The Research On Super High Speed Grinding Technology In YG8and PA30Cemented Carbide

Cemented carbides have a prosperous prospect on account of its excellent properties such as high hardness, high wear-resistance and good toughness. Those have been used extensively in industry cutting tools, drilling and mining equipment, molds and dies, and bearings or seals exposed to polluted water. However, these properties also limited the further application of cemented carbides, as these create a challenging problem in grinding. Examples of such challenging problems are lower machining efficiency and higher cost. This paper project thus aimed at developing a super high speed grinding technology for efficiency machining of cemented carbides, and investigating deeply the associated removal mechanisms, which contributes to promote a wider application in the engineering field.Firstly this thesis introduces the traditional process of cemented carbides, and the super high speed grinding technology studies in domestic and abroad. These proved the feasibility and significance of ultrahigh speed grinding cemented carbides. Then the experiment scheme of ultrahigh speed grinding cemented carbides has been introduced in detail. This paper analyze the effects of grinding process parameters, diamond wheel characteristics, coolants and physical-mechanical properties of the cemented carbides on its grindability and grinding regular pattern. There are tow classical cemented carbides, varies wheels and coolants were chosen in grinding experimental. Grinding forces are measured with a force dynamometer-Kistler. The ground workpiece surfaces for information on surface integrity and material-removal mechanisms, etc. are evaluated by scanning electron microscopy (SEM) and surface profiler. The influence of grinding forces and specific grinding energy on diamond wheel characteristics, physical-mechanical properties of the cemented carbides, coolants and grinding process parameters have been investigated. The material-removal mechanisms have been analyzed on the alteration of grinding force special grinding energy surfaces topography and roughness.The experimental results indicate that the material-removal mechanisms of cemented carbides mainly influenced by grinding process parameters, when ductile grinding of cemented carbides. Increase in cutting speed causes grinding forces and force ratio decrease, finer surface roughness and the trend of plastic flow increase. When the feed rates or the depth of cut is increased, the grinding force and forces ratio are increased, the surface ground topography is deteriorated and the brittle fracture is dominated. Meanwhile, compared with the vitrified-bonded diamond wheel, the resin-bonded diamond wheel will lead to the better surface roughness and the larger grinding forces. Due to YG8higher hardness and lower toughness, its critical depth of ductile and brittle transition is relatively lower. The material removal of brittle fracturing is dominated during grinding. The lubrication of emulsification coolant is more significant than traditional coolant and well achieves the finer grinding ground.