抄録
The softening caused by long-term aging for 10Cr-1.5Mo-VNbN steel was investigated with hardness test at temperature range of 500 to 650°C up to 105 hours. The softening caused by creep was also investigated at temperature range of 600 to 650°C under stress of 98 to 294 MPa. The change in hardness during long-term aging was able to be expressed by a simple curve in plotting against Larson-Miller parameter. The Softening was accelerated by the stress larger than 79 MPa. The change in hardness during creep under the stress of σ (MPa) was correlated with those of long-term aging by plotting against the parameter of logT+log(20+logt)+0.000239(σ-79)
where T is the test temperature (K) and t is the loading time or aging time (h).
A method to detect the creep damage and to estimate the residual life was deduced from the above mentioned results.
