Corrosion testing continued specimen requirements

Predictions of the corrosion performance should be obtained from published data and through testing.The essential requirements of accelerated testing are that the acceleration should produce the same mode of failure and reflect at least a known order of resistance of some alloys in service media.168 The most common approaches employed to achieve testing objectives in SCC are the use of high stresses, slow continuous straining, precracked specimens, higher concentration of species in the test environment than in the service environment, increased temperature, and electrochemical stimulation.169 For electrochemical corrosion, the properties of the medium at the interface should be considered in accelerated tests. 

Metal coatings are intended in most cases as corrosion protection barriers. In accelerated tests, the time required for corrosion should be reduced preferably by exposing the specimens continuously to conditions, which in service would arise only intermittently. At the same time, the conditions used should cause no damage of types other than that which would arise under conditions of natural exposure. 

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