Abstract: During the pouring process of aluminum-free and non-oriented silicon steel, the liquid level fluctuation range of the mold reaches ±10 mm, which seriously affects the quality of the slab and the production of the slab. The thermal conductivity, bulk modulus and elongation of aluminum-free steel were analyzed by high-temperature mechanical simulation and tensile test, and the proportion of austenite precipitation in the slab condensation temperature range of 1 080~1 250 ℃ was 44 %. The bulging belly of the billet in the fan-shaped section is the main reason for the fluctuation of the liquid level of the mold during continuous casting. By reducing the tundish temperature, accurately controlling the refining components, and optimizing the flow rate of the secondary cold water, the proportion of the liquid level fluctuation≤±3 mm of the mold was increased from 58.6 % to 99.5 %.

Key words: non-oriented silicon steel, liquid level fluctuations, secondary cooling water, bulging belly, austenite