钢铜异种金属焊接接头组织与性能

Microstructure and properties of steel-copper dissimilar metal welded joint

采用镍基焊材钨极氩弧焊制备T2/Q345钢铜异种金属焊接接头,采用X射线衍射仪、金相显微镜、扫描电镜、显微硬度计、万能材料试验机进行接头组织和性能分析。焊接接头中焊缝金属与两侧母材具有良好的物理、化学相容性。焊缝金属为具有柱状树枝晶和等轴晶的面心立方γ相。由于氩弧焊热源集中及铜合金的导热能力较高,热影响区两侧粗晶区范围较小。成分分析结果显示,在靠近熔合线的铜合金母材区域发生了Ni、Cr元素扩散现象。拉伸试验结果表明,焊接接头断裂在铜合金母材位置,该处显微硬度最低,接头表现出良好的力学性能。

T2/Q345 steel-copper dissimilar metal welded joint is fabricated by argon tungsten arc welding with nickel-based welding material.X-ray diffractometer,metallographic microscopy,scanning electron microscopy,microhardness tester and universal materials tester are used to analyze the microstructure and properties of the welded joints.Weld metal and base metals on the both side in welded jonit have excellent physical and chemical compatibility.Weld metal consists of face-centered cubic γ phase with the apperance of columnar dendrite and equiaxial dendrite.Due to the heat source concentration of argon arc welding and high heat conductivity of the copper alloy,the range of the coarse grained region on both sides of the heat affected zone is very limited.Chemical composition analysis result shows that diffusion of Ni and Cr occurs in the T2 heat affected zone.Tensile testing result shows that the welded jonit fractures in the position of the copper alloy where the microhardness is minimum and the welded joint shows good mechanical properties.