Stress Corrosion Cracking at ASTM A36 Plate with Varied Grain Orientation

Abstract

Stress corrosion cracking (SCC) has been acknowledged as a trigger phenomenon which can cause a failure especially in welded pipeline installations. By the name, three factors must be involved in SCC failure: stress, corrosive environment and an initial crack. This article observes the effect of grain orientation to the SCC failure in ASTM A36 plate. The results show that with lower grain orientation the precracked plate withstands longer in a certain corrosive surroundings and stress load. From microstructure observation the finer grains in lower orientation are believed to increase the SCC resilience. The microstructure at fracture region shows that the lower orientation tends to develop intergranular crack growth whilst at higher orientation transgranular is exhibited. This phenomenon also explains why the lower grain orientation can hold SCC failure longer.