Method for quickly replacing tundish at low liquid level of medium thin plate blank continuous casting machine crystallizer

Abstract

The invention provides a method for quickly replacing a tundish at a low liquid level of a medium thin plate blank continuous casting machine crystallizer. The method comprises the following steps of: (1) reducing the tonnage of liquid steel in an old tundish to 20 tons and reducing the pull speed at the same time; (2) reducing the tonnage of the old tundish to 8 to 10 tons, switching a crystallizer liquid level control mode from an automatic control mode into a manual control mode, and closing a plug stick; (3) rising the old tundish to a high-level removal pouring position, and starting a new tundish to move to the pouring position; (4) pulling the liquid level in the crystallizer to a position 550mm away from the upper edge of a copper plate of the crystallizer, and stopping pulling and straightening; (5) moving the new tundish to the pouring position; (6) pouring until the tonnage of the tundish is 4 tons, performing high-flow pouring, adding protection slag, and performing pulling and straightening; (7) increasing the pull speed to 1.30 m / min, and changing the manual control mode into the automatic control mode; and (8) increasing the pull speed to a target pouring speed, thus finishing the replacement of the tundish.

Description

technical field [0001] The invention belongs to the field of steelmaking, and in particular relates to a technology for quickly replacing a tundish at a low liquid level in a crystallizer of a medium-thin slab continuous casting machine. Background technique [0002] In the process of continuous casting, in order to improve the operation rate of the continuous casting machine by increasing the number of continuous casting furnaces, the process of quickly replacing the tundish with high liquid level in the mold is usually adopted to avoid the accident of steel leakage at the joint. Because the mold thickness of medium and thin slab continuous casting machine is generally in the range of 80mm to 150mm, while the thickness of the mold of thicker slab continuous casting machine is ≥200mm, that is, the thickness of the mold of medium and thin slab continuous casting machine is smaller than that of thicker slab continuous casting The thickness of the machine crystallizer, when usi...

AI Technical Summary

Problems solved by technology

Because the mold thickness of medium and thin slab continuous casting machine is generally in the range of 80mm to 150mm, while the thickness of the mold of thicker slab continuous casting machine is ≥200mm, that is, the thickness of the mold of medium and thin slab continuous casting machine is smaller than that of thicker slab continuous casting The thickness of the machine crystallizer, when using the high liquid level quick replacement tundish process, during the process of inserting the submerged nozzle into the molten steel in the mold, the billet shell formed by the molten steel remaining in the mold is likely to collide with it or cannot be inserted due to the shrinkage of the billet shell. Leading to the failure of changing the bag, the success rate of changing the tundish is low