| 摘要 |
PURPOSE:To perform the correct depth measurement without any effect of a gap, by making the iron loss of a quenched layer of a material to be measured correspond to the product of the sum of the 16th power and square of incoming magnetic flux and a coefficient based on the depth of the quenched layer. CONSTITUTION:A coil 7 is wound around the material to be measured 2 by an appropriate number of turns. An integrating circuit 8 comprising, e.g. a capacitor C and a resistor R, is connected across both ends of the coil. A synchroscope 9 is connected to the capacitor C. An AC power source 4 is adjusted so that the amount of the magnetic flux at the quenched layer of the material to be measured 2 becomes a specified value. A voltage (e) is induced by the temporal change of the magnetic flux phi of the magnetic circuit yielded between an iron core 1 and the material to be measured. The integrated result of the voltage (e) from the integating circuit 8, i.e. the amount of the magnetic flux phi, is observed by the synchroscope 9. The AC power source 4 is adjusted so that said amount of magnetic flux becomes a preset value. Under this state, a power value is read of a wattmeter 5 as a value corresponding to the iron loss of the quenched layer of the material to be measured. The depth of the quenched layer of the material to be measured is measured from the power value. |
