Laser welding of ultra-high strength steels for automotive applications

Abstract

The work in this paper was concerned with the development of welding procedures for joining thin-sheet UHS steels, using fibre-delivered solid state lasers and establishing the strength and formability of the welds produced. Autogenous laser welding trials were conducted with three different fibre-delivered solid state lasers to achieve fully penetrating butt and lap welds in dual phase (DP), martensitic, transformation induced plasticity (TRIP), Usibor and boron steels of 0.8-1.5mm thickness and 600-1550N/mm2 tensile strength with similar and dissimilar material combinations. The hardening and softening behaviour in the fusion zone and the heat affected zone were determined. Influences of laser process parameters on welding speed, weld profile and joint performance were discussed.The work in this paper was concerned with the development of welding procedures for joining thin-sheet UHS steels, using fibre-delivered solid state lasers and establishing the strength and formability of the welds produced. Autogenous laser welding trials were conducted with three different fibre-delivered solid state lasers to achieve fully penetrating butt and lap welds in dual phase (DP), martensitic, transformation induced plasticity (TRIP), Usibor and boron steels of 0.8-1.5mm thickness and 600-1550N/mm2 tensile strength with similar and dissimilar material combinations. The hardening and softening behaviour in the fusion zone and the heat affected zone were determined. Influences of laser process parameters on welding speed, weld profile and joint performance were discussed.