Fig. 1. Schematic of micro-hardness measuring of laser welded joints

Fig. 2. Schematic of tensile specimen of laser welded joints

Fig. 3. Macro morphologies of laser welded joints and microstructures at different locations of weld. (a) Macro morphology of laser welded joints; (b) microstructure at the top of weld; (c) columnar dendritic structure in the middle of weld; (d) microstructure at the bottom of weld; (e) local magnification of Fig. 3 (b); (f) local magnification of Fig. 3 (c); (g) local magnification of Fig. 3 (d)

Fig. 4. Stress-strain curve of tensile specimen

Fig. 5. Fracture morphologies of tensile specimen. (a) Low magnification; (b) high magnification

Fig. 6. Micro-hardness distribution of welded joints

Table 1. Chemical compositions of 316LN austenitic stainless steels (mass fraction, %)

Table 2. Effect of welding speed on surface appearances and cross sections of welds

Table 3. Effect of defocus on surface appearances and cross sections of welds

Table 4. Effects of welding speed and laser power on surface appearances and cross sections of welds