Hardness of Carbon Steel Welds

[arcpro]

The hardness limit of carbon steel welds is usually kept at less than 200 HB.
At our locations, the hardness is coming out in the range of 210-220 HB. What are the main reasons and actions to be taken?
Can we go with these readings?

[ben]

Are you talking about pressure vessel welds or piping?
What is the design code?

[arcpro]

Piping. ASME B31.3

[mechcolor]

As per ASME B31.3, carbon steel weld joints are not mandatory to be checked for hardness after doing PWHT.
Is PWHT a service requirement in your case and project specifications ask for hardness check?

[arcpro]

Yes the actual material is A-333 Gr. 6 requiring PWHT as per specifications.

[mechcolor]

arcpro,
Officially, by the book, you just have to follow the requirements laid down by the project specifications / piping owner.
Off-the-record, hardness of killed carbon steel can be acceptable to 210 HB.
Talk to your piping owner / client. He has to give the final decision on this.
Most likely you would be repeating PWHT on weld joints exceeding the value mentioned in specs.

[arcpro]

Thanks Boss.