INCREASE IN PRODUCTIVITY OF SLAB CONTINUOUS CASTING MACHINE IN THE STEELMAKING PLANT OF JSC URAL STEEL

Abstract

After commissioning of Continuous Casting Machine No. 2 in the Steelmaking Plant of JSC Ural Steel in 2004, it became possible to produce slabs 1200 mm wide and 190 and 270 mm thick of a wide range of steel grades. The machine was equipped with a resonant mold with vertical support rollers, it is equipped with an early breakout detection system with an automatic mold level control unit and a secondary water cooling system. Strand cooling rate changes automatically depending on the steel casting speed. In the period from 2014 to 2017 during further revamping of the Continuous Casting Machine, its roller gap and strand secondary cooling modes were changed, additional side support rollers and nozzles were installed, changes were made to the design of the secondary cooling zone headers, etc. At the same time the following slab internal (macrostructure) quality was achieved: centerline porosity – rating of 0.5–1.0 point; centerline segregation (centerline chemical inhomogeneity) – rating of 0.5–1.0 point; nested cracks – rating of 0–0.5 point. In 2017 the production of 220 mm thick slabs was mastered. In 2022 phased work was started to increase the productivity of Continuous Casting Machine No. 2 without compromising quality of slabs and rolled plates. Cooling modes in the secondary cooling zone and mold cooling were adjusted, the temperature stability in tundish at the level of T_L + (10–20) °C was increased, the optimal casting powder was selected, and the roller gap was changed. After increasing the casting speed of 220 mm thick slabs from 1.2 to 1.45 m/min, 270 mm thick slabs from 1.0 to 1.08 m/min and implementing the above measures, a noticeable decrease in the formation of surface and internal defects in rolled plates was noted.