在低于400°F的温度下，钢中百万分之几的氢的有害影响早已被认识到。此类效应的常见经验包括延性降低和断裂强度降低。最近，当钢暴露在氢环境中时，已经有了一些加速亚临界裂纹扩展的认识。所有这些影响对于高压氢气压力容器的应用，以及暴露在能够向钢中充氢的腐蚀性介质中的容器都很重要。从材料性能的角度来看，随着硬度或强度水平的增加，更容易发生损伤。 因此，氢损伤问题在高强度钢的应用中尤为重要，高强度钢对压力容器具有最有利的强度重量比。 尽管人们普遍认识到氢的有害影响，但许多变量的重要性尚未定量确定，无法直接应用于压力容器的设计或使用。只有在一般情况下，才知道缺口或其他应力升高因素的影响。研究项目的主要目标应是提供有关机械性能和环境因素限值的定量信息，以确保在能够向容器钢提供氢气的环境中防止低应力失效。 对报告中审查的文献和经验的解释表明，高强度钢的主要失效模式是一种相对脆性的准解理断裂，它是由微裂纹扩展引起的，并且这种模式也可能扩展到低强度钢的领域。研究的目的应该是建立从准解理断裂行为转变为韧性断裂行为的强度水平、氢含量或有效氢压力和温度的限制条件。

The detrimental effects of a few parts per million of hydrogen in steel at temperatures below about 400°F have long been recognized. Common experience of such effects include reduction of ductility and reduction of fracture strength. More recently there has been added some realization of accelerated subcritical crack propagation when steel is exposed to hydrogen environments. All these effects are important to the application of pressure vessels for high-pressure hydrogen, and for vessels exposed to corrosive media capable of charging steels with hydrogen. From the materials properties standpoint, damage is much more apt to occur as the hardness or the strength level increases. Thus, the problem of damage by hydrogen is particularly important in the application of higher strength steels, which have the most favorable strength-to-weight ratio for pressure vessels. Although the detrimental effects of hydrogen are generally recognized, the significance of many of the variables has not been quantitatively established in terms that allow direct application to pressure vessel design or use. Only in a general way are the effect of notches or other stress raisers known. The primary objectives of research programs should be to furnish quantitative information on limiting values for mechanical properties and environmental factors so as to insure against low stress failures in environments capable of supplying hydrogen to the vessel steel. The interpretation of the literature and experiences examined in the report suggests that the predominant mode of failure in the higher strength steels is a relatively brittle, quasi-cleavage fracture which results from propagation of microcracks, and that this mode may extend into the realm of the lower strength steels also. Research should be aimed toward establishing limiting conditions with respect to strength levels, hydrogen content or effective hydrogen pressure, and temperature for the change over from this quasi-cleavage fracture behavior to one of ductile rupture.