Effects of interfaces on heat transfer in laser welding of electrical steel laminations

Laser welding is one of the most potential methods for joining of electrical steel laminations, which is commonly used in motor, transformer and compressor. Because of the existence of multiple interfaces in the welding path, the heat transfer in laser welding of the electrical steel laminations is significantly different from that in the normal welding. In this study, a finite element model (FEM) considering the effects of interfaces has been developed in ANSYS to analyze the heat transfer in laser welding of electrical steel laminations. The contact elements with birth and death options were used to describe both the existed and the vanished statuses of the interfaces during welding. The simulation results showed that the temperature distribution in the zone beside the interfaces was discontinuous at first and then changed to be continuous after the interface vanished. The highest temperature fluctuated periodically during the welding process because of the effects of multiple interfaces. The joint area decreased with the increase of sheet thickness but was robust with respect to the normal pressure applied on the sheets and the contact statuses of the interfaces to some extent. The estimated joint areas at various welding velocities were validated by experimental results. This work provides a better understanding of the heat transfer in laser welding of the electrical steel laminations.