On Welding Method And Separating Technical Of Discarded Cu-Al Welded Joints

Cu-Al welded joints have been widely used in the refrigeration industry and electronic packaging industry . The paper had down some research on the remanufacturing of Cu-Al welded joints on the basis of remanufacturing philosophy. At the very start , the application of Cu-Al welded joints in air conditioning and refrigeration pipeline systems,in CPU radiators that used in desktop computers and notebook computers had been described.At the same time,the welded structures,welding methods and welding consumables in these applications had been also recommended in detail.In order to analysis the Join Methods of a few typical kinds of Cu-Al joints used in manufacturing,researches on chemical composition and microstructure of Cu-Al welded joints had been carried out.EPMA-1600 is used to analysis the chemical composition and the distribution of the composition ;microstructures of these joints have been investigated by EPMA-1600 and Optical Microscope.The results showed that Low-temperature soldering is widely applied in electronic packaging industry,Sn-Pb, Sn-Bi and Sn-Zn eutectic alloys are used in soldering process as the fillers.Cold pressure welding and Brazing are the main join methods that used in refrigeration industry, Al-Zn-Ag alloy and Al-Si-Cu alloy are used in brazing process as the fillers.Besides that Cu-Al Cold pressure welded joints are widely used in refrigeration industry for their high strength and good leak tightness.Remanufacturing based on 4R(Reduce, Reuse, Remanufacture, Recycle)was introduced to the separation research of Recycling Cu-Al welded joints for there are no such researches on the topic at home and abroad.Thermal method and electrolytic method were applied to separating Cu/Al brazed joints.The results are as follows:(1)Thermal separating method is a Convenient,efficient and energy-saving method in separating Cu/Al soldered joints which used Sn-Bi,Sn-Pb and Sn-Zn eutectic alloys as the fillers during soldering process,and the process dose few harm to the properties and composition of copper and aluminum;As to those Cu/Al brazed joints that used Al-Si-Cu and Al-Zn-Ag alloys as the fillers,thermal separating method could lead to changes in chemical composition of copper and aluminum,but still it can Separate Cu/Al brazed joints;the results of separating Cu-Al cold pressure welded joints is not ideal for part of the molten aluminum adhered to copper.(2)As to Cu-Al brazed joints , Electrochemical corrosion and Chemical corrosion Occurred during the electrolytic separating process.Electrolytic separating method could only separates Cu/Al Butt joints,but it cannot separates Cu/Al lapped joints because so much aluminum was eroded during the process.All the aluminum were eroded into the electrolyte in the process of separating Cu-Al cold pressure welded joints by electrolytic method.so,Cu-Al cold pressure welded joints could not separated by electrolytic method.