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Method for controlling decarburization on surfaces of medium-carbon cold forging steel wires

A technology of medium carbon cold heading steel and carbon cold heading steel, which is applied in the field of decarburization control of the surface layer of medium carbon cold heading steel wire rod, which can solve the problem of affecting the yield of cold heading steel, the reduction of service performance, the reduction of the strength and serviceability of cold heading steel Life and other issues, to achieve the effect of stable quality, low equipment requirements, and easy implementation

Inactive Publication Date: 2013-01-30
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The quality of the surface layer of cold heading steel has a great influence on its performance. The presence of decarburization on the surface will seriously reduce the strength and service life of cold heading steel, and at the same time seriously affect the yield of cold heading steel
When there is a certain thickness of decarburization layer on the surface of cold heading steel, the performance will be reduced

Method used

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  • Method for controlling decarburization on surfaces of medium-carbon cold forging steel wires
  • Method for controlling decarburization on surfaces of medium-carbon cold forging steel wires

Examples

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Embodiment 1

[0031] This embodiment is a method for controlling decarburization of the surface layer of medium-carbon cold heading steel wire. The chemical composition of medium-carbon cold heading steel wire is: C: 0.35%, Mn: 0.63%, Si: 0.22%, Cr: 0.97 %, Mo: 0.16%, P: 0.011%, S: 0.002%, Cu: 0.07%, Ni: 0.05%, Alt: 0.026%, and the balance is Fe and unavoidable impurities.

[0032] The carbon cold heading steel process route in this example is: electric furnace smelting→refining→continuous casting→slab shot blasting, grinding→slab heating→descaler→rough rolling→medium rolling→finish rolling→spinning→Steyr Wind chilling line→roll collection→binding and labeling→inspection→storage.

[0033] This embodiment is a continuous casting slab with a cross-sectional size of 150mm×150mm, rolling a cold heading steel wire rod with a diameter of 8mm, and the control method for decarburization on the surface of the wire rod is as follows:

[0034] Heating furnace heating process: In order to reduce the t...

Embodiment 2

[0039] This embodiment is a method for controlling decarburization of the surface layer of medium carbon cold heading steel wire. The chemical composition of medium carbon cold heading steel wire is: C: 0.35%, Mn: 0.65%, Si: 0.25%, Cr: 0.98 %, Mo: 0.17%, P: 0.019%, S: 0.006%, Cu: 0.08%, Ni: 0.04%, Alt: 0.031%, and the balance is Fe and unavoidable impurities.

[0040] The carbon cold heading steel process route in this example is: electric furnace smelting→refining→continuous casting→slab shot blasting, grinding→slab heating→descaler→rough rolling→medium rolling→finish rolling→spinning→Steyr Wind chilling line→roll collection→binding and labeling→inspection→storage.

[0041] This embodiment is a continuous casting slab with a cross-sectional size of 150mm×150mm, rolling a cold heading steel wire rod with a diameter of 13mm, and the control method for decarburization on the surface of the wire rod is as follows:

[0042]Heating furnace heating process: In order to reduce the t...

Embodiment 3

[0047] This embodiment is a method for controlling the decarburization of the surface layer of medium carbon cold heading steel wire. The chemical composition of medium carbon cold heading steel wire is: C: 0.34%, Mn: 0.64%, Si: 0.26%, Cr: 0.97 %, Mo: 0.18%, P: 0.019%, S: 0.006%, Cu: 0.08%, Ni: 0.04%, Alt: 0.029%, and the balance is Fe and unavoidable impurities.

[0048] The carbon cold heading steel process route in this example is: electric furnace smelting→refining→continuous casting→slab shot blasting, grinding→slab heating→descaler→rough rolling→medium rolling→finish rolling→spinning→Steyr Wind chilling line→roll collection→binding and labeling→inspection→storage.

[0049] This embodiment is a continuous casting slab with a cross-sectional size of 150mm×150mm, rolling a cold heading steel wire rod with a diameter of 10mm, and the control method for decarburization on the surface of the wire rod is as follows:

[0050] Heating furnace heating process: In order to reduce ...

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Abstract

The invention relates to a method for controlling decarburization on surfaces of medium-carbon cold forging steel wires. Cold forging steel comprises the following chemical ingredients in percentage by weight: 0.25 to 0.45 percent of C, 0.45 to 0.90 percent of Mn, 0.05 to 0.40 percent of Si, 0.70 to 1.50 percent of Cr, 0.03 to 0.50 percent of Mo, 0.015 to 0.045 percent of Alt and the balance of Fe and inevitable impurities. According to a process, the temperature of a first section of a heating furnace is 880 to 950 DEG C, the temperature of a second section is 980 to 1,050 DEG C, and the furnace temperature of a soaking section is 1,050 to 1,150 DEG C; the warmup time in the furnace is 90 to 130 minutes, and an air-fuel ratio of the soaking section is about 0.8:1; and the wire spraying temperature is 800 to 820 DEG C, and sprayed wires are cooled quickly at the cooling speed of 8 DEG C / second to the temperature of about 650 DEG C. By the method, fully-decarburized layers on the surfaces of the cold forging steel wires can be avoided, and the thicknesses of locally-decarburized layers are not more than 20 micrometers.

Description

technical field [0001] The invention belongs to the technical field of cold heading steel production, in particular to a method for controlling surface decarburization of medium carbon cold heading steel wire rods. Background technique [0002] Fasteners are very important mechanical parts and have been widely used in national defense, industry, agriculture, technology and daily life. The production level and quality performance of fasteners play a very important role in the development of automobile, machinery, aerospace and other industrial sectors; and cold heading steel is the raw material for fastener production. The automobile and machinery manufacturing industries are the main users of cold heading steel. In recent years, with the reduction in weight and performance of automobiles, there has been an urgent need to improve the strength and performance of cold heading steels. According to the forecast of the my country Association of Automobile Manufacturers, based on...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D8/06C21D11/00C22C38/22
Inventor 李恒坤吴年春尹雨群崔强王晓文
Owner NANJING IRON & STEEL CO LTD