Copper And Cobalt Chrome Silicon Electrode Alloy Microstructure And Performance

Cu-Co-Cr-Si electrode alloy used for electric resistance welding were prepared by Ingot Metallurgy. Using hardness measurement, tensile test at room temperature, electrical resistance test at room temperature, optical microscopy, XRD, SEM, and TEM, the mechanical and electric properties and the microstructure of the forged alloy after different heat treatment were studied, and were also analyzed and explained in theory. The results show that:The first, After solid solution treatment, the process harden of forged specimens disappeared. And at the same time, hardness and strength decreased obviously, the matrix softens with plasticity increasing. The structure of the alloy after solid solution consists of a -Cu and x phase, which is an as-cast equilibrium phase and will not be dissolved during the solid solution. The solution temperature plays a more important role on the properties than the time does. The best solution treatment is 980 ℃, 60min.The second, Cu-Co-Cr-Si alloy is a typical aging strengthing alloy, and the ageing heat treatment could improve the properties of the alloy further. The precipitation strengthening and the depletion of the alloy elements in the matrix caused by the precipitation of supersaturation solid solution will improve the hardness, strength and the conductibility of the alloy simultaneously. The best ageing treatment is 480 ℃ , 4h.The third, Thermomechanical treatment(solution- cold-drawing- aging) can increase alloy's strength greatly and hardly decrease the conductibility of the alloy. The alloy in aging after cold-drawing was influenced by the interaction of precipitation and recrystallization. The precipitates not only can strengthen the matrix but also can restrain recrystallization. The strengthening mechanisms of the alloy mainly include solution strengthening, strain-strengthening and aging strengthening.The fourth, the softening temperatures of the alloy treated by 980℃/lh solution-ice saline quench-480℃/4h ageing, 980℃/lh solution-ice saline quench-40%cold deformation-480℃/4h ageing and 980℃/lh solution- ice saline quench-60%cold deformation-480℃/4h ageing are 667℃ , 632℃ and 564℃ respectively.ABSTRACTFinally, the optimal treatment of the electrode alloy is 980/lh solution-ice saline quench-40 % cold deformation, it's mechanical and electrical performance can reach o b 634MPa, o 02 = 575MPa. 6 5==8.9%, o T= 43 .2%IACS ; if the service temperature permits, the treatment of 980 癈 /In solution- ice saline quench-60%cold deformation-480 /4h ageing can also be chosen, it's mechanical and electrical performance can reach o b=342MPa, a 0.2=216MPa. 8 5=27.8%, o =74.3%IACSc...