Apparatus for producing heat-treated steel wire, and method for producing heat-treated steel wire

Abstract

To provide an apparatus for producing a heat-treated steel wire and a method for producing a heat-treated steel wire, capable of producing a heat-treated steel wire having both a non-circular cross section and a circular cross section.SOLUTION: An apparatus 1 for producing a heat-treated steel wire includes: rolling heating means 2 for induction-heating a material steel wire W having a circular cross section Ro with a diameter D to a rolling temperature; rolling processing means 3 for performing rolling processing on the circular cross section Ro of the induction-heated material steel wire W; cooling means 4 for quenching the material steel wire by rapid cooling; and moving means 5 for continuously moving the material steel wire W in the order of the rolling heating means 2, the rolling processing means 3, and the cooling means 4, wherein the rolling processing means 3 is configured such that start and stop of the rolling processing can be switched SW by a switch while the material steel wire is moving.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a manufacturing apparatus for a heat-treated steel wire and a manufacturing method for a heat-treated steel wire. [Background technology]

[0002] For the purpose of providing a method for producing a heat-treated deformed steel wire that is heat-treated in one step by continuously hot-forming a steel wire with a round cross section into a deformed cross section and simultaneously carrying out the forming and quenching heat treatment, a method for producing a heat-treated deformed steel wire has been disclosed (Patent Document 1), in which the steel wire to be processed is rapidly heated to the rolling temperature in a short time by induction heating and / or direct current heating means, hot-rolled into a predetermined deformed cross section, and then rapidly cooled immediately after rolling to perform processing and quenching. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-27138 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the manufacturing method described in Patent Document 1 has limitations in terms of manufacturing heat-treated steel wires having both irregular cross sections, such as angular, rectangular, or approximately trapezoidal cross sections, and round (circular) cross sections, which are used for coil springs and other applications.

[0005] The present invention has been made in view of the above circumstances, and aims to provide a heat-treated steel wire manufacturing apparatus and a heat-treated steel wire manufacturing method that can manufacture heat-treated steel wires having both irregular cross sections and circular cross sections. [Means for solving the problem]

[0006] The heat-treated steel wire manufacturing apparatus according to the present invention comprises a rolling heating means for electrically heating or induction heating a material steel wire having a circular cross section up to a rolling temperature, a rolling processing means for rolling the circular cross section of the material steel wire heated by electrical current or induction, a cooling means for quenching and quenching the material steel wire, and a moving means for continuously moving the material steel wire in the order of the rolling heating means, the rolling processing means and the cooling means, wherein the rolling processing means is capable of switching between starting and ending the rolling processing while the material steel wire is moving.

[0007] The method for producing a heat-treated steel wire according to the present invention comprises a rolling heating step of electrically heating or induction heating a material steel wire having a circular cross section up to a rolling temperature, a rolling processing step of rolling the circular cross section of the material steel wire heated by electrical current or induction heating, and a cooling step of quenching the material steel wire, wherein the material steel wire is continuously moved in the order of the rolling heating step, the rolling processing step, and the cooling step, and the start and end of the rolling processing can be switched while the material steel wire is moving. [Effects of the Invention]

[0008] The present invention provides a heat-treated steel wire manufacturing apparatus and a heat-treated steel wire manufacturing method that can manufacture heat-treated steel wires having both irregular cross sections and circular cross sections. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a conceptual diagram showing a manufacturing apparatus for a heat-treated steel wire according to an embodiment of the present invention. [Figure 2] FIG. 2 is a conceptual diagram showing an example of the cross-sectional shape of a base steel wire before and after rolling by a heat-treated steel wire manufacturing apparatus according to an embodiment of the present invention, where (a) is a conceptual diagram showing an example of the cross-sectional shape of the rolled portion before rolling, and (b) is a conceptual diagram showing an example of the cross-sectional shape of the rolled portion after rolling. [Figure 3]FIG. 3 is a conceptual diagram showing the roll shape of the rolling means in the heat-treated steel wire manufacturing apparatus according to an embodiment of the present invention, the state of the roll, and the ability to switch between these states, where (a) is a conceptual diagram showing the rolling state, and (b) is a conceptual diagram showing the state after the rolling process has been completed. [Figure 4] FIG. 4 is a conceptual diagram showing an example of the shape of a portion of a heat-treated steel wire produced by a production method according to an embodiment of the present invention. [Figure 5] FIG. 5 is a conceptual diagram showing another example of the shape of a portion of a heat-treated steel wire produced by a production method according to an embodiment of the present invention. [Figure 6] FIG. 6 is a conceptual diagram showing another example of the shape of a portion of a heat-treated steel wire produced by the production method according to an embodiment of the present invention. [Figure 7] FIG. 7 is a conceptual diagram showing a manufacturing apparatus for a heat-treated steel wire according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Fig. 1 is a conceptual diagram showing a heat-treated steel wire manufacturing apparatus according to this embodiment. Fig. 2 is a conceptual diagram showing an example of the cross-sectional shape of a base steel wire before and after rolling in the heat-treated steel wire manufacturing apparatus according to this embodiment, where (a) is a conceptual diagram showing an example of the cross-sectional shape of the rolled portion before rolling and (b) is a conceptual diagram showing an example of the cross-sectional shape of the rolled portion after rolling. Fig. 3 is a conceptual diagram showing the roll shape of the rolling means in the heat-treated steel wire manufacturing apparatus according to this embodiment, the state of the roll, and the ability to switch between these states, where (a) is a conceptual diagram showing the state during rolling and (b) is a conceptual diagram showing the state after rolling has been completed.

[0011] As shown in FIGS. 1 to 3 , the heat-treated steel wire manufacturing apparatus 1 according to this embodiment includes a rolling heating means 2 that induction-heats a material steel wire W having a diameter D and a circular cross section Ro to a rolling temperature, a rolling processing means 3 that rolls the circular cross section Ro of the induction-heated material steel wire W, a cooling means 4 that quenches and quenches the material steel wire W, and a moving means 5 that continuously moves the material steel wire W in a moving direction M in the order of the rolling heating means 2, the rolling processing means 3, and the cooling means 4, and the rolling processing means 3 is characterized in that the start and end of the rolling processing can be switched by a switch SW while the material steel wire W is moving.

[0012] As described above, the heat-treated steel wire manufacturing apparatus 1 according to this embodiment can manufacture heat-treated steel wires (specifically, also called quenched steel wires, the same in the present invention) having both a modified cross section De and a circular cross section Ro because the start and end of the rolling process are switchable by the SW. Furthermore, because the start and end of the rolling process are switchable by the SW while the base steel wire W is moving, a decrease in productivity in the manufacture of the heat-treated steel wire can be suppressed.

[0013] Furthermore, by using the switchable SW, the position of the modified cross section De in the heat-treated steel wire to be produced can be freely set. Therefore, the heat-treated steel wire producing apparatus 1 according to this embodiment can also improve versatility when producing heat-treated steel wires having both the modified cross section De and the circular cross section Ro.

[0014] Next, a method for producing a heat-treated steel wire according to this embodiment will be described with reference to FIGS. The method for manufacturing a heat-treated steel wire according to this embodiment includes a rolling heating process (corresponding to rolling heating means 2 in apparatus 1) in which a raw steel wire W having a diameter D and a circular cross section Ro is induction-heated to a rolling temperature, a rolling processing process (corresponding to rolling processing means 3 in apparatus 1) in which the circular cross section Ro of the induction-heated raw steel wire W is rolled, and a cooling process (corresponding to cooling means 4 in apparatus 1) in which the raw steel wire W is quenched and quenched, wherein the raw steel wire W is continuously moved (corresponding to moving means 5 in apparatus 1) through the rolling heating process, the rolling processing process, and the cooling process in that order, and the rolling processing process is characterized in that the start and end of the rolling processing can be switched by SW during the movement M of the raw steel wire W.

[0015] As described above, in the method for producing a heat-treated steel wire according to this embodiment, the start and end of the rolling process are switched by SW, so that a heat-treated steel wire having both a modified cross section De and a circular cross section Ro can be produced. Furthermore, since the start and end of the rolling process are switched by SW while the base steel wire W is moving, a decrease in productivity in the production of the heat-treated steel wire can be suppressed.

[0016] Furthermore, by using the switchable SW, the position of the modified cross section De in the heat-treated steel wire to be produced can be freely set. Therefore, the method for producing a heat-treated steel wire according to this embodiment can improve versatility in producing a heat-treated steel wire having both a modified cross section De and a circular cross section Ro.

[0017] The raw steel wire W having a circular cross section Ro that is induction heated by the rolling heating means 2 (rolling heating process) is In a previous process, for example, a rolled steel material is descaled and then drawn into a base steel wire W having a predetermined diameter D (e.g., 5 mm to 17 mm) and a circular cross section Ro by round drawing. Low-carbon steel (steel material with a carbon concentration of less than 0.30 mass%), medium-carbon steel (steel material with a carbon concentration of 0.30 mass% or more and 0.50 mass% or less), or high-carbon steel (steel material with a carbon concentration of more than 0.50 mass%) is used as the base material for the rolled steel material. When low-carbon steel, medium-carbon steel, or high-carbon steel is used, the alloying elements other than carbon are not particularly limited, but may be, for example, a composition as specified in JIS G 4051, which generally contains 1.5 mass% or less of Si and 1.0 mass% or less of Mn, with the balance being Fe and unavoidable impurities.

[0018] The base steel wire W having a circular cross section Ro produced in the previous step is fed from the unwinder 10 into the rolling heating coil 2a of the rolling heating means 2. The base steel wire W is induction heated by the rolling heating coil 2a to the rolling temperature (temperature range of Ac3 temperature or higher). The temperature range of Ac3 temperature or higher referred to here is preferably 880°C or higher and 1100°C or lower, and more preferably 900°C or higher and 1100°C or lower.

[0019] This heating heats the base steel wire W1 to a temperature range above the Ac3 temperature, resulting in austenitization. This austenitization can cancel out the structure of the base material of the rolled steel material, which has variations in strength.

[0020] Next, the raw steel wire W with a circular cross section Ro that has been induction heated to the rolling temperature is fed between a pair of upper and lower rolls 3a, 3b in the vertical direction and a pair of left and right rolls 3c, 3d in the horizontal direction as shown in Figure 3(b), and the circular cross section Ro of the raw steel wire W is rolled into a modified cross section De by rolling.

[0021] The modified cross section De formed here has an approximately trapezoidal cross section De, as shown in Fig. 2(b). That is, the rolling process for turning the circular cross section Ro into the approximately trapezoidal cross section De is performed by rolling the circular cross section Ro with upper and lower rolls 3a, 3b and left and right rolls 3c, 3d while moving the base steel wire W in the moving direction M, as shown in Fig. 3(a). Then, the side surfaces of the approximately trapezoidal cross section De are formed by the upper and lower rolls 3a, 3b, and the top and bottom surfaces are formed by the left and right rolls 3c, 3d.

[0022] In this embodiment, when a raw steel wire W having a circular cross section Ro with a diameter D of 10.8 mm is used and the circular cross section Ro is rolled, an approximately trapezoidal cross section De is formed, as shown in FIG. 2(b), with a side length A of 14.4 mm, a bottom length B2 of 7.1 mm, a top length B1 of 4.7 mm, a radius of curvature R1 of the curved surface between the top surface and the side surface of 1.4 mm, and a radius of curvature R2 of the curved surface between the side surface and the bottom surface of 1.7 mm. More specifically, this rolling process is carried out by heating the material to a temperature range of Ac3 or higher using the rolling heating means 2 (rolling heating process), and then by using upper and lower rolls 3a, 3b and left and right rolls 3c, 3d in a temperature range of 760°C or higher and 850°C or lower.

[0023] Thereafter, the rolled steel wire W is fed into a water-cooled jacket 4a and quenched by being rapidly cooled in the water-cooled jacket 4a. This quenching is performed by rapidly cooling the steel wire W in the water-cooled jacket 4a from a temperature equal to or higher than the Ar1 temperature (e.g., 740°C) at a cooling rate equal to or higher than the critical cooling rate to a temperature preferably equal to or lower than the Mf point. This allows a quenched martensite structure to be obtained, and the heat-treated steel wire (quenched steel wire) can have high strength. Finally, the produced heat-treated steel wire is wound by a winder 20 and collected.

[0024] The supply to the rolling heating coil 2a, the supply between the rolls, and the supply to the water-cooling jacket 4a are performed by a moving means 5 that continuously moves the raw steel wire W in a moving direction M in the order of the rolling heating means 2 (rolling heating step), the rolling processing means 3 (rolling processing step), and the cooling means 4 (cooling step).

[0025] The moving means 5 continuously moves the material steel wire W through the rolling heating means 2 (rolling heating step), the rolling processing means 3 (rolling processing step), and the cooling means 4 (cooling step) in this order, by utilizing the force of unwinding the material steel wire W from the unwinder 10 and the force of winding the manufactured heat-treated steel wire by the winder 20. Furthermore, auxiliary rollers that assist the movement may be appropriately provided between the unwinder 10, the rolling heating means 2, the rolling processing means 3, the cooling means 4, and the winder 20, respectively.

[0026] Furthermore, the heat-treated steel wire manufacturing apparatus 1 according to this embodiment may be provided with a tensioning means 6 and a tempering heating means 7 between the cooling means 4 and the winder 20, and the moving means 5 may continuously move the base steel wire W in the moving direction M in the order of the rolling heating means 2, the rolling processing means 3, the cooling means 4, the tensioning means 6, and the tempering heating means 7.

[0027] The tension applying means 6 is composed of a pinch roll 6a and a motor 6a equipped with a torque converter reducer, and the pinch roll 6a is driven by the motor 6a. At this time, the pinch rolls 6 rotate at a feed speed slightly faster than the moving speed of the base steel wire W at the rolling exit, so the base steel wire W is quenched while being tensioned by the pinch rolls 6 and fed out. By quenching while applying tension in this manner, a hardened steel wire with high linearity can be obtained. In addition, because the pinch rolls 6 are driven by a motor 6a equipped with a torque converter reducer, excessive tensile force is not applied to the base steel wire W, preventing dimensional fluctuations of the base steel wire W.

[0028] The quenched steel wire is induction heated to a tempering temperature (for example, 400° C. or higher and 700° C. or lower) by the tempering heating coil 7a of the tempering heating means 7, and then is taken up by the winder 20. The heat-treated steel wire wound on the winder 20 is then coiled and formed into a predetermined shape when used for a coil spring.

[0029] In this embodiment, tension is applied to the steel wire by the tension applying means 6, but tension may also be applied by the winding machine 20. In this case, a motor with a torque converter is used to drive the winding machine 20. Heating to the rolling temperature in the rolling heating means 2 (rolling heating step) may be performed by electrical heating, or a combination of induction heating and direct current may be used. In this embodiment, induction heating will be described.

[0030] Next, an example of a specific manufacturing method for manufacturing a heat-treated steel wire having both a modified cross section De and a circular cross section Ro using the heat-treated steel wire manufacturing apparatus 1 according to this embodiment will be described. First, a raw steel wire W having a circular cross section Ro wound around an unwinder 10 is unwound from the unwinder 10 and moved into the rolling heating coil 2a, where it is induction heated to the rolling temperature by the rolling heating coil 2a, and then continuously moved to between the upper and lower rolls 3a, 3b and the left and right rolls 3c, 3d shown in FIG. 3(b).

[0031] At this time, when the tip of the base steel wire W reaches the gap between the rolls, the rolling process has finished (the state shown in FIG. 3(b)), and the tip of the base steel wire W passes through the rolls without contacting them. After that, when the rolling process starts, the base steel wire W continues to move toward the winder 20 (movement direction M), bringing the upper and lower rolls 3a, 3b and the left and right rolls 3c, 3d closer to and into contact with the base steel wire W. Then, while the movement continues, the load L applied to the base steel wire W (circular cross section Ro) by the upper and lower rolls 3a, 3b and the left and right rolls 3c, 3d is gradually increased. By keeping the load L constant at a value that results in an approximately trapezoidal cross section De shown in FIG. 2(b), a steel wire region with a modified cross section De can be formed on the base steel wire W with a circular cross section Ro.

[0032] FIG. 4 is a conceptual diagram showing an example of the shape of a portion of a heat-treated steel wire produced by a production method according to an embodiment of the present invention. As described above, when the raw steel wire W is continuously moved in the direction of the winder 20, the rolling process is started from the state where the rolling process has ended (the state shown in FIG. 3(b)), and the load L is gradually increased up to the load L at which the approximately trapezoidal cross section De shown in FIG. 2(b) is obtained and kept constant, a heat-treated steel wire can be produced having three regions, as shown in FIG. 4, namely, a steel wire region W1 having a circular cross section Ro, a steel wire region W2 having an approximately trapezoidal cross section De, and a change region W3 where the cross section between the steel wire region W1 and the steel wire region W2 changes from the circular cross section Ro to the approximately trapezoidal cross section De.

[0033] To terminate the rolling process, the load L on the material steel wire W applied by the upper and lower rolls 3a, 3b and the left and right rolls 3c, 3d is gradually reduced while the movement continues, until the material steel wire W is finally brought into a state where it is not in contact with the rolls, i.e., the state where the rolling process is completed (the state shown in FIG. 3(b)). After the rolling process is completed, further rolling may be started as described above.

[0034] FIG. 5 is a conceptual diagram showing another example of the shape of a portion of a heat-treated steel wire produced by a production method according to an embodiment of the present invention. As described above, when the raw steel wire W is continuously moved in the direction of the winder 20 while being rolled (the state shown in FIG. 3(a)), the rolling process is terminated, and the raw steel wire W is not rolled from the approximately trapezoidal cross section De shown in FIG. 2(b), i.e., the shape of the raw steel wire W is returned to the circular cross section Ro, a heat-treated steel wire can be produced having three regions, as shown in FIG. 5, namely, a steel wire region W4 consisting of an approximately trapezoidal cross section De, a steel wire region W5 consisting of a circular cross section Ro, and a change region W6 where the cross section between the steel wire region W4 and the steel wire region W5 changes from the approximately trapezoidal cross section De to the circular cross section Ro.

[0035] 6 is a conceptual diagram showing another example of the shape of a portion of a heat-treated steel wire manufactured by a manufacturing method according to an embodiment of the present invention. Note that the cross section of the XX line shown in the steel wire region W9 and the steel wire region W13 has an approximately trapezoidal cross section De, as shown in FIG.

[0036] As described above, while the raw steel wire W continuously moves toward the winder 20, rolling begins on the raw steel wire W with a circular cross section Ro, and the load L is gradually increased and kept constant until the raw steel wire W has an approximately trapezoidal cross section De. Furthermore, while the raw steel wire W is moving, the load L on the raw steel wire W with an approximately trapezoidal cross section De is gradually decreased to terminate the rolling, and finally, the raw steel wire W is brought into a state where it is no longer in contact with the rolls, i.e., where the rolling is completed, and the raw steel wire W is passed through the rolling means 3 while still maintaining its circular cross section Ro. When this process is repeated multiple times, a heat-treated steel wire such as that shown in FIG. 6 is formed.

[0037] That is, as shown in FIG. 6, a heat-treated steel wire can be produced which includes, in this order, a steel wire region W7 having a circular cross section Ro, a change region W8 where the cross section changes from the circular cross section Ro to an approximately trapezoidal cross section De, a steel wire region W9 having an approximately trapezoidal cross section De, a change region W10 where the cross section changes from the approximately trapezoidal cross section De to the circular cross section Ro, a steel wire region W11 having a circular cross section Ro, a change region W12 where the cross section changes from the circular cross section Ro to an approximately trapezoidal cross section De, a steel wire region W13 having an approximately trapezoidal cross section De, a change region W14 where the cross section changes from the approximately trapezoidal cross section De to the circular cross section Ro, and a steel wire region W15 having a circular cross section Ro.

[0038] The steel wire regions that are not subjected to rolling (W1 in FIG. 4, W4 in FIG. 5, W7, W11 and W15 in FIG. 6) are induction heated to the rolling temperature by the rolling heating means 2 (rolling heating process), and then are not rolled by the rolling processing means 3 (rolling processing process), but are rapidly cooled and quenched by the cooling means 4 (cooling process) in the state of a circular cross section Ro.

[0039] That is, in the manufacturing apparatus and manufacturing method for heat-treated steel wire according to an embodiment of the present invention, as shown in Figures 4 to 6, the start and end of the rolling process can be switched SW while the raw steel wire W is moving in the moving direction M, so that the steel wire region having an approximately trapezoidal cross section De can be freely formed at a desired position. Therefore, the heat-treated steel wire manufacturing apparatus and manufacturing method according to this embodiment can also improve versatility when manufacturing heat-treated steel wires having both an approximately trapezoidal cross section De and a circular cross section Ro.

[0040] In addition, among the heat-treated steel wires having both an approximately trapezoidal cross section De and a circular cross section Ro, the steel wire region having an approximately trapezoidal cross section De can absorb greater energy than the steel wire region having a circular cross section Ro, and can withstand a large load in a compact size.

[0041] Therefore, the manufacturing apparatus and manufacturing method for heat-treated steel wire according to this embodiment can create a steel wire region having such an approximately trapezoidal cross section De at any position (because only the necessary portion of the raw steel wire W can be changed to the shape of an approximately trapezoidal cross section De), which is thought to enable a more rational spring design that not only has nonlinear characteristics but also avoids interference with the axis and provides spatial freedom due to its compact size (a high-load spring can be installed in a narrow space), thereby achieving the benefit of weight reduction.

[0042] FIG. 7 is a conceptual diagram showing a manufacturing apparatus for a heat-treated steel wire according to another embodiment of the present invention. The heat-treated steel wire manufacturing apparatus 1A shown in Fig. 7 differs in that it is further provided with a quenching heating means 8. The other configurations are the same as those in Fig. 1 described above, and therefore description thereof will be omitted.

[0043] As shown in FIG. 7, a heat-treated steel wire manufacturing apparatus 1A according to another embodiment of the present invention is characterized in that it further includes quenching heating means 8 that is provided between the rolling means 3 and the cooling means 4 and that induction-heats the rolled raw steel wire W to a quenching temperature. In the rolling means 3, as shown in FIG. 3(a), the upper and lower horizontal rolls 3a, 3b and the left and right vertical rolls 3c, 3d directly contact the raw steel wire W during rolling, so that the raw steel wire W loses heat due to being absorbed by the rolls, and the raw steel wire W may not be sufficiently quenched by the subsequent cooling means 4.

[0044] Therefore, by further providing a quenching heating means 7 that heats the rolled raw steel wire W to a quenching temperature (at least a temperature equal to or higher than the Ar1 temperature (e.g., 740°C), preferably 900°C or higher and 1000°C or lower) after the rolling processing means 3 is completed and before the cooling means 4, the rolled raw steel wire W can be sufficiently quenched.

[0045] Furthermore, as shown in FIG. 7, a method for producing a heat-treated steel wire according to another embodiment of the present invention further includes a quenching heating step, which is provided between the rolling step and the cooling step, and in which the rolled base steel wire is induction-heated to a quenching temperature. In the rolling process, as shown in Figure 3(a), the upper and lower horizontal rolls 3a, 3b and the left and right vertical rolls 3c, 3d are in direct contact with the raw steel wire W during rolling, and therefore the heat of the raw steel wire is absorbed by the rolls and reduced, which may result in insufficient quenching in the subsequent cooling process.

[0046] Therefore, by further providing a quenching heating step after the rolling process and before the cooling process, in which the rolled material steel wire W is heated to a quenching temperature (at least a temperature equal to or higher than the Ar1 temperature (e.g., 740°C), preferably equal to or higher than 900°C and equal to or lower than 1000°C), the rolled material steel wire can be sufficiently quenched. Heating to the rolling temperature in the quenching heating means 8 (quenching heating step) may be performed by electrical heating, or by a combination of induction heating and direct current. The same applies to induction heating by the tempering heating coil 7a of the tempering heating means 7. [Explanation of symbols]

[0047] 1. Heat-treated steel wire manufacturing equipment 2. Rolling heating means 3. Rolling processing method 4 Cooling means 5. Transportation 6. Tensioning means 7 Tempering heating means 10 Unwinder 20 Winder De irregular cross section (approximate trapezoidal cross section) Ro circular cross section SW switchable

Claims

1. a rolling heating means for electrically heating or induction heating a raw steel wire having a circular cross section up to a rolling temperature; a rolling means for rolling the circular cross section of the electrically heated or induction heated base steel wire; a cooling means for quenching the base steel wire; a moving means for continuously moving the base steel wire through the rolling heating means, the rolling processing means, and the cooling means in this order, The rolling processing means is a heat-treated steel wire manufacturing device that can switch between starting and ending the rolling processing while the base steel wire is moving.

2. 2. The heat-treated steel wire manufacturing apparatus according to claim 1, further comprising: a quenching heating means provided between the rolling means and the cooling means, for electrically heating or inductively heating the rolled raw steel wire up to a quenching temperature.

3. a rolling heating step of electrically heating or induction heating a raw steel wire having a circular cross section to a rolling temperature; a rolling process step of rolling the circular cross section of the electrically heated or induction heated base steel wire; a cooling step of quenching the base steel wire, The base steel wire is continuously moved in the rolling heating step, the rolling processing step, and the cooling step in this order, In the rolling process, the start and end of the rolling process can be switched while the base steel wire is moving.

4. 4. The method for producing a heat-treated steel wire according to claim 3, further comprising a quenching heating step, which is provided between the rolling step and the cooling step, and which heats the rolled base steel wire by electrical heating or induction heating up to a quenching temperature.

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