Hot hydrogen attack (HHA) is a form of degradation caused by carbides reacting in steel, thereby forming methane (CH4). The probability of HHA damage in industrial plants is dependent on its partial hydrogen pressure and operating temperature. In the worst cases, HHA may lead to damage, which can have catastrophic results for people and the environment. Since even a minor failure could cause unacceptable downtime and a substantial loss of money, conducting regular hot hydrogen attack inspections is indispensable for detecting failures and discontinuities at the earliest stage possible.

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