Materials behavior in laser welding of hardmetals to steel

Tool manufacturing industry faces the problem of permanently joining hardmetals to steel holders with high shear strength. The mostly used welding process still is brazing. However, brazed joints have poor lifetimes, mostly when high temperatures are achieved and often break in operation. In a previous study about the ability of CO2 and Nd:YAG lasers to weld hardmetals to steels, it was found that Nd:YAG lasers, working in continuous wave mode, could be used especially for welding hardmetals with Co content around 12%. This article discusses the materials behavior under laser radiation and analyzes the microstructural features observed.