PENGARUH VARIASI PENDINGINAN TERHADAP BAJA S45C PADA UJI MIKROSTRUKTUR DAN KEKERASAN DENGAN MEDIA OLI SAE20 DAN AIR

Quenching is one of the heat treatments that is often used in the industrial world, especially in the manufacturing industry. This is because the quenching process can improve the mechanical properties of the material, especially violence. However, the material that has been given a quenching process will make the material brittle because research is needed on the factors that affect the agility of the quenching process itself. Important factors of the quenching process itself are one of them regarding cooling media and cooling rate. This study aims to determine the effect of oil and water viscosity on the mechanical properties of S45C steel which has been carried out by heat treatment and quenching processes. the heating process uses a heating furnace, while the cooling process uses SAE 20 water and oil. Research shows that the difference in lubricant viscosity in the cooling process can affect the value of material hardness. The lower the viscosity of the lubricant, the hardness value tends to increase, while the higher the viscosity of the lubricant, the hardness value tends to decrease. Cooling the process changes to hard material, which is characterized by the results during the hardness testing process shows an increase in the value of hardness, this is due to changes in the microstructure of ferrite and pearlite structure into a hard and, brittle, martensite structure.