Getting MIG penetration, root/corner fusion

In my experience I find that to be backwards. Yes the wire speed needs to be high enough to provide enough amps but putting at the top of the range can cause you to travel to fast for good fusion. This is especially true on the small 110V migs.

There's been a lot of arguments both ways on this group. Personally I don't think the angle as important as the location of the arc in the puddle. If you're arcing toward the rear of the puddle then you're not going to get good penetration. Near the leading edge will give you better penetration.

I usually see that with too much or too little heat which of course is also tied into run speed.

Wayne Cook Shamrock, TX

I use straight on or slightly forehand when running a fillet with hard wire. I have found back hand works best with flux core. In both cases keeping the arc at the leading edge is important. 45 degrees and one wire diameter up onto the vertical is ideal. With three passes I tend to concentrate in burning in the corner and not worry about size. A small bead right in the corner ensures that I have a tie in. The second bead is a flat weld on top of the first to create a ledge for the third. I concentrate on fusing the corner bead to the horizontal plate and the end result covers the first bead. The third bead is another fillet in the corner right on top of the second. After watching several robotic wire feed set-ups I am convinced that a smooth steady gun motion is not the way to go. Some sort of motion to stir the puddle and fuse the edges is needed. If a robotic arm has a secondary motion programmed in then there must be something to it. Randy

I need to improve my fillet corner fusion. Am back to college tomorrow and need to know what to do. My h-v (horizontal-vertical) T-joint fillet weld (3runs on 6mm (1/4inch) plate) was only just passed and really says "you need to understand a lot more". (Vertical) plate edge too visible.

Found this thread on Google archive of s.e.j.w.

- only just avoiding stubbing - for good pen. I have heard too high voltage (for the w.f.s?) can cause metal to "pour" onto weld zone without fusion, despite general association of higher voltage with more heat(?).

Same post suggests "drag angle" on MIG torch for good pen. - which you will always want root-running plate steel welds... ("push angle" for restraining pen./ burn-through on thin sheet?)

And furthermore, suggests round weld pool is right and a good sign - too long = too fast and too wide = too slow run speed.

Particularly wondered about the "drag for good pen." suggestion...

???

Thanks in advance

Richard Smith