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Weldment with Nickel greater than 1%, does NACE MR0175 / ISO 15156-2 subclause A.2.1.4 say they are not acceptable?

 

Question: ISO 15156-2 subclause A2.1.4 Welding has the following two paragraphs: “Carbon steel and low-alloy steel weldments that do not comply with other paragraphs of this subclause shall be stress-relieved at a minimum temperature of 620 °C (1150 °F) after welding. The maximum weld zone hardness, determined in accordance with 7.3, shall be 250 HV or, subject to the restrictions described in 7.3.3, 22 HRC”. “Welding consumables and procedures that produce a deposit containing more than 1 % mass fraction nickel are acceptable after successful weld SSC qualification by testing in accordance with Annex B”. Based on this, I interpret the requirements as follows: If there are weldments with Ni contents greater than 1% mass fraction, they can be accepted if the weld procedures are successfully tested to SSC qualification in accordance with Annex B. Alternately, weldments with Ni contents greater than 1% mass fraction shall be acceptable if stress-relieved at a minimum temperature of 620 °C (1150 °F) after welding. The maximum weld zone hardness, shall be 250HV or 22 HRC in that case.Please can you confirm the interpretation.

Answer:

The intent of the next to last paragraph in A.2.1.4 (15156-2, Annex A) dealing with the 620C (1150F) SR option does not negate the requirement in the following paragraph which requires SSC qualification testing regardless of SR if the weld deposit is >1% Ni.

This question is in relation to NACE MR0175/ISO 15156-2 Annex A.2.1.4

Reference: ISO 15156 Maintenance Panel Inquiry #2013-07

At Oil & Gas Corrosion we see many enquiries related to stress relief and nickel content in weldments. Weldments with Ni contents greater than 1% mass fraction shall be qualified.

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