Abstract
Effect of sensitization heat treatment at 973K on the probability distribution of failure times of stress corrosion cracking of Type 304 stainless steel in boiling magnesium chloride solution at 399K, 411K and 427K and mainly at the stress of 100MPa has been examined. In all conditions examined, total failure time Tf is found to be divided into crack initiation time Ti and propagation time Tp, their distribution obeying a three parameter Weibull distribution with the high correlation coefficient of 0.941-0.996. Effect of sensitization heat treatment is observed only at 399K, at which Tp determines Tf. The shape parameter m of the distribution shows a maximum value for the highest sensitization heat teratment condition at 2.00×103s, at which intergranular cracking is observed in a part of fractured surface. From the comparison of fracture mode with the shape of the discribution, a mixed type distribution is also suggested to be fitted instead of a single three parameter Weibull distribution.
