Fig. 1. Schematic diagram of the welding process

Fig. 2. Schematic diagram of bevel size

Fig. 3. Schematic of the tensile specimen. (a) Selection location of tensile sample; (b) size of tensile sample

Fig. 4. Cross-section morphology of welds with different combinations. (a) Sample A1; (b) sample A2; (c) sample A3; (d) sample A4

Fig. 5. Microstructure of 316L austenitic stainless steel

Fig. 6. Filling weld structure. (a) (d) HAZ of A1 and A3; (b) (e) weld center of A1 and A3; (c) (f) zones of A and B

Fig. 7. Underlying weld structure. (a) (d) HAZ of A1 and A2; (b) (e) weld center of A1 and A2; (c) (f) zones of C and D

Fig. 8. Schematic diagram of fracture locations of tensile test specimens

Fig. 9. Stress-strain curves at different positions of each sample joint. (a) Filling weld; (b) underlying weld

Fig. 10. Fracture morphology of tensile samples. (a) (b) Upper layer fracture of A1 and its micro area; (c) (d) upper layer fracture of A3 and its micro area; (e) (f) lower layer fracture of A1 and its micro area; (g) (h) lower layer fracture of A2 and its micro area

Fig. 11. Microhardness of different parts of the weld joint. (a) Filling layer; (b) underlying layer