Hydrogen Induced Delayed Failure Flashcards
What is hydrogen induced delayed failure?
when steel contains dissolved hydrogen or exposed to hydrogen environment and subjected to sustained load, it has a decreased fracture stress
Where does fracture initiation occur?
in the region of highly localized stress where hydrogen is concentrated due to its diffusion in triaxially stressed locations
What is the best way to detect failure?
sustained loading, as impact tests may not detect the embrittlement
What parameters affect delayed hydrogen failure?
> strength of steel: as strength ^, failure susceptibility ^
stress is required for failure
decrease in chemical potential of hydrogen atoms decreases susceptibility
GB impurity segregation gives trapping sites for hydrogen
inclusions give places for cracks to initiate
