INVESTIGATING THE EFFECT OF SOME LOCAL VEGETABLE OILS AS QUENCHING MEDIA ON MECHANICAL AND METALLURGICAL PROPERTIES OF NST 60-2 STRUCTURAL STEEL

M. ALAGBE

Department of Metallurgical Engineering

Institute of Technology Kwara State Polytechnic Ilorin, Nigeria.

E-mail: alagbemic@yahoo.com

ABSTRACT: The hardening characteristics of NST60 – 2 structural (medium carbon) steel quenched in palm Kernel oil, groundnut oil, palm oil, Shea butter oil, air and water were investigated and evaluated.  This study was conducted on the possibility of improving it wear performance. The investigation was carried out in two parts; the effect of some quenching media on microstructured steel. A micro-structural examination of the quenched specimens was undertaken to ascertain the efficiency of some quenchants on the surface hardening. The results obtained indicate that all the quenching media responded well to all surface hardening with palm kernel oil giving the highest hardness value, being more efficient than groundnut oil, palm oil and shea butter oil.  The Shea butter oil gives the least hardness because; it has higher viscosity which lowers the cooling rate and consequently the lesser the possibility of martensite formation. In general excellent hardening properties were obtained with these vegetable local oils. It is established that surface hardening of NST 60-2 structural steel using palm kernel oil, groundnut oil, palm oil and shea butter oil can be adopted as a heat treatment process for improving its wear performance at less cost.