Method for improving peritectic steel liquid level fluctuation of same-roll-diameter slab continuous casting machine

Abstract

The invention belongs to the technical field of metallurgy, and particularly relates to a method for improving peritectic steel liquid level fluctuation of a same-roll-diameter slab continuous casting machine, which comprises the steps of crystallizer cooling water optimization, fan-shaped section secondary cooling water optimization, peritectic steel grade carbon mass fraction optimization, crystallizer narrow surface reverse taper adjustment, fan-shaped section forward arc and driving roll equipment precision detection and the like. The liquid level fluctuation condition of a crystallizer during peritectic steel production of a casting machine is effectively improved, the liquid level fluctuation can be controlled to be within plus or minus 3mm from plus or minus 15mm, meanwhile, surface longitudinal cracks of peritectic steel can be effectively reduced, a great help effect is achieved on stable and smooth production of the casting machine, casting blank quality and connection of front and back procedures, and good popularization value is achieved.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a method for improving the liquid level fluctuation of peritectic steel in a slab continuous casting machine with the same roll diameter. Background technique [0002] Crystalline steel is an important series of steel grades for continuous casting, but due to the characteristics of its steel grades, when producing peritectic steel grades with a carbon mass fraction of 0.08% to 0.15%, peritectic phase transformation will occur during its solidification process. At this time, the air gap formed between the mold and the billet shell is the largest, resulting in uneven initial solidification of the billet. In addition, after the billet exits the mold, the rollers with the same roll diameter act on the "bulging" and the billet shell. On slabs with uneven thickness, the liquid core changes between each pair of rollers are synchronized, resulting in obvious liquid level f...

AI Technical Summary

Problems solved by technology

At this time, the air gap formed between the crystallizer and the billet shell is the largest, resulting in uneven initial solidification of the billet shell. In addition, after the cast billet leaves the mold, the rollers with the same roll diameter act on the "bulging" and the billet shell On the slab with uneven thickness, the change of the liquid core between each pair of rollers is carried out synchronously, resulting in obvious liquid level fluctuations

[0003] The No. 4 continuous casting machine of Shandong Iron and Steel Group Rizhao Co., Ltd. steelmaking plant designed a 200*2300mm section slab continuous casting machine for Danieli. Since the hot test was put into production in January 2019, the casting carbon mass fraction is 0.10% to 0.12%. For peritectic series steels, periodic severe liquid level fluctuations often occur in the crystallizer, and in severe cases, the liquid level fluctuation range can reach plus or minus 15mm; at the same time, due to the crystallizer liquid level fluctuations, the mold liquid level automatic control system It cannot be put into normal use, and the casting operation can only be performed by manually controlling the stopper rod, resulting in a large number of unsteady billets, which have a serious impact on the casting safety of the casting machine, the quality of the billets and the production organization of the process.