Method for continuous casting of steel, and method for manufacturing bar steel

A casting billet and casting mold technology, applied in the field of steel bar manufacturing, can solve the problems of damaging the material properties of the steel bar, internal cracks in the casting billet, etc., and achieve the effects of reducing center segregation, improving productivity, and preventing center porosity

CN103764316AActive Publication Date: 2014-04-30NIPPON STEEL CORP
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2014-04-30

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Abstract

This method for continuous casting is provided with an extraction step for extracting a cast slab in a solid-liquid coexisting state from a cylindrical casting mold, a first rolling reduction step for performing rolling reduction of the cast slab in the solid-liquid coexisting state in a first rolling reduction direction perpendicular to the longitudinal direction of the cast slab after the extraction step, and a second rolling reduction step for molding the cast slab, in a completely solidified state in which the temperature of a center part thereof is higher than the temperature of a surface part thereof after the first rolling reduction step, into a rounded rectangle having rounded corner parts as viewed in cross-section perpendicular to the longitudinal direction of the cast slab, while performing rolling reduction alternately in the first rolling reduction direction and a second rolling reduction direction, the second rolling reduction direction being a rolling reduction direction orthogonal to both the first rolling reduction direction and the longitudinal direction of the cast slab.
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Description

technical field

[0001] The present invention relates to a continuous casting method for obtaining slabs (slabs) with excellent internal quality with less center segregation, less center porosity, and less internal cracks, and a method for manufacturing steel bars that can omit the blooming (block rolling) process.

[0002] This application claims priority based on Japanese Patent Application No. 2012-183179 for which it applied in Japan on August 22, 2012, and uses the content here. Background technique

[0003] Generally, high-grade (high-quality) steel bars are manufactured by casting a slab through a bloom continuous casting machine with a rectangular mold having a large cross-section, blooming the slab, and then casting steel sheet) rolling. The high-grade steel bar includes bar steel, wire rod and the like. In these steel bars, center segregation and center porosity formed at the end of solidification of the continuous casting slab lead to deterioration of material pr...

Examples

Embodiment 1

[0072]Through an example, the effect of one embodiment of the present invention will be described more specifically. However, the conditions in the Examples are an example of conditions adopted for confirming the feasibility and effects of the present invention, and the present invention is not limited to this example of conditions. Various conditions can be employed in the present invention as long as the object of the present invention is achieved without departing from the gist of the present invention.

[0073] Table 1 below shows cast steel types used in Examples. The steel type was set to two levels of A and B.

[0074] [Table 1]

[0075] steel type

C

Si

mn

P

S

Cr

Al

N

A

0.72

0.27

0.73

0.016

0.010

0.09

0.024

0.0040

B

0.15

0.24

0.73

0.015

0.011

1.00

0.025

0.0050

[0076] Each of the steels shown in Table 1 was drawn using a mold having an inner ...