Finite element calculation of crack propagation in Type 304 stainless steel in diluted sulphuric acid solution under stress corrosion conditions

Stress corrosion cracking is a synergetic interaction between a stresses material and its environment. A physico-electrochemical simulation tool based on Finite Element (FE) method has been developed to describe such an interaction by incorporation of the mass-transport and the chemical reactions in environment, the electrochemical reactions at the metal surface and the mechano-corrosive interaction at the crack tip. Type 304 stainless steel in dilute sulphuric acid solution system is chosen to simulate the SCC effect in constructive elements in BWR conditions. The effect of the dissolved oxygen concentration, the sulphur content, the temperature, the stress intensity, the crack's length, the fluid flow, sensitization and yield strength were analyzed and compared with experimental observations when it is possible. The FE simulation of one particular case is time-consuming process and requires additional efforts to implement changes in the system in FE framework. To make easy for the final user the parametric study of SS304/H2SO4 system the results of many precalculated case are summarized in the data base and an interpolation procedure developed to predict the crack growth rate for an arbitrary set of the system parameters.