Abrasive wear: in the process of friction, wear debris or protruding material loss of surface material. Abrasive grains generally refers to non metallic materials, such as quartz, coal, rock and sand, etc.. Hard metal particles or projections on the soft metal will cause wear, such as the friction between the pair into the process of hardening of the wear debris will occur abrasive wear. It can cause wear and tear, which is common in coal mine machinery.
The mechanism of abrasive wear is mainly:
1, micro cutting, namely the hard grinding grain like tool on the surface of the parts are extremely small cutting and chip formation;
2, grinding particle is round or inappropriate and parts of the surface of the relative angle, only on the surface of furrows, the surface material pile to both sides and the front, after repeated plastic deformation fracture and spalling of material surface;
3, brittle fracture, brittle material wear generally this is the case.
The factors affecting the abrasive wear are the internal factors and the external factors of the material. Internal factors that affect the maximum is the material hardness.Generally speaking, the hardness of part material (correctly said that the surface hardness after the material wear), the higher the wear resistance. The wear resistance is proportional to the hardness of pure metal and annealed steel. After heat treatment of steel, the wear resistance increases with the increase of hardness, but the degree of improvement is slightly lower. For the materials such as quartz and ceramic, high hardness, high hardness, wear resistance, but decreased, which is due to the decline in fracture toughness, prone to brittle fracture so that wear and tear. The influence of the external factors is the ratio of the Hm to the hardness of the parts and the hardness of the Ha. When Hm/Ha > 0.8, the wear resistance of the parts is increased rapidly; when the Hm/Ha is less than 0.8, the wear resistance of the parts is low. The former is called soft abrasive wear,the latter is called hard abrasive wear.Therefore, in order to improve the wear resistance of the material, the hardness of the material must be more than 80%, which is a key problem of choosing materials.