CBN砂轮磨削镍基高温合金磨削温度实验研究

Experimental research of grinding temperature during grinding of nickel-based superalloy with CBN wheel

磨削高温是限制磨削技术发展的主要瓶颈之一,因而研究磨削过程中产生高温的机理及磨削温度的变化规律十分重要。采用260 mm的单层钎焊有序排布CBN砂轮,对镍基高温合金GH4169进行不同速度下的磨削实验。实验过程中,保持砂轮线速度和工件进给速度的比值不变,从而保持单颗磨粒最大未变形切屑厚度不变,发现比磨削能得到有效控制,磨削温度的上升主要由材料去除率的提高所导致;随着砂轮线速度的增加,磨削弧区热量分配关系发生显著变化,传入工件的能量增加;磨粒排布方式对传入工件的热量有影响,同一磨削工艺参数下,磨粒斜排布的砂轮磨削温度要低于磨粒直排布的砂轮,最佳磨粒排布方案还有待进一步的研究。

High grinding temperature is one of the main limitations to the development of grinding technology, so it is very important to study the mechanism and regularity of grinding temperature. In this experiment, the monolayer brazed CBN wheel （Ф260 mm） was used for grinding nickel-based superalloy GH4169 at different grinding speed from 20 m/s to 100 m/s. The ratio of the grinding wheel speed to work speed was kept as a constant value, thus the undeformed chip thickness kept constant. It was found that, the specific grinding energy was effectively controlled, that means high grinding temperature was mainly caused by enhanced removal rate of material rather than high specific grinding energy. This conclusion is quite different from what we usually thought before. The partition of grinding heat transferred to the workpiece was drastically increased with enhanced grinding speed; The pattern of abrasive grains also influenced the heat partition, the grinding temperature of CBN wheel with obliquely arrayed abrasive grits was lower than that with straightly arrayed abrasive grits under the same grinding parameters. Much more research is needed to confirm the best distribution of abrasive grains.