1967 Volume 36 Issue 8 Pages 840-845
In the previous reports, we investigated the initiation of stress corrosion cracking in austenitic stainless steels by the boiling solution of 42 percent MgCl2 from the electrochemical standpoint. As the result of this research, we confirmed that the stress corrosion crack never occurs, unless the potential of test piece rises above the certain value determined by applied stress and material.
In this report, we discussed whether the above conception with crack initiation potential obtained in the boiling solution of 42 percent MgCl2 is applicable to the case of stress corrosion cracking in the solution of different temperatures, concentrations or pH.
When the temperature of solution was changed within the range of our experiment (from 120°C to 154°C), the induction period of stress corrosion cracking became long with a decrease of temperature of 42 percent MgCl2 solution. But the potential of test piece was constant in every case, when the stress corrosion crack occurred.
On the other hand, when the concentration of MgCl2 boiling solution was changed within the range of our experiment (from 26.2 percent to 42.0 percent), the weaker the concentration, the longer the induction period was. But the potential for initiation of crack was constant.
Moreover, when the pH of solution was changed, the potential was always constant at the time of crack initiation.
Judging from the result obtained in this paper, it became clear that the necessary value of potential for the initiation of crack did not change at all with the variation of temperature, concentration and pH of MgCl2 solution.
