This might help, might not. Most of the old junkyards used to fix broken leaf springs on equipment. They break in cold weather. The guy who would weld them up would heat with a torch, weld with a stick and cool them in the nastiest dirty diesel oil you ever saw. They would do it again if the color was not right when you grind on it. They always welded up the grind marks, quench it one last time and bury it in ashes overnight to cool. It must work or they would just replace the spring. I know where some are still in service thirty years later. Not working now but not cracked either.
Edit
Wrong thread. Move it please to the raffle