New Brunswick, Canada | Many rear ends are cast steel.
Problem with cast iron is its got no ductility, and its got enough excess carbon to make mild filler rod brittle too. When the hot bit cools it shears/cracks away from the cold base. Pre-heating A LOT will let the object and the bead shrink together, but it takes a ton of pre-heating, the hotter you can get the cast the less differential shrinkage there is.
Peening mechanically expands the weld as its trying to shrink to offset the stress.
Other approaches you can sometimes build a little pad of spot/plug welds with MIG let it cool, then build again, cool. End up at the top of the pad with fairly low carbon content you can weld to.
Brazing works pretty reliably.
Tomsaw - 2/3/2020 20:54
Wanting to tig weld a steel top onto a cast iron base . My son's friend says that he uses a regular steel tig filler rod on cast rear end housings with no problem . When they were welding it tonight the welds were cracking . Any ideas ? I have always used a nickel rod in the past to weld cast iron . |
Tig welding cast iron
