Was working on a trailer hitch ball holder, welding 1/4" material mild steel, using 1/8 7018 at appx 150 amps and the "dig" was set at 100%. The first half inch of bead had pin holes, but then smoothed out all nice pretty. I did clean the metal prior to running the weld, but a little paint may have been present here and there. Anybody know what's going on here????
Thanks,
Nils
Several things may be at work beside the paint (or other) contamination.
>The rod was cold and maybe damp. As it heated and expelled the water it smoothed out.
>The metal was cold and heated up to give better smoothness to the weld. Try preheating next time.
>The rod was long-arched at the beginning. As the weld went along the stick settled in to the "contact" mode.
>The rod was cold and maybe damp. As it heated and expelled the water it smoothed out.
>The metal was cold and heated up to give better smoothness to the weld. Try preheating next time.
>The rod was long-arched at the beginning. As the weld went along the stick settled in to the "contact" mode.
150 amps is way to hot for 1/4" material. Try backing that off to about 90-95 then warm up the rods in front of a heater or something. 7018s need to be dry at least but warmed up helps a lot too.
Be the monkey....
- Otto Nobedder
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Nick's right. Straight from a new can, 1/8" 7018 is RARELY run above 120A, I usually run 105-110, with dig (when available) around 70%.
7018 left to nature is an unpredictable animal in any circumstance.
Ever weld a damp 308 or 309? 3 or four inches and "boom", the flux explodes. Bursts right off.
7018 left to nature is an unpredictable animal in any circumstance.
Ever weld a damp 308 or 309? 3 or four inches and "boom", the flux explodes. Bursts right off.
I think the OP stated the obvious in his post. He started the weld off with paint (contaminants) on the surface. Who knows what else existed on that joint near the beginning of the weld. An oil based paint really jacks up 7018, unless its completely removed. Any paint on the surface regardless of paint type, makes havoc for 7018. I do agree that 150a is too high, but that's not going to cause worm holing. Long arcing and paint contamination is more than likely the culprit.
"Let's light the fire an' brief on guard.". RIP Lt. Col Stan "Red Dog" Nichols. USMC. Fighter Pilot. Korea, Vietnam. MCAS El Toro.
Pin holes often happen when re-lighting a partially burned 7018. 7018's do not have a lot of arc force and take a second or so to get warmed up. If the welder has hot start then turn it up. If not then long arc the rod for about one second and then settle in to weld. File the end of a partially burned rod and it will light much easier and help with the pin holes.
Kevin
Kevin