CN110846567A - High-strength extremely-cold-environment-impact-resistant bolt steel and production method thereof - Google Patents
High-strength extremely-cold-environment-impact-resistant bolt steel and production method thereof Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
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- 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
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- C21D1/18—Hardening; Quenching with or without subsequent tempering
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- 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
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- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
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- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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Abstract
The invention discloses a high-strength extremely cold environment impact-resistant bolt steel and a production method thereof, wherein the bolt steel comprises the following chemical components in percentage by mass: c: 0.40 to 0.43%, Si: 0.20 to 0.25%, Mn: 0.85-0.90%, Cr: 1.05-1.10%, Mo: 0.20 to 0.22%, Ni: 0.20 to 0.25%, Al: 0.025-0.030%, P is less than or equal to 0.018%, S is less than or equal to 0.010%, Nb: 0.03-0.04%, N: 0.0050-0.0070% and the balance of Fe and inevitable impurities; the production method comprises the working procedures of smelting, continuous casting, heating, continuous rolling and heat treatment. The tensile strength Rm of the steel for the bolt is as follows: 1080-1400 MPa, yield strength σ s: 945-1065 MPa, impact energy Akv2 at-120 ℃ is more than or equal to 47J.
Description
Technical Field
The invention belongs to the technical field of metallurgy, and particularly relates to high-strength extremely cold environment impact-resistant bolt steel and a production method thereof.
Background
The high-strength bolt is a vital connecting piece in the installation and integral connection of engineering machinery, and whether the quality of the high-strength bolt can reach the design requirement can directly influence the bearing capacity, the service life and the safety performance of an integral structure. Brittle fracture of high-strength bolts is a very dangerous failure mode, so that providing high-strength bolts with high quality becomes a necessary requirement for ensuring mechanical performance and safety, the requirement is that the grain size is more than or equal to 8.5 grade, and the tensile strength Rm: 1080-1400 MPa, yield strength σ s: 945-1065 MPa, and especially when the bolt bearing a large load is in service in an extremely cold environment, the bolt has high strength and good low-temperature impact toughness at the same time, and the impact energy Akv2 at-120 ℃ is not less than 47J, so that the safe work of the workpiece can be ensured.
At present, the mechanical properties of the traditional bolts with the grades of 35CrMo, 42CrMo and the like cannot reach high strength, and meanwhile, the traditional bolts do not have good low-temperature impact toughness requirements. Therefore, there is a strong demand for development of a steel for bolts that has both high strength and resistance to extreme cold environmental impact.
Disclosure of Invention
The invention aims to provide high-strength extremely cold environment impact-resistant bolt steel and a production method thereof.
In order to solve the technical problems, the invention adopts the technical scheme that: the high-strength and extremely cold environment impact-resistant bolt steel comprises the following chemical components in percentage by mass: c: 0.40 to 0.43%, Si: 0.20 to 0.25%, Mn: 0.85-0.90%, Cr: 1.05-1.10%, Mo: 0.20 to 0.22%, Ni: 0.20 to 0.25%, Al: 0.025-0.030%, P is less than or equal to 0.018%, S is less than or equal to 0.010%, Nb: 0.03-0.04%, N: 0.0050-0.0070% and the balance of Fe and inevitable impurities.
The action mechanism of each chemical component in the steel is as follows:
c: as the carbon content increases, the material yield point and tensile strength gradually increase, but the plasticity and impact toughness decrease. The carbon content therefore needs to be tailored to the different material applications.
Si: the silicon element can obviously improve the elastic limit, the yield point and the tensile strength of the steel, obviously strengthen ferrite, is an essential element for ensuring the strength, and has insufficient over-low strength; too high causes the ferrite matrix to become brittle and the toughness to decrease.
Mn: solid solution formed by manganese and iron improves the hardness and strength of ferrite in the steel; meanwhile, the manganese is an element formed by carbide, enters cementite to replace part of iron atoms, and plays a role in refining pearlite due to the fact that the critical transformation temperature of the manganese in steel is reduced, and also indirectly plays a role in improving the strength of pearlite steel. Manganese is second only to nickel in its ability to stabilize the structure, and also strongly increases the hardenability of steel.
Cr: the alloy elements for reducing the pearlite transformation temperature are added simultaneously, so that the pearlite lamellar spacing can be effectively reduced, and the strength and the toughness of the steel are improved; however, if the Cr content is too high, bainite is easily formed, and the uniformity of the steel structure and hardness is reduced.
N: the most economic and effective alloying elements can form AlN through being combined with Al to strengthen precipitation and refine crystal grain effects; however, when the content of N is too high, more AlN is easily generated to increase the crack sensitivity of a continuous casting billet, and simultaneously, the content and the size of TiN inclusions in steel are increased to damage the toughness of the steel.
Al: the crystal grains are refined by combining with N, so that the toughness is improved; however, too high Al content easily causes poor fluidity during continuous casting, and the continuous casting slab is easy to crack, thereby increasing the smelting difficulty of steel.
S: too high control of the elements may reduce the cleanliness of the steel and deteriorate the properties of the steel.
P: increasing the brittleness of the steel, reducing the impact property, controlling the content of the P element not to exceed 0.018 percent, and preventing the comprehensive performance of the steel from being reduced.
Ni: not only can improve the strength of the steel, but also can improve the plasticity and toughness of the steel. Ni does not form carbide in steel, can only be dissolved in solid state in ferrite, and plays the roles of grain refinement, ferrite strengthening, toughness improvement, especially low-temperature impact toughness performance improvement, and hardenability improvement of steel, and is especially useful for high-strength bolts with higher and uniform mechanical performance requirements.
Nb: a trace amount of niobium may improve the strength of the steel without affecting the plasticity or toughness of the steel. The impact toughness of the steel can be improved and the brittle transition temperature of the steel can be reduced due to the effect of refining grains. The method improves the hardenability and the low-temperature performance of the steel while increasing the hardenability in the carburizing and quenching and tempering alloy structural steel, can reduce the air hardening of the low-carbon martensite heat-resistant stainless steel, avoids hardening and tempering brittleness, and improves the creep strength.
The steel grain size for the bolt is more than or equal to 8.5 grade.
The tensile strength Rm of the steel for the bolt is as follows: 1080-1400 MPa, yield strength σ s: 945-1065 MPa, impact energy Akv2 at-120 ℃ is more than or equal to 47J.
The invention also provides a production method of the high-strength extremely cold environment impact-resistant bolt steel, which comprises the working procedures of smelting, continuous casting, heating, continuous rolling and heat treatment; the heat treatment process adopts an integral quenching and tempering heat treatment process, wherein the normalizing temperature is 850-900 ℃, and the normalizing time is 0.5-1.0 h; the quenching temperature is 850-890 ℃, and the quenching time is 1.0-1.5 h; the tempering temperature is 560-620 ℃ and the tempering time is 2.0-3.5 h.
In the smelting process, alloying is carried out in the converter tapping process to adjust the components to be as follows: c: 0.38-0.45%, Si: 0.15 to 0.35%, Mn: 0.75 to 1.0%, Cr: 0.90-1.20%, Mo: 0.15 to 0.25%, Ni: 0.10 to 0.30%, Al: 0.010-0.035%, P is less than or equal to 0.018%, S is less than or equal to 0.020%, Nb: 0.02-0.05%, N: 0.0040-0.0080%, and the balance of Fe and inevitable impurities; and performing LF refining to fine adjust alloy elements, and feeding 0.1-0.5 kg of aluminum wires per t of steel after VD vacuum degassing treatment.
In the continuous casting process, the chemical components and the mass percentage of the ladle sample in the continuous casting are as follows: c: 0.40 to 0.43%, Si: 0.20 to 0.25%, Mn: 0.85-0.90%, Cr: 1.05-1.10%, Mo: 0.20 to 0.22%, Ni: 0.20 to 0.25%, Al: 0.025-0.030%, P is less than or equal to 0.018%, S is less than or equal to 0.010%, Nb: 0.03-0.04%, N: 0.0050-0.0070% and the balance of Fe and inevitable impurities.
In the heating process, the billet is heated to 930-1080 ℃ and is kept warm for 0.75-1.0 h.
In the continuous rolling process, the initial rolling temperature is 870-970 ℃, and the final rolling temperature is 780-850 ℃; and the rolled material adopts a slow cooling process, and the slow cooling time is 16-36 h.
The high-strength extreme cold environment impact-resistant bolt steel product standard reference GB/T3098.1-2010 is provided; the product performance detection method is in standard reference GB/T2975-2018.
Adopt the produced beneficial effect of above-mentioned technical scheme to lie in: 1. according to the invention, Al is added to form AlN particles, precipitation strengthening and grain refinement are carried out, and the toughness of the steel is not damaged while the strength is improved. 2. By adding Ni and Nb, the invention not only can refine crystal grains and improve the strength of the steel, but also can improve the plasticity and toughness of the steel and reduce the ductile-brittle transition temperature of the steel. 3. The invention adopts the normalizing, quenching and tempering integral quenching and tempering heat treatment process, ensures the impact toughness of the bolt steel in an extremely cold environment and simultaneously has high strength. 4. The invention adopts the production processes of converter smelting, LF refining, VD vacuum degassing treatment, heating, continuous casting, continuous rolling and integral quenching and tempering heat treatment, and the production flow is simple and convenient. 5. The steel for the bolt has the grain size of more than or equal to 8.5 grade, and the tensile strength Rm: 1080-1400 MPa, yield strength σ s: 945-1065 MPa, impact energy Akv2 at-120 ℃ is more than or equal to 47J, and the performance is stable.
Detailed Description
The present invention will be described in further detail with reference to specific examples.
Example 1
The chemical components and the mass percentage of the steel for the high-strength extremely cold environment impact-resistant bolt in the embodiment are shown in table 1.
The production method of the high-strength extremely cold environment impact-resistant bolt steel comprises the working procedures of smelting, continuous casting, heating, continuous rolling and heat treatment, and the specific process steps are as follows:
(1) smelting: alloying is carried out in the tapping process of the converter to adjust the chemical composition and the mass percentage content of the molten steel, which are shown in the table 2; fine adjustment of alloy elements is carried out in LF refining, and 0.33 kg of aluminum wires per t of steel are fed after VD vacuum degassing treatment;
(2) and (3) continuous casting process: the chemical composition and the mass percentage of the continuous casting tundish sample are shown in a table 1;
(3) a heating procedure: heating the steel billet to 930 ℃, and preserving heat for 0.75 h;
(4) a continuous rolling procedure: the initial rolling temperature is 870 ℃, and the final rolling temperature is 840 ℃; the rolled material adopts a slow cooling process, and the slow cooling time is 36 h;
(5) a heat treatment process: adopting an integral quenching and tempering heat treatment process, wherein the normalizing temperature is 850 ℃ and the normalizing time is 0.5 h; the quenching temperature is 870 ℃ and the quenching time is 1.2 h; the tempering temperature is 560 ℃, and the tempering time is 2.3 h.
The properties and grain size of the high-strength extreme cold environment impact-resistant bolt steel of this example are shown in table 3.
Example 2
The chemical components and the mass percentage of the steel for the high-strength extremely cold environment impact-resistant bolt in the embodiment are shown in table 1.
The production method of the high-strength extremely cold environment impact-resistant bolt steel comprises the working procedures of smelting, continuous casting, heating, continuous rolling and heat treatment, and the specific process steps are as follows:
(1) smelting: alloying is carried out in the tapping process of the converter to adjust the chemical composition and the mass percentage content of the molten steel, which are shown in the table 2; fine adjustment of alloy elements is carried out in LF refining, and 0.25 kg of aluminum wires per t of steel are fed after VD vacuum degassing treatment;
(2) and (3) continuous casting process: the chemical composition and the mass percentage of the continuous casting tundish sample are shown in a table 1;
(3) a heating procedure: heating the steel billet to 1080 ℃, and preserving heat for 1 h;
(4) a continuous rolling procedure: the initial rolling temperature is 950 ℃, and the final rolling temperature is 850 ℃; the rolled material adopts a slow cooling process, and the slow cooling time is 24 hours;
(5) a heat treatment process: adopting an integral quenching and tempering heat treatment process, wherein the normalizing temperature is 870 ℃, and the normalizing time is 0.5 h; the quenching temperature is 850 ℃ and the quenching time is 1.4 h; the tempering temperature is 620 ℃ and the tempering time is 3.1 h.
The properties and grain size of the high-strength extreme cold environment impact-resistant bolt steel of this example are shown in table 3.
Example 3
The chemical components and the mass percentage of the steel for the high-strength extremely cold environment impact-resistant bolt in the embodiment are shown in table 1.
The production method of the high-strength extremely cold environment impact-resistant bolt steel comprises the working procedures of smelting, continuous casting, heating, continuous rolling and heat treatment, and the specific process steps are as follows:
(1) smelting: alloying is carried out in the tapping process of the converter to adjust the chemical composition and the mass percentage content of the molten steel, which are shown in the table 2; fine adjustment of alloy elements is carried out in LF refining, and 0.47 kg of aluminum wires per t of steel are fed after VD vacuum degassing treatment;
(2) and (3) continuous casting process: the chemical composition and the mass percentage of the continuous casting tundish sample are shown in a table 1;
(3) a heating procedure: heating the steel billet to 980 ℃, and preserving heat for 1 h;
(4) a continuous rolling procedure: the initial rolling temperature is 900 ℃, and the final rolling temperature is 830 ℃; the rolled material adopts a slow cooling process, and the slow cooling time is 16 h;
(5) a heat treatment process: adopting an integral quenching and tempering heat treatment process, wherein the normalizing temperature is 900 ℃, and the normalizing time is 0.75 h; the quenching temperature is 850 ℃ and the quenching time is 1.3 h; the tempering temperature is 600 ℃, and the tempering time is 2.5 h.
The properties and grain size of the high-strength extreme cold environment impact-resistant bolt steel of this example are shown in table 3.
Example 4
The chemical components and the mass percentage of the steel for the high-strength extremely cold environment impact-resistant bolt in the embodiment are shown in table 1.
The production method of the high-strength extremely cold environment impact-resistant bolt steel comprises the working procedures of smelting, continuous casting, heating, continuous rolling and heat treatment, and the specific process steps are as follows:
(1) smelting: alloying is carried out in the tapping process of the converter to adjust the chemical composition and the mass percentage content of the molten steel, which are shown in the table 2; fine adjustment of alloy elements is carried out in LF refining, and 0.23 kg of aluminum wires per t of steel are fed after VD vacuum degassing treatment;
(2) and (3) continuous casting process: the chemical composition and the mass percentage of the continuous casting tundish sample are shown in a table 1;
(3) a heating procedure: heating the steel billet to 1080 ℃, and preserving heat for 0.75 h;
(4) a continuous rolling procedure: the initial rolling temperature is 890 ℃, and the final rolling temperature is 790 ℃; the rolled material adopts a slow cooling process, and the slow cooling time is 24 hours;
(5) a heat treatment process: adopting an integral quenching and tempering heat treatment process, wherein the normalizing temperature is 870 ℃, and the normalizing time is 0.75 h; the quenching temperature is 890 ℃ and the quenching time is 1.1 h; the tempering temperature is 580 ℃ and the tempering time is 3.3 h.
The properties and grain size of the high-strength extreme cold environment impact-resistant bolt steel of this example are shown in table 3.
Example 5
The chemical components and the mass percentage of the steel for the high-strength extremely cold environment impact-resistant bolt in the embodiment are shown in table 1.
The production method of the high-strength extremely cold environment impact-resistant bolt steel comprises the working procedures of smelting, continuous casting, heating, continuous rolling and heat treatment, and the specific process steps are as follows:
(1) smelting: alloying is carried out in the tapping process of the converter to adjust the chemical composition and the mass percentage content of the molten steel, which are shown in the table 2; fine adjustment of alloy elements is carried out in LF refining, and 0.15 kg of aluminum wires per t of steel are fed after VD vacuum degassing treatment;
(2) and (3) continuous casting process: the chemical composition and the mass percentage of the continuous casting tundish sample are shown in a table 1;
(3) a heating procedure: heating the steel billet to 1000 ℃, and preserving heat for 0.90 h;
(4) a continuous rolling procedure: the initial rolling temperature is 920 ℃, and the final rolling temperature is 830 ℃; the rolled material adopts a slow cooling process, and the slow cooling time is 36 h;
(5) a heat treatment process: adopting an integral quenching and tempering heat treatment process, wherein the normalizing temperature is 870 ℃, and the normalizing time is 1 h; the quenching temperature is 870 ℃ and the quenching time is 1.2 h; the tempering temperature is 580 ℃ and the tempering time is 2.8 h.
The properties and grain size of the high-strength extreme cold environment impact-resistant bolt steel of this example are shown in table 3.
Example 6
The chemical components and the mass percentage of the steel for the high-strength extremely cold environment impact-resistant bolt in the embodiment are shown in table 1.
The production method of the high-strength extremely cold environment impact-resistant bolt steel comprises the working procedures of smelting, continuous casting, heating, continuous rolling and heat treatment, and the specific process steps are as follows:
(1) smelting: alloying is carried out in the tapping process of the converter to adjust the chemical composition and the mass percentage content of the molten steel, which are shown in the table 2; fine adjustment of alloy elements is carried out in LF refining, and 0.27 kg of aluminum wires per t of steel are fed after VD vacuum degassing treatment;
(2) and (3) continuous casting process: the chemical composition and the mass percentage of the continuous casting tundish sample are shown in a table 1;
(3) a heating procedure: heating the steel billet to 1050 ℃, and preserving heat for 0.80 h;
(4) a continuous rolling procedure: the initial rolling temperature is 940 ℃, and the final rolling temperature is 800 ℃; the rolled material adopts a slow cooling process, and the slow cooling time is 16 h;
(5) a heat treatment process: adopting an integral quenching and tempering heat treatment process, wherein the normalizing temperature is 890 ℃, and the normalizing time is 0.75 h; the quenching temperature is 860 ℃, and the quenching time is 1.3 h; the tempering temperature is 610 ℃ and the tempering time is 2.4 h.
The properties and grain size of the high-strength extreme cold environment impact-resistant bolt steel of this example are shown in table 3.
Example 7
The chemical components and the mass percentage of the steel for the high-strength extremely cold environment impact-resistant bolt in the embodiment are shown in table 1.
The production method of the high-strength extremely cold environment impact-resistant bolt steel comprises the working procedures of smelting, continuous casting, heating, continuous rolling and heat treatment, and the specific process steps are as follows:
(1) smelting: alloying is carried out in the tapping process of the converter to adjust the chemical composition and the mass percentage content of the molten steel, which are shown in the table 2; fine adjustment of alloy elements is carried out in LF refining, and 0.10 kg of aluminum wires per t of steel are fed after VD vacuum degassing treatment;
(2) and (3) continuous casting process: the chemical composition and the mass percentage of the continuous casting tundish sample are shown in a table 1;
(3) a heating procedure: heating the steel billet to 1020 ℃, and preserving heat for 0.85 h;
(4) a continuous rolling procedure: the initial rolling temperature is 970 ℃, and the final rolling temperature is 780 ℃; the rolled material adopts a slow cooling process, and the slow cooling time is 20 hours;
(5) a heat treatment process: adopting an integral quenching and tempering heat treatment process, wherein the normalizing temperature is 860 ℃ and the normalizing time is 0.5 h; the quenching temperature is 880 ℃, and the quenching time is 1.0 h; the tempering temperature is 570 ℃ and the tempering time is 3.5 h.
The properties and grain size of the high-strength extreme cold environment impact-resistant bolt steel of this example are shown in table 3.
Example 8
The chemical components and the mass percentage of the steel for the high-strength extremely cold environment impact-resistant bolt in the embodiment are shown in table 1.
The production method of the high-strength extremely cold environment impact-resistant bolt steel comprises the working procedures of smelting, continuous casting, heating, continuous rolling and heat treatment, and the specific process steps are as follows:
(1) smelting: alloying is carried out in the tapping process of the converter to adjust the chemical composition and the mass percentage content of the molten steel, which are shown in the table 2; fine adjustment of alloy elements is carried out in LF refining, and 0.5 kg of aluminum wires per t of steel are fed after VD vacuum degassing treatment;
(2) and (3) continuous casting process: the chemical composition and the mass percentage of the continuous casting tundish sample are shown in a table 1;
(3) a heating procedure: heating the steel billet to 950 ℃, and preserving heat for 0.95 h;
(4) a continuous rolling procedure: the initial rolling temperature is 880 ℃, and the final rolling temperature is 810 ℃; the rolled material adopts a slow cooling process, and the slow cooling time is 30 h;
(5) a heat treatment process: adopting an integral quenching and tempering heat treatment process, wherein the normalizing temperature is 880 ℃, and the normalizing time is 1 h; the quenching temperature is 875 ℃ and the quenching time is 1.5 h; the tempering temperature is 590 ℃, and the tempering time is 2.0 h.
The properties and grain size of the high-strength extreme cold environment impact-resistant bolt steel of this example are shown in table 3.
TABLE 1 EXAMPLES 1-8 chemical composition of steel for high-strength extreme cold environment impact bolt
And mass percentage content (%)
In table 1, the balance is Fe and inevitable impurities.
TABLE 2 examples 1-8 composition of chemical components of molten steel alloyed during tapping in converter
And mass percentage content (%)
In table 2, the balance is Fe and inevitable impurities.
Table 3 test results of properties of high-strength steel for extremely cold environment impact-resistant bolts in examples 1 to 8
Although the present invention has been described in detail with reference to the above embodiments, it should be understood by those skilled in the art that: modifications and equivalents may be made thereto without departing from the spirit and scope of the invention and it is intended to cover in the claims the invention as defined in the appended claims.
Claims (8)
1. The high-strength steel for the bolt resistant to the impact of the extreme cold environment is characterized by comprising the following chemical components in percentage by mass: c: 0.40 to 0.43%, Si: 0.20 to 0.25%, Mn: 0.85-0.90%, Cr: 1.05-1.10%, Mo: 0.20 to 0.22%, Ni: 0.20 to 0.25%, Al: 0.025-0.030%, P is less than or equal to 0.018%, S is less than or equal to 0.010%, Nb: 0.03-0.04%, N: 0.0050-0.0070% and the balance of Fe and inevitable impurities.
2. The steel for high-strength extremely cold environment impact-resistant bolts according to claim 1, wherein the steel for bolts has a grain size of not less than 8.5 grade.
3. The steel for high-strength extremely cold environment impact-resistant bolts according to claim 1, wherein the tensile strength Rm of the steel for bolts is: 1080-1400 MPa, yield strength σ s: 945-1065 MPa, impact energy Akv2 at-120 ℃ is more than or equal to 47J.
4. The production method of the steel for the high-strength extremely cold environment impact-resistant bolt according to any one of claims 1 to 3, characterized by comprising the working procedures of smelting, continuous casting, heating, continuous rolling and heat treatment; the heat treatment process adopts an integral quenching and tempering heat treatment process, wherein the normalizing temperature is 850-900 ℃, and the normalizing time is 0.5-1.0 h; the quenching temperature is 850-890 ℃, and the quenching time is 1.0-1.5 h; the tempering temperature is 560-620 ℃ and the tempering time is 2.0-3.5 h.
5. The method for producing the steel for the high-strength extremely cold environment impact-resistant bolt according to claim 4, wherein the smelting process, the converter tapping process, is performed with alloying to adjust the composition to: c: 0.38-0.45%, Si: 0.15 to 0.35%, Mn: 0.75 to 1.0%, Cr: 0.90-1.20%, Mo: 0.15 to 0.25%, Ni: 0.10 to 0.30%, Al: 0.010-0.035%, P is less than or equal to 0.018%, S is less than or equal to 0.010%, Nb: 0.02-0.05%, N: 0.0040-0.0080%, and the balance of Fe and inevitable impurities; and performing LF refining to fine adjust alloy elements, and feeding 0.1-0.5 kg of aluminum wires per t of steel after VD vacuum degassing treatment.
6. The production method of the steel for the high-strength extremely cold environment impact-resistant bolt according to claim 4, characterized in that the continuous casting process comprises the following chemical components in percentage by mass: c: 0.40 to 0.43%, Si: 0.20 to 0.25%, Mn: 0.85-0.90%, Cr: 1.05-1.10%, Mo: 0.20 to 0.22%, Ni: 0.20 to 0.25%, Al: 0.025-0.030%, P is less than or equal to 0.018%, S is less than or equal to 0.010%, Nb: 0.03-0.04%, N: 0.0050-0.0070% and the balance of Fe and inevitable impurities.
7. The method for producing a high-strength steel for an extremely cold environment impact-resistant bolt according to any one of claims 4 to 6, characterized in that in the heating step, the billet is heated to 930 to 1080 ℃ and is kept warm for 0.75 to 1.0 hour.
8. The production method of the steel for the high-strength extremely cold environment impact-resistant bolt according to any one of claims 4 to 6, characterized in that the continuous rolling process is performed at an initial rolling temperature of 870 to 970 ℃ and a final rolling temperature of 780 to 850 ℃; and the rolled material adopts a slow cooling process, and the slow cooling time is 16-36 h.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112795854A (en) * | 2020-12-23 | 2021-05-14 | 石家庄钢铁有限责任公司 | High-strength fastener bolt steel and production method thereof |
| RU2774760C1 (en) * | 2021-09-08 | 2022-06-22 | Публичное акционерное общество «Северсталь» (ПАО «Северсталь») | Method for production of cold-resistant rolled products |
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| EP2803742A1 (en) * | 2012-01-11 | 2014-11-19 | Kabushiki Kaisha Kobe Seiko Sho | Steel for bolts, bolt, and method for producing bolt |
| CN104975235A (en) * | 2015-07-20 | 2015-10-14 | 江阴兴澄特种钢铁有限公司 | High-toughness medium-carbon quenched and tempered round steel of grade 120 KSI and manufacturing method thereof |
| CN107177797A (en) * | 2017-04-24 | 2017-09-19 | 江阴兴澄特种钢铁有限公司 | The oil gas field anti-corrosion drilling tool steel of 130KSI, 135KSI rank and its manufacture method |
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| EP2803742A1 (en) * | 2012-01-11 | 2014-11-19 | Kabushiki Kaisha Kobe Seiko Sho | Steel for bolts, bolt, and method for producing bolt |
| CN104975235A (en) * | 2015-07-20 | 2015-10-14 | 江阴兴澄特种钢铁有限公司 | High-toughness medium-carbon quenched and tempered round steel of grade 120 KSI and manufacturing method thereof |
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| CN112795854A (en) * | 2020-12-23 | 2021-05-14 | 石家庄钢铁有限责任公司 | High-strength fastener bolt steel and production method thereof |
| RU2774760C1 (en) * | 2021-09-08 | 2022-06-22 | Публичное акционерное общество «Северсталь» (ПАО «Северсталь») | Method for production of cold-resistant rolled products |
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