My gas supplier keeps insisting that argon/CO2 is the best gas for my Millermatic 130 MIG welder and it does work pretty well on tube but I am getting some under cut at the edges of the bead that is a pain to grind out. Now I have some 3/16" stock that requires a lot of Tee joints. I need to get my bead to flow out a bit more to make grinding a fillet easier. Would a helium/argon mix work better?
Which gas for 316?
May 04, 2004
7 Replies
Only if you were trying to run aluminum.
For steel you want Argon/CO2/Helium, Aregon/CO2/Oxygen, or Argon/Oxygen. The first 2 are tri-mixes, and are both very good for stainless steel
98/2 argon/oxygen is even hotter, and is used for spray process on steel.
Not sure I understand. Linde "Stainless Tirmix" is 90% He 7.5% Ar and
2.5% CO2. I tried a little of it on the welding supplier's 210 this afternoon and it laid a nice smooth bead with no undercut. Is there a corrosion problem or something?
No , but stainloess steels usually have a heavy oxide layer when MIG welded. Tri-mix gasses burn hotter and reduce the the oxide layer left after.
On Tue, 04 May 2004 23:14:45 GMT, Ernie Leimkuhler vaguely proposed a theory ......and in reply I say!: uncap my header address to reply via email
Ahah!. I was just using some stainless wire to weld dissimilar metals (weldall wire) using Qr/CO2 and noticed the black layer. It came awy very easily.
But could it be a problem if I welded over the top?
I did notice that it was sometimes bad enough to stop proper arc starting, but once the arc/process was underway it seemed to cause no problem with the actual laying of the weld.
******************************************************* Sometimes in a workplace you find snot on the wall of the toilet cubicles. You feel "What sort of twisted child would do this?"....the internet seems full of them. It's very sad
You can always mechanically remove the oxides after welding.
On Wed, 05 May 2004 08:03:57 GMT, Ernie Leimkuhler vaguely proposed a theory ......and in reply I say!: uncap my header address to reply via email
Interestingly, the stuff I am using "self cleans" in a short time after I weld. Say an hour later, it's all shiny.
But I was more wondering if laying down another layer over the top straight away, without cleaning, was a problem, in the way that slag is on stick welders.
******************************************************* Sometimes in a workplace you find snot on the wall of the toilet cubicles. You feel "What sort of twisted child would do this?"....the internet seems full of them. It's very sad
I would not recommend doing that if you want the welds to be clean and rust free.
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