Application of HF Constant Potential Technique to NDT Process for Helical Weld Pipe

Described in the paper is the application of the HF constant potential technique with operation frequency over 80 kHz to the X-ray detection process for helical weld pipes.With the said technique,the highpower field effect tube(IGBT) is used to produce HF pulse voltage via the AC-DC-AC reverse transformation mode,and the pulse width is adjusted under fixed frequency via the feedback signal from the closed-loop circuit so as to bring about control of the hi-tension circuit and primary circuit of the high-voltage transformer.Thanks to such a technique,certain chronic problems as staying with the power frequency X-ray detection operation.