The Effect of Quenching Media on the Hardness of AISI 1045 Steel

Abstract

Steels, as one of the main components of construction requires great strength. Steel can be modified its strength by adjusting the percentage of the amount of its constituent substance composition. Some substances that can be used as a composition in steel include: Iron (Fe), Carbon (C), Phosphorus (P), Manganese (Mn), Sulfur (S), Chrome (Cr), and so on. In addition, according to its use, steel can also be mixed with other substances to form alloy steel. However, most steels are only dominated by a mixture of iron (Fe) and carbon (C) called carbon steel. In its initial condition, in carbon steel, a mixture of Fe and C will form ferrite as the main component of steel. The ferrite contained in the steel will make the steel more ductile, but its hardness value is minimal. In some cases, sometimes steel with a higher hardness value will be needed, with the same percentage of content. For this reason, an effort is needed to increase the hardness value of steel. Efforts to increase the value of this steel hardness can be done by treating the steel with heat treatment. One method of this heat treatment is by quenching. This is done by heating the steel to a temperature of 850C, and then rapidly reducing the temperature. With an increase in temperature, the crystal structure of the steel will deform to a ferlite structure. The ferlite structure will deform again slowly into ferrite as the temperature decreases. However, if the temperature is lowered rapidly, the steel structure will deform to martensite instead of unformed ferrite. The martensite phase is harder than ferrite. This research examines the quenching process using several cooling media on AISI 1045 steel. The cooling media used are: Circulated air, water, lubricating oil, and liquid smoke.