Why does every new guy ignore the preheat on thick plate?

I keep seeing rookies try to weld 1 inch plate without any preheat and wonder why their beads crack. My old mentor told me last month that anything over 3/4 inch needs at least 250 degrees or you are just asking for trouble. Has anyone else noticed this on job sites lately?

2 comments

2 Comments

craig.nathan1d ago

My buddy Mike out in Ohio tried to weld a 1 inch thick flange for a pressure vessel without any preheat last year. His foreman told him to get it up to 300 degrees, but Mike figured he could skip it because he was in a hurry. First bead looked fine, but by the time he started the second pass, he had a crack running the whole length of the joint. He spent the next two days grinding it out and redoing it with proper preheat, plus the boss wrote him up for wasting shop time. Your mentor was dead on about 250 degrees for anything over 3/4 inch in my book.

andrew_sanchez941d ago

Man, that's a brutal lesson to learn the hard way. Feel for the guy, but at least he'll never skip preheat again.