[mdmainat]

Dear Welding Experts,

What is Welding discoloration Acceptance Criteria ?

which code we have to refer for discoloration Acceptance Criteria .

Regards.
A.J.khan

[TheExpert]

Discoloration is oxidation. It is just a matter of the argon shielding envelope leaving the hot metal before it has a chance to cool enough to not oxidize. That is why gas welding steel with an oxyfuel torch looks so gray all over. If you were to use a really large tig nozzle, things would improve. There are also other ways to accomplish the same thing, watch your heat input, use a large nozzle, use chill bars to suck the heat out quickly, or stop often to let cool. Also you may be a little too concerned about penetration. Most of your welds on headers are fillet welds with maybe a few laps and butts. Stainless has a tendency to bond really well with low heat as long as it is clean. Unless your beads look really cold and ropey, you are probably ok. Since you mentioned that sometimes you get good luster on your stainless welds, I think we can assume that everything is working ok. but just to make sure.....