Square bloom continuous casting manufacturing method facilitating elimination of core defects

Abstract

The invention provides a square bloom continuous casting manufacturing method facilitating elimination of core defects and belongs to the field of large-section square bloom production. According to the square bloom continuous casting manufacturing method, the continuous casting blank soft reduction technology and the hot core high-temperature heavy reduction rolling technology are optimized and combined. The core macrosegregation defects are eliminated in the soft reduction process; heavy-reduction rolling mills are directly arranged behind a continuous casting straightening and withdrawing machine, the online opposite reduction rolling process is implemented by making full use of cold outside and hot inside temperature field features of a casting blank under the complete solidification state of the casting blank to eliminate the defects such as core shrinkage cavity porosity.

Description

technical field [0001] The invention relates to the field of large-section billet production, specifically a high-quality casting billet production method that comprehensively utilizes continuous casting billet soft reduction technology and hot core high-temperature high-reduction rolling technology to carry out low macro segregation and shrinkage cavity defects . Background technique [0002] Usually, rolled products such as high-quality large cross-section bars are produced by hot rolling with blooms as raw materials, so the quality control of billets in continuous casting production plays a decisive role in the quality of final steel products. The main defects of the bloom are central shrinkage cavity, porosity and segregation, etc. If the defects in the core of the billet cannot be controlled in the continuous casting production and eliminated in the hot rolling production, central cracks and network and banded structure defects will occur , may have adverse effects on ...

AI Technical Summary

Problems solved by technology

The main defects of the bloom are central shrinkage cavity, porosity and segregation, etc. If the defects in the core of the billet cannot be controlled in the continuous casting production and eliminated in the hot rolling production, central cracks and network and banded structure defects will occur , may have adverse effects on the overall performance of the product, and even affect the safety of the product

Therefore, in conventional hot rolling production, a very large compression ratio is often required to eliminate these defects. Not only the process is long, the production cost is high, but also the finished product specifications of hot rolled products are limited.

[0003] Aiming at this common problem, soft reduction technology is often used in continuous casting production to solve the problem of segregation and shrinkage cavity in the core of the slab, that is, in the section of the solid phase ratio of the core of the slab 0.3-0.8, by a A group of rollers with a reduction function implements a multi-roller continuous small-reduction deformation with a reduction rate of about 3.0%. The application results have a certain effect on solving the segregation of the core of the slab, but the process has no effect on the core loose shrinkage defects. Elimination effect is not obvious

Furthermore, in recent years, the solidification end heavy reduction technology has appeared, aiming to apply a single-roll or multi-roll continuous large-deformation reduction process in the range of solid phase ratio of 0.8-1.0 in the core of the slab to solve the problem of shrinkage cavity and segregation in the core of the slab , but the material in this temperature range is in the low plasticity zone, and the flow and shrinkage ability of the steel material becomes poor. Therefore, under the action of large reduction deformation, cracks in the core of the slab are prone to occur and are retained in the slab product

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