Research On Grinding Process Of Nano-grained Cemented Carbide GU092

Tungsten carbide nano-grained cemented carbide with a grain size of less than 0.2?m has very superior physical and mechanical properties,and is widely used in engineering fields with high wear resistance and high thermal stability requirements,processing of difficult-to-process materials,and rock drilling Mining and other aspects.However,the superior physical and mechanical properties also bring difficulties to the grinding of nano-grained cemented carbide,such as excessive grinding force and large grinding wheel wear during the processing.Grinding is a process of high energy consumption,which conflicts with the concept of green development of the manufacturing industry.At this stage,the research on nanocrystalline cemented carbide mainly focuses on the preparation and synthesis of materials.Therefore,this paper takes the typical representative of nano grain cemented carbide GU092 as the research object The grinding process and grinding mechanism of this material have been studied.The following is a summary of the main work of this paper:1.In this paper,three materials of cemented carbide are studied,which are nano-grain cemented carbide GU092,sub-micron cemented carbide GU20,and ordinary coarse-grained cemented carbide YG8.Under different grinding parameters,the resin bond diamond grinding wheel is used for surface grinding,and the grinding force and power in the grinding experiment are collected.The grinding parameters(grinding depth a_p,workpiece feed speed v_w,grinding wheel linear speed v_s),material removal rate Q'_w,the maximum undeformed chip thickness h_maxof a single abrasive grain,and different tungsten carbide WC grain sizes are analyzed.The influence of grinding force,grinding force ratio and grinding specific energy is analyzed by using ternary nonlinear regression method and an empirical formula model is established.The study found that,compared with the other two cemented carbide materials,the grinding force and specific grinding energy of nano-grain cemented carbide GU092 are both small,and the grinding force ratios of the three materials are not much different,both in 2.5?3.2.between.The unit width tangential F'_tand the normal grinding force F'n are negatively correlated with v_s,and positively correlated with a_pand v_w.The primary and secondary relationships of the three elements of grinding on the grinding force are as follows:a_p>v_w>v_s.Grinding force ratio and grinding specific energy have a negative correlation with v_s,and a positive correlation with a_pand v_w.The primary and secondary relationship of the three elements of grinding on the specific energy of grinding is as follows:v_w>v_s>a_p.When the material removal rate is fixed,the small cutting depth and large feed grinding combination can not only reduce the grinding force during the grinding process,but also reduce energy consumption.In addition,the BP neural network and the GA-BP neural network are used to predict the grinding force.The comparison results show that the GA-BP neural network has a smaller error in predicting the grinding force and the model is more accurate.2.The surface roughness of the workpiece after grinding and the residual stress value of the workpiece surface were measured by the Marr roughness meter and X-ray diffractometer,and the surface micro morphology of the workpiece was observed by scanning electron microscope.The effects of the three elements of grinding and the grain size of tungsten carbide on the surface roughness,residual stress and surface micromorphology of the workpiece are analyzed.The results show that the nano-grain cemented carbide is compared with the other two cemented carbides.The surface roughness value and residual stress value of granular cemented carbide are relatively small.The grinding process is mainly based on the removal of material shaping,supplemented by plastic removal.Surface roughness and residual stress on the surface of the workpiece are positively correlated with a_pand v_w,and negatively correlated with v_s.The primary and secondary relationship of the influence of the grinding amount on the surface roughness of the processed workpiece is:v_w>v_s>a_p.The primary and secondary relationship of the degree of influence of the grinding amount on the residual stress on the surface of the workpiece is:a_p>v_s>v_w.3.Considering that the grinding process is a process of high energy consumption,based on the gray correlation theory,the grinding specific energy,surface roughness,and residual stress are orthogonally optimized with multiple indicators.The comprehensive scoring method is used to weigh the relationship between the three,and the experimental parameters are obtained.Within the range,the optimal combination of grinding parameters that takes into account surface quality and specific grinding energy is a_p=25?m,v_w=40mm/s,and v_s=15m/s.