To PWHT or to not PWHT

[Geof]

We have a project using cast Y-strainers, Class 150 and 300, 6" size and smaller.
Material is A352 LCB, rated to -50°F, with Charpy impacts.

Customer has asked for threaded NPT plugs to be seal welded - size 1/4"
Easily do-able, 2 minutes single TIG pass, but: Does this require Post-Weld Heat Treatment?

ASTM A352 - paragraph 9 - Repair by welding. It's not a "repair" per se.
A seal weld is not going to exceed 20% wall thickness, is not a leak repair or defect, and does not create a cavity greater than 10 square inches.

On a pipe fabrication, installing a coupling or nozzle definitely requires PWHT, but I don't know what would apply here.

 

[DekDee]

What is the construction code ?

 

[Dhurjati Sen]

And the service?

DHURJATI SEN

 

[Geof]

They are being installed in a B31.3 piping installation. Fluid is process water.
LCB material is specified.

The strainers themselves are designed per ASME B16.34.

 

[mk3223]

On a pipe fabrication, installing a coupling or nozzle definitely requires PWHT,

Per your statement, is it required by the process?

Per B31.3, A352-LCB doesn't required to be PWHT for typical 150# or 300# Class, unless the pipe wall thickness is >2".