What Does Stress Corrosion Cracking (SCC) Mean?
Stress corrosion cracking (SCC) is a progressive fracturing that occurs in metals as a result of the combined influence of tensile stress and a corrosive environment.
Structural failure due to SCC can be very unpredictable—failure could occur after as little as a few hours of exposure, or the equipment could continue to function normally for months or even years. Metal components frequently experience SCC, and virtually all alloy systems are susceptible to SCC by specific corrodents under specific conditions.
Corrosionpedia Explains Stress Corrosion Cracking (SCC)
The mechanism of stress corrosion cracking is not well understood but it is believed to be caused by stress, corrosive environments and susceptible microstructures. In some cases crack initiation has been associated with the formation of a brittle film at the surface of the material, which could have lower ductility due to a different metal composition than the bulk material.
SCC can be controlled in numerous ways, including:
- Selecting a material that is not susceptibleto SCC
- Controlling stresses through careful design and minimizing stress
- Keeping concentrations below the critical value
- Reducing stresses through heat treatments
- Using corrosion inhibitors during cleaning operations
- Coating the material and effectively isolating the material from the environment