INFLUENCE OF TEXTURES OF PIPELINE STEELS AFTER OPERATION ON THEIR BRITTLE FRACTURE RESISTANCE

The difference between the brittle fracture resistances of ferrite-pearlite steels in the as-received state and after operation is determined, depending on the orientation of the specimens, by the impact toughness testing of Charpy specimens cut out in different directions relative to the axis of the pipe. The longitudinal specimens exhibit the highest level of impact toughness, the transverse specimens have a somewhat lower level impact toughness, and the radial specimens whose fracture plane is parallel to the rolling plane revealed the lowest impact toughness. The long-term operation of steels significantly decreases their brittle fracture resistance. In this case, the impact toughness of radial specimens was, as a rule, lower than the normative values specified in the industry.