Calcium treatment method of ultra-low-carbon and high-aluminum steel

Abstract

The invention discloses a calcium treatment method of ultra-low-carbon and high-aluminum steel. The calcium treatment method mainly solves the technical problem that when an existing slab caster casts ultra-low-carbon and high-aluminum steel comprising 0.001%-0.01% of carbon and 0.1%-0.3% of aluminum, a continuous casting water gap is knotted. The calcium treatment method of ultra-low-carbon and high-aluminum steel comprises the following steps that firstly, decarburization is carried out on molten steel in an RH furnace inlet station for 10-20 min under the vacuum degree of 270 Pa; secondly, silicon is adopted for decarburized molten steel for deoxidation, circulation is carried out for more than three minutes, an appropriate number of aluminum blocks are added to the component design range, circulation is carried out for more than five minutes under the situation that the circular flow is 1,600-3,000 L / min, and Alt and Als in the detected molten steel are sampled; thirdly, calcium iron alloy blocks are added through an RH furnace burden bin to carry out calcium treatment on molten steel, and the vacuum degree is reduced to 10-20 KPa; and after the calcium iron alloy blocks are added, circulation is carried out for more than three minutes in the state that the circular flow is 1,400-2,500 L / min. Compared with a common calcium treatment technology, the continuous casting water gap is effectively prevented from being knotted.

Description

technical field [0001] The invention relates to the technical field of steelmaking technology, in particular to a calcium treatment method for ultra-low-carbon high-aluminum steel. Background technique [0002] When casting aluminum-killed steel in steelmaking, especially ultra-low carbon high-alumina steel with a carbon content of 0.001-0.01% and an aluminum content of 0.1-0.3%, solid Al 2 o 3 At the same time, aluminum in molten steel is easy to be oxidized again, forming high-melting point oxides, resulting in nodulation of stopper rods and nozzles, affecting production rhythm and deteriorating the purity of molten steel. [0003] Usually, in order to solve the problem of easy blockage of the nozzle when aluminum deoxidized steel is cast, calcium treatment is added after refining to make Al with high melting point 2 o 3 The inclusions are denatured to produce liquid calcium-aluminate C12A7, which is easy to float. If too much calcium is added, it is easy to form inc...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a calcium treatment method for ultra-low-carbon high-aluminum steel, which mainly solves the problem of casting carbon content of 0.001% to 0.01% and aluminum content of 0.1% to 0.3% in the slab continuous casting machine in the prior art. Ultra-low-carbon high-aluminum steel continuous casting nozzle nodules, large inclusion content, reduced purity of molten steel, and difficult to precisely control the amount of calcium-iron alloy block added

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