Lower temperature limit for stud use in ASME

The point raised by the original poster is very crucial. SA-193 Gr.B7M is a commonly chosen material for low-temperature applications, but ASME specifies a minimum operating temperature. Generally, Table 1B in ASME BPVC Section II Part D (the table of allowable stresses for carbon steel and low-alloy steel) can be referred to; it lists the allowable stress values at various temperatures, with the lowest values occurring around -48°C. However, for the B7M grade specifically, it is necessary to check whether impact testing has been conducted; according to ASME BPVC Section VIII Div.1 UCS-66, if no impact testing is performed, the lower operating temperature limit is set at -29°C. It is recommended that the original poster check the table for SA-193 Gr.B7M in the latest version of ASME BPVC Section II Part D, or consult the appendix of the SA-193 standard, which provides detailed information on the temperature ranges. If the temperature is below -29°C, it is necessary to verify whether the material has passed the low-temperature impact test, and design codes (such as Section VIII, B31.3, etc.) also specify different conditions for exemptions from such impact tests. The final data must be based on the latest version of the standards; if you are unsure, you can consult a professional engineer or obtain an NDT inspection report for verification.

This post was last edited by xinchen on 2026-6-22 11:42. First of all, thank you very much for your reply! For the SA-193 Gr.B7M, the maximum applicable temperature can be found in Table 1B of Part D; is there no minimum applicable temperature? In SA-193, I couldn’t find out what the lower operating temperature limit is What is the lowest operating temperature for UG20f at -29°C, and for UCS66 without the need for impact testing at -48°C?

Search for “Teaching you how to understand ASME’s MDMT””

Isn’t Table 1B the allowable stress table for non-ferrous materials? Can I check on SA-193 Gr.B7M?

Or should we judge it based on UCS66?