Method for improving central carbon segregation of tire cord steel

A cord steel and carbon segregation technology, which is applied in the field of iron and steel metallurgy and processing, can solve problems such as steel cord drawing fracture, achieve the effect of improving central carbon segregation, and strong versatility of equipment and processes

Inactive Publication Date: 2010-07-14
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Aiming at problems such as steel cord pull-out fracture caused by excessive carbon segregation or serious carbon segregation resulting in the appearance of network carbides and martensite, the purpose of the present invention is to provide a method for improving carbon segregation in the center of cord steel. Methods

Method used

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Examples

Experimental program
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Effect test

Embodiment 1

[0020] A method for improving carbon segregation in the center of cord steel, the method adopts the technological process of primary smelting in an electric furnace, refining, continuous casting of blooms, rolling of billets, and rolling of billets into wire rods to produce 80-grade cord steel; The segregation of the finished cord steel hot-rolled wire rod is not greater than 0.5 grade, which meets the control requirements of cord steel users for central carbon segregation. The specific steps are as follows;

[0021] (1) Tapping process and carburizing process after tapping Ladle bottom blowing argon strong stirring (450L / min, 10.0bar), carburizing 0.5%. Strong stirring for 10 minutes followed by soft stirring (100L / min, 3.5bar) until refining accepts the ladle.

[0022] (2) When LF is refined, it is first alloyed and then carburized. Before adjusting the target carbon, the temperature is 1540°C.

[0023] (3) The superheat of continuous casting is 20°C, using full-protection ...

Embodiment 2

[0026] Yet another method for improving carbon segregation in the center of cord steel. The method adopts the process of primary smelting in an electric furnace, refining, continuous casting of blooms, rolling of billets, and rolling of billets into wire rods to produce 80-grade cord steel; The segregation of the hot-rolled wire rod of the finished cord steel product is not greater than 0.5, which meets the control requirements of the cord steel user for the central carbon segregation. The specific steps are as follows;

[0027] (1) Tapping process and carburizing process after tapping Ladle bottom blowing argon strong stirring (500L / min, 9.5bar), carburizing 0.6%. Strong stirring for 10 minutes followed by soft stirring (150L / min, 4.0bar) until refining accepts the ladle.

[0028] (2) When LF is refined, it is first alloyed and then carburized. Before adjusting the target carbon, the temperature is 1545°C.

[0029] (3) The superheat of continuous casting is 25°C, using full-...

Embodiment 3

[0032] Yet another method for improving carbon segregation in the center of cord steel. The method adopts the process of primary smelting in an electric furnace, refining, continuous casting of blooms, rolling of billets, and rolling of billets into wire rods to produce 80-grade cord steel; The segregation of the hot-rolled wire rod of the finished cord steel product is not greater than 0.5, which meets the control requirements of the cord steel user for the central carbon segregation. The specific steps are as follows;

[0033] (1) Tapping process and carburizing process after tapping Ladle bottom blowing argon strong stirring (600L / min, 9.0bar), carburizing 0.6%. Strong stirring for 10 minutes followed by soft stirring (200L / min, 3.5bar) until refining accepts the ladle.

[0034] (2) When LF is refined, it is first alloyed and then carburized. Before adjusting the target carbon, the temperature is 1555°C.

[0035] (3) The superheat of continuous casting is 30°C, using full-...

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Abstract

The invention discloses a method for improving the central carbon segregation in tire cord steel. The method produces 80 grade tire cord steel by adopting technical processes of electric furnace primary melting, refining, bloom concasting, billet rolling and rolled steel wire rolling by the billet, adopts control measures on each process, ensures strong stirring in argon blowing on the steel ladle bottom in a tapping process and a carbureting process after tapping; and the carburetion is controlled to be between 0.4 and 0.6 percent. Strong stirring is turned to be soft stirring after 10 minutes, until refining accepts the steel ladle. Alloying and carburetion are performed in sequence in LF refining, before aim carbon is adjusted, the temperature is ensured to be higher than 1,525 DEG C. In the method, the superheat degree of continuous casting is at 15 to 35 DEG C, full protection casting is adopted, a crystallizer is used for electromagnetic stirring, and the concasting bloom adopts soft press, so that the central carbon segregation of the tire cord steel is greatly improved, the hot-rolled rolled steel wire segregation of a tire cord steel finished product is not higher than 0.5 grade, and the control requirement of a tire cord steel user on the central carbon segregation can be met.

Description

technical field [0001] The invention belongs to the field of iron and steel metallurgy and processing, and specifically relates to a method for improving carbon segregation in the center of cord steel by adopting a control method in the process of electric furnace primary smelting, refining, continuous casting and steel rolling. Background technique [0002] The cord steel is high-carbon steel with a carbon content greater than 0.7%, and is widely used in steel cords for tire reinforcement. Due to the high carbon content of cord steel, central carbon segregation has become one of the main problems in technical quality control. Because during the solidification process of the slab, fine equiaxed crystals are formed on the surface due to chilling. As the solidification thickness of the surface layer increases, the heat transfer capacity inside the slab decreases, and the slab begins to solidify directionally, forming columnar crystals. Due to the separation and crystallizatio...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/00C21C7/072B22D11/16
Inventor 于小方郑建强李玉华刘宏玉
Owner NANJING IRON & STEEL CO LTD
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