Fig. 1. Schematics of partial penetration laser welding experiment. (a) Physical map of welding fixture; (b) schematic of partial penetration laser welding; (c) schematic of pre-deformation experiment

Fig. 2. Macro appearances of weld obtained by partial penetration laser lap welding and micro bulging distortion. (a) Weld side; (b) weldless side

Fig. 3. Cross-sectional morphology of partial penetration laser welding joint obtained at different laser powers. (a) 1.9 kW; (b) 2.0 kW; (c) 2.1 kW; (d) 2.2 kW; (e) 2.3 kW; (f) 2.4 kW; (g) 2.5 kW; (h) 2.6 kW

Fig. 4. Penetration depth of SUS304 steel plate at different laser powers

Fig. 5. Three-dimensional model of micro bulging distortion at different powers( width of measurement area is 2 mm). (a) Mirror region; (b) 2.4 kW, and width of measurement area is 8 mm; (c) 1.9 kW; (d) 2.0 kW; (e) 2.1 kW; (f) 2.2 kW; (g) 2.3 kW; (h) 2.4 kW; (i) 2.5 kW; (j) 2.6 kW

Fig. 6. Two-dimensional profile of micro bulging distortion of the lower steel plate at weldless side. (a) DC01-SUS304 welding joint; (b) DC01-Q235 welding joint

Fig. 7. Maximum bulging distortion height of SUS304 steel back at different pre-deformation values

Fig. 8. EBSD-IPF images of micro bulging distortion area. (a) Morphology of region about 1.5 mm away from bulging distortion center; (b) morphology of region about 1 mm away from bulging distortion center

Fig. 9. Schematic of micro bulging distortion plastic compression