I dont understand how you can say less chance of breakage. People go on about metal properties and how the heat effects the gear metal. How many of you have actually welded a diff let alone driven a car with a locker? Would be interesting to know.
If you can weld properly and get good penetration with the weld, there is no reason the welds will break. You only need to weld in all four corners on each side. That means there is eight welds plus the gear faces that are still touching, taking all the load.

Tailshafts are made of thin tubing and are welded at each end to a uni. Do you think a tailshaft maker is going to heat a sealed airtight tube to condition the metal? So how does the thin tube right next to the weld that has had its properties changed as a result of the welding survive the twisting torque applied to it.

I know and understand about metal properties, but to say " If you weld a diff, It will fail." Is bull.
Bridges are built out of metal everyday. Structural welds are done on them everyday. Do they heat treat those welds?


At the end of the day. For a street driven car any form of locked diff is only fun for spinning 2 wheels.