gp 29-01-02-aug03

GP 29-01-02 Upstream Duplex Stainless Steel Requirements August 2003

Upstream Duplex Stainless Steel Requirements

GP 29-01-02

Scope This Global Practice (GP) covers the minimum requirements for procuring, fabricating, testing, and inspecting Duplex 22%Cr and Super Duplex 25%Cr Stainless Steels.

Upstream For ExxonMobil Use Only Version 1.0.0

of 71 ©ExxonMobil Development Company


Table of Contents

1. Required References ............................................................................................ 4

1.1. ASME–American Society of Mechanical Engineers ..................................... 4 1.2. ASTM–American Society for Testing and Materials ..................................... 4

2. Use of this Global Practice................................................................................... 5

2.1. General......................................................................................................... 5 2.2. Material Technical Sheets ............................................................................ 5 2.3. Welding Duplex 22% Cr and Super Duplex 25% Cr SS Technical Sheet..... 5 2.4. Fischer Ferrite Scope Specification .............................................................. 5

3. Duplex 22% Cr Stainless Steel / Technical Sheets............................................. 7

3.1. Technical Sheet: Duplex 22% Cr Stainless Steel Bars and Shapes............ 7 3.2. Technical Sheet: Duplex 22% Cr Stainless Steel Castings ....................... 10 3.3. Technical Sheet: Duplex 22% Cr Stainless Steel Forgings ....................... 13 3.4. Technical Sheet: Duplex 22% Cr Stainless Steel Plate ............................. 16 3.5. Technical Sheet: Duplex 22% Cr Stainless Steel Process Tubing ............ 18 3.6. Technical Sheet: Duplex 22% Cr Stainless Steel Seamless Pipe ............. 21 3.7. Technical Sheet: Duplex 22% Cr Stainless Steel Wrought Fittings ........... 24 3.8. Technical Sheet: Duplex 22% Cr Stainless Steel Welded Pipe................. 27

4. Duplex 25% Cr Stainless Steel / Technical Sheets........................................... 30

4.1. Technical Sheet: Super Duplex 25% Cr Stainless Steel Bars and Shapes30 4.2. Technical Sheet: Super Duplex 25% Cr Stainless Steel Castings............. 33 4.3. Technical Sheet: Super Duplex 25% Cr Stainless Steel Forgings............. 36 4.4. Technical Sheet: Super Duplex 25% Cr Stainless Steel Plate .................. 39 4.5. Technical Sheet: Super Duplex 25% Cr Stainless Steel Process Tubing.. 42 4.6. Technical Sheet: Super Duplex 25% Cr Stainless Steel Seamless Pipe... 45 4.7. Technical Sheet: Super Duplex 25% Cr Stainless Steel Wrought Fittings. 48 4.8. Technical Sheet: Super Duplex 25% Cr Stainless Steel Welded Pipe ...... 51 4.9. Technical Sheet: Super Duplex 25% Cr Stainless Steel Umbilical Tubing 54

5. Welding Duplex 22% Cr and Super Duplex 25% Cr Stainless Steels / Technical Sheet................................................................................................... 57

6. Fischer Ferrite Scope Specification .................................................................. 63

6.1. Introduction................................................................................................. 63

UPST For ExxonMobil Use Only Version 1.0.0



6.2. Scope ......................................................................................................... 63 6.3. Equipment .................................................................................................. 63 6.4. Calibration Standards and Blocks............................................................... 63 6.5. Applicability ................................................................................................ 64 6.6. Surface preparation .................................................................................... 64 6.7. Calibration of Equipment ............................................................................ 65 6.8. Ferrite Measurements ................................................................................ 66 6.9. Ferrite Measurement Locations .................................................................. 67 6.10. Evaluations of Results ................................................................................ 68 6.11. Personnel Qualifications............................................................................. 69

Record of Change ....................................................................................................... 70

Attachment: Purpose Codes Definitions.................................................................. 71




1. Required References This Section lists Practices and Standards that are generically referenced and assumed to be a part of this document. Unless otherwise specified herein, use the latest edition.

1.1. ASME–American Society of Mechanical Engineers

ASME B16.34 Valves - Flanged, Threaded, and Welding End

ASME SEC V BPVC Section V - Nondestructive Examination

ASME SEC VIII D1 BPVC Section VIII - Rules for Construction of Pressure Vessels - Division 1

1.2. ASTM–American Society for Testing and Materials

ASTM A 182/A 182M Standard Specification for Forged or Rolled Alloy-Steel Pipe Flanges, Forged Fittings, and Valves and Parts for High-Temperature Service

ASTM A 240/A 240M Standard Specification for Chromium and Chromium-Nickel Stainless Steel Plate, Sheet, and Strip for Pressure Vessels and for General Applications

ASTM A 262 Standard Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels

ASTM A 276 Standard Specification for Stainless Steel Bars and Shapes

ASTM A 370 Standard Test Methods and Definitions for Mechanical Testing of Steel Products

ASTM A 380 Standard Practice for Cleaning, Descaling, and Passivation of Stainless Steel Parts, Equipment, and Systems

ASTM A 450/A 450M/A 450M

Standard Specification for General Requirements for Carbon, Ferritic Alloy, and Austenitic Alloy Steel Tubes

ASTM A 789/A 789M Standard Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Tubing for General Service

ASTM A 790/A 790M Standard Specification for Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe

ASTM A 815/A 815M Standard Specification for Wrought Ferritic, Ferritic/Austenitic, and Martensitic Stainless Steel Piping Fittings

ASTM A 890/A 890M Standard Specification for Castings, Iron-Chromium-Nickel-Molybdenum Corrosion-Resistant, Duplex (Austenitic/Ferritic) for General Application

ASTM A 928/A 928M Standard Specification for Ferritic/Austenitic (Duplex) Stainless Steel Pipe Electric Fusion Welded with Addition of Filler Metal




ASTM A 995/A 995M Standard Specification for Castings, Austenitic-Ferritic (Duplex)

Stainless Steel, for Pressure-Containing Parts

ASTM E 407 Standard Practice for Microetching Metals and Alloys

ASTM E 562 Standard Test Method for Determining Volume Fraction by Systematic Manual Point Count

ASTM G 48 Standard Test Methods for Pitting and Crevice Corrosion Resistance of Stainless Steels and Related Alloys by Use of Ferric Chloride Solution

2. Use of this Global Practice

2.1. General 1) This Global Practice was designed to allow the individual Technical Sheets and Sections to be

extracted from this document and submitted with standard material specifications for procurement and fabrication.

2) The Technical Sheets identify additional material testing requirements deemed necessary by Company in order for the material to meet its intended service life.

2.2. Material Technical Sheets 1) The individual Technical Sheets shall be used as supplemental requirements to existing material

specifications (e.g., ASTM, ISO, UNS, etc.).

2) The Technical Sheets reflect the additional requirements of Company imposed on the manufacturers and material suppliers in order to maintain a quality level that is consistent for the material being supplied.

3) The Technical Sheets shall not be used as stand-alone documents for procuring or fabricating materials or components.

2.3. Welding Duplex 22% Cr and Super Duplex 25% Cr SS Technical Sheet

1) The Welding Technical Sheet shall be used as supplemental requirements to existing welding qualification codes, standards, and specifications.

2) The Welding Technical Sheet shall become an integral part of the Technical Sheets when submitted to manufacturers or suppliers for material or components that require fabrication by welding.

3) The Welding Technical Sheet shall not be used as a stand-alone document for welding qualifications.

2.4. Fischer Ferrite Scope Specification 1) This Section of the GP is intended to be used for nondestructive measurements of ferrite content in

Duplex Stainless Steels using a Fischer ferrite scope model MP30.




2) This Section shall be used and become an integral part of the Technical Sheets whenever the

Technical Sheets indicate a Nondestructive Ferrite Measurement is required.

3) This Section shall also be used when any Duplex or Super Duplex materials are fabricated by welding.

4) This Section shall be used in conjunction with Company specifications for the individual duplex products.




3. Duplex 22% Cr Stainless Steel / Technical Sheets

3.1. Technical Sheet: Duplex 22% Cr Stainless Steel Bars and Shapes

Technical Sheet 3.1: Duplex 22% Cr Stainless Steel Bars and Shapes

Product Form Bars and Shapes (including, but not limited to, rounds, hexagonals, angles, tees, etc.)

Material 22% Chromium Ferritic/Austenitic Stainless Steel, often referred to as Duplex Stainless Steel.

Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for duplex stainless steel bar products and rolled shapes. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand-alone document.

Manufacturer Approval

Materials supplied in accordance to this specification shall only be supplied by Company approved manufacturers.

Specification ASTM A 276

Grade(s) UNS S31803

Manufacturing Process

Electric arc or electric furnace and refined by AOD or equivalent process.

Heat Treatment All material shall be delivered in the solution annealed followed by water quench condition.

Pitting Resistance Equivalent

Pitting Resistance Equivalent (PRE) = Cr + 3.3Mo + 16N. The PRE shall be greater than or equal to 34.0

Hardness Per ASTM standard. If no hardness required by ASTM standard, maximum shall be HRC 28, HB 271, or HV 290





-- Charpy V-notch (ASTM A 370)

-- Not applicable when the maximum obtainable Charpy specimen has a width along the notch of less than 2.5 mm.

-- Absorbed energy shall be 48J average and 36J single value minimum.

-- Test temperature shall be minus 46°C.

-- Specimens shall be oriented transverse to the rolling direction.

Impact Testing

-- When product shape or dimensions prevent the use of transverse specimens, then longitudinal specimens may be used.

ASTM E 562

-- Ferrite content shall be determined by manual point count at locations near the surface of the shape and at mid-thickness

-- Samples shall be electrolytically etched in either NaOH or KOH, and in such a manner as to provide optimum contrast for austenite and ferrite phase discrimination

-- Point count shall be conducted at a minimum of 500X magnification

-- A minimum of 30 fields and 16 points per field shall be used

Ferrite Content

-- Ferrite content shall be between 35% - 55%

-- Metallographic examination shall be conducted on samples taken from near the surface of the shape and from mid-thickness.

-- Samples shall be etched using ASTM E 407 etchant number 98 (K3Fe(CN)4 with KOH or NaOH)

-- Etching shall be performed in such a manner as to provide optimum resolution of potential precipitates

-- Examination shall be conducted at a minimum of 500X magnification.

Metallographic Examination

-- Intermetallic phases or precipitates are allowed up to a max. of 0.05 percent.

Extent of Testing All testing shall be conducted on each heat, size, shape configuration, and heat treatment lot.

Repair of Defects Weld repairs are not allowed

Surface Finish White Pickled





-- Product shall be handled, shipped and stored in such a manner as to prevent or minimize the possibility of free iron contamination

-- Product shall not be handled with bare steel hooks, chains or lifting forks without the use of protective insulating material

-- Only stainless steel wire brushes, designated for use only on stainless steel products, may be used for brushing and descaling

-- Suspected free iron contamination, such as evidenced by unusual stains or discoloration, shall be verified by ferroxyl testing in accordance with the procedures outlined in ASTM A 380

Handling, Shipment, and Storage

-- Free iron contaminated areas shall be cleaned and passivated, at the manufacturer’s expense, using the procedures outlined in ASTM A 380

Certification EN 10204 - 3.1B




3.2. Technical Sheet: Duplex 22% Cr Stainless Steel Castings

Technical Sheet 3.2: Duplex 22% Cr Stainless Steel Castings

Product Form Castings (for valve bodies, pump housings, fittings, and misc. machinery components, etc.)


Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for duplex stainless steel castings. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand alone document.



Specification ASTM A 890/A 890M, ASTM A 995/A 995M

Grade(s) 4A (UNS J92205)

Supplemental requirements

S2, S3, S33



Heat Treatment All material shall be delivered in the solution annealed (followed by water quench) condition.



Hardness Per ASTM standard. If no hardness required by ASTM standard, maximum shall be HRC 28, HB 271, or HV 290.




Impact Testing






ASTM E 562

-- Ferrite content shall be determined by manual point count

-- Two specimens shall be taken, one from the center of the test piece and another from just below the surface of the test piece




Ferrite Content


-- Metallographic samples shall be taken from the same locations as the ferrite content coupons as described above.





-- Intermetallic phases or precipitates are allowed up to a max. of 0.05 percent.

-- Test samples shall be taken from the parent material, which is either a sacrificial casting, or from an integral cast extension off of an actual production part.

-- Test samples shall be representative of the heaviest section of the production casting.

Test Sampling

-- The test sample parent material shall accompany the actual production parts through all heat treat and quench cycles.

Extent of Testing All testing shall be conducted on each heat and heat treatment load.





-- Liquid Penetrant - All castings shall be liquid penetrant examined in accordance with S3 requirements on all accessible surfaces. Acceptance criteria shall be in accordance with ASME SEC VIII D1, Appendix 7.

-- Radiographic – Supplementary requirement S2 shall apply to:

-- Critical areas per ASME B16.34 of the pilot cast of each pattern

-- Class 600 and 900; all butt weld ends

-- Class 1500 psi and above; all critical areas to ASME B16.34

Inspection

-- Acceptance criteria for radiographic inspection shall be in accordance with ASME SEC VIII D1, Appendix 7.

-- All castings shall have ferrite content determined, in a minimum of three locations including both the heaviest section and the thinnest section, by Fischer ferrite scope.

-- Measurements shall be taken at least 3 mm (0.125 in) below the surface of the casting.

-- Measurement technique shall be in accordance with Company approved procedures.

Non-destructive Ferrite Measurement


Repair of Defects Weld repairs shall be qualified on an actual cast plate of the same composition and qualification testing shall include all requirements for the original casting as described above. Castings shall be heat treated after any major repairs in accordance with S33 requirements. Minor defects may be repaired without PWHT using properly qualified weld repair procedures.












3.3. Technical Sheet: Duplex 22% Cr Stainless Steel Forgings

Technical Sheet 3.3: Duplex 22% Cr Stainless Steel Forgings

Product Form Forgings


Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for duplex stainless steel forgings. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand alone document.



Specification ASTM A 182/A 182M

Grade(s) F 51 (UNS S31803)


S2





Pitting Resistance Equivalent (PRE) = Cr + 3.3Mo + 16N. The PRE shall be greater than or equal to 34.0.




-- Absorbed energy shall be 48J average and 36J single value minimum

Impact Testing

-- Test temperature shall be minus 46°C





ASTM E 562






Ferrite Content

-- Ferrite content shall be between 35% – 55%





-- Intermetallic phases or precipitates are allowed up to a max. of 0.05 percent

-- Test samples shall be taken from an actual (sacrificial) test forging or from a prolongation off of the actual part.

-- The test sample shall be from a location which is representative of the heaviest section of the production forging.

Test Sampling

-- The test sample parent forging shall accompany the actual production forgings through all heat treat and quench cycles.


-- 20% of forgings shall be liquid penetrant examined. Inspection

-- Acceptance criteria shall be in accordance with ASME SEC VIII D1, Appendix 8.

-- All forgings shall have ferrite content determined, in a minimum of three locations including both the heaviest section and the thinnest section, by Fischer ferrite scope.




Repair of Defects Weld repairs are not allowed.





3.4. Technical Sheet: Duplex 22% Cr Stainless Steel Plate

Technical Sheet 3.4: Duplex 22% Cr Stainless Steel Plate

Product Form Plate

(for pressure-containing components such as vessel shells or for fabricated components such as plate type heat exchangers)


Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for duplex stainless steel plate. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand alone document.




Grade(s) UNS S31803

Supplemental Requirements

S1








-- Not applicable when maximum obtainable Charpy specimen has a width along the notch of less than 2.5 mm.

-- Absorbed energy shall be 48J average and 36J minimum single value.


Impact Testing





Technical Sheet 3.4: Duplex 22% Cr Stainless Steel Plate

ASTM E 562

-- Ferrite content shall be determined by manual point count at locations near the top and bottom plate surfaces and at mid-wall.

-- Samples shall be electrolytically etched in either NaOH or KOH, and in such a manner as to provide optimum contrast for austenite and ferrite phase discrimination.

-- Point count shall be conducted at a minimum of 500X magnification.


Ferrite Content


-- Metallographic examination shall be conducted and shall cover the entire plate cross section.





Extent of Testing All testing shall be conducted on each heat, size, and heat treatment lot.













3.5. Technical Sheet: Duplex 22% Cr Stainless Steel Process Tubing

Technical Sheet 3.5: Duplex 22% Cr Stainless Steel Process Tubing

Product Form Process Tubing


Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for duplex stainless steel process tubing. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand alone document.




Grade(s) UNS S31803


Electric arc or electric furnace and refined by AOD or equivalent process









Impact Testing






ASTM E 562

-- Ferrite content shall be determined on a full cross section near the OD and ID surfaces and at mid-wall location.





Ferrite Content

-- Ferrite content of the seam weld shall be 25 % - 60 %.

-- Samples shall be etched using ASTM E 407 etchant number 98 (K3Fe(CN)4 with KOH or NaOH).

-- Sample cross section shall be examined at OD, ID and mid-wall locations.




Extent of Testing All testing shall be conducted on a lot basis. A lot is defined as the same tubing diameter, thickness, heat and heat treatment charge, up to a maximum of 125 tubes.

-- 10% of all tubes shall have ferrite content determined by Fischer ferrite scope.




Hydrostatic Test In accordance with ASTM A 789/A 789M and ASTM A 450/A 450M

Repair of Defects Weld repair of defects is not allowed





3.6. Technical Sheet: Duplex 22% Cr Stainless Steel Seamless Pipe

Technical Sheet 3.6: Duplex 22% Cr Stainless Steel Seamless Pipe

Product Form Seamless Pipe


Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for duplex stainless steel seamless pipe. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand-alone document.




Grade(s) UNS S31803








-- Not applicable when the maximum obtainable Charpy specimen has a width along the notch of less than 2.5 mm


Impact Testing






ASTM E 562

-- Ferrite content shall be determined on a cross section near the OD and ID surfaces and at mid-wall location.




Ferrite Content







Extent of Testing All testing shall be conducted on a lot basis. A lot is defined as a maximum of 60 meters of pipe of the same diameter, thickness, heat and heat treatment charge.

Hydrostatic Test In accordance with ASTM A 790/A 790M

-- 10% of all products shall have ferrite content determined by Fischer ferrite scope.









3.7. Technical Sheet: Duplex 22% Cr Stainless Steel Wrought Fittings

Technical Sheet 3.7: Duplex 22% Cr Stainless Steel Wrought Fittings

Product Form Wrought Fittings


Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for duplex stainless steel wrought fittings. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand-alone document.



Specification(s) ASTM A 815/A 815M

Class Class WP-S, WP-W, WP-WX

Grade UNS S31803


S2, S7













-- Test base metal and weld metal (if applicable)



-- Base metal specimens shall be oriented transverse to the pipe axis. When base metal dimensions prevent the use of transverse specimens, then longitudinal specimens may be used.

Impact Testing

-- Weld metal specimens shall be oriented across the weld.

ASTM E 562

-- Ferrite content shall be determined on a prepared cross section and shall include measurements near the OD and ID surfaces and at mid-wall for each location: base metal, heat affected zone and weld metal (if applicable).

-- Samples shall be electrolytically etched in either NaOH or KOH, and in such a manner as to provide optimum contrast for austenite and ferrite discrimination.



Ferrite Content



-- Sample cross section shall be examined at OD, ID and mid-wall for each location: base metal, heat affected zone and weld metal (if applicable).




Extent of Testing All testing shall be conducted on one actual (sacrificial) sample from each heat and heat treatment lot.

Inspection Liquid penetrant examination in accordance with S7 supplemental requirements shall apply to 20% of all fittings.





-- All fittings shall be checked for ferrite content, in both the base metal and the weld metal (if applicable) by Fischer ferrite scope.

-- Three base metal and three weld metal (if applicable) locations shall be measured.




Repair of Defects Weld repair of base material is not allowed. Repair of welds shall be subject to identical acceptance criteria as original weld.












3.8. Technical Sheet: Duplex 22% Cr Stainless Steel Welded Pipe

Technical Sheet 3.8: Duplex 22% Cr Stainless Steel Welded Pipe

Product Form Welded Pipe


Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for duplex stainless steel welded pipe. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand-alone document.




Class Class 1, 3 and 5

Grade UNS S31803









-- Test base metal and weld metal.




Impact Testing






ASTM E 562

-- Ferrite content shall be determined on a prepared cross section and shall include measurements near the OD and ID surfaces and at mid-wall for each location: base metal, heat affected zone and weld metal.





Ferrite Content

-- Ferrite content of the seam weld shall be between 25 % - 60 %.


-- Sample cross section shall be examined at OD, ID and mid-wall for each location: base metal, heat affected zone and weld metal.





-- Welds shall be radiographed to the extent required by the pipe class. Inspection

-- 10% of the welds shall be liquid penetrant examined in accordance with ASME SEC V, Article 6. Acceptance shall be in accordance with ASME SEC VIII D1, Appendix 7.

-- Ferrite content of longseam welds shall be determined on 10% of production pipe, in three locations, by Fischer ferrite scope.










4. Duplex 25% Cr Stainless Steel / Technical Sheets

4.1. Technical Sheet: Super Duplex 25% Cr Stainless Steel Bars and Shapes

Technical Sheet 4.1: Super Duplex 25% Cr Stainless Steel Bars and Shapes

Product Form Bars and Shapes (including but not limited to rounds, hexagonals, angles, tees, etc.)

Material 25% Chromium Ferritic/Austenitic Stainless Steel, often referred to as Super Duplex Stainless Steel.

Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for super duplex stainless steel bar products and rolled shapes. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand-alone document.



Specification ASTM A 276

Grade(s) UNS S32750, UNS S32760, UNS S32550













-- Absorbed energy shall be 48J average and 36J single value minimum



Impact Testing

-- When product shape or dimensions prevent the use of transverse specimens, then longitudinal specimens may be used.

ASTM G 48 method A

-- Test temperature shall be 50°C

-- Exposure time shall be 24 hours

-- Specimens shall be tested in the as-received condition (samples shall not be pickled or passivated prior to test).

-- Specimen sides (only) may be ground to 600 grit and the edges may be rounded.

Corrosion Testing

-- Acceptance criteria: No pitting at 20X and maximum weight loss shall be 4.0 g/m2

ASTM E 562

-- Ferrite content shall be determined by manual point count at locations near the surface of the shape and at mid-thickness




Ferrite Content


-- Metallographic examination shall be conducted on samples taken from near the surface of the shape and from mid-thickness.










Extent of Testing All testing shall be conducted on each heat, size, shape configuration, and heat treatment lot.













4.2. Technical Sheet: Super Duplex 25% Cr Stainless Steel Castings

Technical Sheet 4.2: Super Duplex 25% Cr Stainless Steel Castings

Product Form Castings (for valve bodies, pump housings, fittings, and misc. machinery components, etc.)


Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for super duplex stainless steel castings. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand-alone document.



Specification ASTM A 890/A 890M, ASTM A 995/A 995M

Grade(s) 5A (UNS J93404), 6A (UNS J93380)


S2, S3, S33










Impact Testing

-- Test temperature shall be minus 46°C





ASTM G 48 method A





Corrosion Testing


ASTM E 562






Ferrite Content








-- Test samples shall be taken from the parent material which is either a sacrificial casting or from an integral cast extension off of an actual production part.

-- Test samples shall be representative of the heaviest section of the production casting.

Test Sampling

-- The test sample parent material shall accompany the actual production parts through all heat treat and quench cycles.





Extent of Testing All testing shall be conducted on each heat and heat treatment load. The test sample shall accompany the actual production parts through all heat treat and quench cycles.

-- Liquid Penetrant - All castings shall be liquid penetrant examined in accordance with S3 requirements on all accessible surfaces. Acceptance criteria shall be in accordance with ASME SEC VIII D1, Appendix 7.

-- Radiographic – Supplementary requirement S2 shall apply to:

-- Critical areas per ASME B16.34 of the pilot cast of each pattern

-- Class 600 and 900; all butt weld ends

-- Class 1500 psi and above; all critical areas to ASME B16.34

Inspection

-- Acceptance criteria for radiographic inspection shall be in accordance with ASME SEC VIII D1, Appendix 7.

-- All castings shall have ferrite content determined by Fischer ferrite scope.

-- Measurements shall be taken at least 3 mm (0.125 in) below the surface of the casting.




Repair of Defects Weld repairs shall be qualified on an actual cast plate of the same composition and qualification testing shall include all requirements for the original casting as described above. Castings shall be heat treated after major repairs in accordance with S33 requirements. Minor defects may be repaired without PWHT using properly qualified weld repair procedures.












4.3. Technical Sheet: Super Duplex 25% Cr Stainless Steel Forgings

Technical Sheet 4.3: Super Duplex 25% Cr Stainless Steel Forgings

Product Form Forgings


Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for super duplex stainless steel forgings. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand-alone document.




Grade(s) F 53 (UNS S32750), F 55 (UNS S32760), F61 (UNS S32550)


S2










Impact Testing






ASTM G 48 method A





Corrosion Testing


ASTM E 562






Ferrite Content







-- Test samples shall be taken from an actual (sacrificial) test forging or from a prolongation off of the actual part.

-- Test samples shall be representative of the heaviest section of the production forging.

Test Sampling

-- The test sample parent forging shall accompany the actual production forgings through all heat treat and quench cycles.






-- 20% of forgings shall be liquid penetrant examined. Inspection

-- Acceptance criteria shall be in accordance with ASME SEC VIII D1, Appendix 8.

-- All forgings shall have ferrite content determined by Fischer ferrite scope.




Repair of Defects Weld repairs are not allowed.












4.4. Technical Sheet: Super Duplex 25% Cr Stainless Steel Plate

Technical Sheet 4.4: Super Duplex 25% Cr Stainless Steel Plate

Product Form Plate (for pressure containing components such as vessel shells or for fabricated components such as plate type heat exchangers)

Material 25% Chromium Ferritic/Austenitic Stainless Steel often referred to as Super Duplex Stainless Steel.

Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for super duplex stainless steel plate. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand-alone document.






S1









-- Absorbed energy shall be 48J average and 36J minimum single value.


Impact Testing






ASTM G 48 method A





Corrosion Testing


ASTM E 562

-- Ferrite content shall be determined by manual point count at locations near the top and bottom plate surfaces and at mid-wall.




Ferrite Content


-- Metallographic examination shall be conducted and shall cover the entire plate cross section.

-- Samples shall be etched using ASTM E 407 etchant number 98 (K3Fe(CN)4

-- with KOH or NaOH)




Extent of Testing All testing shall be conducted on each heat, size, and heat treatment lot.






4.5. Technical Sheet: Super Duplex 25% Cr Stainless Steel Process Tubing

Technical Sheet 4.5: Super Duplex 25% Cr Stainless Steel Process Tubing

Product Form Process Tubing


Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for super duplex stainless steel process tubing. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand-alone document.





Manufacturing

Process









Impact Testing






ASTM G 48 method A





Corrosion Testing


ASTM E 562

-- Ferrite content shall be determined on a full cross section near the OD and ID surfaces and at mid-wall location.




Ferrite Content







Extent of Testing All testing shall be conducted on a lot basis. A lot is defined as the same tubing diameter, thickness, heat and heat treatment charge, up to a maximum of 125 tubes.











4.6. Technical Sheet: Super Duplex 25% Cr Stainless Steel Seamless Pipe

Technical Sheet 4.6: Super Duplex 25% Cr Stainless Steel Seamless Pipe

Product Form Seamless Pipe


Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for super duplex stainless steel seamless pipe. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand-alone document.














Impact Testing






ASTM G 48 method A





Corrosion Testing


ASTM E 562

-- Ferrite content shall be determined on a cross section near the OD and ID surfaces and at mid-wall location.




Ferrite Content


Samples shall be etched using ASTM E 407 etchant number 98 (K3Fe(CN)4 with KOH or NaOH)

Sample cross section shall be examined at OD, ID and mid-wall locations.

Examination shall be conducted at a minimum of 500X magnification.


Intermetallic phases or precipitates are allowed up to a max. of 0.05 percent












4.7. Technical Sheet: Super Duplex 25% Cr Stainless Steel Wrought Fittings

Technical Sheet 4.7: Super Duplex 25% Cr Stainless Steel Wrought Fittings

Product Form Wrought Fittings


Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for super duplex stainless steel wrought fittings. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand-alone document.




Class Class WP-S, WP-W, WP-WX

Grade UNS S32750, UNS S32760, UNS S32550


S2, S7













-- Test base metal and weld metal (if applicable).




Impact Testing


ASTM G 48 method A



-- One base metal and one weld metal (if applicable) sample (with weld oriented transverse and centered in the sample) shall be tested.



Corrosion Testing


ASTM E 562

-- Ferrite content shall be determined on a prepared cross section and shall include measurements near the OD and ID surfaces and at mid-wall for each location: base metal, heat affected zone and weld metal (if applicable).




Ferrite Content







-- Sample cross section shall be examined at OD, ID and mid-wall for each location: base metal, heat affected zone and weld metal (if applicable).




Extent of Testing All testing shall be conducted on one actual (sacrificial) sample from each heat and heat treatment lot.

Inspection Liquid penetrant examination in accordance with S7 supplemental requirements shall apply to 20% of all fittings.

-- All fittings shall be checked for ferrite content, in both the base metal and the weld metal (if applicable) by Fischer ferrite scope.
















4.8. Technical Sheet: Super Duplex 25% Cr Stainless Steel Welded Pipe

Technical Sheet 4.8: Super Duplex 25% Cr Stainless Steel Welded Pipe

Product Form Welded Pipe


Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for super duplex stainless steel welded pipe. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand-alone document.




Class Class 1 and 3

Grade UNS S32750, UNS S32760, UNS S32550


S4












-- Not applicable when maximum obtainable Charpy specimen has a width along the notch of less than 2.5 m..

-- Test base metal and weld metal.




Impact Testing


ASTM G 48 method A



-- One base metal and one weld metal sample (with weld oriented transverse and centered in the sample) shall be tested.



Corrosion Testing


ASTM E 562





Ferrite Content












-- Welds shall be radiographed in accordance with ASTM A 928/A 928M. Inspection

-- 10% of the welds shall be liquid penetrant examined in accordance with ASME SEC V, Article 6. Acceptance shall be in accordance with ASME SEC VIII D1, Appendix 7.

-- Ferrite content of longseam welds shall be determined on 10% pipe, in three locations, by Fischer ferrite scope.

















4.9. Technical Sheet: Super Duplex 25% Cr Stainless Steel Umbilical Tubing

Technical Sheet 4.9: Super Duplex 25% Cr Stainless Steel Umbilical Tubing

Product Form Umbilical Tubing


Scope This material Technical sheet is intended to supplement existing material standards and specifications (e.g., ASTM, ISO, UNS, etc.,) and project specifications for super duplex stainless steel umbilical tubing. The requirements specified on this Technical sheet are in addition to the requirements established by the governing standard. In case of conflict between this standard and the governing standard, the more stringent requirement(s) shall apply. This Technical sheet is not intended to serve as a stand-alone document.





Manufacture Electric arc or electric furnace and refined by AOD or equivalent process

Material Composition

C: 0.025, Mn: 1.00, P: 0025, S: 0.008, Si: 0.75, Ni: 6.0–8.0, Cr: 24.0-26.0, Mo: 3.0–4.5, N: 0.24–0.31, Cu: 1.0, W: 1.0, B: 30 ppm, O: 100 ppm, Sn: 200 ppm, As: 200 ppm, Sb: 50 ppm (single values are maximum allowable)

Heat Treatment All material shall be delivered in the solution annealed (followed by a suitable quenching method) condition.




-- Charpy V-notch (ASTM A 370) - Applicable for tubing greater than 3mm thick.


Impact Testing


Flattening Test ASTM A 450/A 450M

No cracks allowed during first step ductility test (use e = 0.08)





ASTM A 450/A 450M

-- Flare to 10% (measured on the inside diameter of the tube) using a 60° conical mandrel

Flaring Test

-- No cracks allowed

ASTM G 48 method A



-- Specimen shall be full thickness and in the as-received condition (samples shall not be pickled or passivated prior to test).


-- All surfaces shall be exposed to the test solution


Corrosion Testing

ASTM A 262 method E (Strauss test)

ASTM E 562


-- Ferrite content shall be determined at OD, ID and at mid-wall




Ferrite Content











Extent of Testing All testing, with exception of the Strauss test (ASTM A 262 method E), shall be conducted on a lot basis. A lot is defined as the same tubing diameter, thickness, heat and heat treatment charge, up to a maximum of 125 tubes. Strauss test shall be conducted once per order.


All tubes shall be 100% ultrasonic examined in accordance with ASTM E 213 or 100% eddy current examined in accordance with ASTM E 426.

-- Eddy current calibration standard bore shall be:

-- 0.8 mm for tubes OD ≤ 32 mm

-- 1.20 mm for tubes: 32 mm < OD ≤ 40 mm



-- 2.00 mm for tubes: OD > 65 mm

Inspection

-- Ultrasonic calibration standard notch shall have a depth ≤ 10% of tube wall thickness, and width ≤ 0.5 mm, and maximum notch length 25 mm.

-- 100% of umbilical tubes shall have ferrite content determined, in a minimum of three locations, by Fischer ferrite scope.





Surface Finish Bright Annealed











5. Welding Duplex 22% Cr and Super Duplex 25% Cr Stainless Steels / Technical Sheet

Welding Duplex 22% Cr and Super Duplex 25% Cr Stainless Steels

Application Duplex and Super Duplex Stainless Steel Welding

Scope This material Technical sheet is intended to supplement existing welding and fabrication codes, standards and specifications (e.g., ASME SEC IX, EN 288 etc.) for the welding of duplex and super duplex stainless steel. The requirements specified on this Technical sheet shall be in addition to the requirements established by the governing welding codes and standards. In case of conflict between this standard and the governing code or standard, the more stringent requirement(s) shall apply. This specification applies to Mill, Field and Shop welding of duplex and super duplex stainless steel. This Technical sheet is not intended to serve as a stand-alone document.

-- GTAW, SMAW, SAW, PAW

-- For Umbilical Tubing: Automatic welding shall be used except where limited by accessibility.

Acceptable Welding Processes

-- For all other components: Automatic, semiautomatic or manual welding is allowed

-- For SMAW: Only basic and semi-basic coatings are allowed. The core wire shall contain the nominal as-deposited alloy composition.

Electrodes

-- For SAW: Active fluxes are prohibited





For all welding applications:

-- Electrode manufacturer and specific brand name

-- UNS Number

For Umbilical Tubing:

-- Electrode manufacturer and specific brand name

-- UNS Number

-- Electrode batch and lot

-- Change in wall thickness ± 25% of that qualified.

-- Change in nominal tubing diameter (D) from the following groupings:

-- D ≤ 1 in. (25 mm)

-- 1 in. (25 mm)> D < 2 in.(50 mm)

-- 2 in. (50 mm) ≥ D ≤ 4 in. (100 mm)

Additional Essential Variables (to supplement ASME SEC IX or EN 288 requirements)

-- D > 4 in. (100 mm)

Autogenous Welding

Autogenous welding shall be allowed, however, all autogenous welds shall have a minimum of two passes, except for Process or Umbilical Tubing (only) with wall thickness < 2 mm, which may be autogenous welded with a single pass.

-- Backing gas shall be used and flow shall be maintained until the weld is completed.

-- Backing gas shall be 100% Argon or an Argon / 5% Nitrogen mixture (5% Nitrogen maximum).

Backing Gas

-- Oxygen shall be < 500 ppm.

In addition to the governing code requirements for welder qualification, each welder shall demonstrate the ability to deposit welds with the appropriate ferrite content as part of the qualification process. Ferrite measurement of the qualification weld shall be as follows:

-- Measurement shall be made by Fischer ferrite scope at four evenly spaced positions (3, 6, 9, and 12 o’clock positions) around the circumference of a qualification test weld pipe.

-- Measurements shall be made in accordance with Company approved ferrite scope procedures

-- Ferrite content shall be 30% – 60%

Welder Qualification (supplementary requirements)

-- For previously qualified welders, the first production weld may be used for ferrite content qualification.





Filler metal Pitting Resistance Equivalent, defined as:

(PRE) = Cr +3.3Mo + 16N.

The filler metal PRE shall be as follows:

-- For welding UNS S31803 (22% chromium duplex), the PRE shall be equal to or greater than 34.0

-- For welding UNS S32750 or UNS S32760 (25% chromium “super” duplex), the PRE shall be equal to or greater than 40.0

Filler Metal Pitting Resistance Equivalent

-- For welding Umbilical Tubing, the PRE shall be equal to or greater than 41.0

Charpy V Notch impact testing shall be performed for each welding procedure qualification in accordance with the following:

-- Charpy V-notch per ASTM A 370, (3 test specimens per set)

-- Not applicable when the maximum obtainable Charpy specimen has a width along the notch of less than 2.5 mm

-- Charpy samples shall be taken across the weld.

-- Notch placement shall be in the weld center, FL, FL +2mm and FL +5mm (total of 4 sets per qualification)


Impact Testing

-- Test temperature shall be minus 46°C, regardless of the LAST.

Each welding procedure qualification test shall be hardness tested. Hardness shall be measured on a prepared weld cross section. Hardness shall be measured in the base metal, HAZ and weld metal. Maximum hardness shall be:

-- For UNS S32750, UNS S32760, UNS S32550: HRC 32, HB 302, or HV 319

Hardness

-- For UNS S31803: HRC 28, HB 271, or HV 290





Corrosion testing shall be performed for each welding procedure qualification in accordance with the following:

-- ASTM G 48 Method A.

-- Exposure time shall be 24 hours.

-- Specimens shall be full thickness.

-- Sample shall include the weld oriented in the transverse direction in the center of the sample and the sample shall include both heat affected zones and associated unaffected base metal.

-- All surfaces shall be exposed. The sides (only) may be ground to a 600 grit finish and the edges may be rounded.

-- Samples shall not be pickled or passivated prior to test.

-- Test temperature for UNS S31803 weld samples (22% chromium duplex) shall be 20°C.

-- Test temperature for UNS S32750, UNS S32760 weld samples (25% chromium “super” duplex) and for Umbilical Tubing, shall be 40°C.

-- Acceptance criteria:

For Umbilical Tubing: No pitting at 20X and maximum weight loss shall be less than 1.5 g/m2.

Corrosion Testing

For all Other Components: No pitting at 20X and maximum weight loss shall be less than 4.0 g/m2

Ferrite measurements shall be performed on each welding procedure qualification in accordance with the following:

ASTM E 562





Ferrite Measurement

-- Ferrite content shall be between 30% – 60%





Each welding procedure qualification shall have a metallographic examination in accordance with the following:






Production welds shall have ferrite measurements in accordance with the following:

-- A Fischer ferrite scope shall be used.

-- Measurement technique shall be in accordance with Section 5, Fischer Ferrite Scope Specification, of this specification.

-- Ferrite content shall be 30% – 60%.

-- For all subsea pipeline stainless steel components (including umbilicals) = 100%

-- For all 25 % Cr Duplex SS = 100 %

Production Welds - Ferrite Measurement

-- For all 22 % Cr Duplex SS = 10 %

For Umbilical Tubing:

-- 100% dye penetrant inspection of production welds.

-- 100% radiographic inspection in accordance with ASME B31.3 requirements.

For all other applications:

-- 10% dye penetrant inspection of production welds.

Inspection

-- Radiographic inspection in accordance with project specifications or purchase order requirements.

Surface Finish Welds shall be free of slag and weld spatter





-- Welded product shall be handled, shipped and stored in such a manner as to prevent or minimize the possibility of free iron contamination

-- Welded product shall not be handled with bare steel hooks, chains or lifting forks without the use of protective insulating material

-- Only stainless steel wire brushes, designated for use only on stainless steel products, shall be used for brushing, cleaning and descaling




-- Only two repairs shall be allowed per weld. After two repair cycles, the weld shall be cut-out and rewelded.

-- WPS shall be qualified for the number and type of weld repairs to be made.

Weld Repairs

-- The WPS shall meet all the testing requirements of the design code and this technical sheet.




6. Fischer Ferrite Scope Specification

6.1. Introduction Duplex stainless steels have a ferritic/austenitic microstructure and the performance of the material depends on the balance between the ferrite and the austenite content. To be able to perform a check on the ferrite content during manufacture, fabrication and as a spot check (verification check), magnetic test methods have been developed. There are several commercially available instruments that are designed to measure the ferrite content in duplex stainless steels. One such instrument is the Fischer ferrite scope (Feritscope®), for which this specification was developed and which is described in Section 6.3 of this document.

6.2. Scope 1) This specification shall be used for non-destructive measurements of ferrite content in duplex

stainless steels using a ferrite scope.

2) This specification describes how ferrite measurements shall be carried out and at which locations.

3) This specification is intended to cover all duplex stainless steel products including welding.

4) This specification shall be used in combination with ExxonMobil product specifications for the individual duplex products as these specifications give more detailed information related to the ferrite content acceptance criteria as well as extent of inspection (measurements).

6.3. Equipment

1) This specification was developed for ferrite measurements using a Fischer ferrite scope (feritscope) model MP30.

2) Other Fischer ferrite scope models may be used provided they are calibrated according to Section 5.4 below.

3) The use of other Fischer ferrite scope, or the use of non-Fischer instruments, shall require written approval from Company.

4) The use of the term “ferrite scope” in this GP refers specifically to the Fischer Feritscope MP30.

6.4. Calibration Standards and Blocks 1) The calibration of the ferrite scope shall be traceable to internationally approved IIW secondary

calibration standards.

2) A copy of the calibration certificate from Fischer shall be available together with the equipment (valid for new equipment).

3) The equipment shall have calibration blocks that are traceable to the IIW secondary calibration standards.

4) A copy of the calibration certificate for the calibration blocks shall be available together with the blocks.




5) The equipment shall have calibration blocks that cover the ferrite range 25 to 70 %.

6.5. Applicability

6.5.1. Material thickness 1) The ferrite measurements may be influenced by the material thickness (typically when the thickness

is below 2.5 mm [0.1 in.]).

2) The measured ferrite content for thin materials shall be corrected for thickness in accordance with guidelines given in the operating manual of the equipment.

6.5.2. Specimen Curvature / Diameter 1) Ferrite content can be measured directly on flat surfaces and curved surfaces above a minimum

specified radius of curvature.

2) This minimum radius is specified in the operating manual for the equipment and corrections to the measured ferrite content for smaller radii shall be done in accordance with guidelines given in the operating manual.

6.6. Surface preparation

6.6.1. General 1) Whenever grinding is necessary to obtain a proper measurement surface, the finishing grinding shall

be with a minimum 400 grit wheel, belt-sander (or equivalent).

2) Ferrite measurements shall not be employed directly on angle ground surfaces.

3) In case of an angle ground surface, a minimum of 0.125 mm (0.005 in.) further grinding shall be performed with grinding wheels up to 400 grit to free the measurement surface of any pre-existing angle grinding marks.

6.6.2. Rolled, Wrought, and Forged products Measurements shall be carried out on a clean surface ground in accordance with Section 6.6.1 above.

6.6.3. Welds 1) The cap of welds shall be ground flat to the extent that ferrite readings can be obtained with the probe

in use.

2) The grinding finish shall be in accordance with Section 6.6.1 above.

6.6.4. Castings 1) Ferrite measurements on cast products shall in general be performed at subsurface location, at a depth

greater than 3 mm (0.125 in.) below the cast surface. When grinding is performed, note comments about grinding finish as given in Section 6.6.1 above.

2) When grinding is performed, care must be taken to ensure that minimum wall thickness requirements are not violated.




3) The ferrite measurement must not be performed within a discontinuity or near to an edge as this will

give inaccurate readings.

4) As a guideline, the distance to a discontinuity or an edge shall be more than two times the probe diameter.

6.7. Calibration of Equipment 1) Fischer ferrite scopes have several levels of calibration as described in detail in the operating manual

of the equipment.

2) The calibration procedures as described in the operating manual shall be followed.

3) The following gives a brief description of different levels of calibration. Further, additional requirements are described.

6.7.1. Normalization (re-zero) for Thin and Curved Materials 1) As mentioned in Section 6.5 above, ferrite measurements shall be corrected when thin or curved

materials are inspected.

2) This correction can be done using correction curves given in the operating manual of the equipment.

3) The correction can also be done by “normalizing” the equipment to a thin or curved material. In such a case, a 100 % ferritic material with the same thickness or curvature as the one to be inspected is used to calibrate/normalize the equipment. After this normalization, the equipment will automatically correct for thin material/curved surface.

6.7.2. Corrective Calibration 1) A corrective calibration of the equipment shall be performed whenever the probe is changed.

2) As the probe wears, the calibration frequency should be increased.

3) Excessively worn probes, as indicated by unstable measurements, as defined in Section 6.8.4 of this document, shall not be used.

4) Corrective calibration shall further be performed, whenever the check of the calibration status gives unacceptable results (see Section 6.8.2 below).

6.7.3. Master Calibration 1) A master calibration of the equipment has been performed by the manufacturer using internationally

accepted, secondary standards (TWI secondary standard set).

2) The master calibration of the equipment shall in general not be altered.

3) A new master calibration may be necessary if the original calibration has been lost due to memory failure. In such a case, records shall show when the equipment was re-calibrated.

4) In case of a master calibration, the procedures as outlined in the operating manual of the equipment shall be adhered to.

5) In case corrective calibration of the equipment at different ferrite levels can not give correct ferrite levels, a master calibration of the equipment may be carried out using the master calibration standard set as provided with the instrument.




6) Prior to a master calibration, the manufacturer of the equipment should be consulted and the

equipment checked for malfunction (e.g., significantly worn probes).

7) In case of a successful master calibration, this shall be recorded.

8) In case of a non-successful master calibration, the equipment shall not be used.

6.8. Ferrite Measurements

6.8.1. General 1) In addition to requirements given in this specification, ferrite measurements shall be performed in

accordance with ExxonMobil product specifications for duplex stainless steels.

2) ExxonMobil specifications give inspection frequency and acceptance criteria to ferrite range.

3) A ferrite measurement consists of a minimum of three individual readings from the same spot.

4) Results of the ferrite measurements shall be documented and reported as % ferrite and to the nearest whole number.

6.8.2. Check of Calibration Status 1) Prior to a series of measurements, the calibration status of the equipment shall be checked.

2) The calibration shall be checked using the corrective calibration standard set as supplied with the equipment and selecting calibration blocks with a ferrite content close to the expected upper and lower measuring range.

3) If the measurement gives readings significantly different from the actual ferrite level of the reference objects, the instrument shall be re-calibrated.

4) Maximum allowable difference of ferrite content shall be ± 5 % of nominal value.

6.8.3. Surface preparation Surfaces shall be prepared for measurements as described in Section 6.6 above at locations described below.

6.8.4. Ferrite content measurements 1) When performing ferrite measurements on a product, repeated individual measurements shall be

performed on the same spot until stable readings are obtained.

2) A minimum of three readings shall be obtained from the same spot.

3) A valid measurement is obtained when the readings are stable, which is defined as three sequential readings within 2% ferrite on a flat surface, and three sequential readings within 3% ferrite on a curved surface.

4) If valid readings can not be obtained, the measurement surface shall be ground further and the measurements repeated.

5) Worn probes, as well as measurement technique, can influence measurements and should be addressed whenever unstable measurements occur.




6.9. Ferrite Measurement Locations

6.9.1. Plates 1) Ferrite measurements shall be performed at the rolled surface close to one corner of the plate.

2) Distance from the plate sides at the corner shall be minimum two times the diameter of the probe.

6.9.2. Tubes and Pipes 1) Ferrite measurements shall be performed for the base material at the outer surface of each tube/pipe

end.

2) In case of seam welded tubes/pipes, ferrite measurements shall also be performed for the weld.

3) For the weld cap, ferrite measurements shall be performed at each end as well as at mid length of the tube/pipe.

4) Where access permits, ferrite measurements shall be performed for the weld root at each end of the pipe.

5) When performing measurements at the tube/pipe ends, the distance from the tube/pipe end shall not be less than 50 mm (2 in.).

6.9.3. Umbilical Tubes/Pipes, Welded Joints

1) For tubes/pipes with outer diameter (OD) ≤ 25 mm (1 in.) ferrite measurements shall be performed for the weld metal at two locations, the welding start/stop location and at a location 180° away from the start/stop locations.

2) For tubes/pipes with outer diameter (OD) > 25 mm (1 in.) ferrite measurements shall be performed for the weld metal at four locations, the welding start/stop location and further around the weld circumference with a spacing of 90°.

6.9.4. Fittings 1) Ferrite measurements shall be as a minimum performed at both the thinnest and the thickest part of

the fitting.

2) In case of welded fittings, the welds shall be measured.

6.9.5. Induction Bends 1) Ferrite measurements shall be performed across the start transition and stop transition of the induction

bent area on the extrados side.

2) Five measurements in a row covering the transition from unaffected base material to fully induction-heated material shall be performed.

3) A minimum of four additional measurements, covering the inner arc, outer arc, tangent start and tangent stop areas, shall be performed.

4) If the induction bend contains a longitudinal weld seam, ferrite measurements shall be performed in the weld metal, cap, and root (whenever access permits this) in the same positions as specified above for the base material.




6.9.6. Forgings 1) Ferrite measurements shall be, as a minimum, performed at two locations, one at the thinnest and one

at the thickest part of the forging.

2) For forgings of equal thickness, a minimum of two locations shall be examined for ferrite content.

6.9.7. Bars and shapes 1) For bars, ferrite measurement shall be carried out at one location.

2) For shapes of varying wall thickness, ferrite measurements shall be, as a minimum, performed at two locations, one at the thinnest and one at the thickest part.

3) In case of even wall thickness, ferrite measurements shall be carried out at one location.

6.9.8. Castings 1) Ferrite measurements shall as a minimum be performed at two locations, one at the thinnest and one

at the thickest part of the casting.

2) For castings of equal thickness, a minimum of two locations shall be examined for ferrite content.

6.9.9. Welds (Welded Joints) 1) The weld cap shall either be ground flush prior to ferrite measurements or part of the weld cap shall

be ground to a flat surface in order to obtain reproducible results.

2) When performing the measurements, the probe shall be positioned in the center of the weld.

6.9.9.1. Welds on Plate, Structures and Pressure Vessels

1) In connection with fabrication welds, one ferrite measurement per 1.8 m (6 ft) of weld shall be performed for each welding process.

2) Minimum four measurements shall be performed for each fabricated component.

3) For smaller components where the requirement to four measurements applies, the measurement locations shall be picked at random, but shall as much as possible cover different welding positions/methods/wall thickness.

6.9.9.2. Girth Welds in Piping

1) For tubes/pipes with outer diameter (OD) ≤ 25 mm (1 in.) ferrite measurements shall be performed for the weld metal at two locations, the welding start/stop location and at a location 180° away from the start/stop locations.

2) For tubes/pipes with outer diameter (OD) > 25 mm (1 in.) ferrite measurements shall be performed for the weld metal at four locations, the welding start/stop location and further around the weld circumference with a spacing of 90°.

6.10. Evaluations of Results 1) In case the valid measurement at one measuring location gives readings outside the specified ferrite

content range, two additional locations shall be measured in the vicinity of the first measuring point.




2) If either of the additional locations yields ferrite readings outside the specified ferrite content, the

product shall be rejected.

3) If the two additional measuring points give readings within the ferrite content acceptance range, additional surface preparation shall be performed for the first measuring location and the measurement repeated. If acceptable result is obtained, the product shall be accepted.

4) The above assumes that the calibration status of the equipment has been checked and found in good order.

6.11. Personnel Qualifications 1) Personnel (operators) performing ferrite measurements shall be familiar with the equipment and the

operating manual of the same. This GP and its content shall also be familiar to the operator.

2) Operators under training shall be supervised by an experienced operator that has used the equipment on a regular basis for at least 6 months. Training shall be documented.

3) Whenever requested, the operator shall be able to demonstrate a check of the equipment calibration status and to perform a measurement series followed by an evaluation of the test results.




Record of Change

Version 1.0.0 Date: 08/03

Location Action Description

Initial Publish.

Version 1.0.0 Date: 11/03

Global Practice version number and format updated to comply with new process; however, original publish date remains, and no content was modified.




Attachment: Purpose Codes Definitions

Code Description

C Assigned to paragraphs containing specifications whose primary purpose is reduced costs. Reduced cost in this context refers to initial investment cost and does not include Life-Cycle cost considerations. Life-Cycle cost considerations are captured under reliability, maintainability, or operability purpose codes.

E Assigned to paragraphs containing specifications whose primary purpose is driven by environmental considerations. Environmental considerations typically include specifications intended to protect against emissions/leakage to the air, water, and/or soil. Deviations from the specifications contained in such paragraphs require formal review and approval according to local environmental policy.

I Assigned to paragraphs that provide only clarifying information such as Scope statements, definitions of terms, etc.

M Assigned to paragraphs containing specifications whose primary purpose is to provide for maintainability of equipment or systems. Maintainability provisions are those that facilitate the performance of maintenance on equipment/systems either during downtimes or during on-stream operations.

O Assigned to paragraphs containing specifications whose primary purpose is to assure operability of equipment or systems. Operability is the ability of the equipment/system to perform satisfactorily even though conditions are off-design, such as during startups, process swings, subcomponent malfunction, etc.

R Assigned to paragraphs containing specifications whose primary purpose is to improve or assure the reliability of equipment or systems. Reliability is a measure of the ability of equipment/systems to operate without malfunction or failure between planned maintenance interventions.

S Assigned to paragraphs containing specifications whose primary purpose is avoidance of personnel or operational safety incidents. Any deviation from the specifications contained in such designated paragraphs requires formal review and approval according to local safety policy.

Personnel Safety: Refers to the avoidance of recordable personnel injuries; i.e., burns, cuts, abrasions, inhalation, or exposure to dangerous substances, etc., that could result in medical treatment, restricted work, lost-time incidents, or fatalities.

Operational Safety:

Refers to the prevention and control of process releases, fires, explosions, etc.



gp 29-01-02-aug03

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