The Welding Process Research On Friction Surfacing Of Dissimilar Metal Materials

This paper focus on the friction surfacing process of 2A12 aluminum with Q235 low carbon steel, explores the welding parameters, preheat temperature on weld formation and joint strength, orthogonal experiment method was used to explore the optimum process, muti-layer welding process was also studied. The low carbon steel with T2 copper friction surfacing process was also studied in this paper.The optimum spindle speed, welding speed and welding pressure matching relatio nship were obtained in this research, the first layer weldable interval was:spindle spe ed 700～900r/min, welding speed 40～100mm/min, welding pressure 3～7MPa. The para meters would affect the consumables’ real contact surface, which resulted in the chang es of the width and thickness of surfacing layer.The results of orthogonal experiment showed that:when there’s no preheated, spi ndle speeds 900r/min, welding speed was 60mm/min, pressure was 3MPa, and Preheati ng temperature was 200℃, spindle speed was 700r/min, pressure was 5MPa, welding speed was 80mm/min was the optimum parameters; the surfacing layer formed well an d no macroscopic defects; it can acquire muti-layer which the first layer was complete and good strength when spindle speed was 1000r/min, welding speed was 100mm/mi n and welding pressure was 4MPa.The joint strength could be improved by preheating the substrate:the maximum shear strength was 85MPa when substrate without being preheated and increased to 130.3MPa when preheating temperature was 200℃, showed mix brittle-ductile fracture and ductile fracture respectively. The hardness increased near the interface, and the surfacing layer hardness increased with the distance from the interface.Under the thermal-mechanical action, the surfacing layer, S(Al2CuMg) and θ(CuAl2) were uniformly distributed in the α(Al) solid solution, The grains were greatly refined. In particular, the grains which located at the steel side of the interface were deformed at the direction of rotation. Fe and Al inter diffusion in the range 9μm of the interface. XRD showed that Al2Fe3、 Al6Fe、AlFe3 intermetallic formed.Based on the research before, steel-copper joint can get a good metallurgical bond, Fe and Cu inter diffusion in a narrow range, the steel and copper will produce a mixed area when heat input was too large.