The formation of cracks in a corrosive environment is what stress corrosion defects are all about. This can result in the unwarranted failure of supple metals when subjected to considerable tensile stress, such as higher temperature levels.
Stress corrosion cracking is considered highly specific to certain chemicals present in the specific alloys. The chemical makeup present in these alloys is only mildly corrosive. So, what happens is that metal parts with major SCC may look shiny and bright, but are actually already filled up with the cracks. This is the reason the condition can go about undetected, until it actually fails.
Identifying the Causes
According to mearsintegrity.com, stress corrosion cracking happens due to three factors: the susceptibility of the material, constant exposure to a corrosive environment and presence of tensile strength above the threshold. Control of any of the above can prevent the occurrence of SCC.
Selecting and Controlling the Material
The first step against stress corrosion cracking is to choose the right type of material to be used during the design and construction phases. Carefully selecting metals not known to be prone to SCC and making it is fabricated properly can prevent or minimize the occurrence of stress corrosion cracking in the future.
Implementing Stress Control
As mentioned, one of the primary factors that can lead to stress corrosion cracks is the occurrence of stress beyond the given tensile strength of the material. To prevent it, control or reduce its presence below its given threshold. While this may not always be feasible, given that the material is there to provide support for stress, it may be possible to reduce residual stress that occurs during the construction and welding process. Residual stress can be eliminated through stress annealing and is particularly useful in carbon steel products.
Understanding Environmental Control
Probably the most direct method of preventing SCC is to control the immediate environment. If the active component is present in the environment where people have control over, then it may be possible to remove it to prevent SCC from occurring.