The importance of pitting depends on the thickness of the metal; pitting may be serious in which sections and less important in which?

• A. Thick sections
• B. Large sections
• C. Small sections
• D. Thin, Thick sections

Answer: (D)

Pitting is a localized form of corrosion that removes metal in small, deep spots rather than thinning the metal evenly. The seriousness of pitting hinges on how much material remains to carry load. In thin sections, a pit can eat through a substantial portion of the thickness or reach through the section, rapidly compromising strength and potentially leading to failure under service loads. In thick sections, pits may grow without immediately threatening structural integrity because there is more remaining cross-section to sustain the loads, so the issue is less critical initially. That’s why pitting may be serious in thin sections and less important in thick sections.