The most important findings of this investigation pertaining to the effects of direct quenching parameters on the strength, hardness and microstructure development of low (0.04-0.17%) C-Mn-(Cr) steels microalloyed with Mo-Al-(Ti)-V or Nb with and without B, both in laboratory and full-scale processing are summarized below: • The reheating temperature and accelerated cooling rate following TMCP processing have shown the strongest effect on the mechanical properties of the present steels in the as DQ condition. • ThermoCalc calculation was very useful for predicting the reheating temperature for optimizing the austenite microstructure before TMCP processing of the present steels. • Microstructures and mechanical properties of the present steels after plate rolling simulation in laboratory scale show that the lower reheating temperature together with a high FRT and high cooling rate have a very positive effect on improvement of properties. • The best combinations of strength properties of the present steels were obtained for the low reheating temperature (1,120°-1,160°C) with a high reduction during hot rolling and high finish rolling temperature (FRT ≥900°C) followed by accelerated cooling rate of 40-60°C/s to RT. • The mechanical properties values obtained for full-scale TMCP processed plate are in a good agreement with the results from the laboratory TMCP simulations processed in a similar manner. • Optimization of thermomechanical / direct quench processing of high-strength products allow elimination of a reheat hardening treatment and improve productivity aspects. • Low slab reheating temperature and finish rolling parameters reduce energy consumption during the thermomechanical processing. • Mechanical properties are affected by the scale and morphology of martensite, and to some extent the volume fraction of bainite in the microstructure. Cooling rate is a very important factor, which controls the transformation and precipitation during quenching. • The important findings concerning high-strength in very low-carbon bainitic steels show that the yield stress of ∼800MPa is obtained for direct quenching processed plate with cooling rates of 30°C/s. • Results of this study show that to obtain sufficient bainite hardenability of very low C steel, a base composition of 1.4Mn-1.0Cr -0.25Mo is necessary.