scope:

The regulations governing the design of pressure vessels are based on experience gained over many operational years and have evolved, primarily, to prevent failure under static load conditions. This design philosophy has been successful in ensuring adequate service behavior because pressure vessels are not usually subjected to large numbers of load fluctuations during their expected service life. However, the need to effectively utilize materials and to provide the utmost in safety and reliability has made it imperative to determine the fatigue behavior of these structures. The fatigue life of structural components is determined by the initiation of cracks and their propagation to critical dimensions. This report presents fatigue-crack-initiation and fatigue-crack-propagation data for pressure-vessel steels operating in a benign environment and at temperatures below the creep region. Data obtained by testing pressure vessels and pressure vessel components, and the results of surveys of pressure vessel failures are discussed. It is concluded that the probability of fatigue failure of properly designed and fabricated pressure vessels is very low and that the most effective approach to keep this probability low is to minimize the magnitude of the stress (strain) concentration factors. This can be accomplished through proper design of details and through proper fabrication