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Heat treatment technique for bolts

A bolt and process technology, applied in the field of heat treatment of bolts, can solve problems such as insufficient hardness in the quenched state, uneven hardness in the quenched state, decarburization of the bolt surface, etc., and achieve the effects of good quenching effect, improved quality, and easy operation

Inactive Publication Date: 2017-12-05
JIANGSU YONGHAO HIGH STRENGTH BOLT
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the process of quenching and tempering heat treatment, some oxidizing gas is generally brought in from outside the furnace, and the oxidizing gas will react with the bolts, resulting in decarburization on the surface of the bolts. Due to the difference between the surface layer and the internal structure, they have different expansion coefficients, which may occur during quenching. Produce surface cracks and reduce product quality
The traditional heat treatment process is to directly put the bolts into the quenching furnace for high-temperature quenching. During the tempering and quenching process, problems such as insufficient quenched hardness, uneven quenched hardness, out-of-tolerance quenching deformation, and quenching cracks are prone to occur.

Method used

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  • Heat treatment technique for bolts

Examples

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Effect test

Embodiment 1

[0022] The heat treatment process of bolts includes the following steps:

[0023] S1. Phosphorus removal: Put the product into the washing machine and pour the cleaning solution until the product is completely immersed in the cleaning solution. Adjust the cleaning temperature to 40°C and stir once every 15 minutes. After cleaning for 2 hours, take the product out and put it away. Dephosphorization treatment is carried out in the dephosphorization tank;

[0024] The cleaning solution is composed of the following components in parts by mass: 20 parts of butyl acetate, 10 parts of polyglycolic acid, 16 parts of aminoacetic acid, 13 parts of ethyl acrylate, 5 parts of oleic acid triethanolamine salt, 3 parts of ethanolamine and 18 parts of water; The dephosphorization tank is equipped with a dephosphorization solution, and the dephosphorization solution is a potassium hydroxide solution with a concentration of 2.2g / L;

[0025] S2. Pretreatment: put the product into the preheating...

Embodiment 2

[0032] The present embodiment is identical with the processing step in embodiment 1, and difference is specific processing condition, comprises the following steps:

[0033] S1. Dephosphorization: Put the product into the washing machine, and pour the cleaning solution until the product is completely immersed in the cleaning solution. Adjust the cleaning temperature to 50°C, stir once every 15 minutes, and take out the product after cleaning for 3 hours. Dephosphorization treatment is carried out in the dephosphorization tank;

[0034] The cleaning solution is composed of the following components in parts by mass: 36 parts of butyl acetate, 13 parts of polyglycolic acid, 20 parts of aminoacetic acid, 22 parts of ethyl acrylate, 9 parts of triethanolamine oleic acid, 16 parts of ethanolamine and 26 parts of water; The dephosphorization tank is equipped with a dephosphorization solution, and the dephosphorization solution is a potassium hydroxide solution with a concentration of...

Embodiment 3

[0042] The present embodiment is identical with the processing step in embodiment 1, and difference is specific processing condition, comprises the following steps:

[0043] S1. Dephosphorization: Put the product into the washing machine, and pour the cleaning solution until the product is completely immersed in the cleaning solution. Adjust the cleaning temperature to 45°C, stir once every 15 minutes, and take out the product after cleaning for 2.5 hours. Put it in the dephosphorization tank for dephosphorization treatment;

[0044] The cleaning solution is composed of the following components in parts by mass: 28 parts of butyl acetate, 12 parts of polyglycolic acid, 18 parts of aminoacetic acid, 18 parts of ethyl acrylate, 7 parts of triethanolamine oleic acid, 10 parts of ethanolamine and 22 parts of water; The dephosphorization tank is equipped with a dephosphorization solution, and the dephosphorization solution is a sodium hydroxide solution with a concentration of 4.5g...

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PUM

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Abstract

The invention discloses a bolt heat treatment process, which comprises the following steps: dephosphorization, pretreatment, quenching, oil cooling, degreasing and tempering steps. The heat treatment process of the bolts of the present invention has simple steps, easy operation, and good quenching effect. The air in the preheating furnace and the quenching furnace can be removed by introducing nitrogen gas, so as to avoid the oxidation reaction between oxygen and the product, thereby avoiding the occurrence of decarburization. The failure of threaded fasteners prolongs the service life of the product, and the staged heating and quenching treatment can make the quenching effect of the product better and improve the quality of the product.

Description

technical field [0001] The invention relates to the technical field of bolt production, in particular to a heat treatment process for bolts. Background technique [0002] High-strength fasteners must be quenched and tempered according to technical requirements. Heat treatment and quenching is to improve the comprehensive mechanical properties of fasteners to meet the tensile strength and yield ratio specified by the product. The heat treatment process is essential for high-strength fastening Components, especially its intrinsic quality, have a crucial influence. During quenching and tempering heat treatment, some oxidizing gas is generally brought in from the outside of the furnace, and the oxidizing gas will react with the bolts, resulting in decarburization on the surface of the bolts. Due to the difference between the surface layer and the internal structure, they have different expansion coefficients. During quenching, it is possible Produce surface cracks and reduce pr...

Claims

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Application Information

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IPC IPC(8): C21D1/18C21D1/74C21D9/00C23G1/02C23C8/20
CPCC21D1/18C21D1/74C21D9/0093C23C8/20C23G1/02
Inventor 朱汉华
Owner JIANGSU YONGHAO HIGH STRENGTH BOLT
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