1. Wear mechanism of coarse grinding bin liner plate and the selection of wear-resistant materials
The abrasive degree of coarse grinding bin is 15mm-25mm, the average spherical diameter of grinding body is φ 75mm, and the maximum spherical diameter is φ 90mm-l OOmm. When the mill turns, the ball and the material cut the lining plate with large impact force; the ball squeethe material in the falling sliding or rolling, so the wear mechanism of the rough grinding liner is mainly based on high stress impact cutting wear, supplemented by extrusion cutting.
Crude grinding bin lining plate requirements material has sufficient toughness, cutting wear requirements material with high hardness. According to the wear principle, the material hardness (Hm) shall be more than 0.8 times of the material hardness (Ha), namely Hm / Ha 0.8, and the hardness of cement clinker is HV 500-550, equivalent to HRC 49-54. Therefore, the hardness of the lining plate material should be above HRC 50. Due to the high stress impact chisel, the impact toughness ak 10J / cm2 can not crack, to meet the use requirements. Therefore, the coarse grinding bin lining plate should be selected medium carbon chromium alloy steel and similar alloy steel material, hardness HRC 48-55, impact toughness akl 5-20J / cm2, service life up to 2-3 years. For single screw hole liner and groove liner, choose high chromium cast iron according to relevant standards, and the service life can reach 4-6 years. For large mill liners above φ 3m, should choose high toughness high chromium cast iron, hardness HRC 58-62, impact toughness ak8-12J / cm2, service life up to 6-10 years.
2. Wear mechanism of fine grinding village board and selection of wear-resistant materials
The material entering the fine grinding bin through the partition board has become thinner, and the sharp Angle has become blunt. The diameter of the ball or segment in the fine grinding bin is only φ 15mm-60mm, and the impact force is small, so the wear mechanism of the thin grinding bin liner is the stress cutting wear of the ball.
Fine grinding bin lining plate can choose high hardness, low toughness of wear-resistant materials. Such as high carbon alloy steel, high, medium and low chromium cast iron, anti-wear ductile cast iron and other materials, hardness HRC> 50, impact toughness ak4-6J / cm2 can be used.
Mill lining plate should not choose high manganese steel. For the coarse grinding warehouse, because the yield strength of high manganese steel is low, it is easy to produce plastic deformation, the long size of the lining plate will occur convex deformation, and the impact of the steel ball can not fully produce processing hardening, so it is not wear-resistant. The impact force of the fine grinding bin lining plate is smaller, and the wear resistance of high manganese steel can not be played.
3. Selection of wear-resistant materials for grinding head end lining plate, compartment plate and branch grate plate
(1) Wear mechanism of grinding head end liner plate and the selection of wear-resistant materials
The village board of the grinding head is at the feeding end of the coarse grinding bin, the average particle size of the grinding body is large, and the side impact of the grinding ball and the material is large, which is a wear mechanism of high stress impact cutting wear and supplemented by cutting erosion. Therefore, the grinding head end lining plate should choose the materials with high toughness and impact resistance, high hardness and cutting resistance. Before the use of high manganese steel, because the impact is not enough to fully make its processing hardening, the hardness can only reach about HB 350, by the material cutting erosion wear is serious, the service life is low. If you choose the medium carbon multiple alloy steel lining plate, hardness HRC 46-50, impact toughness ak5 J / cm2, the service life can be double that of high manganese steel.φ
