So, if it was YOU welding this, what would you do?

[Gerry]

I don't think it makes much difference what you weld the bracket together with, I'd be more worried about the trailer tongue
bending. 9000 lb straight line pull on a tube (tongue) only being secured on 1 end ?. But then again, we didn't see the trailer your mounting the bracket on.

[jakeru]

Chris, check this chart out:
http://www.ckworldwide.com/tech-3.pdf
(Note that the listing for "thoriated", generally applies to lanthanated/ceriated as well.)

It says, 3/32" tungsten, DCSP, thoriated = good to 250 amps. Although, 1/8" with a pretty long taper grind would I would think would work well also. Using the right diameter tungsten can help with better control of the direction of the arc. It's more an issue with AC I think than DC, but if you did notice the arc was ever wandering off one of the tip of the tungsten versus the other (especially if it was going a direction you didn't want it to go), then smaller tungsten would help with that and keeping the arc going straight forward off the tip of the tungsten. I'm guessing that wasn't really an issue, but, worth keeping in the back of your head when it happens, you can know what may be causing it.

And yeah, it's definitely good to set more than you need at the footpedal, so you have some "throttle in reserve." You really don't need to be too precise with setting the footpedal max current, as long as you don't get too little, your foot can always compensate. But your foot can't press down more if you don't have enough.

I would have set the amps to the max, and, if you had more than you needed, I would have dialed in a little pulsing. (Low-frequency pulsing, for reducing heat input. Maybe something like a 50-70% background and 50-70% pulse duty, and 1 pulse per second.) If it were my Super200P, I'd definitely have had pulse turned off though. It can help reduce heat input though.

It's hard to say what the voids were caused by. I'm guessing it is some kind of contamination. Was the surface of the puddle kind of "boiling" as you were welding? It is important to clean the back side, if you are fully penetrating. And in this scenario, shielding the back side (like back purging) might have helped, but I certainly wouldn't have bothered with something like that for a project like this. If it were stainless though, you'd have wanted to do it. I'll bet that weld is strong... Steel penetrates like crazy. It is not hard, any welding process to get it done. Any oxides, melt at a lower temp than the base metal, and just float to the surface. Much more forgiving than welding stainless, or aluminum.

Anyhow, I'd say it's pretty decent. It's actually good not to overpenetrate into the receiver part, you don't want that to warp so that the receiver still fits. I'll bet you got great penetration though. Actually what you did looks great. It looks like you prepped it well enough (for what it is.)

"boxing" the joint will add a great deal of strength and rigidity.

Torch angle I am sure is something that you should be thinking about... too far "leaned over" to the side = can draft atmosphere in. Pointed totally straight down, doesn't really pre-heat the metal for adequate travel speed. There is a happy medium of "just a little bit" of torch angle (just a little bit off totally vertical.) There is another problem with angled too far, too much heat gets pushed over to your filler rod, and can make it melt before you get it into the puddle, causing an erratic amount of filler being deposited along the length of the weld bead.

Also, be aware that argon is much heavier than air, so visualize it as "wanting to fall." It doesn't work quite that great with the torch pointed sideways with a ton of tungsten stickout, but you can run a ton of tungsten stickout if you have the torch pointed straight down (Horizontal joints = really good shielding with argon.)

If you mix is a touch of Helium, I find that you can weld more sideways, or really in any direction, with lots of tungsten stick-out. I haven't tried running Helium on some thick steel, but I want to sometime. It does allow a smaller tungsten, more intense heat. Helium has a property of conducting away heat better than Argon, so it cools the tungsten and collet body, etc and lets you run smaller diameter tungsten. Only downside is a bit extra cost for the gas.

Usually, the way to reduce heat input is to weld "hotter and faster". But you want to maintain control and to that end, I'd say best thing for you to think about is to try to be more conscious of your torch angle next time. You don't want to go so fast you lose control. If you can get your filler rod feeding hand working to pump the filler out as it is needed, that can be fun, on longer joints. Before you learn that, you will find you are needing to stop the arc to reposition your filler rod on the rod, then, start the arc again.