Abstract

The results of the influence of preliminary thermal-cyclic deformation and subsequent hardening heat treatment on the microstructure and mechanical properties of hot-rolled sheet steel 10 are presented. It is shown that the use of preliminary thermal-cyclic deformation of the steel 10 stock material results in a fine-grained structure of a hot-rolled sheet (3 mm thick) produced by an industrial technology. Deformation occurred at a temperature above A_C3 (1250 °C), with cooling to 200-300 °C during 10 cycles and the deformation ratio per cycle being 6-8 %. The magnitude of the overall reduction ratio was 1.90 and the total amount of deformation was 65÷68 %. Such a treatment before sheet hot-rolling allows increasing the strength characteristics (tensile strength, yield strength) by almost 30 %. It has been established that the use of subsequent heat treatment (quenching, 900 °C, water and tempering 1 h, 600 °C) leads to a further increase in strength characteristics by 15-20 % while maintaining a sufficient level of ductility of sheet steel.