High-strength atmospheric corrosion-resistant cold heading steel and preparation method thereof

A technology of atmospheric corrosion resistance and cold heading steel, which is applied in the field of cold forging steel to achieve the effects of improving delayed fracture resistance, improving atmospheric corrosion resistance, and reducing grain boundary segregation

Active Publication Date: 2018-12-18
RAILWAY ENG RES INST CHINA ACADEMY OF RAILWAY SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] Aiming at the problem that the strength and corrosion resistance of existing bolts need to be further improved, the p

Method used

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  • High-strength atmospheric corrosion-resistant cold heading steel and preparation method thereof

Examples

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Example Embodiment

[0049] Example 1

[0050] The embodiment of the present invention provides a high-strength atmospheric corrosion-resistant cold heading steel, the chemical composition of which is:

[0051] C 0.40%, Si 0.25%, Mn 0.90%, P 0.01%, S 0.002%, Cr 0.60%, Ni 0.20%, Cu 0.40%, Ti 0.020%, V0.10%, the balance is Fe and inevitable impurities .

[0052] The preparation steps of the above-mentioned high-strength atmospheric corrosion-resistant cold heading steel are as follows:

[0053] (1) Converter smelting: After the blast furnace hot metal is desulfurized, it is added to the combined blown converter for smelting, tapping to 3 / 20 of the total tapping volume, adding aluminum blocks, and tapping to 9 / 40 of the total tapping volume, adding sequentially Recarburizer, manganese silicon alloy, high-carbon ferromanganese, high-carbon ferrochrome, lime and refined synthetic slag;

[0054] (2) LF furnace refining: After LF enters the station, add 2.1kg / t lime, 1.3kg / t calcium carbide, 0.56kg / t aluminum pa...

Example Embodiment

[0058] Example 2

[0059] The embodiment of the present invention provides a high-strength atmospheric corrosion-resistant cold heading steel, the chemical composition of which is:

[0060] C 0.30%, Si 0.15%, Mn 0.60%, P 0.025%, S 0.010%, Cr 0.90%, Ni 0.50%, Cu 0.20%, Ti 0.040%, Mo 0.35%, Nb 0.005%, the balance is Fe and non Impurities to avoid.

[0061] The preparation steps of the above-mentioned high-strength atmospheric corrosion-resistant cold heading steel are as follows:

[0062] (1) Converter smelting: After the blast furnace hot metal is desulfurized, it is added to the combined blown converter for smelting, tapping to 1 / 8 of the total tapping volume, adding aluminum blocks, and tapping to 3 / 16 of the total tapping volume, adding sequentially Ferrosilicon alloy, recarburizer, high-carbon ferromanganese, high-carbon ferrochrome, lime and refined synthetic slag;

[0063] (2) LF furnace refining: After LF enters the station, add lime 2.5kg / t, 1.5kg / t calcium carbide, 0.7kg / t alu...

Example Embodiment

[0067] Example 3

[0068] The embodiment of the present invention provides a high-strength atmospheric corrosion-resistant cold heading steel, the chemical composition of which is:

[0069] C 0.28%, Si 0.30%, Mn 0.70%, P 0.008%, S 0.020%, Cr 0.80%, Ni 0.30%, Cu 0.30%, Ti 0.050%, Mo 0.15%, V 0.12%, the balance is Fe and Inevitable impurities.

[0070] The preparation steps of the above-mentioned high-strength atmospheric corrosion-resistant cold heading steel are as follows:

[0071] (1) Converter smelting: After the blast furnace hot metal is desulfurized, it is added to the combined blown converter for smelting, tapping to 3 / 20 of the total tapping volume, adding aluminum blocks, and adding when tapping to 1 / 4 of the total tapping volume. Ferrosilicon alloy, recarburizer, high-carbon ferromanganese, high-carbon ferrochrome, lime and refined synthetic slag;

[0072] (2) LF furnace refining: After LF enters the station, add 3.0kg / t lime, 1.75kg / t calcium carbide, 0.75kg / t aluminum part...

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Abstract

The invention relates to the technical field of cold heading steel, and particularly discloses high-strength atmospheric corrosion-resistant cold heading steel and a preparation method thereof. The high-strength atmospheric corrosion-resistant cold heading steel comprises, by weight, 0.28%-0.40% of C, 0.15%-0.30% of Si, 0.60%-0.90% of Mn, smaller than or equal to 0.025% of P, smaller than or equalto 0.020% of S, 0.60%-1.00% of Cr, 0.20%-0.50% of Ni, 0.20%-0.45% of Cu, 0.005%-0.050% of Ti, any one or more elements of 0.15%-0.35% of Mo, 0.09%-0.12% of V and 0.005%-0.015% of Nb, the balance Fe and unavoidable impurities. The cold heading steel prepared through the method has the high strength and hardness, has the good hardenability, meets the requirements of the hardenability of large-sizebolts, has the certain delayed fracture resistance, is low in production cost and has the characteristics of being good in corrosion resistance, high in tensile strength, good in surface quality and excellent in performance.

Description

Technical field [0001] The invention relates to the technical field of cold forging steel, in particular to a high-strength atmospheric corrosion-resistant cold-heading steel and a preparation method thereof. Background technique [0002] The connecting bolts used in railway, highway steel structure bridges and other facilities are high-strength bolts. Because they are in the field environment for a long time, the surface of the bolts and the surrounding medium (water vapor, salt, etc.) are prone to chemical and electrochemical interactions, resulting in corrosion. In particular, steel bridges generally span rivers, with high temperature and humidity throughout the year, and the environment is relatively harsh. The bolts are more likely to rust and corrode in this environment for a long time, which will eventually lead to fractures or cracks, forming a potential source of accidents. [0003] At present, the main measures to solve the corrosion problem are generally to increase the ...

Claims

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Application Information

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IPC IPC(8): C22C38/02C22C38/04C22C38/42C22C38/50C22C38/44C22C38/46C22C38/48C21D8/06C21C7/06C21C7/10
CPCC21C7/06C21C7/10C21D8/065C21D2211/005C21D2211/009C22C38/002C22C38/02C22C38/04C22C38/42C22C38/44C22C38/46C22C38/48C22C38/50
Inventor 王宁涛陶晓燕田新中董庆黄翠环李永超李宝秀阮士朋王利军孔维涛
Owner RAILWAY ENG RES INST CHINA ACADEMY OF RAILWAY SCI
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