Special requirements for duplex stainless steel

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Specifications for duplex stainless steel materials – Special requirements 1, Materials 1.1, UNS S31803/S32205 Requirements 1.1.1, All materials shall be subjected to solution annealing and water quenching. 1.1.2 The nitrogen content of all materials should be above 0.14%. 1.1.3 Seamless steel pipes are made from conventional billets. 1.2, UNS S32550 requires 1.2.1: All materials with a thickness of less than 9.5 millimeters (0.375 inches) shall be solution-annealed and then quickly cooled in air or quenched in water. All materials with a thickness of 9.5 millimeters (0.375 inches) or more shall be solution-annealed and quenched in water. 1.2.2 The nitrogen content of all materials should be above 0.18%. 1.2.3 Seamless steel pipes are made from conventional billets. Seamless steel pipes are manufactured using conventional billet or powder metallurgy methods. 1.3, UNS S32750 requires 1.3.1: All materials shall be solution-annealed and quenched in water. 1.3.2 Seamless steel pipes are made from conventional billets. 1.4 The thin steel plates shall be bright-annealed or pickled, with a surface finish of 2D. 1.5 The steel plates should be pickled. 1.6 Steel plates/steel sheets with a thickness of 19 millimeters (0.75 inches) or less shall be cut to the required final width and length using shearing, wet grinding saws, or plasma arc cutting (PAC). If using PAC, the highest cutting speed should be employed to minimize heat input as much as possible. The cutting angle should not exceed 3 degrees, and the roundness of the top edge at any point along the cut should not exceed 0.8 millimeters (1/32 inch) in radius. The slag on the cut area/adjacent steel plate should be removed to ensure a smooth and uniform final cut surface. 1.7 Processed products obtained through hot forming or cold forming that achieve an external fiber elongation of more than 10% (i.e., end caps, pipe fittings, etc.) shall undergo solution annealing at the temperature specified in the standards, followed immediately by water quenching. Products that have undergone annealing and quenching shall be tested in accordance with 2.1.1, and the test results shall meet the requirements of 3.1.1.1 and 3.1.1.2. 1.7.1 If heat treatment is required during the prefabrication of the head, the temperature should be maintained for at least 30 minutes. The temperature should be recorded using a thermocouple installed on the head. 1.7.2 For products that have been solution-annealed and water-quenched in accordance with the requirements of 1.1.6, the required tests can be carried out using specimens. The specimens should be taken from the materials used in the product, as well as from the materials that are processed and annealed/quenched using the product. 1.7.3 Under any circumstances, the manufacturing process employed by the supplier of the processing unit must include annealing, quenching, and testing in accordance with the requirements of 1.1.6; the supplier shall arrange for the owner’s inspectors to be present on site to oversee the supplier’s processing, solution annealing, and quenching processes. 1.8 The interior and exterior of the processed head should be inspected using coloring methods. Refer to the acceptance criteria in ASME Chapter VIII, Section 1, Appendix 8. 1.9 The processing unit must purchase materials from qualified suppliers. 2. Test 2.1: According to ASTM A-923 Method C, a corrosion test was conducted to verify the absence of harmful intermetallic phases. Method A of ASTMA-923 should not be used as a basis for accepting materials. 2.1.1 Unless otherwise specified by the owner, corrosion tests shall be conducted on the following: 2.1.1.1 Steel plates or thin steel plate coils for each furnace batch. 2.1.1.2 Each batch of steel pipes as defined in ASTM A790, paragraph 8.1. 2.1.1.3 Each batch of steel pipes as defined in Note 2 of Paragraph 8.3 of ASTM A789. 2.1.1.4 Flanges, castings, and pipe fittings for each furnace batch in each heat treatment batch. 2.1.1.5 Heat treatment for each batch of other finished products in 1.7. 2.1.2 The test specimens of welded products shall contain the base metal, heat-affected zone, and weld metal. 2.1.3 For materials not listed in Table A-923-3, the test temperatures and acceptance criteria are as follows: Maximum allowable corrosion rate for material tests – S32550 (non-welded products): 30°C, 10MDD; S32550 (welded products): 27°C, 10MDD; S32750 (welded products): 37°C, 10MDD. 3. Documentation 3.1 All materials must be accompanied by a factory inspection report or certificate, confirming that they meet the requirements of these specifications. 3.1.1 All certificates shall report the corrosion rate determined according to 2.1, testing harmful intermetallic phases. The test results should be traceable to the purchased materials. 3.1.2 If required, the applicable certificate shall report the results of the Charpy impact test per ASTM A370. The test results should be traceable to the purchased materials. 4. Welding 4.1 All welding procedure specifications must be verified through corrosion testing; in accordance with ASTM A-923 Method C, they shall be free of harmful intermetallic phases. ASTM A-923 Method A should not be used as the basis for procedural acceptance. Each program eligibility record requires one test. The test temperature and acceptance criteria shall be the same as those specified in 2.1.3 or Table 3 of ASTM A-923. For the procedural qualification of joining different grades of duplex stainless steel, the test temperature shall be that of the grade with the lower test temperature.