Microstructure, properties and fracture failure mechanism of MAG welded joints of four types of stainless steels

•Four types of stainless steel with different chemical composition were MAG butt welded.•Solidification modes, microstructure and mechanical properties of the four welded joints were studied.•Fracture mechanisms of the four welded joints were analyzed from the perspective of crystallography.•FQZ generated from FA solidification mode is the main reason for the 304 and 316L welded joints fracturing at HAZ.•Improved understanding of the fracture mechanisms of the four welded joints provides technical guidance for application of different stainless steels.