Effect of Laser Welding on Performance of the B1500HS/340LA High-Strength Steel

In this study, high-strength steels B1500HS and B340LA were used as base materials, and laser welding experiments were conducted within a parameter range of welding power from 1500 W to 3000 W and welding speed from 15 mm/s to 35 mm/s. Microstructural analysis, microhardness testing, and uniaxial tensile tests were performed to systematically investigate the effects of different welding parameters on the weld microstructure and macroscopic mechanical properties, leading to the identification of an optimal welding parameter range that avoids defect-prone regions. The bending formability of tailor-welded blanks (TWBs) was evaluated using hat-shaped bending tests, with finite element simulations employed to analyze the effects of welding parameters on stress distribution and material hardening behavior. Based on the identified high-quality welding parameters, a suitable welding parameter range for reverse bending conditions was determined, effectively improving the bending formability of TWBs and providing theoretical guidance and experimental support for their engineering applications.