A Study of Processing Parameters on the Carburization of C2R Steels

Abstract

This study reports an investigation of the effect of carburizing variables - temperature, time and percentage of energizer on the case properties of C2R steel obtained from HMT Ltd. India. A carburizer consisting of hardwood charcoal and coke respectively in the ratio of 2:1 was used for the research with sodium carbonate as the energizer. The carburizing box was filled with 20mm thick carburizer compound prior to fixing the steel samples in place. The specimens were carburized using different percentages of energizers (10, 20 and 30%) at different temperatures (820, 860, 900 and 940°C) for different times (from one to five hours). All the specimens were quenched from carburizing temperature, ground to polished surfaces and then etched for ten minutes in 25% Nital. The case depth was measured using the calibrated ocular of an inverted metallurgical microscope fixed at 100 x magnification. The hardness values of the C2R steel cases were measured with a micro hardness tester that uses diamond pyramid indenter. The results of the study showed that the average hardness of the C2R steel cases increased with temperature for any given carburizing time and temperature. For a given percentage energizer and temperature, the case depths and hardness increased with time. Increase in the percentage energizer however decreased the activation energy required for diffusion to occur exponentially.