Quote:
Originally Posted by opnwhlmnd
Because it's 4130 chromoly and most do not weld it properly. Cooling too quickly causes embrittlement and you see the breaks away from the weld joint. It also needs to be preheated to at least 80 degrees before the weld process, I like it even hotter than that. Ideally we would have an oven to preheat it do the welds and then back in oven to post heat.
I'm not an expert but when in welding class many years ago that is what they taught me and I never had tubing failure on any chassis I built or repaired.
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I'll second that theory, I didn't preheat, but I did an operation called purge welding, where you run another hose thru the tube, and send in argon to the inside, and it makes the joint look inside, just as clean as it does on the outside, it is a requirement on anything in the medical welding process. I've not had a weld crack either, it works. If a guy had a powder coating oven, that would be about the right temp, I always felt powder coating returned the moly back close to it's original heat treat. Bob