A cold-heading steel wire rod for ultra-high-strength locking rivets and its preparation method

An ultra-high-strength, cold-heading steel technology, applied in the field of cold-heading steel wire rods for ultra-high-strength lock rivets and its preparation, can solve the problem that the delayed fracture resistance of wire rods cannot meet the production requirements of lock rivets, and the hardness is difficult to guarantee , unable to produce ultra-high-strength rivets and other issues

Active Publication Date: 2021-09-03
XINGTAI IRON & STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since the C content is the decisive element to determine the hardenability of the steel, the C content ranges from 0.16 to 0.24%, and it is difficult to ensure the hardness of the steel after quenching to be above 50HRC. When tempering, it is impossible to produce 530-580HV ultra-high-strength rivets
In addition, the delayed fracture resistance of the wire involved in this invention cannot meet the production requirements of lock rivets

Method used

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  • A cold-heading steel wire rod for ultra-high-strength locking rivets and its preparation method
  • A cold-heading steel wire rod for ultra-high-strength locking rivets and its preparation method
  • A cold-heading steel wire rod for ultra-high-strength locking rivets and its preparation method

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] The embodiment of the present invention provides a cold heading steel wire rod for ultra-high strength locking rivets, the composition of which is: C 0.33%, Mn 1.10%, Si 0.24%, P 0.020%, S 0.005%, Cr 0.30%, Nb 0.030%, Al 0.023%, Ti0.020%, B 0.0020%, and the rest are iron and unavoidable impurity elements.

[0039] The preparation steps of the cold heading steel wire rod for the above-mentioned ultra-high-strength locking rivets are as follows:

[0040] (1) The molten steel smelted by the converter is refined outside the LF furnace and then subjected to RH vacuum refining. The vacuum degree of the vacuum tank in the RH process is 70pa, and the pure degassing time of the RH refining is 20min. The molten steel refined by RH is prepared into a bloom through the continuous casting process.

[0041] (2) After blooming the bloom obtained in step (1), place the hot-rolled billet in a slow cooling pit for 48 hours;

[0042] (3) Steel slab heating: heat the hot-rolled slab after...

Embodiment 2

[0045] The embodiment of the present invention provides a cold heading steel wire rod for ultra-high strength locking rivets, the composition of which is: C 0.35%, Mn 0.95%, Si 0.17%, P 0.012%, S 0.010%, Cr 0.20%, Nb 0.020%, Al 0.041%, Ti0.027%, B 0.0022%, and the rest are iron and unavoidable impurity elements.

[0046] The preparation steps of the cold heading steel wire rod for the above-mentioned ultra-high-strength locking rivets are as follows:

[0047] (1) The molten steel smelted by the converter is refined outside the LF furnace and then subjected to RH vacuum refining. The vacuum degree of the vacuum tank in the RH process is 67pa, and the pure degassing time of the RH refining is 15 minutes. The molten steel refined by RH is prepared into a bloom through the continuous casting process.

[0048] (2) After blooming the bloom obtained in step (1), place the hot-rolled billet in a slow cooling pit for 49 hours;

[0049] (3) Steel slab heating: heat the hot-rolled slab ...

Embodiment 3

[0052] The embodiment of the present invention provides a cold heading steel wire rod for ultra-high strength locking rivets, the composition of which is: C 0.38%, Mn 0.87%, Si 0.01%, P 0.009%, S 0.008%, Cr 0.27%, Nb 0.035%, Al 0.033%, Ti0.034%, B 0.0010%, and the rest are iron and unavoidable impurity elements.

[0053] The preparation steps of the cold heading steel wire rod for the above-mentioned ultra-high-strength locking rivets are as follows:

[0054] (1) The molten steel smelted by the converter is refined outside the LF furnace and then subjected to RH vacuum refining. The vacuum degree of the vacuum tank in the RH process is 70pa, and the pure degassing time of the RH refining is 17 minutes. The molten steel refined by RH is prepared into a bloom through the continuous casting process.

[0055] (2) After the bloom obtained in step (1) is opened, the hot-rolled billet is placed in a slow cooling pit for 52 hours;

[0056] (3) Steel slab heating: heat the hot-rolled ...

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Abstract

The invention relates to the technical field of cold heading steel, and specifically discloses a cold heading steel wire rod for ultra-high strength locking rivets and a preparation method thereof. The weight percentage of the chemical composition of the cold heading steel wire rod is C 0.33-0.38%, Si ≤0.30%, Mn 0.80~1.10%, P≤0.020%, S≤0.020%, Cr 0.10~0.30%, Nb 0.010~0.050%, Ti 0.020~0.050%, Al 0.020~0.050%, B 0.0010~0.0035%, The rest is Fe and unavoidable impurity elements. During the preparation process, the hydrogen in the steel is removed by RH vacuum refining, and the hot-rolled billet is placed in the slow cooling pit to further reduce the hydrogen content. Through the control of heating and rolling processes, the obtained hot-rolled wire rod has easy spheroidizing annealing and good cold working Performance, good toughness and delayed fracture resistance after heat treatment.

Description

technical field [0001] The invention belongs to the field of wire rod production, and relates to a cold heading steel wire rod for ultra-high strength locking rivets and a preparation method thereof. Background technique [0002] Energy saving and environmental protection are major issues related to the sustainable development of human society. Reducing fuel consumption and exhaust emissions has become the focus of common attention in the development of the automotive industry. Reducing the weight of the car itself is one of the most effective measures to reduce fuel consumption and reduce exhaust emissions. One of the main ways to reduce the weight of the car body is to use lightweight materials. According to the current technology to achieve lightweight vehicles, the most effective way is to use aluminum instead of steel. Lock riveting (self-piercing riveting, SPR) technology is the key technology to realize the lightweight of automobiles, which opens up a new way for the...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/02C22C38/04C22C38/06C22C38/26C22C38/28C22C38/32C22C33/04C21D8/06
CPCC21D8/065C21D2211/005C21D2211/009C22C33/04C22C38/02C22C38/04C22C38/06C22C38/26C22C38/28C22C38/32
Inventor 王利军田新中董庆阮士朋李永超郭明仪王宁涛韩广杰张鹏马洪磊秦树超孔维涛张剑许利凯
Owner XINGTAI IRON & STEEL
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