The influence of the structural state of the wall material of a seamless pipe made of 09G2C steel, after heat treatment under various regimes, on its mechanical properties was studied during uniaxial tensile testing in the temperature range of 20 to 400 °C and during impact bending testing in the range of 0 to –70 °C. It was shown that a bimodal banded structure of ferrite and tempered bainite, formed after quenching from the two-phase region and high tempering near the Ac temperature, exhibits a greater tendency toward both static and dynamic strain aging compared to the homogeneous structure of tempered bainite obtained by quenching from a temperature above Ac followed by high tempering. This effect is attributed to the increased carbon concentration in the solid solution and the small size of structural elements within the tempered bainite bands. Additionally, the impact strength of the pipe wall material with a homogeneous structure decreases as the test temperature drops below –40 °C, whereas the impact strength of the material with a bimodal banded structure remains stable down to –70 °C, which is attributed to its layered morphology.
Pyshmintsev et al. (Wed,) studied this question.