Ivantsov S. Impact of the structure parameters on the kinetics of fracture of microalloyed constructional steels

The object of study - the processes of phase transformations and microstructure formation and properties in low carbon steels. Purpose - to improve and stabilize the mechanical properties, particularly toughness steel plates of low carbon microalloyed steels based on setting the parameters of the relationship structure, fine structure and surface damage. The paper used modern methods and research techniques, light microscopy, diffraction and scanning electron microscopy, mikrofraktohrafichnyy analysis, static and dynamic mechanical testing. The present paper presents results of conducted research and experimental developments aimed at bringing solutions to topical scientific and practical tasks. The relationship between the size polygons (subgrain) ferrite after hot deformation and diameter pores, that formation the surface fracture and impact resistant heavy plate up to 40 mm with low-carbon low-alloyed steel was found. Short cooling to 50...150 150 after hot deformation effectively contribute to the stabilization polygonized structures of ferrite. Development of primary recrystallization thru the hot deformation ferrite and saves fine grain and to provide high toughness in the finished product from HSLA steel. Stabilization of mechanical properties of heavy plate for building construction was achieved. A technological process controlled rolling of heavy plate 40mm of 10Г2ФБ was proposed. This allowed reducing of high performance toughness and amount of defects concerning this index.