when ive seen them fail it was not the weld, but the base metal and placement. they were just welded on the face and under side load ripped the base metal along the heat eff. zone.
yes at a staight pull 3" of 7018 will hold 300,000 (ive done it), but under side load you are banking on the heat eff. zone (right next to the weld) holding.
wich after hydrogen imbritlement is only good for about 4000 draw, and less than 1000 of torque load on 1/4" mild steel.
if i would have used mig, all of these # drop by 40%
by running three sides and useing an open root proc. i know that this bumper will never fail, no matter what.
if some jackass hooks up to him in a mud hole and runs 40 mph to the end of a 100' stap sideways, no one is going to be wareing part of a bumper i built as headgear.
and sence you have been working in the biz for so long you will under stand how qualified i am in this area better than most (or you should at least)
im a pipe welder in the oilfield, when i get called to a job peoples lives depend on me doing it the right way