Electron beam braze-welding of vanadium alloy to stainless steel with electroplated Cu/Ag coatings

【摘要】 Cracks may easily occur in the fusion weld between vanadium alloys and stainless steel due to the brittle intermetallics and welding stress.The high vacuum electron beam braze-welding has been successfully used to join vanadium alloy(V-5Cr-5Ti) to stainless steel(HR-2) with electroplated Cu and Ag coating.To investigate the effects of electroplated coating on the weldability,the joint appearance,the microstructure and the mechanical properties of the joints have been thoroughly analyzed.The results show that the joint surface configuration was good and root reinforcement was full and smooth.A reaction zone(RZ) was gained on the interface between the VSCrSTi alloy and HR-2 stainless steel base metals.The width of reaction zone at the top of the joint was up to 0.65 mm,wider than that in the bottom of the joint(0.46 mm).The reaction zone consisted of considerably smaller dendritic structures with an average grain size of less than 10 μm.Element Ag and Cu almost enriched the interface between V-5Cr-5Ti alloy substrate and RZ,serving as a physical barrier which decreases or avoids the formation of intermetallics.The maximum tensile strength of vanadium alloy/stainless steel dissimilar alloy joint was more than 300 MPa.The joint was defects free.更多还原

【Abstract】 Cracks may easily occur in the fusion weld between vanadium alloys and stainless steel due to the brittle intermetallics and welding stress.The high vacuum electron beam braze-welding has been successfully used to join vanadium alloy(V-5Cr-5Ti) to stainless steel(HR-2) with electroplated Cu and Ag coating.To investigate the effects of electroplated coating on the weldability,the joint appearance,the microstructure and the mechanical properties of the joints have been thoroughly analyzed.The results show that the joint surface configuration was good and root reinforcement was full and smooth.A reaction zone(RZ) was gained on the interface between the VSCrSTi alloy and HR-2 stainless steel base metals.The width of reaction zone at the top of the joint was up to 0.65 mm,wider than that in the bottom of the joint(0.46 mm).The reaction zone consisted of considerably smaller dendritic structures with an average grain size of less than 10 μm.Element Ag and Cu almost enriched the interface between V-5Cr-5Ti alloy substrate and RZ,serving as a physical barrier which decreases or avoids the formation of intermetallics.The maximum tensile strength of vanadium alloy/stainless steel dissimilar alloy joint was more than 300 MPa.The joint was defects free.更多还原