Studies on the effect of Cold Plastic Deformation and Heat Treatment on the Microstructural Arrangement and Corrosion Behaviour of Mild Steel in Acidic Media

Abstract

Mild steel is the most extensively used carbon steel for numerous industrial applications, where it is exposed to various service environments containing acids, bases and salt solutions. From industrial point of view, plastic deformation and heat treatment are among the essential manufacturing steps in mild steel processing and these steps can implicate its corrosion behaviour. This work investigated the effect of cold plastic deformation and subsequent high temperature heat treatment on the microstructure and corrosion behaviour of mild steel in two different concentrations (0.5M and 1.0M) of sulphuric acid (H2SO4), using the weight loss method. Mild steel samples were cold pressed to thickness reduction of 20%, 40% and 50% and subsequently heat treated at 700oC and 900°C and then air-cooled. The test duration lasted for 25 days and the weight loss measurements were taken at intervals of 5 days. It was observed that corrosion rates of the samples were generally higher in the 1.0M than in 0.5M acid solution. The as-received and heat-treated mild steel samples exhibited higher corrosion rates than the cold-pressed and heat-treated samples. The results indicated strongly that cold working accompanied by heat treatment improves corrosion resistance of mild steel in acidic media.