Hi Colby!
I would'nt recommend the water squirting technique right after the joint has been welded because of the O2 in the water or the rapid cooling which will cause some detrimental metallurgical effects to both the weld and the HAZ... Electropolishing or passivation is necessary sometimes.
The oxidation can be minimized or even eliminated by using a trailing shield and the biggest cup like Brande suggested. Passivation/pickling can safely remove any minimal amount of discoloration so long as it's accessable and in situations where it's not, then either passivation or electropolishing is used to ensure corrosion resistance like Nieke3 mentioned. In some cases like in UHP (ultra high purity) applications, the purging CFH is raised up substantially... Very expensive for the contractor but, very profitable for the supplier!!! After this electropolishing or passivation is performed and is also expensive but, worth it in the long run...
I wonder if it's an orbital welding application on bioprocessing systems since the person mentioned that the welds are autogenous? Hmmm...
Respectfully,
SSBN727 Run Silent... Run Deep!!!