Chapter 14: Stress-Assisted Corrosion and Cracking

This chapter discusses two damage mechanisms in which stress plays a major role. In the one case, stress causes cracks in the oxide scale on metals, leading to preferential corrosion attack. An example from industry of this type of failure is the circumferential cracking that occurs on the waterwall tubes of supercritical coal-fired boilers fired under low NOx combustion conditions, conducive to the production of sulfidizing environments. In the other case, stress contributes to brittle fracture in the form of intergranular cracking. The phenomenon, which is known by various names, typically occurs at the lower end of the intermediate temperature range and has been observed in ferritic steels, stainless steels, Fe-Ni-Cr alloys, and nickel-base alloys, as described in the chapter.