I'm having difficulty doing keyhole welding with my wire-feed welder (Millermatic 35, flux-core, .035 and .045 wire). I never had trouble with stick, but with the wire-feed, I can never get the keyhole to form. And oftentimes, the wire extends through the gap to the far side and the arc goes out. I'm doing butt-welds with 1/4" mild steel, 60 degree bevel, with 1/16" root face, and 1/16" gap. I've tried multiple heat settings and wire feed speeds. Any advice is appreciated. John
You can keyhole a butt weld with Flux-Cored-Wired MIG welding? Same sort of control as with cellulosic stick, passing a keyhole along the joint and getting a decent underbead? If so, please enlighten this poor unfortunate as to how you do this. I though FCW welds had to be backgouged and sealed from the other side... Thanks in advance.
That's how I read it also. You just might luck out once and awhile but normally open roots are done with bare wireGMAW, E 6010, E 6011 or TIG You might not be doing the impossible John but you are doing the impractical. Randy
I remember my first attempts of doing an open root with 6010. I thought it was impossible. I have done a 2g caisson test with a 36" pipe, 1.5" wall thickness, FCAW, motor driven, hand manipulated bug, but that had a 6010++ open root first pass.
I have never tried FCAW on an open root, but it doesn't sound good at all.
If anyone has seen it done, done it, or if it is an acceptable root weld, please comment.
I have used FCAW with shielding gas for open root welds both on pipe and plate, basically the same principle.
For the root pass in the 6G position with 0.045 wire, 200 ipm and 20 to 21 volts. Mind you this will vary from machine to machine, didn't have an amp meter available. The joint was made with a 1/8" land and a 37.5 deg bevel, with a 1/8" root gap.
It was easiest to perform the root pass welding vertical down with the above settings.The fill and cap pass where done with the same settings with vertical up progression. The college I was attending was helping a company to perfect the procedure for CWB certification.
Out of four pipes I cut coupons out of only one had a problem with a start that opened up. I sneezed as I pulled the trigger...did nothing to help with improving the quality of the weld LOL.
For welding vertical up required changing to a machine that could run the same size wire but at approx 100 ipm and 17 volts. Not as easy to do and much slower, on par with stick welding.
Locally a welder I know has been using self shielded wire Innershield NR-232 From Lincoln electric for Pipe Piles and is able to complete a piling in about half the time as his father and partner who are welding one piling together. No backing strips for either process in order to cut down on fitting time.
PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.