Corrosion Protection Claddings and Weld Overlays
Some pressure vessels are provided with corrosion-resistant claddings or weld overlays to protect the vessel shell in severely corrosive process environments, when a reasonable corrosion allowance would not be sufficient for high corrosion rates. High-alloy materials, such as austenitic stainless steel or Monel, are usually used for these linings. Deterioration of the protective cladding or weld overlay during service could expose the vessel shell to severe corrosion attack.
Visual examination (VT) is usually sufficient to determine the integrity of the cladding or weld overlay on a pressure vessel shell. Dye-penetrant (PT) examination can supplement VT to determine if cracks are developing in the lining, and hammer testing can indicate if the lining has separated from the vessel shell.
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