Development of technology for production of grinding bodies with improved performance properties from the rail steels rejection

Abstract

In order to develop optimal modes of production of grinding balls at screw rolling mills from the rejection of rail steel blanks that were not previously used for the production of this type of product, experimental studies of the influence of the chemical composition of rail steels and the temperature conditions of their rolling on the quality of the structure and impact resistance of the balls were conducted. Based on laboratory studies, it was determined that alloying with chromium and nickel, as well as increasing the carbon content, leads to a deterioration in the microstructure of the resulting balls, without increasing their hardness. It is optimal to produce grinding balls made of 76XF and 76F steel grades. Experimental studies carried out in laboratory and industrial conditions determined the optimal rolling temperature of the balls, which provides a reduction in cracking and an increase in the performance characteristics of grinding media. It is shown that an increase in the heating temperature of the rail steel billets for rolling and the temperature of the beginning of rolling of the balls from 980 °C to 1030 °C causes an increase in the quality of the structure of the balls and an increase in their impact resistance while maintaining a high surface hardness. The expected economic effect of the introduction of modes of production of grinding balls from the rejection of rail steels, developed taking into account the above recommendations on the optimal chemical composition of the initial blanks and the temperature conditions of their rolling, is 22.5 million rubles / year. The work was carried out using the equipment of SSIU of the Center for Collective Use “Materials Science” of the Siberian State Industrial University.