Laser welding for hot-stamped tailor-welded blanks with high-strength steel/high-energy absorption steel

In this research, the laser weldability for tailor-welded blanks (TWBs) made of dissimilar hot-stamping steels was examined. Usibor and Ductibor from ArcelorMittal were combined, since they are steels that possess a high-strength and high-energy absorption, respectively. Additionally, combination of Usibor and SPRC440 was investigated for comparison. After laser butt welding, the specimens were heat-treated at high temperatures, and the subsequent quenching conditions were similar to those in the hot-stamping process. The mechanical and metallurgical characteristics of the welds were then analyzed. The TWBs with Usibor and Ductibor exhibited a high degree of elongation after hot-stamping but those with Usibor and SPRC440 showed a relatively low elongation. The AlSi coating on the base metal was included in the fusion zone, and it led to ferrite formation. However, in the static and high-speed tensile tests, the AlSi coating did not affect the tensile strength of the TWBs, and all tensile specimens were fractured at the base metal of Ductibor. (C) 2014 Laser Institute of America.