The welding of steel grades for the direct hot stamping like Usibor® and Ductibor® require a dedicated welding process. This process includes a previous partial ablation of the weld edges, in order to remove the AlSi coating before the welding operation.

Components tests like the three point bending tests with the load applied on the weld region have been performed in order to validate the ArcelorMittal process.
We observed that butt laser welding without ablation or with inappropriate ablation leads to mix of coating material (Aluminium) into the molten steel and may drive eventually to fracture of the assembly.

New VDA accelerated corrosion test
Duration of the test for corrosion: 6 cycles (one cycle = one week).

Corrosion behavior of the weld is very good, being similar to the base material.
ArcelorMittal process: no red rust for normal ablation width, almost none for abnormally large width.