Abstract
An index of the susceptibility to stress corrosion cracking (SCC), ISCC of solution-annealed type-304 stainless steel (SS) was measured in a simulated concentrated brine in which the 10 mg/L of cupric, cuprous, nickel and zinc ion (Cu2+, Cu+, Ni2+, Zn2+) were dissolved, in order to evaluate the effect of a minute quantity of metal ions in concentrated chloride solutions on the SCC of SS. The index for the simulated concentrated brine to which the 10％ O2-Ar and the pure-O2 were exposed was also measured. ISCC was inversely proportional to the molality in the electrochemical equivalent of the copper ions, as well as the dissolved oxygen in the test solution, regardless of the kinds of these chemical species; ISCC decreased with on increase in SCC susceptibility. ISCC decreased with the addition of minute quantities of Ni2+ and Zn2+ when they were done singly. However, in the case where Ni2+ or Zn2+ was simultaneously added with Cu2+, ISCC was lower than that for the solution to which the same concentration of Cu2+ was solely added.
