High-carbon steel wire rod and wire rod with long fatigue life and manufacturing method of high-carbon steel wire rod and wire rod

Abstract

The invention discloses a high-carbon steel wire rod with long fatigue life, which contains Fe and inevitable impurities, and further contains the following chemical elements in percentage by mass: 0.80 to 0.85 percent of C, 0.20 to 0.30 percent of Si, 0.70 to 0.80 percent of Mn, 0.01 to 0.02 percent of Ni, 0.10 to 0.20 percent of Cr, 0.01 to 0.03 percent of Nb, 0.01 to 0.03 percent of V, 0.003 to 0.007 percent of Ce and the balance of Fe. The volume content of sorbite in the microstructure is higher than 95%, and the lamellar spacing of the sorbite is 80-200 nm. Correspondingly, the invention further discloses a wire rod prepared from the high-carbon steel wire rod and a manufacturing method of the high-carbon steel wire rod and the wire rod.

Description

Technical Field

[0001] The invention relates to a hot-rolled wire rod and a manufacturing method thereof, and in particular to a high-carbon steel wire rod and a manufacturing method thereof. Background Art

[0002] As hard wire steel, high carbon steel is widely used in important fields such as home appliances, railways, bridges, and construction. After heat treatment or cold drawing, high carbon steel can have high strength and hardness, high elastic limit and fatigue limit, and can be used to make various high-stress mechanical springs, piano wires, and high-strength prestressed steel strands. Among them, when high carbon steel is used in the manufacture of piano wires and mechanical springs, high fatigue strength is required, and multiple drawing passes are required before the springs are made, so there are high requirements for the processing performance and fatigue performance of the wire rod.

[0003] In the existing high carbon steel wire production process, the strength and structure of the wire rod are often guaranteed by alloy composition design. While controlling the content of strengthening elements C, Si, Mn, and Cr, at least one element among Al, V, Nb and Ti is selectively added and its content is controlled to refine the grains and troostite lamellae. However, the addition of Al and Ti elements will lead to the production of Al and Ti inclusions, which will increase the problem of wire breakage during processing and the fatigue performance will not meet the requirements.

[0004] The Chinese patent document with publication number CN114622071A and publication date June 14, 2022, entitled "A medium carbon steel with uniform grain structure and its production process" relates to a medium carbon steel hot-rolled wire rod, which adopts a two-stage heating method with a heating time controlled at 150-200 minutes. The improvement mechanism is high-temperature heating of the steel billet to homogenize the structure, large rolling reduction, and post-rolling temperature control. However, the patent document does not solve the fatigue performance of high-carbon steel wire. Summary of the invention

[0005] One of the purposes of the present invention is to provide a high-carbon steel wire rod with high fatigue life. The high-carbon steel wire rod has high tensile strength and high area reduction rate. After cold drawing, the wire rod can be used to make piano wire and mechanical spring wire with high fatigue life requirements.

[0006] In order to achieve the above object, the present invention provides a high carbon steel wire rod with high fatigue life, which contains Fe and inevitable impurities, and further contains the following chemical elements in the following mass percentages:

[0007] C: 0.80~0.85%, Si: 0.20~0.30%, Mn: 0.70~0.80%, Ni: 0.01~0.02%, Cr: 0.10~0.20%, Nb: 0.01~0.03%, V: 0.01~0.03%, Ce: 0.003~0.007%;

[0008] The volume content of troostite in its microstructure is higher than 95%, and the spacing between troostite lamellae is 80-200nm.

[0009] Correspondingly, the present invention also provides a high-carbon steel wire rod with a high fatigue life, the mass percentage of chemical elements of which is:

[0010] C: 0.80-0.85%, Si: 0.20-0.30%, Mn: 0.70-0.80%, Ni: 0.01-0.02%, Cr: 0.10-0.20%, Nb: 0.01-0.03%, V: 0.01-0.03%, Ce: 0.003-0.007%; the balance is Fe and unavoidable impurities;

[0011] The volume content of troostite in its microstructure is higher than 95%, and the spacing between troostite lamellae is 80-200nm.

[0012] The high carbon steel wire rod described in the present invention obtains a high and uniform troostite content by strictly controlling the content of impurity Al and Ti elements, and adding V, Nb and rare earth elements to refine grains and troostite lamellae, and makes the spacing between troostite lamellae extremely small, reaching 80 to 200 nm, thereby achieving excellent strength and toughness matching.

[0013] Specifically, in the high carbon steel wire rod of the present invention, the design principles of each chemical element are as follows:

[0014] C: The C element is an important element to ensure the strength of steel. As the carbon content increases, the yield strength and tensile strength of the material increase, but the plasticity decreases. When the carbon content is too low, the strength and hardness of the material are difficult to meet the requirements; if the carbon content is too high, it will affect the plasticity and toughness of the steel. For high-carbon hard wire steel, the carbon content determines the content of cementite lamellae in the troostite structure. As the carbon content increases, the cementite content gradually increases, but if the carbon content is too high, it is easy to cause component segregation and abnormal structures such as network carbides during the smelting process, resulting in a decrease in plasticity and toughness. Therefore, the mass percentage of the carbon element in the present invention is controlled between 0.80 and 0.85%.

[0015] Si: The high carbon steel wire rod described in the present invention is mainly used to make piano wire and mechanical springs. The Si element can play a role of solid solution strengthening, which can improve the strength of steel and significantly improve the elastic limit of steel. Silicon can also be used as a reducing agent and deoxidizer in the steelmaking process. However, too high a content of Si will affect toughness, make continuous casting difficult, increase the difficulty of forming, and form a large amount of oxide scale on the surface during hot rolling, resulting in poor surface quality of the material. Therefore, the mass percentage of Si in the present invention is controlled between 0.20 and 0.30%.

[0016] Mn: In the high carbon steel wire rod described in the present invention, Mn element is often used as a good deoxidizer and desulfurizer in the steelmaking process. At the same time, Mn element can also play a role in solid solution strengthening, which can make the steel have higher strength and hardness, effectively improve the hardenability of the steel, improve the hot working performance of the steel, and also form manganese sulfide inclusions with S element in the steel to reduce the influence of harmful element sulfur on the steel. However, when Mn element is added too much, it will cause organizational segregation. Therefore, the mass percentage of Mn element in the present invention is controlled between 0.70 and 0.80%.

[0017] Ni: In the high carbon steel wire rod described in the present invention, the Ni element can refine the cementite lamellar structure, improve the wire rod drawing performance, increase the strength of the steel while maintaining good plasticity and toughness, and can improve the corrosion resistance and fatigue performance of the steel. However, the cost of the Ni element is relatively high. Therefore, the mass percentage of the Ni element in the present invention is controlled between 0.01 and 0.02%.

[0018] Cr: In the high carbon steel wire rod described in the present invention, the Cr element can improve the stability of austenite, refine the troostite lamellar structure, and also has the effect of improving the strength. At the same time, it can also improve the wear resistance and corrosion resistance of the steel. Therefore, the mass percentage of the Cr element in the present invention is controlled between 0.10 and 0.20%.

[0019] Nb, V: Nb and V are added to the steel as composite microalloying elements in the present invention. As strong carbide-forming elements, they are very easy to combine with carbon and nitrogen to form carbonitrides. The precipitates have very high melting points, high hardness and stable properties. Niobium vanadium carbides are generally small grains and are easy to precipitate at the grain boundaries, pinning the grain boundaries. Because of their high melting points, they cannot melt into the matrix, which can effectively prevent the growth of matrix grains and effectively refine the grains, playing the role of precipitation strengthening and fine grain strengthening, which can improve the strength of steel while maintaining the plastic toughness without decreasing. Based on this, the contents of Nb and V in the present invention are controlled between 0.01 and 0.03%.

[0020] Ce: The addition of rare earth elements can purify the molten steel, reduce the oxygen and sulfur content, and react with harmful elements to form high-melting point compounds, which are then removed from the molten steel. It can also improve the deformation ability of hard inclusions, turning hard inclusions into composite inclusions wrapped by sulfides, and reduce the impact of non-deformable inclusions on the processing performance and fatigue performance of steel. At the same time, rare earth elements can improve the segregation of the ingot, improve the uniformity of the organization, and also play a role in refining the grains. Based on this, the Ce element content in the present invention is 0.003-0.007%.

[0021] Furthermore, among the inevitable impurities of the high carbon steel wire rod with high fatigue life described in the present invention, P≤0.015%, S≤0.015%, N≤0.0035%, O≤0.002%, Ti≤0.001%, Al≤0.002%, and Ca≤0.001%.

[0022] In the present invention, Ca, Al, Ti, P, and S are all impurity elements in steel. In order to obtain better performance and higher steel purity, the content of impurity elements in steel should be reduced as much as possible.

[0023] Among them, P and S elements, as impurity elements, will segregate at the austenite grain boundaries to make the steel brittle, and will reduce the wire drawing performance and fatigue life of the wire rod. Therefore, in some embodiments, it is preferred to control the content of P and S elements to P≤0.015% and S≤0.015%.

[0024] In addition, in some embodiments, it is preferred to control N≤0.0035%, O≤0.002%,

[0025] Different from the prior art, the Al, Ti, and Ca elements in the present invention are also controlled as impurity elements. Among them, Al and Ti are easy to generate hard inclusions such as Al2O3 or TiN, thereby reducing the wire drawing performance and fatigue life of the wire rod and the steel wire. Therefore, in order to ensure the performance of the steel, the present invention preferably controls Al≤0.002%, Ti≤0.001%, and Ca≤0.001%.

[0026] Furthermore, in the high-carbon steel wire rod with high fatigue life described in the present invention, the length of inclusions is ≤50 μm.

[0027] In a preferred embodiment of the present invention, through the control of composition and process, the present invention can also modify and optimize inclusions, control hard inclusions such as alumina, reduce the size of inclusions, make the maximum inclusion size ≤50μm, and the number is effectively controlled, which is beneficial to further improve the fatigue performance of steel wire.

[0028] Furthermore, the high carbon steel wire rod with high fatigue life described in the present invention has a tensile strength of ≥1100 MPa and an area reduction ratio of >30%.

[0029] Another object of the present invention is to provide a high-carbon steel wire with a long fatigue life. The high-carbon steel wire has high strength and fatigue performance and can be used to make piano wire and mechanical springs.

[0030] Based on the above objectives, the present invention also provides a high-carbon steel wire with high fatigue life, which is produced by cold drawing the high-carbon steel wire rod as described above.

[0031] Furthermore, the high-carbon steel wire with high fatigue life described in the present invention has a tensile strength of ≥1680MPa and a fatigue life of more than 3 million times.

[0032] Another object of the present invention is to provide a method for manufacturing high carbon steel wire rod, which makes the microstructure and performance of the hot rolled wire rod more uniform by adjusting the high-speed wire controlled rolling and controlled cooling process, reduces the amount of surface decarburization and oxide scale generated, and makes the high carbon steel wire rod have excellent performance and can meet the processing requirements of piano wire and spring steel wire.

[0033] Based on the above invention object, the present invention provides a method for manufacturing a high-carbon steel wire rod with a high fatigue life, which comprises the steps of:

[0034] Smelting and continuous casting;

[0035] Initial rolling and billeting;

[0036] Wire rod controlled rolling: control the heating temperature in the furnace to 1000-1100℃; after the billet is taken out of the furnace, it is rolled by the roughing and medium rolling mill, the starting rolling temperature is controlled to be 980-1050℃, the temperature of the finishing mill is 930-980℃, the temperature of the reducing and sizing mill is 900-950℃, and the wire laying temperature is 890-920℃;

[0037] Stelmore air cooling line controlled cooling: control the cooling rate before pearlite transformation to 10-12℃ / s.

[0038] Furthermore, in the manufacturing method of the high carbon steel wire rod described in the present invention, during the controlled cooling process of the Stelmore air cooling line, the insulation hood is fully opened, and the air volume of the 14 fans of the Stelmore line is adjusted to 70-90% for F1-F6 fans, 50-60% for F7-F10 fans, and 0-30% for F13-F14 fans, so that the cooling rate before the pearlite phase transformation is 10-12°C / s.

[0039] Furthermore, in the method for manufacturing high carbon steel wire rod of the present invention, in the continuous casting step, the superheat is controlled to be 25-38°C, the soft reduction is 20-25mm, and the continuous casting speed is 0.5-0.8m / min.

[0040] Another object of the present invention is to provide a method for manufacturing a high carbon steel wire having high strength and high fatigue performance and meeting the processing requirements of piano wire and spring steel wire.

[0041] Based on the above invention object, the present invention provides a method for manufacturing a high-carbon steel wire with a high fatigue life, which comprises the steps of:

[0042] Smelting and continuous casting;

[0043] Initial rolling and billeting;

[0044] Wire rod controlled rolling: the heating temperature in the furnace is controlled to be 1000-1100℃, and the holding time is 1-2h; after the billet is taken out of the furnace, it is rolled by the roughing and medium rolling mill, and the starting rolling temperature is controlled to be 980-1050℃, the temperature of the finishing mill is 930-980℃, the temperature of the reducing and sizing mill is 900-950℃, and the wire laying temperature is 890-920℃;

[0045] Stelmore air cooling line controlled cooling: control the cooling rate before phase change to 10-12℃ / s to obtain wire rod;

[0046] The wire rod is heat treated in a lead bath and then cold drawn to produce wire.

[0047] Furthermore, in the manufacturing method of the high carbon steel wire described in the present invention, during the controlled cooling process of the Stelmore air-cooling line, the insulation hood is fully opened, and the air volume of the 14 fans of the Stelmore line is adjusted to 70-90% for F1-F6 fans, 50-60% for F7-F10 fans, and 0-30% for F13-F14 fans, so that the cooling rate before the pearlite phase transformation is 10-12°C / s.

[0048] Furthermore, in the method for manufacturing high carbon steel wire rod of the present invention, in the continuous casting step, the superheat is controlled to be 25-38° C., the soft reduction is 20-25 mm, and the continuous casting speed is 0.5-0.8 m / min.

[0049] Furthermore, in the method for manufacturing high carbon steel wire rod of the present invention, in the cold drawing step, the drawing speed does not exceed 4 m / s.

[0050] The high carbon steel hot rolled wire rod and the manufacturing method thereof of the present invention have the following beneficial effects:

[0051] The invention improves the strength and plasticity of the steel material by rationally designing the composition of the high carbon steel wire rod and utilizing precipitation strengthening and fine grain strengthening so that the spacing between the troostite lamellae is between 80 and 200 nm.

[0052] The present invention improves the purity of steel by adding rare earth elements, controls hard inclusions such as alumina, and reduces the size of inclusions. In a preferred embodiment, the maximum inclusion size is controlled to be ≤50μm, and the number is effectively controlled, which is beneficial to the improvement of fatigue performance of steel wire.

[0053] The present invention makes the microstructure and performance of the hot-rolled wire rod more uniform by adjusting the high-speed wire controlled rolling and controlled cooling process, reduces the amount of surface decarburization and scale generation, and makes the high-carbon steel have excellent performance, which can meet the processing requirements of piano wire and spring steel wire.

[0054] In some embodiments of the present invention, the tensile strength of the wire rod is ≥1100 MPa, and the area reduction ratio is >30%, so that the tensile strength of the wire after the cold drawing step is ≥1680 MPa, and the fatigue life is higher than 3 million times. DETAILED DESCRIPTION

[0055] The high carbon steel wire rod, wire material and the manufacturing method thereof described in the present invention will be further explained and illustrated below in conjunction with specific embodiments. However, such explanation and illustration do not constitute an improper limitation on the technical solution of the present invention.

[0056] The high carbon steel wire rods of Examples A1-A6 of the present invention and Comparative Examples B1-B2 are all prepared by the following steps:

[0057] (1) Smelting and continuous casting: Smelting is carried out in an electric furnace or converter, followed by LF refining and VD vacuum degassing to allow the refined slag to fully react with the inclusions in the steel. The vacuum treatment time is at least 30 minutes to ensure that the gas elements in the molten steel are completely removed.

[0058] A continuous casting machine is used to cast molten steel into large square billets with a cross-sectional size of 320mm×425mm. Preferably, the superheat during the continuous casting process is controlled to be 25-38°C, the light reduction is 20-25mm, and the pulling speed is 0.5-0.8m / min. The composition of the resulting billet is listed in Table 1.

[0059] (2) Initial rolling: The continuous casting large square billet is initially rolled after high-temperature diffusion. The heating temperature can be 1020-1060℃ and rolled into a small square billet of 142mm×142mm. The small square billet is tested for surface defects by magnetic particle inspection or ultrasonic inspection, and then finished by grinding wheel and other finishing treatments before entering the heating furnace for high-speed wire finishing rolling.

[0060] (3) High-speed wire rod controlled rolling: The heating temperature in the furnace is controlled to be 1000-1100℃, and the holding time can be 1-2h to ensure uniform heating of the billet. After the billet is taken out of the furnace, it is rolled by the roughing and medium rolling mill. The starting rolling temperature is controlled to be 980-1050℃, the temperature of the finishing mill is 930-980℃, the temperature of the reducing and sizing mill is 900-950℃, the wire laying temperature is 890-920℃, and the specification of the rolled wire rod is Φ5.5-12.5mm.

[0061] (4) After the wire rod is rolled, it enters the Stelmore air cooling line for controlled cooling: the cooling rate before the pearlite phase transformation is controlled to be 10-12°C / s by adjusting the air volume of the fan and the heat preservation cover. In some embodiments, the controlled cooling process is that the heat preservation cover is fully opened, and the air volume of the 14 fans of the Stelmore line is adjusted to 70-90% for the F1-F6 fans, 50-60% for the F7-F10 fans, and 0-30% for the F13-F14 fans, so as to quickly cool the wire rod and refine the structure.

[0062] It should be noted that the chemical element composition and related process design of the high carbon steel wire rods of Examples A1-A6 meet the design specification requirements of the present invention, while the chemical element composition and related process design of the wire rods of Comparative Examples B1-B2 do not meet the design specification requirements of the present invention.

[0063] After obtaining the above-mentioned wire rods, the wire rods of each embodiment and comparative example are subjected to lead bath heat treatment and then cold drawn, the drawing speed does not exceed 4 m / s, and the drawn wire diameter is 1.5-5.0 mm, to obtain the wire rods of embodiments A1-A6 and comparative examples B1-B2.

[0064] Table 1 lists the mass percentages of the chemical elements of the high carbon steel wire rods of Examples A1-A6 and the comparative wire rods of Comparative Examples B1-B2.

[0065] Table 1. (wt%, the balance is Fe and other inevitable impurities except P, S, N, O, Al, Ti, Ca)

[0066]

[0067] Tables 2-1 and 2-2 list the specific process parameters of the high carbon steel wire rods of Examples A1-A6 and the comparative wire rods of Comparative Examples B1-B2 in the manufacturing method and the subsequent cold drawing process parameters of the wire rods.

[0068] Table 2-1.

[0069]

[0070] Table 2-2.

[0071]

[0072] Samples were prepared from the wire rods of each embodiment and comparative example, and the cross-sections of the samples were taken for metallographic examination. The microstructure observation results were listed in Table 3 according to YB / T169-2014 "Metallographic Examination Method for Solenite Content in High Carbon Steel Wire Rods". In addition, inclusions were tested according to GB / T 10561-2005 "Standard Rating Chart Microscopic Examination Method for Determination of Non-Metallic Inclusion Content in Steel", and the test results are listed in Table 3.

[0073] Table 3.

[0074]

[0075]

[0076] It can be seen from Table 3 that, compared with the comparative example, the spacing between the troostite lamellae in each embodiment of the present invention is smaller, and the size of the inclusions is smaller, which is beneficial to the performance improvement.

[0077] The obtained high carbon steel wire rods and corresponding wires of Examples A1-A6 and Comparative Examples B1-B2 were sampled, and the wire rods and wire samples of each embodiment and comparative example were subjected to relevant mechanical property tests. The obtained mechanical property test results are listed in Table 4.

[0078] The relevant mechanical properties test methods are as follows:

[0079] Tensile test: at room temperature, according to GB / T 228.1-2010 "Tensile test of metallic materials - Part 1: Room temperature test method" standard, the tensile strength and area reduction ratio of the high carbon steel hot-rolled wire rod of each embodiment and comparative example are detected.

[0080] Fatigue performance test: A high frequency fatigue testing machine was used to test the fatigue performance of the steel wires of the embodiment and the comparative example.

[0081] Table 4 lists the mechanical property test results of the wire rods and wires of various embodiments and comparative examples.

[0082] Table 4.

[0083]

[0084]

[0085] It can be seen from Table 4 that the tensile strength of the wire rods of each embodiment of the present invention is above 1100MPa, and the area reduction ratio is above 30%. The tensile strength of the wire steel wire corresponding to each wire rod is above 1680MPa, and the fatigue life thereof reaches more than 3 million times, so it can be effectively applied to the products of piano wire and mechanical spring to improve the service life of the products.

[0086] It should be noted that the combination of the various technical features in this case is not limited to the combination described in the claims of this case or the combination described in the specific embodiments. All technical features recorded in this case can be freely combined or combined in any way unless there is a contradiction between them.

[0087] It should also be noted that the above-listed embodiments are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and similar changes or modifications made therewith can be directly derived or easily associated with the contents disclosed by those skilled in the art from the present invention, and all should belong to the protection scope of the present invention.

Claims

1. A high carbon steel wire rod with high fatigue life, containing Fe and unavoidable impurities, characterized in that: It also contains the following chemical elements in the following mass percentages: C: 0.80~0.85%, Si: 0.20~0.30%, Mn: 0.70~0.80%, Ni: 0.01~0.02%, Cr: 0.10~0.20%, Nb: 0.01~0.03%, V: 0.01~0.03%, Ce: 0.003~0.007%; The volume content of troostite in its microstructure is higher than 95%, and the spacing between troostite lamellae is 80-200nm.

2. The high carbon steel wire rod with high fatigue life as claimed in claim 1, characterized in that: The mass percentage of its chemical elements is: C: 0.80~0.85%, Si: 0.20~0.30%, Mn: 0.70~0.80%, Ni: 0.01~0.02%, Cr: 0.10~0.20%, Nb: 0.01~0.03%, V: 0.01~0.03%, Ce: 0.003~0.007%; The balance is Fe and inevitable impurities.

3. The high carbon steel wire rod with high fatigue life as claimed in claim 1 or 2, characterized in that: Among the inevitable impurities, P ≤ 0.015%, S ≤ 0.015%, N ≤ 0.0035%, O ≤ 0.002%, Ti ≤ 0.001%, Al ≤ 0.002%, and Ca ≤ 0.001%.

4. The high carbon steel wire rod with high fatigue life as claimed in claim 1, characterized in that: The inclusion length is ≤50μm.

5. The high carbon steel wire rod with high fatigue life as claimed in claim 1, characterized in that: Its tensile strength is ≥1100MPa and its surface shrinkage is >30%.

6. A high carbon steel wire with high fatigue life, characterized in that: It is made by cold drawing the high carbon steel wire rod as described in any one of claims 1 to 5.

7. The high carbon steel wire rod with high fatigue life according to claim 6, characterized in that: Its tensile strength is ≥1680MPa and its fatigue life is greater than 3 million times.

8. The method for manufacturing a high carbon steel wire rod with a high fatigue life according to any one of claims 1 to 5, characterized in that: It includes the steps of: Smelting and continuous casting; Initial rolling and billeting; Wire rod controlled rolling: the heating temperature in the furnace is controlled to be 1000-1100℃, and the holding time is 1-2h; after the billet is taken out of the furnace, it is rolled by the roughing and medium rolling mill, and the starting rolling temperature is controlled to be 980-1050℃, the temperature of the finishing mill is 930-980℃, the temperature of the reducing and sizing mill is 900-950℃, and the wire laying temperature is 890-920℃; Stelmore air cooling line controlled cooling: control the cooling rate before pearlite transformation to 10-12℃ / s.

9. The method for manufacturing a high carbon steel wire rod with a high fatigue life according to claim 8, characterized in that: In the controlled cooling step, during the controlled cooling process of the Stelmore air cooling line, the thermal insulation hood is fully opened, and the air volume of 14 fans on the Stelmore line is adjusted to 70-100% for F1-F6 fans, 50-60% for F7-F10 fans, and 0-30% for F13-F14 fans, so that the cooling speed is 10-12°C / s before the controlled phase change.

10. The method for manufacturing a high carbon steel wire rod with a high fatigue life according to claim 8, characterized in that: In the continuous casting step, the superheat is controlled at 25-38°C, the soft reduction is 20-25mm, and the continuous casting speed is 0.5-0.8m / min.

11. The method for producing a high carbon steel wire with a high fatigue life according to claim 6 or 7, characterized in that: It includes the steps of: Smelting and continuous casting; Initial rolling and billeting; Wire rod controlled rolling: control the heating temperature in the furnace to 1000-1100℃; after the billet is taken out of the furnace, it is rolled by the roughing and medium rolling mill, the starting rolling temperature is controlled to be 980-1050℃, the temperature of the finishing mill is 930-980℃, the temperature of the reducing and sizing mill is 900-950℃, and the wire laying temperature is 890-920℃; Stelmore air cooling line controlled cooling: control the cooling rate before pearlite transformation to 10-12℃ / s to obtain wire rod; The wire rod is heat treated in a lead bath and then cold drawn to produce wire.

12. The method for manufacturing a high carbon steel wire with a high fatigue life according to claim 11, characterized in that: In the controlled cooling step, during the controlled cooling process of the Stelmore air cooling line, the insulation hood is fully opened, and the air volume of 14 fans on the Stelmore line is adjusted to 70-100% for F1-F6 fans, 50-60% for F7-F10 fans, and 0-30% for F13-F14 fans, so as to control the cooling rate before pearlite phase transformation to 10-12°C / s.

13. The method for manufacturing a high carbon steel wire with a high fatigue life according to claim 11, characterized in that: In the continuous casting step, the superheat is controlled at 25-38°C, the soft reduction is 20-25mm, and the continuous casting speed is 0.5-0.8m / min.

14. The method for manufacturing a high carbon steel wire with a high fatigue life according to claim 11, characterized in that: In the cold drawing step, the drawing speed does not exceed 4 m / s.

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