PWHT temporary spool

weld7777 · Nov 13, 2014

Gentlemen, P-1/P-1 BW, .sch80 16". B31.3, requires PWHT. To pressure test, spools need weld caps at FW/FA locations, with PWHT previously performed on all other welds on the spools, 1hr hold. Would I consider PWHT on the temporary weld cap that will be cut off and no part of the actual system. Yes I know about plugs, but fittings . Looking for experienced response please.
So I guess the question is would "YOU" and why?
Thanks Guys

weldstan · Nov 14, 2014

Sound welds in low carbon steel pipe can readily be made without PWHT. I would not PWHT the temporary welds.

pennpiper · Nov 14, 2014

weld7777,
Unless I am completely wrong I was under the impression that PWHT of welded joints is not just for the weld but also for the HAZ (Heat Affected Zone) on both sides of the weld itself.

A butt-weld creates a HAZ on both sides of the weld. When you 'Burn' off the Cap (or other object) it also creates a HAZ.

If your WPS (Weld Procedure Specification) calls for PWHT then you might want to discuss any deviation with you AI (Authorized Inspector).

Sometimes its possible to do all the right things and still get bad results

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PWHT temporary spool

weld7777

Industrial

weldstan

Materials

pennpiper

Mechanical

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