In this study, a pack carburizing process was carried out on low carbon steel using activated carbon, coconut shell charcoal and various catalysts in the form of ale-ale shells, eggshells, and beef bones. The method used is heating at an austenite temperature of 900 oC with a variation of holding time of 30, 60, and 90 minutes, then quenching using water, followed by hardness testing with the Vickers method and composition testing. The general result is that the three types of catalysts can accelerate the diffusion-reaction so that the carbon addition process occurs and the longer holding time can provide an opportunity for the carbon formed to transform from the pearlite microstructure to the austenite microstructure, and when quenching it forms the Martensite microstructure. Of the three types of catalysts that produced the highest hardness was an ale-ale shell, from the initial hardness 119 HV to 464 HV.

To increase the hardness and wear resistance of low carbon steels (low carbon steel), it is usually done by a hardening process, namely by adding carbon elements. One of these processes is by using the Pack carburizing method. In this study, the pack carburizing process will be carried out on low carbon steel St 37 using activated charcoal media from ironwood combined with ale-ale shells catalyst with a composition of 10%, 20%, 30% 40% and 50%. Furthermore, composition testing and hardness testing were carried out using the Vickers method. The results of this study in the composition test, there was an addition of carbon due to diffusion and an increase in the maximum hardness of the catalyst composition by 30% with a hardness of 572.6 VHN.