| 摘要 |
PURPOSE:To easily find corrosion, life, and time strength by means of the number of breaking receptions being 10<9> or more, by detecting a change in an amplitude of a vertical vibrationthrough the production of a crack due to corrosion in a surface layer of a sample by ultrasonic vibration. CONSTITUTION:Ultrasonic wave, produced by an ultrasonic wave oscillator 4, is transmitted to an ultrasonic wave vibrator 1, and is expanded by an amplitude expanding horn 2 to provide a vertical vibration to a sample 3. The sample 3 is immersed in a corrosion liquid tank 13, and corrosion liquid is cycled between the tank 13 and a storage tank 11, which results in performing a simultaneous corrosion fatigue test when the sample 3 is cooled. If a minute corrosion fatigue crak is gnerated in the surface layer of the smple 3 after a test is conducted for a long period of time, a change in the inherent number of vibrations of the sample 3 is produced, and an amplitude of vertical vibration also changes. A change in impedance of an ultrasonic wave current, produced due to a change in the amplitude, is detectd by a detector 6, and a constant-amplitude control circuit 7 and a clock 9 are caused to stop actuating by means of the detecting signal to suspend vibration of the sample 3. |
