Влияние условий трубного передела и структурного состояния на эксплуатационную надежность высокопрочных трубных сталей

Operation reliability of a pipeline depends on many factors, including conditions of pipe forming, and a type of structure of pipe steel. Results of study of mechanical properties, impact toughness, crack resistance of pipe steel variation as a result of deformation aging depending on modes of pipe production and type of steel structure state presented. It was shown that standard mechanical properties practically don’t depend on the place of sampling in most extreme sections of pipe circumference and method of deformation at their manufacturing. Most favorable variation of impact toughness parameters and crack resistance was discovered for pipe metal, obtained by deformation schemes in rolls and UOE-forming, where increasing of their characteristics is observed. At the step forming JCOE a considerable scatter of impact toughness values over section of a pipe workpiece was noted, which decreased in the finished pipe. It was shown that deformation aging results in a decrease of deformation ability of the metal, cold resistance, crack resistance, which is most typical for steel with bainite structure. It was established that deformation aging of bainite steel to a greater extent decreases the crack resistance (the work of initiation, the work of propagation of a crack, its critical opening) at static tests for bending, than that of ferrite-perlite steel. Therefore, as a result of deformation aging, the destruction resistance of pipe steels with bainite structure decreases to a greater extent.