Official Answer
Answer
Pitting corrosion is dangerous because it creates localized 'micro-notches' that significantly reduce the fatigue endurance limit. In a hydraulic cylinder, the ring is under constant tension or compression. A pit can quickly transition into a fatigue crack due to the high-stress intensity at the base of the pit. For subsea hydraulics, 316 Stainless Steel is the minimum requirement, but for high-pressure systems, Inconel 718 is often used because its high Nickel and Chromium content prevents pit initiation even in stagnant seawater trapped in the groove.
