High-Speed X-Ray Transmission and Numerical Study of Melt Flows inside the Molten Pool during Laser Welding of Aluminum Alloy

Table 3

Temperature profiles and flow patterns of molten pools corresponding to temperature gradient of point A and point B and flow velocities of point B at different preheating temperatures during laser welding of aluminum alloy at 50 mm/s welding speed and 4 kW laser power.

Preheating temperature	Top view	Longitudinal section view	Temperature gradient of point A and point B	Flow velocity of point B
273 K (ambient temperature)			252 K/mm	32 mm/s
373 K			279 K/mm	65 mm/s
533 K			298 K/mm	70 mm/s