| 摘要 |
PURPOSE:To make possible the exact discrimination of defectiveness or non- defectiveness by measuring the spacing between the echoes corresponding to the thickness of a weld zone, appropriating proportionally the spacing to the ratio of the thickness of stock constituting the weld zones and setting the discrimination point. CONSTITUTION:AO is the first transmission wave, Aoa is the 1st base reflection wave of the weld zone, Aob is the 2nd base reflection wave of the weld zone and A1, A2 are the reflection waves from the contact surfaces of the constituting stock. The spacing between Ao and Aoa corresponds to the thickness of the weld zone. The position of A1, A2 corresponds to the thickness ratio with respect to the spot weld zone superposed with two sheets of the plates having different thicknesses. A1, A2 do not appear when the nugget larger than the sound flux is formed in the spot weld zone. The waveform and amplitude of the echoes in the positions A1, A2 change according to the defectiveness and non-defectiveness of the spot welding and the discrimination of the defectiveness and non-defectiveness of welding is made possible by the presence or absence of the echo waveform and the magnitude of the amplitude at said point. |
