Product Code: PIC2008_604

Studies on the Laser Spot Welding of Magnet/Steel Dissimilar Materials
Authors:
Baohua Chang, Tsinghua University; Beijing Peoples Republic of China
Shaojun Bai, Tsinghua University; Beijing Peoples Republic of China
Xiaogong Li, University of Waterloo; Ontario Canada
Yuquan Ding, University of Waterloo; Ontario Canada
Hua Zhang, Tsinghua University; Beijing Peoples Republic of China
Dong Du, Tsinghua University; Beijing Peoples Republic of China
Yunhong Zhou, University of Waterloo; Ontario Canada
Presented at PICALO 2008

Laser spot welding of high performance sintered NdFeB magnets of grade N48 and SPCC cold rolled steel were carried out. How welding parameters of pulsed Nd:YAG laser spot welding affect the weld quality was investigated, such as laser pulse power, pulse duration, pulse frequency, pulse number and defocusing distance. The weld quality is evaluated by diameter and penetration of weld spot, in addition to the porosity and crater area of the joint. The experimental results indicate that welding procedures with wider pulse duration, appropriate defocusing distance, and Ar shielding atmosphere are advantageous to get better joint. The laser spot welded joints were tested to investigate the microstructure, composition and shear strength in comparison with the base metal. The test results show that the laser welding method is advisable to join NdFeB/steel dissimilar materials. However, laser spot welding of NdFeB has some problems, such as porosity, crack and crater. The porosity, crack and crater can be reduced by using appropriate parameters. This paper not only offers some useful experimental results for the micro laser welding of magnet material NdFeB, but also provides some necessary data to numerical simulation analysis of the micro laser spot welding process using finite element method.