Corrosion behaviour of mild steel in diverse environments: a comparative study of hot-rolled and cold-rolled specimens

Abstract Materials undergo degradation and structural failure due to corrosion, leading to substantial economic losses in industrial applications. This study investigates the corrosion behavior and mechanical degradation of hot-rolled and cold-rolled mild steel in six different environments (air, tap water, seawater, NaCl, HCl, and H₂SO₄) over a period of 30 days. The analysis included weight loss, corrosion rate, thickness reduction, and mechanical strength evaluations at multiple intervals. Results revealed that cold-rolled specimens suffered up to a 55% loss in elongation and a 40% decline in tensile strength, particularly in acidic conditions. The superior performance of hot-rolled steel highlights the influence of manufacturing methods on corrosion resistance. Among all tested environments, sulfuric acid proved to be the most aggressive, with cold-rolled steel specimens exhibiting 10.212 mm and 5.649 mm of corrosion compared to 9.488 mm and 5.577 mm for hot-rolled steel specimens during the 30-day exposure period. Sulfuric acid exposure caused a maximum thickness reduction of 38.12%, along with a 40% loss in tensile strength and a 55% reduction in elongation at break for cold-rolled steel. Under the same exposure conditions, the compressive strength of hot-rolled specimens decreased by 25%. This comparative study offers valuable insights for designing durable steel structures and developing advanced corrosion mitigation strategies.