Designing Components Made of High Strength Steel to Resist Stress Corrosion Cracking Through the Application of Controlled Sh

Author:  M.D.Shafer
Source:  The Shot Peener magazine, Vol 09/Issue 4, Winter 1995
Doc ID:  1995046
Year of Publication:  1995
Abstract:  
ABSTRACT Stress corrosion cracking (SCC) is material fatigue associated with the combined presence of stress and corrosive environment. The events leading to catastrophic failure usually begin with the mechanical rupture of the material's protective oxide coating. These microscopic ruptures grow into pits and propagate into the substrate material, whereupon due to surface tensile stresses, crack propagation begins, which is further exacerbated by chemical attack at the crack tip. SCC is an insidious enemy to aerospace, boiler and naval engineers. Amazingly, a component designed for infinite life in an inert atmosphere, may last only a few months or several hours in a corrosive environment. Several methods exist which prevent SCC or delay initial crack propagation. The application of shot peening imparts compressive stress to the exposed subsurface layers of the material, which delays crack initiation and slows crack propagation in the compressive zone. In conjunction with proper material selection and component synthesis, shot peening allows the possibility of manufacturing and assembling SCC resistant parts. KEYWORDS: corrosion, high carbon steel, intergranular fracture, nickel alloy, residual compressive stress, shot peening, stainless steel, stress corrosion cracking, transgranular fracture.