Pengaruh Variasi Heat Treatment Terhadap Kekerasan Pada Material Rotor Bar Ripple Mill

Abstract

Ripple mill functions as a separator of palm kernels and shells by breaking the nuts. The ripple mill itself consists of a rotating rotor bar on a stationary ripple plate. One of the problems that occurs with the ripple mill is the material failure in the form of deformation on the rotor bar, which causes the ripple mill machine to no longer be able to break the nuts into kernels. To address this issue, heat treatment is required for the rotor bar. The hope is that the heat treatment process will improve the material properties, specifically increasing the hardness of the rotor bar. The method used involves variations of heat treatment: normalizing at a temperature of 860 °C with a holding time of 50 minutes and air cooling, hardening at a temperature of 860 °C with a holding time of 50 minutes and water cooling, and tempering at a temperature of 600 °C with a holding time of 30 minutes and air cooling. After applying all of these heat treatment variations to the specimens, Vickers hardness testing is performed according to ASTM E92. From this research, it can be concluded that in the raw material specimen, the highest hardness is at point 2 with a hardness value of 236.6 HV. The normalizing heat treatment at point 1 resulted in an average hardness value of 208 HV. The hardening heat treatment at point 4 resulted in an average hardness value of 382.9 HV. The tempering heat treatment at point 1 resulted in an average hardness value of 279.9 HV.