高效切削钛合金时刀具磨损试验分析

针对航空发动机典型零件钛合金膜盘在加工过程中刀具磨损严重、加工效率低的问题，采用未涂层硬质合金刀具进行钛合金外圆车削加工试验研究，利用CCD观测系统和SEM的能谱分析（EDX）研究刀具刃口微观结构变化，分析刀具的磨损形态及不同切削条件和锯齿屑对刀具磨损的影响. 结果表明：钛合金外圆车削加工时，刀具磨损主要为粘结磨损、扩散磨损和氧化磨损，切削速度对刀具磨损影响较大，进给量次之，背吃刀量最小. 随着切削速度和进给量的增加，磨损加剧，锯齿屑的高频形成导致切削力的高频变化，这种高频率的冲击载荷在前刀面上产生应力和温度冲击，使刀具形成微裂纹，加速刀具磨损；使用冷却液可以减轻刀具后刀面粘结磨损和扩散磨损，从而可有效地控制刀具磨损.

Experimental analysis on tool wear during high-efficiency cutting of titanium alloy

In the machining process of titanium alloy membrane disk, a typical aero engine component, the machining efficiency is low and the tool wear is serious. Thus, the uncoated cemented carbide tool was used for the cylindrical turning of titanium alloy. The CCD observing system and EDX analysis of SEM were used to study the micro structural evolution of tool edge, the wear morphology of tool as well as the effect of cutting conditions and serrated chip on tool wear. The results show that the main wear modes during the cylindrical turning of titanium alloy are adhesive wear, diffusive wear and oxidative wear. The cutting speed has the greater influence on tool wear, followed by feed rate and cutting depth. As the cutting speed and feed rate increases, the tool wear becomes more severe. The high frequency formation of serrated chip leads to the high frequency change in cutting force. The stress and temperature shocks generate on the tool rake face because of the high frequency load. These shocks promote the formation of micro cracks and the tool wear. The usage of coolant can effectively control the tool wear through reducing both adhesion wear of tool flank face and diffusion wear.