Characterization of AISI 1020 steel carburized with variation of mass ratio between charcoal from Nypa fruticans shell and CaCO3 from chicken egg shell, in association with its mechanical properties

Abstract

AISI 1020 low-carbon steel is carburized with regular method. Carbon source is charcoal of Nypa fruticans shell and energizer is calcium carbonate (CaCO3) from chicken (Gallus gallus domesticus) egg shell. Variation in this research is the mass ratio between the charcoal and the energizer, which are 90:10, 80:20, and 70:30 for weight ratio of charcoal and energizer, accordingly. The result of carburization observed in this research are hardness and toughness, coupled with surface microstructure observation and carbon diffusion depth. Impact test result shows that there is small increase of toughness value as the ratio of energizer in carburizing mixture is increased. The highest value of toughness is 24,25 MPa, obtained from 7:3 sample, 12% higher than lowest toughness value of carburized sample, from 9:1 specimen. Stagnation is observed on the result of hardness test, where the results revolves around 78 HRA. This hardness value is 64.4% higher than non-carburized sample.