Method and device for reducing temperature of thin-strip continuous casting lower closed chamber

Abstract

The invention discloses a method and device for reducing the temperature of a thin-strip continuous casting lower closed chamber, and relates to the field of thin-strip continuous casting. The problem that an existing process cannot give consideration to strip steel anti-oxidation and rolling temperature reduction of the thin-strip continuous casting lower closed chamber at the same time is solved; the following improvements are performed on the basis of an existing dual-roller thin-strip continuous process, wherein the improvements include that liquid nitrogen is injected into the closed chamber, a plurality of channels leading to the lower closed chamber are evenly distributed on the surrounding wall of the thin-strip continuous casting lower closed chamber, and the liquid nitrogen is injected into the channels; the flow and the pressure of the liquid nitrogen in each channel are adjusted; and closed-loop control over the oxygen concentration of the lower closed chamber is carried out; and closed-loop control over the online rolling temperature is carried out, and the inlet temperature is controlled to range from 900 DEG C to 1150 DEG C. By means of the method and device, the aim of rapid cooling of the thin-strip continuous casting lower closed chamber can be achieved, steel strip oxidation is effectively prevented, the lower steel strip rolling temperature is achieved, the steel strip cooling homogeneity is improved, and the plate shape and the surface quality of strip steel are better improved.

Description

technical field [0001] The invention relates to the field of thin strip continuous casting, in particular to a method and device for reducing the temperature of a closed chamber under thin strip continuous casting. Background technique [0002] In recent years, domestic and foreign research activities on the development of direct casting technology for steel strip (that is, near-net-shape processing technology for strip steel) have become more and more active, and the fastest growing technology is twin-roll thin strip continuous casting technology. [0003] The twin-roll strip continuous casting technology was first proposed by Henry Bessemer in 1865 (US Patent: 49053). Thin strip continuous casting integrates continuous casting, rolling, and even heat treatment into one process, so that the produced thin strip can be rolled into industrial products at one time, which greatly simplifies the production process from molten steel to steel strip and shortens the production proce...

AI Technical Summary

Problems solved by technology

[0008] In addition, in the conventional thin strip process, there is still a big problem, that is, the temperature of the steel strip before entering the rolling mill is often as high as 1200°C or even above 1250°C. At this time, the strip steel is very soft and its high temperature strength is very low. , resulting in the inability of the on-line rolling mill to exert a large rolling force, it is difficult to roll effectively, and the shape of the rolled plate cannot meet the requirements of the product

In order to reduce the rolling temperature of the steel strip, some manufacturers spray water to cool the strip before the rolling mill. The contact between the high-temperature strip and the cooling water will cause many problems: (1) The contact between the high-temperature strip and the cooling water, the surface of the steel strip (2) The cooling water will form water spots (rust spots) on the surface of the strip steel, which will affect the surface quality; (3) The cooling water will easily cause uneven cooling on the surface of the strip steel, resulting in the internal microstructure of the strip steel. Inhomogeneity, resulting in uneven properties of the strip, affecting product quality; (4) uneven cooling of the surface of the strip, which will cause the deterioration of the strip shape and affect the quality of the strip shape

[0009] The above-mentioned patents or usage schemes all solve the problem unilaterally, or solve the problem of anti-oxidation of the steel strip in the airtight chamber alone, or solve the problem of cooling the airtight chamber alone, or solve the problem of reducing the temperature of the steel strip alone. For the problem of rolling temperature, none of these measures has provided a solution that simultaneously takes into account the anti-oxidation of strip steel in the closed chamber under thin strip continuous casting, reduces the drop in closed room temperature, and effectively reduces the rolling temperature of the steel strip.

Images