The effect of rolling modes and cooling conditions on the structure and mechanical properties medium-carbon manganese low-alloy steels of type 38G2F is investigated. The critical temperatures Ac1 and Ac3 are determined. The characteristics of the ferrite, pearlite and bainite structural components (the content and the morphology) and the sizes of the initial austenite grains in pipes with different wall thicknesses are determined. Tensile mechanical tests are performed. It is shown that the high level of mechanical properties (σ0.2 > 650 MPa, σr > 900 MPa) of the pipes with wall thickness 16.0 mm is a result of the presence of bainitic component in the structure. It is suggested that the temperature of heating of the pipe billet for rolling should be reduced from 1230 – 1260°C to 1170 – 1180°C for manufacturing pipes with a size of ∅93.2 × 13.0 mm and ∅127 × 16.0 mm. The combination of their mechanical properties matches the E strength group.