| 摘要 |
PURPOSE:To perform a hot flaw detection of a ferromagnetic substance by providing a circuit for compensating for changes in the sensitivity and phase of an output signal of a flaw detection sensor due to the temperature of material to be detected. CONSTITUTION:A material to be detected (not illustrated) maintained a high temperature by heat is arranged in a circular magnetized coil (not illustrated). Flaw detecting heads (not illustrated) are arranged so radially as to evenly cover flaws over the entire surface to be detected. Outputs of flaw detection sensors 2a-2n mounted on the flaw detecting heads are amplified with amplifiers 37a-37n, then, compensated for changes in the sensitivity and phase thereof with variable attenuators 38a-38n and phase detectors 39a-39n and sent out through filters 40a-40n. The attenuators 38a-38n and phase detectors 39a-39n operate in response to the outputs of temperature measuring elements 36a-36n for detecting the surface temperature of the material being detected. Thus, a hot flaw detection can be done accurately. |
