Document: NRC Regulatory Guide
Document ID: 44b58049-ac63-457b-a075-ef162b34cb70
Document Type: regulatory_guide
Title: Materials code case Acceptability - - ASME Section III, Division 1 (Rev. 31)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0037/ML003740365.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.85
CFR Part: 
CFR Title: 

Content:
of the sus ceptibility of high-strength materials to brittleness and stress corrosion cracking. Certain applications may ex ist where a UTS value of up to 190 Ksi could be consid ered acceptable for a material and, under this condition, the Design Specification should specify impact testing for the material. For these cases, it should be demon strated by the applicant that (1) the impact test results for the material meet code requirements and (2) the ma terial is not subject to stress corrosion cracking by vir tue of the fact that (a) a corrosive environment is not present and (b) the component that contains the mate rial has essentially no residual stresses or assembly stresses, and it does not experience frequent sustained loads in service. In the last sentence of paragraph 5.3, reference should be made to paragraph 4.5.2.2, "Alter nate Atmosphere Exposure Time Periods Established by Test," of the AWS D. 1.1 Code for the evidence pres ented to and accepted by the Authorized Inspector con cerning exposure of electrodes for longer periods of time. Paragraph 16.2.2 is not acceptable as written and should be replaced with the following: When not ex empted by 16.2.1 above, the postweld heat treatment shall be performed in accordance with NF-4622 except that for ASTM A-710 Grade A material, it shall be at least 1000'F (540'C) and shall not exceed 1150'F (6200C) for Class 1 and Class 2 material and 1175°F (6400C) for Class 3 material. The new holding time at temperature for weld thickness (nominal) shall be 30 minutes for 1/2 inch or less, 1 hour per inch for thick ness over 1/2 inch to 5 inches, and 5 hours plus 15 min utes for each additional inch over 5 inches. The fracture toughness requirements as listed in this Code Case ap- ply only to piping supports and not to Class 1, 2, and 3 component supports. The fracture toughness of Classes 1, 2, and 3 component supports shall be characterized in accordance with paragraph 5.3.4 of the USNRC Stan dard Review Plan