Abstract:
In this work, the Nb/304 SS joint was welded by laser welding. The joint fractured immediately due to continuously distributed Fe
2Nb intermetallic compounds when the laser was directed to the Nb/steel interface. In order to solve the problem, the laser beam-offset welding procedure was proposed. The amount of melted niobium was reduced by the laser offset effect. Finally, the formation of Fe
2Nb intermetallic compounds was controlled. The results showed that laser beam-offset welding was an ideal way to control the joint crack which occurred in laser centered welding condition. The joint microstructure was mainly consisted of
γ austenite phase and a certain amount of Fe
2Nb intermetallic compounds with little
δ ferrite phase. The tensile strength of the joint was 221 MPa, the fracture occurred in the Fe2Nb intermetallic compounds layer. The highest microhardness existed in Fe
2Nb intermetallic compounds layer with a value of 1 143 HV.