Method for increasing fast replacement success rate by decreasing drawing speed through continuous casting machine

Abstract

The invention relates to the technical field of steelmaking, in particular to a method for increasing the fast replacement success rate by decreasing the drawing speed through a continuous casting machine. According to the method for increasing the fast replacement success rate by decreasing the drawing speed through the continuous casting machine, the drawing speed is decreased when a tundish isreplaced, the time of passing of a casting blank through a secondary cooling chamber is prolonged, and thus the cooling strength of the casting blank is improved; the temperature of the casting blankis lower before the fast replacement drawing speed returns to zero, in this way, the relative deformation quantity of the casting blank staying in the secondary cooling chamber is smaller in the period that the fast replacement drawing speed returns to zero and casting is started again, it is ensured that when a new tundish starts to be cast, the casting blank can be normally drawn out of a crystallizer under the current pressure of straightening rollers, straightening cracks are avoided, the success rate of fast replacement and casting starting is increased, the quality of the casting blank is guaranteed, and operation is easy; and in addition, when casting is started again, connecting rods are utilized as a connector, after high-temperature molten steel flowing into a copper pipe in thecrystallizer makes contact with the connecting rods, heat of the molten steel is absorbed, the molten steel is solidified while the connecting rods are smelted, thus the connecting effect is achieved,the breed-out situation is avoided, and successful casting starting is guaranteed.

Description

technical field [0001] The invention relates to the technical field of steelmaking, in particular to a method for reducing the casting speed of a continuous casting machine and increasing the success rate of quick change. Background technique [0002] In the steelmaking and continuous casting production process, when the tundish needs to be replaced after the casting service life has been reached or the cast steel grade has reached the production requirement, the online continuous quick change mode is usually adopted, which saves the need to re-send the dummy and start again. Pouring time, improve the operation rate of continuous casting machine. [0003] The single-point straightening machine for continuous casting machine has the characteristics of low equipment investment cost, simple equipment structure, and convenient maintenance. Therefore, the current billet continuous casting machine mostly uses single-roll single-point straightening and straightening machine. [00...

AI Technical Summary

Problems solved by technology

[0004] Due to the fast casting speed of the billet continuous casting machine, the straightening temperature of the cast billet after leaving the secondary cold room is high. The casting speed of the old tundish is completed by using the normal process casting speed, and the casting speed is returned to zero for quick change. Due to the normal process casting speed Fast, generally in the range of 1.9 to 2.3m / min, before the pulling speed returns to zero, the surface temperature of the slab from the tension leveler to the lower mouth of the crystallizer is high, until the new tundish is started to pour again, such as figure 1 As shown, the cooling shrinkage of the casting slab 10 in the secondary cooling chamber 7 is large, and the casting slab 10 is easily detached from the secondary cooling support roll 8. When the straight-point pull-leveling roller is straightened, the pull-leveler 9 is likely to slip and rotate abnormally, resulting in an accident of liquid surface overflow in the crystallizer 4 and reducing the success rate of heat exchange in the tundish

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