Abstract: The present invention pertains to a method for the nondestructive testing of pipes made of ferromagnetic steel by means of a stray flux, in which the pipe, which is moving in the longitudinal direction and alternatively additionally rotating, is magnetized by a constant field, and the generated magnetic flux is transmitted into the pipe in a contactless manner, and the flaws that are located in the near-surface area of the outer or inner surface of the pipe bring about magnetic stray fluxes, which emerge from the pipe surface and are detected by means of sensors. The amplitudes, preferably of the horizontal field component of the magnetic stray flux, which vary in the vertical direction, are detected, on the one hand, at a near-surface distance from the pipe outer surface, and, on the other hand, at a distance lying further remotely therefrom, and the detected signals are related to one another. Furthermore, the present invention pertains to a device for carrying out the method.
Type:
Application
Filed:
June 10, 2005
Publication date:
February 21, 2008
Applicant:
V.& M. DEUSCHLAND GMBH
Inventors:
Michael Kaack, Stefan Nitsche, Thomas Orth