Abstract
The aim of this research was to study the effect of Nickel additions to high strength steel alloys and to obtain an optimal chemical composition that does not compromise the tensile strength and wear resistance properties provided by the OEM (Original equipment manufacturer) with cost saving to the manufacturing local foundry. The nickel content was added in composition from 0.5 wt.% to 3.5wt% to the molten metal.
Each cast alloy with different composition of nickel was cast with green sand system and a keel block was produced. The test bar was then cut from the keel block and sectioned for laboratory analysis for determining tensile strength properties (ultimate tensile strength. yield strength and % elongation), Brinell hardness test, Impact test, microstructural evaluation both optical and scanning electron microscope and wear resistance.
The results obtained shows that there is significant increase in tensile strength and wear resistance and slight decrease in toughness with increase in nickel additions. The phase analysis and microstructural evaluations of each alloy after heat treatment showed a pronounced difference on the microstructure of each alloy produced.
The study shows a significant improvement on wear resistance of alloy with increasing nickel content. However, the best optimal chemical composition was observed to be 2.0% nickel alloy for optimal cost to fulfil the OEM mechanical and wear properties for the high strength steel used for mining grounding application, so this meant a 22.7% cost saving when compared to the current chemical composition used in the foundry.