Method for controlling narrow face bulging of thick continuous casting slab

Abstract

The invention provides a method for controlling narrow face bulging of all steel grades of thick continuous casting slabs with the thickness above 320mm. The method is characterized in that: a narrow face of the continuous casting slab is subjected to spraying cooling-water in the range of 4-8m below the foot roll part of a continuous casting machine, a used nozzle is in a vapor cooling type, the spraying angle of the nozzle is 80-110 degrees, a distance between the nozzle and the narrow face of the continuous casting slab is 160-350mm, and the water spraying volume is 8-20m<3> / h. Meanwhile, the inverted conicity of a copper plate on the narrow face of a crystallizer is controlled between 1.05 percent and 1.20 percent. By adopting the invention, the effective control both to narrow face bulging of the thick continuous casting slab with the thickness above 320mm and wide face deviation corner depression and longitudinal cracks caused by the narrow face bulging can be realized.

Description

technical field [0001] The invention relates to a control method for continuous casting thick slab narrow face belly, and belongs to the technical field of continuous steel casting in the metallurgical industry. Background technique [0002] With the continuous development of slab continuous casting technology, the thickness of continuous casting slabs is getting larger and larger. At present, the maximum thickness of domestic continuous casting slabs has reached 400mm. The maximum thickness of castable slabs reaches 600mm. With the continuous increase of the thickness of the continuous casting slab, the problem of bulging of the narrow surface of the continuous casting slab has become increasingly prominent. The bulging of the narrow side of the continuous casting slab often causes defects such as depressions deviated from the corners of the wide side, surface and subcutaneous longitudinal cracks, etc., so that the continuous casting slab has to be cleaned before it is sen...

AI Technical Summary

Problems solved by technology

The bulging of the narrow face of the continuous casting slab often causes defects such as depressions deviated from the corners of the wide face, surface and subcutaneous longitudinal cracks, etc., so that the continuous casting slab has to be cleaned before it is sent to the rolling workshop, resulting in an increase in production costs and reduction in production efficiency

What's more, when the surface longitudinal cracks caused by the bulging of the narrow surface are serious, it will also cause cracks and breakouts that deviate from the corners, thus affecting normal production

[0003] At present, the method usually adopted by continuous casting slabs to solve the bulging of the narrow surface of the continuous casting slab is to increase the taper of the copper plate on the narrow surface of the crystallizer and reduce the casting speed of the continuous casting slab. This method is effective for continuous casting slabs with a thickness of 300mm and below. However, it also brings new problems: the service life of the copper plate on the narrow side of the crystallizer is reduced due to increased wear, and the decrease in casting speed also leads to a decrease in the production capacity of the continuous casting machine

Moreover, for continuous casting slabs with a thickness greater than 300 mm, since the thickness of the continuous casting slab is relatively large, and the narrow surface of the continuous casting slab below the foot roll has neither mechanical support nor water cooling, even if the above method is adopted, the narrow slab cannot be completely eliminated. Belly defect

[0004] Chinese patent CN101683685A discloses a micro-alloyed wide-thick slab continuous casting technology, but the maximum thickness of the continuous casting slab is only 310mm, and it is limited to micro-alloyed steel. The content and pulling speed are limited, resulting in a relatively narrow scope of application