1400mpa grade delayed fracture resistant high-strength bolt steel and manufacturing method

A technology for resistant to delayed fracture and high-strength bolts, applied in the field of steel and its manufacturing, can solve problems such as easy delayed fracture, and achieve the effects of reducing production costs, preventing crack propagation, and excellent resistance to delayed fracture.

Active Publication Date: 2021-05-11
NANJING IRON & STEEL CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] Purpose of the invention: In order to solve the problem of delayed fracture of ordinary 10.9 grade and above high-strength bolts used in existing structural steel and automobiles, the present invention provides a 1400MPa grade delayed fracture resistant high-strength bolt steel

Method used

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  • 1400mpa grade delayed fracture resistant high-strength bolt steel and manufacturing method
  • 1400mpa grade delayed fracture resistant high-strength bolt steel and manufacturing method
  • 1400mpa grade delayed fracture resistant high-strength bolt steel and manufacturing method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Example 1: The chemical composition of 42CrMoVNb high-strength bolt steel contains C: 0.43%; Si: 0.14%; Mn: 0.30%; P: 0.003%; S: 0.010%; Cr: 1.10%; Mo: 0.55%; V: 0.33%; Nb: 0.04%; Cu: 0.65%; Al: 0.012%; N: 0.009%;

[0037] The preparation process scheme of table 1 embodiment 1

[0038]

[0039]

[0040] The test results of the technical indicators of the finished products prepared by the above preparation scheme are shown in Table 2.

[0041] Table 2 Example 1 high-strength bolt steel technical index detection results

[0042]

[0043] Such as Figure 1-3 As shown, the cross-sectional metallographic structure and scanning electron microscope of the 42CrMoVNb high-strength bolt steel in the hot-rolled state of Example 1, the structure is mainly bainite and a small amount of martensite, and the Vickers hardness of the test steel in the hot-rolled state is 373-387HV .

Embodiment 2

[0056] Example 2: The chemical composition of high-strength bolt steel contains C: 0.44%, Si: 0.13%, Mn: 0.32%, P: 0.005%, S: 0.009%, Cr: 1.0%, Mo: 0.50 in mass percentage %, Nb: 0.03%, V: 0.31%, Cu: 0.7%, Al: 0.015%, N: 0.018%, and the balance is Fe and impurities. The specific preparation process scheme is shown in Table 6.

[0057] The preparation process scheme of table 6 embodiment 2

[0058]

[0059]

[0060] The test results of the technical indicators of the finished high-strength bolt steel products prepared by the above preparation scheme are shown in Table 7.

[0061] Table 7 Example 2 high-strength bolt steel technical index testing results

[0062]

[0063]

Embodiment 3

[0064] Example 3: The chemical composition of high-strength bolt steel contains C: 0.38%; Si: 0.25%; Mn: 0.60%; P: 0.015%; S: 0.010%; Cr: 0.90%; Mo: 0.60 %; V: 0.35%; Nb: 0.02%; Cu: 0.50%; Ti: 0.01%; N: 0.009%; the balance is Fe and unavoidable impurities. The specific preparation process scheme is shown in Table 8.

[0065] The preparation process scheme of table 8 embodiment 3

[0066]

[0067]

[0068] The test results of the technical indicators of the finished high-strength bolt steel products prepared by the above preparation scheme are shown in Table 9.

[0069] Table 9 Example 3 high-strength bolt steel technical index detection results

[0070]

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Abstract

The invention discloses a 1400MPa grade delayed fracture resistant high-strength bolt steel and a manufacturing method. The high-strength bolt steel has a relatively high Cu element content, and the Cu element can play a role of precipitation strengthening in the steel, and can also promote passivation film formation. When Cu element precipitates and Cu element segregates, it can induce the precipitation of Mo, V, Nb and other elemental carbides, enhance its hydrogen trapping effect, and at the same time prevent crack propagation, so that the tensile strength of the finished bolt is not less than 1400MPa. The reduction of area is not less than 40%, and it has excellent resistance to delayed fracture. The bolt steel does not add rare earth elements, and at the same time strictly controls the addition of other microalloying elements, on the one hand, the production cost is reduced, and on the other hand, the relatively simple process is conducive to mass production.

Description

technical field [0001] The invention relates to a steel material and a manufacturing method thereof, in particular to a 1400MPa grade delayed fracture resistant high-strength bolt steel containing Cu element and a manufacturing method thereof. Background technique [0002] With the development of various aspects of modern automobiles, machinery, construction, and light and heavy industries, the materials used in the manufacture of various fasteners (such as screws, nuts, bolts, etc.) and the tensile strength and delayed fracture performance of the materials themselves have all been raised. higher requirements. For example, high-performance and light-weight automobiles, high-rise building structures, and super-long bridges have put forward high design stress and lightweight requirements for bolts as connecting parts, and strive to meet the constraints of bolt size and space. , Smaller bolts and other solid parts can still provide effective industrial protection. [0003] At...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/28C22C38/26C22C38/24C22C38/22C22C38/20C22C38/06C22C38/04C22C38/02C22C33/04C21D8/06
CPCC21D8/065C21D2211/002C21D2211/008C22C33/04C22C38/001C22C38/002C22C38/02C22C38/04C22C38/06C22C38/20C22C38/22C22C38/24C22C38/26C22C38/28
Inventor 王磊郑宏伟刘文学陈兆勇
Owner NANJING IRON & STEEL CO LTD
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