Stainless porosity

[Hitch]

Something strange i noticed.....the other day, swapped one of the mig plants over to 316 stainless wire. It has dual cylinders on the back, so only wire needs changing.

Swapped the gas pipe over to the Inomaxx, but didnt turn it on, did a couple of test tacks, It didnt get porosity in it like youd expect if you forgot to turn the gas on for steel, just looked a little dull and got the air bubble at the end.

I dont think it was partly gas in the system either, did a few more tacks than that covers.

Any explaination why the porosity is so different...?

 

[Chickenjohn]

Stainless steel is an alloy with chromium (and other metals, CrNiMo17-12-2 316 S31600), these additional metals protect the steel from rusting (oxidising) and what may be happening is they are doing something similar with your tack welding- hence the different behavior.

I would still use gas when welding stainless though.

 

[TechnicAl]

you were lucky