ASME weld repair

[3lilaggies]

I am looking for code reference to weld repair a cast body according to ASME code. UW-38 doesn't list anything like what would be considered major or minor like in TP278 (MIL-STD) Can anyone help me out.

 

[metengr]

For valve body or pressure retaining castings, I would recommend ASME B&PV Code, Section VIII, Div 1 for preheat and PWHT guidance and qualify the procedure and welder to Section IX of the ASME B&PV Code. Also, NDT requirements can be followed per ASME Section VIII, Div 1.

 

[chicopee]

I am not sure that it is a good idea to weld repair castings better replace it.

 

[metengr]

I am not sure that it is a good idea to weld repair castings better replace it.[/quote chicopee]

You have got to be kidding. This is routinely done on pressure retaining castings in most major fabrication shops.

 

[GRoberts]

Most large cast steel bodies will have weld repiars straight from the foundry. If castings couldn't be weld repaired, you wouldn't have many castings. Cast iron is a different ball game though. What type of material is the body?

As Metengr states, Section VIII is a good reference for repairs. Weld procedure qualification is no different for repairs per ASME IX than fabrication welding, with the possible exception of temper bead welding, which is often used for repairs, but can be used for fabrication as well. The only definitions for commercial casting repiar sizes are in the ASTM material specification, but a field repair would not need to comply with the ASTM specification, but it would be a good guideline.

 

[chicopee]

I accept the fact that foundries may do welding repairs but only on minor damages. If the casting is to be used for high temperature and pressure, I doubt that foundries would perform the welding repairs on major damages.
To repair major damages on casting can be catastrophic as you are all aware that casting is far from being a perfect material--better eer on the cautious side than the frugal side.

 

[GRoberts]

Most ASTM specifications address the size of minor vs major weld repirs, but none of them prohibit major weld repair. They sometimes add extra requirements, such as PWHT. Major welds are repaired on castings all the time. Many castings, including high temperature, high pressure castings, have through wall repairs by design, when access holes or core supports are needed. I agree that castings can be far from perfect material, thus the need for welding when higher integrity is requried than the casting provides without the repair. Castings I am familiar with average about 1-2% replacement of their volume with weld metal repair. If you have a 20,000 lb body, 2% of the castings is 400lb of weld.