CN119592878B - Wire rod for fastener, ultra-high strength fastener with low yield ratio and manufacturing method of ultra-high strength fastener - Google Patents
Wire rod for fastener, ultra-high strength fastener with low yield ratio and manufacturing method of ultra-high strength fastenerInfo
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- CN119592878B CN119592878B CN202311161038.2A CN202311161038A CN119592878B CN 119592878 B CN119592878 B CN 119592878B CN 202311161038 A CN202311161038 A CN 202311161038A CN 119592878 B CN119592878 B CN 119592878B
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
- C21D1/32—Soft annealing, e.g. spheroidising
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/52—Ferrous alloys, e.g. steel alloys containing chromium with nickel with cobalt
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/002—Bainite
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
Abstract
The invention discloses a wire rod for a fastener, which contains Fe, unavoidable impurities and the following chemical elements in percentage by mass: c:0.30 to 0.50wt.%, mn:0.30 to 1.50wt.%, ni:0.40 to 0.80wt.%, cr:0.80 to 1.40wt.%, mo:0.80 to 1.40wt.%, ti:0.05 to 0.20wt.%, cu:0.50 to 1.30 weight percent of Co:0.50 to 1.50 weight percent of Ca: 0.002-0.010 wt%. Correspondingly, the invention also discloses a manufacturing method of the wire rod, a fastener manufactured by the wire rod and a manufacturing method of the fastener. The invention can obtain the ultra-high strength fastener with low yield ratio.
Description
Technical Field
The invention relates to steel and a preparation method thereof, in particular to a fastener wire rod and a preparation method thereof.
Background
The ultra-high strength fastener can reduce the weight and increase the installation space by reducing the size of the ultra-high strength fastener under the same clamping force, so that the function and the volume of the connected parts can be optimized, and the equipment achieves the aims of overall weight reduction and performance optimization. Therefore, the steel for the ultra-high strength fasteners is an important research direction in the field of the current steel grades.
For example, chinese patent document publication No. CN1900343a, publication No. 1 month and 24 days 2007, entitled "method for manufacturing steel having a tensile strength of 1600MPa or more and a molded article thereof, which are excellent in delayed fracture resistance", discloses a method for manufacturing steel having a tensile strength of 1600MPa or more and a molded article thereof, which are excellent in delayed fracture resistance, and in which carbide precipitation is caused to significantly secondarily harden by adding 3.0 to 10.0% Mo, thereby improving the strength of the steel. The tensile strength of the steel grade prepared by the method reaches 1600MPa, but the Mo content in the steel grade is higher.
For example, chinese patent document CN1900344a, publication No. 1/24/2007, entitled "high strength bolt excellent in delayed fracture resistance and method for producing the same", discloses a high strength bolt excellent in delayed fracture resistance and method for producing the same, in which a steel material is formed into a bolt head portion and a shaft portion, and then heated to 900 to 1100 ℃ and quenched, and then tempered at 580 ℃ or higher, with a maximum strength of 1864MPa, but the patent does not require a yield ratio of the material.
Also for example, chinese patent literature with publication No. CN112981277a, publication No. 2021, 6/18, entitled "method for preparing ultra-high strength medium carbon nano bainitic steel" discloses a method for preparing ultra-high strength medium carbon nano bainitic steel, which comprises subjecting medium carbon nano bainitic steel after complete austenitization and low temperature bainitic transformation to room temperature rolling deformation, wherein single pass reduction should be controlled to be 4% or more, accumulated reduction is at least 15%, and then performing medium temperature tempering treatment. The patent does not address the requirement of the yield ratio of the material.
It can be seen that the tensile strength of the material is mainly focused in the prior art, but the emphasis on the yield ratio is insufficient, so that the invented material is difficult to meet the tightening process requirement of the high-end bolt.
Disclosure of Invention
The invention aims to provide a wire rod for a fastener, which can obtain a wire rod for a hot rolled fastener with quite excellent mechanical properties through reasonable chemical composition design and matching with a manufacturing process, and can obtain an ultrahigh-strength fastener with low yield ratio after an isothermal heat treatment process is adopted.
In order to achieve the above object, the present invention provides a wire rod for a fastener, which contains Fe and unavoidable impurities, and further contains the following chemical elements in mass percent:
C：0.30～0.50wt.％、Mn：0.30～1.50wt.％、Ni：0.40～0.80wt.％、Cr：0.80～1.40wt.％、Mo：0.80～1.40wt.％、Ti：0.05～0.20wt.％、Cu：0.50～1.30wt％、Co：0.50～1.50wt％、Ca：0.002～0.010wt％.
correspondingly, the invention also provides a wire rod for the fastener, which comprises the following chemical elements in percentage by mass:
C：0.30～0.50wt.％、Mn：0.30～1.50wt.％、Ni：0.40～0.80wt.％、Cr：0.80～1.40wt.％、Mo：0.80～1.40wt.％、Ti：0.05～0.20wt.％、Cu：0.50～1.30wt％、Co：0.50～1.50wt％、Ca：0.002～0.010wt％; The balance being Fe and unavoidable impurities.
In the fastener wire rod of the invention, the design principle of each chemical element is as follows:
In the wire rod for the fastener, C is an element with effective strength, and the addition of a proper amount of C element in steel is beneficial to the strength of the steel. However, it should be noted that the content of C element in the steel is not too high, and when the content of C element in the steel is too high, cold heading property, toughness and delayed fracture resistance of the steel are adversely affected. Based on the above, from the comprehensive consideration of the strength, cold heading property, toughness, delayed fracture resistance and the like of the material, the mass percentage of the C element can be controlled to be 0.30-0.50wt%.
Mn in the wire rod for a fastener according to the present invention, mn is an important element for stabilizing an austenite phase on the one hand, and S in steel is fixed by forming MnS form on the other hand, thereby having an effect of preventing hot shortness. If the Mn content is too high, segregation of grain boundaries is likely to occur, and the grain boundary strength is lowered. Based on the above, in the invention, the mass percentage of Mn element is controlled to be 0.30-1.50wt%.
In the wire rod for the fastener, ni has the effects of stabilizing austenite, increasing hardenability, improving low-temperature toughness and the like, and in addition, the Ni element can improve the structure of an iron oxide layer, improve the compactness, improve the corrosion resistance of steel and inhibit the adsorption of hydrogen, so that the wire rod has positive effects on the delayed fracture resistance of the steel. Therefore, in the invention, the mass percentage of Ni can be controlled to be 0.40-0.80 wt.% in consideration of cost factors.
Cr in the wire rod for a fastener according to the present invention has an effect of improving hardenability and corrosion resistance of steel, and is effective in strength and delayed fracture resistance of steel. However, it should be noted that the Cr element content in the steel is not too high, and when the Cr element content in the steel is too high, the cold workability of the steel is lowered and the production cost is increased. Based on the above, in the invention, the mass percentage of Cr element is controlled to be 0.80-1.40 wt%.
Mo in the wire rod for the fastener, mo is mainly precipitated in a heat treatment stage to form Mo-containing carbide, so that remarkable secondary strengthening is generated. However, it should be noted that it is not preferable to add excessive Mo to the steel, which leads to an increase in material cost. Therefore, the mass percentage of Mo element can be controlled to be 0.80-1.40 wt.% in the invention by comprehensively considering cost factors.
Ti is precipitated from C, N in steel in the wire rod for fastener of the invention, and can refine austenite grains in the heating stage of steel, thereby improving the strength of steel plate. However, too much Ti forms coarse inclusions, which is detrimental to the properties of the steel. Therefore, in the invention, the mass percentage of Ti element is controlled to be 0.05-0.20 wt%.
Cu in the wire rod for the fastener, disclosed by the invention, the Cu can improve corrosion resistance and inhibit hydrogen invasion, so that the delayed fracture resistance of steel is further improved, the effect cannot be achieved when the content of Cu element is lower than 0.5%, but the high-temperature plasticity of the steel is reduced when the content of Cu element is too high, cracks are easily generated in the hot working process, and therefore, the content of Cu is controlled to be 0.50-1.30wt%.
Co in the wire rod for the fastener, the Co element serving as a core element can improve the free energy difference of phase transformation, promote the phase transformation of bainite and enable a phase transformation kinetic curve to move leftwards, so that the purpose of shortening the phase transformation time of the bainite is achieved. Based on the above, the Co content is controlled to be 0.50-1.50wt%.
Ca in the wire rod for the fastener, ca element improves the fluidity of molten steel, changes the components, the quantity and the form of nonmetallic inclusion, improves the purity of steel, and also plays a role in desulfurization. Based on the above, the Ca content is controlled to be 0.002-0.010wt%.
Further, in a preferred embodiment of the present invention, the fastener wire rod further contains 0< Si≤0.20 wt.%.
In the preferred technical scheme of the invention, si is used for inhibiting cementite precipitation in bainitic steel and can be dissolved in ferrite, thereby playing a role of solid solution strengthening and further improving the strength and hardness of the steel plate, but the content of Si is too high, so that the plasticity and toughness of the steel are obviously reduced. Based on this, in a preferred embodiment of the present invention, si element is added and the upper limit thereof is controlled to 0.20wt.%.
Further, among the unavoidable impurities of the wire rod for fasteners of the present invention, P is 0.015wt.% or less and S is 0.015wt.% or less.
The impurity elements in the wire rod for the fastener are mainly P element and S element. In order to obtain a steel product with better performance and better quality, the content of impurity elements in the steel should be reduced as much as possible under the condition of allowable technical conditions. Wherein, the impurity elements P and S are easy to generate segregation at the grain boundary, the toughness of the steel is reduced, and the cold workability of the steel is greatly influenced, so that in some embodiments, P is less than or equal to 0.015wt.% and S is less than or equal to 0.015wt.%.
Further, the microstructure of the wire rod for the fastener is martensite+bainite+pearlite.
Further, the volume phase proportion of the martensite is 5-30%.
The invention further aims to provide the ultrahigh-strength fastener with low yield ratio, which is prepared by adopting the wire rod for the fastener and through an isothermal heat treatment process, has low yield ratio and ultrahigh strength, can be effectively applied to bolts and related products in the fields of vehicles, ships, constructional engineering, energy sources, bridge traffic and the like, and has very good popularization prospect and application value.
Based on the above object, the present invention provides an ultra-high strength fastener with low yield ratio, which is prepared by using the wire rod for the fastener through isothermal heat treatment.
Further, the microstructure of the ultra-high strength fastener with low yield ratio is martensite and bainite.
Further, the tensile strength of the ultra-high strength fastener with low yield ratio is more than or equal to 1800MPa, and the yield ratio is 0.8-0.9.
It is still another object of the present invention to provide a method of manufacturing a wire rod for fasteners.
Based on the above object, the present invention also provides a method for manufacturing a wire rod for a fastener as described above, comprising the steps of:
smelting and casting;
rolling into a wire rod;
and slowly cooling at a cooling speed of less than or equal to 5 ℃ per second by adopting a Steyr air cooling line.
In the method for manufacturing a wire rod for a fastener according to the present invention, after the wire rod is rolled, the wire rod is gradually cooled by a stelmor wire because the wire rod has high hardenability, and if the cooling rate is high, a large amount of abnormal martensitic structure is likely to occur.
Further, in the method for manufacturing the wire rod for the fastener, in the step of rolling the wire rod, the initial rolling temperature is controlled to 1090-1180 ℃, the inlet temperature of the finishing mill is controlled to 980-1030 ℃, the inlet temperature of the reducing sizing mill is controlled to 900-950 ℃, and the wire laying temperature is controlled to 840-880 ℃.
It is still another object of the present invention to provide a method for manufacturing an ultra-high strength fastener with a low yield ratio, which is easy to operate, and can obtain an ultra-high strength fastener with a low yield ratio, so as to be effectively applied to bolts and related products in the fields of vehicles, ships, construction engineering, energy sources, bridge traffic, etc.
Based on the above object, the present invention also provides a method for manufacturing an ultra-high strength fastener with low yield ratio as described above, comprising the steps of:
smelting and casting;
rolling into a wire rod;
Slowly cooling at a cooling speed of less than or equal to 5 ℃ per second by adopting a Steyr air cooling line;
Isothermal spheroidizing annealing;
machining the appearance of the part;
and (3) isothermal heat treatment, namely heating to the austenitizing temperature of 860-940 ℃, preserving heat for 30-90 min, and then cooling to 250-400 ℃ at the speed of 15-30 ℃ per second, and preserving heat for 60-180 min.
In the manufacturing method of the fastener, on the basis of the manufactured wire rod, the invention optimizes the tissue performance of the wire rod by adopting isothermal spheroidizing annealing treatment so as to improve the plasticity of the material and prevent the quality problems of cracking, surface roughness and the like in the processing and forming process of the part. After the appearance of the part is processed, special designed isothermal heat treatment is adopted to obtain the fastener with tensile strength more than or equal to 1800MPa and yield ratio of 0.8-0.9.
Further, in the manufacturing method of the fastener, in the step of rolling into the wire rod, the initial rolling temperature is controlled to 1090-1180 ℃, the inlet temperature of the finishing mill is controlled to 980-1030 ℃, the inlet temperature of the reducing sizing mill is controlled to 900-950 ℃, and the spinning temperature is controlled to 840-880 ℃.
In the isothermal heat treatment step, the isothermal medium may employ a molten salt solution. Molten salt solution can also be used as the quenching cooling medium.
The wire rod for the fastener and the fastener have the following advantages and beneficial effects:
According to the invention, the ultra-high strength fastener with low yield ratio can be obtained by reasonably designing chemical components, particularly accurately controlling the content of C, si, mn, ni, cr, mo, cu, co, ca and matching with an optimized isothermal heat treatment process.
In some embodiments, the tensile strength of the fastener is more than or equal to 1800MPa, and the yield ratio is 0.8-0.9.
The fastener disclosed by the invention has lower alloy cost and excellent strong plasticity, can realize a yield ratio of 0.8-0.9 on the premise that the tensile strength is more than or equal to 1800MPa, has a wider plastic deformation area, is favorable for controlling the tightening force during bolt assembly, and can be effectively applied to bolts and related products in the fields of vehicles and ships, constructional engineering, energy sources, bridge traffic and the like, and has very good popularization prospect and application value.
Detailed Description
The wire rod for a fastener, the fastener and the method of manufacturing the same according to the present invention will be further explained and illustrated with reference to specific examples, but the explanation and illustration do not constitute undue limitations on the technical solution of the present invention.
Examples 1 to 6
The fastener coils of examples 1-6 were each made using the following steps:
(1) Smelting, secondary refining and casting to obtain casting blanks, wherein the mass percentage ratios of each chemical element in each embodiment of the invention are shown in table 1.
(2) Rolling into wire rods, wherein the initial rolling temperature is controlled to be 1090-1180 ℃, the inlet temperature of a finishing mill is controlled to be 980-1030 ℃, the inlet temperature of a reducing sizing mill is controlled to be 900-950 ℃, the spinning temperature is controlled to be 840-880 ℃, and the specification of the wire rods is phi 5.5-20 mm.
(3) And slowly cooling the rolled wire rod through a stelmor air cooling line at the cooling speed of less than or equal to 5 ℃ per second so as to cool the wire rod to room temperature.
In some embodiments, all fans may be turned off and covered with a heat shield to effect slow cooling as the wire rod passes through the stelmor air cooling line.
The fasteners of examples 1-6 were made based on the wire rods obtained in each example using the following steps:
(4) Isothermal spheroidizing annealing.
(5) And carrying out appearance machining on the parts of the annealed wire rods through the working procedures of drawing, cold heading, turning and milling.
(6) And the isothermal heat treatment is carried out by heating to the austenitizing temperature of 860-940 ℃, preserving heat for 30-90 min, cooling to 250-400 ℃ at the speed of 15-30 ℃ per second, and preserving heat for 60-180 min. In the cooling and isothermal operation, molten salt solution is adopted as isothermal and cooling media so as to ensure rapid cooling and accurate temperature control of parts.
Table 1 shows the mass percentages of the chemical elements of examples 1 to 6.
Table 1 (wt.%), the balance Fe and unavoidable impurities other than P, S
Table 2 lists the specific process parameters for the manufacture of wire rods for examples 1-6.
Table 2.
Table 3 sets forth specific process parameters for isothermal heat treatments for the manufacture of fasteners of examples 1-6.
Table 3.
The wire rods of examples 1-6 and the final fasteners prepared were individually sampled for observation and analysis of their microstructure, and the results of the relevant observations and analyses are set forth in table 4 below.
Table 4 sets forth the microstructure characteristics of the coils and fasteners of examples 1-6.
Table 4.
In addition, in order to verify the mechanical properties of the fasteners of each example, the inventors re-sampled the fasteners of examples 1 to 6 obtained through the above-described process steps, and conducted mechanical property tests on the fasteners of each example, and the obtained mechanical property test results are shown in table 5. The specific detection method is as follows:
the tensile test is carried out according to the national standard GB/T228.1-2010 section 1 of tensile test of metallic materials: room temperature test method, and the test environment is 10-35 ℃ at room temperature. .
Table 5 sets forth the results of the performance testing of the fasteners of examples 1-6.
Table 5.
| Numbering device | Yield strength (MPa) | Tensile strength (MPa) | Yield ratio |
| Example 1 | 1529 | 1820 | 0.84 |
| Example 2 | 1606 | 1846 | 0.87 |
| Example 3 | 1588 | 1868 | 0.85 |
| Example 4 | 1554 | 1872 | 0.83 |
| Example 5 | 1631 | 1896 | 0.86 |
| Example 6 | 1580 | 1859 | 0.85 |
As can be seen from Table 5, the fasteners of examples 1 to 6 of the present invention all had tensile strengths of 1800MPa or more, yield strengths of 1520MPa or more, and yield ratios of 0.8 to 0.9. Therefore, the bolt is favorable for controlling the tightening force during bolt assembly, and can be applied to bolts and related products in the fields of vehicles and ships, constructional engineering, energy, bridge traffic and the like.
In addition, the combination of the features described in the present application is not limited to the combination described in the claims or the combination described in the embodiments, and all the features described in the present application may be freely combined or combined in any manner unless contradiction occurs between them.
It should also be noted that the above-recited embodiments are merely specific examples of the present invention. It is apparent that the present invention is not limited to the above embodiments, and similar changes or modifications will be apparent to those skilled in the art from the present disclosure, and it is intended to be within the scope of the present invention.
Claims (10)
1. The wire rod for the fastener is characterized by comprising the following chemical elements in percentage by mass:
C：0.30~0.50wt.%、Mn：0.30~1.50wt.%、Ni：0.40~0.80wt.%、Cr：0.80~1.40wt.%、Mo：0.80~1.40wt.%、Ti：0.05~0.20wt.%、Cu：0.50~1.30wt.%、Co：0.50~1.50wt.%、Ca：0.002~0.010wt.%; The balance of Fe and unavoidable impurities;
the microstructure of the wire rod for the fastener is martensite, bainite and pearlite, wherein the volume phase proportion of the martensite is 5-30%.
2. The wire rod for fasteners of claim 1 further comprising 0< si +.0.20 wt%.
3. The wire rod for fasteners according to claim 1 characterized in that among unavoidable impurities P≤0.015 wt.%, S≤0.015 wt.%.
4. An ultra-high strength fastener with low yield ratio, which is prepared by performing isothermal heat treatment on the wire rod for the fastener according to any one of claims 1 to 3.
5. The ultra-high strength fastener of claim 4, wherein the microstructure is martensite+bainite.
6. The ultra-high strength fastener with low yield ratio according to claim 4, wherein the tensile strength is not less than 1800MPa and the yield ratio is 0.8-0.9.
7. A method of manufacturing a wire rod for fasteners as defined in any one of claims 1-3 comprising the steps of:
smelting and casting;
rolling into a wire rod;
and slowly cooling at a cooling speed of less than or equal to 5 ℃ per second by adopting a Steyr air cooling line.
8. The method according to claim 7, wherein in the step of rolling into the wire rod, the initial rolling temperature is controlled to 1090 to 1180 ℃, the finishing mill inlet temperature is controlled to 980 to 1030 ℃, the reducing mill inlet temperature is controlled to 900 to 950 ℃, and the spinning temperature is controlled to 840 to 880 ℃.
9. A method of making a low yield ratio ultra high strength fastener according to any of claims 4-6, comprising the steps of:
smelting and casting;
rolling into a wire rod;
Slowly cooling at a cooling speed of less than or equal to 5 ℃ per second by adopting a Steyr air cooling line;
Isothermal spheroidizing annealing;
machining the appearance of the part;
and (3) isothermal heat treatment, namely heating to the austenitizing temperature of 860-940 ℃, preserving heat for 30-90 min, and then cooling to 250-400 ℃ at the speed of 15-30 ℃ per second, and preserving heat for 60-180 min.
10. The method according to claim 9, wherein in the step of rolling into the wire rod, an initial rolling temperature is controlled to 1090 to 1180 ℃, a finishing mill inlet temperature is controlled to 980 to 1030 ℃, a reducing mill inlet temperature is controlled to 900 to 950 ℃, and a spinning temperature is controlled to 840 to 880 ℃.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US5374322A (en) * | 1992-07-09 | 1994-12-20 | Sumitomo Metal Industries, Ltd. | Method of manufacturing high strength steel member with a low yield ratio |
| CN107636184A (en) * | 2015-06-11 | 2018-01-26 | 新日铁住金株式会社 | Alloyed hot-dip galvanized steel sheet and manufacturing method thereof |
| CN115572917A (en) * | 2021-06-21 | 2023-01-06 | 宝山钢铁股份有限公司 | A kind of economical fastener steel and its manufacturing method |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5374322A (en) * | 1992-07-09 | 1994-12-20 | Sumitomo Metal Industries, Ltd. | Method of manufacturing high strength steel member with a low yield ratio |
| CN107636184A (en) * | 2015-06-11 | 2018-01-26 | 新日铁住金株式会社 | Alloyed hot-dip galvanized steel sheet and manufacturing method thereof |
| CN115572917A (en) * | 2021-06-21 | 2023-01-06 | 宝山钢铁股份有限公司 | A kind of economical fastener steel and its manufacturing method |
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