铍铜合金断续切削后刀面磨损机理研究

Flank Wear Mechanism in Intermittent Machining of Beryllium Copper Alloy

目的研究断续切削过程温度变化对刀具粘结现象、涂层剥落和刀具磨损的影响。方法搭建了仿铣削加工的断续车削实验平台,采用热电偶法测量了断续切削过程中刀具后刀面在不同速度下的切削温度,利用带有能谱仪(EDS)的扫描电镜(SEM)观察后刀面随速度变化的磨损形貌并分析后刀面磨损区域的元素组成,阐述了后刀面温度和刀具磨损之间的联系,研究了Ti AlN涂层硬质合金刀具断续切削铍铜合金C17200时的后刀面磨损机理。结果随着切削速度的增加,刀具温度在v=500 m/min出现峰值,温度越高,后刀面的涂层剥落和粘结磨损现象越严重,涂层剥落和粘结磨损现象在切削速度为500 m/min时最严重,而后随着刀具温度的降低而减缓,切削速度600 m/min时的涂层剥落和粘结磨损现象相比500 m/min时有所减轻。结论断续切削过程中,刀具持续性地经受"负载-卸载"、"升温-降温"产生的高温、冲击和加工环境的不稳定性,是引起粘结现象、涂层剥落和刀具磨损的主要原因。涂层剥落和粘结磨损是导致铍铜合金断续切削刀具失效的主要磨损形式。

The work aims to investigate the effects of temperature variation on tool adhesion, coating peeling and tool wear during intermittent machining. An experimental platform based on intermittent turning which imitated milling process was built. The cutting temperature of the flank at different cutting speed during intermittent machining was measured by thermocouple method, the wear morphology of the flank changing with cutting speed was observed by scanning electron microscopy(SEM) with energy dispersive spectroscopy(EDS) and the element composition of the tool wear area was analyzed. The relationship between the flank temperature and tool wear was described and the flank wear mechanism of TiAlN coated cemented carbide tools in intermittent machining of beryllium copper alloy C17200 was investigated. The tool temperature showed a peak at v=500 m/min with the increase of cutting speed. The higher the temperature was, the more severe the coating peeling and adhesive wear on the flank were. The coating peeling and adhesive wear were the most severe at a cutting speed of 500 m/min. Then, this phenomena slowed down as the tool temperature decreased. Coating peeling and adhesive wear at a cutting speed of 600 m/min were reduced compared to that at 500 m/min. The high temperature, impact and instability of processing environment generated by the tool continuously subjected to "loading-unloading" and "heating-cooling" during intermittent machining process are the main causes of adhesion phenomenon, coating peeling and tool wear. Coating peeling and adhesive wear are the main wear form leading to tool failure in intermittent machining of beryllium copper alloy.