Effect of manganese, silicon and chromium additions on microstructure and wear characteristics of grey cast iron for sugar industries applications

•A modified cast iron is composed of 3.3% C, 2.1% Si, 3% Mn, and 2.1% Cr for shells.•The modified cast iron has higher tensile strength and hardness.•The modified cast iron shows less wear than the last used cast iron.

Mill roller shells are amongst the most important manufacturing-line elements in the sugar production process. They are carefully designed according to many surface criteria amongst which wear resistance is the most important. To increase the life of the mill roller shells, the resistance of the surface to failure by abrasion should be increased. In this investigation, a series of sixty-six cast iron samples with varied contents of chromium, manganese and silicon were prepared. The microstructure and the mechanical properties were studied. Hence, the wear of all the specimens was evaluated using the pin-on-disc test, with a high-speed steel disc. The accumulated weight loss was measured and the wear rates were determined at constant normal test load of 20 N and constant pin velocity of 1.28 m/s during the pin-on-disc test. The accumulated weight loss was measured as a function of the number of revolutions. From test results, it was found that the wear rate, for all conditions under investigation, decreases with the increase of manganese and chromium additions at constant silicon additions. The wear rate obtained for the samples containing 3% manganese and 2.02% silicon was equal to 1.2267 mg/s, and the minimum wear rate was obtained for the samples containing 3% manganese, 2.11% silicon, and 2.11% chromium (equal to 0.3400 mg/s). The enhancement in the wear resistance of the chromium alloyed samples was attributed to the increase in the chromium carbides volume fraction.