604 Behavior of hydrogen in SCM435 steel

The SCM435 steels are being used for a high-pressure hydrogen tank for the hydrogen-station of Japan Hydrogen and Fuel Cell Demonstration Project. In general, high-strength steels are prone to cause hydrogen embrittlement. The cause of the embrittlement and behavior of hydrogen in the steel has not been clarified yet. Hydrogen microprint technique(HMPT) is an effective method to investigate the hydrogen behavior. In the present study, the behavior of hydrogen in two SCM435 steels with different strength has been investigated by means of HMPT. As a result, it has been confirmed that cathodic electrolytic charging causes hydrogen invasion and that hydrogen is discharged from the steels during holding after charging.