Continuous casting and rolling production line capable of avoiding ferrite rolling mixed crystal and production method

Abstract

The invention belongs to the technical field of metallurgical processes and equipment, and relates to a continuous casting and rolling production line capable of avoiding ferrite rolling mixed crystals and a control method. The invention discloses a continuous casting and rolling production line capable of avoiding ferrite rolling mixed crystals. The continuous casting and rolling production line comprises a continuous casting machine, a roughing rolling unit, an intermediate billet heat preservation device, a finishing rolling unit, an after-rolling cooling device, a high-speed flying shear and a coiling unit which are sequentially arranged along a rolling line. A rolled piece heating device, a descaling device, an accident handling device, an intermediate billet cooling device and the like can be arranged on the production line according to needs. The intermediate billet heat preservation device is arranged in front of a finishing mill group, the temperature of the intermediate billet when reaching an inlet of the intermediate billet heat preservation device is controlled to be below the ferrite phase change temperature, the heating temperature of the intermediate billet heat preservation device is controlled, the intermediate billet is subjected to heat preservation or slow cooling in the device, the austenite-ferrite phase change time is prolonged, and the production efficiency is improved. And phase change is fully carried out, mixed crystals caused by double-phase rolling are avoided, and the structure property uniformity of a ferrite rolled product is improved.

Description

technical field [0001] The invention belongs to the technical field of metallurgical technology and equipment, and in particular relates to a continuous casting and rolling production line and a production method that avoid ferrite rolling mixed crystals. Background technique [0002] In the field of hot-rolled strip steel production, compared with traditional hot continuous rolling, the thin slab continuous casting and rolling process has short process flow, low energy consumption and high yield, which has significant advantages. Since the first CSP production line was put into operation at the Nucor steel plant in the United States in 1989, the thin slab continuous casting and rolling process has developed rapidly. According to statistics, 67 102-strand thin slab continuous casting and rolling lines have been built in the world, with an annual production capacity of 110 million tons; my country also has a total of 20 36-strand thin slab continuous casting and rolling produ...

AI Technical Summary

Problems solved by technology

At present, the typical continuous casting and rolling production lines are basically designed based on the traditional austenite rolling process, and it is difficult to realize ferrite rolling. Transformation has realized the ferrite rolling of part of the finish rolling stand. Based on the deficiency of partial ferrite rolling, some researchers have proposed a variety of thin slab continuous casting and continuous production lines that can perform full ferrite rolling of finish rolling. Scheme and production method

[0004] The current thin slab continuous casting and rolling ferritic rolling scheme, whether it is part-stand ferritic rolling for finishing rolling or full ferritic rolling for finishing rolling, has a common problem: the rolled piece is transformed from austenite to iron During the phase transformation process of ferrite, the temperature drop is faster, the phase transformation time is shorter, and the transformation from austenite to ferrite is not sufficient. When the rolled piece enters the rolling mill at the temperature of ferrite zone for rolling, the phase transformation does not actually occur. Fully completed, rolling in the two-phase region will occur, resulting in mixed crystals and deteriorating the microstructure and properties of the finished strip

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