Extrapolation of stress rupture data on 9 to 12% Cr steels
The stress rupture strengths at times of up to 300 000h have been evaluated. In relation to the stress rupture strength, data from four steels, namely 9Cr1Mo, 9Cr2MoNbV, 9Cr1MoVNb and 12CrMoV, were examined and in each case four different parameters (Larson-Miller, Orr-Sherby-Dorn (original), Orr-Sherby-Dorn (ORNL) and Manson-Haferd) were employed to extrapolate the data out to 300,000h. At temperatures relevant to steam generators (about 500 C) there was found to be little difference in predicted long-term strength values using the four approaches. However, the lower 95% confidence limits have been evaluated and it was found that for some of the steels these were different from the often assumed minimum set at 80% of the average. The rupture ductility values have been statistically evaluated at specific temperatures to establish the trend in ductility with increasing rupture time.
Bibliographic Reference: EUR 12388 EN (1989) 108 pp., FS, ECU 10
Record Number: 199010008 / Last updated on: 1994-12-01
Original language: en
Available languages: en