Abstract :
Nodular cast iron is iron with almost the same level of ductility and is
equivalent to steel, nodular cast iron is generally widely used as crankshafts, steel
pipes, cylinder heads and gears. To obtain good mechanical properties, a qenching
process can be carried out including using water, sea water and coolant as a
variety of cooling media. The purpose of the quenching process is to increase the
hardness of the metal and produce a microstructure on the metal.
This research was conducted to determine the effect of variations in cooling
media on the quenching process on the hardness and microstructure of nodular
cast iron FCD-45. This research was given heat treatment with a heating
temperature of 950°C and holding time 30 minutes then cooled rapidly with
variations Cooling media in the form of water, sea water, and coolant.
FCD-45 nodular cast iron test results obtained the lowest hardness value on
raw material 52.05 HRC The highest hardness was obtained on coolant cooling
media with a hardness of 85.87 HRC, whereas with water cooling media obtained
a hardness of 77.51 HRC and with water media the sea gets a hardness of 84.99
HRC.