The Method of Reducing Casting Speed ​​and Increasing Success Rate of Quick Change in Billet Continuous Casting Machine

Abstract

The invention relates to the technical field of steelmaking, in particular to a method for reducing the casting speed of a billet continuous casting machine and increasing the success rate of quick change. The casting speed is reduced when the tundish is replaced, and the time for the billet to pass through the secondary cooling chamber is prolonged, thereby Increase the cooling intensity, and the temperature of the casting slab is lower before the quick-change casting speed returns to zero, so as to realize that the relative deformation of the casting slab staying in the second cooling chamber is smaller during the period from the quick-change drawing speed back to zero to the re-starting of casting, ensuring a new When the tundish is pouring, the slab can be pulled out of the mold normally under the current pressure of the straightening rollers, which avoids the occurrence of straightening cracks, improves the success rate of quick-change casting, ensures the quality of the slab, and is easy to operate; in addition, When the pouring is resumed, the connecting rod is used as the joint, so that the high-temperature molten steel flowing into the copper pipe of the crystallizer can absorb the heat of the molten steel after contacting the connecting rod, and realize that the molten steel solidifies while itself melting, thereby playing a connecting role , thereby avoiding the occurrence of steel breakout and ensuring the success of pouring.

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 billet continuous casting machine and improving 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. ...

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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