scope:

OBJECTIVE

ASME Standards Technology, LLC has sponsored a thorough review of current allowable stress values in ASME Boiler and Pressure Vessel Code, Section III, Division I, Subsection NH, and to identify inconsistencies and potential limitations on the use of some current values in Subsection NH for austenitic stainless steel. More specifically, long term creep tests on AISI Type 304H and 316H stainless steel (SS), completed after the current allowable stress values were established, identified some heats whose rupture life fell below currently published allowable values, particularly above 1200ºF (650ºC). Since some of these errors and limitations could impact near term design activities for Gen IV applications, there is an urgent need to address this issue.