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Method for controlling content of N in bearing steel GCr15

A technology of bearing steel and N content, applied in the field of controlling N content in GCr15 bearing steel, can solve the problems of technological measures without N content, etc., and achieve the effects of improving cost performance and market competitiveness, reducing costs, saving energy and protecting the environment

Active Publication Date: 2016-03-02
武汉钢铁有限公司
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Problems solved by technology

The patent "a production method of high-clean high-carbon chromium bearing steel" (patent number: ZL200410025102.5) adopts a five-step process: ① select ingredients; ②) ≥ 30 tons of electric furnace primary molten steel; ③ ladle furnace refining Molten steel: argon blowing intensity 0.4MPa in the early stage, 0.3MPa in the later stage; material addition ≤ 8Kg / ton of steel; two-step aluminum feeding method precipitation deoxidation; add crystalline silicon powder and fluorite (containing calcium fluoride ≥ 98%) to the slag surface ④ Vacuum furnace treatment: vacuum degree ≤ 140Pa, 25min + bottom blowing argon and weak stirring for 15min; ⑤ Liquid steel mold casting under inert atmosphere, this patent is a conventional bearing steel production process, and does not specifically aim at reducing N in GCr15 steel Process measures of content

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  • Method for controlling content of N in bearing steel GCr15

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] Converter smelting and tapping volume is about 150t, continuous casting slab section size: 200×200mm;

[0039] Sampling analysis composition before converter tapping: [C]: 0.61%, [P]: 0.013%, [S]: 0.029%, [N]: 0.0032%;

[0040] Temperature measurement before tapping: 1600°C;

[0041] The amount of LF slag in ladle refining is about 1.8t. After heating and arcing, 60Kg of carbon powder is spread on the refining slag with a spade (weight ratio: 3.3%) to form foam slag, and the thickness of the slag is about 450mm; : 1557°C; sampling analysis: [N]: 0.0052%;

[0042] The molten steel is vacuum treated in the RH furnace, the vacuum degree of the system is kept below 67Pa for 12 minutes, and the entire vacuum treatment time is 21 minutes; the soft Ar blowing time: 20 minutes, the Ar gas pressure: 0.26MPa, the flow rate: 125NL / min; sampling analysis: [N]: 0.0036%;

[0043] The long nozzle joint of the continuous casting ladle is sealed by spiral blowing Ar, and the Ar gas pre...

Embodiment 2

[0046] The electric furnace smelting and tapping volume are about 70t, and the cross-sectional size of the continuous casting slab is: 150×150mm;

[0047] Sampling analysis composition before electric furnace tapping: [C]: 0.70%, [P]: 0.007%, [S]: 0.021%, [N]: 0.0054%; temperature measurement before tapping: 1560℃;

[0048] The amount of LF slag in ladle refining is about 1.1t. After heating and arcing, 50Kg of carbon powder is spread on the refining slag with a spade (weight ratio: 4.5%) to form foam slag. The slag thickness is about 390mm; : 1545°C; sampling analysis: [N]: 0.0061%;

[0049] The molten steel is vacuum treated in the RH furnace, the vacuum degree of the system is kept below 67Pa for 20 minutes, and the entire vacuum treatment time is 25 minutes; the time of soft Ar blowing: 30 minutes, Ar gas pressure: 0.20MPa, flow rate: 100NL / min; sampling analysis: [N]: 0.0044%;

[0050] The long nozzle joint of the continuous casting ladle is sealed by spiral blowing Ar,...

Embodiment 3

[0053] Converter smelting and tapping volume is about 250t, continuous casting slab section size: 340×450mm;

[0054] Sampling analysis composition before tapping of converter: [C]: 0.40%, [P]: 0.016%, [S]: 0.024%, [N]: 0.0030%; temperature measurement before tapping: 1610℃;

[0055] The amount of LF slag in ladle refining is about 3.6t. After heating and arcing, spread 216Kg of carbon powder on the refining slag with a spade (weight ratio: 6.0%) to create foam slag with a thickness of about 500mm. Heating molten steel for 15 minutes, the temperature of molten steel : 1562°C; sampling analysis: [N]: 0.0052%;

[0056] The molten steel is vacuum treated in the RH furnace, the vacuum degree of the system is kept below 67Pa for 14 minutes, and the entire vacuum treatment time is 25 minutes; the time of soft Ar blowing: 25 minutes, Ar gas pressure: 0.28MPa, flow rate: 200NL / min; sampling analysis: [N]: 0.0041%;

[0057] The long nozzle joint of the continuous casting ladle is sea...

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Abstract

The invention discloses a method for controlling the content of N in bearing steel GCr15. The new technology of high-carbon and low-temperature tapping is adopted in the key tapping step; in the refining process, carbon powder is uniformly spread and added into a ladle furnace by a shovel, foaming slag is formed, and electrode submerged-arc heating is carried out; vacuum treatment and continuous casting protective casting are adopted. According to the method, N absorption is stopped and controlled in each processes of smelting of the bearing steel GCr15, the operation is simple, the energy is saved, the environment is protected, the cost is lowered, the cost performance and the market competitiveness of products are improved, and finally the content of N in the bearing steel GCr15 can be controlled to be smaller than or equal to 0.0050%.

Description

technical field [0001] The invention relates to the technical field of N content control in bearing steel in the steelmaking production process, and specifically refers to a method for controlling the N content in GCr15 bearing steel. Background technique [0002] The GB / T18254-2002 standard stipulates that high-carbon chromium bearing steels include: GCr4, GCr15, GCr15SiMn, GCr15SiMo, GCr18Mo, etc. 5 steel grades, the carbon content in the steel [C]: 0.95~1.05%, of which GCr15 is the representative steel type , which is mainly used to manufacture bearing rolling elements, inner and outer rings. The working conditions of bearings are extremely complicated, and they are subjected to various high alternating stresses, such as tension, pressure, shear and friction. Therefore, the bearing steel The material also puts forward very strict quality requirements. In order to ensure that the bearing steel has high fatigue strength, compressive strength, surface hardness and long servi...

Claims

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Application Information

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IPC IPC(8): C21C7/10C21C7/04C21C7/072
Inventor 陈庆丰陈佳杜方许竹桃李献忠张贤忠陈华强张渊普
Owner 武汉钢铁有限公司
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