Diagnostics of processes of wear of materials of ball-tube mills

Changes in material hardness of balls, which are used as the working body of ball-tube mills was investigated. Both new balls and balls with different operation time were examined. Hardness of not only the surface layer, but also over the entire depth was studied. These measurements were carried out to find the wear-out areas. It was found that areas with a reduced hardness, where ball material destruction occurs, are formed on the surface during operation. To determine the changes in the material properties, an ultimate strength was tested. Its values in different parts of the ball with the time change were found. It was revealed that the discontinuity surface structure is the same for all areas and the entire time interval. This indicates the absence of phase transitions of ball materials during operation. Diagnostics of the surface structure by the electron beam was conducted. This work allows to forecast the destruction rate of balls during their use and identify priorities for improving their performance.