Blue laser welding of laminated electrical steels: Dynamic process, weld bead characteristics, mechanical and magnetic properties

Abstract

Laminated electrical steels are the key material structure of the stator and rotator of a motor, where high-quality welding is crucial for improving the performance of the electric machine. However, it is challenging to achieve a desired balance among the magnetic properties, mechanical properties, and welding efficiency for the laminated electrical steels at present. This work first adopted a 450 nm flat-top blue laser with a maximum power of 2000 W, which has a higher primary absorption rate to Fe compared to that of the conventionally used 980–1080 nm infrared laser, to join the laminated electrical steels. The dynamic process, weld bead characteristics, mechanical properties, and magnetic properties of the blue laser welding of laminated electrical steels were investigated. The results showed that a flat-top and large-spot blue laser could make the molten pool have a self-stabilizing ability to keep the continuity when encountering the gap and unsmooth surface. Moreover, a further improved self-stabilizing ability was observed for a small welding speed. The largest depth and width of the blue laser weld bead in this work were 2.30 and 0.57 mm, respectively, with a shear strength of up to 1700 N, which were achieved at the laser power of 1500 W and welding speed of 10 mm/s. In addition, the work also validated that the blue laser could significantly reduce the splashing in welding of electrical steel laminations and improve the welding efficiency, which provides a promising solution for high-performance electrical machine manufacturing.