Master external pressure charts
- Hartford Steam Boiler Inspection and Insurance Co., CT (United States). Codes and Standards Dept.
This paper presents a method to develop master external pressure charts from which individual external pressure charts for each material specification may be derived. The master external charts can represent a grouping of materials with similar chemical composition, similar stress-strain curves but produced to different strength levels. External pressure charts are used by various Sections of the ASME Boiler and Pressure Vessel and Piping Codes to design various components such as cylinders, sphered, formed heads, tubes, piping, rings and other components, subjected to external pressure or axial compression loads. These charts are pseudo stress-strain curves for groups of materials with similar stress-strain shapes. The traditional approach was originally developed in the 1940`s and is a graphical approach where slopes to the strain curves are drawn graphically from which pseudo-strain levels are calculated. The new method presented in this paper develops mathematical relationships for the material stress-strain curves and the external pressure charts. The method has the ability to calculate stress-strain curves from existing external pressure charts. The relationships are a function of temperature, the modulus of elasticity, yield strength, and two empirical material constants. In this approach, conservative assumptions used to assign materials to lower bound external pressure charts can be removed. This increases the buckling strength capability of many materials in the Code, providing economic benefits while maintaining the margin of safety specified by the Code criteria. The method can also reduce the number of material charts needed in the Code and provides for the capability to extend the existing pressure charts to higher design temperatures. The new method is shown to contain a number of improvements over the traditional approach and is presently under consideration by appropriate ASME Code committees.
- OSTI ID:
- 404242
- Report Number(s):
- CONF-960706-; ISBN 0-7918-1786-5; TRN: IM9652%%102
- Resource Relation:
- Conference: American Society of Mechanical Engineers (ASME) pressure vessels and piping conference, Montreal (Canada), 21-26 Jul 1996; Other Information: PBD: 1996; Related Information: Is Part Of Pressure vessels and piping codes and standards: Volume 2. PVP-Volume 339; Esselman, T.C. [ed.] [Altran Corp., Boston, MA (United States)]; Balkey, K. [ed.] [Westinghouse Electric Corp., Pittsburgh, PA (United States)]; Chao, K.K.N. [ed.] [Consumers Power Co., Jackson, MI (United States)]; Gosselin, S. [ed.] [Electric Power Research Institute, Charlotte, NC (United States)]; Hollinger, G. [ed.] [Babcock and Wilcox, Barberton, OH (United States)]; Lubin, B.T. [ed.] [ABB Combustion Engineering, Windsor, CT (United States)]; Mohktarain, K. [ed.] [CB and I Technical Services, Plainfield, IL (United States)]; O`Donnell, W. [ed.] [O`Donnell Consulting Engineers, Inc., Pittsburgh, PA (United States)]; Rao, K.R. [ed.] [Entergy Operations, Inc, Jackson, MI (United States)]; PB: 225 p.
- Country of Publication:
- United States
- Language:
- English
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