The Influence of Particle Size and Soaking Time on Surface Hardness of Carburized AISI 1018 Steel

This work examines the effect of process variables on the mechanical property of carburized AISI 1018 steel quenched in water and oil for improved performance. A carburizer consisting of charcoal was used for research with sea shell as energizer. Samples were carburized using weight percent of seashell (10, 20, 30 and 40%) with particle sizes of 212 µm, 425 µm and 600 µm respectively. The process was carried out at carburizing temperature of 950°C, soaked for 4, 6, and 8 hours and quenched in oil and water. The samples were further tempered at 200°C for 1hour to relieve the stress built up during quenching. Hardness test was carried on the steel samples. The results of the study showed that hardness values of the carburized and tempered steel increased with influence of soaking time, volume fraction and particle sizes of energizer. The optimal carburizing effect was achieved at 90% charcoal and 10% seashell (energizer) of 212 µm particle size at 8 hrs soaking time when quenched in water.