Research On High-hardness And High-conductivity Copper Alloy Used On Twin-roll Continuous Casting Process Of Thin Strip

CuNiSiCrZr alloys used on cooling roller for continuous casting of thin strip were prepared by medial frequency smelting, iron mould casting, hot forging, solid solution, cold forging as well as aging. Through orthogonal experiment, hardness measurement, electrical test, XRD, SEM analysis et al, the mechanical, electric and microstructure of above alloys at different heat treatment were studied, analyzed and explained in theory. The results are shown as follows:(1) High-strength and high-conductivity copper alloys researched in experiment have not only good mechanic performance but also good electricity performance. The hardness and the conductivity of alloys reaches HBW180 and 45%IACS respectively. Moreover the anti-softening temperature of alloys can reach 600 °C. The copper alloy performance had already achieved an advanced level both in home and abroad.(2) The element atom number ratio of Ni to Si imposes profound influence on the hardness and the conductivity of alloys. When the ratio is between 4 an 5, it has little influence on conductivity performance of alloys and has good strengthening effect on alloys.(3) Among several factors exerted on performance of alloys, the aging temperature and the aging time has most profound influence on performance of alloys, and the optimum aging parameters is 470 °C and 2h.(4) The influence imposed by the solution temperature and solution time on the mechanics and electricity performance is also profound. The results show that when solution temperature and time is 940 °C and 2h respectively, solution element atoms dissolve into Cu crystal lattice completely. Because of the short solution time, the grains growth phenomenon is not obvious and the finer grains exist still.(5) The bigger the cold forging ratio is, the higher the maximum hardness of alloys can be obtained within a shorter time. Meanwhile the conductivity is higher sothe optimum cold forging ratio of 75% is chosen.(6) The results show that, the softening temperature is approximately 600 °C. Below this temperature, the hardness of alloy varies with annealing temperature smoothly, and copper alloys don't result in obvious recrystallization and have better high-temperature hardness.