CORROSION ENVIRONMENT SCC CRACK DEVELOPING PREDICTION METHOD

摘要

PROBLEM TO BE SOLVED: To predict the development of a stress corrosion crack (SCC) by calculating the crack developing speed based on the crack tip stress expansion coefficient in the specific equation indicating the relation between the crack tip strain speed of the SCC in the stationary progress state and the stress expansion coefficient. SOLUTION: When an SCC crack reaches the critical crack forming time to grow into a developing crack, a critical SCC crack is formed. When the stress expansion coefficient of the critical SCC crack is the SCC lower limit stress expansion coefficient or above, the stationary progress of the SCC crack occurs. The crack progress speed da/dt and the crack progress quantity are calculated in sequence with the equation indicating the relation between the crack tip strain speed dct /dt and the stress expansion coefficient in an S-curve starting from the SCC lower limit stress expansion coefficient, where (n) is the active dissolution parameter, is the filtered water conductivity, ECP is the corrosion potential, and EPR is the effective electrochemical reactivation factor. The progress of the SCC crack can be predicted.