Tried a different preheat method on a 3-inch thick A516 plate in Buffalo

We were doing a big repair on a boiler drum and I decided to try a stepped preheat instead of our usual straight ramp to 350. I set it to 200 for an hour, then 275, then finally 350. The weld puddle was way more fluid and the bead looked smoother than anything I've done on that thickness before. Has anyone else played with stepped preheats on heavy plate?

4 comments

4 Comments

anderson.taylor2mo ago

My buddy swears by that method for thick stuff.

phoenix_singh2521h ago

My buddy Steve was in the middle of welding up some heavy trailer hitches last year, thick steel plates about a half inch. He was fighting with it for days, getting slag all over the place and having to grind down nasty pits between passes. Then he tried that slower travel speed with a tight arc, and @daniela85, the bead came out so smooth you could almost see your reflection in it. He called me up all excited, said it cut his cleanup time in half because he barely needed to touch it with a grinder. That one change of method just saved him hours on the next big job.

daniela852mo ago

That smoother bead you saw totally sells the method.

linda_reed2mo ago

Oh yeah, a clean bead is the best proof. It shows the heat and travel speed were just right. In my experience, that's what keeps you from having to go back and fix a bunch of pinholes later. Makes the whole job go faster.