I finally tried a different preheat method on some 2-inch thick plate last week.

We were welding up a patch on a boiler drum in the shop, and instead of the usual torch, I used the furnace to bring the whole piece up to 400 degrees. The weld went in way smoother with almost no spatter, and the post-heat cool-down was a lot more even. I think the steady, full soak did a better job than a local hot spot. Has anyone else tried a full furnace preheat on heavy plate like that?

3 comments

3 Comments

gibson.seth2d ago

Nice. That's a smart way to handle it. Did you notice any difference in how the weld color looked after it cooled? I've always wondered if a full soak changes the oxide layer compared to a torch spot heat.

taraw772d ago

Didn't someone say a slow cool gives a thicker oxide?

sageellis2d ago

Yeah, a slow cool absolutely builds up a thicker oxide layer. I let a piece sit in the kiln until it was just warm to the touch last week and the blues were way more muted and milky. @gibson.seth is onto something with the full soak versus spot heat, it gives that oxide time to really grow.