heat treating metal bits?

[vrooom]

Has anyone done the heat treating the metal bits (only steel items) on car like diff output, propshaft, axles, etc to make it more wear resistant?

[mattr]

I've seen mention of it being done on other forums.
rctech maybe?

Few issues around it though, you might make the parts brittle, you don't get them hot enough, or cool them correctly, and end up worse off than when you started!

And you don't always know what grade of material you are dealing with......

[mattr]

Might distort the parts too

[mattr]

Except the solution that the manufacturer used.....