High weather-resistant cold heading steel for 12.9-grade fasteners and production method thereof

A production method and fastener technology, which is applied in the field of cold heading steel production, can solve the problems of low strength of high weather resistance cold heading steel, and achieve the effects of increasing corrosion resistance, reducing costs, and strong adhesion

Active Publication Date: 2020-03-27
MAANSHAN IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] Aiming at the problem that the strength of existing high weather-resistant cold heading steel is not high, the present invention provides a high weather-resistant cold heading steel for 12.9 grade fas...

Method used

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  • High weather-resistant cold heading steel for 12.9-grade fasteners and production method thereof
  • High weather-resistant cold heading steel for 12.9-grade fasteners and production method thereof
  • High weather-resistant cold heading steel for 12.9-grade fasteners and production method thereof

Examples

Experimental program
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Effect test

Embodiment 1

[0087] The main chemical components and mass percentages of the high weather-resistant cold heading steel for grade 12.9 fasteners in this embodiment are shown in Example 1 in Table 1.

[0088] A production method of high weather-resistant cold heading steel for 12.9 grade fasteners of this embodiment includes the following steps on the basis of the ingredients of this embodiment:

[0089] S1. Electric furnace smelting; during the smelting process, the oxygen is fixed before tapping, and the steel is left during the tapping process to avoid slag.

[0090] S2, LF furnace refining: during the LF furnace refining process, adjust elements such as C, Si, Mn, Cr, Ni, Cu, V, Re, P to the target value.

[0091] S3, RH vacuum degassing; degassing time ≥ 15 minutes, [H] content ≤ 1.5ppm after vacuum treatment, to avoid hydrogen embrittlement of bolts.

[0092] S4. Billet continuous casting; the temperature of the molten steel in the tundish is controlled at 10-40°C above the liquidus l...

Embodiment 2

[0101] The main chemical composition and mass percentage of the high weather-resistant cold heading steel for 12.9-grade fasteners in this embodiment are shown in Example 2 in Table 1.

[0102] A production method of high weather-resistant cold heading steel for 12.9 grade fasteners of this embodiment includes the following steps on the basis of the ingredients of this embodiment:

[0103] S1. Electric furnace smelting; during the smelting process, the oxygen is fixed before tapping, and the steel is left during the tapping process to avoid slag.

[0104] S2, LF furnace refining: during the LF furnace refining process, adjust elements such as C, Si, Mn, Cr, Ni, Cu, V, Re, P to the target value.

[0105] S3, VD vacuum degassing; degassing time ≥ 15 minutes, [H] content ≤ 1.5ppm after vacuum treatment, to avoid hydrogen embrittlement of bolts.

[0106] S4. Billet continuous casting; the temperature of the molten steel in the tundish is controlled at 10-40°C above the liquidus l...

Embodiment 3

[0115] The main chemical composition and mass percentage of the high weather-resistant cold heading steel for 12.9-grade fasteners in this embodiment are shown in Example 3 in Table 1.

[0116] A production method of high weather-resistant cold heading steel for 12.9 grade fasteners of this embodiment includes the following steps on the basis of the ingredients of this embodiment:

[0117] S1. Converter smelting; during the smelting process, the oxygen is fixed before tapping, and the steel is left during the tapping process to avoid slag.

[0118] S2, LF furnace refining: during the LF furnace refining process, adjust elements such as C, Si, Mn, Cr, Ni, Cu, V, Re, P to the target value.

[0119] S3, RH vacuum degassing; degassing time ≥ 15 minutes, [H] content ≤ 1.5ppm after vacuum treatment, to avoid hydrogen embrittlement of bolts.

[0120] S4. Billet continuous casting; the temperature of the molten steel in the tundish is controlled at 10-40°C above the liquidus line, an...

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Abstract

The invention discloses high weather-resistant cold heading steel for 12.9-grade fasteners and a production method thereof, and belongs to the technical field of cold heading steel production. The high weather-resistant cold heading steel comprises the following chemical compositions of, by mass, 0.35%-0.45% of C, 0.30%-0.50% of Si, 0.60%-1.00% of Mn, 0.60%-0.83% of Cr, 0.50%-0.80% of Ni, 0.20%-0.40% of Cu, 0.05%-0.15% of Mo, 0.01%-0.06% of Ti, 0.015%-0.040% of Alt, 0.01%-0.10% of Re, 0.010%-0.030% of P, less than or equal to 0.0015% of O, less than or equal to 0.006% of N, and the balance Feand inevitable impurities. The tensile strength Rm is greater than or equal to 1220 MPa, the yield strength Rp0.2 is greater than or equal to 1100 MPa, the elongation after fracture A is greater thanor equal to 8%, the area shrinkage Z is greater than or equal to 44%, and the yield ratio is greater than or equal to 0.9, so that the performance requirements of the 12.9-grade cold heading steel aremet.

Description

technical field [0001] The invention belongs to the technical field of cold heading steel production, and more specifically relates to a high weather resistance cold heading steel for 12.9 grade fasteners and a production method thereof. Background technique [0002] Cold heading steel is mainly used for the production of fasteners such as bolts, screws, and nuts. my country's railway construction maintains rapid development. The new high-standard railways and the transformation of existing lines into high-speed EMUs, high-power locomotives, and heavy-duty trucks are the most urgent activities. Firmware provides new market demand, and the replacement of in-service equipment on railway lines also provides market space for fasteners. China has a vast territory and complex natural climate environment. With the development of rail transit, higher requirements are put forward for cold heading steel for fasteners. There is an urgent need to develop cold heading steel materials with...

Claims

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Application Information

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IPC IPC(8): C22C33/04C21D8/06C21D9/52C21D6/00C22C38/02C22C38/04C22C38/06C22C38/42C22C38/44C22C38/50B21B1/46B21B37/74
CPCB21B1/463B21B37/74C21D6/004C21D6/005C21D6/008C21D8/065C21D9/525C21D2211/002C21D2211/005C21D2211/009C22C33/04C22C38/001C22C38/002C22C38/005C22C38/02C22C38/04C22C38/06C22C38/42C22C38/44C22C38/50
Inventor 汪开忠姜婷于同仁郭湛张晓瑞龚梦强尹德福余良其丁雷孙凯吴建曦
Owner MAANSHAN IRON & STEEL CO LTD
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