Abstract
Temperature-accelerated creep rupture tests were performed by using miniature specimens of 2.25Cr-1Mo steel and 18Cr-8Ni steel, and an iso-stress method was examined to predict the long term creep rupture time by extrapolation from short time data. The results obtained are as follows.
(1) For 2.25Cr-1Mo steel, the accuracy of remaining life prediction in the long duration side becomes better by correcting it on the basis of rupture ductility.
(2) For 18Cr-8Ni steel, the remaining life in the long duration side can be predicted accurately, when the change of microstructure does not influence creep rupture life.
(3) When the above method was applied to an actual boiler, an accurate life assessment was possible. This method is confirmed to be effective.
