Welding Tips and Tricks

Ok guys question here.

I'm currently building a project that requires us to mig pulse on 1/4" stainless.

When I originally showed up working here these guys was running (.045) 170ipm on wire speed and arc length any where from 60-75. We could just not get travel speed up with a wire that size and when you tried to move faster at that wire speed setting the weld would keyhole on the back side of the weld like it wasn't being given enough time to fill. Our new boss ( not a welder) kept asking what we could do to speed up the weld process.

So I call miller and talk to Rick ( one of miller's welders) one Friday on my own time after work to figure this out. Rick told me that the wire speed was too low and we needed to be running anywhere to 400-450ipm which scared me do to on pulse when you increase the wire speed the machine automatically ramps the voltage up.

On Monday I go back to work and instantly set the machine at 380ipm and arc length at 55 and sharp arc back to 25 like was recommended by miller. Instantly I had my travel speed and doubled production but the weld color was gray and not a blue bronze. I now find our this project will be being inspected by a CWI and may not pass his inspection because the parent metal could have been compromised and weak due to over heating the weld. (The equipment I'm using is a Miller Invision 352MPa and D-74MPa Plus feeder.

I asked Miller about needing the color in stainless and Rick tells me that on 1/4" stainless I should not worry about achieving this "color" or would even get it.

We have built several of these Items and now worried they could be rejected because of this.

I'm also thinking .045 wire is way too big to be welding 1/4" material and need to step it down to .035 to try and not need to weld as hot to get the wire to fuse.

I'm totally lost and I've contacted the company owner (the type of guy most of the pee on's don't contact) to express my concerns via text and what I was told by Miller. He calls me on the phone on yesterday (yeah on the 4th of July) while he was on vacation. I'm hoping I didn't step on my D*ck expressing my concerns to the company owner but the new boss wanted to ramp up production which I did but might have compromised the integrity of the parent metal doing so.

Now on Tuesday I have a meeting with one of the company suits, our new boss and our other welder to figure out what we should do.

Any help on this would be great guys because the amount of product we might have to scrap out could be huge money.

I'm just trying to get this issue resolved but the company owner said if we cant get this figured out we would bring in our Miller tech in to try and help us get this figured out and thanked me for my concerns and being so conscientious about making our product the best of the best.

Shannon

Shannon,

A demonstration piece I did for our "R" stamp (which was x-rayed and visually inspected) had a WPS calling for .035 spray-arc in the 250-280A range. The weld itself was discolored, and would not get fully shiny with aggressive wire-wheeling, but the HAZ cleaned up nicely and the piece passed.

This was 1/4" 304 plate, open root, with ceramic tape backing. I did two passes, though I had the option to do a single in the WPS.

I suspect your welds will be fine.

I doubt you stepped on your d!@k, since you got that call. It might be worth it to weld a sample piece in the same fashion and take it to a CWI for analysis using whatever method the parts must pass (cheaper than bringing him to you), and maybe make a coupon for in-house destructive testing.

Just some thoughts.

Steve S

Thanks Steve.

These are on mostly corner joints that are on a frame set. I was afraid that at 25v and 380imp I could be overheating the parent metal.

Shannon