| 摘要 |
PURPOSE:To perform the measurement of a transformation amount with high accuracy, by collecting leak magnetic flux from a wide range by providing a magnetic flux focusing device while detecting the difference between the measured values of a magnetic flux detector when a magnetic field is high and low by using a pulse magnetic field generating apparatus. CONSTITUTION:A pulse like exciting current is flowed to an exciting coil 3 by the signal 17 from a pulse magnetic field generating control apparatus 9 and pulse magnetic flux 5 is generated from a magnetic pole 2. The magnetic flux 5 is separated into magnetic flux 51 passing the interior of a material 1 to be measured and magnetic flux 52 leaked to the outside while the latter is gathered from a wide range by a magnetic flux focusing device 7 and focused to a magnetic flux detector 6 to be detected. An operation appratus 12 takes in a material signal 13, a plate shape signal 14, a processing condition signal 15, a leak magnetic flux detecting signal 10 and a temp. signal 11 and the difference of signals 10 when the exciting current is high and low is operated to measure leak magnetic flux intensity. Because leak magnetic flux intensity is changed corresponding to the transformation amount of the material 1 to be measured, the transformation amount can be detected. |
