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CN-122013064-A - High-strength anti-theft bolt and preparation method thereof

CN122013064ACN 122013064 ACN122013064 ACN 122013064ACN-122013064-A

Abstract

The invention relates to the technical field of bolts, and provides a high-strength anti-theft bolt and a preparation method thereof, wherein the bolt comprises C, si, mn, cr, W, mo, V, re, nb, al, N, ca, B, P, S and the balance of Fe and other unavoidable impurities. Through the technical scheme, the ultra-high strength, the excellent toughness and the delayed fracture resistance of the bolt are realized, the corrosion resistance of the bolt is improved, and the service life of the bolt is prolonged.

Inventors

  • DAI LEI

Assignees

  • 河北东润紧固件有限公司

Dates

Publication Date
20260512
Application Date
20260225

Claims (10)

  1. 1. A high-strength anti-theft bolt is characterized by comprising the following components in percentage by mass ：C 0.30%~0.38%、Si 0.15%~0.30%、Mn 0.40%~0.70%、Cr 0.80%~1.20%、W 0.80%~1.20%、Mo 0.40%~0.60%、V 0.25%~0.35%、Re 0.08%~0.15%、Nb 0.03%~0.06%、Al 0.020%~0.040%、N 0.010%~0.020%、Ca 0.001%~0.005%、B 0.001%~0.003%、P≤0.010%、S≤0.010%, and the balance of Fe and other unavoidable impurities.
  2. 2. The high-strength anti-theft bolt according to claim 1, wherein the bolt comprises ：C 0.30%~0.38%、Si 0.15%~0.30%、Mn 0.40%~0.70%、Cr 0.80%~1.20%、W 0.80%~1.20%、Mo 0.40%~0.60%、V 0.25%~0.35%、Re 0.08%~0.15%、Nb 0.03%~0.06%、Al 0.020%~0.040%、N 0.010%~0.020%、Ca 0.001%~0.005%、B 0.001%~0.003%、P≤0.010%、S≤0.010%, parts by mass of Fe and other unavoidable impurities in balance, and the weight ratio of (W+Mo)/V is 3.5-5.5.
  3. 3. The high-strength anti-theft bolt according to claim 1, wherein the bolt comprises the following components in percentage by mass ：C 0.30%~0.38%、Si 0.15%~0.30%、Mn 0.40%~0.70%、Cr 0.80%~1.20%、W 0.80%~1.20%、Mo 0.40%~0.60%、V 0.25%~0.35%、Re 0.08%~0.15%、Nb 0.03%~0.06%、Al 0.020%~0.040%、N 0.010%~0.020%、Ca 0.001%~0.005%、B 0.001%~0.003%、P≤0.010%、S≤0.010%,, and the balance of Fe and other unavoidable impurities, and the weight ratio Re/(P+S) is not less than 8.
  4. 4. The high-strength anti-theft bolt according to claim 1, wherein the bolt comprises ：C 0.30%~0.38%、Si 0.15%~0.30%、Mn 0.40%~0.70%、Cr 0.80%~1.20%、W 0.80%~1.20%、Mo 0.40%~0.60%、V 0.25%~0.35%、Re 0.08%~0.15%、Nb 0.03%~0.06%、Al 0.02%~0.04%、N 0.01%~0.02%、Ca 0.001%~0.005%、B 0.001%~0.003%、P≤0.01%、S≤0.01%, parts by mass of Fe and other unavoidable impurities in balance, and the weight ratio of Ca/S is 0.5-2.0.
  5. 5. The high-strength anti-theft bolt according to claim 1, wherein an Al-Zn-Mg alloy layer and a diamond-like carbon film are sequentially deposited on the surface of the bolt.
  6. 6. The high-strength anti-theft bolt according to claim 5, wherein the Al-Zn-Mg alloy layer has a thickness of 2-3 μm and the diamond-like carbon film has a thickness of 1-2 μm.
  7. 7. The high-strength anti-theft bolt according to claim 5, wherein the Al-Zn-Mg alloy layer comprises 50% -70% by mass of Al, 25% -40% by mass of Zn and 5% -15% by mass of Mg.
  8. 8. A method of manufacturing a high strength anti-theft bolt according to any one of claims 1 to 7, comprising the steps of: t1, smelting and forming, namely smelting by adopting a vacuum induction smelting and electroslag remelting duplex process, controlling the oxygen content to be less than or equal to 15ppm; T2, carrying out gradient austenitizing treatment, namely heating the bolt blank to 900-920 ℃ and preserving heat for 30-60 min under a protective atmosphere, and then heating to 1050-1100 ℃ and preserving heat for 10-20 min; T3, quenching the workpiece treated in the step T2 to 200-250 ℃ and staying for 5-15 s, then continuously cooling to room temperature, and then transferring to a salt bath at 300-350 ℃ for isothermal treatment for 2-5 min; t4, carrying out multi-section tempering treatment, namely sequentially carrying out three tempering, wherein the first tempering temperature is 500-520 ℃, the heat preservation is carried out for 2 hours, the second tempering temperature is 540-560 ℃, the heat preservation is carried out for 2 hours, and the third tempering temperature is 300-350 ℃, and the heat preservation is carried out for 3 hours; and T5, depositing a surface coating, namely sequentially depositing an Al-Zn-Mg alloy layer and a diamond-like carbon film on the surface of the bolt by adopting a high-power pulse magnetron sputtering technology.
  9. 9. The method for manufacturing the high-strength anti-theft bolt according to claim 8, wherein the electroslag remelting current in the step T1 is 4000-6000A, and the melting speed is 3-5 kg/min.
  10. 10. The method for manufacturing the high-strength anti-theft bolt according to claim 8, wherein in the step T3, the cooling rate from 1050-1100 ℃ to 200-250 ℃ is more than or equal to 50 ℃ per second, and the continuous cooling to room temperature adopts high-speed argon spray quenching.

Description

High-strength anti-theft bolt and preparation method thereof Technical Field The invention relates to the technical field of bolts, in particular to a high-strength anti-theft bolt and a preparation method thereof. Background The bolt is used as a key foundation piece in the field of mechanical connection, is widely applied to key engineering fields such as bridges, buildings, rail transit, aerospace and the like, and the performance of the bolt directly determines the safety and reliability of the integral structure. Along with the continuous improvement of the requirements of modern engineering on the material performance, the traditional bolts have difficulty in meeting the requirements of complex working conditions in the aspects of strength, toughness, corrosion resistance, delayed fracture resistance and the like. Patent CN120210668a proposes a high strength bolt and a method for manufacturing the same. The bolt consists of ：C 0.28%~0.35%、Si 0.3%~0.35%、Mn 0.5%~0.6%、Cr 1.2%~1.5%、W 0.18%~0.22%、Co 0.1%~0.3%、Mo 0.2%~0.3%、Nb 0.03%~0.05%、Ti 0.02%～0.05%、Al 0.015%～0.03%、N 0.008%～0.015%、V 0.18%~0.22%、Ce 0.05%~0.12%、Y 0.03%~0.08%、Re 0.03%~0.06%、B 0.002%~0.005%, parts by mass of Fe and other unavoidable impurities in balance. The invention improves the strength of the bolt and further improves the high-temperature stability and corrosion resistance of the bolt. The high-strength steel is easy to fail due to hydrogen-induced delayed fracture in the long-term service process. In the prior art, although the delayed fracture resistance can be improved to a certain extent by adding certain alloying elements (such as niobium Nb and titanium Ti), the effect is limited. Particularly for high-strength anti-theft bolts, the service environment is often worse, and higher requirements are put on the delayed fracture resistance of materials. Aiming at the problems in the prior art, the invention provides a high-strength anti-theft bolt and a preparation method thereof. Disclosure of Invention The invention provides a high-strength anti-theft bolt and a preparation method thereof, which realize the ultra-high strength, excellent toughness and delayed fracture resistance of the bolt, improve the corrosion resistance of the bolt and prolong the service life of the bolt. The technical scheme of the invention is as follows: In a first aspect, the invention provides a high-strength anti-theft bolt, which comprises the following components in percentage by mass ：C 0.30%~0.38%、Si 0.15%~0.30%、Mn 0.40%~0.70%、Cr 0.80%~1.20%、W 0.80%~1.20%、Mo 0.40%~0.60%、V 0.25%~0.35%、Re 0.08%~0.15%、Nb 0.03%~0.06%、Al 0.020%~0.040%、N 0.010%~0.020%、Ca 0.001%~0.005%、B 0.001%~0.003%、P≤0.010%、S≤0.010%, and the balance of Fe and other unavoidable impurities. As a further technical scheme, the bolt consists of the following components in percentage by mass ：C 0.30%~0.38%、Si 0.15%~0.30%、Mn 0.40%~0.70%、Cr 0.80%~1.20%、W 0.80%~1.20%、Mo 0.40%~0.60%、V 0.25%~0.35%、Re 0.08%~0.15%、Nb 0.03%~0.06%、Al 0.020%~0.040%、N 0.010%~0.020%、Ca 0.001%~0.005%、B 0.001%~0.003%、P≤0.010%、S≤0.010%,, wherein the balance of Fe and other unavoidable impurities, and the weight ratio of (W+Mo)/V is 3.5-5.5. As a further technical scheme, the bolt consists of the following components in percentage by mass ：C 0.30%~0.38%、Si 0.15%~0.30%、Mn 0.40%~0.70%、Cr 0.80%~1.20%、W 0.80%~1.20%、Mo 0.40%~0.60%、V 0.25%~0.35%、Re 0.08%~0.15%、Nb 0.03%~0.06%、Al 0.020%~0.040%、N 0.010%~0.020%、Ca 0.001%~0.005%、B 0.001%~0.003%、P≤0.010%、S≤0.010%,, wherein the balance of Fe and other unavoidable impurities, and the weight ratio Re/(P+S) is more than or equal to 8. As a further technical scheme, the bolt consists of the following components in percentage by mass ：C 0.30%~0.38%、Si 0.15%~0.30%、Mn 0.40%~0.70%、Cr 0.80%~1.20%、W 0.80%~1.20%、Mo 0.40%~0.60%、V 0.25%~0.35%、Re 0.08%~0.15%、Nb 0.03%~0.06%、Al 0.020%~0.040%、N 0.010%~0.020%、Ca 0.001%~0.005%、B 0.001%~0.003%、P≤0.010%、S≤0.010%,, wherein the balance of Fe and other unavoidable impurities, and the weight ratio of Ca/S is 0.5-2.0. As a further technical scheme, an Al-Zn-Mg alloy layer and a diamond-like carbon film are sequentially deposited on the surface of the bolt. As a further technical scheme, the thickness of the Al-Zn-Mg alloy layer is 2-3 mu m, and the thickness of the diamond-like carbon film is 1-2 mu m. According to the invention, an Al-Zn-Mg alloy layer and a diamond-like carbon film are sequentially deposited on the surface of a bolt, and a composite coating system with an active protection function is constructed. The Al-Zn-Mg alloy layer is used as a sacrificial anode layer, not only provides a physical barrier for the bolt and blocks the invasion of corrosive medium, but also provides active and long-acting protection for the steel matrix through preferential corrosion when the coating is damaged. The diamond-like carbon film has high hardness, low friction coefficient and good chemical stability, and can further improve the wear resistance and corrosion resistan