立方氮化硼砂轮磨削电瓷瓷套残余应力分析

Residual Stress Analysis of Grinding Electric Ceramic Insulators by Cube BN Grinding Wheel

采用立方氮化硼砂轮磨削电瓷瓷套表面,用X射线衍射法(XRD)分析了其表面所产生的残余应力。结果表明:经立方氮化硼砂轮磨削后电瓷瓷套表面所产生残余应力为拉应力,大小为165·1MPa。电瓷中成分较为复杂(含有玻璃体、多晶体和少量气孔相),主晶相为刚玉(Al2O3),次晶相为石英(SiO2),含有少量的莫来石(3Al2O3·2SiO2)。电瓷原料中引入的Ti4+、K+、Na+、Ca2+、Mg2+离子主要存在于玻璃体中,并不固溶于晶相。由于电瓷表面的残余拉应力往往会造成其断裂强度下降,从而导致电瓷瓷套表面容易出现裂纹、崩边和豁口等现象,所以有效控制和降低电瓷表面磨削残余应力就显得非常重要。

The cube BN grinding wheel was adopted to grind electric ceramic insulator, and the residual stress of insulators was analysed by the X-ray diffraction （XRD） technique. The results show that the residual stress of insulators is tension stress and its value is about 165. 1 MPa. The compositions of insulators are very complex （containing the vitreous-body, heteromorphism and a little pore）. The main-crystal phase is corundum （Al2O3 ）, hypo-crystal phase is quartz （SiO2 ）, and with a little limestone （3Al2O3· 2SiO2）. The ions of Ti^4＋ , K^＋ , Na^＋ , Ca^2＋ , Mg^2＋ are imported by the raw material, which mainly distribute in the vitreous body and don＇t dissolve in the crystal phases. The bend strength is decreased by the residual stresses in the insulators, which induces many microcracks, crashed failure near the borders of insulators and breach phenomena etc, so it is very important to control and reduce the residual stresses in insulators.