Recent Trends to Improve Laser Weldability of Al-Si coated Hot-stamped Boron Steel

Abstract

The current demand for vehicles with high fuel efficiency, which has improved their safety, as well as enhanced crash worthiness qualities is being met by the use of high-strength components fabricated via the hot stamping process. Most of the Al-Si coated layer is applied to prevent oxidation and decarburization caused by this process. During laser welding, the layer is diluted in the fusion zone and segregation, and ferrite is formed in some areas, causing deterioration of mechanical properties. In this paper, we provide a comprehensive review for the weldability improvement of Al-Si-coated boron steel from various aspects. Three main solutions have been applied to form full austenitization in the fusion zone; removing the Al-Si coated layer, inducing strong austenite stabilizers, and introducing new laser welding process such as arc pre-treatment, dual-beam laser welding, and laser oscillation welding.