PENGARUH VARIASI WAKTU TAHAN (HOLDING TIME) PADA PROSES CARBURIZING TERHADAP KEKERASAN PERMUKAAN DAN KETAHANAN AUS BAJA KONSTRUKSI UMUM

General Construction Steel is a material that is widely used in the machining field because of its tough, soft and easy to machining properties. Many engineering techniques are used to improve the mechanical properties of steel to obtain the required material, such as increasing the hardness and wear resistance by adding carbon or carburizing. The carburizing process is carried out at 900 oC with a holding time of 1 hour, 2 hours, and 3 hours and then a cooling process is carried out using air with wood charcoal as a source of activated carbon and calcium carbonate as a catalyst. From the results of the carburizing process it is known that the highest surface hardness value is 103.14 kg / mm2 with a holding time of 3 hours and the lowest surface hardness of 80.2 kg / mm2 with a holding time of 1 hour. The highest wear resistance is obtained with a holding time of 3 hours with specific wear of 3.17 mm3 / Nm and the lowest wear resistance is obtained with a holding time of 1 hour with a specific wear of 4.37 mm3 / Nm. From the results of carburizing with a holding time of 1 hour, 2 hours, and 3 hours gave an increase in surface hardness to the raw material by 44%, 55%, and 86% followed by an increase in wear resistance of 23.8%, 28.5%, and 44.7%