A high-performance hard wire steel and a method for producing the same

Abstract

The application discloses a kind of high-efficiency hard wire steel and its production method, chemical component composition and its mass percentage are as follows: C:0.30~0.60%, Mn:0.50~0.80%, S≤0.020%, P≤0.020%, Si:0.17~0.37%, Cr, Ni, Cu≤0.025%, N≤0.0045%.The balance is Fe and inevitable impurities;Production method includes converter smelting, post-furnace argon blowing, bloom continuous casting process, straight rolling roller conveying, hot rolling wire drawing, air cooling packing.The application adopts tundish argon blowing in continuous casting, adopts stirring technology in crystallizer, improves the purity of molten steel, eliminates the center shrinkage hole and center segregation of continuous casting billet, adopts heating-free straight rolling technology to produce φ5.0-10.0mm specification wire product, and realizes the production of high-efficiency hard wire steel.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, specifically relating to a high-efficiency hard wire steel and its production method. Background Technology

[0002] Hard wire rod, a common type of high-quality carbon steel wire rod, is widely used in cement nails, galvanized iron wire, umbrella frames, wire ropes, springs, shot blasting steel balls, rubber belt wire, tire bead wire, and steel strand. The product has a wide range of applications, with large and stable demand. Conventional steelmaking processes involve converters, refining, and continuous casting. During alloy adjustment and heating, molten steel is prone to regenerating inclusions. Simultaneously, electrode heating generates nitrogen through ionization, increasing the content of harmful gases in the molten steel. The long steelmaking process results in prolonged residence time of molten steel in the ladle, which can corrode the refractory lining and introduce foreign inclusions. After billet production, the billets undergo stacking, centralized loading, and heating / rolling processes. Cooling and reheating of the billets leads to the formation of a large amount of iron oxide scale on the surface, resulting in burn-off and waste of metal and raw materials. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a high-efficiency hard wire steel and its production method, which has the characteristics of short process, low cost and good quality.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0005] A high-efficiency hard wire steel, wherein the chemical composition and mass percentage of the hard wire steel are as follows: C: 0.30-0.60%, Mn: 0.50-0.80%, S≤0.020%, P≤0.020%, Si: 0.17-0.37%, Cr, Ni, and Cu are all ≤0.025%, N≤0.0045%, and the balance is Fe and unavoidable impurities.

[0006] Preferably, the steel used for the hard wire has a diameter of φ5~10mm and a microstructure of ferrite + pearlite.

[0007] Preferably, the mechanical properties of the hard wire steel are Rm≤1000MPa and elongation A≥10%.

[0008] A method for producing high-efficiency hard wire steel includes converter smelting, post-furnace argon blowing, billet continuous casting, straight rolling mill roller conveying, hot rolling, and air-cooled packaging processes.

[0009] In the billet continuous casting process, the superheat of molten steel in the tundish is 15-30℃, the casting speed of the continuous casting machine is controlled at 2.3-2.8m / min, the melting point of the protective slag used in the crystallizer is 950-1030℃, the basicity is 0.85-1.00, the viscosity is 0.75-0.85P·S, the secondary cooling adopts weak cooling, and the specific water content is 0.9-1.2L / kg steel.

[0010] Preferably, the billet continuous casting process employs argon blowing in the tundish and stirring technology in the crystallizer. Argon is blown at the tundish top nozzle and between plates, with an argon flow rate of 1-3 NL / min. The crystallizer uses electromagnetic stirring + end electromagnetic stirring technology. The electromagnetic stirring parameters are: current 390-450A, frequency 2-3.5Hz; the end electromagnetic stirring parameters are: current 330-350A, frequency 6-10Hz.

[0011] Preferably, in the converter smelting process, the S content in the molten iron fed into the furnace is ≤0.025%, and the P content is ≤0.120%; lime and lightly calcined dolomite are used for slag formation, with 30-50 kg / t of lime and 20-25 kg / t of lightly calcined dolomite added; the converter endpoint is: carbon content C ≥0.10%, phosphorus content P ≤0.015%, and sulfur content S ≤0.015%; argon is blown throughout the converter bottom blowing process, and a sliding plate is used to block slag after the furnace to reduce the amount of slag carried over. During the tapping process, 3-5 kg / t of lime, 1-3 kg / t of wollastonite, and 1-1.5 kg / t of fluorite are added; after the furnace, silicon-manganese alloy, high-carbon ferromanganese, carbon powder, and silicon-barium-calcium-iron deoxidizer are added.

[0012] Preferably, in the post-furnace argon blowing process, the carbon content is adjusted according to the bulk composition of the carbon feed line; the static blowing time is ≥15 minutes, and the outlet temperature of the argon blowing station is 1570~1595℃.

[0013] Preferably, in the post-furnace argon blowing process, the chemical composition and mass percentage of the molten steel leaving the argon blowing station are controlled as follows: C: 0.30-0.60%, Mn: 0.50-0.80%, S≤0.020%, P≤0.020%, Si: 0.17-0.37%, Cr, Ni, and Cu are all ≤0.025%, N≤0.0045%, and the balance is Fe and unavoidable impurities.

[0014] Preferably, the hot rolling process employs a direct rolling technology without heating, eliminating the need for billet heating and reducing surface decarburization and iron loss. The billet is rapidly transported to the mill entrance via a direct rolling ramp with an insulation cover. The direct rolling ramp conveyor speed is 2.5-3.6 m / s; the roughing rolling start temperature is 950-1000℃; the billet is rolled by a 6+6+6 arrangement of roughing-intermediate-finishing mills, with a final rolling speed of 80-110 m / s and a wire drawing temperature of 860-900℃. After passing through an air-cooled roller conveyor, wire rod products with a diameter of φ5-10 mm are obtained.

[0015] This invention uses a converter-billet continuous casting-hot wire rod direct rolling process to produce hard wire steel. The product uses C, Si, and Mn as strengthening elements, and controls the content of elements such as S, P, and N.

[0016] The use of electromagnetic stirring technology in the crystallizer effectively improves the quality of continuously cast billets; the use of direct rolling technology without heating avoids energy consumption and iron burning during the heating and cooling process of the billets, while effectively reducing surface decarburization of the billets and ensuring the surface decarburization depth of the finished wire rods. This invention successfully produces hard wire steel with a specification of φ5~10mm. The production method of this invention has the characteristics of short process, low cost and good quality.

[0017] This invention, from a holistic process perspective, employs a converter + continuous casting + direct rolling process for unheated billets. This simplifies the types of strengthening alloying elements, reduces steel refining steps, lowers the risk of recycled inclusions, and reduces the content of harmful gases in the steel. It also reduces the billet heating process by using unheated direct rolling technology, thus reducing energy consumption and metal loss. This invention develops a low-cost, high-purity, high-efficiency hard wire steel with a short process, which is of positive significance for energy conservation, emission reduction, and achieving carbon neutrality goals in the steel industry.

[0018] The beneficial effects of adopting the above technical solution are as follows:

[0019] 1. This invention is designed for the composition and process path of 60# and below hard wire steel, which is widely used in the current market. The subsequent processing technology of 60# and below hard wire steel can be fully satisfied.

[0020] 2. This invention uses a converter-continuous casting direct process, with a post-furnace argon blowing station to homogenize the composition and ensure thorough removal of inclusions. This can effectively reduce heat loss in the steelmaking process, reduce the residence time of molten steel in the ladle, and reduce refractory corrosion and foreign inclusions.

[0021] 3. This invention uses Si deoxidation. By controlling the Si content, the active oxygen content at the refined outlet is guaranteed, the level of inclusions is controlled, and the drawing performance of the welding wire is guaranteed.

[0022] 4. This invention employs crystallizer electric stirring + end stirring technology, which can effectively eliminate central shrinkage cavities and segregation in the cast billet.

[0023] 5. This invention adopts a billet continuous casting-hot rolling process and a direct rolling technology without heating. There is no billet heating step, which reduces the surface decarburization of the billet and the loss of metallic iron, and ensures the surface decarburization depth of the finished wire rod.

[0024] 6. This invention ensures a uniform pearlite + ferrite microstructure by controlling the final rolling speed, wire drawing temperature, and roller cooling, thereby achieving low-cost and high-efficiency production of hard wire. Attached Figure Description

[0025] Figure 1 This is a low-magnification microstructure diagram of the billet in Example 1;

[0026] Figure 2 The metallographic structure of the steel used for hard wire in Example 1 is shown in the figure (200×). Detailed Implementation

[0027] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0028] Example 1

[0029] The diameter of the hard wire steel product in this embodiment is φ5.0mm, and its chemical composition and mass percentage are shown in Table 1.

[0030] The production method for hard wire steel products in this embodiment includes converter smelting, post-furnace argon blowing, billet continuous casting, hot rolling, and roller cooling and packaging processes. The specific production process steps are as follows:

[0031] (1) Converter smelting: S: 0.005% and P: 0.110% in the molten iron; lime and lightly calcined dolomite are used for slag formation, with 30 kg / t of lime and 20 kg / t of lightly calcined dolomite added;

[0032] Converter endpoint: C: 0.11%, P: 0.009%; when 1 / 4 of the steel is tapped, first add 4.5 kg / t of lime, 2.5 kg / t of wollastonite, and 1.4 kg / t of fluorite, and at the same time add 0.4 kg / t of deoxidizer silicon barium calcium iron. The alloying operation is carried out thereafter. All the additions must be completed before 3 / 4 of the steel is tapped. The order and amount of addition are shown in Table 2.

[0033] (2) Argon blowing after furnace: Argon gas stirring and static blowing time is 18 min, and the outlet temperature is 1593℃; the chemical composition and mass percentage of the molten steel leaving the argon blowing station are shown in Table 1.

[0034] (3) Billet continuous casting process: The superheat of molten steel in the tundish is 30℃, the casting speed of the continuous casting machine is controlled at 2.3m / min, the melting point of the protective slag used in the crystallizer is 1000℃, the basicity is 0.95, the viscosity is 0.85P·S, the secondary cooling adopts weak cooling, and the specific water volume is 0.9L / kg steel. The argon flow rate at the nozzle and plate is 1NL / min. The crystallizer electromagnetic stirring + end stirring technology is used to stir the inside of the billet (electromagnetic stirring parameters: current 390A, frequency 3.5Hz; end electromagnetic stirring parameters: current 330A, frequency 6Hz).

[0035] (4) Hot rolling process: Straight rolling mill conveyor speed: 3.6m / s, rough rolling open billet head temperature 970℃, from 150×150mm 2 The billet is rolled in 18 roughing-medium-finishing passes with a final rolling speed of 110 m / s and a wire drawing temperature of 860℃.

[0036] Figure 1 This is a low-magnification microstructure diagram of the cast billet obtained in Example 1. Figure 1 It is evident that the billet is of good quality, with central shrinkage cavities and no central segregation. Figure 2 The image shows the metallographic structure (200×) of the hard wire steel obtained in Example 1. Figure 2 As can be seen, the microstructure consists of ferrite and pearlite, and is fine and uniform. (The accompanying drawings for Examples 2-5 are similar to those for Example 1, and are therefore omitted.)

[0037] Example 2

[0038] The steel product used for hard wire in this embodiment has a diameter of φ10.0mm, and its chemical composition and mass percentage are shown in Table 1.

[0039] The production method for hard wire steel products in this embodiment includes converter smelting, post-furnace argon blowing, billet continuous casting, hot rolling, and roller cooling and packaging processes. The specific production process steps are as follows:

[0040] (1) Converter smelting: S: 0.007% and P: 0.105% in the molten iron; lime and lightly calcined dolomite are used for slag formation, with 50 kg / t of lime and 25 kg / t of lightly calcined dolomite added;

[0041] Converter endpoint: C: 0.12%, P: 0.011%; when 1 / 4 of the steel is tapped, first add 4.5 kg / t of lime, 2.5 kg / t of wollastonite, and 1.4 kg / t of fluorite, and at the same time add 0.4 kg / t of deoxidizer silicon barium calcium iron. The alloying operation is carried out thereafter. All the additions must be completed before 3 / 4 of the steel is tapped. The order and amount of addition are shown in Table 2.

[0042] (2) Argon blowing after furnace: Argon gas stirring and static blowing time is 15 min, and the outlet temperature is 1572℃; the chemical composition and mass percentage of the molten steel leaving the argon blowing station are shown in Table 1.

[0043] (3) Billet continuous casting process: The superheat of molten steel in the tundish is 15℃, the casting speed of the continuous casting machine is controlled at 2.8m / min, the melting point of the protective slag used in the crystallizer is 950℃, the basicity is 0.95, the viscosity is 0.75P·S, the secondary cooling adopts weak cooling, and the specific water volume is 1.2L / kg steel. The argon flow rate at the nozzle and plate is 3NL / min. The crystallizer electromagnetic stirring + end stirring technology is used to stir the inside of the billet (electromagnetic stirring parameters: current 400A, frequency 3.5Hz; end electromagnetic stirring parameters: current 350A, frequency 6Hz).

[0044] (4) Hot rolling process: Straight rolling mill conveyor speed: 3.6m / s, rough rolling open billet head temperature 1000℃, from 150×150mm 2 The billet is rolled in 18 roughing-medium-finishing passes with a final rolling speed of 86 m / s and a wire drawing temperature of 898℃.

[0045] Example 3

[0046] The steel product used for hard wire in this embodiment has a diameter of φ6.0mm, and its chemical composition and mass percentage are shown in Table 1.

[0047] The production method for hard wire steel products in this embodiment includes converter smelting, post-furnace argon blowing, billet continuous casting, hot rolling, and roller cooling and packaging processes. The specific production process steps are as follows:

[0048] (1) Converter smelting: S: 0.011% and P: 0.115% in the molten iron; lime and lightly calcined dolomite are used for slag formation, with 35 kg / t of lime and 22 kg / t of lightly calcined dolomite added;

[0049] Converter endpoint: C: 0.13%, P: 0.012%; when 1 / 4 of the steel is tapped, first add 3.0 kg / t of lime, 1.0 kg / t of wollastonite, and 1.0 kg / t of fluorite, and at the same time add 0.4 kg / t of deoxidizer silicon barium calcium iron. The alloying operation is carried out thereafter. All the additions must be completed before 3 / 4 of the steel is tapped. The order and amount of addition are shown in Table 2.

[0050] (2) Argon blowing after furnace: Argon gas stirring and static blowing time is 19 min, and the outlet temperature is 1588℃; the chemical composition and mass percentage of the molten steel leaving the argon blowing station are shown in Table 1.

[0051] (3) Billet continuous casting process: The superheat of molten steel in the tundish is 22℃, the casting speed of the continuous casting machine is controlled at 2.5m / min, the melting point of the protective slag used in the crystallizer is 980℃, the basicity is 1.0, the viscosity is 0.85P·S, the secondary cooling adopts intermediate cooling, and the specific water volume is 1.1L / kg steel. The argon flow rate at the nozzle and between plates is 2NL / min. The crystallizer electromagnetic stirring + end stirring technology is used to stir the inside of the billet (electromagnetic stirring parameters: current 390A, frequency 3.5Hz; end electromagnetic stirring parameters: current 330A, frequency 6Hz).

[0052] (4) Hot rolling process: Straight rolling mill conveyor speed: 3.4 m / s, rough rolling open billet head temperature 980℃, from 150×150 mm 2 The billet is rolled in 18 roughing-medium-finishing passes with a final rolling speed of 89 m / s and a wire drawing temperature of 890℃.

[0053] Example 4

[0054] The diameter of the hard wire steel product in this embodiment is φ7.0mm, and its chemical composition and mass percentage are shown in Table 1.

[0055] The production method for hard wire steel products in this embodiment includes converter smelting, post-furnace argon blowing, billet continuous casting, hot rolling, and roller cooling and packaging processes. The specific production process steps are as follows:

[0056] (1) Converter smelting: S: 0.006%, P: 0.110% in the molten iron; lime and lightly calcined dolomite are used for slag making, with 40 kg / t of lime and 23 kg / t of lightly calcined dolomite added;

[0057] Converter endpoint: C: 0.13%, P: 0.013%; when 1 / 4 of the steel is tapped, first add 3.5 kg / t of lime, 2.0 kg / t of wollastonite, and 1.1 kg / t of fluorite, and at the same time add 0.4 kg / t of deoxidizer silicon barium calcium iron. The alloying operation is carried out thereafter. All the additions must be completed before 3 / 4 of the steel is tapped. The order and amount of addition are shown in Table 2.

[0058] (2) Argon blowing after furnace: Argon gas stirring and static blowing time is 22 min, and the outlet temperature is 1582℃; the chemical composition and mass percentage of the molten steel leaving the argon blowing station are shown in Table 1.

[0059] (3) Billet continuous casting process: The superheat of molten steel in the tundish is 26℃, the casting speed of the continuous casting machine is controlled at 2.6m / min, the melting point of the protective slag used in the crystallizer is 1000℃, the basicity is 0.95, and the viscosity is 0.85P·S. Secondary cooling is carried out by intermediate cooling, and the specific water volume is 1.0L / kg steel. The argon flow rate at the nozzle and between plates is 2NL / min. The crystallizer electromagnetic stirring + end stirring technology is used to stir the inside of the billet (electromagnetic stirring parameters: current 400A, frequency 2Hz; end electromagnetic stirring parameters: current 350A, frequency 7Hz).

[0060] (4) Hot rolling process: Straight rolling mill conveyor speed: 3.1m / s, roughing mill open rolling billet head temperature 985℃, from 150×150mm 2 The billet is rolled in 18 roughing-medium-finishing passes with a final rolling speed of 97 m / s and a wire drawing temperature of 892℃.

[0061] Example 5

[0062] The diameter of the hard wire steel product in this embodiment is φ8.0mm, and its chemical composition and mass percentage are shown in Table 1.

[0063] The production method for hard wire steel products in this embodiment includes converter smelting, post-furnace argon blowing, billet continuous casting, hot rolling, and roller cooling and packaging processes. The specific production process steps are as follows:

[0064] (1) Converter smelting: S: 0.003% and P: 0.113% in the molten iron; lime and lightly calcined dolomite are used for slag formation, with 42 kg / t of lime and 20 kg / t of lightly calcined dolomite added;

[0065] Converter endpoint: C: 0.12%, P: 0.012%; when 1 / 4 of the steel is tapped, first add 4.5 kg / t of lime, 2.0 kg / t of wollastonite, and 1.2 kg / t of fluorite, and at the same time add 0.4 kg / t of deoxidizer silicon barium calcium iron. The alloying operation is carried out thereafter. All the additions must be completed before 3 / 4 of the steel is tapped. The order and amount of addition are shown in Table 2.

[0066] (2) Argon blowing after furnace: Argon gas stirring and static blowing time is 20 min, and the outlet temperature is 1576℃; the chemical composition and mass percentage of the molten steel leaving the argon blowing station are shown in Table 1.

[0067] (3) Billet continuous casting process: The superheat of molten steel in the tundish is 25℃, the casting speed of the continuous casting machine is controlled at 2.7m / min, the melting point of the protective slag used in the crystallizer is 1030℃, the basicity is 0.85, and the viscosity is 0.80P·S. Secondary cooling is carried out by intermediate cooling, and the specific water volume is 1.1L / kg steel. The argon flow rate at the nozzle and between plates is 2NL / min. The crystallizer electromagnetic stirring + end stirring technology is used to stir the inside of the billet (electromagnetic stirring parameters: current 390A, frequency 3.5Hz; end electromagnetic stirring parameters: current 330A, frequency 6Hz).

[0068] (4) Hot rolling process: Straight rolling mill conveyor speed: 3.6m / s, rough rolling open billet head temperature 965℃, from 150×150mm 2 The billet is rolled in 18 roughing-medium-finishing passes with a final rolling speed of 80 m / s and a wire drawing temperature of 885℃.

[0069] Example 6

[0070] The diameter of the hard wire steel product in this embodiment is φ9.0mm, and its chemical composition and mass percentage are shown in Table 1.

[0071] The production method for hard wire steel products in this embodiment includes converter smelting, post-furnace argon blowing, billet continuous casting, hot rolling, and roller cooling and packaging processes. The specific production process steps are as follows:

[0072] (1) Converter smelting: S: 0.005%, P: 0.117% in the molten iron; lime and lightly calcined dolomite are used for slag formation, with 45 kg / t of lime and 21 kg / t of lightly calcined dolomite added;

[0073] Converter endpoint: C: 0.10%, P: 0.009%; when 1 / 4 of the steel is tapped, first add 5.0 kg / t of lime, 3.0 kg / t of wollastonite, and 1.5 kg / t of fluorite, and at the same time add 0.4 kg / t of deoxidizer silicon barium calcium iron. The alloying operation is carried out thereafter. All the additions must be completed before 3 / 4 of the steel is tapped. The order and amount of addition are shown in Table 2.

[0074] (2) Argon blowing after furnace: Argon gas stirring and static blowing time is 17 min, and the outlet temperature is 1579℃; the chemical composition and mass percentage of the molten steel leaving the argon blowing station are shown in Table 1.

[0075] (3) Billet continuous casting process: The superheat of molten steel in the tundish is 27℃, the casting speed of the continuous casting machine is controlled at 2.6m / min, the melting point of the protective slag used in the crystallizer is 1000℃, the basicity is 0.95, the viscosity is 0.85P·S, the secondary cooling adopts intermediate cooling, and the specific water volume is 0.9L / kg steel. The argon flow rate at the nozzle and plate is 2NL / min. The crystallizer electromagnetic stirring + end stirring technology is used to stir the inside of the billet (electromagnetic stirring parameters: current 450A, frequency 3.5Hz; end electromagnetic stirring parameters: current 330A, frequency 6Hz).

[0076] (4) Hot rolling process: Straight rolling mill conveyor speed: 2.5m / s, rough rolling open billet head temperature 990℃, from 150×150mm 2 The billet is rolled in 18 roughing-medium-finishing passes with a final rolling speed of 93 m / s and a wire drawing temperature of 900℃.

[0077] Example 7

[0078] The steel product used for hard wire in this embodiment has a diameter of φ6.0mm, and its chemical composition and mass percentage are shown in Table 1.

[0079] The production method for hard wire steel products in this embodiment includes converter smelting, post-furnace argon blowing, billet continuous casting, hot rolling, and roller cooling and packaging processes. The specific production process steps are as follows:

[0080] (1) Converter smelting: S: 0.008% and P: 0.112% in the molten iron; lime and lightly calcined dolomite are used for slag formation, with 45 kg / t of lime and 23 kg / t of lightly calcined dolomite added;

[0081] Converter endpoint: C: 0.12%, P: 0.012%; when 1 / 4 of the steel is tapped, first add 3.5 kg / t of lime, 1.9 kg / t of wollastonite, and 1.2 kg / t of fluorite, and at the same time add 0.4 kg / t of deoxidizer silicon barium calcium iron. The alloying operation is carried out thereafter. All the additions must be completed before 3 / 4 of the steel is tapped. The order and amount of addition are shown in Table 2.

[0082] (2) Argon blowing after furnace: Argon gas stirring and static blowing time is 18 min, and the outlet temperature is 1573℃; the chemical composition and mass percentage of the molten steel leaving the argon blowing station are shown in Table 1.

[0083] (3) Billet continuous casting process: The superheat of molten steel in the tundish is 23℃, the casting speed of the continuous casting machine is controlled at 2.6m / min, the melting point of the protective slag used in the crystallizer is 1000℃, the basicity is 0.95, the viscosity is 0.85P·S, the secondary cooling adopts intermediate cooling, and the specific water volume is 0.9L / kg steel. The argon flow rate at the nozzle and plate is 2NL / min. The crystallizer electromagnetic stirring + end stirring technology is used to stir the inside of the billet (electromagnetic stirring parameters: current 390A, frequency 3.5Hz; end electromagnetic stirring parameters: current 330A, frequency 10Hz).

[0084] (4) Hot rolling process: Straight rolling mill conveyor speed: 3.6m / s, rough rolling open billet head temperature 950℃, from 150×150mm 2 The billet is rolled in 18 roughing-medium-finishing passes with a final rolling speed of 94 m / s and a wire drawing temperature of 878℃.

[0085] Table 1. Chemical composition and mass percentage (%) of the hard wire steel used in Examples 1-7

[0086]

[0087] In Table 1, the chemical composition balance is Fe and unavoidable impurities.

[0088] Table 2. Post-furnace feeding details (kg / t) in Examples 1-7

[0089]

[0090] Table 3 Mechanical properties of hard wire steel in Examples 1-7

[0091]

[0092] The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A high-efficiency hard wire steel, characterized in that, The chemical composition and mass percentage of the steel used for hard wire are as follows: C: 0.30-0.60%, Mn: 0.50-0.80%, S≤0.020%, P≤0.020%, Si: 0.17-0.37%, Cr, Ni, and Cu are all ≤0.025%, N≤0.0045%, and the balance is Fe and unavoidable impurities.

2. The high-efficiency hard wire steel according to claim 1, characterized in that, The steel used for the hard wire has a diameter of φ5~10mm and a microstructure of ferrite + pearlite.

3. The high-efficiency hard wire steel according to claim 1, characterized in that, The mechanical properties of the hard wire steel are Rm≤1000MPa and elongation A≥10%.

4. A method for producing high-efficiency hard wire steel according to any one of claims 1-3, characterized in that, This includes converter smelting, post-furnace argon blowing, billet continuous casting, straight rolling mill roller conveyor, hot rolling, and air-cooled packaging processes; In the billet continuous casting process, the superheat of molten steel in the tundish is 15-30℃, the casting speed of the continuous casting machine is controlled at 2.3-2.8m / min, the melting point of the protective slag used in the crystallizer is 950-1030℃, the basicity is 0.85-1.00, the viscosity is 0.75-0.85P·S, the secondary cooling adopts weak cooling, and the specific water content is 0.9-1.2L / kg steel.

5. The method for producing high-efficiency hard wire steel according to claim 4, characterized in that, The billet continuous casting process employs argon blowing in the tundish and stirring technology in the crystallizer. Argon is blown at the tundish nozzle and between plates, with an argon flow rate of 1-3 NL / min. The crystallizer uses electromagnetic stirring + end electromagnetic stirring technology. The electromagnetic stirring parameters are: current 390-450A, frequency 2-3.5Hz; the end electromagnetic stirring parameters are: current 330-350A, frequency 6-10Hz.

6. The method for producing high-efficiency hard wire steel according to claim 4, characterized in that, The converter smelting process has the following parameters: S≤0.025% and P≤0.120% in the molten iron; lime and lightly calcined dolomite are used for slag formation, with 30-50 kg / t of lime and 20-25 kg / t of lightly calcined dolomite added; the converter endpoint is: carbon content C≥0.10%, phosphorus content P≤0.015%, and sulfur content S≤0.015%; argon is blown throughout the bottom blowing process of the converter, and slag is blocked by a sliding plate at the back of the furnace; 3-5 kg / t of lime, 1-3 kg / t of wollastonite, and 1-1.5 kg / t of fluorite are added during the tapping process; silicon-manganese alloy, high-carbon ferromanganese, carbon powder, and silicon-barium-calcium-iron deoxidizer are added after the furnace.

7. The method for producing high-efficiency hard wire steel according to claim 4, characterized in that, The post-furnace argon blowing process involves adjusting the carbon content of the carbon feeding line according to the bulk composition; the static blowing time is ≥15 minutes, and the outlet temperature of the argon blowing station is 1570~1595℃.

8. The method for producing high-efficiency hard wire steel according to claim 4, characterized in that, The post-furnace argon blowing process controls the chemical composition and mass percentage of the molten steel leaving the argon blowing station as follows: C: 0.30–0.60%, Mn: 0.50–0.80%, S≤0.020%, P≤0.020%, Si: 0.17–0.37%, Cr, Ni, and Cu all ≤0.025%, N≤0.0045%, with the balance being Fe and unavoidable impurities.

9. The method for producing high-efficiency hard wire steel according to claim 4, characterized in that, The hot rolling process adopts a direct rolling technology without heating. The billet is quickly transported to the mill entrance through a direct rolling climbing roller conveyor with a heat insulation cover. The conveying speed of the direct rolling roller conveyor is 2.5-3.6 m / s. The roughing rolling temperature is 950-1000℃; the final rolling speed is 80-110 m / s; the wire drawing temperature is 860-900℃; and the wire products with a diameter of φ5-10mm are obtained through the air-cooled roller conveyor.

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