| 摘要 |
PURPOSE:To enable the automation of a quenching process, by detecting a quenching crack at the time of quenching with sufficient accuracy by utilizing only an AE wave generated for a period having possibility generating the quenching crack in high frequency quenching. CONSTITUTION:The AE wave generated from a quenching member 1 is received by the sensor 3 arranged to a chuck 2a for a period having possibility generating a quenching crack and subjected to envelope detection (h) by an envelope detector circuit 9 through a filter 8 to be inputted to a limiter 15. A signal (i), which is obtained by processing the output signal of the detector circuit 9 while amplifying the processed signal by minute voltage (DELTAV) in an amplifier 17, is also inputted to the limiter 15 and converted to pulse like output which is, in turn, outputted to a NAND circuit 18. When a limit switch 25 is pushed, a signal (c) of logic 1 is inputted and an AE wave only for this period (a quenching period) is measured. Only the AE wave is converted to pulse like output (j) by the NAND circuit 18 and a pulse number is counted by a counter 20. By the comparison of the measured value with the set value of a superiority and inferiority judgment setting circuit 19, an inspection result display part 23 is operated through TF22 to perform the automation of quenching process. |
