Chromoly and stainless steel

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Is tig welding chromoly tubing similar to tigging stainless tubing?  How about backing gas?  Should I be using a low purge flow of argon?  Thanks for any insight.
Reply:Its really no diffrent than mild steel..After all you use a mild steel filler on it don't you?? Treat it the same as mild steel and you will be fine.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Good point, thanks ZAP.
Reply:Don't use backing gas, but drill a small hole in any tube that will be sealed off on both ends.  Failure to do so will cause a blowout right as you finish the bead up, and then you've got your hands full of tricky repair work.The downer is that chrome moly is not nearly as tolerant of excessive heat input as mild steel is.  You will need to move quickly, and staggering your weld can minimize the HAZ.
Reply:Thanks for the gas info.  Will the weld color be similar to stainless or mild steel if my heat and speed are good?Last edited by flatliner; 09-18-2007 at 09:18 PM.
Reply:Just like mild.  Most coloration will be in the heat banding around the HAZ, which is what you should be watching the most.
Reply:Thanks to everybody for the info and taking the time to contribute.
Reply:Originally Posted by SupeThe downer is that chrome moly is not nearly as tolerant of excessive heat input as mild steel is.  You will need to move quickly, and staggering your weld can minimize the HAZ.