EFFECT OF LASER WELDING ON SAFETY CHARACTERISTICS OF HIGH STRENGTH STEELS SHEETS

In the automotive industry considerable attention is paid to innovations oriented especially to meeting safety and environmental requirements. Concepts of vehicle safety focus on resistance of deformation zone components to impact and resistance to intrusion of undesirable fragments into the passengers´ space. In terms of these aspects the samples of the base materials from micro-alloyed steels HSLA - H220PD, DP 600 and TRIP - RAK 40/70 and also welded by solid-state fibre laser YLS-5000 were analysed. Multi-phase structure materials TRIP - RAK 40/70 and DP 600 showed considerably higher values of absorption capacity, strength, and stiffness than in case of single-phase structure material HSLA - H220PD. The greatest values of absorption capacity, strength, and stiffness were recorded in material TRIP - RAK 40/70 with ferritic matrix and a certain fraction of residual austenite, bainite, and martensite. Absorption capacity, strength, and stiffness have strong correlation with material constant K and strain hardening exponent.