用氮化硅陶瓷刀具车削与铣削堆(喷)焊镍基合金

堆(喷)焊镍基合金具有较高的硬度和高温强度,且喷焊表面高低不平,切削加工十分困难。氮化硅陶瓷具有较高的强度、断裂韧性和高温硬度,是切削堆(喷)焊镍基合金最合适的刀具材料。国产氮化硅陶瓷刀片的车削试验表明,选择合适的刀具几何尺寸和切削用量,其切削速度可比普通硬质合金刀具提高1～2倍,刀具耐用度可提高45倍,与进口陶瓷刀具的性能十分接近。铣削试验表明,通过合理选择刀具前角和切削速度,采用不对称铣削方法,可以很好地解决刀具易崩刃的技术关键。工厂实际铣削阀板表明,采用氮化硅陶瓷刀片铣削与原来应用金刚石砂轮磨削相比,加工效率可提高2倍,经济效益非常显著。

Machining build-up(spray) welding nickel-based alloy by silicon nitride ceramic cutting tool

Build up(spray) welding nickel based alloy is very hard to machine owing to its high hardness and high temperature strength and its rough surface. Silicon nitride ceramic is the optimum material for cutting build up welding nickel based alloy for its high strength and fracture toughness and high temperature hardness. Turning test of homemade silicon nitride ceramic cutting tips shows that, by selecting rational tool sizes and cutting parameters, the cutting speed of the silicon nitride ceramic cutter is 1～2 times higher than that of general carbide tipped cutter, and the working durability can be raised by 4 5 times. And the milling test shows that, by selecting proper cutter rake and cutting speed, and by using the non symmetric milling method, the technical barrier of break of the silicon nitride ceramic tool can be overcome. Milling practice shows that, in comparison with grinding by diamond abrasion wheel, the machining efficiency of the silicon nitride ceramic tipped tool is improved twice, and remarkable financial profits can be obtained.