The Study On Impact Tribology Characteristics Of Shot Blasting Machine Blades

Shot blasting(enhancement)has been widely developed in recent years due to its advantages of high efficiency,low consumption,low labor intensity,and automation.The shot blasting machine blade is the most prone to wear failure in the blasting machine,and its service life will directly affect the shot blasting efficiency.Therefore,it is important to study the influence of various parameters of the blade on the wear of the blade and develop an anti-wear and wear-resistant shot blasting machine blade.In this paper,the mathematical models of projectiles acceleration and contact on the blade were constructed.The cooperation mode of four blades matrix and powder metallurgy sheet were designed,and the three-dimensional model was established,and then the modal analysis was carried out.The powder metallurgy samples were prepared by using niobium carbide(HfC)as the reinforcing phase and tungsten carbide(WC)as the matrix,and the mechanical properties were tested and analyzed.The microstructure of the specimen after friction and wear of the ring block and the impact friction and wear were observed,and the blade wear was verified under the actual working conditions.Finally,the acceleration process of the projectiles on the blade were simulated and verified.This paper constructed mathematical models for the acceleration and contact of projectiles on the blade.The projectile was simplified into a mass point,and the various states and acceleration processes of the projectile on the blade were analyzed.It was found that the frictional force of the blade was positively correlated with the outer diameter of the blade,the rotational speed of the splitting wheel,the friction coefficient of the blade surface and the mass of the single projectile;The contact mechanics was used to analyze the process of the projectile contacting the blade.It was found that the pressure between the blade and the projectile was proportional to the velocity of the projectile,the mass of the projectile and the elastic modulus of the blade,And it was inversely proportional to the particle size and incident time,and negatively related to the contact radius.This has important guiding significance for the design of the blade structure and the choice of materials.The matching method of four blade bases and powder metallurgy sheets were designed,and a three-dimensional model was established.The workbench was used to analyze the force of the blades under the impact of the projectiles,and then the coordination modes were optimized.The results show that the optimized stress concentration of the combined blade is significantly reduced and meets the bearing requirements.Powdered metallurgy samples were prepared by using cesium carbide(HfC)as the reinforcing phase and tungsten carbide(WC)as the matrix,ball milling,cold forming and hot pressing sintering.It was found that its relative density,hardness,flexural strength and fracture toughness were significantly improved,and its improvement mechanism was analyzed.It was found that it enhanced the mechanical properties of the material by increasing the crack propagation resistance(such as crack straight,crack deflection,crack bifurcation,and crack pinning).The microstructure of the specimen after friction and wear of the ring block and the impact friction and wear were observed,and the blade wear under actual conditions was verified.After the friction and wear of the ring block,under the same rotation speed and load,the friction factor and the wear amount of the sample material increase first and then decrease with the increase of HfC content,and the friction factor is between 0.33 and 0.51.When the mass fraction of HfC is 1.5%,the wear amount is at least 0.038%;When the impact friction is worn,it is found that when the incident angle is small,the blade mass loss is mainly manifested in the furrow and shallow grain spalling phenomenon.When the mass fraction of HfC is 1%,the wear is minimal.When the incident angle is large,the microcracks and the number of the surface of the sample are obviously increased.The mass loss is mainly manifested in the pit and shallow grain spalling phenomenon.When the mass fraction of HfC is 0.5%,the wear is minimal;The wear test under actual working conditions shows that the WC/Co/HfC combined blade can significantly improve the blade life.The simulation of the acceleration process of the projectiles on the blade are carried out.It is found that the acceleration process of the projectiles in the blasting machine can be divided into gravity acceleration period,sudden rise period and stable shot blasting period according to the speed change speed.The projectiles throwing speed are positively correlated with the speed of the splitting wheel,the length of the blade and the particles size of the projectile,and has nothing to do with the initial velocity of the projectile;The initial velocity and the particle size of the projectile can effectively shorten the gravity acceleration period of the projectile,while the speed of the splitting wheel and the length of the blade have no significant effect on the various periods of projectile acceleration,which is consistent with the theoretical analysis of Chapter 2.