| 摘要 |
PURPOSE:To improve the reliability of machine parts used at a high temperature by making it possible that the growing state of a crack is detected directly without requiring stress estimation and monitoring a quick growth of the crack in a short time without overlooking. CONSTITUTION:A thermocouple 21 and an AE element 22 are provided in plural positions on the surface of a casing body 20 close to each other, and elastic waves which are discharged in accordance with the growth of a crack 41 are detected by AE elements 42-45 and are inputted to an AE analyzer 27, and the AE energy exceeding a set value is integrated, and the number of AE signals exceeding a certain crest value is counted, and the position of the crack 41 is determined on a basis of differences of detection time. Temperatures of thermocouples 42'-45' are measured by a temperature measurer 23 to calculate the temperature in the position of the crack 41. A waveform analyzer 28 judges whether the growth of the crack is in course of non-steady operation or steady operation, and a crack growth speed calculated by a crack growth speed calculator 29 is added in time series by an adder 30 to calculate dimensions of the crack, and they are displayed on a display device 37 through a discriminator 36, and an alarm is raised by an alarm device 38. |
