Continuous casting stop-casting blank tail discharge and top sealing method

Abstract

The invention discloses a continuous casting stop-casting blank tail discharge and top sealing method. First and second stopper rods of a tundish of a two-machine and two-current continuous casting machine are opened; and first and second currents of molten steel flow into first and second crystallizers. When the height of the molten steel of the tundish is from 1130 mm to 680 mm, the continuous casting pull speeds of the first and second currents of molten steel in continuous casting are both reduced to 0.09-0.11 m / min at different accelerations; at this time, after the first and second stopper rods in the tundish are respectively closed, first and second blind plates are pushed in; first and second casting water ports are taken out from the first and second crystallizers; first and second cooling rods are put in the first and second crystallizers; and the continuous casting pull speeds are increased to 0.38-0.42 m / min for keeping by not shorter than 2 min. When the tail part of a continuous casting blank is discharged from lower ports of the crystallizers, and a foot roll section casting blank totally enters the tail part of the casting blank, the tail part of the casting blank is shrunk to form a recess area, and the tail discharge and the top sealing of the casting blank are finished. The top sealing method is excellent in tail discharge and top sealing of the casting blank, increases the molten steel yield, and has the popularization value.

Description

technical field [0001] The invention relates to a method for capping the end of the slab tail when the continuous casting of the continuous casting stop casting is used for preventing the overflow of the tail molten steel and good sealing of the tail of the slab when the continuous casting of molten steel is stopped in the continuous casting process of a metallurgical enterprise. Background technique [0002] The pouring process of continuous casting of molten steel in converter or electric furnace includes three main links: starting pouring, stable pouring, and tailing out after stopping pouring. Production accidents and slab quality problems are most likely to occur. Technicians in this technical field have always regarded the operation of starting and stopping (tailing out) as the focus of research, especially the capping of tailing out of the slab after continuous casting is a basic process operation when a casting is completed. During the tail-out process of the castin...

AI Technical Summary

Problems solved by technology

In addition, due to the low pulling speed at the end of the continuous casting slab and the high cooling intensity, the vibration marks of the slab are deep, and the vibration marks of the slab are further deepened during the high-frequency vibration of the mold, which deteriorates the surface quality of the slab

Under the condition of low casting speed (such as 0.2 ~ 0.3m / min) for a long time (such as more than 10min), the tail of the slab is severely overcooled (such as the surface temperature of the tail of the continuous casting slab is lower than 900 ℃), and transverse cracks occur. During the straightening process, the surface temperature of the slab drops to about 700°C (that is, in the third brittle temperature zone), and the surface of the slab is prone to straightening cracks (such as corner transverse cracks and surface transverse cracks). Being in the low-speed running zone for a long time, the solidified liquid state of the slab shrinks greatly, the acceleration of the slab tail exit is low (such as 0.25m / min 2 ), and the length of the tail layer is large. Only when the slab is trimmed to 1.5-2.0m can the tail delamination be avoided, otherwise the quality of the slab cannot be guaranteed, resulting in a great waste of slab and reducing the yield

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