Study On Wear And Methods Of Wear Resistance On Crushing Plate Of Jaw Crusher

Based on the aggravation of jaw plate wear of compound pendulum jaw crusher in Xinkaiyuan,wear failure modes of jaw plates were analysed, the key reasons of serious wear of jaw plates were revealed,this paper further analysed the wear laws jaw plates of jaw crusher by simulating crushing ores of jaw plates of jaw crusher with discrete element software EDEM,and to explore the Influence of the crusher nip angle, filling rate and moisture content of the ore on jaw plate wear.Analysis results of surface morphology of the waste jaw plates using optical microscope show that wear mechanism of jaw plates of jaw crusher is chisel cutting wear, fatigue wear and corrosion wear coexistence. Jaw plates are impacted and extruded strongly by ores, surface of jaw plates are chiseled and cut greatly. Jaw plates shows serious plastic deformation including very deep scratch, compact grooves and large area pits. The chisel cutting wear is main wear mode of jaw plates. Jaw plates are impacted and extruded repeatedly in the long term, causing contact fatigue, appearing fatigue crack and crack propagation, resulting in brittle fracture, fatigue wear is one mode of jaw plate wear modes. In addition, the water on ores for on-site suppression dust sprinkler contacts with the jaw plates, presenting complex chemical reactions in the air, causing oxidation corrosion,resulting in jaw surface material turned up and rubbed off, the new metal surface corrosion continuing, exacerbating the wear of jaw plates.Using OBLF-1000-ⅡX-ray spectrometer to detect the chemical composition the moving jaw plates and fixed jaw plates,the alloy elements Mn content is greater than 10%, which means the jaw plates are high manganese steel. The hardness test of wear parts of jaw plates at different depths by HV-1000 micro hardness tester shows that jaw plates have high hardness on the surface and evident hardening gradient in depth,which means that jaw plates have good work hardening effect and high wear resistance.According to GB / T 17412.1-1998 and GB / T23561.7-2009, this paper detected mineralogical composition and compressive strength of ores from two mines,which are before and after mining site changed in Xinkaiyuan. Combined with life of jaw plates, ores which contain more hard phase have the greater compressive strength, being harder broken, causing jaw plate wear faster and life shorter, revealing the main reason on serious wear of jaw plates in Xinkaiyuan is the changes of composition and nature of the feed ores.Establishing crusher geometry model and ore model By discrete element method and EDEM software, according to the PE900 × 1200 compound pendulum jaw crusher and properties of ores from Xinkaiyuan, simulating jaw crusher to break ores, it obtained normal force distribution and tangential force distribution of the moving jaw plate at 1s, 1.5s, 2s, 2.5s in simulation time. Based on the force characteristics in different districts of the moving jaw plate surface the jaw plate is divided into four regions as H, M, ML and L: H is contacting zone of ores feeding, which is primarily impacted by ores with a certain initial velocity. M and ML is the area in which ores are crushed, the ore is broken mainly in this area, being squeezed and cutting together. L is the discharge zone, this area is not only extruded, but also exists sliding friction.Simulation results shows the maximum normal force in different regions on the moving jaw plate: H 1.53 × 104 N, M 6.21 × 106 N, ML 6.65 × 106 N, L 6.33 × 106 N, the maximum tangential force: H9.2 × 102 N, M 4.53 × 106 N, ML 5.78 × 106 N, L 5.98 × 106 N.Comparing the maximum normal force and he maximum tangential force, combined with the analysis on surface morphology of jaw plate wear parts, the H is subjected to a large normal force, which indicates that this region is normally impacted by ore in long term, it is easy to form fatigue crack and appear fatigue wear. M, ML and L are main crushing region on the moving jaw plate, ores are crushed by both compressive stress and shear stress from jaw plates. These regional normal force is greater than the tangential force, indicating jaw crusher is mainly based on the compression to crush ores, and grinding as a subsidiary role. The main wear mode of jaw plates is chisel cutting wear.Simulation the influence of crusher nip angle, filling rate, moisture content of ores on the force of moving jaw plate, H is subjected to greater tangential force with the nip angle becoming smaller, existing significantly cutting action, while M and ML is subjected to greater normal force, existing the more serious chipping wear. With filling rate increasing ML and L of moving jaw plate are subjected to greater tangential force, existing serious cutting wear. The moisture content of the ore hardly influences the force of moving jaw plate. But the corrosion wear caused by water is an important factor in promoting wear of jaw plates development.Through the above analysis programs proposed to enhance the wear resistance of the jaw plates: developing modular jaw plate, combined with H plate, M plate, ML plate and L plate four plates, each plate was determined by the law of the force characteristics in different regions such as different wear resistant material. It can improve chisel cutting wear of jaw plates by decreasing nip angle,which reduces tangential force of jaw plates. The nip angle in jaw crusher is changed by adjusting the width of the discharge. In order to reduce nip angle, it should increase the width of the discharge on the premise of meeting the requirement of particle size. To select the filling rate of jaw crusher should decrease the value on the premise of crusher subjected to reasonable shock and vibration. For improving corrosion wear of jaw plates, it is necessary to decrease water consumption in production. At burning point and crushing ores point by the impact hammer again, it should take mist in replacement of spraying water directly to suppress dust, which is on the premise of effective removal dust minimizing water consumption. It is recommended that dust suppression point is set on blanking to ensure dry-crushing in the jaw crusher.