Magnetic combined systems have been developed and implemented for the continuous control and identification of defects in electric-welded and tubing strings in the process of their fabrication or defectoscopy of pipes that were in operation. Automated control systems allow to scan pipes with and without rotation. Systems based on single-chip thin-film matrix transducers on the sapphire substrate have high sensitivity and allow detecting both surface and volume defects by the noncontacting method with a large gap and with high speed.
Thin-film matrix transducers are rather difficalt for fabricating multilayer structures. Each ferromagnetic film element in the matrix transducers is made of several layers of Fe (20 %) and Ni (80 %) permalloy alloy separated by insulating layers of silicon monoxide. Multilayer ferromagnetic element is applied on the chrome sublayer, which, in turn, is applied to the substrate of the aluminum or glass ceramics. Matrix transducers based on magnetosensitive elements can be fabricated in large quantities with identical characteristics, as a result of which it became possible to organize non-destructive testing of electrowelded and hot-rolled pipes throughout the whole scope.
The technology was developed related to the serial production of UMD-101M type installations for magnetic control of electric-welded pipes throughout the whole scope. UMD-121 installation for magnetic quality control of welded seams and the metal of the heat effected zone (up to 140 mm wide) of the longitudinal-welded electrically welded pipes with the diameter of 168–530 mm and the wall thickness up to 16 mm has been developed and is being implemented. UMD-104M type installation for control of the tubing strings, which were in operation, have been successfully used since 2011 in PAO LUKOIL. They are based on the single-chip thin-film matrix transucers made using up-to-date technologies. As magnetosensitive elements the transducers were used with the magnetoresistance anisotropy effect in the ferromagnetic film, in which the new principle of measuring the strength of the magnetic field proposed by the authors was implemented.
It is shown that the application of the up-to-date technologies for the fabrication of the single-chip thin-film high-resolution matrix transducers allow to significantly increase the functional capabilities of the flaw detector and ensures not only the reliable detection of all the impermissible defects, for example, discontinuities in the metal, wear of the pipe wall, displacement of weld seams edges and adhesions, but also higher indicators on reliability of transducers (failures are minimal).