200tdi ayre
Well-Known Member
Answered
MIG Welding Gas Comparison
MIG Welding Gas Comparison
Okay let me make it slightly more clear.
Why does using 100% CO2 when MIG welding cause brittle welds? What is it specifically that the CO2 does or doesn't do?
ok will make it simple. You agree that rapid cooling causes cracking.
What is the temp of C02 when it reaches the air, what is the temp of argon or argon mix.
If you want to research it more go ahead. I'm done
no cracking here.
read ayres'ys link.
CO2 vs Argon/CO2 Mix (1.5mm steel or thicker)
The weld to the right was made using 80% Argon, 20% CO2 shielding gas. It was nice and easy to do. The arc was very stable and controllable and the weld turned out quite neat.
100% CO2 gas was used for the weld on the left. The arc felt much less stable with CO2 shielding gas, and the weld progressed in a stuttering fashion with blobs of molten weld (spatter) being blown off at regular intervals. That's a bit of spatter stuck to the weld about half way up on the left. The arc also seemed slightly brighter than with the argon mix.
marccleave
Active Member
Aren't you a helpful character providing in depth knowledge and answering questions.
:lol:
saw his link. Bead on flat plate simple. Now do a butt joint and then give it the bend test............180degree bend, the thing will snap
will it,you do it and show the result.you said it .
200tdi ayre
Well-Known Member
If a landy chassis bends 180 degrees its ####ed anyway, as is anything else that has been bent 180 degrees. Useless test.
how do you think you get your welds tested when you are in school? Bend test is 1 way
but that is a TEST,nothing to do with the original question,is it.like doing a destructive test,it just shows it is up to a certain standard.
blue beasty
Leaks an prone to bits dropping off
IIRC from late nights study more years ago than I care to remember CO2 is not truly an inert gas but reacts with carbon (increasing it in low/medium carbon steels and decreasing in HCS's) which in theory at least could create a shear point in chassis/bodywork welds.
Higher arc temperature can change the crystaline structure making it more brittle but that's only going to be an issue if deliberating using CO2 to gain extra penetration on welds far deeper than any typical welding done here except perhaps a few professionals.
IMO none of the above is likely to compromise typical vehicle repair work though it might for more complete component manufacture or very heavy duty/high stress applications.
If any experts want to disagree or expand on that I'm very happy for you to do so, as that is dragged from my not always completely reliable memory.
LZ is about sharing what we know to help each other not scoring points, something all of us can sometimes lose sight of.
Higher arc temperature can change the crystaline structure making it more brittle but that's only going to be an issue if deliberating using CO2 to gain extra penetration on welds far deeper than any typical welding done here except perhaps a few professionals.
IMO none of the above is likely to compromise typical vehicle repair work though it might for more complete component manufacture or very heavy duty/high stress applications.
If any experts want to disagree or expand on that I'm very happy for you to do so, as that is dragged from my not always completely reliable memory.
LZ is about sharing what we know to help each other not scoring points, something all of us can sometimes lose sight of.
