加压内冷却砂轮的研制及磨削性能研究

针对高温合金材料在磨削加工过程中存在磨削烧伤问题，为避免气障效应并强化冷却液在磨削弧区的换热效果，提出采用加压式内冷却断续磨削方法。利用数值模拟方法和3D打印技术对砂轮基体、加压内冷却系统和密封结构等进行设计和验证，制备了用于平面磨削的加压内冷却开槽CBN砂轮。在相同的磨削加工参数条件下，使用加压内冷却方法与外部喷射冷却方法进行镍基高温合金磨削对比试验，分析了砂轮速度、磨削深度和工件进给速度等加工参数对磨削温度、加工表面粗糙度和表面形貌的影响规律，验证了加压内冷却断续磨削方法对磨削弧区的强化换热效果。结果表明：在相同试验参数条件下磨削镍基高温合金，加压内冷却法比外部喷射冷却法的换热效率更高，得到的磨削温度更低，表面粗糙度更小，加工表面更为光滑细腻。

Development and Grinding Performance of a Pressurized Internal Cooling Slotted Grinding Wheel

In view of workpiece burnout in grinding of superalloy material,the intermittent grinding technology and pressurized internal-cooling method are combined and proposed to avoid the air barrier effect and then strengthen the heat transfer effect of coolant in grinding contact zone. The grinding wheel body,internal cooling system and the sealing structure are designed and verified based on numerical simulation method and 3D printing technology,subsequently a slotted CBN grinding wheel with pressurized internal-cooling system in surface grinding is prepared. Grinding experiments for nickel-based superalloy with different cooling methods,i.e. pressurized internal-cooling method and external spraying method,are carried out under the same grinding parameters. The influence of wheel method,grinding depth and workpiece feed rate on grinding temperature,surface roughness and surface topography are studied,the heat transfer enhancement of pressurized internal-cooling method in grinding contact zone is validated. The results indicate that using slotted grinding wheel with pressurized internal-cooling system can effectively enhance the heat transfer efficiency,reduce the grinding temperature and surface roughness,furthermore leads to better surface topography.