Dry Grinding And Polishing Of Titanium Alloys

Titanium alloys have more and more applications in many industrial fields especially in aeronautics and astronautics in virtue of their high specific strength, good corrosion resistance and high thermal stability. However, titanium alloys are well known as a kind of difficult to machine material, due to its low thermal conductivity, small elastic module, and high chemical activity. Dry grinding and polishing as the key process of lager structure workpiece of titanium alloys has the decisive influence to the components surface quality. Because of the tools performance and the grinding parameters significantly influence the cost, efficiency and surface integrity, it is significant to develop the innovative belt, cubic boron nitride (CBN) abrasives grinding wheel at the same tine to evaluate the performance of grinding tools with solid lubricants were add into tools improve its machining grindability and ground surface quality for titanium alloys.The main contents in this paper are as follows:(1)The equipment was developed to employ belt in the grinding and polishing of titanium alloys. Grinding temperature was measured by a constantan-workpiece thermal couple. The influences of different parameters on grinding force and temperature by belt dry grinding are studied. This could provide a theoretical basis for the feasibility of machining titanium alloys with belt. The effects of grinding parameters and belt wear status on the surface integrity were investigated. The paper develops the equipment employs flap wheel in the grinding and polishing of titanium alloys, the equipment was to simulate flap wheel hand-held machining to study the grinding ability of flap wheel. The influence of different parameters on machining ability, flap wear, and grinding temperature were studied with flap wheel by dry grinding. Graphite is chosen to prepare the solid lubricant with the binder. Solid lubricant technology has been studied with the grinding flap wheels coated by solid lubricant. Comparative experiments with grinding flap wheels in different solid lubricant parameters were conducted. And the influence of different parameters on grinding temperature and surface roughness were studied.(2)The innovative monolayer brazed cubic boron nitride (CBN) grinding wheels with rhythmed grain distribution were designed and fabricated accronding to the requirements of brazing technique to reliaze the grinding and polishing of titanium alloys. Moreover, on the basis of determined the suitable brazing process, the machining process of the grinding wheel with structural components mainly controlling the rotary accuracy of the wheel and the equal height characteristics of grains was effectively controlled, this kind of ordered-grained CBN grinding wheels which has been applied ground applied to titanium alloys was successfully developed. The grinding performance has been evaluated in the dry grinding process of the titanium alloys. Comparative experiments with grinding CBN wheels in different machining parameters were conducted. And the influence of different parameters on grinding temperature, wheel wear and surface intergrity were studied. The CBN grinding wheels with solid lubricant were prepared successfully. Meanwhile, the grinding temperature and the ground surface of the solid lubricant tools were evaluated.(3)The innovative thought of the grinding wheel and increasing solid lubricant was proposed in order to reduce the intensity of heat source, and thus two new grinding wheels are developed and their performance of dry grinding titanium alloys were evaluated. Multi-layer brazing diamond and CBN grinding wheel were prepared successfully. The strength of grinding wheel meets the application requirements, the gap structure of diamond grinding wheel was well distributed, the graphite of CBN grinding wheel was evenly distributed in the free state, brazing achieved between binder and abrasive. The effects of grinding parameters status on the machining ablity and surface integrity were investigated on dry grinding by super abrasive grinding wheels and SiC wheel.(4) According to the actual processing requirements, the representative lager structural components of titanium alloys was ground and polished with the combination optimization process to verify the result. Finally, the good surface quality was obtained.