Phosphorus-containing steel slab continuous casting method

Abstract

The invention provides a phosphorus-containing steel slab continuous casting method, wherein the phosphorus content of molten steel is equal to or greater than 0.02%. The phosphorus-containing steel slab continuous casting method comprises the following steps: carrying out low superheat degree control on molten steel, wherein the superheat degree range of molten steel in a tundish is 15-25 DEG C;adopting strong cooling for cooling a crystallizer, wherein the water flow velocity of the wide face of the crystallizer is 9.5-10.5 m / min, and the water flow velocity of the narrow face of the crystallizer is 13.0-14.0 m / min; carrying out deviation control on a plurality of continuous casting machine roll gaps in a sector section, and carrying out deviation control on the roll gap precision of zero section to fourth sections according to the range of + / -0.5 mm; carrying out negative deviation control on the roll gap precision of fifth section to the section before soft reduction according tothe range of -0.5 mm to 0 mm; carrying out positive deviation control on the roll gap precision of the section subjected to soft reduction according to the range of 0.3+ / -0.3mm; and carrying out deviation control on the roll gap precision of the section after soft reduction according to the range of + / -0.5mm. With adoption of the phosphorus-containing steel slab continuous casting method, generation of segregation of p at a grain boundary is effectively reduced, generation of segregation of p at a casting blank center is also reduced and an excellent phosphorus-containing steel slab is obtained.

Description

technical field [0001] The invention belongs to the field of continuous steel casting in the metallurgical industry, in particular to a method for continuous casting of phosphorus-containing steel slabs. Background technique [0002] For steel grades with p (phosphorus) content ≥ 0.02%, p is prone to segregation between dendrites, and broken strips are likely to occur in the subsequent hot rolling and cold rolling processes. At the same time, high p content is also prone to slab segregation. In the late rolling process, the banding is more serious, and the p dendrite segregation and p slab center segregation seriously affect the improvement of product quality. [0003] The soft reduction process is one of the most effective means to control the segregation at the center of the slab. Its principle is to give extra pressure to the mushy area at the solidification end of the center of the slab to break the bridge of the grain boundary there, so that the concentration of the enr...

AI Technical Summary

Problems solved by technology

[0002] For steel grades with p (phosphorus) content ≥ 0.02%, p is prone to segregation between dendrites, and broken strips are likely to occur in the subsequent hot rolling and cold rolling processes. At the same time, high p content is also prone to slab segregation. In the late rolling process, the banding is more serious, and the p dendrite segregation and p slab center segregation seriously affect the improvement of product quality

[0003] The soft reduction process is one of the most effective means to control the segregation at the center of the slab. Its principle is to give extra pressure to the mushy area at the solidification end of the center of the slab to break the bridge of the grain boundary there, so that the concentration of the enriched solute elements The phase and liquid phase are reflowed and fed to improve defects such as center segregation and porosity. In order to solve the problem of slab center segregation, domestic and foreign enterprises adopt a light reduction method, which has a certain effect on solving slab segregation, but The effect of solving interdendritic segregation is not obvious

[0004] The traditional light reduction technology can no longer meet the requirements of high phosphorus steel. How to adjust the process parameters, control the center segregation, and control the dendrite segregation at the same time is the focus of research in this field.