Learn about the forms of metal corrosion

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The forms of metal corrosion can be divided into two main categories: general (uniform) corrosion and local corrosion. The former occurs more evenly across the entire surface, while the latter occurs only locally. Examples include pitting corrosion, crevice corrosion, intergranular corrosion, stress corrosion cracking, corrosion fatigue, hydrogen-induced cracking, selective corrosion, wear corrosion, delamination corrosion, etc. (Figure-1). Generally, local corrosion is far more harmful than general corrosion, and some forms of local corrosion can be sudden and catastrophic. Accidents such as fires, explosions, and environmental pollution can occur if equipment and pipes perforate or break, resulting in the leakage of flammable, explosive, or toxic fluids. According to some statistical data, local corrosion accounts for about 70% of the corrosion of chemical processing equipment. Although uniform corrosion poses a low level of risk, a large amount of metal is exposed to the gases and water that cause it, resulting in extremely significant economic losses.