Welding of Hot rolled and A-36 plate

By jer

Date 02-02-2005 18:14

I was wondering if the scale should be removed prior to welding, by grinder at weld location or sand blaster. What are the ups or downs to welding over scale?
I recently bought some metal core wire which should dig deeper into material. The thickness is usually 1" HR or A-36 plate welded to a 1/2" thick tube of various dimensions.
Should all weldments be stress relieved? Some customers call for it and some don't.

Thanks

By Skiddy

Date 02-02-2005 19:51

Are you using any code? ASME requires you to clean at least 1/2" from the weld grove. If you don't clean it you can have porosity and other discontinuitys. As far as heat treat some customers here at our work some do and some don't. Hope that helps some.

By jwright650 (*****)

Date 02-02-2005 20:38

Welding over mill scale... well, probably will experience some undercut at the toes of your fillets. I say this because it takes more heat to melt through the scale than it does to melt the steel under that scale.
Depends on how thick the scale is on your material. With FCAW, really light mill scale shouldn't be a problem at all do to the digging characteristics. GMAW (metalcore) on the other hand doesn't like mill scale at all, (in most cases) at least that's what we've found here in our shop.
John Wright

By jer

Date 02-02-2005 22:11

Thanks guys for the feedback. Just starting to make these bases and I will grind scale at weld area.

By jer

Date 02-04-2005 19:50

Hey guys is there a difference in metal or weld strength when using plate or HR?

BTW where can I get the ASME book ? and what does it cost ?