WEAR BEHAVIOR OF STEPPED AUSTEMPERED DUCTILE IRON BALLS IN GRINDING IRON ORE

Jayaraj B.Siddan

Abstract: In the present study, an attempt has been made to evaluate the suitability of austempered ductile iron as grinding media material for grinding the iron ore in a ball mill. They are austenitised at 920 0 C for 60 minutes and given stepped austempering heat treatment: 400 0C for 15, 30, 45, and 60 minutes followed by 300 0C for 120 minutes for each case. Grinding wear behaviour of these materials are assessed for wear loss in wet condition. The grinding operation are carried out for 60 minutes at 60 % pulp density under closed mill conditions .The pH of mineral slurry is varied from 7 to 10.5 pH to assess the influence of pH on grinding wear behavior of ball material. It is found that wear rate of grinding media material increases proportionally with decrease in pH. These wear rate values are compared with En-31 forged steel under similar conditions. It is found that wear resistance of stepped austempered ductile iron is superior compared to En-31 forged steel balls for wet condition.

Keywords: Austemper ductile iron, wear, grinding, ball mill

DOI: https://doi.org/10.15623/ijret.2014.0315091