Prevention of Corrosion Fatigue

Prevention of corrosion fatigue. One or a combination of the following procedures is recommended to prevent corrosion fatigue ... 

Such inhibitors act by forming protective films on the surface of the metal being subjected to corrosion fatigue. The selection of a right inhibitor and its effective concentration is important for prevention of corrosion fatigue. The price is very expensive as large amounts of inhibitors are required. 

For prevention of corrosion fatigue observe precautions and preventive measures as follows ... 

Piping systems should be designed to be cleaned on-stream, if possible and necessary. Critical parts or parts of systems subject to heavy corrosion should be separately dismantleable. Blind or non-inspectable areas should be kept to a minimum in a fail-safe design and, where unavoidable, additional strength must be provided to prevent the critical effects of corrosion fatigue. 

Corrosion fatigue, therefore, is a special case of stress-corrosion cracking and fatigue failure. Figure 4-451 shows an example of pipe failures due to corrosion fatigue. Corrosion fatigue can be prevented or reduced by ... 

Effect on corrosion fatigue The combination of corrosion and fatigue can cause rapid failure, and a coating of nickel, by preventing corrosion, can increase the life of the parts. Figure 13.10 shows results obtained by the National Physical Laboratory on mild steel Wohler specimens sprayed with... 

Mechanical effects Corrosion can often be initiated or intensified by the conjoint action of mechanical factors. Typical examples include the presence of inherent or applied stresses, fatigue, fretting or cavitation effects. Inhibitors that are effective in the absence of some or all of these phenomena may not be so in their presence. In fact it may not always be possible to use inhibitors successfully in these situations and other methods of corrosion prevention will be required. 

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