METALLURGICAL ASPECTS OF WELDABILITY OF MULTIPHASE STEELS FOR AUTOMOTIVE INDUSTRY

This paper presents some of technical aspects of the twin-spot laser welding of multiphase steels for automotive industry. The dual beam was obtained using a special optical system that divides a laser beam. The investigation was carried out in two main areas of welds, which are fusion and heat affected zones. The results show that in case of analyzed steels the use of twin-spot laser welding leads to changes in martensite morphology compared to single spot laser welding in both zones. The defragmented morphology suggests that tempering-like processes occur during the welding. This phenomenon causes the decrease in weld hardness compared to single spot laser welding.