cooling tig welded304 stainless pressure pipe with spray bottle

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by mark
(calgary)

I am doing a job with sch 10 304 stainless pipe which is
pressure and 100% xray it gets hot while I am tig welding a welder told me to cool it using a wet rag or a spray bottle which does not seem like a good idea to me will it make the weld crack or any other problem?

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Hi Mark, good question.
I worked a Dept of Energy job fab shop where each work station had a water mist contraption that mixed compressed air with water to cool stainless pipe welds. All those welds were x rayed and as far as I know the air/water cooling did not pose a problem.

Its best to use distilled or demineralized water.
to avoid chlorine etc. but as far as cracking goes, 300 series stainless will not harden from quick cooling.

a spray bottle is a pretty good idea because you can use a fine mist for more even cooling.

And keeping the joint out of the too hot range can help on corrosion later down the road .

Some stainless welds that get hot and stay too hot for too long lose corrosion resistance from being sensitized. ( chromium and carbon combine and cause chromium depleted areas...technical term is carbide precipitaion).