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Had a weld crack on a 500 gallon tank last Tuesday
We were out at a job site in Gary finishing up a feed water tank for a paper mill. I put a root pass on a seam that looked clean, but after the hydro test we found a hairline crack running about 4 inches. Had to grind it all out and re-weld in 30 degree weather with wind blowing through the shed. My foreman said it was probably from the base metal being too cold, so now I'm running preheat on everything down to 40 degrees. Anybody else had issues with cold weather cracking on carbon steel?
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ray_sullivan5d ago
Preheat's the obvious fix but nobody's talking about the whip technique in cold weather. If you're not pausing long enough on the edges with 7018, you're leaving cold laps that turn into cracks under hydro pressure. I started holding the arc on the sidewalls an extra half second when the plate's under 50 degrees and it cut my crack problems way down. Also check your rod storage, that moisture in the flux can freeze and cause porosity that looks like a crack under the dye pen.
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green.noah5d ago
Had a similar issue last winter on some storage tanks out in Ohio. Was running 7018 on 1/2 inch plate and got a crack right along the weld toe after the hydro test. Foreman said the same thing about cold base metal, but I think it was more about the wind chill and moisture on the plate. Started using a propane torch to preheat everything above 32 degrees and never looked back. Sucks having to grind out a good weld, but better than a failure later on. Hope that paper mill tank holds up for you.
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wren2305d ago
Wind chill and moisture on the plate, really? That's wild. I always figured moisture just meant some porosity, not full on toe cracks that'd show up after hydro. Guess that's why you switched to the torch though, better safe than grinding out a whole day's worth of work.
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