The analysis of carbon carburizing of ST 60 steel with 80 mesh due to hardness and microstructure

Abstract

ST 60 steel is a steel with a medium carbon content of about 0.56% by weight. The process will affect the amount of carbon that will be diffused on the surface when the carburizing process is carried out. Different types of carbon from materials and finer carbon grains, it is hoped that carbon diffusion will easily occur.  In this study, carbon grains were made with a mesh size of 80, from variations of coal, coconut shell carbon, mangrove tree carbon to microstructure and hardness in ST60 steel material. The method carried out is to heat the ST 60 steel which is inserted in a pack of carbon powder until 900 °C is held for 60 minutes.  After that, room temperature cooling is carried out so that carbon atoms are still diffused until the temperature is completed. The tests carried out microstructure (SEM) on raw materials formed pearlite and ferrite phases, after pack carburizing the phase formed pearlite, ferrite and coated by graphite from carbon atoms caused the hardness of the specimen to increase in the pearlite phase exposed to carbon. The results of the Rockwell Hardness test on raw material 52.3 HRA after the pack carburizing process, the hardness of the material has increased which is found in coal carbon of 62.2 HRA, coconut shell carbon of 64.8 HRA and mangrove carbon of 60.7 HRA from the test. The chemical composition of the results obtained in the raw material condition of 0.404 when in pack carburizing increased each material’s coal carbon by 0.829, coconut shell carbon by 0.88, mangrove carbon by 0.76. The largest intake of carbon when pack carburizing compared to the largest is in the pack carburizing with coconut shell charcoal.