Stress and High Temperature-Related Corrosion

In addition to the many different forms of boiler section ferrous corrosion already described, several other less common types occasionally develop. In particular, corrosion processes may evolve that are interrelated with stress, deposition, and/or high temperatures (thermal effect corrosion), and together these may lead to metal fatigue (metal fatigue corrosion), metal failure, and even more serious problems such as the risk of a boiler explosion. 

Residual stress generally from the effects of metal rolling, bending, or welding operations 

Applied stress as a result of flame impingement or uneven heating 

Cyclic stress developing from on-off and peak-load boiler operations 

Stress corrosion cracking (SCC) or embrittlement corrosion describes any of a number of corrosion processes where in a corrosive environment, localized stress accelerates the rate of corrosion that may occur under or within a deposit. 

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Table 7.7 Summary notes stress and high temperature related corrosion.

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