Welding Tips and Tricks

Welders have been failing X Rays due to too much porosity in welds. We have eliminated everything we can think of to stop the porosity. Any suggestions on Mig wire to use? We are welding on 1/4" stainless steel, 1/8 " weld gap with one side of joint beveled. Welding root pass in from inside, grooving out from the outside then hot pass and cap (hot pass only on head of tank due to being a little thicker). Currently using ESAB 308lSI. Wondering if the Silicon could be causing the problem and should switch to Blue Max 308L?

I've never been impressed with ESAB consumables. A wire switch is a good start.
Contaminated gas is another possibility--moisture, or inadequate purity.

Let us know what works.

Steve

Thanks for the reply Steve...
We ran some test plates with a certified bottle of gas last week with about the same results. We are going to run some test plates with a different wire today and have the xray crew shoot them while they are here next week. Ill post the results. Any more suggestions would be appreciated.

I've had challenges with ESAB's 6010/7018 rod, mainly inconsistent flux causing arc-wander and difficulty mantaining a close arc witout sticking. Their E-70s-2 MIG wire was difficult to dial in to minimum spatter and had inconsistent burn (the arc-legth would vary). None of this was X-ray work, so I can only guess as to the internal quality of the weld.

In the first case, I was able to convince the boss to switch to Lincoln rod, and productivity went up about 25%. With the MIG, I just had to bite my toungue and cuss quiety while cleaning the welds.

Your theory about the silicon sounds valid. Left behind as micro-inclusions, it would appear as porosity in a radiograph.

Steve S.