Martensitic stainless steels, which are used for different industrial applications are well known for their outstanding mechanical properties and their good corrosion and wear resistance. In the studies related to the mentioned properties, special attention is paid to the formed precipitates, which should be studied in terms of their hydrogen trapping behaviour. However, there is limited understanding about their hydrogen trapping behaviour. As part of this study, the hydrogen trapping behaviour of martensitic stainless steels and the
different trap sites in the material are investigated, especially the role of secondary hardening precipitates, that are formed during tempering - astrap sites. The material issubjected to various heat treatments and subsequently the effects of the microstructure on the trapping behaviour are examined by using thermal desorption spectroscopy. Size, proportion and distribution of the
precipitates affect their hydrogen trapping behaviour. A high number of finely distributed precipitates in the material acting as hydrogen traps, will affect the hydrogen embrittlement behaviour of the investigated alloy. Furthermore, hydrogen mapping and high-resolution microstructural characterizations are conducted to gain an in-depth view on hydrogen trapping of the microstructure in this material class.