Manufacturing method of high-quality cold heading steel with uniform structure property

A technology of structure performance and manufacturing method, applied in the field of medium carbon cold heading steel wire rod production, can solve the problems of low processing rate, uneven structure of wire rod, cracking during cold heading processing, etc., so as to improve the qualification rate and reduce the problem of cold heading cracking. , the effect of improving economic efficiency

Active Publication Date: 2012-07-11
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The structure of the wire rod is uneven, and the mechanical properties are also different; this brings great inconvenience to the processing and use of downstream customers, resulting in problems such as cracking and low processing rate in cold heading processing

Method used

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  • Manufacturing method of high-quality cold heading steel with uniform structure property
  • Manufacturing method of high-quality cold heading steel with uniform structure property
  • Manufacturing method of high-quality cold heading steel with uniform structure property

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Example 1 uses a billet with a cross-section of 150×150mm, the finished product specification is Φ8mm, and the composition is shown in Table 1. The temperature of the billet out of the furnace is 1060°C, and the spinning temperature is 825°C. The rolling process and Stelmore air cooling The controlled cooling process is shown in Table 2, and the mechanical properties are shown in Table 3.

Embodiment 2

[0027] Example 2 uses a billet with a cross-section of 150×150mm, the finished product specification is Φ12mm, and the composition is shown in Table 1. The billet temperature is 1050°C, and the spinning temperature is 820°C. The controlled cooling process is shown in Table 2, and the mechanical properties are shown in Table 3.

[0028] Table 1 Chemical composition (wt, %)

[0029] Element C mn Si Cr P S Cu Ni Mo Alt Example 1 0.35 0.63 0.22 0.97 0.011 0.002 0.07 0.05 0.16 0.026 Example 2 0.35 0.65 0.25 0.98 0.019 0.006 0.08 0.04 0.17 0.031

[0030] In Table 1, except for the ingredients listed in the table, the rest are Fe and trace impurity elements.

[0031] Table 2 Controlled rolling and controlled cooling process

[0032]

[0033] "Middle" in Table 2 means "non-lap point".

[0034] Table 3 Mechanical Properties

[0035] Tensile strength MPa Elongation% rate of reduction in area% Vickers h...

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Abstract

The invention belongs to the technical field of medium carbon cold heading steel wire production, and relates to a manufacturing method of high-quality cold heading steel with a uniform structure property. The cold heading steel comprises the following chemical compositions by weight percent: 0.25 to 0.45% of C, 0.45 to 0.9% of Mn, 0.05 to 0.40% of Si, 0.70 to 1.50% of Cr, 0.03 to 0.50% of Mo, 0.015 to 0.045% of Alt, and the balance being Fe and unavoidable impurities. In a rolling process, a casting blank is heated, the billet taping temperature is 900 to 1150 DEG C, the final finish rolling temperature is 700 to 860 DEG C, and the spinning temperature is 800 to 880 DEG C. In a Stelmor air-cooled wire controlled cooling process, the casting blank is cooled to 500 to 700 DEG C at a cooling rate of more than 5 DEG C/s and then enters a cover, and the cooling rate in the cover is 0.2 to 0.8 DEG C/s. According to the manufacturing method, the traditional controlled rolling and controlled cooling process is reasonably set, and the role of the controlled rolling and controlled cooling process in structure control is fully played, so that the ideal structure is controlled, the cracking problem of the cold heading steel is greatly solved, the pass rate of standard finished products is improved, and the economic efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of production of medium-carbon cold heading steel wire rods, in particular to a method for manufacturing high-quality cold heading steel with uniform structure and properties. Background technique [0002] According to the forecast of the my country Association of Automobile Manufacturers, based on the development of complete vehicles during the "Twelfth Five-Year Plan" period far ahead of automotive fasteners, the next five years will be a period of rapid development of automotive fasteners. Due to the advantages of imported materials such as good hardenability, high purity and stable assembly, the high-grade fastener market has long been occupied by foreign products. [0003] In domestic steel enterprises, in the production of wire rods with ferrite and pearlite as the main structure, the cooling speed of lap joints and non-lap joints is not uniform during the cooling process. Non-lapping points: Ferrite ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/22C22C38/44C21D8/00
Inventor 李恒坤吴年春尹雨群王晓文
Owner NANJING IRON & STEEL CO LTD
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