Improvement Of Cu-Al Pipe Automatic Welding Machine And Study Of Welding Test

Because of the rising of raw material prices of Cu, "Al instead of Cu "has become the development trend of the refrigeration industry. However, due to the low melting point of Al, the compact oxide film on the surface, so the welding performance is poor. To avoiding weaknesses, in the actual production, use Cu-Al transition, and joint other lines with Cu pipe, thus, the substitution is not complete, so weld a Cu pipe to each end of the Al pipe as a transitional in the cooling pipe. Cu-Al pipe is mainly applied to the refrigerator in the condenser and additional devices; therefore, the quality of the welded joints of the Cu-Al pipe is very important.To further improving the quality of welded joints of Cu-Al pipe, save resource and energy, improve the original automatic welding machine of Cu-Al pipe. Former welder in the welding processes is affected by voltage fluctuations and the larger coil temperature, grid voltage fluctuations affect the welding current, in the resistance welding, welding current directly affects the size of the welding heat, and the welding heat directly affects the quality of copper and aluminum fittings. Using voltage and temperature compensation control system so that the welding quality of Cu-Al pipes independent from voltage fluctuations and the coil temperature. In the actual welding process, when the input voltage change to the interval, the control system will use the appropriate interval on theθ-U relationship cubic spline interpolation to calculate the corresponding value ofθ, connected to the welding circuit to pass before the thrusters trigger plate, ensure the stability of welding current and then ensure the welding quality independent of voltage fluctuations. In the voltage fluctuations range allowed, use the improved Cu-Al pipe automatic welding machine for welding test. After the Cu-Al pipe are welded, microstructure and energy spectrum, tensile properties, tightness, pressure resistance, corrosion resistance are test.The results show that, in the welding joint of Cu-Al pipe copper atoms exchange with the aluminum atoms and form a Cu-Al fusion zone, and then achieve a permanent connection. The performances meet the requirements. Sum, Cu-Al pipe welder automatically achieve the desired results to improve basic,Coil power voltage fluctuations and temperature changes can not affect the quality of welded joints of Cu-Al pipe.The welding quality of Cu-Al pipe meet the requirements.