The Influence of Hardening Heat Treatment on The Corrosion and Microstructural Morphology of Aisi 1044 Steel in Acidic Admixture Environment

This study investigates how hardening heat treatment affects corrosion and microstructural morphology in AISI 1044 steel in an acidic admixture environment. The samples were machined to 40 mm in length. Some samples underwent heat treatment and were homogenized at 950 oC and held for 1 hour 30 minutes, and subsequently quenched in water, while the remaining samples were left untreated to serve as controls. Corrosion rates for both the heat-treated and the control samples were evaluated using the Gravimetric Method (GM), and their microstructural morphology was examined using Optical Metallography Microscopy (OMM) in alignment with standard procedures. The corrosion results obtained revealed that the quench-hardening heat treatment resulted in better corrosion resistance, with the hardened steel samples having corrosion rates between 0.0751 mm/yr to 0.0542 mm/yr compared to the control samples with corrosion rates between 0.112 mm/yr to 0.0777mm/yr, with a peak corrosion on the 40th day of 0.135 mm/yr. The results also indicate that the control and heat-treated samples experienced a progressive increase in percentage reduction in corrosion rate, with peak values of 0.5% and 2.9%. The microstructure results obtained showed that the quenched-hardened steel samples have better corrosion resistance compared to the control samples, owing to the formation of martensite laths in the matrix of the heat-treated samples. Thus, the investigation showed that hardened heat treatment is suitable for the production of agricultural implements to be used in an acidic chloride environment.