The Research On Design Of Cu-Al Welded Joints Based On Green Theory And Method

Due to the increase in price of copper，there has been a trend of employing aluminumpipe instead of copper pipe in refrigeration industry，because of its similar thermalconductivity at a reduced market price and lower specific density. The copper-aluminumpipe has been widely used in the refrigeration industry. The connection process of dissimilarmaterials such as aluminum and copper uses the brazing method to form a permanent joint.For this reason a large number of mechanical and electrical products of copper andaluminum parts brazed joints was abandoned，caused a serious waste of resources. Regardthis，remanufacturing of Cu-Al brazed composite on the basis of4R（Reduce，Reuse，Remanufacture，Recycle）is really urgent currently. However，the thermal separating methodand electrolytic separating method could only separates Cu/Al butt joints with Al-12Si fillersalloys，it cannot separates Cu/Al lap joints. For this reason it is intended to introduce thegreen welding，which will be integrated into the product’s entire life cycle of processgradually，From the design，development， manufacturing to maintenance，recycling，everystage. Green design is an important part in manufacturing electronic products.In this work，the3㎜，5㎜，7㎜and10㎜lab length of the Cu-Al brazed joints hadbeen researched. In this study introduced the green welding，which will improve the recycleability of the Cu-Al brazed joints from technological design source. And to Cu-Al brazedjoints life cycle of energy dissipation evaluated，thus for Cu-Al brazed joints design providethe reasonable and feasible energy analysis method and the application method.The macrostructure and leak tightness，and bonding strength of the interface of Cu-Albrazed joints were analyzed respectively. It is seen from the macrostructure pictures，When5㎜lab length(X) was designed bonding interface quality revealed the perfect. The Shearstrength test Shows that the shear strength increased at first with increasing lab length from3㎜to7㎜and then decreased as the lab length moved beyond7㎜.It showed that the shearstrength of the7㎜joints was the best under the same condition，the maximum shearstrength of the7㎜joints can reach75.64MPa. It is evident that in the interfacial leaktightness of joints test，the lap joints did not leak finally even after joints were subjected tothermal cycles，except the lap length of Cu-Al brazed joints is3mm.Therefore，lab lengthfrom5㎜to10㎜，this range of the joints lab length can settle for industrial requirement.Finally，the adapted lap length parameters within the scope of this study weredetermined according to a criterion of the recycle experiment. It is concluded from thetheoretical and experimental results that the lab length for5㎜of Cu-Al brazed joints withAl-12Si fillers alloys complies with the green welding design concept. Cu-Al brazed jointslife cycle of energy dissipation evaluated indicate that the high welding method andreasonable lap length is very important to improve the utilization ratio of material.