Behavioural Corrosion Mechanism of Hot Worked Mild Carbon Steel Immersed in various Acidic Environments

Abstract

Heat treatment of metals is an important operation in the final fabrication process of many engineering components. Hot working help to improve the mechanical properties of the affected metals. In this research work, behavioural corrosion mechanism of hot worked mild steel carbon immersed in various acidic environments were evaluated mainly to determine the weight loss and corrosion rate of the material. In evaluating the corrosion rate of the mild steel in acidic environment, weight loss approach was adopted. The coupons were measured prior to immersion and different weight measurements were taken at interval of 24 hours, over the period of 168 hours. The difference in weight between the original weight and the final weight at each 24 hour interval (weight loss), was estimated and used for the calculation of the corrosion rates. The results obtained reveal an increased in weight loss as concentration of acids increases and this resulted to increase in corrosion rate as experienced by coupons immersed in five samples of acid environment used in this research work. Besides, nitric acid proved to be more aggressive, and this was followed by hydrochloric acid, tetraoxosulphate (VI) acid, phosphoric acid, and acetic acid was the least. Therefore, if acid must be used with mild steel, nitric acid should not be used.