Study On The Effect Of Graphite On The Performance Of Metal Bonded Diamond Tools

Metal bonded diamond tools with high bonding strength,good wear resistance and long service life,etc.,occupying a large market in the diamond products,are important in the modern industrial production and development.However,there are still some problems in the metal bonded diamond tools,such as low porosity,poor toughness and self sharpening.This paper chooses graphite as an additive to solve the problems encountered with metal bonded diamond tools.The bonding strength of metal bond matrix and graphite which exist in the free state of the matrix,improve the porosity of the matrix,and play the role of making chip remove,cooling and promoting self-sharpening effect;Graphite can weaken the carcass,matching the wear resistance of the matrix and diamond,and improve the comprehensive performance of the tools.In this paper,the influence factors and the level of graphite were obtained by single variable method,and the wear ratio,mechanical properties,grinding speed and service life of the metal bonded diamond tools were studied by orthogonal test.Analyzing the experimental results,and drawing the following conclusions:(1)Through the analysis of orthogonal test,the order of the effect of the metal bonded diamond tool is as follows: the graphite content is the largest,the graphite type is the second,the graphite particle size is the smallest;(2)Through the analysis of orthogonal test,when the grain size of diamond is70/80 mesh,the best solution for the effect of graphite on the performance of copper-based binder diamond tools is as follows: the graphite type is flake graphite,the graphite particle size is 80 mesh and the graphite content is 3wt%.According to the bestmethod to prepare the experimental sample and test performance,the abrasive ratio of the sample is the largest and the maximum value is 206.62,which is 43.12% higher than that of the reference sample;Compared with mechanical properties of the reference sample,The flexural strength and hardness are reduced by 32.98% and 16.13%respectively,while the impact strength is improved by 5.67%.(3)Through the analysis of orthogonal test,when the grain size of diamond is70/80 mesh,the best solution for the effect of graphite on the performance of iron-based binder diamond tools is as follows: the graphite type is crystalline graphite,the graphite particle size is 120 mesh and the graphite content is 3wt%.According to the best method to prepare the experimental sample and test performance,the abrasive ratio of the sample is the largest and the maximum value is 287.58,compared with the reference sample,the increase of the abrasive ratio of the sample is about 3.30%;Compared with mechanical properties of the reference sample,the flexural strength and impact strength are reduced by 34.16% and 21.65% respectively,while the hardness is almost unchanged.(5)The service life and the sharpness of the metal bonded diamond tools are in the opposite direction,and the sharpness of the tool and the grinding speed will be increased,and the service life will be reduced.Compared with the standard grinding wheel,the maximum grinding speed of the copper-based grinding wheel with graphite increases by 7.89% with the service life reducing by 20.63%;and the maximum grinding speed of the iron-based grinding wheel with graphite increases by 6.99% with the service life reducing by 19.28%.In the experiment,although the service life of the metal bonded diamond tool is reduced,the tool is sufficient to meet the requirements of production.More importantly,the sharpness and grinding speed are enhanced,the grinding quality of grinding area is improved and range of application of metal bonded diamond tools is expanded by reducing the service life of mental boned diamond tools.