Vegetable oils as quenchants for hardening medium carbon steel

Abstract

Groundnut (Arachia hypoge) oil and palm (Elaeis guineeness) kernel oil were investigated as vegetable quench-ing media for carbon steel (0.45 % C) by determining the characteristic temperature-time cooling curves and rel-ated mechanical properties. The three stages of cooling examined during quenching were vapour blanket, boili-ng and convection. The study was conducted to find vegetable oil alternatives to the commonly used synthetic polymer quenchants, which are considered hazardous, costly and not readily available. The influence of cooling rates of the quenching media on microstructure, tensile strength, yield stress and hardness of medium carbon steel were also investigated. The mechanical properties of groundnut oil quenched steel were higher than palm oil quenched steel, but the wear resistance measured by hardness testing was higher when quenched in palm kernel oil than in groundnut oil.