The study on mechanical properties of pack carburized low carbon steel using BaCO3 as energizer

Abstract

Machine components such as crankshaft and gear require hard surface and ductile core characteristics. One method to obtained such characteristics is pack carburizing. This research concern to compare the mechanical properties of carburized low carbon steel under different carburizers; GBC (80% goat bone charcoal + 20% BaCO3) and BC (80% bamboo charcoal + 20% BaCO3) and derived from reference. Pack carburizing was carried out by heating up to a temperature of 950°C, holding for 4 hours and quenching in the oil. The results showed that hardness, yield strength, tensile strength and modulus elasticity of carburized steels increased significantly, however, there was a decrease in elongation. The closer to the core the lower of hardness obtained until reach a total case depth of 1.5 mm and 2 mm for carburized using BC and GBC, respectively. The use of carburizer GBC produces carburized steel with a higher yield strength (51.75 kg.mm-2), tensile strength (74.58 kg.mm-2), and elongation (5.78 %) than carburizer BC but lower in hardness (558.13 HV1), modulus elasticity (256.79 GPa), and effective case depth (0.33 mm). The mechanical properties of carburized low carbon steels have fulfilled requirements as the material of gear or shaft.