| 摘要 |
PURPOSE:To detect a flaw in a weld zone with high precision by oscillating an ultrasonic wave beam converged through a medium to left and right about a center weld line, and successively monitoring echo from a position corresponding to the bottom surface thickness of a flange member while transporting shape steel whose flaw is to be detected forward and backward. CONSTITUTION:An ultrasonic wave probe 1 uses a convergence type probe and a thin beam 1' is made incident to a flange member (a) at right angles from the top surface through a medium 3 such as water. When an oscillator diameter is 6mm., a flaw detection frequency is 10MHz, and focal length is 15mm., the incidence of a thin beam with an about 0.5mm. diameter is possible. Then, the oscillator while oscillating at, for example, 20-50Hz oscillation frequency to left and right (at right angles to the transportation direction of H shape steel, i.e. horizontally in figure) moves welded shape steel forth and back to monitor echo from the bottom surface of the flange member for a faulty part. This method allows flaw detection within the amplitude range of the probe even when a weld line deviates to left and right, so high-precision inspection is performed. |
