Experimental Study On High Speed Grinding Of Titanium Alloys (TC4) With Vitrified CBN Grinding Wheel

The titanium alloys are widely used in the aviation, the aerospace, the navigation, the car, the medicine and other industrial fields for their high specific strength, high fatigue strength, non-magnetic, good corrosion and heat resistance. However, the titanium alloys are typical difficult-to-cut materials. There are many problems, such as the high grinding force, high temperature and poor surface quality during the grinding process. High-speed grinding technology can provide high surface quality and grinding efficiency and is called"The Peak of Modern Grinding Technology"as small grinding force, low grinding temperature, little work-piece deformations. Therefore, it is considered as a potential technology for high efficient grinding of titanium grinding and great attentions have been paid on. In the previous studies on high speed grinding of TC4, electroplated CBN wheel were widely used. Due to the improvement of manufacture, great attention has been paid on high speed grinding with the vitrified CBN grinding wheel for its advantages such as good rigid, high sharpness bonding strength, heat resistance and the pore can be adjusted, which is suitable for the processing of ferrous metals and their alloys. Therefore, vitrified CBN grinding wheel is considered to be a potential tool for high speed grinding of TC4.This thesis was undertaken to investigate the forces, power, specific energy, temperatures, energy partition and surface roughness in high speed grinding of TC4 with a vitrified CBN wheel under different grinding parameters. The grinding experiments were conducted on a high-speed grinder (HP408), the grinding forces were measured by a piezoelectric crystal dynamometer and the grinding temperature was measured by sandwiched foil thermocouple. The ground surfaces were inspected by SEM and EDS. The main conclusions derived in this work can be summarized as follows:1. High speed grinding of TC4 with vitrified CBN wheel exhibits low grinding force, grinding temperature, grinding energy partition and fine surface roughness. In the present work, the specific grinding energy is 28.11～124.32J/mm~3, the grinding energy partition is 8.4%～32.8%.2. In high speed grinding of TC4 with verified CBN wheel, grinding depth is the most significant factor to grinding force and grinding speed is the most significant factor to determine temperatures. 3. During grinding at normal speed, many coatings can be found on the ground surface of work-piece, which are causes by the scratching action of abrasive grits. As the grinding speed increases, the material removal mechanism of TC4 is dominant in the plastic way. As a result, surface roughness value decreases.4. For TC4, high-speed grinding with vitrified CBN wheel can greatly improve efficiency under the same conditions of processing quality, which can get a better surface quality under the same material removal rate also.