01-SAMSS-332

Materials System Specification 01-SAMSS-332

3 July 2007

High Frequency Welded Line Pipe, Class B Materials and Corrosion Control Standards Committee Members Anezi, Mohammed Ali, Chairman Rumaih, Abdullah Mohammad, Vice Chairman Abdul Hadi, Abdul Latif Ibrahim Bannai, Nabeel Saad Buraiki, Iyad Abdulrazzak Burgess, Brian Wayne Cruz, Czar Ivan Tecson Kermad, Abdelhak Lobley, Graham Russel Mehdi, Mauyed Sahib Moore, Mark Andrew Mugbel, Wajdi Mohammad Nasri, Nadhir Ibrahim Niemeyer, Dennis Charles Nuaim, Tareq Abdulaziz Omari, Ahmad Saleh Rao, Sanyasi Tems, Robin Douglas

Saudi Aramco DeskTop Standards Table of Contents

1 2 3 4 5

Scope.................... Scope.................................. ........................... .......................... ............... 2 Normative References................ References..... ...................... ................... ........ 3 Definitions........... Definitions........................... ............................. .......................... ............... 4 Classification and Designation................ Designation..... .................. ....... 4 Information to be Supplied by the Purchaser................. Purchaser...... ....................... ................... ....... 4 6 Manufacturing........ Manufacturing...................... ............................ .......................... ............ 5 7 Requirements......... Requirements...................... ........................... ........................... ............. 8 8 Inspection............ Inspection............................ ............................. .......................... ............. 9 9 Marking of the Pipes................. Pipes....... ...................... .................... ........ 15 10 Coating for Temporary Protection............... Protection..... ............ 15 Previous Issue: 30 March 2005

Next Planned Update: 1 April 2010 Page 1 of 24

Primary contact: Anezi, Mohammed Ali on 966-3-8746122 Copyright©Saudi Aramco 2007 200 7. All rights reserved.

Document Responsibility: Materials and Corrosion Control Issue Date: 3 July 2007 Next Planned Update: 1 April 2010

01-SAMSS-332 High Frequency Welded Line Pipe, Class B

Table of Contents (Cont'd)

Annex B - Manufacturing Procedure Qualification......... Qualification...................... .......................... ................... ...... Annex B.3 - Qualification of Welding Conditions.............. Conditions..... .................... ................ ..... Annex D - Non-Destructive Testing (NDT)......... Annex F - Statistical Process Control.................

16 18 21 22

Introduction Conflicts and Deviations

1)

Any conflicts between this Specification and other applicable Saudi Aramco Engineering Procedures (SAEPs), Saudi Aramco Engineering Standards (SAESs), Saudi Aramco Materials System Specifications (SAMSSs), Saudi Aramco Standard Drawings (SASDs), or industry standards, codes, and forms shall be resolved in writing by the Company or Buyer Representative through the Manager, Consulting Services Department of Saudi Aramco, Dhahran.

2)

Direct all requests to deviate from this Specification in writing to the Company or Buyer Representative, who shall follow internal company procedure SAEP-302 and forward such requests to the Manager, Consulting Services Department of Saudi Aramco, Dhahran.

The following paragraph numbers refer to International Standard ISO 3183-2, which is a part of this specification. The text in each paragraph below is an addition to ISO 3183-2 unless it is noted as a modification. modification. ISO 3183-2 paragraphs that are not listed below are adopted without modification.

1

Scope [Modification] This Specification only applies to high frequency welded (HFW) pipe, outside diameter 114.3 mm (NPS 4) and larger, for use in Saudi Aramco Requirement Class B. Commentary Note: Requirement Class B services are defined by Saudi Aramco Engineering Standards (i.e., SAES-L-136 ) and typically include sweet and sour liquid hydrocarbons and dry sweet hydrocarbon gas transportation.

Unless stated to the contrary in the purchase requisition and the purchase order, pipe manufactured to this specification must be suitable for external coating with fusion bonded epoxy at a later date by the Purchaser. If the pipe will be internally coated, it shall be so stated in the purchase requisition and the purchase order. Page 2 of 24


2


Normative References The following additional references apply to the implementation of this specification: 2.1

Saudi Aramco References Saudi Aramco Engineering Procedure SAEP-302

Instructions for Obtaining a Waiver of a Mandatory Saudi Aramco Engineering Requirement

Saudi Aramco Engineering Standard SAES-L-136

Pipe Selection and Restrictions

Saudi Aramco Materials System Specifications 01-SAMSS-016

Qualification of Pipeline and Pressure Vessel Steels for Resistance to Hydrogen-Induced Cracking

01-SAMSS-022

Fracture Control Testing Procedures for Line Pipe

01-SAMSS-024

Pipe Handling and Nesting

Saudi Aramco Inspection Requirements Form 175-010300

2.2

Pipe: Plain End Electric Resistance or Electric Induction Welded Steel Pipe

Industry Codes and Standards American National Standard Institute ANSI/ASQC Z1.4

Sampling Procedures and Tables for Inspection by Attributes

American Petroleum Institute API SPEC 5L

Specification for Line Pipe

American Society for Testing and Materials ASTM E112

Estimating the Average Grain Size of Metals

ASTM E381

Standard Method of Macrotech Testing Steel Bars, Billets, Blooms, and Forgings

Page 3 of 24



International Organization for Standardization ISO 3183-2

ISO 8258 ISO 9764

ISO 11496

3

Petroleum and Natural Gas Industries - Steel Pipe for Pipelines - Technical Delivery Conditions Part 2: Pipes of Requirement Class B Shewhart Control Charts Electric Resistance and Induction Welded Tubes for Pressure Purposes - Ultrasonic Testing of the Weld Seam for the Detection of Longitudinal Imperfections Seamless and Welded Steel Tubes for Pressure Purposes - Ultrasonic Testing of Tube Ends for the Detection of Laminar Imperfections

Definitions 3.2.8

Continuous Electronic Process Control (CEPC), Level 2 For the purpose of this specification, CEPC, if used, shall be a minimum of Level 2, hereby defined as continuous monitoring and recording of heat input variables (voltage, current, line speed) and seam annealing variables (annealing power input and line speed) with alarm and automatic pipe marking for upset conditions outside of the qualified process limits (See Annex B.3, Figure 8). In addition, it is highly desirable to extend CEPC to monitor squeeze roll force or another variable directly related to metal distortion angle (see Figure 7).

4

Classification and Designation [No Modifications]

5

Information to be Supplied by the Purchaser 5.1

Mandatory information [modification] 8)

5.2

Impact requirements are per 01-SAMSS-022 Class I or Class IV. For Class IV, impact energy value is specified in the purchase order.

Other information •

Applicable Saudi Aramco Materials System Specifications (SAMSS)

•

Service, including "sour" or "non-sour"

•

If pipe must be suitable for internal coating, it shall be so stated.

Page 4 of 24


6


Manufacturing 6.1

General

6.1.1

The quality system shall be subject to approval by Saudi Aramco Inspection Department/Vendor Inspection Division when the manufacturer is surveyed for consideration as a qualified supplier and the quality system shall be assessed periodically thereafter.

6.1.2

NDT personnel shall be qualified to ISO 11484 Level 2 or ASNT SNT-TC1A Level 2. The primary Level 3 employee shall be certified in accordance with ASNT CP-189.

6.1.3

A manufacturer, not previously qualified to bid on this specification, shall submit at least one complete Manufacturing Procedure (see Annex B) for approval prior to award of any Purchase Order and the manufacturer and bid shall not be considered technically acceptable until approved as described in Annex B. Once qualified, a manufacturer may qualify additional procedures after award of the Purchase Order(s), as described below. A specific manufacturing procedure shall be qualified for the job (see Annex B). A procedure must be qualified and approved for each set of essential variables (see B.0 and B.3.) Minor exceptions to this specification may be addressed in the Manufacturing Procedure approval process (Annex B). In these cases, formal waivers are not required, but intended exceptions and Saudi Aramco approval must be in writing. Major deviations from this specification shall be submitted in writing to the Company or Buyer Representative, who shall follow internal company procedure SAEP-302 and forward such requests to the Manager, Consulting Services Department of Saudi Aramco, Dhahran. A postproduction report shall be submitted to the Company or Buyer Representative demonstrating adequate process control during the entire production run for the purchase order. Commentary Note: The postproduction report shall include complete production test data such as SPC charts, hardness, flattening tests, load cell readings, anneal width, etc.

6.2.1

For sour service, the steel shall be treated by calcium addition for sulfide inclusion shape control. See also paragraph 7.2.1.

Page 5 of 24


6.3


Pipe manufacturing This specification applies to HFW pipe only. [modification] Strip shall be rolled from continuously cast slabs that are no less than 100 mm in thickness as cast. Slit strip shall not be used unless the Manufacturing Procedure documents that the strip is capable of meeting the C2; R2; S2 rating after macroetching with ammonium persulfate in accordance with ASTM E381, or an equivalent procedure approved by Saudi Aramco. Such slit strip (regardless of service) shall also be capable of passing sour service testing in accordance with 01-SAMSS-016 using Solution A. Process Control, Option 1 Verifiable control of process variables is required for all pipe produced. The welding process shall also be qualified prior to production, in accordance with this specification. Basic process control requirements for welding are: 1.

Qualify the process limits in accordance with Annex B.3.

2.

During production, verify maintenance of acceptable welding conditions and adequate process control. Either of three methods is acceptable for use: a.

Continuous Electronic Process Control (CEPC), Level 2. (see 3.2.8). For every pipe length, heat input variables (voltage, current, line speed) and seam annealing variables (annealing temperature and line speed) shall be continuously monitored and shown to be within the qualified process limits (See Figure 8) by electronic data acquisition. Metal distortion angle shall be verified metallographically in accordance with 8.2.3.7.2. If squeeze roll force or another parameter proven to have direct correlation with flow angle is measured as part of CEPC, then the metal distortion angle shall be measured metallographically at least once per shift. CEPC methods shall not require Statistical Sampling and Statistical Process Control (SPC) methods for control of voltage, current, line speed, and metal distortion angle. CEPC shall immediately identify and segregate individual pipe lengths whose qualified process limits (Annex B.3) have been compromised.

b.

Statistical Process Control (SPC)

Page 6 of 24



If CEPC methods are not used, physical sampling for SPC of all process variables is required. In this case, the manufacturer shall submit his proposed SPC procedure for approval along with the Manufacturing Procedure (Annex B and Annex B.2). Annex F contains guidelines for an SPC procedure that would be satisfactory to Saudi Aramco. SPC methods shall identify and segregate each lot that may contain pipe manufactured with process variables outside of the qualified process limits (Figure 8 and Annex B.3) in accordance with ISO 8258 using control limits specified in Annex B.3.5. c.

Combination of CEPC and SPC If CEPC is used to control heat input process variables, but not metal distortion angle, SPC can be used to control metal distortion angle in accordance with the frequency described in 8.2.3.7.2. The average of the tests required for each lot shall represent one sub-group to be charted by SPC in accordance with ISO 8258 using control limits as specified in Annex B.3.5.

3.

Qualification of welding conditions shall verify that the primary power line voltage to the mill, and within the mill, does not fluctuate significantly. The mill must demonstrate and assure maintenance of adequate weld power control.

Process Control, Option 2 Verifiable control of process variables is required for all pipe produced. A manufacturer may submit its own proprietary process control procedures for review. The information shall be treated as confidential by Saudi Aramco. The proprietary process control system must meet the intent of this specification to define relevant process variables, relate these variables to production of acceptable pipe, and maintain process control during production. Deviations from Option 1 requirements (above) must be very well supported with detailed procedure descriptions, a large amount of production data, and appropriate statistical analysis. 6.4

Heat treatment condition The full width and thickness of the weld seam shall be heat treated after welding so that the weld microstructure and hardness requirements in paragraph 8.2.3.7.2 are met. Full body normalizing is optional. CEPC, Level 2, when employed shall be used to assure the ID heat treat width and centering by monitoring annealing temperature and line speed as related to temperature control. In the absence of CEPC, SPC shall be used for the Page 7 of 24



sample frequency described in 8.2.3.7.2. Failure or abnormal operation of the seam heat treatment equipment shall trigger an alarm and automatic pipe marking. Failure to control the ID heat treat width, and centering, by SPC shall cause the lot in question to be rejected.

7

Requirements 7.2

Chemical composition [modification]

7.2.1

Cast analysis (heat analysis) Element

7.2.2

7.3

Maximum %

Silicon

0.35

Manganese

1.40 (Table 3 note applies)

Sulfur (sour service)

0.003

Sulfur (non-sour service)

0.006

Copper

0.20 if 01-SAMSS-016 specified

Calcium

0.006

Ca/S (sour service)

>

1.5 when S

>

0.0015%

Product analysis (see ISO 3183-2 Table 3, Note 4) Wall thickness, mm

Maximum CEV

< 11.1

0.42

11.1 – 12.6

0.41

12.7 – 15.8

0.40

> 15.8

0.39

Mechanical and technological properties [modification] Table 6 and 7 are not applicable. Fracture control testing shall be in accordance with 01-SAMSS-022.

7.5

Surface conditions, imperfections and defects Pipe that is to be externally and/or internally coated shall be free of scabs, slivers, laps, seams, and other conditions that would impair coating, including, but not limited to, oil, grease, tape, lacquer, and varnish.

7.6

Dimensions, masses, and tolerances

7.6.3.3

Length

Page 8 of 24


7.6.3.3.2

8


Random length group "r2" shall be delivered except as specified below or otherwise specified in the Purchase Order. 1)

No pipe lengths less than 10.0 m will be accepted.

2)

Pipe lengths less than 11.6 m can not exceed 2% of the total line item quantity.

3)

If the pipe is identified in the Purchase Order as being intended for subsequent internal coating, the maximum length of any individual pipe is 12.8 m.

Inspection 8.1

Types of inspection and inspection documents Saudi Aramco Inspection Requirements Form 175-010300 specifies the inspection and testing requirements. The certificates/data to be provided are of the ISO 10474 Type 3.1.B and shall be reported in the English language.

8.2

Specific inspection and testing

8.2.1

Type and frequency of tests For certain environments, such as wet, sour crude oil, the Purchase Order may specify 01-SAMSS-016, which contains the Saudi Aramco requirements for hydrogen induced cracking (HIC) testing.

8.2.2

Selection and preparation of samples and test pieces

8.2.2.2.3

Charpy V-notch impact test pieces [modification] 01-SAMSS-022 applies. Full size specimens (10 mm x 10 mm) shall be use whenever possible and the pipe sample may be flattened before machining to obtain as close as possible to a full size specimen. Subsize specimens shall only be allowed when the pipe wall thickness is insufficient to provide full size specimens. In these cases the largest possible subsize specimens, obtainable by flattening or use of tapered ends, shall be used.

8.2.3.6

Flattening test

8.2.3.6.1

[modification] Besides the two test pieces taken from both end-of-coil locations, one test piece shall also be taken from two random, but not identical, locations

Page 9 of 24



through the remaining length of the coil and tested with the weld at the 3 o'clock position. Commentary Note: One coil may produce 12-34 pipe lengths depending on size and thickness. The intent is to get 4 tests evenly spaced throughout the coil length. Ideally, 4 separate pipes in the coil length are to be sampled.

8.2.3.6.2

[modification] In the first step of the flattening test, no weld opening shall occur when the pipe is flattened as follows, and continue flattening to report the height when a weld opening does occur or until opposite walls of the pipe meet:

where,

D/t

H/D

>50

0.4

30-50

0.5

<30

0.6

D = specified outside diameter t

=

H =

specified wall thickness distance between flattening plates

All values in the same unit. 8.2.3.7

Macrographic and metallographic examinations

8.2.3.7.2

Weld microstructure and hardness tests Frequency: One test per 100 lengths if CEPC, Level 2, is in effect for controlling all process variables and seam heat treating. If CEPC, Level 2, is not in place for metal distortion angle control or seam heat treating, there shall be four lengths tested per 100 lengths produced. If no CEPC is in effect for controlling any process variables or seam heat treating, tests shall be taken in accordance with Annex F. At least one pipe from each cast (heat) shall be tested. Preparation: For each pipe tested, at least one transverse specimen of the weld area shall be polished to metallographic quality and shall be etched to provide grain boundary contrast. Acceptance criteria: Using a metallurgical microscope or metallograph, the transverse specimen shall be examined at a magnification sufficient to easily measure grain size per ASTM E112. Page 10 of 24



a)

The normalized zone shall extend through the wall and completely overlap the original weld line.

b)

The weld seam microstructure shall contain no untempered martensite, or bainite, and no inclusions at the fusion line.

c)

The grain sizes of the weld seam area and the parent metal shall be determined per ASTM E112. Weld seam grain size shall not exceed parent metal grain size by more than two ASTM grain-size units.

d)

A balanced uniform forged structure shall be present as depicted in Figure 7a and Figure 7b.

e)

Fusion line must be perpendicular with the pipe surfaces to within ± 5° (A) for any pipe wall greater than 7.9 mm (0.312 in.) and ± 10° for pipe with wall thickness equal to or less than 7.9 mm (0.312 in.).

f)

The distortion angle Θ of the metal flow due to squeeze roll forging pressure must be within the qualified limits (Annex B.3, Figure 8), as measured with respect to the pipe wall centerline (B 1 & B2), perpendicular to the fusion line. The distortion angle shall be determined (four locations) near a position equivalent to one-fourth wall thickness (¼ x wt) and three-fourths wall thickness (¾ x wt) from the O.D. surface on both sides of the weld seam. During qualification and production of a particular line item (same grade, O.D., w.t.), the OD and ID distortion angles shall always be measured at the same distance (L) from the fusion centerline, as established during qualification for average OD and ID metal distortion angles. The location of L for angle measurement shall be at the outer region of the welding heat tint zone, with a tolerance of ± 3% of the wall thickness. The distance L OD for the OD angles ΘOD may be different from the distance LID for the ID angles ΘID, but each shall be given in the qualification report.

Page 11 of 24



Figure 7a Commentary Note: Figure 1 through Figure 6 are in the base specification, ISO 3183-2.

Figure 7b B1 - Angle of metal flow distortion (Theta in Figure 7a) on OD side B2 - Angle of metal flow distortion on ID side A

- Angle of fusion line measured from perpendicular to OD surface

WT - Pipe wall thickness Note: Various techniques can be used for revealing and measuring metal flow distortion. Some methods that have proven successful individually or in combination include: 1) saturated picric acid etchant in distilled water, 2) take specimens from a small pipe sample in which the seam has not been heat treated, 3) use of an optical comparator or profile projector.

Hardness Tests

Frequency and sample preparation for hardness tests shall be as described in 8.2.3.7.2 above. The same samples can be used for both the weld Page 12 of 24



microstructure tests and the hardness tests. Vickers hardness testers shall be used. Hardness traverses shall be made 1.5 mm ± 0.5 mm from the I.D. and O.D. surfaces and at the mid-wall. Each traverse shall consist of at least the following: one indentation in the center of the weld area, one indentation located not more than 1.0 mm on each side of the central indentation, and one indentation in the parent metal outside of the normalized zone on each side of the weld. (Total of 5 indentations in each traverse.) For each traverse, the middle three measurements should be in the normalized zone and encompass the weld seam. The maximum hardness measured shall not exceed 240 HV (Vickers Hardness using a 10 kg load) and the average hardness of the middle three I.D. measurements shall not exceed the average hardness of the corresponding three O.D. measurements as shown by a statistical test of data from two samples with unequal variances for a 95% confidence level. 8.2.3.8

Hydrostatic test The seam shall be positioned in the upper quadrant (approximately 12:00 o'clock) prior to the application of pressure. Any pipe whose seam is not in the upper quadrant during pressure testing shall be re-tested. At least one inspection observer shall be present during pressurizing to observe the weld seam, from a safe location, for leaks that may not register an obvious pressure drop on the test gauge. Any failing or leaking pipes shall be rejected and the cause investigated and corrective actions documented. The lighting in the hydrostatic test area and the area for visual examination shall provide a minimum illumination of 500 lux (modification).

8.2.4

Retests, sorting and reprocessing (modification) Paragraph 9 of ISO 404 does not apply. The following retest criteria apply to rejects due to welding outside the qualified process limits (Annex B.3, Figure 8): a.

Single pipes rejected while manufacturing to 6.3.2.a shall not be retested.

b.

Production lots rejected while manufacturing to 6.3.2.b may be retested in the following manner for the process variable in question. 1)

Test 13 additional pipe lengths from the lot rejected and perform all testing required by 8.2.3.6, and 8.2.3.7.

Page 13 of 24


c.


2)

For lots that were rejected for excessive or insufficient heat input: If all flattening and metallographic results, for the sample group of 13, are acceptable, accept the lot with no further processing. If the results are not acceptable, either reject the lot, finally, or test each remaining pipe in the lot and reject those lengths that exhibit unacceptable results. Those pipes exhibiting acceptable results form the remainder of the lot which shall be accepted.

3)

For lots that were rejected for excessive or inadequate metal distortion angle (see Annex B.3.5): If all flattening and metallographic results are acceptable for the retested pipes, accept the lot with no further processing. If metal distortion angle of the sample is still found unacceptable calculate the average OD and ID angles (X-bar 13) and the associated standard deviations (S13) for each. If either of the following calculations is false reject the lot, finally: a)

X 13

b)

12 × S132

−

μ × 3.606 S13

≤

2.179

2

σ ≤ 19 .68

Any production lot rejected while manufacturing to 6.3.2.c may be retested in the following manner. 1)

Test 13 additional pipe lengths from the lot rejected and perform all testing required by 8.2.3.6, and 8.2.3.7.

2)

Any single pipe rejected for unacceptable heat input shall not be retested.

3)

For lots that were rejected for excessive or inadequate metal distortion angle (see Annex B.3.5): If all flattening and metallographic results are acceptable for the retested pipes, accept the lot with no further processing. If metal distortion angle of the sample is still found unacceptable calculate the average OD and ID angles (X-bar 13) and the associated standard deviations (S13) for each. If either of the following calculations is false reject the lot, finally: a)

X 13

b)

12 × S132

−

μ × 3.606 S13

≤

2.179

2

σ ≤ 19.68

Page 14 of 24


9


Marking of the Pipes [Modification] Marking of pipes shall be in accordance with API SPEC 5L (2004) Section 10 with the additional requirements listed below. The marking "Spec. 3183-2" shall be used in place of "Spec. 5L" and the symbol "ERW" shall be substituted for the symbol "E" as the Process of Manufacture. The grade number shall first be that from API SPEC 5L followed by the equivalent grade, in parenthesis, from ISO 3183-2. The size of the lettering shall be commensurate with the diameter of the pipe, but in no case less than 25 mm in height for API standard markings and 13 mm in height for shipping markings. Paint stencil marks with white alkyd enamel or equivalent. Each pipe shall be marked with the port designation as well as the Purchase Order number and item number. Example:

Saudi Aramco/Dammam Saudi Aramco D-518-01-3000/Item No. 2

Each pipe shall be marked with the Saudi Aramco Material System (SAMS) Catalog designated stock number (SAP 9CAT number). For pipe purchased for which there is no assigned SAMS 9CAT stock number, the pipe shall be marked "01-SAMSS-332." For pipe that has been impact tested to 01-SAMSS-022, the class (Class I or Class IV) indicated on the Purchase Order shall be included in the markings. Example:

01-SAMSS-022 Class IV

Non-sour Pipe

Pipe designated in the Purchase Order as non-sour, and/or where 01-SAMSS-016 is not referenced in the Purchase Order, shall be identified by painting a white longitudinal stripe, approximately 50 mm wide by 450 mm long, on the inside surface of both ends. This stripe is intended to provide identification until the pipe is installed.

10

Coating for Temporary Protection Pipe shall be supplied without mill coating unless specified otherwise in the Purchase Order. Varnish coating of the markings is acceptable provided that the varnish is hard drying with a maximum dry film thickness of 0.050 mm.

30 March 2005 3 July 2007

Revision Summary Revised the Next Planned Update. Reaffirmed the contents of the document and reissued with minor changes. Editorial revision to delete Section 11.

Page 15 of 24



Annex B – Manufacturing Procedure Qualification B.0

Introductory Note (modified)

All pipe must be manufactured using a qualified Manufacturing Procedure that has been approved by Saudi Aramco Consulting Services Department/Materials Engineering & Corrosion Control Division (ME&CCD). Procedure submittals include B.1, B.2, and B.3 requirements. The Manufacturing Procedure shall be qualified prior to start of main production and submitted no later than five days after start of main production. Fax or email submittals are acceptable. Final acceptance of pipe is contingent upon successful qualification of a procedure and approval by ME&CCD, plus evidence that the pipe was manufactured within the limits of the Manufacturing Procedure. The manufacturer may use a previously qualified Manufacturing Procedure if the new product falls within a set of previously qualified essential variable groups listed below. In this case, the submittal should be in the form of a Manufacturing Procedure Specification with simplified B.1 information and without the detailed supporting test data that was previously submitted. The manufacturing procedure shall be requalified any time there is a change in the essential variables. If the essential welding variables (Annex B.3) change, but the essential manufacturing variables are unchanged, then only the welding conditions (Annex B.3) must be requalified. Essential manufacturing variables: a)

Pipe grade

b)

Outside diameter group

c)

d) B.1

1)

Up to and including 323.9 mm (NPS 12)

2)

Over 323.9 mm (NPS 12)

Wall thickness group 1)

6 mm to 11 mm

2)

Over 11 mm

Strip coils from same steelmaker/specification/grade.

Characteristics of the Manufacturing Process

In addition to the ISO 3183-2 Annex B.1 requirements, the manufacturer shall identify the primary steel producer, the reroller, if applicable, and the strip mill and shall state the thickness, and split width if applicable, of the slab from which Page 16 of 24



the strip was rolled and the method for controlling segregation during casting. In addition to the list of required information, the pipe making equipment should be described with particular attention to equipment and processes that may not meet the intent of this specification. Completely describe the strip edge milling, automatic seam tracking, and weld seam heat treatment process and equipment. B.2

Manufacturing Procedure Qualification Tests

Manufacturing procedure qualification test results to be submitted include: a)

All tests required in Section 8. A complete series of tests shall be performed on at least one pipe from each coil described in B.3.3.c. If multiple welding lines will be used for production the same requirements shall apply to each pipe manufacturing line.

b)

01-SAMSS-016 (HIC test) and 01-SAMSS-022 (impact test) results if applicable.

c)

Welding qualification as specified in Annex B.3, attached.

d)

For the purpose of the first-time qualification only (Para. 6.1.3) the submittal may be based upon Annex B.0, B.1, mill historical production data, and the mill's own process control procedures. However, the quantity and quality of the information submitted must be sufficient to confirm compliance with the intent of this specification. If a purchase order is awarded on this basis, the specific qualifications required by Annex B.2 and B.3 shall be submitted and approved prior to start of production.

e)

SPC Procedure if CEPC method is not employed for control of process variables. See Paragraph 6.3.2.b.

f)

SPC Procedure if CEPC method is used for control of only heat input process variables. See Paragraph 6.3.2.c.

g)

Description of CEPC, if employed. See paragraph 6.3.2.a.

h)

Postproduction Process Control Report (see 6.1.3) for a previous order, either a) the last order, or preferably b) the last order with the same essential welding variables (see Annex B.3).

Page 17 of 24



Annex B.3 – Qualification of Welding Conditions 1.

2.

3.

Essential welding variables: a.

Pipe grade

b.

Nominal diameter

c.

Specified wall thickness

d.

Operation within qualified process limits (Figure 8)

e.

Contact tip/roller alloy composition (HFERW only)

f.

Induction coil configuration (HFI only)

g.

Impeder configuration (HFI only)

±

1.0 mm

Process variables: a.

Heat Input Factor (function of wall thickness, voltage, current, temperature, and line speed)

b.

Metal Flow Factor (distortion angle ÷ girth reduction at squeeze roll)

c.

Seam annealing power (related to temperature)

d.

Seam anneal width at I.D. surface

Qualification Steps a.

Install chart recorders, or other appropriate devices, for electronic data acquisition to monitor and control the process heat input variables (Process variable #1 above).

b.

From the nominal settings for voltage, current, line speed, and metal flow factor (distortion angle ÷ girth reduction) identify, or calculate, the maximum and minimum limits for each and construct the preliminary process limits (see Figure 8). Note:

c.

the boundary limits may be based on experience (such as data from a previous order), or calculated, or chosen arbitrarily.

Produce at least one coil at the nominal welding conditions and one coil at each of the chosen maximum and minimum limit points, determined in B.3.3.b above, and depicted in Figure 8. i.

Sample each coil at the front, middle, and end.

Page 18 of 24



ii.

Evaluate each sample for compliance with 8.2.3.6 (flattening test) and 8.2.3.7 (metallographic examination).

iii.

If any set of specimens fails to meet the requirements above, adjust the variable settings accordingly and produce another coil. If necessary continue adjustments until the desired limits of the process have been identified.

iv.

Choose, at random, one additional pipe from coil A and remove at least 10 samples, at least one meter apart, for metallographic tests in accordance with 8.2.3.7.2.f.

Figure 8

4.

Figure 8, in terms of 6.3.2.a, represents the limits within which CEPC must control the processes.

5.

Perform the following calculations with the measurements made in 8.2.3.7.2.f for all five test coils. a)

Determine the average overall metal distortion angle for all OD angles combined. This calculated value is defined as X-bar QOD.

b)

Determine the standard deviation for all OD angles combined. This calculated value is defined as S QOD. If SQOD > 3.0, the process must be requalified after process improvements have been made.

Page 19 of 24


6.

7.


c)

Determine the average overall metal distortion angle for all ID angles combined. This calculated value is defined as X-bar QID.

d)

Determine the standard deviation for all ID angles combined. This calculated value is defined as S QID. If SQID > 3.0 the process must be requalified after process improvements have been made.

e)

Determine, for the additional single pipe from coil A, the average OD and ID angles with their associated standard deviations. These values (XbarAOD, X-barAID, SAOD, and SAID) are defined as approximations of the true process means and standard deviations and shall appear in the qualification report. If SAOD or SAID are greater than S QOD or SQID, respectively, requalification shall be required after significant process improvement.

The final process capability curve (Figure 8) represents the qualified process limits for the Manufacturing Procedure and combination of essential welding variables. Any operation shown to be outside of the Qualified Process Limits will require evaluation by CSD or requalification, and any pipe produced outside this qualified boundary must be either rejected or held for further evaluation. a)

For pipe manufactured with full CEPC, level 2, (see 6.3.2.a) the CEPC system shall control process variables within the area bounded in Figure 8 in accordance with 6.3.2.a.

b)

For pipe manufactured without any CEPC (see 6.3.2.b) adequate SPC sampling must be accomplished in accordance with Annex F to assure the maintenance of the Qualified Process Limits in Figure 8 with a 95% confidence level.

c)

For pipe manufactured to 6.3.2.c the distortion metal angle tests taken in accordance with 8.2.3.7.2 shall be SPC charted in accordance with ISO 8258. A production lot shall be rejected if the sub-group plot falls outside of the UCL or LCL.

The pipe used for qualification may be included in the production order provided that each coil is sampled and tested as described in B.3.3 above. Any coil that does not pass all of the tests shall be rejected.

Page 20 of 24



Annex D – Non-Destructive Testing (NDT) D.2

General NDT requirements and acceptance criteria D.2.2 Timing of NDT operations Ultrasonic examination of the weld seam shall be carried out after hydrostatic testing. Means shall be provided to mark the pipe when the ultrasonic inspection equipment indicates an imperfection is present so that defective areas can be identified. D.2.4 Laminar imperfections at the pipe ends Verification shall be carried out in accordance with ISO 11496. Also, the seam weld area of the bevels shall be examined by dye penetrant, magnetic particle, or shear wave ultrasonic inspection; the choice of inspection techniques is at the mill's option. No laminations or cracklike indications extending into the face of the bevel are acceptable. If any defects are found at the pipe ends, the pipe shall be cut back to remove such defects.

D.4

NDT of HFW pipe D.4.1 Nondestructive testing of the weld seam D.4.1.1

Pipe for liquid service shall be inspected to ISO 9764 acceptance Level L3 (N10 notch) and pipe for gas service shall be inspected to acceptance Level L2 (N5 notch).

D.4.2 Laminar imperfections in the pipe body Verification of compliance shall be carried out. Inspection may be on the flat form prior to welding or full-body inspection after welding, at the discretion of the manufacturer.

Page 21 of 24



Annex F – Statistical Process Control of Heat Input Variables SAMPLING:

Establish a physical sampling plan for each lot of 100 lengths in accordance with ANSI/ASQC Z1.4 and the table below using an AQL of 0.65. Sample Size Normal

20

Tightened

32

Reduced

8

Lot Reject no.

1

STATISTICAL PROCESS CONTROL (SPC) METHODS: 1.

When CEPC methods are not used, follow the sampling plan for metallurgical structure and record the appropriate welding conditions representing voltage, current, line speed, and if possible squeeze roll pressure or other value related to metal distortion angle.

2.

Construct SPC charts in accordance with ISO 8258 for appropriate values representing Process Variables as identified in Annex B.3.2, " Qualification of Welding Conditions. "

3.

Monitor and maintain process control of essential process variables, with SPC charts described above in accordance with ISO 8258.

4.

Any single sample group, or process variable, represented by one value plotted outside of the constructed Upper and Lower Control Limits (UCL and LCL) shall be rejected and evaluated for a possible assignable cause. Corrective action shall be implemented, where appropriate, and associated lot(s) rejected.

5.

Any two consecutive sample sub-groups represented by two consecutive values plotted outside of the constructed UCL and LCL shall be identified for assignable cause. Associated lots shall be rejected and production halted until effective corrective action has been achieved.

STATISTICAL PROCESS CONTROL OF METALLURGICAL STRUCTURE: 6.

Sampling Plan for manufacturing without CEPC methods. The sampling plan is not required for any other testing required by this specification unless required by 6.3, 6.4 or 8.2.3.7.2.

Page 22 of 24



a.

The sampling plan required for metallurgical control is to be used after steady state production conditions have been achieved or verified. Steady state conditions are defined as changes in process variable settings that are still within the qualified process limits in Annex B.3, Figure 8.

b.

All pipes produced during non-steady state production conditions must be rejected, evaluated if appropriate for metal distortion angle, and the results, including process control chart recordings, reported to Saudi Aramco Consulting Services Department, Materials Engineering & Corrosion Control Division for decision as to disposition.

c.

The following sampling plan for metallurgical control is based upon ANSI/ASQC Z1.4, "Sampling Procedures and Tables for Inspection by Attributes".

d.

i)

Lot size, for process control, shall consist of 100 pipe lengths in any single pipe diameter / wall thickness / strength combination. Lot sizes of less than 100 pipe lengths shall be evaluated either the same as 100 pipe lengths, or added to the previous lot and the larger lot evaluated in accordance with Z1.4.

ii)

Sampling plans are selected for an AQL = 0.65. Refer to Z1.4 switching rules when appropriate for switching from normal inspection to either tightened or reduced inspection activity (Figure 9).

Attempt to sample non-sequential pipe lengths from each lot of 100. Evaluate the weld zone microstructure, or values representing such, in terms of the requirements in 8.2.3.7.2 of this document, and reject the lot if one specimen or sub-group fails.

7.

Rejected lots shall be re-inspected (8.2.4) by UT, metallographic section, mechanical testing, and re-hydrotested if appropriate. The results of process control for each rejected lot shall be reported to Saudi Aramco for disposition.

8.

Any product, by normal inspection, that results in the rejection of two out of five consecutive lots of pipe will require major mechanical maintenance, related to control of the essential variables, and switched to tightened inspection (see Figure 9 and the table above). Pipe production, under tightened inspection, that results in the rejection of ten sequential lots, shall require a halt in production, major mechanical and/or electrical maintenance, re-qualification of related welding conditions, and all ten lots produced shall require re-evaluation for an assignable cause for losing process control.

Page 23 of 24


9.


Any product, by normal inspection, that results in the acceptance of 10 consecutive lots shall allow switching to reduced inspection (see Figure 9 and the table above).

Figure 9 – Statistical Process Control Cycle

Page 24 of 24

01-SAMSS-332

Recommend Documents