WO2012093715A1

WO2012093715A1 - Steel wire material and method for producing same

Info

Publication number: WO2012093715A1
Application number: PCT/JP2012/050155
Authority: WO
Inventors: 武田　実佳子; 昌平中久保; 和彦桐原; 雅之遠藤
Original assignee: 株式会社神戸製鋼所
Priority date: 2011-01-07
Filing date: 2012-01-06
Publication date: 2012-07-12
Also published as: US20130272914A1; EP2662468A4; KR20140076642A; EP2662468A1; JP2012144756A; JP4980471B1; CN103314125B; KR20130087613A; CN103314125A

Abstract

The steel wire material of the present invention contains 0.05 to 1.2% of C (mass%; same for the chemical components hereafter), 0.01 to 0.5% of Si, 0.1 to 1.5% of Mn, 0.02% or less (but not 0%) of P, 0.02% or less (but not 0%) of S, and 0.005% or less (but not 0%) of N, with the balance being iron and inevitable impurities. The wire material has a scale layer that is no thicker than 7.0 µm or less. The scale layer has an FeO percentage of 30 to 80 vol% and an Fe₂SiO₄ percentage of less than 0.1 vol%. The scale layer that is formed will not peel when cooled after hot rolling or during storage and transport, but will easily peel during mechanical descaling.

Description

Steel wire rod and manufacturing method thereof

TECHNICAL FIELD The present invention relates to a steel wire and a method for producing the same, and in particular, a hot-rolled steel wire formed with a thin scale that can be easily removed by mechanical descaling without being peeled off during cooling after hot rolling or during storage and transportation. (Hereinafter simply referred to as “wire”) and its manufacturing method.

A scale is usually formed on the surface of the wire manufactured by hot rolling, and it is necessary to remove this scale before subjecting the wire to secondary processing such as wire drawing. As a method for removing scale before such secondary processing, a batch-type pickling method has been used in the past, but in recent years, from the viewpoint of pollution problems and cost reduction, a mechanical descaling (hereinafter referred to as MD) method is used. Is being used. Therefore, it is requested | required that the scale with favorable MD property should be formed in the wire.

For example, Patent Documents 1 to 5 can be cited as methods for producing a wire having a scale with good MD properties. In

Patent Documents

1 and 2, the scale amount remaining in the wire after MD is reduced by forming a thick scale with a high FeO ratio. In Patent Literature 3, by reducing the interface roughness, the propagation of cracks generated at the scale interface is promoted, and the residual scale amount is reduced. In Patent Documents 4 and 5, the peelability of the scale is improved by controlling the area ratio of the pores in the scale.

However, Patent Documents 1 to 5 described above have the following problems. In the method of forming the scale thick as in

Patent Documents

1 and 2, the yield is lowered, and the scale is peeled off during the cooling process, storage and transportation, and rust is generated. Further, if the scale is thick, it is difficult to completely remove the scale even if bending strain is applied to the wire by the MD method and further the surface of the wire is brushed. That is, unlike the batch type pickling method, the MD method is difficult to remove the entire scale uniformly and stably, and even if MD is applied to a wire having a thick scale, the surface of the wire In some cases, finely crushed scale powder is scattered. In this way, when the residual scale remaining locally increases, problems such as wrinkles due to poor lubrication and a decrease in the die life may occur in secondary processing such as wire drawing.

In addition, in the method of reducing the interface roughness such as Patent Document 3, it is difficult to stably reduce the interface roughness, and the method of forming voids in the scale as in Patent Documents 4 and 5 is also included. It is difficult to stably form vacancies, and it is difficult for any of these techniques to stably reduce the residual amount of scale.

Furthermore, these Patent Documents 1 to 5 do not consider any scale peeling due to the compressive stress generated during cooling, and the scale peels during cooling, storage, or transportation, and rust is generated on the wire before MD. There was a problem to do.

Japanese Laid-Open Patent Publication No. 4-293721 Japanese Laid-Open Patent Publication No. 11-172332 Japanese Unexamined Patent Publication No. 8-295992 Japanese Unexamined Patent Publication No. 10-324923 Japanese Unexamined Patent Publication No. 2006-28619

The present invention has been made in view of the above circumstances, and the purpose thereof is a wire rod formed with a scale that does not peel off during cooling after hot rolling or during storage / transport, but easily peels off during MD, And a manufacturing method thereof.

The steel wire rod according to the present invention that has achieved the above-mentioned problems is: C: 0.05 to 1.2% (meaning mass%, hereinafter the same for chemical components), Si: 0.01 to 0.5%, Mn: 0.1 to 1.5%, P: 0.02% or less (not including 0%), S: 0.02% or less (not including 0%), N: 0.005% or less (0% Steel wire with the balance being iron and inevitable impurities, the scale having a thickness of 7.0 μm or less, and the FeO ratio in the scale being 30 to 80% by volume, Fe ₂ SiO ₄ ratio is less than 0.1% by volume.

The steel wire rod according to the present invention includes (a) Cr: 0.3% or less (not including 0%) and / or Ni: 0.3% or less (not including 0%), (b) Cu as required. : 0.2% or less (excluding 0%), (c) at least one element selected from the group consisting of Nb, V, Ti, Hf, and Zr is 0.1% or less in total (0 %), (D) Al: 0.1% or less (not including 0%), (e) B: 0.005% or less (not including 0%), (f) Ca: 0.01 % Or less (not including 0%) and / or Mg: 0.01% or less (not including 0%) may be contained.

Further, the present invention provides a mixed gas of oxygen and an inert gas in which the steel having any one of the chemical components described above is rolled up at 750 to 880 ° C. after hot rolling and the oxygen fraction is less than 20% by volume, Or the manufacturing method of the steel wire which cools, spraying an inert gas is also included. The inert gas is preferably nitrogen.

The wire rod of the present invention has a thin (7.0 μm or less) scale in which the FeO ratio is appropriately controlled (30 to 80% by volume) within a predetermined range. Therefore, the scale does not peel off during cooling after hot rolling or during storage / transport, and rusting can be prevented. Furthermore, according to the present invention, since the scale is easily peeled off at the time of MD, sufficient peelability can be ensured with a simple descaling device, and adverse effects during secondary processing such as wire drawing (the surface of the wire surface due to leftover of the scale, It is possible to provide a high quality steel wire rod without causing poor lubrication. Further, since the scale loss is small, the yield can be maintained high.

FIG. 1 is a graph showing the relationship between the FeO ratio in the scale and the residual scale area ratio after MD. FIG. 2 is a graph showing the relationship between the scale thickness and the scale peeling rate of the rolled material.

In the cooling process during the manufacturing process of the wire rod, compressive stress is usually generated in the scale due to the difference in thermal expansion coefficient between the base iron and the scale. As a result, when the wire material was stored and transported after the cooling step, the scale naturally peeled off, which caused rust. In addition, the scale of the wire is removed by MD before secondary processing such as wire drawing. If the scale remains after MD, the die life is reduced. Therefore, there has been a demand for a wire having a scale that does not peel off during the cooling process during the manufacturing process or during storage and transport, but easily peels off during MD.

The MD method is a method in which a wire is distorted to cause cracks in the scale or at the interface between the ground iron and the scale, and the scale is peeled off. Conventionally, in order to improve the peelability of the scale, the ratio of FeO in the scale has been improved. This is because the adhesion strength of FeO to the ground iron is smaller than that of Fe ₂ O ₃ or Fe ₃ O ₄ , so increasing the FeO ratio in the scale is effective in improving the scale peelability during MD. Because it is considered. In order to increase the ratio of FeO in the scale, it is usually necessary to form a scale (secondary scale formed after descaling before finish rolling) at a high temperature. In addition to an increase in thickness and an increase in scale loss, there is a problem that a thick scale peels off during the cooling process, storage and transportation. That is, it was extremely difficult to reduce the thickness of the scale and to secure the FeO ratio in the scale.

Therefore, as a result of the study by the present inventors, the coiling temperature after hot rolling is set to a relatively low temperature, and then cooling while injecting a mixed gas or inert gas of oxygen and inert gas having a low oxygen fraction. As a result, it was found that the scale can be thinned and the FeO ratio in the scale can be secured at a predetermined level or more.

When the thickness of the scale is examined in more detail, it is clear that if the thickness of the scale is 7.0 μm or less, the adhesiveness with the base iron is good and does not peel off during cooling, storage or transportation. became. The scale thickness is preferably 6.5 μm or less, more preferably 6.0 μm or less (particularly 5.5 μm or less). The lower limit of the scale thickness is not particularly limited, but is usually about 0.9 μm.

Furthermore, the present inventors investigated the relationship between the FeO ratio in the scale and the MD property. More specifically, a wire with a length of 200 mm having a composition of 0.9% C-0.25% Si-0.86% Mn-0.007% P-0.0063% S-0.002% N is used. A sample in which the composition of the scale was adjusted by changing the winding temperature condition was prepared. Note that the winding temperature was changed in the range of 700 to 1000 ° C., and N ₂ -10 vol% O ₂ gas was used for cooling after winding. The produced sample was given a deformation strain (6%) corresponding to MD to cause the scale to peel off, and the amount of scale (area ratio) remaining by image processing was measured in the same manner as in Examples described later. FIG. 1 is a graph showing the relationship between the FeO ratio in the scale and the area ratio of the scale remaining after MD.

FIG. 1 shows that if the FeO ratio in the scale is 30 to 80% by volume, the amount of residual scale after MD can be sufficiently reduced. The FeO ratio is preferably 35% by volume or more and 75% by volume or less, more preferably 40% by volume or more and 70% by volume or less, and further preferably 45% by volume or more and 65% by volume or less.

Further, the proportion of Fe ₂ SiO ₄ (firelite) in the scale is less than 0.1% by volume. When Fe ₂ SiO ₄ is generated excessively, it is generated non-uniformly at the interface between the scale and the ground iron, and the scale is exfoliated unevenly during MD, so that the MD property deteriorates. The Fe ₂ SiO ₄ ratio is preferably 0.09% by volume or less, more preferably 0.08% by volume or less, and still more preferably 0.07% by volume or less. On the other hand, Fe ₂ SiO ₄ in the scale is an oxide that is brittle and easily peeled off, and if it is a trace amount, it is uniformly thinly formed, so that it has an effect of improving MD properties. In order to effectively exhibit such an action, it is preferable to ensure 0.01% by volume or more, more preferably 0.02% by volume or more, and further preferably 0.03% by volume or more.

The scale in the present invention includes Fe ₂ O ₃ , Fe ₃ O _{4 and the} like in addition to FeO and Fe ₂ SiO ₄ .

By adjusting the thickness and composition of the scale as described above, the amount of residual scale after MD can be reduced to 30% or less in terms of the area ratio with respect to the amount of scale before MD. This corresponds to approximately 0.05% by mass or less in the remaining scale amount with respect to the mass of the steel wire. The residual scale amount is preferably 25 area% or less, more preferably 20 area% or less.

In order to form the scale described above, a steel having the chemical composition described later is hot-rolled, wound at a relatively low temperature (750 to 880 ° C.), and then mixed with oxygen and an inert gas having a low oxygen fraction. It is important to cool while spraying gas or inert gas. The scale can be thinned by winding at a low temperature. Further, by blowing and cooling a gas having a low oxygen fraction or containing no oxygen as described above, the generated FeO can be secured at a predetermined level or more without changing to Fe ₃ O ₄ .

When the coiling temperature after hot rolling exceeds 880 ° C., the scale thickness exceeds 7.0 μm, the FeO ratio in the scale exceeds 80% by volume, and the MD property deteriorates. In addition, when the coiling temperature exceeds 880 ° C., it may exceed 0.1% by volume, and Fe ₂ SiO ₄ (firelight) is generated unevenly at the interface between the scale and the ground iron. Unevenly peels off and MD properties deteriorate. On the other hand, if the coiling temperature is lower than 750 ° C., the FeO ratio cannot be ensured by 30% by volume or more, and the MD property deteriorates. The winding temperature is preferably 770 ° C. or higher and 875 ° C. or lower, more preferably 790 ° C. or higher and 860 ° C. or lower.

Cooling after hot rolling is performed while spraying a mixed gas of oxygen and an inert gas having an oxygen fraction of less than 20% by volume, or an inert gas. In this way, by blowing and cooling a gas having a low oxygen fraction or containing no oxygen, it is possible to prevent the FeO that has already been produced from becoming Fe ₃ O _4, and to secure the FeO ratio in the scale. Can do. The oxygen fraction is preferably 10% by volume or less, more preferably 5% by volume or less, and still more preferably 0% by volume (that is, only inert gas). Examples of the inert gas include argon, nitrogen and the like, preferably nitrogen. The cooling stop temperature of the cooling performed by spraying the gas is not particularly limited. For example, the cooling may be performed while spraying the gas up to about 550 to 650 ° C., and then cooling to room temperature in the atmosphere.

Hereinafter, the chemical composition of the steel wire rod of the present invention will be described.

C: 0.05 to 1.2%
C is an element that greatly affects the mechanical properties of steel. In order to ensure the strength of the wire, the C content was set to 0.05% or more. The amount of C is preferably 0.15% or more, and more preferably 0.3% or more. On the other hand, when the amount of C becomes excessive, hot workability at the time of manufacturing the wire is deteriorated. Therefore, the C amount is set to 1.2% or less. The amount of C is preferably 1.1% or less, and more preferably 1.0% or less.

Si: 0.01 to 0.5%
Si is an element necessary for deoxidation of steel, and if its content is too small, the production of Fe ₂ SiO ₄ (firelight) becomes insufficient and the MD property deteriorates. Therefore, the Si amount is determined to be 0.01% or more. The amount of Si is preferably 0.1% or more, and more preferably 0.2% or more. On the other hand, when the amount of Si is excessive, problems such as excessive degradation of Fe ₂ SiO ₄ (firelite) cause significant deterioration of MD properties and formation of a surface decarburized layer. Therefore, the Si amount is set to 0.5% or less. The amount of Si is preferably 0.45% or less, and more preferably 0.4% or less.

Mn: 0.1 to 1.5%
Mn is an element useful for securing the hardenability of steel and increasing the strength. In order to effectively exhibit such an action, the amount of Mn was determined to be 0.1% or more. The amount of Mn is preferably 0.2% or more, and more preferably 0.4% or more. On the other hand, when the amount of Mn is excessive, segregation occurs in the cooling process after hot rolling, and a supercooled structure (such as martensite) that is harmful to wire drawing workability is likely to occur. Therefore, the amount of Mn is set to 1.5% or less. The amount of Mn is preferably 1.4% or less, more preferably 1.2% or less.

P: 0.02% or less (excluding 0%)
P is an element that deteriorates the toughness and ductility of steel. In order to prevent disconnection in the wire drawing process or the like, the P content is set to 0.02% or less. The amount of P is preferably 0.01% or less, and more preferably 0.005% or less. The lower limit of the amount of P is not particularly limited, but is usually about 0.001%.

S: 0.02% or less (excluding 0%)
S, like P, is an element that degrades the toughness and ductility of steel. In order to prevent disconnection in the wire drawing or the subsequent twisting process, the S content is set to 0.02% or less. The amount of S is preferably 0.01% or less, and more preferably 0.005% or less. The lower limit of the amount of S is not particularly limited, but is usually about 0.001%.

N: 0.005% or less (excluding 0%)
N is an element that deteriorates the ductility of steel when the content is excessive. Therefore, the N amount is set to 0.005% or less. The amount of N is preferably 0.004% or less, and more preferably 0.003% or less. The lower limit of the N amount is not particularly limited, but is usually about 0.001%.

The basic components of the steel wire rod of the present invention are as described above, and the balance is substantially iron. However, it is naturally allowed that the inevitable impurities brought in depending on the situation of raw materials, materials, manufacturing facilities, etc. are included in the steel wire. Furthermore, it is also recommended to add the following elements as necessary within a range not impeding the effects of the present invention.

Cr: 0.3% or less (not including 0%) and / or Ni: 0.3% or less (not including 0%)
Cr and Ni are both elements that increase the hardenability of steel and contribute to the improvement of strength. In order to effectively exhibit such an action, the Cr content is preferably 0.05% or more, and the Ni content is preferably 0.03% or more. More preferably, the Cr amount and the Ni amount are both 0.10% or more, and more preferably both are 0.12% or more. On the other hand, when the amount of Cr and the amount of Ni are excessive, a martensite structure is likely to be generated, and the adhesion of the scale to the ground iron is excessively increased, so that the peelability of the scale during MD deteriorates. Therefore, it is preferable that the Cr content and the Ni content are both 0.3% or less. More preferably, the Cr content and the Ni content are both 0.25% or less, more preferably 0.20% or less.

Cu: 0.2% or less (excluding 0%)
Cu is an element having an action of promoting scale peeling. In order to effectively exhibit such an action, the amount of Cu is preferably 0.01% or more. The amount of Cu is more preferably 0.05% or more, and further preferably 0.10% or more. On the other hand, when the amount of Cu becomes excessive, peeling of the scale is excessively promoted, the scale is peeled off during rolling, and another thin scale with high adhesion is generated on the peeled surface, and the wire coil is stored and transported. Rust is generated when Therefore, the amount of Cu is preferably 0.2% or less. The amount of Cu is more preferably 0.17% or less, and still more preferably 0.15% or less.

A total of at least one element selected from the group consisting of Nb, V, Ti, Hf, and Zr is 0.1% or less (excluding 0%)
Nb, V, Ti, Hf, and Zr are all elements that form fine carbonitrides and contribute to high strength. In order to effectively exhibit such an action, it is preferable that the Nb amount, the V amount, the Ti amount, the Hf amount, and the Zr amount are all 0.003% or more. The Nb amount, V amount, Ti amount, Hf amount, and Zr amount are all preferably 0.007% or more, and more preferably 0.01% or more. On the other hand, if these elements are excessive, the ductility deteriorates, so the total amount of these elements is preferably 0.1% or less. The total amount of these elements is more preferably 0.08% or less, still more preferably 0.06% or less.

Al: 0.1% or less (excluding 0%)
Al is an element effective as a deoxidizer. In order to effectively exhibit such an action, the Al content is preferably 0.001% or more. The amount of Al is more preferably 0.005% or more, and still more preferably 0.01% or more. On the other hand, when the amount of Al becomes excessive, oxide inclusions such as Al ₂ O ₃ increase, and disconnection frequently occurs during wire drawing. Therefore, the Al content is preferably 0.1% or less. The amount of Al is more preferably 0.08% or less, and still more preferably 0.06% or less.

B: 0.005% or less (excluding 0%)
B is an element that suppresses the formation of ferrite by being present as free B that dissolves in steel (B that does not form a compound), and is particularly effective for high-strength wires that require suppression of longitudinal cracks. It is. In order to effectively exhibit such an action, the B content is preferably 0.0001% or more. The amount of B is more preferably 0.0005% or more, and further preferably 0.0010% or more. On the other hand, when the amount of B becomes excessive, ductility deteriorates. Therefore, the B content is preferably 0.005% or less, more preferably 0.0040% or less, and still more preferably 0.0035% or less.

Ca: 0.01% or less (not including 0%) and / or Mg: 0.01% or less (not including 0%)
Ca and Mg are both elements that have the effect of increasing the ductility by controlling the form of inclusions. Moreover, Ca also has the effect | action which improves the corrosion resistance of steel materials. In order to effectively exhibit such an action, both the Ca content and the Mg content are preferably 0.001% or more. Ca and Mg are both preferably 0.002% or more, and more preferably 0.003% or more. On the other hand, when these elements are excessive, workability deteriorates. Therefore, both the Ca content and the Mg content are preferably 0.01% or less. The Ca content and the Mg content are both preferably 0.008% or less, and more preferably 0.005% or less.

Hereinafter, the present invention will be described more specifically with reference to examples. The present invention is not limited by the following examples, and can of course be implemented with appropriate modifications within a range that can be adapted to the above-described gist. Included in the range.

Steels having chemical compositions shown in Tables 1 and 2 were melted according to a normal melting method, and then billets of 150 mm × 150 mm were produced and heated in a heating furnace. Thereafter, the primary scale generated in the heating furnace is descaled using high-pressure water, and hot rolling is performed under the conditions shown in Table 3 (winding temperature after hot rolling and gas used for cooling). A steel wire rod with a diameter of 5.5 mm was obtained. In addition, all the cooling using the gas shown in Table 3 was performed to about 600 degreeC, and it stood to cool in air | atmosphere after that.

The obtained steel wire was measured by the following method.

(1) Measurement of scale thickness Samples with a length of 10 mm were taken from each of the front end, center portion, and rear end of the coil, and arbitrary three scale sections were taken from each sample with a scanning electron microscope (SEM). Observed (observation magnification: 5000 times). About each measurement location, 10-point scale thickness was measured by the steel wire material circumferential direction length of 100 micrometers, the scale average thickness was calculated | required, and the average value of 3 locations was made into the scale thickness of each sample. Furthermore, the average value of each sample (coil front end, center part, rear end) was calculated, and each test No. And the scale thickness.

(2) Measurement of scale composition
Similarly to the above (1), samples having a length of 10 mm are taken from the front end, the central portion, and the rear end of the coil, and X-ray diffraction is performed on any three scale sections from each sample, and FeO From the peak intensity ratio of Fe ₂ SiO ₄ , Fe ₂ O ₃ , and Fe ₃ O ₄ , the ratio (volume%) of FeO and Fe ₂ SiO ₄ was determined. The average value of three, and the FeO ratio and _Fe 2 SiO ₄ ratio of each sample. Furthermore, the average value of each sample (coil front end, center part, rear end) was calculated, and each test No. FeO ratio and Fe ₂ SiO ₄ ratio.

(3) Measurement of scale peelability of rolled material
A sample having a length of 200 mm was taken from each of the front end, center portion, and rear end of the coil, and the sample was blown to blow off the scale on the surface of the steel wire. The appearance of the wind before and after blowing was photographed with a digital camera, and the area ratio of the peeled scale was determined by comparing the two with image analysis.

(4) MD measurement
Samples with a length of 250 mm were taken from the front end, center, and rear end of the coil, subjected to 6% deformation strain with a tensile tester, taken out from the chuck, and then air blown over the sample to surface the steel wire Blowed off the scale. The external appearance before and after applying the distortion was photographed with a digital camera, and the residual scale area ratio was calculated by comparing the two by image analysis.

The results are shown in Tables 4 and 5 and FIG.

No. in Tables 4 and 5. 1, 2, 4 to 28, 30 to 32, 34, 35, 37 to 39, 41, 42, 44, 45, 48 are examples that satisfy the requirements of the present invention, and the scale thickness and scale composition are appropriate. Therefore, MD property is favorable.

On the other hand, no. 3, 29, 33, 36, 40, 43, 46, 47, and 49 have deteriorated MD properties because the manufacturing conditions do not satisfy the requirements of the present invention.
No. 3, 29, 36, 40, 43, 46, and 47 are examples in which air was blown and cooled after hot rolling, and FeO became Fe ₃ O ₄ during cooling, so that the FeO fraction was It could not be secured, and the MD property deteriorated. No. No. 33 is an example in which the coiling temperature after hot rolling was high. The scale thickness was increased, the FeO ratio was too large, and the Fe ₂ SiO ₄ ratio was also high, so the MD property deteriorated. No. No. 49 is an example in which the coiling temperature after hot rolling was low, the FeO ratio could not be ensured, and the MD property deteriorated. No. Nos. 50 to 54 are examples in which the coiling temperature after hot rolling was higher, the scale thickness exceeded 7.0 μm, the scale peeling rate of the rolled material increased, and rust was generated. That is, no. Nos. 50 to 54 are considered to cause rust due to dropping of the scale during cooling after hot rolling or during storage and transportation.

FIG. 2 shows the relationship between the scale thickness and the scale peeling rate of the rolled material. It can be seen that when the scale thickness exceeds 7.0 μm, the scale peeling rate of the rolled material increases.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention.
This application is based on a Japanese patent application filed on Jan. 7, 2011 (Japanese Patent Application No. 2011-002014), the contents of which are incorporated herein by reference.

Since the steel wire rod of the present invention is excellent in mechanical descaling after hot rolling (before wire drawing), it cuts automobile tire cords (steel cords, bead wires), hose wires, semiconductor silicon, etc. It is useful as a material such as saw wire used in

Claims

C: 0.05 to 1.2% (meaning mass%, hereinafter the same for chemical components),
Si: 0.01 to 0.5%,
Mn: 0.1 to 1.5%
P: 0.02% or less (excluding 0%),
S: 0.02% or less (excluding 0%),
N: a steel wire containing 0.005% or less (excluding 0%), the balance being iron and inevitable impurities,
A steel wire having a scale with a thickness of 7.0 μm or less, an FeO ratio in the scale of 30 to 80% by volume, and an Fe 2 SiO 4 ratio of less than 0.1% by volume .
The steel wire according to claim 1, further comprising at least one of the following (1) to (6).
(1) Cr: 0.3% or less (not including 0%) and / or Ni: 0.3% or less (not including 0%)
(2) Cu: 0.2% or less (excluding 0%)
(3) A total of at least one element selected from the group consisting of Nb, V, Ti, Hf, and Zr is 0.1% or less (excluding 0%)
(4) Al: 0.1% or less (excluding 0%)
(5) B: 0.005% or less (excluding 0%)
(6) Ca: 0.01% or less (not including 0%) and / or Mg: 0.01% or less (not including 0%)
The chemical component steel according to claim 1 or 2,
After hot rolling, it is wound at 750-880 ° C,
A method for producing a steel wire material, characterized by cooling while spraying a mixed gas of oxygen and an inert gas having an oxygen fraction of less than 20% by volume, or an inert gas.
The manufacturing method according to claim 3, wherein the inert gas is nitrogen.