The causes of serious wear of sprocket chain socket are as follows: (1) The higher the adhesive wear load, the higher the surface temperature, the more serious the adhesion phenomenon.For metal materials with certain hardness, wear tests are carried out under different pressures, and the relationship between wear rate and pressure is obtained. When the pressure reaches more than 1 / 3 of material hardness, serious wear will occur.According to the stress distribution diagram, it can be seen that the contact point of the maximum stress is at the maximum pressure, and its value is 884.4 MPa.Because the quenching hardness of chain socket is hrc48 ~ 52, the corresponding hardness value is 4800mpa.Therefore, the pressure is far less than 1 / 3 of material hardness, so adhesive wear is not the main form of sprocket wear. (2) Contact fatigue wear The friction pair of chain wheel and chain is alternating contact stress, and fatigue pitting is easy to form on its friction surface.The index of metal contact fatigue strength is contact fatigue limit, that is, the maximum stress without pitting corrosion under a certain number of stress cycles.Contact fatigue limit of 40Cr after surface quenching treatmentσ0h = hrc17 + 200σ0H=1016MPa。According to the stress distribution diagram, the maximum stress value of sprocket chain socket is 884.4 MPa.The value is close to the allowable contact fatigue limit of sprocket surface, and it is easy to cause pitting failure at the maximum stress.However, due to the poor lubrication condition of chain wheel and chain, pitting corrosion has not been formed in time, which has caused wear. At this time, the main damage form is wear rather than pitting corrosion.Contact fatigue wear is the main form of sprocket wear, which basically determines the service life of sprocket. (3) Abrasive wear Due to the inevitable contact between the chain and pulverized coal, there is a little pulverized coal on it, which is brought to the contact of sprocket chain socket. The pulverized coal contains a little sharp hard sand, which will cause the surface material of sprocket to fall off during friction, which is abrasive wear.Abrasive wear is related to the hardness of friction material and abrasive.From the influence diagram of abrasive hardness on wear, it can be seen that when the hardness of abrasive is close to the hardness of friction material, high-speed wear of friction material is caused, because coal powder is mixed with a little sharp hard sand, which is also one of the main reasons to accelerate the wear of sprocket wheel.
