Ultralow carbon aluminum silicon killed steel and production method thereof

Abstract

The invention provides an ultralow carbon aluminum silicon killed steel and a production method thereof. The production method of the ultralow carbon aluminum silicon killed steel comprises the following steps of: 1) smelting, pretreating molten iron, smelting by a converter, and carrying out RH refining, to obtain molten steel, wherein the molten steel comprises the following components by weight percent: less than or equal to 0.005% of C, 0.8-1.8% of Si, 0.4-1.2% of Mn, less than or equal to 0.2% of P, less than or equal to 0.005% of S, 0.2-0.6% of Al, less than or equal to 0.005% of N, less than or equal to 0.005% of O and the balance of Fe and inevitable impurities, wherein Mn%=a-k| Si-8.37Al|, k=0.286-0.975, a=11E-6.58, and E: the isometric crystal rate in the steel, which is more than or equal to 50%; 2) casting, casting at the speed of 0.6-1.4m / min, wherein the mean superheat degree of the molten steel is 5-40 DEG C, in the process of continuous casting, the water-ratio quantity of the cooling water is adjusted to be 100L / min-less than or equal to 190L / min, so that the isometric crystal rate of a plate blank can be improved, and the thickness and the development of the cylindrical crystal of the plate blank can be avoided, and the temperature of the surface of the plate blank at an outlet of a casting machine is controlled at 650-800DEG C. According to the invention, the control of the isometric crystal rate in the steel can be effectively realized under the condition that the superheat degree of the molten steel is higher.

Description

technical field [0001] The invention relates to a production method of killed steel, in particular to an ultra-low-carbon aluminum-silicon killed steel and a production method thereof under the condition of relatively high superheat of molten steel. Background technique [0002] The crystals grow in the same direction, and the resulting elongated crystals are called columnar crystals. The mechanical properties of columnar crystals have obvious directionality, poor in the transverse direction and good in the longitudinal direction, the casting is prone to transverse fracture, and impurities with low melting points are easily enriched on the grain boundaries to cause crystal defects. [0003] For ultra-low carbon aluminum-silicon killed steel, the lower equiaxed grain rate will also cause uneven corrugations on the surface of the finished strip along the rolling direction, similar to corrugation, commonly known as "corrugated defects". This defect can significantly reduce the...

AI Technical Summary

Problems solved by technology

[0009] The main disadvantage of this method is that it requires a narrow range of molten steel superheat, which is difficult to effectively control, and also affects the normal operation of continuous casting

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