Evaluation of Nigeria’s Local Fluids as Industrial Quenchants for the Heat Treatment of Tool

The study examined the impact of quenching heat treatment on the mechanical, physical and microstructural properties of AISI 8250 Alloy Steel using vegetable oils as quenchants. Palm oil, Groundnut oil and Shea butter were compared to water-quenched and the annealed sample used as control. Heat treatment was run up to 850oC austinitic temperature and fast-cooled in these quenching media before tensile, hardness and metallographic analyses were carried out. The Ultimate Tensile Strength (UTS) of the samples were increased when quenched in Water, Palm oil, Ground nut oil and Shea butter by 69.01, 57.75, 42.25 and 38.73% respectively. Also, the surface and core hardness of the samples increased in the order of Water>Palm oil>Groundnut oil>Shea butter, while the surface to core hardness gradients of 85.29, 81.25, 90 and 100% was recorded for Water, Palm oil, Groundnut oil and Shea butter respectively. The results suggest that water quenching may only be recommended due to its very high strength and hardness potentials provided a post-quenching heat treatment such as tempering will be used to improve its adverse effect of cracking tendencies. However, Palm oil was the best quenchant when a good balance between mechanical strength, hardness and crack resistance was desired in addition to its sustainability and environmental friendliness. Study has shown Palm oil’s additional value apart from its food demands and its potency as a favorable replacement for water in quenching heat treatment in any industrial, commercial and domestic processing of materials.