Assessment of Remaining Life of Fossil Power Plant Parts by means of a Miniature Creep Rupture Test

Abstract

In order to validate a procedure for creep rupture tests using miniature specimens, a sampling technique and a method of making the miniature specimens were investigated. Finally, the use of the iso-stress creep rupture test on the miniature specimens to predict the remaining creep life of Cr-Mo-V, 2¼Cr-Mo and 1¼-½Mo steel was examined. The creep curve, rupture life and ductility of the miniature specimens tested in argon were similar to those of conventional sized specimens in air. The fracture mode of the miniature specimens was also consistent with that of conventional sized specimens. On a graph showing tremperature T vs. log time to rupture tr, the creep rupture data were represented with an iso-stress line, respectively. Each iso-stress line shifted parallel with the stress level. Moreover, the sampling device that was developed was applied to the operating plant components. Samples have been successfully removed from it and were obtained without affecting the material properties around the core hole. © 1990, The Iron and Steel Institute of Japan. All rights reserved.