High-quality steel for straight weather-resistant high-strength bolt and production method of high-quality steel

A technology of high-strength bolts and production methods, applied in the field of metallurgy, can solve the problems of steel subcutaneous inclusions, bolt cracks, etc., and achieve the effects of preventing surface cracks, improving impact value, and refining grains

Active Publication Date: 2021-11-19
HEBEI IRON AND STEEL
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The weather-resistant fastener steel produced in China is produced by converter refining, continuous casting and rolling long product process, often due to converter overoxidation, slag dropping during tapping, slag rolling during LF refining or vacuum refining process, and crystallizer pouring liquid level fluctuations Causes defects such as slag rolling and subcutaneous inclusions in the final steel, which cause bolts to crack during cold heading

Method used

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  • High-quality steel for straight weather-resistant high-strength bolt and production method of high-quality steel
  • High-quality steel for straight weather-resistant high-strength bolt and production method of high-quality steel

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Experimental program
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Effect test

Embodiment 1

[0023] The specification of fine steel for straight weather-resistant high-strength bolts in this embodiment is φ24mm, and its chemical composition and mass percentage are shown in Table 1.

[0024] The production method of high-quality steel for straight weather-resistant high-strength bolts in this embodiment includes the selection and treatment of raw materials, smelting, pouring, forging, and rolling processes. The specific process steps are as follows:

[0025] (1) Selection of raw materials and processing procedures: select pure iron with a grade of Fe99.5% as the main raw material, and add ferrosilicon, ferrochrome, and ferro-vanadium alloys to the alloys added during the smelting process after baking to 200°C;

[0026] (2) Smelting process: use a vacuum induction furnace to smelt, clean up the residue of the vacuum induction furnace crucible, add pure iron, check the airtightness of the vacuum furnace body, evacuate to 10Pa, send electricity to smelt and keep the vacuum...

Embodiment 2

[0032] The specification of fine steel for straight weather-resistant high-strength bolts in this embodiment is φ20mm, and its chemical composition and mass percentage are shown in Table 1.

[0033] The production method of high-quality steel for straight weather-resistant high-strength bolts in this embodiment includes the selection and treatment of raw materials, smelting, pouring, forging, and rolling processes. The specific process steps are as follows:

[0034] (1) Selection of raw materials and processing procedures: select pure iron containing Fe99.9% as the main raw material, and add ferrosilicon, ferrochrome, and ferro-vanadium alloys to the alloys added during the smelting process after baking to 270°C;

[0035] (2) Smelting process: use a vacuum induction furnace to smelt, clean up the residue of the vacuum induction furnace crucible, add pure iron, check the airtightness of the vacuum furnace body, evacuate to 10Pa, send electricity to smelt and keep the vacuum degr...

Embodiment 3

[0041] The specification of fine steel for straight weather-resistant high-strength bolts in this embodiment is φ27mm, and its chemical composition and mass percentage are shown in Table 1.

[0042] The production method of high-quality steel for straight weather-resistant high-strength bolts in this embodiment includes the selection and treatment of raw materials, smelting, pouring, forging, and rolling processes. The specific process steps are as follows:

[0043] (1) Selection of raw materials and processing procedures: select pure iron with a grade of Fe99.7% as the main raw material, and add ferrosilicon, ferrochrome, and ferrovanadium alloys to the alloys added during the smelting process after baking to 165°C;

[0044] (2) Smelting process: use a vacuum induction furnace to smelt, clean up the residue of the vacuum induction furnace crucible, add pure iron, check the airtightness of the vacuum furnace body, evacuate to 10Pa, send electricity to smelt and keep the vacuum ...

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Abstract

The invention discloses high-quality steel for a straight weather-resistant high-strength bolt and a production method of the high-quality steel. The high-quality steel comprises the following chemical components of, in percentage by mass, 0.18% to 0.24% of C, 0.13% to 0.28% of Si, 0.70% to 0.90% of Mn, P less than or equal to 0.010%, S less than or equal to 0.010%, 0.70% to 0.90% of Cr, 0.25% to 0.35% of Ni, 0.25% to 0.35% of Cu, 0.005% to 0.015% of Nb, 0.04% to 0.06% of V, 0.010% to 0.020% of Ti, 0.0010% to 0.0020% of B, H less than or equal to 1.5 ppm and the balance Fe and inevitable impurities. The production method comprises the working procedures of raw material selection and treatment, smelting, pouring, forging and rolling. Through component design and process innovation, the steel for the weather-resistant delayed-fracture-resistant high-strength bolt is developed to be used in cooperation with a bridge.

Description

technical field [0001] The invention belongs to the technical field of metallurgy, and in particular relates to a refined steel for straight weather-resistant high-strength bolts and a production method thereof. Background technique [0002] In recent years, with the rapid economic development of cities around the coast, many sea-crossing bridges have been built. At the same time, the demand for long-span bridge construction in alpine areas such as inland mountains and plateaus is also increasing. These areas often have high temperature, humidity and salinity all year round, and the environment is extremely harsh. Fastener bolts are easily corroded and broken in this environment for a long time, and there is a potential risk of bridge collapse. Therefore, there is an urgent need for domestic development of High-strength bolt steel with weather resistance and delayed fracture resistance is used in conjunction with bridges. [0003] In addition to the action of the pre-tighte...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/54C22C38/50C22C38/48C22C38/46C22C38/42C22C38/04C22C38/02C22C33/06C21D8/06
CPCC22C38/54C22C38/50C22C38/48C22C38/46C22C38/42C22C38/04C22C38/02C22C33/06C21D8/065Y02P10/20
Inventor 刘泳齐建军陈红卫张洪起赵海涛马超
Owner HEBEI IRON AND STEEL
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