Utilization of Coconut Shell in Pack Carburizing Process of ST37 to the Rate of Wear at the Different Cryogenic Treatment

摘要

Coconut shell waste so far has been widely used as mainly only as traditional fuel. To increase the economic value of the coconut shell, it can be processed into activated carbon. In this study activated carbon was used as a carburizing pack material to increase the wear resistance of ST37 steel. The carburizing pack process is carried out by heating to austenite temperature(γ) with temperature variations of 800°C, 850°C and 900°C with carburizing time for 1, 2 and 3 hours, then cooling by quenching in water. The development of methods to improve wear resistance of materials is carried out with an advanced process namely cryogenic treatment. Cryogenic processes were carried out by immersing the specimen in liquid nitrogen(temperature ± -195°C) for 2 hours, 24 hours and 48 hours. Furthermore, wear testing is done using a rotary disc with a load of 10kg for 3 minutes. In general, based on test results, it appears that there is a decrease in the wear rate of ST37 steel which has undergone a carburizing pack process without a cryogenic process, from the raw material wear rate of 0,0003499685 g/m down to 0,0001166562 g/m to 0,0000272198 g/m or decreased wear rates ranging from 66% to 92%. While the specimens that received additional cryogenic treatment the wear rate decreased from 0.0000777708 g/m to 0.0000194427 g/m or decreased in the wear rate ranged from 78% to 94%. The lowest wear rate occurred in specimens with carburizing treatment at 900°C for 2 and 3 hours, with cryogenic treatment for 48 hours. This shows that the carburizing pack process followed by the cryogenic process can reduce the wear rate of ST37 low carbon steel or it can be said to significantly increase its wear resistance.