parameter as a Function of Stress Stress,

σ (ksi)

Larson Miller Parameter, LMP (x10-3)

1 5 10 15 20 25 30 35 40

43.946 38.082 35.556 34.079 33.031 32.218 31.553 30.992 30.505

Stress (ksi)

100

10

2.25Cr-1Mo 1 30

32

34

36

38

40

42

-3

LMP (x10 )

Figure 11.3E – Stress verse Larson-Miller Parameter

14


44


11.4 Problem 4 – Calculate the service life for 2.25Cr-1Mo at 975°F and 10 ksi stress using the minimum and average Larson-Miller Parameters. a)



3

(36)

The Larson-Miller constant, C , for minimum properties, and the coefficients

A0 through A3 for

2.25Cr-1Mo are determined from Table 3.

C = 1.9565607 E + 01 A0 = 4.3946400 E + 04 A1 = -8.3900000 E + 03

(37)

A2 = 0.0 A3 = 0.0 The Larson-Miller constant, C , for average properties, and the coefficients

A0 through A3 for

2.25Cr-1Mo are determined from Table 3. In this case, the parameter C is the only value that differs between the minimum and average material properties. The Larson-Miller constant, C , for average properties is given by Equation (38).

C = 1.8918100E+01 b)

STEP 2 – The service life,

(38)

Ld , can be determined with the information in STEP 1 and Equation

(39), which is shown below.

Ld = 10

⎡ LMP (σ ) ⎤ −C ⎥ ⎢ ⎣⎢ (T + 460 ) ⎦⎥

(39)

For a temperature and stress of 975°F and 10 ksi, the Larson-Miller Parameter and the associated service life, Ld , based on minimum properties are:

LMP = 35556.4

(40)

Ld = 16069.3 hours

(41)

For a temperature and stress of 975°F and 10 ksi, the service life,

Ld , based on average

properties is:

Ld = 724234.3 hours


(42)

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11.5 Problem 5 – Determine the service life for 2.25Cr-1Mo at 515°C and 100 MPa using the minimum and average Larson-Miller Parameters. a)

STEP 1 – Convert the temperature and stress to US Customary units.

T = 1.8 ( 515 o F ) + 32 = 959 o F

(43)

⎛

⎞ 1 ksi ⎟ = 14.504 ksi ⎝ 6.894757 MPa ⎠

σ = 100 MPa ⋅ ⎜ b)

(44)

STEP 2 – The equation for the Larson-Miller Parameter as a function of stress is given by Equations (7) and (45). This equation is also shown in the notes section of Table 3.


3


(45)

A0 through A3 for


C = 1.9565607E+01 A0 = 4.3946400E+04 A1 = -8.3900000E+03

(46)


A0 through A3 for

2.25Cr-1Mo are determined from Table 3. In this case, the parameter C is the only value that differs between the minimum and average material properties. The Larson-Miller constant for average properties, C , is given by Equation (38).

C = 1.8918100E+01 c)


(47)


(48), which is shown below.

Ld = 10

⎡ LMP (σ ) ⎤ −C ⎥ ⎢ ⎣⎢ (T + 460 ) ⎦⎥

(48)

For a temperature and stress of 515°C (959°F) and 100 MPa (14.393 ksi), the Larson-Miller Parameter and service life, Ld , based on minimum properties is:

LMP = 34202

(49)

Ld = 34434 hours

(50)

For a temperature and stress of 515°C (959°F) and 100 MPa (14.393 ksi), the service life,

Ld ,

based on average properties is:

Ld = 152929 hours

16


(51)


11.6 Problem 6 – Determine the Rupture Exponent, n , for 2.25 Cr-1Mo as a function of temperature. a)

STEP 1 – The equation for the Rupture Exponent, n as a function of temperature, T , is given by Equations (16) and (52). This equation is also shown in the notes section of Table 4.

n = C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 b)

STEP 2 – The coefficients,

(52)


C0 = 1.6116223E+01 C1 = -2.2988479E-02 C2 = 2.1835770E-05

(53)

C3 = -1.2833734E-08 C4 = 4.2012778E-12 C5 = -5.8449546E-16 c)

STEP 3 – Develop a table of the Rupture Exponent, n , verse temperature, T , using Equations (52) and (53), see Table 11.6E. Then plot the temperature on the x-axis and the rupture exponent on the y-axis, see Figure 11.6E. Table 11.6E – Rupture Exponent as a Function of Temperature Temperature, 800 850 900 950 1000 1050 1100 1150 1200

T ( oF )

Rupture Exponent, n 6.659 6.405 6.169 5.950 5.747 5.556 5.378 5.211 5.054


17


Rupture Exponenet, n

7.0

6.5

6.0

5.5 2.25Cr-1Mo 5.0 800

850

900

950

1000

1050

1100

1150

Temperature (oF) Figure 11.6E – Rupture Exponent as a Function of Temperature

18


1200


11.7 Problem 7 – Develop a plot of stress verse service life for 2.25 Cr-1Mo at temperatures of 1000°F and 1025°F based on the minimum Larson-Miller constant.

a)

STEP 1 – The equation for the Larson-Miller Parameter as a function of stress, σ is given by Equations (7) and (54). This equation is also shown in the notes section of Table 3.


3

(54)


A0 through A3 for


C = 1.9565607E+01 A0 = 4.3946400E+04 A1 = -8.3900000E+03

(55)

A2 = 0.0 A3 = 0.0 b)



(56).

Ld = 10

⎡ LMP (σ ) ⎤ −C ⎥ ⎢ ⎣⎢ (T + 460 ) ⎦⎥

(56)

Using Equations (54), (55), and (56), the Larson-Miller parameter and service life,

Ld , can be

computed as a function of stress. Data points for 2.25Cr-1Mo at 1000°F and 1025°F, based on the minimum Larson-Miller parameter are shown in Table 11.7E. These data are subsequently used to create the plot shown in Figure 11.7E. Table 11.7E – Sample of Tabulated Values Used to Plot Figure 9.7E

Stress,

σ ( ksi )

Design Life,

LMP

Ld ( hours )

1000 o F

1025 o F

2

4.142E+04

6.3793E+08

2.1240E+08

4

3.890E+04

1.1882E+07

4.2305E+06

6

3.742E+04

1.1560E+06

4.2806E+05

8

3.637E+04

2.2131E+05

8.4260E+04

10

3.556E+04

6.1389E+04

2.3883E+04

12

3.489E+04

2.1531E+04

8.5258E+03

14

3.433E+04

8.8788E+03

3.5686E+03

16

3.384E+04

4.1219E+03

1.6782E+03

18

3.341E+04

2.0948E+03

8.6268E+02

20

3.303E+04

1.1434E+03

4.7569E+02


19


Figure 11.7E – Rupture Stress as a Function of Temperature, Using the Minimum LMP

20



11.8 Problem 8 – Determine the allowable design stress for 2.25 Cr-1Mo at 875°F for a design life of 100,000 hours based on minimum properties.

a)

STEP 1 – Determine the allowable stress based on time-independent or elastic properties. 1) STEP 1.1 – Determine the minimum specified yield strength at room temperature from Table 1.

2)

σ ysrt = 30 ksi

(57)

STEP 1.2 – Determine the yield strength at 875°F using Equations(1) and (58). equation also appears in the notes section of Table 1.

This

⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤ ⎦

σ ys = σ ysrt ⋅10 ⎣

The coefficients,

(58)


C0 = 2.1540371E-02 C1 = -3.2503600E-04 C2 = 2.2155200E-07

(59)

C3 = 4.1358400E-10 C4 = -6.4839900E-13 C5 = 1.5027000E-16 Substituting these values in Equation (58) results in:

σ ys = 22.8005 ksi 3)

STEP 1.3 – Determine the elastic design factor from Table 2.

Fed = 4)

(60)

2 3

STEP 1.4 – Determine the allowable stress based on time-independent properties using Equation (3), the elastic design stress.

⎛2⎞ S e = Fed ⋅ σ ys = ⎜ ⎟ ⋅ 22.8005 ksi = 15.2 ksi ⎝3⎠ b)

(61)

STEP 2 – Determine the allowable stress based on time-dependent properties. 1) STEP 2.1 – The equation for the Larson-Miller Parameter as a function of stress is given by Equation (7) and (62). This equation is also shown in the notes section of Table 3.


3


(62)

A0 through

A3 for 2.25Cr-1Mo are determined from Table 3.


21


C = 1.9565607E+01 A0 = 4.3946400E+04 A1 = -8.3900000E+03

(63)

A2 = 0.0 A3 = 0.0 2)

STEP 2.2 – The larson-Miller parameter may be computed using Equation (4).

LMP (σ ) = (T + 460 ) ( C + log10 [ Ld ])

(64)

or,

LMP = ( 875 + 460 ) (19.565607 + log10 [100, 000 ]) = 32795

(65)

Using Equations (8) and (9), Case 1 in paragraph 6, from the procedure outlined in paragraph 6.0 we have

X =

A0 − LMP ( 4.39464 E 4 − 32795 ) = = −1.32912 A1 −8.39 E 3

St = σ = 10

− ( −1.32912 )

= 21.34 ksi

(66)

(67)

Equation (62) can be solved iteratively for the design stress, σ , which is the independent variable in the Larson-Miller Parameter given by Equation (62), or by using a graphical solution by constructing a plot of stress versus the Larson-Miller Parameter. Data points for 2.25Cr-1Mo at 875°F based on the minimum Larson-Miller parameter are shown in Table 11.8E. These data are subsequently used to create the plot shown in Figure 11.8E. The stress corresponding to the Larson-Miller parameter given by (65) is:

St = 21.34 ksi

22


(68)


Table 11.8E – Sample of Tabulated Values Used to Plot Figure 11.8E

LMP

Stress,

σ ( ksi )

32853

21.00

32844

21.05

32836

21.10

32827

21.15

32818

21.20

32810

21.25

32801

21.30

32795

21.336

32793

21.35

32784

21.40

32776

21.45

32767

21.50

32759

21.55

32750

21.60

32742

21.65

32734

21.70

32725

21.75

32717

21.80

32708

21.85

32700

21.90

32692

21.95

32683

22.00


23


Stress (ksi)

100

10

1 30000

32000

34000

36000

38000

40000

42000

44000

LMP

c)

Figure 11.8E – Graphical Solution to Problem 8 STEP 3 – The allowable design stress is determined by taking the minimum value of the time dependent and time independent stress values obtained from STEPS 1 and 2, respectively.

S = min [ S e , St ] = min [15.2 ksi, 21.34 ksi ] = 15.2 ksi

24


(69)


11.9 Problem 9 – Determine the allowable design stress for 304L SS at 1050°F for a design life of 100,000 hours based on minimum properties.

a)


σ ysrt = 25 ksi 2)

(70)

STEP 1.2 – Determine the yield strength at 1050°F using Equations(1) and (58). This equation also appears in the notes section of Table 1. ⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤ ⎦


The coefficients,

(71)

C0 through C5 for 304L SS are determined from Table 1.

C0 = 4.5888791E-02 C1 = -6.9508400E-04 C2 = 5.7950900E-07

(72)

C3 = -2.1178000E-10 C4 = 6.5466400E-15 C5 = -1.2730800E-17 Substituting these values in Equation (58) results in:

σ ys = 12.5732 ksi 3)

(73)


Fed = 0.9 4)


S e = Fed ⋅ σ ys = ( 0.9 ) ⋅12.5732 ksi = 11.32 ksi b)

(74)



3


(75)

A0 through

A3 for 304L SS are determined from Table 3. C = 1.8287902E+01 A0 = 4.6172960E+04 A1 = -8.4187000E+03

(76)

A2 = -1.4620000E+03 A3 = 0.0 2)

STEP 2.2 – The larson-Miller parameter may be computed using Equation (4). WRC Bulletin 541 Evaluation of Material Strength Data for Use in Conjunction with API 530

25


LMP (σ ) = (T + 460 ) ( C + log10 [ Ld ])

(77)

or,

LMP = (1050 + 460 ) (18.288 + log10 [100, 000 ]) = 35165

(78)

Using Equations (8) and (10), Case 2 in paragraph 6, from the procedure outlined in paragraph 6.0 we have

-8.42E3 + (-8.42E3)2 − 4(-1.462E3)(46170 − 35165) X= = −1.09791 2(-1.462E3) St = σ = 10 c)

− ( −1.09791)

= 12.529 ksi

(80)

STEP 3 – The allowable design stress is determined by taking the minimum value of the time dependent and time independent stress values obtained from STEPS 1 and 2, respectively.


26

(79)


(81)


11.10 Problem 10 – Determine the allowable design stress for 347H SS at 1250°F for a design life of 100,000 hours based on minimum properties.

a)


σ ysrt = 30 ksi 2)

(82)

STEP 1.2 – Determine the yield strength at 1250°F using Equations(1) and (58). This equation also appears in the notes section of Table 1. ⎡C0 + C1T + C2T 2 + C3T 3 + C4T 4 + C5T 5 ⎤ ⎦


The coefficients,

(83)

C0 through C5 for 347H SS are determined from Table 1.

C0 = 4.9734437E-02 C1 = -8.6863733E-04 C2 = 2.5602354E-06

(84)

C3 = -4.5554196E-09 C4 = 3.7224192E-12 C5 = -1.0967259E-15 Substituting these values in Equation (58) results in:

σ ys = 19.3 ksi 3)

(85)


Fed = 0.9 4)


S e = Fed ⋅ σ ys = 0.9 ⋅19.3 ksi = 17.4 ksi b)

(86)



3


(87)

A0 through

A3 for 347H SS are determined from Table 3. C = 1.417E+01 A0 = 3.9536020E+04 A1 = -1.2225330E+04

(88)

A2 = 6.7502400E+03 A3 = -2.8722460E+03 2)

STEP 2.2 – The Larson-Miller parameter may be computed using Equation (4). WRC Bulletin 541 Evaluation of Material Strength Data for Use in Conjunction with API 530

27


LMP (σ ) = (T + 460 ) ( C + log10 [ Ld ])

(89)

or,

LMP = (1250 + 460 ) (14.17 + log10 [100, 000 ]) = 32781

(90)

Using Equations (8) and (11), Case 3 in paragraph 6, through (14) from the procedure outlined in paragraph 6.0 we have 2 ⎛ A ⎞⎤ 1 ⎡⎛ A2 ⎞ Q = ⎢⎜ ⎟ − 3 ⎜ 1 ⎟ ⎥ 9 ⎢⎝ A3 ⎠ ⎝ A3 ⎠ ⎥⎦ ⎣ 2 ⎛ -1.223 ×104 ⎞ ⎤ 1 ⎡⎛ 6.75 ×103 ⎞ Q = ⎢⎜ ⎟ − 3⎜ ⎟⎥ = -0.8051 9 ⎢⎝ -2.87 ×103 ⎠ -2.872 ×103 ⎠ ⎥ ⎝ ⎣ ⎦

(91)

3

⎛A ⎞ ⎛AA ⎞ ⎛ A − LMP ⎞ 2 ⎜ 2 ⎟ − 9 ⎜ 2 2 1 ⎟ + 27 ⎜ 0 ⎟ A3 ⎠ A3 ⎠ A3 ⎝ ⎝ ⎝ ⎠ R= 54 3 ⎛ ⎛ 6.75 ×103 ⎞ ⎡ 6.75 ×103 × -1.22 × 104 ⎤ ⎞ ⎜ 2⎜ 9 − ⎢ ⎥ +⎟ 3 ⎟ (-2.87 ×103 ) 2 ⎜ ⎝ -2.87 × 10 ⎠ ⎣ ⎦ ⎟ ⎜ ⎟ 4 ⎜ 27 ⎡ 3.95 ×10 - ( 32781) ⎤ ⎟ ⎥ 3 ⎜ ⎢ ⎟ × -2.872 10 ⎣ ⎦ ⎝ ⎠ = 0.010465 R= 54

(

⎛ R ⎞ S = − ⎜⎜ ⎟⎟ R + R 2 − Q 3 ⎝ R ⎠

)

1 3

(

⎛ 0.010465 ⎞ S = − ⎜⎜ ⎟⎟ 0.010465 + 0.010465 ⎝ ⎠

c)

( 0.010465 )

2

− ( −0.8051)

X =

A2 Q −S − 3 A3 S

X =

6.750 × 10 3 −0.8051 − (-0.90162) − = -0.77472 3 3 × (-2.872 × 10 ) -0.90162

St = σ = 10

− ( -0.77472 )

3

)

1 3

= -0.90162

= 5.953 ksi

(93)

(94) (95)

STEP 3 – The allowable design stress is determined by taking the minimum value of the time dependent and time independent stress values obtained from STEPS 1 and 2, respectively.


28

(92)


(96)


11.11 Problem 11 – Develop a plot of service life as a function of stress and temperature for 2.25Cr-1Mo based on the minimum Larson-Miller Parameter.

a)

STEP 1 – The relation for the Larson-Miller Parameter as a function of stress is given by Equations (7) and (97). This equation is also shown in the notes section of Table 3.


3


(97)

A0 through A3 for


C = 1.9565607E+01 A0 = 4.3946400E+04 A1 = -8.3900000E+03

(98)

A2 = 0.0 A3 = 0.0 An equation that provides the service life as a function of stress and temperature can be obtained by combining Equation (5) and Equation (97). ⎡ A + A ⋅log [σ ]+ A ⋅( log [σ ])2 + A ⋅( log [σ ])3 ⎤ 2 10 3 10 ⎢ 0 1 10 −C ⎥ ⎢ ⎥ T +460) ( ⎣ ⎦

Ld = 10 b)

(99)

STEP 2 – Develop a table of the service life, Ld , for 20,000, 40,000, 60,000, and 100,000 hours versus stress using Equation (99), see Table 11.9E. A plot of the service lives versus stress is shown in Figure 11.9E.

Table 11.11E – ServiceTemperatures for indicated Service Lives Stress,

σ ( ksi )

Service life , hours

20, 000

40, 000

60,000

100,000

5

1136

1116

1104

1090

10

1030

1011

1001

987

15

968

950

940

927

20

924

907

897

885

25

890

873

863

851

30

862

846

836

824

35

839

822

813

802

40

818

802

793

782


29


Stress (ksi)

100

10

20,000 Hours 40,000 Hours 60,000 Hours 100,000 Hours 1 800

850

900

950

1000

1050

1100

1150

Temperature (oF) Figure 11.1E – Service Life as a Function of Stress and Temperature

30


1200


11.12 Problem 12 – Develop a plot of rupture strength versus temperature for 2.25 Cr-1Mo at a service life of 100,000 hours using both the average and minimum Larson-Miller parameters.

a)



3

(100)

A0 through A3 for

The Larson-Miller constant, C , for minimum properties, and the coefficients 2.25Cr-1Mo are determined from Table 3.

C = 1.9565607E+01 A0 = 4.3946400E+04 A1 = -8.3900000E+03

(101)


A0 through A3 for

2.25Cr-1Mo are determined from Table 3. However, C is the only value that is unique between minimum and average parameters. The Larson-Miller constant for average properties, C , is given by Equation (102).

C = 1.8918100E+01

(102)

An equation that provides the temperature as a function of stress and design life can be obtained by combining Equation (6) and Equation (100).

A0 + A1 ⋅ log10 [σ ] + A2 ⋅ ( log10 [σ ]) + A3 ⋅ ( log10 [σ ]) 2

T (σ , Ld ) =

3

( C + log [ L ]) 10

− 460

(103)

− 460

(104)

d

For 100,000 hours, Equation (104) becomes:


T (σ , Ld ) =

3

( C + log [100, 000]) 10

b)

STEP 2 – Develop a table of temperature versus stress based on the minimum and average properties using Equation (104), see Table 11.12E. The data in this table are plotted in Figure 11.12E. In Table 11.12E, the temperatures in the column labeled Minimum Properties are determined using Equation (104) with the Larson-Miller constant for minimum properties in Equation (104), and the temperatures in the column labeled Average Properties are determined using the Larson-Miller constant for average properties, or from Eqaution (104):


T (σ , Ld )

minimum properties

=

(C

min

+ log10 [100, 000])


T (σ , Ld )

average properties

=

3

(C

avg + log10 [100,000] )


− 460

(105)

− 460

(106)

3

31


Table 11.12E – Rupture Stress vs. Temperature for a Service Life of 100,000 Hours Temperature,

σ ( ksi )

Stress,

T

( F) o

Minimum Properties

Average Properties

5

1090

1132

10

987

1027

15

927

965

20

885

921

25

851

887

30

824

859

35

802

836

40

782

815

Stress (ksi)

100

10

Average LMP Minimum LMP 1 800

850

900

950

1000

1050

1100

1150

1200

Temperature (oF) Figure 11.12E – Rupture Stress vs. Temperature for a Service Life of 100,000 Hours

32



12 TABLES Table 1 – Minimum Yield and Tensile Strength as a Function Of Temperature (°F) Material

Parameter

Yield Strength (ksi)

Tensile Strength (ksi)

26

47

C0

1.4088389E-02

1.0807518E-01

C1

-1.9932341E-04

-2.3290664E-03

C2

-2.0694516E-08

1.2941407E-05

C3

-1.0013720E-10

-2.6166794E-08

C4

0

2.2225699E-11

C5

0

-7.0569264E-15

σ rt

35

60

C0

1.4088389E-02

1.0807518E-01

C1

-1.9932341E-04

-2.3290664E-03

C2

-2.0694516E-08

1.2941407E-05

C3

-1.0013720E-10

-2.6166794E-08

C4

0

2.2225699E-11

C5

0

-7.0569264E-15

σ rt

30

52

C0

1.3089229E-02

1.1433749E-01

C1

-1.9903245E-04

-2.4719083E-03

C2

1.8433603E-07

1.3823832E-05

C3

-1.7552202E-10

-2.7995759E-08

C4

0

2.3927060E-11

C5

0

-7.5170846E-15

σ rt

30

60

C0

2.1540371E-02

1.4704266E-02

C1

-3.2503600E-04

-1.9874800E-04

C2

2.2155200E-07

-2.9115300E-07

C3

4.1358400E-10

2.0040500E-09

C4

-6.4839900E-13

-2.2341400E-12

C5

1.5027000E-16

5.9263200E-16

σ

Low Carbon Steel

Medium Carbon Steel

C-0.5Mo

1.25Cr-0.5Mo

rt


33


Table 1 – Minimum Yield and Tensile Strength as a Function Of Temperature (°F) Material

2.25Cr-1Mo

3Cr-1Mo

5Cr-0.5Mo

5Cr-0.5Mo-Si

34

Parameter



σ rt

30

60

C0

2.1540371E-02

1.4704266E-02

C1

-3.2503600E-04

-1.9874800E-04

C2

2.2155200E-07

-2.9115300E-07

C3

4.1358400E-10

2.0040500E-09

C4

-6.4839900E-13

-2.2341400E-12

C5

1.5027000E-16

5.9263200E-16

σ rt

30

60

C0

4.4186141E-02

4.3741544E-02

C1

-7.1542041E-04

-7.3028160E-04

C2

1.2664132E-06

1.6372698E-06

C3

-9.3458131E-10

-1.9656642E-09

C4

3.6214293E-13

1.2727055E-12

C5

-1.6088326E-16

-4.6917217E-16

σ rt

30

60

C0

1.2855425E-02

-1.5076613E-03

C1

-1.9373113E-04

1.6602155E-04

C2

1.2449247E-07

-2.4425324E-06

C3

3.0404621E-10

5.7486446E-09

C4

-3.5555955E-13

-4.9777060E-12

C5

-5.7953915E-18

1.3635365E-15

σ rt

30

60

C0

1.2855425E-02

-1.5076613E-03

C1

-1.9373113E-04

1.6602155E-04

C2

1.2449247E-07

-2.4425324E-06

C3

3.0404621E-10

5.7486446E-09

C4

-3.5555955E-13

-4.9777060E-12

C5

-5.7953915E-18

1.3635365E-15




7Cr-0.5Mo

9Cr-1Mo

9Cr-1Mo-V

Type 304L SS

Parameter



σ rt

30

60

C0

1.3532100E-01

9.9054977E-03

C1

-2.5870657E-03

-1.7559652E-04

C2

1.0664886E-05

5.5881927E-07

C3

-2.0092622E-08

-1.0648485E-09

C4

1.7366385E-11

5.6685649E-13

C5

-5.6740415E-15

-1.9197713E-16

σ rt

30

60

C0

1.3571242E-02

2.1597188E-02

C1

-1.7082315E-04

-3.1031668E-04

C2

-4.3400952E-07

-6.1394577E-08

C3

1.6036654E-09

1.3545273E-09

C4

-1.5678560E-12

-1.6448546E-12

C5

3.6386453E-16

4.1818392E-16

σ rt

60

85

C0

3.3650472E-02

1.8096292E-02

C1

-5.5446746E-04

-2.5065398E-04

C2

1.0944031E-06

-1.9394875E-07

C3

-5.7019722E-10

1.2610086E-09

C4

-1.9770030E-13

-1.3855450E-12

C5

0

3.4264520E-16

σ rt

25

70

C0

4.5888791E-02

7.7361661E-02

C1

-6.9508400E-04

-1.2718700E-03

C2

5.7950900E-07

2.4999900E-06

C3

-2.1178000E-10

-1.7023100E-09

C4

6.5466400E-15

1.2739600E-13

C5

-1.2730800E-17

7.2563700E-17


35



Type 304/304H SS

Type 316L SS

Type 316/316H SS

Type 317L SS

36

Parameter



σ rt

30

75

C0

9.8188514E-03

6.7196226E-02

C1

-5.0551619E-05

-1.1080527E-03

C2

-1.4866719E-06

2.2413756E-06

C3

3.0912775E-09

-1.8350694E-09

C4

-2.3688742E-12

5.9804933E-13

C5

6.0840262E-16

-1.2196459E-16

σ rt

25

70

C0

4.947300E-02

2.825000E-02

C1

-7.820685E-04

-3.814120E-04

C2

9.205307E-07

-1.664940E-07

C3

-9.753774E-10

1.406040E-09

C4

7.836576E-13

-1.341640E-12

C5

-2.709835E-16

3.241850E-16

σ rt

30

75

C0

1.2001323E-02

3.2859229E-02

C1

-8.8000344E-05

-5.1714106E-04

C2

-1.5040192E-06

4.6118780E-07

C3

3.1425000E-09

6.1438157E-10

C4

-2.4201238E-12

-9.2054227E-13

C5

6.4067530E-16

2.2901104E-16

σ rt

25

70

C0

4.947300E-02

2.825000E-02

C1

-7.820685E-04

-3.814120E-04

C2

9.205307E-07

-1.664940E-07

C3

-9.753774E-10

1.406040E-09

C4

7.836576E-13

-1.341640E-12

C5

-2.709835E-16

3.241850E-16




Type 321 SS

Type 321H SS

Type 347 SS

Type 347H SS

Parameter



σ rt

30

75

C0

6.863218E-02

6.278852E-02

C1

-1.184702E-03

-1.080116E-03

C2

3.244156E-06

2.863153E-06

C3

-4.905795E-09

-3.697114E-09

C4

3.536365E-12

2.478506E-12

C5

-9.654898E-16

-7.256524E-16

σ rt

25

70

C0

1.0112716E-02

5.1423451E-02

C1

-1.4446737E-04

-8.3118863E-04

C2

0

1.4451218E-06

C3

0

-9.5441766E-10

C4

0

2.5659891E-13

C5

0

-8.2941763E-17

σ rt

30

75

C0

4.9734437E-02

6.9844688E-02

C1

-8.6863733E-04

-1.2173646E-03

C2

2.5602354E-06

3.4825694E-06

C3

-4.5554196E-09

-5.2044883E-09

C4

3.7224192E-12

3.8869832E-12

C5

-1.0967259E-15

-1.1567466E-15

σ rt

30

75

C0

4.9734437E-02

6.9844688E-02

C1

-8.6863733E-04

-1.2173646E-03

C2

2.5602354E-06

3.4825694E-06

C3

-4.5554196E-09

-5.2044883E-09

C4

3.7224192E-12

3.8869832E-12

C5

-1.0967259E-15

-1.1567466E-15


37



Alloy 800

Alloy 800H

Alloy 800HT

38

Parameter



σ rt

30

75

C0

3.4030711E-02

3.4512216E-02

C1

-5.9044935E-04

-6.1931709E-04

C2

1.6819983E-06

2.0239806E-06

C3

-2.9084079E-09

-3.3262726E-09

C4

2.4078033E-12

2.7021246E-12

C5

-7.5887806E-16

-8.8727065E-16

σ rt

25

65

C0

9.1352894E-03

8.4274949E-04

C1

-6.7153045E-05

8.2765885E-05

C2

-1.0330418E-06

-1.5893549E-06

C3

1.9114308E-09

3.5471048E-09

C4

-1.1936454E-12

-2.7606359E-12

C5

2.1862178E-16

6.5642052E-16

σ rt

25

65

C0

3.4727533E-02

9.1734120E-03

C1

-5.3949644E-04

-4.3023314E-05

C2

6.3686186E-07

-1.5560083E-06

C3

-2.3816323E-10

4.5571519E-09

C4

-7.1132721E-14

-4.2665496E-12

C5

-4.2576695E-18

1.1882810E-15




HK-40

Parameter



σ rt

35

62

C0

4.3689351E-03

4.7208139E-03

C1

4.5144996E-05

-1.3979452E-07

C2

-1.7279747E-06

-1.1239086E-06

C3

2.8459599E-09

2.4482148E-09

C4

-1.6093404E-12

-1.8461449E-12

C5

2.7808712E-16

4.2367166E-16

Notes: 1. In the parameter column, the term yield strength,

σ rt

is used to represent the room temperature value of the

rt . σ ysrt , and the room temperature value of the ultimate tensile strength, σ uts

2. The yield strength as a function of temperature is computed using Equation (1). 3. The tensile strength as a function of temperature is computed using Equation (2).


39


Table 2 – Elastic Allowable Stress Factor and Applicable Temperature Range Elastic Allowable Stress Design Factor

Material

Applicable Temperature Range (°F)

Fed

Minimum

Maximum

Low Carbon Steel

2/3

70

1000

Medium Carbon Steel

2/3

70

1000

C-0.5Mo

2/3

70

1050

1.25Cr-0.5Mo

2/3

70

1200

2.25Cr-1Mo

2/3

70

1200

3Cr-1Mo

2/3

70

1200

5Cr-0.5Mo

2/3

70

1200

5Cr-0.5Mo-Si

2/3

70

1200

7Cr-0.5Mo

2/3

70

1200

9Cr-1Mo

2/3

70

1300

9Cr-1Mo-V

2/3

70

1300

Type 304L SS

0.9

70

1500

Type 304/304H SS

0.9

70

1500

Type 316L SS

0.9

70

1500

Type 316/316H SS

0.9

70

1500

Type 317L SS

0.9

70

1500

Type 321 SS

0.9

70

1500

Type 321H SS

0.9

70

1500

Type 347 SS

0.9

70

1500

Type 347H SS

0.9

70

1500

Alloy 800

0.9

70

1500

Alloy 800H

0.9

70

1650

Alloy 800HT

0.9

70

1850

HK-40

0.9

70

1850

40



Table 3 – Minimum and Average Larson-Miller Parameters as a Function of Stress

Material

Parameter

Temperature Range (˚F)

C Low Carbon Steel

700-1000 1.8150000E+01

3.5093240E+04

A1

-3.6037901E+03

A2

-1.9136590E+03

A3

-250


700-1000 1.5600000E+01

3.2068370E+04

A1

-3.3755550E+03

A2

-1.5933910E+03

A3

-3.0000000E+02

C

1.8725370E+01

3.8792100E+04

A1

-4.9502240E+03

A2

0

A3

0


800-1200 22.054

21.558

A0

4.6354380E+04

A1

-6.9466030E+03

A2

-3.4367510E+02

A3

0


800-1200

C 2.25Cr-1Mo

700-1050 1.9007756E+01

A0

C 1.25Cr-0.5Mo

1.5150000E+01

A0


C-0.5 Mo

1.7700000E+01

A0

C Medium Carbon Steel

Larson-Miller Constant and Parameter vs. Stress: Average Properties

Larson-Miller Constant and Parameter vs. Stress: Minimum Properties

1.9565607E+01

1.8918100E+01

A0

4.3946400E+04

A1

-8.3900000E+03

A2

0

A3

0


41



Material

Parameter


3Cr-1Mo

5Cr-0.5Mo

C

900-1200 1.5785226E+01 1.5381060E+01

A0

3.7264510E+04

A1

-7.9439300E+03

A2

0

A3

0


C

900-1200 1.6025829E+01 1.5589280E+01

A0

3.7264510E+04

A1

-7.9439300E+03

A2

0

A3

0


C 5Cr-0.5Mo-Si

7Cr-0.5Mo

42

900-1200 1.6025829E+01

1.5589280E+01

A0

3.7264510E+04

A1

-7.9439300E+03

A2

0

A3

0


C

900-1200 2.0437460E+01 1.9620550E+01

A0

4.5219510E+04

A1

-1.0217000E+04

A2

5.2679960E+00

A3

-6.3855690E+00


900-1300

C 9Cr-1Mo



2.6223587E+01

2.5859090E+01

A0

5.4758000E+04

A1

-6.1891000E+03

A2

-1.7309000E+03

A3

-6.7715000E+02




Material

Parameter


9Cr-1Mo-V

Type 304L SS

C

900-1300 3.0886006E+01 3.0364230E+01

A0

6.3450000E+04

A1

-1.3800000E+03

A2

-5.1395320E+03

A3

0


C

900-1500 1.8287902E+01 1.7550000E+01

A0

4.6172960E+04

A1

-8.4187000E+03

A2

-1.4620000E+03

A3

0


C Type 304/304H SS

Type 316L SS

1000-1500 1.6145903E+01

1.5521950E+01

A0

4.3539460E+04

A1

-9.7318000E+03

A2

0

A3

0


C

900-1500 1.5740107E+01 1.5200000E+01

A0

4.1483380E+04

A1

-6.0606000E+03

A2

-1.7620000E+03

A3

0


1000-1500

C Type 316/316H SS



1.6764145E+01

1.6309870E+01

A0

4.4933830E+04

A1

-9.4286740E+03

A2

0

A3

0


43



Material

Parameter


Type 317L SS

C

900-1500 1.5740107E+01 1.5200000E+01

A0

4.1483380E+04

A1

-6.0606000E+03

A2

-1.7620000E+03

A3

0


900-1500

C Type 321 SS

1.332500E+01

3.571361E+04

A1

-5.655000E+03

A2

-7.640000E+02

A3

0

C

Type 347 SS

44

900-1500 1.5293986E+01

1.4759580E+01

A0

4.0541580E+04

A1

-6.5212870E+03

A2

-9.7543650E+02

A3

0


C

900-1500 1.4889042E+01 1.4250000E+01

A0

3.7960000E+04

A1

-7.1172160E+03

A2

3.1133520E+03

A3

-2.3000000E+03


900-1500

C Type 347H SS

1.280000E+01

A0


Type 321H SS



14.17

13.65

A0

3.9536020E+04

A1

-1.2225330E+04

A2

6.7502400E+03

A3

-2.8722460E+03




Material

Parameter


Alloy 800

C

900-1500 1.7005384E+01 1.6508780E+01

A0

4.3171030E+04

A1

-8.1470000E+03

A2

0

A3

0


1000-1650

C Alloy 800H

1.6042270E+01

4.5864990E+04

A1

-9.2709340E+03

A2

-1.9293220E+03

A3

7.0913170E+02

C

HK-40

1.6564046E+01

A0


Alloy 800HT



900-1850 1.3606722E+01

1.3234100E+01

A0

4.0112700E+04

A1

-9.0816690E+03

A2

0

A3

0


C

1400-1850 1.0856489E+01 1.0489900E+01

A0

3.4132000E+04

A1

-7.7078820E+03

A2

-9.4500000E+02

A3

0

Note: The average and minimum Larson-Miller Parameter is computed using Equation (7) with the appropriate coefficients from this table.


45


Table 4 – Rupture Exponents as a Function of Temperature Material

Low Carbon Steel

Medium Carbon Steel

C-0.5 Mo

1.25Cr-0.5Mo

46

Parameter

Rupture Exponent – n


700-1000

C0

2.3405940E+01

C1

-2.4087544E-02

C2

4.4283728E-06

C3

0

C4

0

C5

0


700-1000

C0

2.9832967E+01

C1

-4.8908169E-02

C2

3.3126428E-05

C3

-1.0132081E-08

C4

0

C5

0


700-1050

C0

8.98300

C1

-1.1316171E-02

C2

9.0861459E-06

C3

-4.3999472E-09

C4

1.1678546E-12

C5

-1.3028530E-16


800-1200

C0

1.7939223E+01

C1

-2.6358008E-02

C2

2.2487501E-05

C3

-1.1762993E-08

C4

3.3765405E-12

C5

-4.1070388E-16




2.25Cr-1Mo

3Cr-1Mo

5Cr-0.5Mo

5Cr-0.5Mo-Si

Parameter



800-1200

C0

1.6116223E+01

C1

-2.2988479E-02

C2

2.1835770E-05

C3

-1.2833734E-08

C4

4.2012778E-12

C5

-5.8449546E-16


800-1200

C0

1.1607134E+01

C1

-8.5353735E-03

C2

2.3722609E-06

C3

0

C4

0

C5

0


800-1200

C0

1.1770651E+01

C1

-8.8389784E-03

C2

2.5108933E-06

C3

0

C4

0

C5

0


800-1200

C0

1.1770651E+01

C1

-8.8389784E-03

C2

2.5108933E-06

C3

0

C4

0

C5

0


47



7Cr-0.5Mo

9Cr-1Mo

9Cr-1Mo-V

Type 304LS

48

Parameter



900-1200

C0

1.4536269E+01

C1

-1.0232458E-02

C2

2.7034326E-06

C3

0

C4

0

C5

0


900-1300

C0

4.04893689E+01

C1

-4.58475585E-02

C2

1.52674903E-05

C3

-1.35165711E-09

C4

0

C5

0


900-1300

C0

3.1524887E+03

C1

-1.4781109E+01

C2

2.7852967E-02

C3

-2.6205892E-05

C4

1.2291955E-08

C5

-2.2995921E-12


900-1500

C0

3.8310366E+01

C1

- 7.6035759E-02

C2

8.5397605E-05

C3

- 5.5768707E-08

C4

1.9173301E-11

C5

-2.7104077E-15




Type 304/304H SS

Type 316L SS

Type 316/316H SS

Type 317L SS

Parameter



1000-1500

C0

1.3035950E+01

C1

-8.3130608E-03

C2

1.9505879E-06

C3

0

C4

0

C5

0

Temperature Range

900-1500

C0

3.1313017E+01

C1

-5.3186547E-02

C2

5.3079687E-05

C3

-3.3897226E-08

C4

1.2195544E-11

C5

-1.9272376E-15


1000-1500

C0

1.2629907E+01

C1

-8.0541256E-03

C2

1.8898310E-06

C3

0

C4

0

C5

0


900-1500

C0

3.1313017E+01

C1

-5.3186547E-02

C2

5.3079687E-05

C3

-3.3897226E-08

C4

1.2195544E-11

C5

-1.9272376E-15


49



Type 321 SS

Type 321H SS

Type 347 SS

Type 347H SS

50

Parameter



900-1500

C0

1.645017E+01

C1

- 1.766063E-02

C2

8.225988E-06

C3

-1.612134E-09

C4

0

C5

0


1000-1500

C0

1.5128673E+01

C1

-1.0738718E-02

C2

2.0390552E-06

C3

0

C4

0

C5

0


900-1500

C0

1.105274E+01

C1

4.019553E-02

C2

-6.916989E-05

C3

2.599652E-08

C4

0

C5

0


900-1500

C0

2.6091589E+02

C1

- 1.0769332E+00

C2

1.9246050E-03

C3

- 1.7559313E-06

C4

7.9665773E-10

C5

-1.4196157E-13




Alloy 800

Alloy 800H

Alloy 800HT

HK-40

Parameter



900-1500

C0

1.4784080E+01

C1

-1.8623974E-02

C2

1.4953835E-05

C3

-7.2413632E-09

C4

1.9220365E-12

C5

-2.1442147E-16


1100-1650

C0

6.9797821E+00

C1

2.5834678E-03

C2

-2.4115193E-06

C3

0

C4

0

C5

0


900-1850

C0

1.5182940E+01

C1

-1.5959900E-02

C2

9.6990330E-06

C3

-3.1060390E-09

C4

4.0509520E-13

C5

0


1400-1850

C0

1.4332073E+01

C1

-9.2105347E-03

C2

1.7274314E-06

C3

0

C4

0

C5

0

Note: The average and minimum Larson-Miller Parameter is computed using Equation (16) with the appropriate coefficients from this table.


51


Table 5 – Material Designation and Applicable ASTM Specifications Material

Applicable ASTM Specifications

Low Carbon Steel

A161, A192

Medium Carbon Steel C-0.5Mo

A161 T1, A209 T1 A335 P1

1.25Cr-0.5Mo

A213 T11, A335 P11, A200 T11

2.25Cr-1Mo

A213 T22, A335 P22, A200 T22

3Cr-1Mo

A213 T21, A335 P21, A200 T21

5Cr-0.5Mo

A213 T5, A335 P5, A200 T5

5Cr-0.5Mo-Si

A213 T5b, A335 P5b

7Cr-0.5Mo

A213 T7, A335 P7, A200 T7

9Cr-1Mo

A213 T9, A335 P9, A200 T9

9Cr-1Mo-V

52

A53 Grade B (seamless), A106 Grade B, A210 Grade A-1

A213 T91, A335 P91, A200 T91

Type 304L SS

A213 Type 304L, A271 Type 304L, A312 Type 304L, A 376 Type 304L

Type 304/304H SS

A213 Type 304, A271 Type 304, A312 Type 304, A 376 Type 304 A213 Type 304H, A271 Type 304H, A312 Type 304H, A 376 Type 304H

Type 316L SS

A213 Type 316L, A271 Type 316L, A312 Type 316L, A 376 Type 316L

Type 316/316H SS

A213 Type 316, A271 Type 316, A312 Type 316, A 376 Type 316 A213 Type 316H, A271 Type 316H, A312 Type 316H, A 376 Type 316H

Type 317L SS

A213 Type 317L, A312 Type 317L

Type 321 SS

A213 Type 321, A271 Type 321, A312 Type 321, A 376 Type 321

Type 321H SS

A213 Type 321H, A271 Type 321H, A312 Type 321H, A 376 Type 321H

Type 347 SS

A213 Type 347, A271 Type 347, A312 Type 347, A 376 Type 347

Type 347H SS

A213 Type 347H, A271 Type 347H, A312 Type 347H, A 376 Type 347H

Alloy 800

B407 UNS N08800

Alloy 800H

B407 UNS N08810

Alloy 800HT

B407 UNS N08811

HK-40

A608 Grade HK-40



13

TECHNICAL BASIS

13.1 Overview

For each of the materials included in this document, the following four graphs are provided. a) Yield and ultimate tensile strength as a function of temperature. Values for the yield and ultimate tensile strength as a function of temperature are based on new test results above room temperature and are anchored to the specified minimum yield and ultimate tensile strength properties at room temperature. The new values shown are compared to the elevated temperature values given for the yield and ultimate tensile strength in RP530/ISO 13704, Revision 6. Note the elevated temperature values in RP530/ISO 13704, Revision 6 are anchored at 300°F or 400°F depending on the material. b) The average and minimum stress rupture strengths as functions of the Larson-Miller Parameter. The proposed relationship between rupture stress for minimum and the average materials are presented using optimized Larson-Miller Parameter constants based on recent analysis of material properties for virgin materials. The new parameter curves are shown and compared to the curves given in RP530/ISO 13704, Revision 6. Note that presentation using separate curves for average and minimum properties follows the presentation of stress rupture design curves in RP530/ISO 13704, Revision 6 where separate curves for average and minimum properties are provided for use with a single Larson-Miller constant that depends on the class of material, usually 15 or 20. For the new plots when using the average and minimum curves for computations, the optimized average LarsonMiller Constant from Table 3 is used to adjust all the lines so they may be compared. The test results used to calculate the proposed curves are shown on these plots. Again they are calculated using the optimized average constant in each case. Properties for service-exposed materials were not included at the specific directive of the API committee which cited the historical use of only virgin (unexposed) material in assembling the property data base. Thus, the Larson-Miller Parameter equations and constants provided herein are not the identical to those for the same materials as presented in API 579-1/ASME FFS-1 on fitness-for-service. Equations presented for use in determining fitness-for-service of service-exposed materials were established by testing materials as near as possible to design level stresses and temperatures with an emphasis on identifying creep strain rates and a creep damage parameter referred to as Omega, see API 579-1/ASME FFS-1, for the properties developed under service conditions. Changes in materials during service affect both the time-dependent and time-independent properties, identified in item a) above, of these materials. Additionally, the materials properties for the MPC Omega Method found in API 579-1/ASME FFS-1 were not intended to and do not represent material behavior at stresses and temperatures outside the range of design conditions. c) Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. A single curve is provided for the relationship between stress and Larson-Miller parameter. The differentiation between minimum and average time-dependent properties is accounted for by using the respective Larson-Miller Constants shown on each plot; Cmin to calculate the minimum properties and Cavg to calculate average properties. d) Rupture Exponent versus Temperature A plot of rupture exponent versus temperature is provided for each material. The rupture exponent is the slope of the (log) time vs. (log) rupture stress relation at a particular time specified by API. For most materials then, this plot is a shows a slope changing with temperature and usually decreasing with increasing temperature (decreasing stress). This is expected if a Larsen-Miller parameter is used for correlating data since absolute temperature appears in the denominator of the terms in the slope defining equation. However, the microstructures of some of the alloys vary with temperature and the ruptureexponent may increase or decrease with increasing temperature. The same may be true of ductility. To capture this variable relation between creep rate and ductility second or third order polynomials are needed to describe the shape of the parameter plot. The rupture exponent then may be a second order polynomial which may show inflections, minima (or even a maxima) in the range of interest. The microstructure /temperature changes that lead to an inflection in the rupture exponent curves at the time specified by API can be seen in the plots for Type 347 SS, Type 347H SS, Alloy 800H and Alloy 800 HT. There is nothing in nature to preclude that possibility.


53


13.2 Low Carbon Steel

The data base compiled was limited to tubular components and the typical low tensile strengths associated with normal heat treatments. For this study test results at very high stresses were eliminated to avoid imposing unfounded curvature on predicted low stress behavior. The resulting database was well fit by a linear expression, but the scatter is undeniable. The current use of a Larson Miller constant of 20 in API 530, Revision 6 in comparison to the appropriate value in the range of 17-19 results in too high design stresses when test results are extrapolated to typical carbon steel operating temperatures.

100

S T R E S S 10 , PROPOSED TENSILE STRENGTH PROPOSED YIELD STRENGTH

K s i

EXISTING RP 530 TENSILE EXISTING RP 530 YIELD

1 0

200

400

600

800

1000

TEMPERATURE, F

Figure 13.2-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: Low Carbon Steel

54



100 PROPOSED AVERAGE PROPOSED MINIMUM

S T R E S S 10 ,

EXISTING RP 530 AVERAGE EXISTING RP 530 MINIMUM RUPTURE DATA

K s i

1 26

28

30

32

34

36

LARSON‐MILLER PARAMETER/1000

Figure 13.2-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: Low Carbon Steel


55


100

Cavg = 17.70 Cmin= 18.15

S T R E S S 10 , K s i

1 26

28

30

32

34

36


Figure 13.2-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: Low Carbon Steel

56



9.00

RUPTURE EXPONENT, n

8.00

7.00

6.00

5.00

4.00

3.00 700

750

800

850

900

950

1000

TEMPERATURE, F

Figure 13.2-4: Rupture Exponent as a Function of Temperature: Low Carbon Steel


57


13.3 Medium Carbon Steel

As with low carbon materials the Larson Miller constant is well below 20 and results in more conservative stresses at expected operating temperatures as compared to the current document. The data used in the analysis was mostly from overseas sources for tubular products. Within this data set a clear beneficial effect of molybdenum on strength is seen at levels of only 0.005, 0.01 and 0.02% Mo. Data on heats with higher Mo content was typically eliminated because of its strong biasing effect.

100


K s i


1 0

200

400

600

800

1000

TEMPERATURE, F

Figure 13.3-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: Medium Carbon Steel

58




S T R E S S 10 ,


K s i

1 20

22

24

26

28

30

32


Figure 13.3-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: Medium Carbon Steel


59


100

Cavg = 15.15 Cmin= 15.6


1 20

22

24

26

28

30

32


Figure 13.3-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: Medium Carbon Steel

60



9.00

RUPTURE EXPONENT, n

8.00

7.00

6.00

5.00

4.00

3.00 700

750

800

850

900

950

1000

TEMPERATURE, F

Figure 13.3-4: Rupture Exponent as a Function of Temperature: Medium Carbon Steel


61


13.4 C-0.5Mo

Data for the very high stresses at which this strong alloy can be tested were eliminated because, absent data at low, realistic design level stresses, the polynomial fit would tend to show an inflection and nonconservative strength values at design levels. The resulting design lines from this analysis do not differ much from the current API 530 values. However, there is very little foundation for the design stresses at temperatures much above 950 F.

100


K s i


1 0

200

400

600

800

1000

1200

TEMPERATURE, F

Figure 13.4-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: C-0.5Mo

62




S T R E S S 10 ,


K s i

1 30

32

34

36

38

40


Figure 13.4-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: C-0.5Mo


63


100

Cavg = 18.72537 Cmin= 19.007756


1 30

32

34

36

38

40


Figure 13.4-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: C-0.5Mo

64



4.60 4.40

RUPTURE EXPONENT, n

4.20 4.00 3.80 3.60 3.40 3.20 3.00 700

750

800

850

900

950

1000

1050

TEMPERATURE, F

Figure 13.4-4: Rupture Exponent as a Function of Temperature: C-0.5Mo


65


13.5 1.25Cr-0.5Mo

Most prior curves in API 530 were taken from Smith's work for MPC in the 60's and 70's. For this material new data were obtained primarily from Japan. The superior behavior predicted at low stresses is based on MPC's Project Omega studies in which the material did not suffer from severe oxidation in tests at temperatures used in the low stress range. The trends are demonstrated by the equations and coefficients found in Annex F of API 579-1/ASME FFS-1. These validate the more linear curve shape for these low alloy steels.

100


K s i


1 0

200

400

600

800

1000

1200

TEMPERATURE, F

Figure 13.5-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: 1.25Cr-0.5Mo

66




S T R E S S 10 ,


K s i

1 34

36

38

40

42

44


Figure 13.5-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: 1.25Cr-0.5Mo


67


100

Cavg = 21.387 Cmin= 21.891803


1 34

36

38

40

42

44


Figure 13.5-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: 1.25Cr-0.5Mo

68



7.00

RUPTURE EXPONENT, n

6.50

6.00

5.50

5.00

4.50

4.00 800

850

900

950

1000

1050

1100

1150

1200

TEMPERATURE, F

Figure 13.5-4: Rupture Exponent as a Function of Temperature: 1.25Cr-0.5Mo


69


13.6 2.25Cr-1Mo

Most prior curves in API 530 were taken from Smith's work for MPC in the 60's and 70's. New data were obtained primarily from Japan. The superior behavior predicted at low stresses is based on MPC's Project Omega studies, in which the tested material did not suffer from severe oxidation in tests at temperatures used in the low stress range. The trends are demonstrated by the equations and coefficients found in Annex F of API 579-1/ASME FFS-1. These validate the more linear curve shape for these low alloy steels.

100


K s i


1 0

200

400

600

800

1000

1200

TEMPERATURE, F

Figure 13.6-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: 2.25Cr-1Mo

70




S T R E S S 10 ,


K s i

1 30

32

34

36

38

40


Figure 13.6-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: 2.25Cr-1Mo


71


100

Cavg = 18.9181 Cmin= 19.565607


1 30

32

34

36

38

40


Figure 13.6-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: 2.25Cr-1Mo

72



7.00

RUPTURE EXPONENT, n

6.50

6.00

5.50

5.00

4.50 800

850

900

950

1000

1050

1100

1150

1200

TEMPERATURE, F

Figure 13.6-4: Rupture Exponent as a Function of Temperature: 2.25Cr-1Mo


73


13.7 3Cr-1Mo

The 3 Cr-1Mo alloy is not widely used and very little test data of any type, new or old, is available. It is believed that there is a continuum of behavior from annealed 2 ¼ Cr-1Mo to the 5 Cr alloys. The sparse stress rupture data was inadequate, on its own for analysis. Combining the available data with new data for the 5 Cr alloy tubes showed the lower Cr alloy be slightly stronger as expected because of richer Mo and lower Cr. MPC software permits identifying the behavior of the 3Cr-1Mo in the general population. The average and minimum values represent that unique subset. No new tensile data were available. The current API trend was adopted but indexed to the specified minimum properties. This resulted in slightly lower curves when the curve was ratioed to those specified values.

100


K s i


1 0

200

400

600

800

1000

1200

TEMPERATURE, F

Figure 13.7-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: 3Cr-1Mo

74




S T R E S S 10 ,


K s i

1 24

26

28

30

32

34


Figure 13.7-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: 3Cr-1Mo


75


100

Cavg = 15.38106 Cmin= 15.785226


1 24

26

28

30

32

34


Figure 13.7-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: 3Cr-1Mo

76



6.50 6.30

RUPTURE EXPONENT, n

6.10 5.90 5.70 5.50 5.30 5.10 4.90 4.70 4.50 800

850

900

950

1000

1050

1100

1150

1200

TEMPERATURE, F

Figure 13.7-4: Rupture Exponent as a Function of Temperature: 3Cr-1Mo


77


13.8 5Cr-0.5Mo

A large amount of data on 5Cr-0.5Mo tubes was obtained from overseas sources. The stress rupture database exceeded 500 test results, many lasting many years. Tensile data were also obtained but there was significant scatter, especially at higher temperatures. Over 20 heats were evaluated with good agreement with the current lines.

100


K s i


1 0

200

400

600

800

1000

1200

TEMPERATURE, F

Figure 13.8-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: 5Cr-0.5Mo

78




S T R E S S 10 ,


K s i

1 24

26

28

30

32

34


Figure 13.8-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: 5Cr-0.5Mo


79


100

Cavg = 15.58928 Cmin= 16.025829


1 24

26

28

30

32

34


Figure 13.8-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: 5Cr-0.5Mo

80



6.50 6.30

RUPTURE EXPONENT, n

6.10 5.90 5.70 5.50 5.30 5.10 4.90 4.70 4.50 800

850

900

950

1000

1050

1100

1150

1200

TEMPERATURE, F

Figure 13.8-4: Rupture Exponent as a Function of Temperature: 5Cr-0.5Mo


81


13.9 5Cr-0.5Mo-Si

There are no new data sources for 5Cr-0.5Mo-Si. Therefore, the material parameters developed for 5Cr0.5Mo are used to develop the following plots.

100


K s i


1 0

200

400

600

800

1000

1200

TEMPERATURE, F

Figure 13.9-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: 5Cr-0.5Mo-Si

82




S T R E S S 10 ,


K s i

1 24

26

28

30

32

34


Figure 13.9-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: 5Cr-0.5Mo-Si


83


100

Cavg = 15.58928 Cmin= 16.025829


1 24

26

28

30

32

34


Figure 13.9-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: 5Cr-0.5Mo-Si

84



6.50 6.30

RUPTURE EXPONENT, n

6.10 5.90 5.70 5.50 5.30 5.10 4.90 4.70 4.50 800

850

900

950

1000

1050

1100

1150

1200

TEMPERATURE, F

Figure 13.9-4: Rupture Exponent as a Function of Temperature: 5Cr-0.5Mo-1Si


85


13.10 7Cr-0.5Mo

This alloy is seldom specified and has been deleted from several current ASTM specifications. Little data could be found in the literature and the data were not considered statistically meaningful or suitable for generating new curves. The plots shown are based on the previous API 530 curves for the alloy converted to the format used in this document. They are not intended to represent any change in the properties anticipated.

100


K s i


1 0

200

400

600

800

1000

1200

TEMPERATURE, F

Figure 13.10-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: 7Cr-0.5Mo

86




S T R E S S 10 ,


K s i

1 34

36

38

40

42

44


Figure 13.10-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter Miller – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: 7Cr-0.5Mo


87


100

Cavg = 19.62055 Cmin= 20.43746


1 34

36

38

40

42

44


Figure 13.10-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: 7Cr-0.5Mo

88



8.00 7.80

RUPTURE EXPONENT, n

7.60 7.40 7.20 7.00 6.80 6.60 6.40 6.20 6.00 900

950

1000

1050

1100

1150

1200

TEMPERATURE, F

Figure 13.10-4: Rupture Exponent as a Function of Temperature: 7Cr-0.5Mo


89


13.11 9Cr-1Mo

The data base compiled was confined to tubes produced overseas for heat exchangers as opposed to the original database of domestic products that produced an unusually wide scatter band. The relatively good oxidation resistance of the alloy permitted tests to very low stresses and a normal scatter band was obtained from this analysis. Most of the data tracked API’s mean line but the resulting minimum (design) lines are higher than the current lines at most temperatures. A second order polynomial was selected to provide conservatism for extrapolation beyond the range of available data.

100


K s i


1 0

200

400

600

800

1000

1200

1400

TEMPERATURE, F

Figure 13.11-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: 9Cr-1Mo

90




S T R E S S 10 ,


K s i

1 42

44

46

48

50

52

54


Figure 13.11-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: 9Cr-1Mo


91


100

Cavg = 25.85909 Cmin= 26.223587


1 42

44

46

48

50

52

54


Figure 13.11-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: 9Cr-1Mo

92



11.00 10.00

RUPTURE EXPONENT, n

9.00 8.00 7.00 6.00 5.00 4.00 3.00 900

950

1000

1050

1100

1150

1200

1250

1300

TEMPERATURE, F

Figure 13.6-4: Rupture Exponent as a Function of Temperature: 9Cr-1Mo


93


13.12 9Cr-1Mo-0.25V

For this material new data were obtained primarily from Japan.

100


K s i


1 0

200

400

600

800

1000

1200

1400

TEMPERATURE, F

Figure 13.12-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: 9Cr-1Mo-0.25V

94




S T R E S S 10 ,


K s i

1 52

54

56

58

60

62


Figure 13.12-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: 9Cr-1Mo-0.25V


95


100

Cavg = 30.36423 Cmin= 30.886006


1 52

54

56

58

60

62


Figure 13.12-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: 9Cr-1Mo-0.25V

96



15.00

RUPTURE EXPONENT, n

13.00

11.00

9.00

7.00

5.00

3.00 900

950

1000

1050

1100

1150

1200

1250

1300

TEMPERATURE, F

Figure 13.12-4: Rupture Exponent as a Function of Temperature: 9Cr-1Mo-0.25V


97


13.13 Type 304L Stainless Steel

Type 304L Stainless Steel – Very little rupture testing of 304L is intentionally carried out. MPC studied many heats and found 304 produced with carbon content in the range of 0.04%. These were used as the basis for estimating performance at the L grade level.

100


PROPOSED TENSILE STRENGTH

PROPOSED YIELD STRENGTH

1 0

250

500

750

1000

1250

1500

TEMPERATURE, F

Figure 13.13-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: Type 304L Stainless Steel

98




S T R E S S 10 ,


K s i

1 32

34

36

38

40

42


Figure 13.13-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: Type 304L Stainless Steel


99


100

Cavg = 17.55 Cmin= 18.287902


1 32

34

36

38

40

42


Figure 13.13-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: Type 304L Stainless Steel

100



9.50 9.00

RUPTURE EXPONENT, n

8.50 8.00 7.50 7.00 6.50 6.00 5.50 5.00 4.50 900

950

1000

1050

1100

1150

1200

1250

1300

1350

1400

1450

1500

TEMPERATURE, F

Figure 13.13-4: Rupture Exponent as a Function of Temperature: Type 304L Stainless Steel


101


13.14 Type 304 & 304H Stainless Steel

Data was obtained from overseas sources. Only data on tubes were utilized since the data were adequate for analysis. A total of 28 heats where studied of different manufacturing process and producers. More than 450 results were included in the final data base. Materials could not be separated and so 304 and 304H were lumped together. The resulting scatter band was less than the current curves but the minimum was about the same.

100


K s i


1 0

250

500

750

1000

1250

1500

TEMPERATURE, F

Figure 13.14-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: Type 304 & Type 304H Stainless Steel

102




S T R E S S 10 ,


K s i

1 28

30

32

34

36

38

40


Figure 13.14-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: Type 304 & Type 304H Stainless Steel


103


100

Cavg = 15.52195 Cmin= 16.145903


1 30

32

34

36

38

40

42

44

46


Figure 13.14-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: Type 304 & Type 304H Stainless Steel

104



7.00

RUPTURE EXPONENT, n

6.50

6.00

5.50

5.00

4.50 1000

1050

1100

1150

1200

1250

1300

1350

1400

1450

1500

TEMPERATURE, F

Figure 13.14-4: Rupture Exponent as a Function of Temperature: Type 304 & Type 304H Stainless Steel


105



Data analysis was performed on Type 316L to develop the Type 317L parameters, see paragraph 12.16. In addition, the data indicates that the differences in the yield and ultimate tensile strength trend curves are indistinguishable. Therefore, the material parameters developed for Type 317L are used for Type 316L.

100


K s i


1 0

250

500

750

1000

1250

1500

TEMPERATURE, F


106




S T R E S S 10 ,


K s i

1 28

30

32

34

36

38

40


Figure 13.15-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: Type 316L Stainless Steel


107


100

Cavg = 15.2 Cmin= 15.740107


1 28

30

32

34

36

38

40


Figure 13.15-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: Type 316L Stainless Steel

108



9.50

RUPTURE EXPONENT, n

8.50

7.50

6.50

5.50

4.50

3.50 900

950

1000

1050

1100

1150

1200

1250

1300

1350

1400

1450

1500

TEMPERATURE, F

Figure 13.15-4: Rupture Exponent as a Function of Temperature: Type 316L Stainless Steel


109


13.16 Type 316 & 316H Stainless Steel

Over 700 data points were included in the final set, mainly on tubular products. Other product forms were included to obtain results at over 1500F (low stresses). The data were all from foreign sources. The tensile trends were remarkably similar to the current trends, when the different room temperature index values were considered. Some heats showed poor stress rupture behavior. These aspects are being studied further. However, the design values are very similar to those used now where the curves are supported by data.

100


K s i


1 0

250

500

750

1000

1250

1500

TEMPERATURE, F

Figure 13.16-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: Type 316 & Type 316H Stainless Steel

110




S T R E S S 10 ,


K s i

1 30

32

34

36

38

40

42


Figure 13.16-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: Type 316 & Type 316H Stainless Steel


111


100

Cavg = 16.30987 Cmin= 16.764145


1 30

32

34

36

38

40

42

44


Figure 13.16-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: Type 316 & Type 316H Stainless Steel

112



6.50 6.30

RUPTURE EXPONENTENT, n

6.10 5.90 5.70 5.50 5.30 5.10 4.90 4.70 4.50 1000

1050

1100

1150

1200

1250

1300

1350

1400

1450

1500

TEMPERATURE, F

Figure 13.16-4: Rupture Exponent as a Function of Temperature: Type 316 & Type 316H Stainless Steel


113



There are very little data available on Type 317L. Thus far only a few test results were found, some were incomplete and relatively short. However, a database of modern low carbon Type 316 was compiled from Japan. This is far larger than anything Smith had to work with. MPC heat centered procedures enable indexing on the limited 317L data and adjusting to provide a better estimate of low carbon material performance. These heats should have increased nitrogen levels.

100




1 0

250

500

750

1000

1250

1500

TEMPERATURE, F


114




S T R E S S 10 ,


K s i

1 28

30

32

34

36

38

40


Figure 13.17-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant (Using Type 316L Data): Type 317L Stainless Steel


115



S T R E S S 10 ,


K s i

1 28

30

32

34

36

38

40


Figure 13.17-3: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant (Showing Type 317L Data Points Relative to Type 316L Parameter Equations): Type 317L Stainless Steel

116



100

Cavg = 15.2 Cmin= 15.740107


1 28

30

32

34

36

38

40


Figure 13.17-4: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: Type 317L Stainless Steel (Using Type 316L Data)


117


9.50

RUPTURE EXPONENT, n

8.50

7.50

6.50

5.50

4.50

3.50 900

950

1000

1050

1100

1150

1200

1250

1300

1350

1400

1450

1500

TEMPERATURE, F

Figure 13.17-5: Rupture Exponent as a Function of Temperature: Type 317L Stainless Steel (Using Type 316L Date)

118



13.18 Type 321 Stainless Steel

Only 321 tube data conforming to modern specifications, but not classified as 321H by the foreign suppliers was used. The average stress rupture strength found is in reasonable agreement with Smith's original analyses for MPC that provided the values used by API 530 for this material. However, the variance was much smaller in the current work. It is believed that Smith included products that did not conform to today's specifications. Therefore the minimum strength is a more reasonable (higher) fraction of the average. Failure to assure proper heat treatment and composition can lead to unsatisfactory performance.

100


K s i


1 0

250

500

750

1000

1250

1500

TEMPERATURE, F

Figure 13.18-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: Type 321 Stainless Steel


119



S T R E S S 10 ,


K s i

1 24

26

28

30

32

34


Figure 13.18-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: Type 321 Stainless Steel

120



100

Cavg = 13.325 Cmin= 12.8


1 24

26

28

30

32

34

36


Figure 13.18-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: Type 321 Stainless Steel


121


6.25

RUPTURE EXPONENT, n

5.75 5.25 4.75 4.25 3.75 3.25 2.75 900

950

1000

1050

1100

1150

1200

1250

1300

1350

1400

1450

1500

TEMPERATURE, F

Figure 13.18-4: Rupture Exponent as a Function of Temperature: Type 321 Stainless Steel

122



13.19 Type 321H Stainless Steel

The data collection focused on tubular products. The yield strength data found were scattered, as is often the case for products heat treated to high temperatures, rapidly cooled and then straightened. Statistical analysis of yield strengths revealed a weak temperature correlation, best described by a straight line. The stress rupture data displayed less scatter than the API 530 plot for this alloy probably because of greater attention to conformance of the materials to the H grade requirements. The average behavior was substantially unchanged, but the minimum was elevated. Most data were obtained for material produced by modern processes in Japan.

100


K s i


1 0

250

500

750

1000

1250

1500

TEMPERATURE, F

Figure 13.19-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: Type 321H Stainless Steel


123



S T R E S S 10 ,


K s i

1 28

30

32

34

36

38


Figure 13.19-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: Type 321H Stainless Steel

124



100

Cavg = 14.75958 Cmin= 15.293986


1 28

30

32

34

36

38

40


Figure 13.19-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: Type 321H Stainless Steel


125


6.50

RUPTURE EXPONENT, n

6.00 5.50 5.00 4.50 4.00 3.50 1000

1050

1100

1150

1200

1250

1300

1350

1400

1450

1500

TEMPERATURE, F

Figure 13.19-4: Rupture Exponent as a Function of Temperature: Type 321H Stainless Steel

126



13.20 Type 347 Stainless Steel

For this material new data were obtained primarily from Japan. The trends are demonstrated by the equations and coefficients found in Annex F of API 579-1/ASME FFS-1.

100


K s i


1 0

250

500

750

1000

1250

1500

TEMPERATURE, F

Figure 13.20-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: Type 347 Stainless Steel


127



S T R E S S 10 ,


K s i

1 26

28

30

32

34

36

38


Figure 13.20-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: Type 347 Stainless Steel

128



100

Cavg = 14.25 Cmin= 14.889042


1 26

28

30

32

34

36

38


Figure 13.20-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: Type 347 Stainless Steel


129


11.00 10.00

RUPTURE EXPONENT, n

9.00 8.00 7.00 6.00 5.00 4.00 3.00 900

950

1000

1050

1100

1150

1200

1250

1300

1350

1400

1450

1500

TEMPERATURE, F

Figure 13.20-4: Rupture Exponent as a Function of Temperature: Type 347 Stainless Steel

130



13.21 Type 347H Stainless Steel

For this material new data were obtained primarily from Japan. The trends are demonstrated by the equations and coefficients found in Annex F of API 579-1/ASME FFS-1.

100

S T R E S S ,

10 PROPOSED TENSILE STRENGTH PROPOSED YIELD STRENGTH

K s i


1 0

250

500

750 1000 TEMPERATURE, F

1250

1500

Figure 13.21-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: Type 347H Stainless Steel


131



S T R E S S 10 ,


K s i

1 26

28

30

32

34

36


Figure 13.21-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: Type 347H Stainless Steel

132



100

Cavg = 13.79341 Cmin= 14.458025


1 26

28

30

32

34

36

38

40


Figure 13.21-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: Type 347H Stainless Steel


133


9.50 9.00 8.50 RUPTURE EXPONENT, n

8.00 7.50 7.00 6.50 6.00 5.50 5.00 4.50 4.00 3.50 900

950

1000

1050

1100

1150

1200

1250

1300

1350

1400

1450

1500

TEMPERATURE, F

Figure 13.21-4: Rupture Exponent as a Function of Temperature: Type 347H Stainless Steel

134



13.22 Alloy 800

The data chosen for this class of material excluded results from heats that do not take advantage of the heat treating and compositional controls imposed to obtain the 800H and 800HT grades. These include controls on aluminum, titanium, and carbon contents, grain size and annealing temperatures. Such unrestricted material is not usually used for creep service and the data base is relatively small. The very high temperatures permitted for 800H and 800HT cannot be recommended with confidence.

100




1 0

250

500

750

1000

1250

1500

1750

TEMPERATURE, F

Figure 13.22-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: UNS N08800 (Alloy 800)


135


100 PROPOSED AVERAGE PROPOSED MINIMUM EXISTING RP 530 AVERAGE

S T R E S S 10 ,

EXISTING RP 530 MINIMUM RUPTURE DATA

K s i

1 28

30

32

34

36

38


Figure 13.22-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: UNS N08800 (Alloy 800)

136



100

Cavg = 16.50878 Cmin= 17.005384


1 28

30

32

34

36

38

40

42

44


Figure 13.22-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: UNS N08800 (Alloy 800)


137


6.00 5.80

RUPTURE EXPONENT, n

5.60 5.40 5.20 5.00 4.80 4.60 4.40 4.20 4.00 900

950

1000

1050

1100

1150

1200

1250

1300

1350

1400

1450

1500

TEMPERATURE, F

Figure 13.22-4: Rupture Exponent as a Function of Temperature: UNS N08800 (Alloy 800)

138



13.23 Alloy 800H

Yield and ultimate tensile strength data were obtained for tubular products of Alloy 800H. The stress rupture data shown represent a broad international database generally in conformance with prior estimates. Some of the test results captured here are from tests lasting in excess of 100,000 hours.

100




1 0

250

500

750

1000

1250

1500

1750

TEMPERATURE, F

Figure 13.23-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: UNS N08810 (Alloy 800H)


139



S T R E S S 10 ,


K s i

1 30

32

34

36

38

40

42

44

46


Figure 13.23-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: UNS N08810 (Alloy 800H)

140



100

Cavg = 16.04227 Cmin= 16.564046


1 30

32

34

36

38

40

42

44

46


Figure 13.23-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: UNS N08810 (Alloy 800H)


141


7.00

RUPTURE EXPONENT, n

6.50

6.00

5.50

5.00

4.50 1100

1150

1200

1250

1300

1350

1400

1450

1500

1550

1600

1650

TEMPERATURE, F

Figure 13.23-4: Rupture Exponent as a Function of Temperature: UNS N08810 (Alloy 800H)

142



13.24 Alloy 800HT

MPC combined the original database used in setting the control limits that defined the 800HT class of material with more recent data on tubular products from overseas sources. Some results on the newer products were for tests that lasted beyond 30,000 hours at low stresses and very high temperatures. As a result the parameter curve is well defined. It should be noted that the improvement for 800HT versus 800H is not expected to be very large at intermediate temperatures and disappears at very high temperatures due to the redissolving of carbides and strengthening nickel-aluminum-titanium compounds.

100




1 0

250

500

750

1000

1250

1500

1750

TEMPERATURE, F

Figure 13.24-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: UNS N08811 (Alloy 800HT)


143



S T R E S S 10 ,


K s i

1 28

30

32

34

36

38

40


Figure 13.24-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: UNS N08811 (Alloy 800HT)

144



100

Cavg = 13.2341 Cmin= 13.606722


1 28

30

32

34

36

38

40


Figure 13.24-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: UNS N08811 (Alloy 800HT)


145


7.25

RUPTURE EXPONENT, n

6.75 6.25 5.75 5.25 4.75 4.25 3.75 900

995

1090

1185

1280

1375

1470

1565

1660

1755

1850

TEMPERATURE, F

Figure 13.24-4: Rupture Exponent as a Function of Temperature: UNS N08811 (Alloy 800HT)

146



13.25 HK-40

Elevated temperature yield and ultimate tensile strength values were obtained for the high carbon content HK 40 castings. The strength properties found varied, but the trend shown was strongly indicative of an increase in yield strength in the 1200-1300˚F range due to precipitation at those temperatures. The extent of the increase in yield strength is not easily displayed by the smooth curve of the polynomial used to display the properties. The large database collected shows lower minimums than the existing API 530 curves.

100




1 0

250

500

750

1000

1250

1500

1750

TEMPERATURE, F

Figure 13.25-1: Yield and Ultimate Tensile Strength as a Function of Temperature – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units: HK-40


147



S T R E S S 10 ,


K s i

1 26

28

30

32

34

36


Figure 13.25-2: The Average and Minimum Stress Rupture Strengths as Functions of the LarsonMiller Parameter – Comparison of Existing RP530 Data and Proposed New Data in US Customary Units Based on the Average Larson-Miller Constant: HK-40

148



100

Cavg = 10.4899 Cmin= 10.856489

S T R 10 E S S , K s i

1

0.1 22

24

26

28

30

32

34

36


Figure 13.25-3: Design Curve Showing the Larson-Miller Parameter as a Function of Stress in US Customary Units. The Minimum Larson-Miller Constant (Cmin) is used to Calculate Minimum TimeDependent Properties and the Average Larson-Miller Constant (Cavg) is used to Calculate Average Time-Dependent Properties: HK-40


149


5.00 4.80

RUPTURE EXPONENT, n

4.60 4.40 4.20 4.00 3.80 3.60 3.40 3.20 3.00 1400

1450

1500

1550

1600

1650

1700

1750

1800

TEMPERATURE, F

Figure 13.25-4: Rupture Exponent as a Function of Temperature: HK-40

150


1850

WRC_541

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