TW347466B - Method for nondestructive inspection of metal welding and apparatus therefor - Google Patents

Abstract

A method for nondestructive inspection of metal welding, which comprises: (1) installing two sets of electrically conductive clamps separately clamped on a pipe body under detection, and separately clamped on the two sides of the welding position; connecting the two sets of clamps on a current wire; (2) installing a current sensing element on the current wire and connecting in series to a constant current source unit; (3) outputting a constant current from the constant current source unit through the current wire to one of the clamps, and feeding back to the other clamp through the welding place of the pipe body, thereby forming a closed loop; (4) installing a fixed-point temperature sensing element near the welding place, and setting up a parameter according to sensed different temperatures; (5) rotating the pipe body under detection and/or temperature sensing element; (6) detecting the magnitude of the current by the current sensing element; (7) transmitting the detected current signal to a current signal processing unit; (8) calculating the current signal by the current signal processing unit, and driving the constant current control unit according to the result of calculation, thereby controlling the current outputted by the constant current source unit.