Weld repairs - ASME Section VIII

[jrupert24]

Does this code define major and minor weld repairs? Where can I find it or can someone give me a head start? I know its a fairly generic quesiton, but it is mostly related to PWHT after a repair is made.

 

[metengr]

jrupert24;
"Major" and "minor" weld repairs are subjective terms, and the Code (ASME B&PV Code) does not address subjective terms.

The guidelines for PWHT in the Code are rather descriptive for repairs that exceed a certain percentage of the wall thickness because the excavation would be filled to restore the wall thickness back to original. Here is where the subjective terms of major versus minor originated, where "major" mandates the use of PWHT, while "minor" would require only a local preheat with no PWHT.

 

[jrupert24]

Thanks, the reason I am asking this question is because we have a spec that says that a crack in a P8 material is considered when it is 1-1/2" deep (along with several other materials and dimensions). The spec refers to Section VIII UHA-32. I can't find that statement anywhere for P8 materials let alone any of the others. THe only one I can find that says 1-1/2 is for certain grades of carbon steels.

Can you point me to a specific example, say P8?

 

[metengr]

P8 (austenitic stainless steel) base materials do not require post weld heat treatment because they cannot be hardened by thermal treatment (see Table UHA-32 in ASME Section VIII, Div 1). The P8 base materials can be re-solution annealed to obtain optimum corrosion resistance in service.

 

[deanc]

metengr is correct.

Many times a Major or Minor is addressed in the QC System.

Such as: A Major would be repairs to the base metal and a Minor is repairs to a weld.

But if you are behind and the completion date was yesterday, its all Major.

 

[VeryPicky]

ASME BPV Code addresses only the new fabricated vessels, not repairs. Neither does it deal with various services. For the repairs i suggest API 510 for inspection and National Board Inspection Code old ANSI NB-23 for suggested repairs. Also, do your self a favour: do not stick the austenitic stainless steel into the PWHT furnace, unless it is absolutely necessary and ensure it is annealing rather than just stress relief.

Owner/User should specify in their standards and specifications, what is considered minoror major repair and what actions (repairs, inspection, testing) need to be taken in both cases.

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