Welding between different metals

Hi
Can anyone give me good technicaal info for welding between : A. stainless steel and Galvanised steel B. stainless steel and aluminium C. aluminium and galvanised steel
??
TY

Doris Pang wrote:
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sci.engr.joining.welding
HTH
Michael Dahms

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Don't

Doris Pang wrote:
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sci.engr.joining.welding is really the right place, but -
A. Galvanized steel = plain steel + zinc coating. Grind off the zinc (you have to do that anyway, don't want to get metal fume fever from the toxic gasses), and weld with the appropriate SS filler.
B. Explosion Welding, or something else suitably exotic. Not going to happen with any of the arc processes.
C. See B.
Best way to join is with mechanical fasteners (bolts, screws, rivets) and some sort of appropriate isolation material between the aluminum and the steel.

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On that subject, I've a piece of scrap metal here that rather puzzled me. It's a few feet of 4" diameter Ti tube - with end flanges of a magnetic stainless steel welded to it ! Any thoughts on how that might have been made ? It's aerospace, so expensive exotic processes are entirely possible.

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I've seen something like that in a heat exchanger that cooled corrosive fluid. Are you sure it's a weld (does it look like an arc weld)? It could be sprayed (cold, plasma?), explosion or friction welded, I guess.

Andy Dingley wrote:
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Could be something exotic like laser (or one of the energy beam processes) or something as mundane as brazing. Given, it's some pretty special brazing, but that would do it.