A production method for continuous casting of steel slabs containing rare earth elements

Abstract

The invention discloses a steel containing rare earth element and a producing method of slab continuous casting. The steel comprises the elements of Re, C, Si, Cr, Ni, and N according to a certain ratio, and the balance of iron and inevitable impurity; the production method comprises a ladle furnace refining process and a continuous casting operation; wherein, in the ladle furnace refining process, feeding metal Ca wire before rare earth is added in molten steel, then feeding rare earth metal wires, simultaneously passing the rare earth metal wires through the surface of slag, feeding the metal Ca wires again, controlling the weak stirring time of ladle furnace refining and slag interfacial fluctuation area; and in the continuous casting process, controlling the super-heated rate of molten steel in a tundish at 35-65 DEG C, and controlling the inserting depth of an port of a continuous casting crystallizer at 100-135 mm. Compared with the prior art, the method has the advantages of high rare earth yielding rate, and good continuous casting surface and center quality, impurity in the steel is effectively removed, and rare earth yielding rate is stable.

Description

technical field [0001] The invention relates to a production method for continuous casting of steel slabs containing rare earth elements, and belongs to the technical field of steel smelting. Background technique [0002] In addition to deoxidation, desulfurization and control of sulfide form in steel, rare earth (Re) has microalloying and dispersion strengthening effects. It can improve the as-cast structure and inhibit grain growth, thereby improving the impact toughness of steel, improving thermoplasticity, oxidation resistance, etc. Rare earths can interact with low-melting-point impurities such as phosphorus, arsenic, tin, antimony, bismuth, and lead in steel to form high-melting-point compounds and inhibit the segregation of these impurities on grain boundaries. Rare earth elements have low melting points and active chemical properties, so the control of the amount of rare earth elements is particularly critical. [0003] Rare earth has a strong affinity with oxygen,...

AI Technical Summary

Problems solved by technology

The problem of rare earth alloying in the ladle refining process is that if the timing of rare earth addition is too early, the rare earth will form a large number of oxides or sulfides, etc., and the yield of rare earth is low; if the timing of addition is too late, the inclusions generated by rare earth are difficult to float and remove. Uneven distribution in steel

[0004] The main problems of using slab continuous casting to produce rare earth-containing steel are difficult to control the degree of superheat, low casting speed, and poor quality of the surface and center of the slab.

The fluidity of molten steel is poor. When the pouring temperature is too low, the mold nozzle will be frozen and the pouring will be interrupted, which is not conducive to the floating of inclusions. Segregation and porosity

It is difficult to control parameters such as casting speed, mold nozzle insertion depth, and secondary cooling intensity; in addition, it is difficult to alloy rare earths, which leads to difficulties in continuous casting of rare earth-containing steel slabs, and it is difficult to achieve continuous casting in multiple furnaces

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