Abstract: In order to improve the anti-fatigue performance of 18CrNiMo7-6 gear steel, high-speed tangential turn-milling experiments were conducted. Results show that with high-speed tangential turn-milling, the three-dimensional surface roughness value Sa are close to those with grinding. The influences of workpiece rotating speed nw and milling cutter rotating speed nc on Sa are significant. The Sa decreases with the increase of nc, and increases with the increase of nw. There are residual compressive stresses on the machined surfaces of high-speed tangential turn-milling(up milling). The nc and axial feed fa have significant effects on surface residual stress. With the increase of nc, the axial residual stress σx and the tangential residual stress σy show the trends of increasing at first and then decreasing, and with the increase of fa, σx and σy decrease significantly. The maximum residual stress appears on the machined surfaces, decreases gradually within 40~60 μm thickness from the machined surface and then stabilizes. The fa has the greatest overall impact on the surface integrity and the surface integrity deteriorate rapidly with the increase of fa. Under the orthogonal test conditions of high-speed tangential turn-milling, the optimal test parameter combination obtained is as nc=6500 r/min, nw=75 r/min, fa=0.02 mm/r, radial depth of cut ap=0.1 mm. Under the conditions of optimal cutting parameters, the Sa is as 0.30 μm, σx is as -400.5 MPa, σy is as -415.9 MPa, and the depth of residual stress affected layer is as 60 μm. The surface integrity with high-speed tangential turn-milling is better than that with conventional turning. The cutting method herein provides a better machining method for machining external cylindrical surfaces.

Key words: 18CrNiMo7-6 steel, high-speed tangential turn-milling, surface roughness, residual stress, conventional turning

摘要： 为提高18CrNiMo7-6齿轮钢的抗疲劳性能，进行了高速切向车铣试验。结果表明：高速切向车铣可获得接近于磨削的三维表面粗糙度Sa，工件转速nw和铣刀转速nc对Sa的影响较为显著，且Sa随着nc的增大而减小，随nw的增大而增大；高速切向车铣（逆铣）已加工表面均为残余压应力，nc及轴向进给量fa对表面残余应力有显著影响；随着nc的增大，轴向残余应力σx和切向残余应力σy均呈先增大后减小的趋势，随着fa的增大，σx和σy显著减小；最大残余应力出现于已加工表面，且在距已加工表面40~60 μm之内逐渐减小，之后趋于稳定；轴向进给量fa对表面完整性综合影响最大，随着fa的增大，表面质量迅速变差。在高速切向车铣正交试验条件下，得到的最优试验参数组合为：nc=6500 r/min，nw=75 r/min，fa=0.02 mm/r，径向切深ap=0.1 mm。在最优参数切削条件下，Sa为0.30 μm，σx为-400.5 MPa，σy为-415.9 MPa，残余应力影响层深度为60 μm。高速切向车铣获得的表面完整性优于传统车削，该切削方法可为外圆表面的加工提供一种更好的加工方式。

关键词: 18CrNiMo7-6钢, 高速切向车铣, 表面粗糙度, 残余应力, 传统车削