PWHT requriement on Cast Valve bodies

[ET1983]

Dear All,

Have come across a query on the need for PWHT on cast body. Need your expert opinion.!!!
However, as per code requirements and per specific client needs, any cast imperfections with weld repairs (or) structural welding of any cast valve component that will be in contact with sour environment shall be followed by appropriate PWHT for its hardness and integrity.

In addition to the above, does the weld overlay / Stellite coating on valve internals be applicable to PWHT?

ELVT

 

[SJones]

There will be three considerations to answer your question regarding overlay and hard facing, assuming that you are addressing carbon steel castings:

1. The pressure design code of the valve parts in question (bodies are typically ASME VIII, Div 1) and its requirements for PWHT

2. For the overlay, will the end user accept the get out waiver clause in ISO 15156-2, A.2.1.5., b)

3. A sensible end user will consider the hard facing as porous thus exposing the carbon steel substrate to the sour fluid. Therefore, they are highly likely to require PWHT if you can't keep the hardness at the correct level

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.