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The influence of parameters of a thermo-mechanical rolling process on corrosion properties of materials 316L and Alloy 825 was studied by means of the DL-EPR-method and a conventional corrosion test. Prior to polarization measurements, optimization of the DL-EPR-method was conducted. SEM was used to characterize microstructure and type of attack before and after corrosion testing. A strong correlation between annual corrosion rates and DL-EPR-test results was obtained. Due to the low tendency of both alloys to form corrosion-promoting precipitates, the applicable range of process parameters for both alloys is large and the fabrication process in general is not critical.

Nickel-based alloy 625 was investigated by means of a conventional corrosion test (Streicher-test according to ASTM G28A [1]) and an electrochemical potentiokinetic reactivation test (according to ASTM G108 [1], with some modifications). Susceptibility to intergranular corrosion after various heat treatments was examined by using both test methods and the results were compared. Dependent on the type of heat treatment applied, both methods showed partially different results. Possibilities and limitations of replacing Streicher-test with EPR-test are pointed out and commentated. In conclusion, the EPR-test presents itself as a promising and quick investigation technique for detecting susceptibility to intergranular corrosion in nickel-based alloys.