Bloom continuous casting dynamic soft reduction process for high-quality tire cord steel

Abstract

The invention relates to a bloom continuous casting dynamic soft reduction process for high-quality tire cord steel, belonging to the technical field of metallurgy continuous casting and used for solving the problems of internal quality defects of casting billets such as central segregation, central porosity, central contraction cavity and the like which are easy to occur in tire cord steel bloomcontinuous casting. The invention adopts the technical scheme that in a continuous casting soft reduction region, the reduction amount is controlled by the variation of casting billet central solid phase rate fs, and a quantitative relationship of the reduction amount of a soft reduction stand and the casting billet central solid phase rate is given. By adopting the dynamically controlled soft reduction process, the central segregation of tire cord steel casting billets can be remarkably lightened with the casting billets center carbon segregation index controlled between 0.96 to 1.05 and theaverage value of 1.03; and the central porosity and the central contraction cavity of the tire cord steel casting billets can also be remarkably improved with the casting billet central porosity of nomore than 1.0 level and the central pipe of no more than 0.5 level. The technical requirements for manufacturing the high-quality tire cord steel are satisfied by wires rolled by the processed continuous casting billets.

Description

technical field [0001] The invention relates to a continuous casting process, especially a high-quality cord steel bloom continuous casting dynamic soft reduction process that can eliminate or reduce bloom center segregation, center looseness, center shrinkage cavity and other internal quality defects of the billet, belonging to the metallurgical continuous casting process. casting technology field. Background technique [0002] Steel cords are mainly used in tire meridian reinforced skeletons, which have the characteristics of high strength and good toughness. There are many problems. Due to the large cross-sectional size of the billet cord steel billet and high carbon steel, it is easy to appear transverse and longitudinal cracks, star-shaped cracks, corner depressions, corner and subcutaneous large inclusions and internal Defects such as shrinkage cavity, center porosity, center segregation and internal cracks, among which center segregation, center porosity and center ...

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Problems solved by technology

[0005] Chinese patent 200710048924.9 discloses the dynamic light reduction process of continuous casting of heavy rail steel blooms. Although heavy rail steel and cord steel belong to high carbon steel, there are still differences in the carbon content of the two, especially the alloy elements and content of the two. They are all different, and they will lead to differences in high-temperature mechanical properties and solidification characteristics of steels, especially differences in the shape of the two-phase region, so they will eventually lead to differences in reduction efficiency and reduction amount.

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