CORROSION RESISTANCE

The importance of steel cannot be over-emphasized, especially in the field of agricultural planting, harvesting and processing. Medium-carbon steel being more prevalent in use for tool steel and machine parts was adopted for this study. This research was aimed at investigating the mechanical properties (hardness and impact strength) as well as wear and corrosion resistance of medium carbon steel for producing agricultural farm implements, thus, microstructure analysis was also carried out for further investigation. The medium carbon steel as received was prepared in line with every ASTM standard procedure through sizing, cutting and cleaning before heat treatment. During hardening, the prepared specimens were heated in an electric furnace for a soaking time of one hour, thirty minutes, and then quenched with water for approximately 30 minutes. Afterwards, samples were then used exclusively for the hardness, impact strength, wearing resistance and corrosion resistance in line with ASTM specification. After conducting the hardness test, an approximate hardness for the treated material is 2092.4 N/mm2 as compared to the “as-received” value that was 1307.6 N/mm2 ; thereby indicating a significant increase in the hardness of the material. Impact test conducted gave an approximated result of 14.7 J; thereby depicting the energy absorption capability of this medium carbon steel alloy. Wear rate of approximately 25 % was reduced for the hardened medium carbon steel in comparison to the untreated steel. After testing for corrosion resistance of the steel in a corrosive acidic chloride environment, results obtained showed that the heat treatment process enhanced corrosion resistance of the medium carbon steel samples in the medium. The micrographs obtained showed that the grain boundaries of this material were xiii greatly attacked by this environment. The corrosion product at these grain boundaries were suspected to be precipitates of metallic inclusion.