陶瓷结合剂金刚石砂轮磨削超细晶粒硬质合金的表面粗糙度研究

本文结合单因素实验和正交实验,研究了从低速到高速磨削条件下,砂轮速度、进给速度、磨削深度、最大未变形磨削厚度以及磨削方式(顺磨或逆磨)对陶瓷结合剂金刚石砂轮磨削超细晶粒硬质合金表面粗糙度的影响规律,分析了影响超细晶粒硬质合金表面加工质量的原因。研究表明,总体来说磨削参数的变化对超细晶粒硬质合金表面粗糙度的影响程度不大。高速磨削时的表面粗糙度相比低速磨削得到了比较明显改善。逆磨时的粗糙度比顺磨大,随砂轮速度增加下降更快。相比传统硬质合金,磨削WC颗粒更细、强度更高的超细晶粒硬质合金的表面粗糙度更低。磨削参数对表面粗糙度的影响程度从小到大依次是磨削深度、砂轮速度和进给速度,实际加工时为同时获得较高的磨除率和表面质量,宜采用高砂轮速度、低进给和大切深的磨削组合。

Experimental Research on Surface Roughness of Ultrafine Grain Cemented Carbides Ground with Vitrified Diamond Wheels

This thesis combined the single factor test and the orthogonal test to study the influence of wheel speed, feed velocity, depth of grinding, the maximum undeformed chip thickness and the method of grinding （ down grinding or up grinding） on the surface roughness of uhrafine grain cemented carbides ground with vitrified diamond wheels under low speed and high speed grinding conditions and analyzed the factors that affect the surface quality of ultrafine grain cemented carbides. It was suggested by this study that the influence of grinding parameters on the surface roughness of ultrafine grain cemented carbides is not obvious on the whole. The surface roughness under high speed grinding condition was smaller than that under low speed grinding condition. The magnitude of surface roughness with up grinding method was higher and de- creased more quickly with the increase of wheel speed than that with down grinding. Compared to traditional cemented car- bides, grinding ultrafine grain cemented carbides was easier to get lower surface roughness since it had smaller grain size and higher strength. The influence magnitude of grinding parameters on surface roughness, in the order of smallest to largest, is depth of cut, wheel speed and feed velocity. In order to get better removal rate and surface quality at the same time, grinding combination of high wheel speed, low feed velocity and high depth of cut should be adopted.