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6 Behaviors of Keyhole and Weld Pool Under the Effect …
(3) Under the pressures of metallic vapors, the diameter of the keyhole on the cross
section first increases with the expansion of the keyhole, and then decreases
with the refilling of molten melt after reaching the maximum; Moreover, after
completing the refilling stage of the molten melt, the diameter increases again
with the expansion of the keyhole. The expansion of the keyhole in the radial
direction can make the wall of the keyhole closer to the solid–liquid interface.
In this way, the energy carried by the beam directly acts at the position closer
to the solid–liquid interface and is more effectively and directly applied in
the workpiece far away from the axis of the keyhole in the radial direction.
Therefore, this facilitates the formation of a larger weld width.
6 Behaviors of Keyhole and Weld Pool Under the Effect …
(3) Under the pressures of metallic vapors, the diameter of the keyhole on the cross
section first increases with the expansion of the keyhole, and then decreases
with the refilling of molten melt after reaching the maximum; Moreover, after
completing the refilling stage of the molten melt, the diameter increases again
with the expansion of the keyhole. The expansion of the keyhole in the radial
direction can make the wall of the keyhole closer to the solid–liquid interface.
In this way, the energy carried by the beam directly acts at the position closer
to the solid–liquid interface and is more effectively and directly applied in
the workpiece far away from the axis of the keyhole in the radial direction.
Therefore, this facilitates the formation of a larger weld width.