Quality of Ст3сп steel reinforcement (class A500S) thermally hardened in a 280 mill

Thermal hardening of Ст3сп steel rolled in the 280 mill at the LPZ casting and rolling plant is developed, so as to produce reinforcement (diameter 14–18 mm) of strength class A500S according to the STO ASChM 7–93 standard. The strength of the metal, whether supplied to the mill in the hot or cold state, is the result of discontinuous quenching with variation in mean-mass self-tempering temperature within the range 565–575°C. The macrostructure, microstructure, and fine structure of the thermally hardened bar is investigated. The properties of the bar are ensured by the structure formed as a result of hardening and subsequent cooling on the roller conveyer and in the cooling unit: mainly tempered martensite in the surface layer; ferrite and cementite in the core of the bar.