| 摘要 |
PURPOSE:To decide a life consumption rate of a metal component, by a method wherein a relation of a creeping life with deterioration in hardness and temperature is found beforehand. CONSTITUTION:A stress of 8-30kg/cm<2> is applied at a chrome molybdenum vanadium steel as a sample at various temperature ranging from 500 to 600 deg.C. A relation between hardness and a Larson-Miller parameter during various types of the tests is shown in a drawing, In the drawing, T is an absolute temperature, t is a time, phic is ratio of a holding time under a temparature stress condition showning a time fraction to a creeping breaking time. The drawing is shown in an equal creeping life curve, and a relation among phic, Vickers hardness, the absolute temperature, and the time can be found from the drawing. The relation are stored in a computer, and hardness obtained at a given periodical test, a time during which a metal is used, and a temperature are inputted. This computes a creeping life. |
