Control method for improving internal defects of high-carbon chromium bearing steel bloom

A technology of high-carbon chromium bearing steel and control method, which is applied in the field of metallurgy, can solve problems such as compression cracks and center segregation, achieve the effects of reducing tensile stress, increasing force on the center, and achieving stabilization

Active Publication Date: 2019-12-03
XINGTAI IRON & STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The invention solves the problem of high-carbon chromium bearing steel by casting molten steel into large chamfered blooms with liquid cores, controlling continuous casting parameters, and implementing a soft reduction process for large chamfered billets with liquid cores. Internal defect problems such as cracks and center segregation under the billet

Method used

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  • Control method for improving internal defects of high-carbon chromium bearing steel bloom

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Effect test

Embodiment 1

[0037] In this embodiment, the control method for improving the internal defects of high-carbon chromium bearing steel blooms includes the following steps:

[0038] (1) Cast molten steel into a large chamfered bloom with a liquid core: the size of the continuous casting slab is 280×325mm, the angle between the corner of the continuous casting slab and the wide surface of the slab is controlled to be 30°, and the length of the hypotenuse of the continuous casting slab is 60mm ;

[0039] (2) Control continuous casting parameters: control the superheat of molten steel in the tundish to 15-25°C, the casting speed to 0.70m / min, the current intensity of electromagnetic stirring in the mold to 400A, and the frequency to 2.4Hz;

[0040] (3) Light reduction is carried out on the large chamfered bloom with liquid core, which is divided into two stages: dynamic reduction and static reduction:

[0041] a. In the stage of dynamic soft reduction, the reduction amount of a single reduction ...

Embodiment 2

[0050] In this embodiment, the control method for improving the internal defects of high-carbon chromium bearing steel blooms includes the following steps:

[0051] (1) Cast molten steel into a large chamfered bloom with a liquid core: the size of the continuous casting slab is 280×325mm, the angle between the corner of the continuous casting slab and the wide surface of the slab is controlled at 40°, and the length of the hypotenuse of the continuous casting slab is 45mm ;

[0052] (2) Control continuous casting parameters: control the superheat of molten steel in the tundish to 20-30°C, the casting speed to 0.85m / min, the current intensity of electromagnetic stirring in the mold to 500A, and the frequency to 1.2Hz;

[0053] (3) Light reduction is carried out on the large chamfered bloom with liquid core, which is divided into two stages: dynamic reduction and static reduction:

[0054] a. In the stage of dynamic soft reduction, the reduction amount of a single reduction rol...

Embodiment 3

[0063] In this embodiment, the control method for improving the internal defects of high-carbon chromium bearing steel blooms includes the following steps:

[0064] (1) Cast molten steel into a large chamfered bloom with a liquid core: the size of the continuous casting slab is 280×325mm, the angle between the corner of the continuous casting slab and the wide surface of the slab is controlled to be 32°, and the length of the hypotenuse of the continuous casting slab is 50mm ;

[0065] (2) Control continuous casting parameters: control the superheat of molten steel in the tundish to 18-23°C, the casting speed to 0.75m / min, the current intensity of electromagnetic stirring in the mold to 430A, and the frequency to 1.5Hz;

[0066] (3) Light reduction is carried out on the large chamfered bloom with liquid core, which is divided into two stages: dynamic reduction and static reduction:

[0067] a. In the stage of dynamic soft reduction, the reduction amount of a single reduction ...

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Abstract

The invention discloses a control method for improving internal defects of a high-carbon chromium bearing steel bloom. The control method comprises the steps that molten steel is cast into a large-chamfer bloom with a liquid core, continuous casting parameters are controlled, and a soft reduction process is carried out on the large-chamfer bloom with the liquid core. According to the method, the included angle between the corner of the continuous casting billet and the wide surface of the casting billet is controlled to be 30-40 degrees, and the length of the bevel edge is controlled to be 45-60 mm; the superheat degree of molten steel in the tundish is controlled to be 15-30 DEG C, and the casting speed is controlled to be 0.70-0.85 m/min; and dynamic soft reduction and static soft reduction are respectively carried out on the large-chamfer continuous casting billet with the liquid core. The internal defects of reduction cracks, center segregation and the like of the high-carbon chromium bearing steel bloom are overcome; the high-carbon chromium bearing steel bloom is subjected to macroscopic examination, the macroscopic examination comprises 0-0.5 grade of center porosity, 0.5-1.0 grade of center segregation, 0-0.5 grade of shrinkage cavity, 0-0.5 grade of middle cracks, 0-0.5 grade of center cracks and 55-68% of isometric crystal ratio; and the carbon segregation index of the center of the continuous casting billet is 0.95-1.06.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a control method for improving internal defects of high-carbon chromium bearing steel blooms. Background technique [0002] With the development and progress of continuous casting technology and the improvement of product quality requirements, the section size of billets tends to be larger. However, due to the inherent properties of solidification of various elements of molten steel, especially for high-carbon steel types, internal defects such as central segregation, porosity, and intermediate cracks are difficult to control, which has a great impact on product quality. [0003] In order to improve the internal defects of the continuous casting slab, the electromagnetic stirring technology, the low superheat pouring technology of the heating tundish, and the solidification end depression technology have been successively developed and successfully applied. The int...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22D11/16B22D11/18C22C38/02C22C38/04C22C38/28
CPCB22D11/16B22D11/18C22C38/002C22C38/02C22C38/04C22C38/28
Inventor 逯志方田新中董庆赵昊乾党爱国和红杰范振霞秦树超李敏王爱鑫赵彦岭王晓英
Owner XINGTAI IRON & STEEL
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