i will add you CAN'T MIG WELD on UHSS, ultra high strength steel. you have to use a squeeze type resistance welder, STRW, that duplicates factory spot welds. this includes welding the UHSS panels themselves and welding panels to it.
i will clarify this a little bit. as of now, you can mig weld the mounting flanges of UHSS. mounting flanges are what's under the weatherstrip. you can weld these areas but you are strongly suggested on using a STRW. if the area is panel bonded from the factory you must use STRW welders in that area. i would assume in the future they will remove this recommendation when there is more crash testing and there are more STRW welders in shops.
i re read this and it sounds like i am contradicting myself.
you CAN'T mig weld UHSS PARTS ON with a mig welder PERIOD. there are no exceptions to this.
you CAN mig weld outer sheetmetal TO THE UHSS PART along the mounting flanges, under the weatherstrip .like a 1/4 panel edge where it meets the inner structure in the door jamb.
it's not highly recommended but you can do it as a last resort. I-Car recommends using a STRW welder as your first choice. plug welding with silicon bronze is the second choice.
i would assume I-Car lets this happen is due to politics of smaller shops not wanting to purchase $30K welders that are only useful in limited areas
the way cars are being built with more and more technical parts with specialized technique in them the less likely the smaller shops will exist anymore.
