Fig. 1. Flow chart of model calculation

Fig. 2. Location of liquid droplet filling

Fig. 3. Keyhole morphology of liquid droplet filling position at 0.5 mm

Fig. 4. Keyhole morphology of liquid droplet filling position at 1.8 mm

Fig. 5. Keyhole depth change for liquid droplet filling positions at 0.5 mm and 1.8 mm

Fig. 6. Molten pool flow field for liquid droplet at 0.5 mm filling position

Fig. 7. Molten pool flow field for liquid droplet at 1.8 mm filling position

Fig. 8. Flow velocity change at the H point inside the molten pool with liquid droplet filling position of 0.5 mm and 1.8 mm

Fig. 9. Schematic diagram for the keyhole stability influence by liquid droplet