A method for quick change of different steel types in stainless steel continuous casting production

Abstract

The invention provides a method for rapid exchange of special steel balls in stainless steel continuous casting production. The method comprises the following steps that tundishes in different steel balls in 300 series steel balls are rapidly exchanged, and the width of the lower end of a crystallizer is adjusted online according to the cold blank widths and the billet shrinkage coefficient difference values of different steel balls before and after rapid exchange; the tundishes are sealed through inert gases, and the single-time rapid exchange time of the tundishes is shorter than or equal to 4 min; the density of previously-contained molten steel is larger than that of molten steel contained after rapid exchange, the temperature of the previously-contained molten steel is not lower than the set target temperature of the previous steel ball, and the temperature of the molten steel obtained after rapid exchange is not lower than the set target temperature of the rear steel ball. According to the method, the phenomenon of steel mixing during rapid exchange of the 300 series ordinary steel balls and the special stainless steel balls is improved and even eliminated, the continuous casting operation rate is increased, and crossed rapid exchange between the 300 series ordinary steel balls and the special stainless steel balls is achieved to a large degree; and the continuous casting time is shortened, sealing consumable consumption of the crystallizer is reduced, and the standby time spent on steel ball exchange is shortened.

Description

technical field [0001] The invention belongs to the field of steelmaking and relates to a method for quickly changing different steel types in stainless steel continuous casting production. Background technique [0002] The continuous casting process is a process in which liquid molten steel is poured, condensed, and cut through a ladle to obtain a slab. The most important link in this process is to continuously inject one or more furnaces of molten steel into the crystallizer through the ladle and the tundish. The formed crystallizer is water-cooled to obtain a billet with a solid billet shell around and liquid molten steel in the middle. Then the casting slab is gradually solidified through secondary cooling, and is pulled out of the continuous casting machine body through the support and rotation of the rollers in the tension-leveling device, and then cut into slabs of a certain length by the cutting device. Among them, the tundish, as the intermediate link between the l...

AI Technical Summary

Problems solved by technology

Among the 400 series steels, 409L has low high-temperature strength, and the expansion and contraction of the slab are too large, which is prone to deformation of the slab, which is stuck in the sector and cannot be pulled out. In addition, the molten steel temperature of 409L steel is too high and has high fluidity. It is easy to cause steel breakout, so 409L steel is not suitable for continuous casting with tundish quick change technology

The hardness of the 410 steel grade is too high. During the quick change, the molten steel in the crystallizer is too cooled, and it is difficult to correct the bending. It is also not allowed to participate in the quick change.

However, the quick change between 300 series ordinary and special steel grades is still in a blank stage. Therefore, it is imperative to find a tundish quick change technology suitable for 300 series special steel grades

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