Working With Boron-Alloyed Steel – Attachment GMA (MIG) Welding

B-pillar and rocker panel reinforcements are often replaced at factory seams.
B-pillar and rocker panel reinforcements are often replaced at factory seams.

When GMA (MIG) welding ultra-high-strength steel (UHSS), like boron-alloyed steel, there are a few additional things to consider. Most UHSS parts are typically replaced using squeeze-type resistance spot welds (STRSW) at a factory seam and GMA (MIG) plug welds used to attach the part where a spot welder cannot reach.

Some vehicle makers like Honda and Acura do not allow GMA (MIG) welding on 1,500 MPa steel. Instead, they require MIG brazing in the areas that cannot be reached with a spot welder. 

When replacing UHSS parts, continuous seam welds should not be used unless it is identified in the vehicle maker repair procedure. If the vehicle maker repair procedure includes a continuous weld on UHSS, the skip, or stitch, technique should be used to help control the heat-affect zone (HAZ).

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