50
2 Model of Quasi-Steady Weld Pool Dynamics and Numerical Simulation
2.6 Simulation of Weld Pool and Keyhole in Deep
Penetration Laser Welding
2.6.1 Numerical Simulation of Weld Pool Shape in Deep
Penetration Laser Welding
Figure 2.20 is the calculation result of laser weld pool of Titanium alloy in XOY
plane (z = 0.0025 m) when laser power is 3000 W, welding speeds is 0.03 m/s and
workpiece moves along the X-axis. For discussion purposes, the definitions of weld
pool length L and weld pool width B are shown in Fig. 2.20. The experiment shows
that the temperature gradient is larger in the front of the laser keyhole than in the
back of the laser keyhole, and the direction of heat flow is obvious. The simulation
results show that the principal axis direction of the weld pool is closely related to the
moving direction of the workpiece. The shape of isotherm is similar to that in other
welding methods. It is asymmetrical longitudinally with the welding direction as the
long axis. The front of the weld pool is at the heating stage. The temperature gradient
is larger and the heat action is stronger. The convective heat transfer of molten metal
and the heat conduction of solid metal at the front of the weld pool play a role at the
same time. After carefully observing the position of the laser keyhole center and the
position of the widest weld pool, it is found that the position of the widest weld pool
Fig. 2.20 The shape and size of weld pool on upper surface of the workpiece in XOY plane during
deep penetration laser welding
2 Model of Quasi-Steady Weld Pool Dynamics and Numerical Simulation
2.6 Simulation of Weld Pool and Keyhole in Deep
Penetration Laser Welding
2.6.1 Numerical Simulation of Weld Pool Shape in Deep
Penetration Laser Welding
Figure 2.20 is the calculation result of laser weld pool of Titanium alloy in XOY
plane (z = 0.0025 m) when laser power is 3000 W, welding speeds is 0.03 m/s and
workpiece moves along the X-axis. For discussion purposes, the definitions of weld
pool length L and weld pool width B are shown in Fig. 2.20. The experiment shows
that the temperature gradient is larger in the front of the laser keyhole than in the
back of the laser keyhole, and the direction of heat flow is obvious. The simulation
results show that the principal axis direction of the weld pool is closely related to the
moving direction of the workpiece. The shape of isotherm is similar to that in other
welding methods. It is asymmetrical longitudinally with the welding direction as the
long axis. The front of the weld pool is at the heating stage. The temperature gradient
is larger and the heat action is stronger. The convective heat transfer of molten metal
and the heat conduction of solid metal at the front of the weld pool play a role at the
same time. After carefully observing the position of the laser keyhole center and the
position of the widest weld pool, it is found that the position of the widest weld pool
Fig. 2.20 The shape and size of weld pool on upper surface of the workpiece in XOY plane during
deep penetration laser welding