| 摘要 |
PURPOSE:To non-destructively quantitatively predict the remaining life of austenite stainless steel by obtaining the attenuation ratio of ultrasonic wave from a bottom echo in a specific high frequency band, and collating it with a graph showing the relationship between a previously obtained attenuation ratio and a creep life consumption ratio. CONSTITUTION:The method for predicting the remaining life of austenite stainless steel comprises the steps of oscillating ultrasonic pulse to the steel material (using steel material) being used in a high-temperature environment, measuring two arbitrary bottom echo outputs in a high-frequency band remarkably represented in terms of the difference of the attenuation ratio between the using steel material of the same steel type and unused steel material, developing the relationship between the amplitude and the frequency by Fourier transformation from the relationship between the amplitude and the time, and calculates the attenuation ratio of the using steel material from the ratio of the amplitudes. Then, the attenuation ratio is collated with the graph showing the relationship between the attenuation ratio previously obtained from the destructive inspection and the creep life consumption ratio, and the creep life of the using steel material (the steel material to be detected) is obtained. Thus, the remaining life of the using steel material can be non-destructively predicted. |
