PWHT after Tube Plug Seal Welding

By - Date 05-17-2005 12:01

Kiran,
Whether you are "required" to PWHT should be decided before you ever start your welding. What does your spec require? Using an Inconel wire will give you greater latitude to avoid PWHT if you are not required to follow any specification. Be careful of solidification cracking due to the thickness difference. The 200mm sheet will cool very rapidly during the welding process and can cause cracking. Just a thought..

CM

By MBSims

Date 05-17-2005 22:44

Preheat - yes, PWHT - typically no. But, check the PWHT exemptions in the applicable code.

By Kiran Date 05-19-2005 05:05

Section 8 Div1 para UCS-56 gives exemption from PWHT for P1 materials for similar kind of joint but not very clear for P4 materials.
May be someone can help me on Interpretation part of it.

Kiran

By Bill Mc (**)

Date 05-20-2005 13:44

I agree with CMeadows & MB, and just an FYI-

Since you have referenced ASME 8...
I am assuming that this is a ASME 8 Code'd pressure vessel.

The welding in of a plug to seal tubes in a boiler or pressure vessel is considered a "repair" by the NBIC (National Board Inspection Code). Your State Jurisdiction will very likely require you to have an "R" Stamp Certificate of Authorization for completing this repair, (even if you are the Owner). Before making any repairs --the welding procedure, the electrode, pre and post weld heat treatment, etc would have to be approved by your Inspector. Sometimes called "Authorized Inspector" who is an individual who holds a valid and current National Board Commission, and is employed by an Authorized Inspection Agency...a company like Hartford Steam Boiler.

But i gotta feeling you are not in the States...