I've been lurking here for a while and just signed up to throw my 2 cents in recently. So now that I'm here (and to head off any ideas that I don't learn something new every day), I have a question for some of the more experienced welders.
I'm sure that almost all of us have encountered broken die-castings. Not unusual since some have a ductile-brittle transition temperature not far below room temp. Has anyone got any tips/tricks for welding die-castings of high zinc content alloys like Zamac (ZAMAK)? I tried once some time ago... TIG welding/argon/various tungstens/polarities/etc and all I got was a crappy weld because it would pop and spit out metal before I could even develop a real puddle.
I assume it was the zinc vaporizing before the other stuff (Al/Mg/Cu) was even halfway to their melting point. Being unable to weld inside of an atmosphere of 20 tons per square inch to keep the zinc from volatizing, I gave up. But I revisited this question last week when someone brought a GM tilt steering column to me that cracked when the 4 bolts deep inside backed out and let the wheel thump back and forth.
I know this stuff used to get soldered with a special Cadmium alloy solder (EXTREMELY dangerous/toxic) but that's out of the question. Anyone recommend different gas, particular tungsten, AC squarewave, AC sinusoidal, particular balance, glovebox atmospere?
I'm sure that almost all of us have encountered broken die-castings. Not unusual since some have a ductile-brittle transition temperature not far below room temp. Has anyone got any tips/tricks for welding die-castings of high zinc content alloys like Zamac (ZAMAK)? I tried once some time ago... TIG welding/argon/various tungstens/polarities/etc and all I got was a crappy weld because it would pop and spit out metal before I could even develop a real puddle.
I assume it was the zinc vaporizing before the other stuff (Al/Mg/Cu) was even halfway to their melting point. Being unable to weld inside of an atmosphere of 20 tons per square inch to keep the zinc from volatizing, I gave up. But I revisited this question last week when someone brought a GM tilt steering column to me that cracked when the 4 bolts deep inside backed out and let the wheel thump back and forth.
I know this stuff used to get soldered with a special Cadmium alloy solder (EXTREMELY dangerous/toxic) but that's out of the question. Anyone recommend different gas, particular tungsten, AC squarewave, AC sinusoidal, particular balance, glovebox atmospere?
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