ASME B31.1 BACKING BAR MATERIAL

[PMCap]

I AM FULL PENETRATION WELDING 1/2" THK P1 MATERIAL TO P5A MATERIAL AND USING A BACKING BAR. CODE IS ASME B31.1. BOTH BASE MATERIALS HAVE CARBON < 0.15% TO AVOID POST WELD HEAT TREATMENT. BACKING BAR WILL P1 MATERIAL

QUESTION: IS IT A CODE REQUIREMENT THAT THE P1 BACKING BAR MATERIAL ALSO HAVE CARBON < 0.15%

 

[r6155]

Backing strip is a poor option for butt welding, try to avoid it.
ASME B31.1 (2018) 127.2.2 is clear.
Regards

 

[goutam_freelance]

Even though backing ring is not desirable, if you want to use it then base metal and backing ring metal shall be compatible as per Cl. 127.2.2. So C content should be less than 0.15 %. Also regarding PWHT please check Table 132.2-1 for Mandatory requirements and exemptions. The backing ring should be removed after welding as indicated in ASME B31.1.

Engineers, think what we have done to the environment !

https://www.linkedin.com/in/goutam-das-59743b30/