Pitting is more critical in components with which thickness?

• A. Very thick sections
• B. Very thin sections
• C. Moderate thickness
• D. Variable thickness

Answer: (B)

Pitting is a localized form of corrosion that creates deep, narrow holes in the material. The danger lies in how much wall is left after a pit forms. In very thin components, even a relatively small pit can eat up a large fraction of the wall thickness, possibly penetrating completely and causing leaks or failure with little warning. In thicker sections, the same pit depth leaves more material still intact, so the component can tolerate the damage longer without immediate through-wall failure. So pitting is most critical when the thickness is very thin, because the margin for safety is smallest and failure can occur quickly.