Creep Rupture of Internally Pressurized Cylinders at Elevated Temperatures

抄録

In this paper the results of experiments on the creep and creep rupture of internally pressurized cylinders of a low carbon steel and a 2 1/4 Cr-1Mo steel are reported. Theoretical analysis of the stress distribution of thick-walled cylinders during creep was derived on the basis of a nonsteadystate multiaxial stress creep theory as well as a finite strain theory. These results were checked by comparing with the experimentally determined stress distributions which were derived from the measurement of residual stress in the cylinders which have crept by means of the Sachs and X-ray method of stress analysis, and a fairly good agreement was obtained between the two. In addition, a discussion was made on the stress criterion for creep rupture of pressurized tubes in consideration of the effects of stress increase due to creep deformation, hydrostatic component of stress, wall thickness, maximum principal stress and anisotropy of the material. It was concluded that the so-called mean diameter formula is valid for the design formula of boiler and pressure vessels irrespective of materials and testing conditions.