A method for improving the quality of continuous casting slabs

Abstract

The invention discloses a method for improving the quality of continuous casting slabs. The continuous casting slabs formed by cooling and crystallizing molten steel are drawn and straightened by a drawing and straightening machine, and the drawing and straightening of the continuous casting and drawing and leveling machine is performed in advance by means of current heating. The straightening rolls are preheated, and the temperature of the straightening rolls of the continuous casting straightening machine is preheated to 300-900°C to reduce the temperature difference between the continuous casting billet and the straightening rolls of the straightening machine and prevent the continuous casting billet from being too fast. Excessive heat dissipation, so as to avoid the crack sensitive temperature of the continuous casting slab, to reduce the risk of cracks and segregation due to the excessive temperature difference between the casting slab and the outside during the rolling process, so as to improve the quality of the continuous casting slab to obtain mechanical properties A good billet is convenient for further processing of the billet to improve the efficiency of the continuous casting process.

Description

technical field [0001] The invention relates to the technical field of steel plate production, in particular to a method for improving the quality of continuous casting slabs. Background technique [0002] In the continuous casting slab production process, due to the requirements of rolling specifications, yield and other requirements, the continuous casting slab needs to be cut into a certain length. The casting speed runs for a certain period of time, while the cast slab or slab is conveyed by the conveying roller or in the hot rolling process of the rolling mill, it is generally transported and produced in an open manner, and the billet is drawn at a low speed and hot in the continuous casting machine. The slab is exposed for a long time through this section. In this section, the slab has just finished solidification, and the slab temperature is the highest. Due to the large temperature difference between the roller shaft, the rolling mill and the slab, the heat dissipati...

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Problems solved by technology

[0003] In order to reduce the impact of the temperature of the slab or slab in the continuous casting or rolling process, the main method currently used is to use a thermal insulation cover on the roller shaft or slowly cool the slab into the pit to reduce the temperature difference at the end of the slab Great impact on product quality, but the function of the existing heat preservation cover is relatively single, the effect of temperature control and heat preservation is not obvious, and there is still serious heat dissipation, so the heat preservation effect is not ideal, which greatly affects the casting slab or strip rolling processing quality

This situation has the following defects: on the one hand, a part of the produced continuous casting slab is sent to the rolling steel for direct rolling through hot charging. On the other hand, another part of the continuous casting slab enters the billet stack for slow cooling and then rolls. During the process of continuous casting billet entering the billet stack for slow cooling, the end of the continuous casting billet returns to a higher temperature. , the temperature recovery speed is fast, resulting in defects such as end cracks, which may further expand in the steel rolling heating furnace, resulting in cracks at the end of the rolled material during the rolling process, and a large amount of waste, which seriously affects product quality and production costs.

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