Laser spot welding of AISI 304L: metallurgical and mechanical properties

Abstract

The present study aims at investigating the effect of laser mean power on mechanical and metallurgical characterisation of AISI 304L austenitic stainless steel laser spot welds. Macro- and microstructural examinations, microhardness test and the quasi-static tensile shear test were performed. Peak load, energy absorption and failure mode were used to describe the mechanical behaviour of welds. It was found that changing laser transfer mode from conduction to keyhole mode occurs with increasing the laser mean power. Moreover, increasing the laser mean power increases the penetration depth and the area of the fusion zone, changing the failure mode from interfacial to pullout. It was found that heat affected zone softening and fusion zone size are key controlling factors for mechanical properties of laser spot welded AISI 304L.