High Speed Grinding Of Nickel Superalloy Using CBN Wheels

Nickel superalloy is always used as long-term working crucial elements in high temperature and complex stress condition. In order to get excellent material property, all kinds of elements are added to the material and some reinforcing processes are taken in the process of manufacturing. The excellent properties of the material are improved; however, this also makes the machining (grinding) property very bad. In this condition, it is hard to meet the requirement of machining by traditional grinding wheels. While CBN abrasive grains are widely used in grinding for its excellent properties of high hardness, high intensity and high chemical inertness.In this paper, three kinds of CBN wheels, vitrified bonded, electroplate and brazing wheels, are used to carry out some high speed grinding experiments of GH4169 superalloy. The grinding force, grinding temperature and surface integrity in the grinding process are researched. We are about to get the appropriate wheel and grinding parameters that fit for nickel based superalloy grinding in different condition by comparing the different grinding properties of these three grinding wheels, thus reduce the cost of grinding and improve production efficiency. The main research work completed as follows:(1) Some high speed grinding of GH4169 nicked based superalloy experiments are carried out using three kinds of CBN wheels, vitrified bonded, electroplate and brazing wheels. Grinding force and temperature are measured in the process of experiment. The influencing rules of grinding parameters to grinding force, force ratio, temperature and specific energy are analyzed, and based on this, the relation between specific energy and chip thickness of single grain.(2) Typical grinding processes are selected, and metallographic specimens are made. The variation of metallographic organization is observed, and the micro-hardness of the specimen is also measured. By this, the thickness of affected layer and the degree of burn are determined.(3) On the premise of good surface quality, grinding parameters are discussed and optimized by considering grinding force, temperature and the condition of the wheels. Finally, on the base of theoretical analysis, some high efficiency deep grinding are carried out using some parameters of high material removal rates. What's more, an formed grinding of narrow and deep slot are carried out, and get a good effect.