Fig. 1. Schematic of oscillating laser welding

Fig. 2. Macrographs of laser-welded joint.(a) External;

Fig. 3. Cross-sectional morphology of laser welded joint

Fig. 4. X-ray radiograph of laser welded joint

Fig. 5. Microstructures of test materials. (a) Base material T91; (b) base material TP347H

Fig. 6. Interface conditions after single-mode laser welding. (a) T91 side interface; (b) TP347H side interface

Fig. 7. Interface structure on T91 side after multimode laser welding

Fig. 8. Microstructures of T91 base metal and heat-affected zone. （a） Cross section of joint； （b） enlarged image at B position in Fig.8（a）； （c） enlarged image at C position in Fig.8（a）； （d） enlarged image at D position in Fig.8（a）

Fig. 9. Microstructures of HAZ on TP347H side. (a) Microstructure; (b) local magnification

Fig. 10. Microstructures of weld seam. (a) Upper part of weld seam; (b) middle part of weld seam; (c) lower part of weld seam

Fig. 11. Tensile fracture specimen of welded joint

Fig. 12. Cross-sectional morphologies of tensile fracture specimen of dissimilar steel welded joint. (a) Morphology; (b) local magnification

Fig. 13. SEM images of fracture of tensile fracture specimen of welded joint. (a) Center; (b) exterior

Fig. 14. Bend sample of welded joint. (a) Side view; (b) front view

Fig. 15. Microhardness distribution of welded joint