AS1210 - Australian standard

[Chiller]

Does anyone know why all AS1210 class 1 vessels need to be stress relieved?

Can the vessel still be class 1 if it wasn't PWHT?

Considering the vessel is CS and the internals are SS (all welded) is this a wise thing to do?

If there are no answers to the above, is there a forum / website / contact who can give me some assistance?


Many thanks in advance.

 

[GordonF]

Hi

I cannot answer your question directly as I am not sure which clause in 1210 calls for PWHT of all class 1 pressure vessels?


Cheers

 

[Chiller]

AS1210 table 1.6 states under manufacture :-

"PWHT - Generally required except for some materials"

Ordinary CS isn't in the "some materails" category.

 

[GordonF]

My understanding is, , that the PWHT requirements are specified in AS4458 (see table 14.1), as per AS1210 table 1.6. For example for CS materials (group A1) PWHT is generally not required for thickness below 32 mm.

In your case, I agree that it would not be a wise to PWHT as the PWHT temperatures will probably be in the sensitising range for SS. AS4458 also states that PWHT can be ommitted in special circumstances (clause 14.3) and you may have to call on that clause to get around PWHT if required by Table 14.1.

Either way, you will still need to qualify your weld procedures as per AS3992.

Cheers