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Production method of high-weather-resistance bolt

A production method and high weather resistance technology, applied in the field of bolt production, can solve the problems of poor wear resistance, failure to guarantee long-term corrosion resistance requirements of bolts, high weather resistance, etc., and achieve improved weather resistance, excellent industrial atmospheric corrosion resistance, and increased strength. Effect

Inactive Publication Date: 2020-08-25
ANHUI CHANGJIANG FASTENERS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the corrosion resistance, weather resistance and wear resistance of bolts are often a pair of contradictory considerations. Generally, the weather resistance is high, and the wear resistance is poor.
[0003] At present, the high-strength bolts used in infrastructure facilities such as steel structure bridges and electric towers are mainly grade 12.9. Due to the long-term corrosion-prone environment, ordinary high-strength bolts of grade 12.9 cannot meet the demand. Surface treatment, but this does not guarantee the long-term corrosion resistance requirements of the bolts, it still needs to be painted repeatedly or replace the bolts

Method used

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  • Production method of high-weather-resistance bolt
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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] A method for producing high-weather-resistant bolts, comprising the steps of:

[0024] S1, rolling the cast ingot into a billet with a diameter of 25mm, and then sequentially undergoing pickling, end face chamfering, flat head, head forming, and head chamfering to obtain a billet;

[0025] The chemical composition of the ingot includes by mass percentage: C: 0.28%, Si: 0.06%, Mn: 0.32%, Cr: 0.62%, Nb: 0.01%, Ni: 0.08%, Cu: 0.1%, V: 0.04%, Ti: 0.011%, Zr: 0.005%, Re: 0.001%, P≤0.002%, S≤0.002%, the balance is Fe and other unavoidable impurities;

[0026] S2, using a sodium hydroxide solution with a pH value of 8 to degrease the billet obtained in S1, and then perform sandblasting and derusting treatment;

[0027] S3. Under nitrogen protection, raise the temperature of the billet obtained in S2 to 750°C, hold it for 40 minutes, quench to 400°C, hold it for 6 minutes, temper it again to 650°C, hold it for 3 minutes, cool it down to 300°C at a rate of 4°C / min, and air cool...

Embodiment 2

[0030] A method for producing high-weather-resistant bolts, comprising the steps of:

[0031] S1, rolling the cast ingot into a billet with a diameter of 30mm, and then sequentially undergoing pickling, end face chamfering, flat head, head forming, and head chamfering to obtain a billet;

[0032] The chemical composition of the ingot includes: C: 0.32%, Si: 0.02%, Mn: 0.45%, Cr: 0.55%, Nb: 0.014%, Ni: 0.04%, Cu: 0.16%, V: 0.02%, Ti: 0.018%, Zr: 0.001%, Re: 0.002%, P≤0.002%, S≤0.002%, the balance is Fe and other unavoidable impurities;

[0033] S2, using a potassium hydroxide solution with a pH value of 7.2 to degrease the billet obtained in S1, and then perform sandblasting and derusting treatment;

[0034] S3. Under the protection of nitrogen, raise the temperature of the billet obtained in S2 to 780°C, hold it for 20 minutes, quench it to 420°C, hold it for 2 minutes, temper it again to 680°C, hold it for 1 minute, cool it down to 250°C at a rate of 6°C / min, and air-cool it...

Embodiment 3

[0037] A method for producing high-weather-resistant bolts, comprising the steps of:

[0038] S1, rolling the cast ingot into a billet with a diameter of 26mm, and then sequentially undergoing pickling, end face chamfering, flat head, head forming, and head chamfering to obtain a billet;

[0039] The chemical composition of the ingot includes by mass percentage: C: 0.29%, Si: 0.05%, Mn: 0.34%, Cr: 0.60%, Nb: 0.011%, Ni: 0.07%, Cu: 0.12%, V: 0.035%, Ti: 0.013%, Zr: 0.004%, Re: 0.0013%, P≤0.002%, S≤0.002%, the balance is Fe and other unavoidable impurities;

[0040] S2, using a sodium carbonate solution with a pH value of 7.8 to degrease the billet obtained in S1, and then perform sandblasting and derusting treatment;

[0041] S3. Under the protection of nitrogen, raise the temperature of the billet obtained in S2 to 760°C, hold it for 35 minutes, quench it to 405°C, hold it for 5 minutes, temper it again to 660°C, hold it for 2.5 minutes, and cool it down to 280°C at a speed o...

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Abstract

The invention discloses a production method of a high-weather-resistance bolt. The production method comprises the following steps that a cast ingot is rolled into a strip blank, and then acid pickling, end face chamfering, head flattening, head forming and head chamfering are sequentially carried out to obtain a blank; the obtained blank is degreased by adopting alkali liquor, and then sand blasting rust removal treatment is carried out; under the protection of nitrogen, the obtained blank is heated to 750-780 DEG C, subjected to heat preservation for 20-40 minutes, quenched to 400-420 DEG C,subjected to heat preservation for 2-6 minutes, tempered again to 650-680 DEG C, subjected to heat preservation for 1-3 minutes, cooled to 250-300 DEG C and subjected to air cooling to the room temperature; and the surface of the obtained workpiece is phosphated, and cleaning is carried out to obtain the high-weather-resistance bolt. The strength of the high-weather-resistance bolt can reach 1200MPa or above, the industrial atmospheric corrosion resistance is excellent, the atmospheric corrosion resistance index I is larger than 7.2, the bolt manufacturing process is simple and easy to implement, and the high-weather-resistance bolt is suitable for industrial application.

Description

technical field [0001] The invention relates to the technical field of bolt production, in particular to a production method for highly weather-resistant bolts. Background technique [0002] Bolt is the basic part that all fields of national economy will use. Bolts are prone to oxidation reaction with oxygen in the air and rust during use, so anti-rust treatment is required. The usual anti-rust treatment mainly relies on techniques such as coating, electroplating, and hot-dip galvanizing to form a protective layer on the bolt surface. However, the corrosion resistance, weather resistance and wear resistance of bolts are often a pair of contradictory considerations. Generally, the weather resistance is high, but the wear resistance is poor. [0003] At present, the high-strength bolts used in steel structure bridges, towers and other infrastructure facilities are mainly 12.9 grades. Due to the long-term corrosion-prone environment, ordinary 12.9 grade high-strength bolts ca...

Claims

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Application Information

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IPC IPC(8): C21D1/18C21D1/74C22C38/02C22C38/04C22C38/48C22C38/42C22C38/46C22C38/50
CPCC21D1/18C21D1/74C22C38/005C22C38/02C22C38/04C22C38/42C22C38/46C22C38/48C22C38/50
Inventor 汪豪豪曾晖陈元张楠楠杨照军
Owner ANHUI CHANGJIANG FASTENERS
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