摘要
TB6高强度钛合金因其优良的比强度和热变形性能被广泛应用于航空领域,是制造直升机旋翼系统主承力结构件和起落架的主要材料。为了使零件获得较佳的疲劳性能,基于加工后的表面完整性指标对其精铣加工参数进行了优选。试验结果表明,每齿进给量f_z对加工后的表面粗糙度R_a和表面残余压应力σ_H有较大影响,随着每齿进给量f_z的不断增大,表面粗糙度R_a近似线性增大,表面残余压应力的幅值也随之增大;线速度v_c主要影响加工表面显微硬化率,显微硬化率随线速度的增大而降低;径向切宽a_e对加工表面残余应力也有较大的影响,随着a_e的增大,加工表面残余压应力的幅值逐渐降低。因此,从提高零件疲劳寿命的方面考虑,在满足例如零件表面质量要求和生产效率等各项生产要求的前提下,应尽可能降低铣削线速度,减小径向切宽,提高每齿进给量,适当选择轴向切深。
TB6 titanium alloy is widely used in aviation because of its high strength-to-weight ratio and extraordinary hot deformation behavior, which is the main material to manufacture the primary structure of helicopter rotor systems as well as the landing gears. To ensure the parts meet the requirement of fatigue properties, finish milling parameters have been optimized based on the integrity of machined surface. The experiment results show that feed per tooth fz has an obvious influence on the roughness Ra and residual stress σH of the machined surface. When fz increases, the surface rough- ness increases linearly. Meanwhile, the amplitude of the residual stress also increases with the increase of fz. The micro- hardening rate is mainly effected by the cutting speed vo. The increase of vo leads to the decrease of the micro-hardening rate. On the other hand, it can be obtained that the cutting width ae has a great influence on the machined surface residual stress. When ae increases, the amplitude of surface residual stress reduces obviously. According to improving the fatigue properties, low cutting speed vo, small cutting width ao and high feed per tooth fz should be adopted. At the same time, the appropriate cutting depth ap can be utilized under the premise of meeting all the design requirements, such as the surface roughness and machining efficiency.
出处
《航空制造技术》
2017年第1期55-59,共5页
Aeronautical Manufacturing Technology
基金
航空科学基金(2016E51039)
关键词
表面完整性
TB6钛合金
铣削
参数优化
疲劳寿命
Surface integrity
TB6 titanium ally
Milling
Parameters optimization
Fatigue life
