The Comparison of Energizer between the Rubber Wood Ash and CaCO3in the Pack Carburizing Process with Rubber Wood Charcoal Powder

Abstract

The purpose of this research is to apply a pack carburizing process for low carbon steel hardening with rubber wood charcoal to improve the mechanical properties of low carbon steel grade AISI 1020. The depth hardness of low carbon steels hardening was compared with those of non-hardened low carbon steel. The experiment was made by pack carburized low carbon steel at 950°C with the carburizing time of 30, 60 and 90 min and cooled in air. It was heated by austenitizing treatment at the temperature of 850°C for 30 min and quenched in water. The specimens were tempered at a temperature of 150°C for 30 minutes. The carburizing substance is rubber charcoal mixed with 10% of energizer such as rubber wood ash and CaCO₃. The specimens were checked for case depth by Micro-Vicker testing and microstructure inspection. The results showed that the rubber wood charcoal mixed with CaCO₃ energizer at 950°C with the carburizing time of 90 min produced the highest hardness value of 681 HMV and the surface hardness of rubber wood ash was 665 HMV. It was also found that the microstructure on the surface with both CaCO₃ and rubber wood ash were martensite and cementite. For this reason, rubber wood charcoal ash can be used as an energizer to pack carburizing as well.