Stress Corrosion Cracking Behavior of Duplex Stainless Steel by Slow Strain Rate Tests

Stress corrosion cracking (SCC) behavior of three duplex stainless steels with a low nickel composition was studied. The results are compared with two commercial duplex steels of standard composition, one of them containing molybdenum. The slow strain rate tests were carried out in solution containing 50 g/L of chlorides and under a controlled potential of 300 mV vs. saturated calomel electrode (SCE), with the purpose to reproduce one aggressive condition. The study has allowed finding important differences between several materials. From the three duplex stainless steels with low nickel content, that with the higher nitrogen content presents embrittlement induced by SCC. The results demonstrate that with an appropriate alloying it is possible to reduce the nickel content by 50% and to maintain the resistance to the SCC in highly aggressive media.