| 摘要 |
PURPOSE:To enable prompt judgement of the presence or absence of any flaw, the kind of whether a cracked flaw or decreased hardness, the size of the flaw and the shape of the flaw by comparing the two-dimensional flaw map which is analogically and digitally displayed. CONSTITUTION:The eddy current flaw detection signal from a detector 4 is divided to two. Phase shifters 7 and 13 rotate said signals to the phase angles at which a crack flaw and hardness decrease are detected respectively with good S/N. The signals are then inputted to phase detectors 8, 11 and are synchronously detected. The signal A past a filter 9 set at the high frequency band where the crack flaw is easily detectable is lowered in the frequency level of the flaw signal by a peak expander 14 and is analogically recorded like (c) in an X-Y recorder 19 in synchronization with a probe position detector 23. The output B of a filter 12 set at the low frequency band where the hardness decrease is easily detacable enters a divider circuit 16 together with the output A, by which B/A is calculated. The crack flaw and the hardness decrease are discriminated from the value thereof and the result is digitally displayed like (b) on a CRT or printer. |
