Performance assessment of vegetable oil and mineral oil blends during heat treatment of medium carbon steel

Cooling effect of palm kernel oil and mineral oil (SAE 40) with their blends as quenching media for heat treatment of medium carbon steel was investigated. Palm kernel oil was blended with SAE 40 in the ratio of 1 : 3, 1 : 1 and 3 : 1. Medium carbon steel probe of diameter 12.5 mm and 60 mm height was used to determine the cooling intensities of the oils and their blends. Mechanical properties and microstructure of the quenched steel samples were determined. Quench severity of pure palm kernel oil was found to be greater than that of SAE 40. The blend consisting of 75% palm kernel oil and 25% mineral oil showed higher cooling power as compared to other blends. Samples quenched in 100% palm kernel oil showed higher hardness values than the blends whereas samples quenched in 100% mineral oil (SAE 40) showed the least hardness value.