湿式微喷砂处理对切削TC4的涂层刀具表面完整性及切削性能影响

Effects of Wet Micro-blasting on Surface Integrity and Cutting Performance of Coating Tools for TC4 Cutting

采用涂层刀具高速切削TC4(Ti6-Al4-V)时,其寿命短的问题较为突出。对涂层刀具进行表面后处理可大幅提高涂层刀具的表面完整性,是延长刀具寿命的有效途径。针对高速干切削钛合金的TiAlN涂层刀具,选用湿式微喷砂处理工艺进行表面后处理,分析微喷砂处理对涂层刀具表面微观形貌、表面粗糙度、表面显微硬度、表面残余应力的影响规律,并进行高速干切削试验,深入研究微喷砂处理对涂层刀具寿命及磨损机理的影响。结果表明:合适的微喷砂处理工艺(水料混合湿式微喷砂,喷砂压强为0.1~0.5 MPa,喷砂时间为0~10 s,喷砂颗粒为Al_(2)O_(3)或ZrO_(2)颗粒)可去除涂层初始表面大颗粒、凸起等缺陷,从而改善刀具的表面形貌,但过高的喷砂参数会在涂层刀面引入凹坑、微裂纹等,增大了其表面粗糙度值。喷砂颗粒、喷砂时间主要影响颗粒撞击涂层表面时对TiAlN涂层材料的去除量,改变涂层刀面的形貌、粗糙度与残余应力,喷砂压强主要影响颗粒的冲击力度,改变表面的硬度与残余压应力。与未处理刀具相比,处理后的涂层刀具的表面完整性提升显著,稳定磨损阶段持续时间延长,刀具寿命可提升50%,微喷砂表面处理可广泛应用于各种涂层刀具表面处理。

The problem of short service life of coated tools is prominent in high-speed cutting of TC4(Ti6-Al4-V).The surface integrity of coated tools can be improved by surface post-treatment which is an effective way to improve the service life of coated tool.Experiment in high-speed dry cutting of titanium alloy is conducted with TiAlN coated tool which is post treatment by wet micro-blasting to reveal the influence of micro-blasting on surface micro morphology,roughness,micro hardness and residual stress.High-speed dry cutting tests are carried out to study the influence of micro-blasting on coated tool life and wear mechanism.The result indicates that the appropriate blasting process(water and particles mixed,wet micro-blasting,blasting pressure is 0.1—0.5 MPa,blasting time is 0—10 s,particle is Al_(2)O_(3)or ZrO_(2))can remove large particles,bumps and other micro defects of the coating surface to improve the surface morphology.However,too high blasting parameters has a significantly reduce tool life in machining,especially in high-speed cutting.The blasting particles and time mainly affect the removal of coating materials,and change the surface morphology,roughness and residual stress.The blasting pressure mainly affects the impact of particles,and improve the surface hardness and residual compressive stress.Compared with untreated tool,the surface integrity of treated tool improves obviously,the duration of stable wear stage is prolonged and the tool life can be increased by 50%.