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In this study, the welding joint of vanandium alloy (V5Cr5Ti) and HR-2 steel was investigated based on the microstructural analysis and mechanical property by optical microscope (OM),X-ray diffraction(XRD),transmission electron microscope(TEM).Results show that using both focus point migration and inclided groove, a defect-free joint can be achieved when the fusion ratio of vanandium alloy was controlled to be less than 15%. The tensile strength is approximately 400 MPa, and the fracture surface exhibits typical mixed fracture mode. The formation of phases in the weld boundaries is affected by the fusion ratio of vanadium alloy and the directional diffusion of vanandium atoms to the low temperature zone during initial stage of solidification. When the degree of vanandium enrichment is low, Fe-Cr substitutional solid solution with bcc structure is formed. When the V/Fe ratio was higher than 4 ot 2, intermetallics such as Fe_0.1Ti_0.18V_0.72, V₂Cr₂Fe appear. The occurrence of hot cracking and cold cracking is due to the formation of vanadium-rich intermetallics, thermal stress (approximately 400 MPa) during welding cycle and residual stress (approximately 300 MPa).