Method for decreasing decarburized layers on surfaces of high-carbon-chromium bearing steel wires

A technology of high-carbon chromium bearing steel and decarburization layer, which is applied in the field of bearing steel production, to achieve the effects of reducing cost, good composition uniformity, and reducing the amount of surface grinding

Inactive Publication Date: 2015-12-09
XINGTAI IRON & STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Patent No. CN03117411.6 announced "A Heating Method for Preventing Decarburization of High-Carbon

Method used

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  • Method for decreasing decarburized layers on surfaces of high-carbon-chromium bearing steel wires
  • Method for decreasing decarburized layers on surfaces of high-carbon-chromium bearing steel wires
  • Method for decreasing decarburized layers on surfaces of high-carbon-chromium bearing steel wires

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0030] The molten steel is smelted and continuously cast into a 325mm*280mm cross-section bloom, and its composition by weight percentage is: C1.0%, Si0.24%, Mn0.36%, Cr1.49%, P0.012%, S0.004%, Cu0.03%, Ni0.02% and the rest are iron and unavoidable impurity elements.

[0031] After the bloom is heated and diffused, it is opened into a hot-rolled billet with a cross-section of 160mm*160mm, and the surface of the hot-rolled billet is ground by 1mm.

[0032] The hot-rolled billet is heated in a heating furnace, the temperature of the preheating section is 800°C, the temperature of the heating section is 1040°C, the temperature of the soaking section is 1060°C, the residual oxygen content is 0.5%, and the time in the furnace is 100min.

[0033] After high-speed rolling, the steel billet is spun at 820°C. After spinning, the cooling rate is controlled at 8°C / s, rapidly cooled to below 600°C, and then slowly cooled.

[0034] The GCr15 bearing steel hot-rolled wire rod with a specif...

Embodiment 2

[0036] The molten steel is smelted and continuously cast into a 325mm*280mm cross-section bloom, and its composition by weight percentage is: C0.99%, Si0.23%, Mn0.35%, Cr1.50%, P0.010%, S0.003%, Cu0.03%, Ni0.02% and the rest are iron and unavoidable impurity elements.

[0037] After the bloom is heated and diffused, it is opened into a hot-rolled billet with a cross-section of 160mm*160mm, and the surface of the hot-rolled billet is ground by 1.5mm.

[0038] The hot-rolled billet is heated in a heating furnace, the temperature of the preheating section is 850°C, the temperature of the heating section is 1050°C, the temperature of the soaking section is 1070°C, the residual oxygen content is 0.6%, and the furnace time is 90min.

[0039] After high-speed rolling, the steel billet is spun at 840°C. After spinning, the cooling rate is controlled at 7°C / s, rapidly cooled to below 600°C, and then slowly cooled.

[0040] The GCr15 bearing steel hot-rolled wire rod with a specificati...

Embodiment 3

[0042] Melt steel is smelted and continuously cast into a 325mm*280mm section bloom, the composition of which is: C1.1%, Si0.24%, Mn0.37%, Cr1.47%, P0.013%, S0.002%, by weight percentage, Cu0.03%, Ni0.02% and the rest are iron and unavoidable impurity elements.

[0043] After the bloom is heated and diffused, it is opened into a hot-rolled billet with a section of 160mm*160mm, and the surface of the hot-rolled billet is ground by 2mm.

[0044] The hot-rolled billet is heated in a heating furnace, the temperature of the preheating section is 840°C, the temperature of the heating section is 1030°C, the temperature of the soaking section is 1060°C, the residual oxygen content is 0.5%, and the furnace time is 95min.

[0045] After high-speed rolling, the steel billet is spun at 850°C, and after spinning, it is rapidly cooled to below 600°C at a cooling rate of 6°C / s for slow cooling.

[0046] The GCr15 bearing steel hot-rolled wire rod with a specification of Φ20mm produced by th...

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Abstract

The invention relates to a method for decreasing decarburized layers on surfaces of high-carbon-chromium bearing steel wires. The specific process comprises the steps that steel is molten to obtain molten steel which is subjected to continuous casting to form bearing steel, the bearing steel is subjected to continuous casting to form a bloom, and the bloom is rolled into square hot rolling billet with the section being 160mm*160mm; the surface of the square hot rolling billet is ground, and the grinding amount is 0.5-2mm; the square hot rolling billet is heated in a heating furnace, micro positive pressure control is adopted in the furnace, the pressure in the furnace is 5-40 Pa, the weak oxidizing atmosphere is adopted in the furnace, and the air-fuel ratio is adjusted to enable the oxygen remaining volume in the furnace to be 0-2%; and the spinning temperature is controlled to be 800-850 DEG C, cooling is performed at the rate of 5-10 DEG C/s after spinning to reduce the temperature to 500-600 DEG C, and then slow cooling is performed to obtain hot-rolled wire rods. According to the bearing steel wires obtained through the method, the surfaces are free of fully decarburized layers, and the depth of half decarburized layers is smaller than 50 microns; meanwhile, good component uniformity and internal structure uniformity are achieved, and the product quality requirement of downstream customers can be met; besides, the surface grinding amount of the downstream customers can be reduced, the cost is lowered, and a certain competitive advantage is provided.

Description

technical field [0001] The invention belongs to the technical field of bearing steel production, and particularly relates to a method for reducing the decarburization layer on the surface of high-carbon chromium bearing steel wire rods. Background technique [0002] GCr15 bearing steel wire is mainly used to manufacture rolling elements of rolling bearings, such as steel balls and rollers. If the decarburization layer on the surface of the bearing steel wire is not well controlled, it will be inherited to the final steel ball or roller, causing soft spots on the surface of the rolling element after heat treatment, resulting in uneven hardness and early fatigue failure of the bearing. In order to eliminate soft spots, rolling element manufacturers have to increase the amount of grinding, which not only wastes materials but also increases production costs and production efficiency. Therefore, it is very necessary and meaningful to optimize the production process to control th...

Claims

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Application Information

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IPC IPC(8): C21D8/06C21D1/74
Inventor 阮士朋崔娟郭明仪刘振民张磊赵铮铮王伟戴永刚李宝秀李世琳李永超黄翠环
Owner XINGTAI IRON & STEEL
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