| 摘要 |
PURPOSE:To make it possible to perform the detection of a welding defect in a real time in all welding methods and all kinds of steels, by employing an AE measuring method wherein a welding metal temp. range of 750-450 deg.C is set to a monitor range. CONSTITUTION:AE sensors 11, 12 ... are arranged to an object to be welded at predetermined intervals and detect AE signals emitted from a welding metal set to a temp. range of 450-750 deg.C in the vicinity of a welding torch position. The output signals of said sensors are applied to a signal treating circuit 5 through preamplifiers 21, 22 ..., filters 31, 32 ... and main amplifiers 41, 42 .... In the circuit 5, a time difference measuring instrument successively measures the difference of times when the sensors receive the signals and a ring-down count counter counts the number of times when the first arrival signal cuts a certain threshold value in a positive gradient while one set of data consists of the first arrival sensor number, the time difference measured result and the counted result to be outputted to a calculator 6. When the calculator 6 discriminates that said data are right, said data is displayed by a display apparatus 8 through an interface 7. |
