thread725-386609
I was searching for some information on 8630 and this post came up (the linked one) and I do not think the whole story is told and understood. The DNV person in the background discussion was correct in a cold repair qualified on 4130 is only good for a clad repair on 4130, because the resulting hardness in the base metal after the repair is what we care about.
Cold repairs are done on clad surfaces to fix nicks, machining errors, wear or what not. The underling base metal is an alloy that requires PWHT. The idea is the part does not go through PWHT after the cold repair.
This is not a simple ASME IX qualification, it normally includes hardness requirements from NACE for cracking resistance. Therefore only using the variables ASME IX will lead to problems, this is where good welding engineering judgment is called for.
The common requirements are:
The base metal to be used (4130, F22 or some other alloy requiring PWHT when welded on)in production for repair
A clad layer is put on
The sample is PWHT
The depth of desired repair is machined into the clad layer
Weld up machined area
Do the bends, macros, hardness and chemistry
If the base metal is reheated enough the hardness will go up and probably fail the hardness requirements.
Thanks,
Peter
Peter
I was searching for some information on 8630 and this post came up (the linked one) and I do not think the whole story is told and understood. The DNV person in the background discussion was correct in a cold repair qualified on 4130 is only good for a clad repair on 4130, because the resulting hardness in the base metal after the repair is what we care about.
Cold repairs are done on clad surfaces to fix nicks, machining errors, wear or what not. The underling base metal is an alloy that requires PWHT. The idea is the part does not go through PWHT after the cold repair.
This is not a simple ASME IX qualification, it normally includes hardness requirements from NACE for cracking resistance. Therefore only using the variables ASME IX will lead to problems, this is where good welding engineering judgment is called for.
The common requirements are:
The base metal to be used (4130, F22 or some other alloy requiring PWHT when welded on)in production for repair
A clad layer is put on
The sample is PWHT
The depth of desired repair is machined into the clad layer
Weld up machined area
Do the bends, macros, hardness and chemistry
If the base metal is reheated enough the hardness will go up and probably fail the hardness requirements.
Thanks,
Peter
Peter
