汽轮机转子材料20Cr2NiMo铣削加工表面残余应力研究

Research on Surface Residual Stress By Milling 20Cr2NiMo Used for Turbine Rotors

零件加工表面残余应力对零件的疲劳强度和抗腐蚀性能具有重要影响。本文基于均匀试验方法,以切削速度、每齿进给量和轴向切深为因素,对汽轮机转子材料20Cr2NiMo合金钢进行铣削试验。通过测量不同切削参数下已加工表面的残余应力,采用多元回归方法建立了表面残余应力与切削参数之间的关系模型并得到验证。研究结果表明随着切削速度、每齿进给量和轴向切深的增大,残余拉应力均呈增大趋势;切削参数对表面残余应力的影响程度为v>f z>a p,且三因素之间存在交互作用。最后根据影响规律,为使加工表面呈现压应力状态,给出了切削参数的建议范围。

Surface residual stress is an important factor on fatigue strength and corrosion resistance of workpieces. The testing scheme was designed for turbine rotor material, 20Cr2NiMo, using by uniform experimental method, and cut- ting speed, feed per tooth and depth of cut are taken as the factors. The residual stress of machined surfaces was measured for different cutting parameters. The relationship between residual stress and cutting parameters was established by multi - variables regression method. The results show that residual tensile stress increases with cutting speed, feed per tooth and depth of cut ; and the degree importance ranks as v 〉 f〉 ap. The interactions of cutting parameters are also found. In addi- tion, cutting parameters suggested are provided in order to acquire compressive residual stresses of workpieces.