Investigation On The Processes And Mechanisms Of Diamond Cutting Ferrous Metals

Diamond tools are subject to catastrophic wear in conventionally machiningferrous metals. In order to reduce wear, an integral solution was proposed in thisdissertation, i.e., the combination of surface modification, development of novelsuitable-for-diamond-cutting material and ultrasonic vibration assisted cutting.Extended investigation was also conducted on tungsten carbide, an ideal moldmaterial for precision glass molding by using the developed ultrasonic vibrationcutting system. The main research works and conclusions are summarized as follows:1. Workpiece surface modifications were further studied by investigating newpenetrated elements. It is found that N is beneficial to improve the tool life; N, Siand Al may help to obtain an optical quality surface; B plays the negative role indiamond machinability of steels. This would be useful for developing novelsuitable-for-diamond-cutting materials on which nanometric surface finish can beachieved.2. Deeper nitriding process was explored and the diamond turnability of nitridedpure iron was conducted. It is found that the compound layer of Fe2-3N and Fe4Nhas the potential to be diamond machined to a mirrorlike surface.3. A novel material, powder-sintered FexN (or compounded with some otherelements like aluminum to reduce pores), was proposed on which nanometricsurface quality can be obtained by diamond cutting.4. Molecular dynamics simulation was used to investigate the physical effect ofwater as lubricant and the effect of separation duration of ultrasonic vibrationcutting on diamond tool wear and surface quality.5. The diamond turnability of STAVAX stainless steel was investigated by using thenovel developed ultrasonic vibration cutting system. The effects of processparameters on diamond tool wear and surface quality of the workpieces withdifferent profiles and dimensions were investigated and surface roughness within10nm with no clear tool wear was obtained by using the optimal parameters.6. Extended investigation was also conducted on tungsten carbide by using thedeveloped ultrasonic vibration cutting system. Surface roughness within10nmwas obtained but with some abrasive wear and microchipping in the diamond tool.To solve the problem, an inclined ultrasonic vibration cutting with negative rake angle was put forward.