Dark Bead

[OSU-WE10]

I currently getting very frustrated with some stainless wire that I am working with. I have welded on the same 304 stainless plates before, 1/8" and 3/8" thick 2"x6" plates, using similar wire but I cannot seem to get a good bead with any settings. The data sheets for the wire that I am using, McKay 308/308L 0.035 diameter, state the ranges as such:

For spray transfer using 98/2 Ar/O2 gas: 23-26 volts, 150-225 amps

For short-circuit transfer using tri-mix (90 He, 7.5 Ar, 2.5 CO2): 14-22 volts, 60-200 amps.

I have run the spray transfer with voltages from 24-30, amps from 150-220 (WFS from 300-490) and cannot get a consistent bead that isnt dark grey. I know that when voltage is too high you get this color bead, but I get it even at the low end of the voltages that are needed for spray. I tried going to lower voltages, but after 24 I am getting into a gobular transfer. I have welded with the same type wire with these settings and had much better results, so my only conclusion so far is that theres something wrong with the wire. I have also experienced a type of fluttering in the feed when I turn it down towards lower settings.

I figured I would try it with short-circuit transfer just to see if I could get a decent bead but got similar results with a dark greyish bead. I am still doing some adjustments here to see if I can get anything that looks like what I had on previous stainless steel wires.

I am currently just testing out wires but before I make my final evaluation I was wondering if anyone had any suggestions.

Thanks,
Nick

[Hobart Expert Bill]

The dark (grey/black) color is an indication of lack of shielding before the metal has cooled enough the surface of the weld bead oxidizes, in most cases with spray arc on stainless you will get a little darker color due to the heat input.

[Rocky D]

The thinner material will not chill fast enough to get the golden brown color...I have never seen the color lighter than that , and then only on thicker material...I welded 1/4" to 3/8" and was able to get it, because the bead would cool faster due to the thickness of the metal, and I was doing a weave, not a stringer bead. Even though dark, you can wire brush it to look nice.

[Rocky D]

The thinner material will not chill fast enough to get the golden brown color...I have never seen the color lighter than that , and then only on thicker material...I welded 1/4" to 3/8" and was able to get it, because the bead would cool faster due to the thickness of the metal, and I was doing a weave, not a stringer bead. Even though dark, you can wire brush it to look nice.

The cooler you run it, the better your chances of getting a lighter bead...real difficult on 1/8" stuff, tho.

[OSU-WE10]

Thanks for the replies. I will try to run a little cooler and maybe with a slight weave. I was just stumped because I had used all the same settings and plates with a similar wire and had much different results.

[OSU-WE10]

Well it might have been the stainless that I was working on. I didn't notice at first that it had a thin layer of some kind of film on it. Cleaned it up and tried again, much better results.