Effect of Bath Temperature on the Cooling Rate of Sesame Seed (Sesamum indicum) Oil
Authors: Gaminana JO, Dodo MR, Abubakar BA
The effect of temperature on sesame oil (Sesamum indicum oil) as a quenching medium for medium carbon steel was investigated. Samples were cut and machined for mechanical properties test and cooling curve determination prior to hardening operation. Sesame oil was measured at different volumes such that the final temperature rise of the quenching bath after quenching would be 26 oC, 51 oC, 66 oC, and 81 oC. The samples were normalized, and then austenitized at 850 oC. They were then soaked for 40 minutes and then quenched in sesame oil (4.88 dm3, 1.91 dm3, 1.18 dm3 and 0.84 dm3), water, and SAE40 engine oil. Half of the samples quenched were further tempered at 350 oC and held for 40 minutes and then air-cooled. Cooling curves for all the quenching media used were developed. Specific heat capacities of the various media used were determined. Hardness and impact strength of the samples was tested. The test result obtained from the quenched samples shows that the highest hardness value (48 HRC) and impact strength (570 kJ/m2) was obtained from the samples quenched in sesame oil maintained at a temperature rise of 26 and 80 oC respectively. Microstructures of the various samples were analyzed using optical microscopy (OM), in all the samples; Martensite, retained austenite and fine pearlite structure were observed. The research shows that sesame oil maintained at a temperature rise of 80 oC gives the good combination of impact strength and hardness value. Thus, it is recommended to be used as a quenching medium for medium carbon steel.
Affiliations: Department of Metallurgical and Materials Engineering, Ahmadu Bello University, Zaria, Nigeria.
Keywords: Martensite, Quenching, Sesame Oil, Cooling Curves, Medium Carbon Steels, Specific Heat Capacity
Published date: 2019/12/30