Mechanical Properties Improvement Evaluation of Medium Carbon Steels Quenched in Different Media

Abstract

The effect of quenching on the mechanical properties of medium carbon steels using coconut (CW) water, pap water (PW) and spent engine oil (SPE) which have been largely considered as wastes was investigated. All specimens were normalized at a temperature of 840 in order to remove residual stresses induced during machining operations. Various specimens were heated to ranges of 730-790 and soaked for the range of 30-60 minutes respectively. Brinnel hardness tester was used to obtain the hardness values while Testometric M500-50AT model machine was used for the tensile test of the specimens. The highest hardness value (609.97 BHN) was obtained from the specimen heated to 790 quenched in pap water as compared with 166.4 BHN for the normalized as-received sample. The yield (YS) and ultimate tensile (UTS) strengths of the quenched specimens were better than the normalized as-received sample. SPE-quenched samples yielded the highest YS and UTS combined. The hardness value increased while YS and UTS decreased with soaking time for different temperatures. The highest hardness value for the specimens was obtained from coconut and pap water. Rather than been considered as wastes, coconut water, pap water and spent engine oil can improve the mechanical properties of medium carbon steel when used as quenching media.