minimum amount of time before NDE 3

[Downhand]

Do any of the North American codes state the minimum amount of time that a weld should sit for before NDE is performed? I believe it is either 24 or 48 hours. Please reference the applicable code.

 

[Ron]

As a practical matter, as soon as it cools to ambient temperature.

 

[GRoberts]

From AWS D1.1: Acceptance criteria for ASTM A 514, A
517, and A 709 Grade 100 and 100W steels shall be
based on NDT performed not less than 48 hours after
completion of the welds.

 

[metengr]

...and the reason for delayed NDT for these higher strength steels is because of delayed cracking from hydrogen absorbed during the welding process.

 

[Downhand]

That's exactly what I was looking for GRoberts.

Thank you

 

[Ron]

Downhand...that's only for specific high strength steels. If you are working with mild steel, it would not apply.

 

[HgTX]

D1.5 has waiting periods for fracture-critical bridge steel as well.

Hg

Eng-Tips policies: faq731-376