VDA 238-200 (11/2020)
VDA 238-200: Prüfung der Empfindlichkeit höchstfester Flacherzeugnisse aus Stahl gegenüber wasserstoffinduzierter Rissbildung - Allgemeiner Leitfaden / Testing of the susceptibility of advanced high strength steel sheets to hydrogen induced cracking - general guidance (Version 11/2020) - Gruppenlizenz (group license), AGB (GTC) Art. 10, 2
Components made of high-strength steel can show brittle failure due to the effect of hydrogen. This often occurs with a time delay and without warning.
In terms of metal physics, hydrogen-induced cracking or hydrogen embrittlement is defined as a material damage induced by atomic hydrogen present in or diffused into the metal lattice. This effect is known either as hydrogen-induced stress corrosion cracking (HISCC, german HISRK) or delayed hydrogen-induced cracking (or delayed fracture).
Material damage caused by hydrogen can only occur if the following boundary conditions are simultaneously fulfilled, see Figure 1:
- A material with sufficient strength and critical microctructure,
- a sufficient supply of diffusible hydrogen, e.g. from corrosion processes or acidic media, and
- a critical stress state, e.g. high constant tensile stresses at the magnitude of the material yield stress.