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

Abstract

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.