APPLYING A MULTI METHOD APPROACH TO CHLORIDE INDUCED SCC OF TWO AUSTENITIC CR-NI-MO-N STAINLESS STEELS

摘要

There is a large number of investigation methods in chloride induced stress corrosion cracking (CISCC) research. In many papers only a very limited number of testing methods is applied. The goal of the present paper is to show results of several testing methods on one specific corrosion system. Constant load tests (CLT) at different polarization conditions, slow strain rate tests (SSRT) at different strain rates, scanning electron microscopy (SEM) and field emission scanning electron microscopy (FE-SEM) for fracture surface characterization, energy filtered transmission electron microscopy (EFTEM) combined with energy dispersive x-ray analysis (EDX) for near crack tip investigations and x-ray photoelectron spectroscopy (XPS) for passive layer characterization were used and discussed to give an idea about the behavior of austenitic CrNiMoN stainless steels in hot and highly chloride containing environments. Results favour a slip dissolution mechanism without a pronounced effect of hydrogen and show an alloying dependent CISCC crack growth rate.