Technique for Studying the Kinetics of Intergranular Crack Nucleation on AISI Type 304 Stainless Steel in Oxygenated Water at 289 C Available to Purchase

The design of a system with which to study the kinetics of intergranular crack nucleation on Type 304 stainless steel in water containing 100 ppm O₂ at 289 C (554 F) is described. A bellows loading system capable of holding samples in simple uniaxial tension is discussed, and the results of constant load experiments on sensitized Type 304 stainless steel are presented. The elongation-time behavior of the above material is characterized by a distinct "stair-step" type of curve which is taken to indicate the presence of a mechanical event in the cracking mechanism. The nucleation or induction time, T_n, is shown to increase markedly as the applied stress was decreased from 30 to 20 kpsi. Cathodic protection inhibits crack initiation indefinitely, thereby indicating the presence of an electrochemical event in the cracking mechanism. Crack nuclei are shown to be associated with regions of plastic deformation, and can in certain instances initiate and propagate transgranularly down carbide decorated slip traces.