Stainless steel stress corrosion cracking is a general term for the mutual failure of stressed alloys due to crack propagation in a corrosive environment. Stress corrosion cracking has a brittle fracture morphology, but it can also occur in highly ductile materials. The necessary conditions for stress corrosion cracking to occur are the presence of tensile stress (whether residual stress or applied stress, or both) and the presence of a specific corrosive medium.
The formation and propagation of cracks are approximately perpendicular to the direction of tensile stress. The stress value that causes stress corrosion cracking is much smaller than the stress value required to fracture the material in the absence of corrosive media. Microscopically, the cracks that pass through the grains are called transgranular cracks, and the cracks that expand along the grain boundaries are called intergranular cracks.
If the stress reaches its breaking stress in air), the material breaks as a normal crack (in ductile materials, usually by the aggregation of microscopic defects). Therefore, the cross-section of a part that fails due to stress corrosion cracking will contain characteristic areas of stress corrosion cracking and areas of "dimples" associated with the aggregation of microdefects.
