If hydrotesting induces cold deformation, is this acceptable as per NACE MR0175?
Is Overstressing Superaustenitic Stainless Steel and Ni-Based Alloy Valve Bodies during Hydrotesting Permissible under NACE MR0175/ISO 15156 Rules?
Introduction
This page features a question about whether the practice of slightly overstressing superaustenitic stainless steel and Ni-based alloy valve bodies during hydrotesting, which results in a cold deformation of 0.2-0.5%, is permissible under the rules of NACE MR0175/ISO 15156.
Answer
According to the relevant industry or design code, hydrotesting the austenitic stainless steels is acceptable. Specifically, this question pertains to NACE MR0175/ISO 15156-3 A.3 and A.4, and the reference cited is ISO 15156 Maintenance Panel Inquiry #2003-28 Q2.
Conclusion
In conclusion, while the practice of slightly overstressing superaustenitic stainless steel and Ni-based alloy valve bodies during hydrotesting may result in cold deformation, it is permissible under the rules of NACE MR0175/ISO 15156 as long as it is done in accordance with the relevant industry or design code.