Abstract：In view of the longitudinal crack of high carbon steel tool steel SK85 produced by continuous casting in Tanggang New District, the mechanism of surface longitudinal crack of casting billet and the actual characteristics of defects were analyzed systematically, and effective measures were taken to reduce the incidence of longitudinal crack of slab SK85 steel. The main reason of surface longitudinal cracking of SK85 steel in Tangsteel New District slab continuous casting is that the superheat of molten steel, the control of mold heat flow parameters and the precision management of continuous casting machine equipment do not meet the requirements of high carbon steel characteristics. By reducing the superheat of molten steel in continuous casting to 18-26 ℃, stably controlling the range of 1.0-1.2 m/min in continuous casting drawing speed, adjusting the water flow of mold and the temperature difference between inlet and outlet water to control the heat flow of mold to 1.6-1.9 MW/m2, ensuring the arc accuracy of the fan section and mold in continuous casting, and strictly controlling the surface longitudinal cracking of SK85 with immersion nozzle. The incidence of longitudinal crack is stabilized to less than 5%. The research results described in this paper have positive reference significance for the research and development and production of high carbon tool steel in similar steel plants.
2023, Vol. 42 
