Internal Friction Peaks in the High Chromium and High Chromium-Nickel Steels at Elevated Temperatures

摘要

Several internal friction peaks were observed in four grades of high chromium steels and eight grades of high chromium-nickel steels in the measurement at elevated temperatures by means of a low-frequency torsional pendulum. In three ferritic high chromium steels (27Cr, 25CrTi and 20Cr) quenched from an elevated temperature, an internal friction peak was observed in the vicinity of 570C. The activation energy associated with this internal friction peak for the specimens of 27Cr and 20Cr was found to be about 87,000 cal/mole. In the specimens of the above-mentioned three high chromium steels, which were furnace-cooled from an elevated temperature, an additional friction peak appeared in the vicinity of 640C. In the specimens of the 13Cr grade, which were furnacecooled from an elevated temperature, an internal friction peak was observed in the vicinity of 610C. In all eight austenitic high chromium-nickel steels an internal friction peak was observed in the neighborhood of 730C. The activation energy associated with this internal friction peak, determined in the 18Cr 18Ni specimens, was about 85,000 cal/mole. The origins of these friction peaks were discussed on the basis of the preliminary experimental results. (Author)