45-SAMSS-013

Materials System Specification 45-SAMSS-013 12 December 2006 High Frequency Welded Solid Expandable Tubulars (SET) Drilling & Workover Wellhead & Valves Standards Committee Members Smith, Stephen Wayland, Chairman Turki, Said Issa, Vice Chairman Abouelnaaj, Khaled Khater Akroosh, Fahad Ahmad Alwan, Waseem Mohammed Cole, Edward L Shiha, Saad Mohammed Tissan, Abdul Rahman Mousaid

Saudi Aramco DeskTop Standards Table of Contents 1 2 3 4 5 6 7 8 9 10 11 12 13

Scope............................................................. 2 Conflicts and Deviations................................ 2 References..................................................... 2 Definitions...................................................... 3 Information to be Supplied by the Purchaser.................................... 4 Process of Manufacture................................. 4 Material Requirements................................... 8 Dimensions, Weights, Lengths, Defects and End Finishes...................... 8 Threading....................................................... 8 Inspection and Testing................................... 8 Marking of the Pipes..................................... 14 Coating and Protection ................................ 14 Packaging for Shipment and Storage.......... 14

Annex A – Manufacturing Procedure Qualification.......................................... 15 Annex B – Non-Destructive Testing (NDT)........ 20 Annex C – Statistical Process Control of Heat Input Variables......................... 21 Previous Issue: New

Next Planned Update: 12 December 2011 Page 1 of 23

Primary contact: Smith, Stephen Wayland on 966-3-8628060 Copyright©Saudi Aramco 2006. All rights reserved.

Document Responsibility: Drilling & Workover Wellhead & Valves Issue Date: 12 December 2006 Next Planned Update: 12 December 2011

1

45-SAMSS-013 High Frequency Welded Solid Expandable Tubulars (SET)

Scope This SAMSS applies to the Manufacture of Solid Expandable Tubulars (SET), with an outside diameter of 3-½ inches (88.9 mm) and larger operating at a temperature above 80oC.

2

3

Conflicts and Deviations 2.1

Any conflicts between these process control requirements 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, Drilling Engineering Department of Saudi Aramco, Dhahran.

2.2

Direct all requests to deviate from these process control requirements in writing to the Company or Buyer Representative, who shall follow internal company procedure SAEP-302 and forward such requests to the Manager, Drilling Engineering Department of Saudi Aramco, Dhahran.

2.3

Resolution to conflicting requirements between these process control requirements, purchase order or national standards, the manufacturer's specifications or drawings, and deviations to these process control requirements, purchase order or national standards, not specifically covered as an exception to the purchase order, shall be approved by the Responsible Standardization Agent. The supplier shall also advise the buyer's Inspection Representative in writing of all conflicts and deviations and their approval.

References The following additional references apply to the implementation of this specification addendum: 3.1

Saudi Aramco References Saudi Aramco Engineering Procedure SAEP-302

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

Saudi Aramco Inspection Requirements Form 175-450900

Pipe: High Frequency Welded Solid Expandable Tubulars Page 2 of 23


3.2


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

Sampling Procedures and Tables for Inspection by Attributes

American Standard Nondestructive Testing ASNT CP-189

Qualification and Certification of Nondestructive Testing Personnel

ASNT TC-1A

Recommended Practice, Personnel Qualification and Certification Nondestructive Testing

American Petroleum Institute API SPEC 5CT

Specification for Casing and Tubing

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

International Organization for Standardization

4

ISO 3183-2

Petroleum and Natural Gas Industries - Steel Pipe for Pipelines - Technical Delivery Conditions

ISO 8258

Shewhart Control Charts

Definitions 4.1

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, control, and recording of heat input variables (voltage, current, line speed, squeeze roll pressure) and seam annealing variables (annealing temperature and line speed) with alarm or tracking of joint and automatic pipe marking for conditions outside of the qualified process limits (See Annex A.3, Figure 2). If full body normalizing is employed CEPC shall include time at soaking temperature, furnace zone or induction zone temperatures, as applicable, and furnace or line speed. In addition, it is highly desirable to extend CEPC to monitor and control squeeze roll force or another variable directly related to metal distortion angle (see Figure 1A & 1B).

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4.2


Upper Control Limit The statistical upper control limit of a statistical process control chart calculated as the process mean plus one half of three times the standard deviation of the sample or population. See ASQC Z1.4.

4.3

Lower Control Limit The statistical lower control limit of a statistical process control chart calculated as the process mean minus one half of three times the standard deviation of the sample or population. See ASQC Z1.4.

4.4

Acceptable Quality Limit The maximum percent of non-conforming product that, for the purpose of sampling inspection, can be considered satisfactory as a process average.

4.5

Supplier For the purpose of this specification the supplier shall be considered the provider of goods and/or services for SET installations.

5

Information to be Supplied by the Purchaser 5.1

Casing For SET, minimum impact energy value shall be 50 ft-lb for base metal longitudinal and 33 ft-lb for base metal and ERW seam transverse for any single values for 5 mm x 10 mm specimen (half size) @ -4°F.

5.2

Other Information Qualification and Production spreadsheet program (Supplied by CSD).

6

Process of Manufacture 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 authorized to accept product, shall be qualified to ISO 11484 Level 2 or ASNT SNT-TC-1A Level 2. The primary Level 3 employee shall be certified in accordance with ASNT CP-189. Page 4 of 23



6.1.3 A manufacturer, not previously qualified to bid on this specification addendum, shall submit at least one complete Manufacturing Procedure (see Annex A) for approval by Saudi Aramco Drilling Engineering Department with the assistance of Consulting Services Department, Materials Engineering & Corrosion Control Division prior to award of any Purchase Order and the manufacturer and bid shall not be considered technically acceptable until approved as described in Annex A. Once qualified, a manufacturer may qualify additional procedures after award of the Purchase Order(s), as described below.

6.1.4

6.1.3.1

A specific manufacturing procedure shall be qualified for the job (see Annex A). A procedure must be qualified and approved for each set of essential variables (see A and A.3.)

6.1.3.2

Minor exceptions to this specification addendum may be addressed in the Manufacturing Procedure approval process (Annex A). In these cases, formal waivers are not required, but intended exceptions and Saudi Aramco, DED approval must be in writing.

6.1.3.3

Major deviations from this specification addendum 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, Drilling Engineering Department of Saudi Aramco, Dhahran.

6.1.3.4

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.

Pipe Manufacturing This specification applies to HFW pipe only. Strip shall be rolled from continuously cast slabs that are no less than 100 mm in thickness as cast. Slit slabs or 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. Commentary Note: There will be a maximum of one slit per slab or strip.

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6.1.5


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 addendum. Basic process control requirements for welding are: 6.1.5.1

Qualify the process limits in accordance with Annex A.

6.1.5.2

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

Continuous Electronic Process Control (CEPC), Level 2. (See 4.1) 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 Annex A.3, Figure 2) by electronic data acquisition. Metal distortion angle shall be verified metallographically in accordance with 10.6.3.4. 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 A) have been compromised.

b)

Statistical Process Control (SPC) 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 A). Annex C 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 2 and Page 6 of 23



Annex A) in accordance with ISO 8258 using control limits specified in Annex A. c)

Combination of CEPC and SPC If CEPC is used to control welding 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 10.6.3.4. If CEPC is used to control seam annealing temperature and line speed, SPC can be used to control ID normalizing width with the frequency described in 10.6.3.4. 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 A.

6.1.5.3

6.1.6

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 addendum 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.

6.2

Heat Treat 6.2.1

Weld Seam Heat Treatment The full width and thickness of the weld seam shall be heat treated after welding so that the weld microstructure and hardness requirements in paragraphs 10.6.3.4 and 10.4 are respectfully met. Full body normalizing is optional as in 6.2.2.

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6.2.2


Full Body Normalizing At the option of the manufacturer full body normalizing may be used to promote optimal microstructure in the body and weld seam.

7

Material Requirements Chemical Requirements Product analysis (see API 5CT, Table 2 except as modified below).

8

Element

Maximum %

Silicon

0.35

Sulfur

0.005

Phosphorus

0.020

Calcium

0.006

Dimensions, Weights, Lengths, Defects and End Finishes Length as specified in purchase order.

9

Threading Pin and box threads shall be machined and inspected as per the manufacturer's written procedures.

10

Inspection and Testing Types of inspection and inspection documents Saudi Aramco Inspection Requirements Form 175-450900 specify 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. 10.1

Frequency of Testing Tensile tests, flattening tests, hardness tests, impact tests, and metallographic evaluation will be conducted at a minimum of one (1) of each test per 20 joints of finished pipe unless otherwise specified in 10.2 through 10.6 below. Hydrostatic testing (see 10.7) is to be carried out on each joint.

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10.2

Tensile Test

Yield Strength Tensile Strength Yield/Tensile Elongation Reduction of Area

10.3


Min 70ksi ----------20% ------

Target 80 ksi -----.75 25%

Max 95 ksi Report Only .90 -----Report Only

Flattening Test Two test pieces taken from both end-of-coil locations, two additional test pieces shall be taken from each of two random, but not identical, locations through the remaining length of the coil and tested with the weld at the 3 o'clock position. The flattening tests shall be performed either after weld seam heat treatment, or full body normalizing. Flattening shall be performed once again after any final heat treatment (for example: quench and temper). 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: D/t

H/D

>50 30-50 <30

0.4 0.5 0.6

D = specified outside diameter t = specified wall thickness H = distance between flattening plates All values in the same unit. 10.4

Hardness Tests Frequency and sample preparation for hardness tests after final heat treat shall be as described in API 5CT for L80 grade except that the maximum hardness shall be HRB 100 max.

10.5

Impact Test API 5CT applies. Half-size specimens (5 mm x 10 mm) shall be used. The pipe sample may be flattened before machining if required and shall be reported as such. The frequency shall be as per 10.5.2.7.1. Page 9 of 23


10.6


Location

Orientation

Requirement (@ -4°F)

Body

(LVN)

50 ft lbs single value min.

Body

(TVN)


Weld

(TVN)


Metallographic Evaluation, Weld Microstructure 10.6.1

10.6.2

Frequency 10.6.1.1

One test per 20 lengths if CEPC, Level 2, is in effect for controlling all welding process variables (voltage, current, line speed, metal distortion angle). If squeeze roll force is controlled, the test frequency shall be one test per 100 lengths.

10.6.1.2

If no CEPC is in effect for controlling any welding process variables or seam heat treating process variables, tests shall be taken in accordance with Annex C. 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 and forging flow line contrast.

10.6.3

Acceptance Criteria: 10.6.3.1

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

10.6.3.2

A balanced uniform forged structure shall be present as depicted in Figures 1A and 1B.

10.6.3.3

Fusion line must be perpendicular with the pipe surfaces to within ± 5° 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.).

10.6.3.4

The distortion angle Θ of the metal flow due to squeeze roll forging pressure must be within the qualified limits (Annex A.3, Figure 2), as measured with respect to the pipe wall centerline (B1 & B2), perpendicular to the fusion line. The distortion angle shall be determined (four locations) near a Page 10 of 23



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 LOD 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.

Figure 1A

Figure 1B B1 -Angle of metal flow distortion (Theta in Figure 1A) on OD side

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B2 -Angle of metal flow distortion on ID side A -Angle of fusion line measured from perpendicular to OD surface WT -Pipe wall thickness Commentary Note: Various techniques can be used for revealing and measuring metal flow distortion. Some methods that have proven successful individually or in combination include:

10.7

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.

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).

10.8

Retests, Sorting and Reprocessing The following retest criteria apply to rejects due to welding outside the qualified process limits (Annex A.3, Figure 2), or after evaluating the statistical history of quantities of pipe produced: 10.8.1

Single pipes rejected while manufacturing to 6.1.5.2(a) shall not be retested.

10.8.2.

Production lots rejected while manufacturing to 6.1.5.2(b) may be retested in the following manner for the process variable in question. 10.8.2.1

Test 13 additional pipe lengths from the lot rejected and perform all testing required by 10.3 and 10.6.

10.8.2.2

For lots that were rejected for excessive or insufficient welding: If all flattening and metallographic results, for the Page 12 of 23



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. 10.8.2.3

For lots that were rejected for excessive or inadequate metal distortion angle (see Annex A.3.5), or squeeze roll pressures outside of the expected range: 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-bar13) and the associated standard deviations (S13) for each. If either of the following calculations is false reject the lot, finally: a)

X13 −µ2 x 606.3 /S13 ≤ 179.2

b)

12 × S132 σ ≤ 68.19

c)

Any production lot rejected while manufacturing to 6.1.5.2(c) may be retested in the following manner: 1)

Test 13 additional pipe lengths from the lot rejected and perform all testing required by 10.3 and 10.6.

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 A.3): 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-bar13), and X-bar for the ID normalizing width, and the associated standard deviations (S13) for each. If either of the following calculations is false reject the lot, finally:

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11


i)

X13 −µ2 x 606.3 /S13 ≤ 179.2

ii)

12 × S132 σ ≤ 68.19

Marking of the Pipes Pipe shall be marked as specified in the Purchase Order and/or the Manufacturer's Specifications

12

13

Coating and Protection 12.1

External Coating: Pipe shall be supplied with external mill coating unless specified otherwise in the Purchase Order. Varnish coating is acceptable provided that the varnish is hard drying with a maximum dry film thickness of 0.050 mm.

12.2

Internal Coating: Pipe shall be supplied with an internal anti-friction coating as per the Manufacturer's Specifications and Purchase Order Requirements.

Packaging for Shipment and Storage 13.1

Full length joints shall be shipped and stored in a bundled type packaging system that meets the following requirements:

13.2

Wedge or saddle type support/spacer segments.

13.3

Support/spacer segments to be polyethylene encapsulated steel i-beams.

13.4

Bundles shall be connected using side bolts.

13.5

Each bundle shall have four support/spacer segments lengthwise, one each near the ends and two more evenly spaced down the length of the pipe.

13.6

Six (6) inch and smaller pipes shall be packaged in bundles of 16 joints.

13.7

Seven (7) inch and larger pipes shall be packaged in bundles of 9 joints.

12 December 2006

Revision Summary New Saudi Aramco Materials System Specification.

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Annex A – Manufacturing Procedure Qualification A.

Introductory Note All pipes must be manufactured using a qualified Manufacturing Procedure and Quality Plan that has been approved by Saudi Aramco Drilling Engineering Department with assistance from Consulting Services Department/Materials Engineering & Corrosion Control Division (ME&CCD). Procedure submittals include A.1, A.2, and A.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. Physical, fax or email submittals are acceptable, but submittals by electronic spreadsheet program are preferred. Final acceptance of pipe is contingent upon successful qualification of a procedure and approval by Saudi Aramco Drilling Engineering Department with the assistance of Consulting Services Department, Materials Engineering & Corrosion Control Division, plus evidence that the pipe was manufactured within the limits of the Manufacturing Procedure (Post production report). 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 A.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 A.3) change, but the essential manufacturing variables are unchanged, then only the welding conditions (Annex A.3) must be requalified. Essential Manufacturing Variables:

A.1

a)

Pipe Grade

b

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 re-roller, if applicable, and the strip mill and shall state the thickness, and split width or slab or strip if applicable, of the slab from which 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 addendum. Completely describe the strip edge milling, CEPC and non-CEPC methods, Page 15 of 23



automatic seam tracking, and weld seam heat treatment, or full body normalizing, process and equipment. A.2

Manufacturing Procedure Qualification Tests Manufacturing procedure qualification test results to be submitted include:

A.3

a)

All tests required in Section 10. A complete series of tests shall be performed on at least one pipe from each coil described in A.3.3(c). If multiple welding lines will be used for production the same requirements shall apply to each pipe manufacturing line.

b)

Impact test results.

c)

Welding qualification as specified in Annex A.3.

d)

For the purpose of the first-time qualification only (Paragraph 6.1.3) the submittal may be based upon Annex A, A.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 addendum. If a purchase order is awarded on this basis, the specific qualifications required by Annex A.2 and A.3 shall be submitted and approved prior to start of production.

e)

SPC Procedure if CEPC method is not employed for control of any process variables. See Paragraph 6.1.5.2(b).

f)

SPC Procedure if CEPC method is used for control of only welding and heat treating heat input process variables. See Paragraph 6.1.5.2(c).

g)

Description of CEPC, if employed. See paragraph 6.1.5.2(a).

h)

Post production Process Control Report, for first time qualification, (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 A.3).

i)

Post production Process Control Report (see 6.1.3) after the completion of any current order. This report should be submitted separately from the qualification test report.

Qualification of Welding Conditions 1)

Essential welding variables: a.

Pipe grade Page 16 of 23


2)

3)


b.

Nominal diameter

c.

Specified wall thickness ± 1.0 mm

d.

Operation within qualified process limits (Figure 2)

e.

Contact tip/roller alloy composition (HFERW only)

f.

Induction coil configuration (HFI only)

g.

Impeder configuration (HFI only).

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).

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 #2 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 using the Excel spreadsheet program (see Figure 2).

c.

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 2. i)

Sample each coil at the front (top), middle, and end (bottom).

ii)

Evaluate each sample for compliance with 10.3 (flattening test) and 10.6 (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 10.6.3.4.

Page 17 of 23



Figure 2 4)

Figure 2, in terms of 6.1.5.2(c) represents the limits within which CEPC must control the processes.

5)

Perform the following calculations with the measurements made in 10.6.3.4 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-barQOD.

b)

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

c)

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

d)

Determine the standard deviation for all ID angles combined. This calculated value is defined as SQID. 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 SQOD or SQID, respectively, re-qualification shall be required after significant process improvement.

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6)

7.


The final process capability curve (Figure 2) 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, the CEPC system shall control process variables within the area bounded in Figure 2 in accordance with [see 6.1.5.2(a)]

b)

For pipe manufactured without any CEPC [see 6.1.5.2(b)] adequate SPC sampling must be accomplished in accordance with Annex C to assure the maintenance of the Qualified Process Limits in Figure 2 with a 95% confidence level.

c)

For pipe manufactured to 6.1.5.2(c) the distortion metal angle, and ID normalization zone, tests taken in accordance with 10.6.3.4 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 A.3.3 above. Any coil that does not pass all of the tests shall be rejected.

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Annex B – Non-Destructive Testing (NDT) B.1

General NDT Requirements and Acceptance Criteria 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.

B.2

NDT of HFW Pipe B.2.1 Non-destructive testing of the weld seam. B.2.2 Pipe shall be inspected to API 5CT SR2.

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Annex C – 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 A.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 addendum unless required by [6.1.5.2(c)], (6.2) or (10.6.3.4). a.

The sampling plan required for metallurgical control is to be used after steady state production conditions have been achieved or verified. Steady Page 21 of 23



state conditions are defined as changes in process variable settings that are still within the qualified process limits in Annex A.3, Figure 2. 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 Drilling Engineering Department for decision as to disposition with assistance from Consulting Services Department, Materials Engineering & Corrosion Control Division.

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 3).

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 10.6.3.4 of this document, and reject the lot if one specimen or sub-group fails.

7.

Rejected lots shall be re-inspected (10.8.2) 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 3 and the table above). Pipe production, under tightened inspection, which 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.

9.

Any product, by normal inspection, that results in the acceptance of 10 consecutive lots shall allow switching to reduced inspection (see Figure 3 and the table below). Page 22 of 23



Figure 3 – Statistical Process Control Cycle

Page 23 of 23

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