Stress corrosion is associated with the simultaneous presence of corrosion and tension stress. In most cases it becomes apparent only at temperatures above 50-60ºC. Tension stresses can be:
- internal (residual stresses) or
- external (mechanical load, differential thermal expansion etc.)
A stress relieving heat treatment is the most usual method of reducing internal stresses. Since this type of corrosion is initiated by local corrosion attack, an appropriate choice of the steel grade to be used is essential.
- The duplex stainless steels with a ferro-austenitic structure (DMV 22.5; DMV 25.7; etc.) are a lot less sensitive to stress corrosion and often represent an economical solution.
- Very high nickel grades (DMV 928; DMV 825; DMV 600; DMV 625 etc...) are necessary to be applied in severe corrosive environments.
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