| Temper embrittlement is the third high-temperature damage type merely inferior to creep and fatigue of turbine materials. The virgin materials are obtained through alloy smelts firstly. Then they are subjected to heat treatment according to the GE step cooling treatment criterion. The FATT50 value of all the materials increased after the treatment, thus the virgin and the embrittled materials are obtained. The electrochemical polarization test was found to be a very good measure of embrittlement. The test results at different temperature indicate that there is an evident correlation between the characteristic current peak Ip and the FATT50 value of the materials. The Ip value increases and then decreases with the rise of the test temperature. Regard the temperature as an independent factor, multiple regression analysis is conducted considering variables which are known or are nondestructively measurable. The reason that the factors are chosen lies in the remarkable correlation between them and the FATT50 value of the materials. In such way a prediction model is established. The validations of the model make clear that the effect of temperature on current is removed. As a result, a regression equation which gives an estimate of the actual FATT with the scatter of ±20℃is obtained to whether the test materials or new materials.
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