scope:

Chrome-molybdenum steels are in common use in pressure vessels for high temperature and high pressure hydrogen applications. The proper alloy is usually determined from the Nelson Curves. The 21/4Cr-1 Mo steel has found particular favor in services such as hydrodesulfurization. For 2l/4 Cr-1 Mo, the mode of damage expected is surface decarburization-not the more far reaching hydrogen attack. A more detailed confirmation of all the effects of temperature and hydrogen pressure was thought useful. To carry out such studies, Task Group I of the Japan Pressure Vessel Research Council Subcommittee on Hydrogen Embrittlement conducted a joint research program on 2l/4 Cr-1 Mo Steel assessing the effects of exposure time, temperature, and hydrogen pressure on deterioration of properties. This report presents the results as determined by changes in mechanical properties and microstructure of base material and simulated heat affected zones. The report was first presented at the First International Conference on Current Solutions to Hydrogen Problems in Steel, ASM, Nov. 1982