25 CR DUPLEX STAINLESS STEEL SEAMLESS PIPE, ASTM A790, BASED ON NORSOK M-630 MDS D51 REV 6, NORSOK M-650/ISO 17782 QUALIFICATION; QUALITY REQUIREMENTS INCLUDED

Summary

This specification covers the requirements for 25 Cr Duplex stainless steel seamless pipes based on NORSOK M-630 MDS D51 Rev. 6. Seamless pipes supplied to this specification shall comply with ASTM A790.

25 Cr Duplex materials are limited to a maximum of 3 psia (20 kPa) partial pressure H₂S in produced fluids and a maximum temperature of 450 °F (232°C).

Any modifications/additions to NORSOK/ASTM are highlighted in green color.

Restriction on UNS number: Only UNS S32750 and UNS S32760 shall be used.

Table of Contents

1.0 Scope

This specification covers the requirements for 25 Cr Duplex stainless steel seamless pipes. Manufacturing of parts to this specification shall be made in full compliance to ASTM A790, and all supplementary requirements provided by NORSOK M-630 MDS D51 rev. 6 except where modified by this specification.

Each supplier of pipes to this specification shall be qualified in accordance with NORSOK M-650/ISO 17782. The qualification shall be relevant for the exact product supplied, in accordance with the essential variables and limitations set within NORSOK M-650/ISO 17782. The supplier shall make the entire Qualification Test Record/ Manufacturer Procedure Conformity Records (QTR/MPCR), including supporting documentation required by the qualification standard, available for review by TechnipFMC upon request.

2.0 Reference Specifications

3.0 Manufacturing Process

Manufacturers and the manufacturing process used for manufacturing of products to this MDS shall be qualified in accordance with NORSOK M-650 or ISO 17782. The qualification testing shall meet the requirements of NORSOK M-630 MDS D51 rev. 6.

3.1 Chemical Requirements

The steel melt shall be refined with AOD or equivalent. The chemical analysis shall be in accordance with Table 2.

3.2 Heat treatment

The pipes shall be solution annealed followed by water quenching in accordance with ASTM A790. Furnaces shall be in compliance with NORSOK M-650/ISO 17782. Pipes shall be placed in such a way as to ensure free circulation of heating and cooling media around each pipe during the heat treatment process included accelerated cooling.

4.0 Metallurgical Properties

4.1 Extent of Testing and Test Sampling

One set of impact, tensile, hardness, corrosion testing and microstructure examinations shall be carried out for each heat and heat treatment lot (Lot is defined in ASTM A790).

Test specimens sampling is outlined in Table 3.

4.2 Tensile and Hardness Properties

Tensile testing shall be performed in accordance with ASTM A370 or ISO 6892-1. The material shall meet the tensile and maximum hardness properties of Table 4.

4.3 Impact Testing

Charpy V-notch testing shall be performed in accordance with ASTM A370, ASTM A1058 or ISO 148-1 (striker radius of 8 mm). Testing and results shall meet the requirements of Table 5.

4.4 Micrographic Examination

4.4.1 Preparation and Examination of Samples

Metallographic preparation and examination of 25 Cr Duplex stainless steels shall be in accordance with ISO 17781. The etchant to detect intermetallic phases and the ferrite balance electrolytic etching shall be performed after final polishing using the following solution:

• 20 % to 40 % NaOH or KOH solution or other suitable etchant(s), to show ferrite balance and intermetallic phases, listed in ISO 17781 Appendix B.

4.4.2 Intermetallic Phases

The microstructure shall basically be free from intermetallic phases. However, discrete/standalone intermetallic phases can be tolerated provided these are located in isolated areas and not homogeneously distributed throughout the test specimen, and that the maximum dimension of each phase does not exceed 10 μm.

The presence and location of intermetallic phases shall be noted and recorded with micrographs (400x minimum) representative of the location with the highest concentration of intermetallic phases.

If intermetallic phases are not detected, a representative micrograph (400x minimum) at or near mid-wall thickness shall be recorded. Micrographs shall be reported at the actual magnification and shall include a scale bar.

In case centerline intermetallic stringers are present, this shall be reported and acceptance of the product shall be based upon CVN and corrosion test results.

In the event the CVN testing cannot be completed due to geometry or size, intermetallic phases and/or precipitates are not permitted.

4.4.3 Ferrite content

The ferrite content per ASTM E 562 or by image analysis according to ASTM E 1245 shall be performed in accordance with ISO 17781.

The acceptance criteria shall be:

• 35 % to 60 %.

4.5 Corrosion Test

Corrosion testing per ASTM G48 Method 'A' (50˚C, 24h) shall be performed in accordance with ISO 17781.

The acceptance criteria shall be:

• No pitting at 20X magnification.
• The weight loss shall be less than 1.0 g/m².

5.0 Non-Destructive Evaluation (NDE)

5.1 Personnel

Personnel performing NDE shall be qualified and certified to level II or III in accordance with ISO 9712 or equivalent. The roles and responsibilities of NDE personnel shall be as defined in ISO 9712.

5.2 Ultrasonic testing

The pipe base material shall pass a 100 % ultrasonic testing for longitudinal defects in accordance with ASTM E213 or ISO 10893-10. Ultrasonic testing shall be performed after all mechanical processing, heat treatments and straightening operation. Longitudinal (axial) reference notches shall be introduced on the outer and inner surfaces of the calibration (reference) standard in accordance with Figure 3 of ASTM E213 to a depth not greater than the larger of 0.3 mm or 5 % of specimen thickness (U2/C) and a length not more than 50 mm.

Acceptance criteria:

• Any indication greater than that produced by the calibration notch represent a defect; defective pipe and tubing shall be rejected or repaired.

6.0 Dimensional Requirements

Dimensional tolerances shall be per applicable ASTM standard, unless otherwise stated in TechnipFMC's part report or drawing.

7.0 Surface conditions

Finished pipes shall be white pickled or bright annealed.

8.0 Marking

The pipes shall be marked to ensure full traceability to melt and heat treatment lot.

9.0 Repairs of Defects

Weld repairs are not acceptable.

10.0 Documentation and Certification

The material manufacturer shall have an appropriate quality-assurance system, such as ISO 9001, certified by a competent body established within the EEA and having undergone a specific assessment for materials.

10.1 Documents to be Submitted

The following document in addition to other requirements on the part report or drawing shall be submitted to TechnipFMC for approval:

• Supplier NORSOK M-650/ISO 17782 Manufacturing Summary identification or QTR/MCPR that demonstrates qualification for the size and product form on the part report (SIR131).

10.2 Documents to be Submitted With Product Delivery

The following document in addition to other requirements on the part report or drawing shall be transmitted to TechnipFMC and traceable to the products being delivered (SIR205).

The material certificate shall be issued in accordance with EN 10204, Type 3.1, and shall include the following information required by ASTM A790 and NORSOK M-630:

• NORSOK M-650/ISO 17782 Manufacturing Summary identification or QTR/MPCR number used.
• Steel producer of the starting material.
• Steel melting practice and refining method.
• Heat number.
• Chemical analysis results: ladle analysis.
• Solution annealing temperature, holding time and quench medium shall be stated.
• Results of all metallurgical testing required by this specification.
• Results of all non-destructive testing required by this specification.