关键词: 钒合金;不锈钢;电子束焊接;熔-钎;阻隔

Abstract: Electron beam welding(EBW), electron beam welding-brazing(EBWB) and electron beam isolation welding(EBIW) for the dissimilar combination of vanadium alloy and stainless steel will be studied in this project. The present results show that the brittle intermetallic compound formed in the welding process is the key factor to influence the joint properties. The penetrated crack is formed in EBW process directly leading to the joint unsuccessful. In EBWB process, the joints have the characters of welding and brazing and the metallurgically bonded joint is achieved without melting the vanadium alloy sheet. The liquid-to-solid interalloying of dissimilar materials well controlling, a reaction zone is gained on the interface. 20 m-thick interaction diffusion layer is formed in the interface of V base metal and reaction zone and no interfacial intermetallic σ-phases detected in the joint. The maximum tensile strength of vanadium alloy/stainless-steel of EBWB joint is up to 200 MPa. Ag as filler material exhibited good isolation layer which helps minimizing the formation of V/Fe intermetalics, increasing the weld quality. The tensile strength of vanadium alloy/stainless-steel of EBWI joint is more than 400 MPa. The welded seams are good shape as well as the back of the joints and there is no crack and detected porosity in the joints of EBWB and EBWI through X-ray inspection.

Key words: vanadium alloy;stainless steel;electron beam welding;welding-brazing;isolation