aluminium/carbon steel welding

[Cagou]

I have to redesign a 18" T wrench to remove 1 5/8" hex nut head, first think was all carbon steel, but some ask for aluminium pipe welded with carbon steel socket section (!!).
I mentioned the problem of resistance of this heavy duty tool, but I need expert answer for the welding problem.

 

[GRoberts]

Steel and aluminum cannot be fusion welded. Their melting points are too far apart. They can be welded with solid state welding processes, like friction welding, but it may or may not be applicable to your situation.