材料期刊网

为实现铜／钢异种材料的优质连接，研究了铜／钢焊接接头的显微组织特点及其组成，试验采用LHM－200等离子弧焊系统对紫铜（ T2）与不锈钢（304）异种材料进行焊接，然后通过光学金相显微镜及能谱分析仪，观察分析接头显微组织，研究其接头组织结构及组成．研究结果表明：铜／钢异种材料的等离子弧焊焊缝在铜一侧为平直的，而在钢一侧则为半χ型，在铜侧界面形成漩涡状；在焊接接头的形成过程中铜元素的迁移和扩散主要依靠钢液的流动所带动；焊接接头显微组织主要为奥氏体组织，弥散分布着块状和粒状的铜和钢的固溶体组织，和黑色鱼骨状的α相铁素体组织；焊缝区组织主要是以α、γ富铁相和ε富铜相固溶体组织的形式存在．通过实现发现最佳的焊接参数为：保护气流量与离子气流量分别为0．25 L／min和0．75 L／min，焊接电流为65 A，焊接速度为4 mm／s，焊接后的接头抗拉强度能达到174 MPa．

In order to study the microstructure of copper/steel welding joint and realized the high quality connection of copper/steel dissimilar materials. The research on plasma arc welding of dissimilar materials between T2 copper and 304 stainless steel was carried out with LHM-200 plasma arc system. After that the formation and microstructure of the weld joint were analyzed by Optical microscope and Energy Dispersive Spectrometer. The results indicated that the copper side of the plasma arc welding of copper?steel dissimilar materials is straight seam, and the steel side was half?χ?shape, the interface of the copper side with weld seam is spiral shape, during the joint formation process, the migration and diffusion of Cu elements mainly driven by the flow of liquid steel; the microstructure of the joints included austenitic, diffuse distribution of block?shape and granular?shape solid solution of copper and steel, and black fishbone?shape α?phase ferrite microstructure, and the weld area organizations mainly is iron?rich α?phase, iron?rich γ?phase and copper?rich ε?phase solid solution; The optical welding parameters were 65 A of weld current, 4 mm/s of welding speed, 0.25 L/min and 0.75 L/min of gas flow and plasma flow respectively, and the tensile strength of welded joint reached 174 MPa with these parameters.