Method for recooling large square billet during continuous casting tundish replacement

Abstract

The invention discloses a method for recooling a large square billet during continuous casting tundish replacement and belongs to the technical field of metallurgical production. The invention provides the method for recooling the large square billet during continuous casting tundish replacement, and the method can effectively guarantee the casting quality of the large square tail billet of a sectorial section in the process that the large square billet is continuously cast during on-line tundish replacement. The method for recooling the large square billet comprises the following steps of: during tundish replacement, recooling the large square tail billet of the sectorial section which is remained outside an outlet below a crystallizer after the crystallizer stops, wherein the large square tail billet of the sectorial section is recooled by five spray cooling areas; and the cooling intensity of the five spray cooling areas along the cooling direction is 45 to 61.5 L / (m<2>min), 8.2 to11.7 L / (m<2>min), 6.8 to 8.0 L / (m<2>min), 4.5 to 5.5 L / (m<2>min), and 1.4 to 2.0 L / (m<2>min) sequentially.

Description

technical field [0001] The invention relates to a secondary cooling method for a bloom, in particular to a secondary cooling method for a bloom in a continuous casting tundish during bag change, and belongs to the technical field of metallurgical production. Background technique [0002] During the bloom continuous casting process, due to the long liquid core of the billet, bridging is easily formed at the end of solidification, resulting in central loose defects, and in severe cases, shrinkage cavity defects. Therefore, the solidification characteristics of the bloom determine that the bloom is very prone to center porosity defects and shrinkage cavity defects. According to this feature, in order to improve the continuous casting quality of blooms, at present, major billet continuous casting manufacturers at home and abroad pay special attention to improving the uniformity of casting blank cooling in the process of continuous casting of blooms, so as to prevent and reduce t...

AI Technical Summary

Problems solved by technology

During this period of time, the large square tail billets located outside the lower outlet of the crystallizer are subjected to very strong cooling, and the cooling uniformity is poor. Therefore, compared with the bloom produced by the normal continuous casting process, it is easier to produce central shrinkage cavities, Defects such as center porosity and center cracks

At present, in domestic and foreign public documents, the control of the cooling speed of the bloomer billet in the process of changing the package of the bloom continuous casting adopts a method other than increasing the length of the waste cutting of the changing package of the large tail billet and minimizing the downtime. In general, there are two methods, one is to use the water volume at the minimum pulling speed of 0.2-0.3m / min, the cooling is still strong in this way; the other is to directly shut down the cooling water of the large square tail blank in the fan-shaped section Although this method ensures the uniform cooling of the slab in the sector, it does great damage to the casting machine equipment, and it is also easy to cause the large square tail billet breakout accident in the sector