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Steel for high-strength fasteners containing nickel and copper and heat treatment method thereof

A heat treatment method and fastener technology, applied in the field of microalloyed steel, can solve problems such as mechanical properties that cannot meet requirements, and achieve the effects of facilitating promotion, saving time and cost, and improving strength and toughness

Active Publication Date: 2017-05-10
ANHUI UNIVERSITY OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] In order to overcome the deficiency that the mechanical properties of the steel for fasteners in the prior art cannot meet the requirements, the present invention provides a nickel-copper-containing high-strength fastener steel and a heat treatment method thereof; the high-strength fastener steel provided by the invention With stable impact performance and high strength, it can be used to make 10.9 grade delayed fracture resistant high-strength fasteners

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  • Steel for high-strength fasteners containing nickel and copper and heat treatment method thereof
  • Steel for high-strength fasteners containing nickel and copper and heat treatment method thereof
  • Steel for high-strength fasteners containing nickel and copper and heat treatment method thereof

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Embodiment 1

[0028] A kind of nickel-copper-containing high-strength fastener steel of the present embodiment, the selected chemical components and the mass percentage ratio of each component are shown in Table 1:

[0029] Table 1 Mass percentage distribution table of chemical components of steel for high-strength fasteners in Examples 1 to 4

[0030]

[0031] In this embodiment, the steel material is processed into a round bar of Φ25mm by ordinary machining, and then heat-treated. The heat treatment process is as follows: quench the round bar with quenching oil at a temperature of 920 °C for 35 minutes; temper when the oil is cooled to 200 °C, the tempering temperature is 550 °C, and the holding time is 3.5 hours. to room temperature.

[0032] The tensile strength Rm, yield strength Rel, elongation ψ and toughness (impact energy Akv) of the high-strength fastener steel prepared in this embodiment are detected, and the detection results are shown in Table 2:

[0033] Table 2 The perform...

Embodiment 2

[0037] For a high-strength fastener steel containing nickel and copper in this embodiment, see Table 1 for the selected chemical components and the mass percentage distribution of each component.

[0038] In this embodiment, the heat treatment process of steel for high-strength fasteners is as follows: the round bar is quenched with quenching oil at a temperature of 925 ° C, and the treatment time is 37 minutes; when the oil is cooled to 150 ° C, it is tempered, and the tempering temperature temperature is 560°C, the holding time is 3h, and the furnace is air-cooled to room temperature.

[0039] The tensile strength Rm, yield strength Rel, elongation ψ and toughness (impact energy Akv) of the steel for high-strength fasteners prepared in this example were tested, and the test results are shown in Table 2.

[0040] The microstructure of the steel for high-strength fasteners prepared in this embodiment was observed, see figure 2 . From figure 2 It can be seen from the micro...

Embodiment 3

[0042] For a high-strength fastener steel containing nickel and copper in this embodiment, see Table 1 for the selected chemical components and the mass percentage distribution of each component.

[0043] In this embodiment, the heat treatment process of high-strength fastener steel is as follows: the round bar is quenched with quenching oil at a temperature of 930 ° C, and the treatment time is 40 minutes; when the oil is cooled to room temperature, it is tempered, and the tempering temperature is 570°C, holding time 3h, take out the oven and air cool to room temperature.

[0044] The tensile strength Rm, yield strength Rel, elongation ψ and toughness (impact energy Akv) of the steel for high-strength fasteners prepared in this example were tested, and the test results are shown in Table 2.

[0045] The microstructure of the steel for high-strength fasteners prepared in this embodiment was observed, see image 3 . From image 3 It can be seen from the microstructure of the...

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Abstract

The invention discloses high-strength fastener steel containing nickel and copper and a thermal treatment method for high-strength fastener steel. The high-strength fastener steel comprises the following components in percentage by mass: 0.38-0.45% of C, 0.17-0.30% of Si, 0.60-0.80% of Mn, less than or equal to 0.010% of P, less than or equal to 0.010% of S, 0.90-1.20% of Cr, 0.15-0.22% of Mo, 0.05-0.15% of Ni, 0.10-0.20% of Cu, and the balance of Fe and inevitable impurities. According to the high-strength fastener steel, a tissue obtained by oil quenching and high-temperature tempering is a tempered sorbite tissue with performances as follows: tensile strength Rm equal to 1100-1135MPa, yield strength Rel equal to 980-1015MPa, elongation A equal to 14.5-17.2%, V notch impact energy Akv equal to 70-90J at 25 DEG C, and V notch impact energy Akv equal to 55-85J at (-)20 DEG C. The high-strength fastener steel has stable impact performance and relatively high strength, and can be used for manufacturing a high-strength fastener with delayed fracture resistance of level 10.9.

Description

technical field [0001] The invention relates to micro-alloy steel in the iron and steel industry, in particular to the design of steel types for high-strength and high-toughness fastener steels. Background technique [0002] Fasteners are a type of mechanical parts used for fastening connections and are widely used. They are widely used in various machinery, equipment, vehicles, railways, etc., and are one of the key components in many core equipment. In recent years, with the rapid development of my country's rail transit industry, the demand for high-performance fasteners is increasing. However, due to the mismatch of strength and toughness of domestic high-strength fasteners, a large number of high-strength fasteners for rail transit mobile equipment still need to be imported. [0003] The domestic 42CrMo steel traditionally used to manufacture fasteners cannot meet the requirements of its mechanical properties due to its unreasonable chemical composition. In order to i...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/42C21D6/00
Inventor 范鼎东孙维沈乾坤周庆子陆强刘威
Owner ANHUI UNIVERSITY OF TECHNOLOGY