KR102184704B1 - Steel wire having excellent straightness quality and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a steel wire having excellent straightness quality and a manufacturing method thereof. The steel wire having excellent straightness quality comprises a wire which undergoes a heating step of being heated while tension is applied thereto after undergoing a wire drawing step, and undergoes a cooling step. When the straightness of the wire having a length of 400mm is measured after winding the wire on a winding unit having a diameter larger than the diameter of the wire for a prescribed period, the straightness of the wire is 30mm or lower. The manufacturing method of a steel wire having excellent straightness quality comprises a wire preparation step, a heating step, a cooling step, and a straightness measurement step. When the straightness of the wire having a length of 400mm is measured in the straightness measurement step, the straightness of the wire is 30mm or less.

Description

Steel wire having excellent straightness quality and manufacturing method thereof

The present invention relates to a steel wire having excellent straight line quality and a method for manufacturing the same, and more particularly, by heating the steel wire at a temperature above a predetermined temperature for a short period of time, it promotes the deformation aging of the steel wire and improves the straight line quality after aging. It relates to this excellent steel wire and a manufacturing method thereof.

In general, steel wires are used in various industrial fields, and are used in vehicle tires or industrial belts. Steel wires used for various purposes as described above require various quality characteristics, and in particular, when a steel wire is used as a tire reinforcing material, the linearity of the steel wire is required.

The steel wire used in the industrial field is not used immediately after the steel wire is manufactured, but is used several months after the steel wire is wound and stored in a spool having a certain inner diameter. However, in the case of storing and using the steel wire by winding it on a spool as described above, there is a problem that the linearity of the steel wire cannot be maintained.

If the linearity of the steel wire is not maintained, there may be a problem that the steel wire cannot be used in an industrial field requiring linearity. Specifically, in the case of using a steel wire for tire reinforcement, poor linearity affects the work fairness during tire manufacturing, and causes buckling and tip rising phenomena, causing problems during rolling and cutting processes in tire manufacturers. Can occur. In addition, when the linearity of the steel wire is not maintained, a problem occurs in the use of the steel wire in various fields requiring the linearity of the steel wire.

The reasons for the change in the linearity of the steel wire are as follows. Steel wire uses carbon steel as a material, and interstitial solid-solution atoms C and N exist in the carbon steel, and as time passes, they diffuse and move to adjacent potentials and are fixed. Therefore, when a steel wire is manufactured and wound on a spool having a constant inner diameter, the linearity changes due to diffusion and fixation of C and N atoms, and the linearity decreases.

The conventional steel wire has a problem in that it cannot provide a steel wire having excellent linearity due to the above-described problem. In other words, even though the linear characteristics of the conventional steel wire are excellent at the beginning of manufacture, it is difficult to satisfy the linearity quality characteristics because the linear characteristics change due to deformation aging under the stress within the elastic section after a long period of time being wound on a spool having a constant inner diameter. There was this.

The present invention is to solve the above-described problem, and more particularly, by heating the steel wire at a temperature above a certain period for a short time, the steel wire having excellent straight line quality and capable of improving the straight line quality after aging by promoting the deformation aging of the steel wire and It relates to a method of manufacturing the same.

The steel wire having excellent straight line quality of the present invention for solving the above-described problem includes a wire that undergoes a heating step of heating in a state in which tension is applied and undergoes a cooling step after passing through the drawing step, and passing through the cooling step, and attaching the wire to the wire. When the linearity of the wire made of 400mm was measured after winding the winding part with a diameter larger than the diameter of, the linearity of the wire was 30mm or less, and the heating temperature in the heating step was 80 degrees to 220 degrees. And, the heating temperature and heating time of the heating step of the wire satisfy the following formula (A), the heating temperature of the heating step is 80 degrees or more, and the heating time of the heating step is 1 to 2 (s). It is characterized by that. Equation (A): 420 ≥ T + 15.67 ln(t) ≥ 300 (In Equation (A), T is the absolute temperature (K) of the heating temperature, and t is the heating time (s))

Tension applied to the wire in the heating step of the steel wire having excellent linear quality according to the present invention for solving the above-described problem may be 1 to 50% of the cutting strength.

The method for manufacturing a steel wire having excellent straight line quality of the present invention for solving the above-described problem includes: a wire preparation step of preparing a drawn wire; A heating step of heating the wire in a state in which tension is applied; A cooling step of cooling the wire; And a linearity measuring step of measuring the linearity of the wire after winding the wire into a winding portion having a diameter larger than the diameter of the wire for a predetermined period of time; including, and in the linearity measuring step, a straight line of the wire made of 400 mm. When measuring the property, the linearity of the wire is 30 mm or less, the heating temperature in the heating step is 80 degrees to 220 degrees, and the heating temperature and heating time of the heating step of the wire satisfy the following formula (A). , The heating temperature in the heating step is 80 degrees or more, and the heating time in the heating step is 1 to 2 (s). Equation (A): 420 ≥ T + 15.67 ln(t) ≥ 300 (In Equation (A), T is the absolute temperature (K) of the heating temperature, and t is the heating time (s))

In order to solve the above-described problem, a plurality of wires of the method for manufacturing a steel wire having excellent linear quality of the present invention are provided, and a stranded wire step of twisting and twisting the plurality of wires to each other; may further include.

Tension applied to the wire in the heating step of the method for manufacturing a steel wire having excellent straight line quality of the present invention for solving the above-described problem may be 1 to 50% of the cutting strength.

The present invention relates to a steel wire having excellent straight line quality and a method for manufacturing the same, and by heating the steel wire at a constant temperature for a short period of time, there is an advantage of improving the straight line quality after aging by promoting the deformation aging of the steel wire.

In addition, the present invention may not significantly change the microstructure of the steel wire by heating the steel wire at a constant temperature for a short period of time, thereby promoting the deformation aging of the steel wire without deteriorating the physical properties of the steel wire. There is an advantage that can improve quality.

1 is a view showing measuring the linearity of a steel wire having excellent straight line quality according to an embodiment of the present invention.
2 is a view showing productivity according to heating time of a steel wire having excellent straight line quality according to an embodiment of the present invention.
3 is a table showing linearity when a steel wire is manufactured by heating a wire while applying a tension of 1% of the cutting strength and changing the heating time and heating temperature of the wire according to an embodiment of the present invention.
4 is a table showing linearity when a steel wire is manufactured by heating a wire while applying a tension of 5% of the cutting strength and changing the heating time and heating temperature of the wire according to an embodiment of the present invention.
5 is a table showing linearity when a steel wire is manufactured by heating the wire while applying a tension of 15% of the cutting strength and changing the heating time and heating temperature of the wire according to an embodiment of the present invention.
6 is a table showing the linearity when a steel wire is manufactured by heating a wire while applying a tension of 30% of the cutting strength and changing a heating time and a heating temperature of the wire according to an embodiment of the present invention.
7 is a table showing linearity when a steel wire is manufactured by heating a wire while applying a tension of 50% of the cutting strength and changing the heating time and heating temperature of the wire according to an embodiment of the present invention.
8 is a table showing the linearity when a steel wire is manufactured by heating the wire while applying a tension of 1% of the cutting strength and increasing the heating time of the wire according to an embodiment of the present invention.
9 is a table showing a value of a relational expression (A) according to a heating temperature and a heating time according to an embodiment of the present invention and a linear value after 30 days.
10 is a view showing the change in tensile strength of the wire according to the heating temperature.
11 is a diagram showing a process chart of a method for manufacturing a steel wire having excellent straight line quality according to an embodiment of the present invention.

The present invention relates to a steel wire having excellent straight line quality and a method for manufacturing the same, and by heating the steel wire at a temperature above a predetermined temperature for a short time, the steel wire having excellent straight line quality that can improve the straight line quality after aging by promoting the deformation aging of the steel wire and It relates to a method of manufacturing the same. Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

Referring to FIG. 1, a steel wire having excellent straight line quality according to an embodiment of the present invention includes a wire 110 that undergoes a heating step, which is heated while a tension is applied, after a drawing step, and undergoes a cooling step, The wire 110 is characterized in that the linearity is 30mm or less even if it is wound over a certain period of time on the winding portion.

Referring to FIG. 1, linearity according to an embodiment of the present invention may be measured as follows. The wire 110 is wound on a winding portion having a diameter larger than that of the wire for a certain period of time. Thereafter, one end 111 of the wound wire 110 is fixed to one point 120, and the wire 110 is vertically lowered. At this time, the wire 110 is lowered to 400mm. That is, the distance between one end 111 of the wire 110 and the other end 112 of the wire 110 is 400 mm.

The linearity of the wire 110 can be known as a distance between the first axis 121 forming a vertical line from the one point 120 and the other end 112 of the wire 110. Specifically, as the distance between the first shaft 121 and the other end 112 of the wire 110 is smaller, the steel wire has excellent linearity, and the first shaft 121 and the other end of the wire 110 ( The larger the distance between 112) is, the less linear is the steel wire.

As the steel wire according to the embodiment of the present invention is heated at a temperature higher than a certain temperature for a short time to promote deformation aging of the steel wire, when measuring the linearity after winding the wire 110 for a certain period of time in a winding unit, the It is possible to maintain the linearity of the wire 110 to less than 30mm. (Here, the predetermined period in which the wire 110 is wound on the winding portion may be 6 months to 1 year, but is not limited thereto.)

The wire 110 according to an embodiment of the present invention may be made of a carbon steel material, and the wire 110 may be made of a 0.5 to 1.1 wt% carbon steel material.

The wire 110 may be heated in a state in which tension is applied after passing through the drawing step, and the wire 110 passing through the drawing step may undergo a process including a drawing process. Specifically, the wire 110 may be parted in order to secure excellent strength and workability. By performing the parting treatment of the wire 110, a pearlite microstructure, which is an aggregate of ferrite composed of carbon-based cementite and Fe, is obtained.

A plurality of wires 110 that have undergone the new process may be provided, and may be subjected to a stranded wire step in which the plurality of wires 110 are twisted and twisted together. However, the stranded wire step may be omitted if necessary, and when the wire 110 is used as a single steel wire, the stranded wire step may be omitted.

The drawing process is a process involving a large deformation in the material, which deforms the pearlite structure of high carbon steel and promotes the decomposition of cementite in the lamellar layer. When cementite is decomposed by the deformation occurring in the drawing process, the fractions of C and N, which are interstitial solid solution atoms, increase in the ferrite matrix.

Here, the strain aging is caused by interstitial solid solution atoms such as C and N adhere to the potential with the passage of time, and the factors include not only the density of the solid solution atoms, but also the density of time, temperature, and dislocation. Moreover, high-density dislocations exist inside the material with large plastic deformation through the wire drawing process, further promoting the aging phenomenon.

In other words, when a steel wire that has been drawn is wound on a spool having a certain inner diameter, cementite is decomposed over time, resulting in deformation aging, followed by a change in linearity, and thus the target linearity cannot be obtained.

In order to prevent this, the wire 110 according to an embodiment of the present invention is artificially accelerated and completed the diffusion of solid solution by going through a heating step in which tension is applied and then a cooling step. . In this way, as the diffusion of solid-solution atoms is artificially promoted and completed, the aging phenomenon does not occur in the wire 110 even after the wire 110 is wound on the winding portion having a predetermined inner diameter.

As described above, the steel wire according to the embodiment of the present invention can improve the linearity by promoting the deformation aging of the wire 110, but does not affect other physical properties of the wire 110 when promoting deformation aging. It is desirable not to.

To this end, the heating time in the heating step of the wire 110 according to an embodiment of the present invention is preferably 0.02 to 10 (s), more preferably 0.02 to 5 (s).

If the wire 110 is heated for an excessively long time in the heating step of the wire 110, the deformation aging of the wire 110 may be promoted, but there is a risk that the productivity of manufacturing the steel wire is lowered.

Referring to FIG. 2, it can be seen that the productivity of the steel wire decreases as the heating time increases in the heating step of the wire 110, and the productivity decreases sharply at 10 (s) or more. That is, if the heating time is lengthened in the heating step of the wire 110, the productivity decreases as the production speed is slowed, and accordingly, the problem of increasing the manufacturing cost may occur.

In addition, if the wire 110 is not heated for a sufficient time in the heating step of the wire 110, deformation aging is not promoted. Specifically, when the heating time in the heating step of the wire 110 is 0.01 (s) less than 0.02 (s), the carbon atoms decomposed in the cementite at the cementite and ferrite interface are ferrite regions as the heating time is too short. There is not enough driving force to cause the movement to occur, and thus the acceleration of carbon fixation to the electric potential does not occur. Therefore, the heating time in the heating step of the wire 110 is preferably 0.02 to 10 (s), more preferably 0.02 to 5 (s).

At the same time, the heating temperature and the heating time in the heating step of the wire 110 according to an embodiment of the present invention satisfy the following formula (A), but the heating temperature in the heating step of the wire 110 is 80 degrees or more. It is desirable. Equation (A): T + 15.67 ln(t) ≥ 300 (In Equation (A), T is the absolute temperature (K) of the heating temperature, and t is the heating time (s))

3 to 7, when the heating temperature and the heating time of the heating step of the wire 110 do not satisfy Equation (A), the deformation aging of the wire 110 is not sufficiently accelerated. It can be seen that the linearity of the wire 110 is not improved.

(FIG. 3 shows heating while applying 1% of the cutting strength to the wire 110, and FIG. 4 shows heating while applying 5% of the cutting strength to the wire 110. , Figure 5 shows the heating while applying a tension of 15% of the cutting strength to the wire 110, Figure 6 shows the heating while applying a tension of 30% of the cutting strength to the wire 110 , Figure 7 shows the heating while applying a tension of 50% of the cutting strength to the wire 110. In Figures 3 to 7, the numerical values of the wire 110 through the above-described linearity measurement method It is a measure of linearity.)

At this time, the heating temperature of the wire 110 should be 80 degrees or more. If the heating temperature of the wire 110 is less than 80 degrees, even if the heating temperature and the heating time of the heating step of the wire 110 satisfy the formula (A), the deformation aging of the wire 110 is not accelerated. Able to know.

Specifically, 60 degrees-1 second, 40 degrees-1 second in FIG. 3, 60 degrees-1 second, 40 degrees-1 second in FIG. 4, 60 degrees-1 second, 40 degrees-1 second, and 6 in FIG. The embodiment of 60 degrees -1 second, 40 degrees -1 second, and 60 degrees -1 second and 40 degrees -1 second of FIG. 7 satisfies Equation (A), but as the heating temperature is less than 80 degrees, the deformation aging is It can be seen that the linearity is not good because it is not promoted.

FIG. 8 shows the heating time of the wire 110 being less than 80 degrees and a longer heating time (more than 10 seconds). Referring to FIG. 8, it can be seen that the deformation aging of the wire 110 is not accelerated even if the time is increased below 80 degrees. As described above, when the heating temperature of the wire 110 is less than 80 degrees, deformation aging is not promoted even if the heating time of the wire 110 is lengthened.

Strain aging occurs when interstitial solid solution atoms such as C and N adhere to an electric potential with the passage of time, and the factors include not only the density of the solid solution atom, but also the density of time, temperature, and dislocation. That is, a certain temperature is required to fix the interstitial solid solution atoms such as C and N to the potential with the passage of time. When the heating temperature of the wire 110 is less than 80 degrees, the interstitial solid solution atoms such as C or N Deformation aging is not promoted as it does not stick to dislocations over time.

Therefore, even if the heating temperature and the heating time of the wire 110 in the heating step satisfy Equation (A), if the heating temperature in the heating step is less than 80 degrees, deformation aging is not promoted.

Further, even if the heating temperature of the heating step of the wire 110 is greater than 80 degrees, if the heating temperature and the heating time of the heating step of the wire 110 do not satisfy the formula (A), the deformation aging is It is not promoted. Specifically, referring to 80 degrees-0.01 seconds, 0.02 seconds, and 0.03 seconds in FIG. 9, the heating temperature in the heating step is 80 degrees or more, but since the equation (A) is not satisfied, the deformation aging is not accelerated, and thus linearity It can be seen that this has not been improved.

In addition, even if the heating temperature of the wire 110 in the heating step is 80 degrees or more, the deformation aging is not promoted when the heating time of the wire 110 in the heating step is less than 0.02 seconds. Specifically, referring to 100 degrees-0.01 seconds, 150 degrees-0.01 seconds, and 200 degrees-0.01 seconds of FIG. 9, the heating temperature in the heating step is 80 degrees or more, and the equation (A) is satisfied, but the heating time is sufficient. It can be seen that it does not promote deformation aging.

This is because the heating time of the heating step of the wire 110 is considerably small. Even if the heating temperature of the heating step of the wire 110 is 80 degrees or more, if the heating time of the heating step of the wire 110 is considerably small, the interstitial solid solution atoms such as C and N are displaced with the passage of time. As it is not adhered to, deformation aging is not promoted.

Therefore, the heating temperature and heating time of the wire 110 in the heating step satisfy the following formula (A), but the heating temperature in the heating step of the wire 110 is preferably 80 degrees or more. That is, even if the heating temperature is 80°C or higher, if the heating time is too small, the deformation aging is not accelerated. Therefore, the heating time of the heating step of the wire 110 is preferably 0.02 seconds or more.

According to an embodiment of the present invention, the tension applied to the wire 110 in the heating step of the wire 110 is preferably 1 to 50% of the cutting strength. The tension applied to the wire 110 in the heating step of the wire 110 affects the heating temperature and heating time.

As described above, the heating step serves to promote deformation aging through diffusion of interstitial solid-solution atoms, and when the tension applied to the wire 110 increases, the straightness of the wire 110 increases, and the same Higher linearity improvement effect appears under heating conditions. Therefore, it is preferable that the tension applied to the wire 110 in the heating step of the wire 110 is greater than 1% of the cutting strength.

However, if the tension applied to the wire 110 in the heating step of the wire 110 is too large, there is a risk that the physical properties of the wire 110 are deteriorated by the tension. Therefore, it is preferable that it is less than 50% of the cutting force applied to the wire 110 in the heating step of the wire 110. (Here, the cutting strength is one of the physical properties of the wire, and it indicates the strength at the time when the wire breaks when tension is applied in the axial direction at both ends of the wire.)

However, the tension applied to the wire 110 is not limited to 1 to 50% of the cutting strength, and of course, an appropriate tension may be applied if necessary.

The heating temperature in the heating step of the wire 110 according to an embodiment of the present invention is preferably 80 to 220 degrees. The point that the heating temperature should be 80 degrees or more is omitted as described above. Referring to FIG. 10, if the heating temperature is 220 degrees or less in the heating step of the wire 110, the tensile strength can be increased without significantly changing the microstructure.

However, it can be seen that when the heating temperature is excessively higher than 220 degrees, the physical properties of the wire become disadvantageous to the extent that microstructure change is observed, and the tensile strength gradually decreases. That is, if the heating temperature is greater than 220 degrees, the strain aging can be promoted, but there is a risk that the tensile strength of the wire is lowered. Therefore, the heating temperature of the wire 110 in the heating step is preferably 80 to 220 degrees.

The steel wire having excellent straight line quality according to the embodiment of the present invention described above may be manufactured by the following method. In the method of manufacturing a steel wire having excellent straight line quality according to an embodiment of the present invention, which will be described later, all the features of the steel wire having excellent straight line quality can be applied.

Referring to FIG. 11, a wire preparation step (S110), a heating step (S130), a cooling step (S140), and a linearity measurement step (S150) according to an embodiment of the present invention are included.

The wire preparation step (S110) is a step of preparing a drawn wire. It goes without saying that the wire preparation step (S110) may include various processes if the step of drawing the wire 110 is included.

The method of manufacturing a steel wire having excellent straight line quality according to an embodiment of the present invention may further include a stranded wire step (S120). The twisting step (S120) is a step of having a plurality of wires 110 and twisting the plurality of wires 110 to each other. The stranded wire step (S120) may be included when manufacturing a steel wire including a stranded wire, and the stranded wire step (S120) may be omitted when manufacturing a single steel wire.

The heating step (S130) is a step of heating the drawn wire 110 in a state in which tension is applied. The heating temperature in the heating step (S130) may be 80 to 220 degrees.

In addition, the heating temperature and heating time of the heating step (S130) are equation (A): T + 15.67 ln(t) ≥ 300 (where T is the absolute temperature (K) of the heating temperature, and t is The heating time (s)) is satisfied, but the heating temperature in the heating step (S130) may be 80 degrees or more.

In addition, the heating time of the heating step (S130) may be 0.02 to 10 (s), and the tension applied to the wire 110 in the heating step (S130) may be 1 to 50% of the cutting strength. However, the tension applied to the wire 110 is not limited to 1 to 50% of the cutting strength, and of course, an appropriate tension may be applied if necessary.

The critical significance of the values of the heating temperature, heating time, and tension in the heating step (S130) has been described above in the steel wire having excellent straight line quality according to an embodiment of the present invention, and a detailed description thereof will be omitted.

The cooling step (S140) is a step of cooling the wire 110 that has been subjected to the heating step (S130). Since the wire 110 that has gone through the heating step (S130) is exposed to an environment in which C and N in the wire 110 are easily diffused, the deformation aging cannot be completely suppressed when cooling is insufficient and winding is performed. . Therefore, it is necessary to cool the wire 110 that has passed through the heating step S130 in the cooling step S140.

The cooling temperature of the cooling step (S140) is preferably 50 degrees or less, and since the cooling temperature of the cooling step (S140) may increase as the cooling temperature decreases, cooling may be performed at 50 degrees or less. Specifically, the cooling step (S140) is most preferably performed at room temperature. However, the cooling temperature in the cooling step (S140) is not limited thereto, and may be changed as necessary. The cooling step (S140) may be performed in various ways, and methods such as air cooling, gas cooling such as reducibility and inertness, and water cooling may be used.

The linearity measurement step (S150) is a step of measuring the linearity of the wire 110 after winding the wire 110 to a winding portion having a diameter larger than the diameter of the wire for a certain period of time.

Referring to FIG. 1, in the linearity measurement step S150, linearity may be measured as follows. The wire 110 is wound on a winding portion having a diameter larger than that of the wire for a certain period of time. Thereafter, one end 111 of the wound wire 110 is fixed to one point 120, and the wire 110 is vertically lowered. At this time, the wire 110 is lowered to 400mm. That is, the distance between one end 111 of the wire 110 and the other end 112 of the wire 110 is 400 mm.

The linearity of the wire 110 measured in the linearity measurement step (S150) is, the first axis 121 forming a vertical line from the one point 120 and the other end 112 of the wire 110 It can be the gap you make. Specifically, as the distance between the first shaft 121 and the other end 112 of the wire 110 is smaller, the steel wire has excellent linearity, and the first shaft 121 and the other end of the wire 110 ( The larger the distance between 112) is, the less linear is the steel wire.

In the method of manufacturing a steel wire having excellent straight line quality according to an embodiment of the present invention, after winding the wire 110 to a winding portion for a certain period of time as in the above-described method, the wire made of 400 mm in the linearity measurement step (S150) When measuring the linearity of, it is possible to manufacture a steel wire having a linearity of 30 mm or less of the wire 110.

The above-described steel wire having excellent linear quality and a method of manufacturing the same according to the present invention have the following effects.

The steel wire having excellent straight line quality and its manufacturing method according to an embodiment of the present invention have the advantage of improving the straight line quality after aging by promoting the deformation aging of the steel wire by heating the steel wire at a constant temperature for a short time.

In addition, the steel wire having excellent straight line quality according to an embodiment of the present invention and the manufacturing method thereof may not significantly change the microstructure of the steel wire as the steel wire is heated at a constant temperature for a short period of time, thereby improving the physical properties of the steel wire. It has the advantage of improving the quality of the straight line after aging by promoting the deformation aging of the steel wire without deteriorating it.

Specifically, the steel wire having excellent straight line quality and its manufacturing method according to an embodiment of the present invention do not change the physical properties of the wire by heating the wire for a short time (0.02 to 10 (s) or 0.02 to 5 (s)). There is an advantage of improving the linearity of the wire.

Here, in order to accelerate the strain aging of the wire while heating the wire for a short period of time, the heating temperature and heating time in the heating step of the wire are Equation (A): T + 15.67 ln(t) ≥ 300 (T in Equation (A)) Is the absolute temperature (K) of the heating temperature, and t is the heating time (s), but the temperature in the heating step must be 80 degrees or more.

3 to 9, if the above conditions are not satisfied, the deformation aging is not sufficiently promoted. The steel wire having excellent straight line quality according to an embodiment of the present invention satisfies the above conditions and heats the wire. There is an advantage of improving the linearity of the wire without changing the physical properties of the wire.

In the steel wire having excellent straight line quality and the manufacturing method thereof according to another embodiment of the present invention, Equation (A): T + 15.67 ln(t) ≥ 300 (In Equation (A), T is the absolute temperature (K) of the heating temperature, , t is the heating time (s)) may be modified as follows. Equation (A) may be modified to 420 ≥ T + 15.67 ln(t) ≥ 300, and Equation (A) may have an upper limit of 420.

Increasing the values of the heating temperature and heating time while increasing the value of Equation (A) can promote deformation aging, but if the upper limit of Equation (A) exceeds 420, it may become inefficient in terms of economy and workability. . In addition, as the values of the heating temperature and heating time are increased to exceed 420, which is the upper limit of the equation (A), the risk of affecting the physical properties of the wire increases. Therefore, the equation (A) is 420 ≥ T + 15.67 ln(t) ) ≥ 300 may be made.

In the above, the present invention has been described in detail with reference to a preferred embodiment, but the present invention is not limited to the above embodiment, and various modifications may be provided within the scope not departing from the scope of the present invention. Therefore, the true technical protection scope of the present invention should be determined by the technical spirit of the appended claims.

110...wire
111... wire first
112...the other end of the wire
120... one point
121...dismiss
S110...wire preparation steps
S120...stranded wire step
S130...heating step
S140...cooling stage
S150... linearity measurement step

Claims (5)

In a steel wire requiring linearity,
After passing through the drawing step, the wire undergoes a heating step heated in a state in which tension is applied, and undergoes a cooling step; includes,
When the wire was wound on a winding portion having a diameter larger than the diameter of the wire for a certain period of time, the linearity of the wire made of 400 mm was measured,
The linearity of the wire is less than 30mm,
The heating temperature in the heating step is 80 degrees to 220 degrees,
The heating temperature and heating time of the heating step of the wire satisfy the following formula (A),
The heating temperature in the heating step is 80 degrees or more,
The heating time of the heating step is a steel wire having excellent straight line quality, characterized in that 1 to 2 (s).
Equation (A): 420 ≥ T + 15.67 ln(t) ≥ 300 (In Equation (A), T is the absolute temperature (K) of the heating temperature, and t is the heating time (s)) The method of claim 1,
Steel wire having excellent straight line quality, characterized in that the tension applied to the wire in the heating step is 1 to 50% of the cutting strength. In the steel wire manufacturing method requiring linearity,
A wire preparation step of preparing a drawn wire;
A heating step of heating the wire in a state in which tension is applied;
A cooling step of cooling the wire; And
Including; a linearity measuring step of measuring the linearity of the wire after winding the wire to a winding portion having a diameter larger than the diameter of the wire for a certain period of time, and
When measuring the linearity of the wire made of 400 mm in the linearity measurement step, the linearity of the wire is 30 mm or less,
The heating temperature in the heating step is 80 degrees to 220 degrees,
The heating temperature and heating time of the heating step of the wire satisfy the following formula (A),
The heating temperature in the heating step is 80 degrees or more,
The heating time of the heating step is 1 to 2 (s), characterized in that the steel wire manufacturing method excellent in straight line quality.
Equation (A): 420 ≥ T + 15.67 ln(t) ≥ 300 (In Equation (A), T is the absolute temperature (K) of the heating temperature, and t is the heating time (s)) The method of claim 3,
The wire is provided with a plurality,
A method of manufacturing a steel wire having excellent straight line quality, further comprising: a stranded wire step in which a plurality of the wires are twisted and twisted to each other. The method of claim 3,
The method of manufacturing a steel wire having excellent straight line quality, characterized in that the tension applied to the wire in the heating step is 1 to 50% of the cutting strength.

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