welding...metal is brittle....any idea why?
B..een welding up the pin holes on my dart's roof at the roof rail. Drilled the spot welds to get the donor roof off. Used a 5/16 spot weld bit to get it done......2 people put my roof on at the factory. One was sober and made perfect welds.......the other was drunk and decided to drag the spot welder making long welds.......in drilling these drunk welds out I got very close to the rail and someimes even into the rail. This left no flat area to reweld the roof back on to the car.
I built the metal up some but when I gound it back down to shape it it cracked because weld with the mig is brittle and sheetmetal isn't work hardened.
How can I get these flat spots back to weld to the roof without it being brittle......I'm using a lincoln mig 140 with wire speed 3 and heat on setting c. Can I reverse the brittle effect of the mig. Maybe by anealing