There is no fixed boundary for distinguishing between low- and high-temperature corrosion. Most commonly, it is assumed that low-temperature corrosion processes occur in the presence of liquid water at temperatures up to a maximum of about 200°C (392°F). However, some authors extend this upper limit to 260°C (500°F). For the purpose of this library, we excluded environmental cracking phenomena from the category of low-temperature corrosion. However, it’s important to note that many cracking damages require the presence of an electrolyte (such as water) and/or occur at temperatures below 200°C-260°C.
Corrosion damages that occur above 200-260°C (392-500°F) are commonly classified as high-temperature corrosion mechanisms. High-temperature corrosion reactions typically involve direct interaction with oxygen (oxidation), molecular hydrogen (HT Hydrogen Attack), or species such as sulfur (sulfidation, high-temperature H2-H2S corrosion).
Environmental assisted cracking (EAC) occurs due to a combination of three primary factors; the type of material, the applied mechanical stress, and the corrosive environment. EAC encompasses various mechanisms, including stress corrosion cracking (SCC), hydrogen embrittlement (HE), and corrosion fatigue (CF), among others.
These types of failures originate from the mechanical properties of metallic materials, which are linked to their specific crystal structure, grain sizes, and types of dedicated phases formed, among other factors. Parameters such as hardness, yield strength, and ductility tend to change based on process variables like elevated temperature, duration of exposure, and the presence of a corrosive environment. Consequently, the mechanical properties of metals gradually deteriorate over time, leading to failures. Predicting or quantitatively measuring these types of failures is challenging due to the multidimensional correlations between various parameters and the specific structure of metallic crystals.
