Fig. 1. Schemes of welding process and preset defocusing distance

Fig. 2. Diagrams of making process and dimension of specimen

Fig. 3. Weld appearances and cross-sections under different defocusing distances. (a) -4.5 mm; (b) -5.0 mm; (c) -5.5 mm; (d) -6.0 mm

Fig. 4. Microstructures of welded joint. (a) Overview; (b) partial enlarged drawing

Fig. 5. Microstructures of heat affected zone of sample under different defocusing distances. (a) -4.5 mm; (b) -5.0 mm; (c) -5.5 mm; (d) -6.0 mm

Fig. 6. Tensile strength of welded joint in 1Cr17Ni2 steel plate under different defocusing distances. (a) Stress-displacement curve; (b) tensile specimen

Fig. 7. Hardness distribution curves of welding joint of 1Cr17Ni2 stainless steel plate under different defocusing distances. (a) Distribution of positions of hardness test points; (b) hardness distribution curves