车削参数对高强度耐磨铝青铜表面质量的影响

Effects of Cutting Parameters on Surface Integrity of High-Strength Wear-Resistance Aluminum Bronze

铝青铜合金是一种难切削材料.采用YBC251涂层(TiN/Al2O3/TiCN)硬质合金刀具对一种高强度耐磨铝青铜合金进行干车削实验,利用数显显微硬度计和盲孔法分别测量了被车削工件的表面硬度和表面轴向、环向残余应力,表征了不同车削参数(切削速度、进给量和切削深度)对高强度耐磨铝青铜合金表面完整性的影响情况.研究结果表明:进给量对表面硬度的影响最大;中等切削速度条件下,形成的积屑瘤导致轴向残余拉应力和环向残余压应力随着切削速度的增加,分别呈先增大后减小和先减小后增大的趋势;在较低的切削深度条件下,刀尖圆弧导致表面硬度较低;在较低的进给量条件下,刀尖圆弧使环向残余应力表现出残余压应力.

Aluminum bronze is a difficult-to-machine material. A kind of high - strength wear - resistance aluminum bronze was cut with YBC251 coated （TiN/Al2O3/TiCN） cemented carbide tool. Surface micro- hardness and axial residual stress, hoop residual stress of the machined workpiece were measured by a digital micro-hardness tester and a blind bore method, respectively. Effects of cutting parameters （cutting speed, feed rate and cutting depth） on surface integrity of the machined workpiece were analyzed. The results show that feed rate has a stronger effect on the surface micro-hardness than cutting speed and cutting depth. At medium cutting speed, the formation of built-up edge result in the phenomenon that with cutting speed increasing, the axial residual tensile stress initially increase and then decrease, and the hoop residual compressive stress firstly decrease and then increase. Under the conditions of lower cutting depth and lower feed rate, the tool nose curvature result in much lower surface hardness and hoop residual compressive stress, respectively.