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Method for controlling center porosity defect of bearing steel

A technology of center loosening and control method, which is applied in the direction of rolling mill control devices, metal rolling, manufacturing tools, etc., can solve the problems affecting the internal quality and service performance of bearing steel, high cooling intensity, large interface temperature gradient, etc., to improve the internal Effects of quality and performance, improvement of quality pass rate, and improvement of quality level

Inactive Publication Date: 2012-11-21
ANGANG STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Due to the long distance from the liquidus line to the solid phase of high-carbon chromium bearing steel, low-magnification structural defects are more likely to occur
Especially when the continuous casting production process is used to produce bearing steel, because the continuous casting production process has greater cooling intensity than die casting, and the interface temperature gradient is large, it is easy to cause the enrichment of dendrites, resulting in periodic and intermittent cracks in the center of the slab. Shrinkage cavity and central segregation, accompanied by central porosity and fine pores, directly affect the internal quality and performance of bearing steel, reduce the quality pass rate of bearing steel, and cause unqualified accidents
In order to prevent the looseness of the center of the bearing steel, the current measures are to control the number of continuous casting, improve the slag blocking effect, control the oxygen content of the steel, and carry out a series of technological means such as refining and top slag modification, which not only increases the production process, but also increases the control difficulty

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] 1. Continuous casting process control:

[0029] The secondary cooling water of continuous casting adopts a weak cooling system, and the specific water volume is controlled at 15m 3 / Ton of steel, the amount of compressed air and water allocated in each area is:

[0030] area Cooling water distribution ratio (%)Air supply (m 3 / h) Mold foot roller26100 Support the upper part of the guide23.5100 Support the lower part of the guide position16100 Arc section21.5200 Two arcs 13100

[0031] Using low superheat and low drawing speed, considering that low superheat and low drawing speed are prone to flocculation accidents, which is not conducive to continuous casting of multiple furnaces, so the superheat is controlled at 12℃ and the drawing speed is controlled at 0.54m / min.

[0032] 2. Tundish baking system:

[0033] The tundish is baked on a low fire for 5 hours and then automatically baked for 2 hours, and the maximum baking temperature reaches 1450°C.

[0034] 3. Electromagn...

Embodiment 2

[0043] 1. Continuous casting process control:

[0044] The secondary cooling water of continuous casting adopts a weak cooling system, and the specific water volume is controlled at 15m 3 Per ton of steel, the distribution amount of compressed air and water in each area is:

[0045] area Cooling water distribution ratio (%)Air supply (m 3 / h) Mold foot roller26100 Support the upper part of the guide23.5100 Support the lower part of the guide position16100 Arc section21.5200 Two arcs 13100

[0046] Using low superheat and low drawing speed, considering that low superheat and low drawing speed are prone to flocculation accidents, which is not conducive to continuous casting of multiple furnaces, so the superheat is controlled at 18℃ and the drawing speed is controlled at 0.56m / min.

[0047] 2. Tundish baking system:

[0048] The tundish is baked on a low fire for 3.5 hours and then automatically baked for 2.5 hours. The maximum baking temperature reaches 1460°C.

[0049] 3. Elect...

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PUM

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Abstract

The invention provides a method for controlling a center porosity defect of bearing steel. Continuous casting adopts a weak cold system and low superheat and low drawing speed, a tundish adopts soft fire and automatic baking, electromagnetic stirring current intensity and frequency of a crystallizer are controlled, the heating charging temperature is smaller than 850 DEG C, the temperature of a soaking zone ranges from 1200 DEG C to 1220 DEG C, the heating total time is larger than or equal to 5 hours, high reduction rolling is adopted, the first two rolling reduction is controlled between 70mm and 80mm, and finished products are piled in a mode that multiple tanks are continuously piled in each steel tanks. By means of the method, continuous casting of the bearing steel can be achieved, slag blocking and control of oxygen content of tapping in the smelting process of a converter are not needed, special top slag modification treatment is avoided when refining is performed, the problem of water port blockage caused by impurities of the bearing steel can be effectively avoided, quality level of macrostructures of the bearing steel is greatly improved, inherent quality and using performance of bearing steel are improved, and the quality qualified rate of the bearing steel is increased.

Description

Technical field [0001] The invention belongs to the field of iron and steel metallurgy technology, and in particular relates to a control method for preventing bearing steel from producing center loose defects. Background technique [0002] The use of bearing steel is mostly under the conditions of coexistence of various alternating loads such as tensile stress, shearing force and friction. Therefore, the bearing steel after rolling must have a high and uniform hardness, that is, the bearing steel used should have strict The uniformity of the microstructure, especially the degree of segregation of carbon, sulfur, and phosphorus in the macro and microstructures, and the uniformity of the size, spacing and morphological distribution of precipitated carbide particles, so that the quality of the low-magnification structure of bearing steel puts forward higher requirements. [0003] Due to the long distance from the liquidus line to the solid phase of high carbon chromium bearing steel,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21B1/46B22D11/16B21B37/00
Inventor 王宁臧绍双罗建华曹维华李阳
Owner ANGANG STEEL CO LTD
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