KR20140076642A - Method for producing steel wire material - Google Patents

Abstract

The steel wire rod according to the present invention is characterized in that the steel wire rod has a composition of C: 0.05 to 1.2% (in mass%, the same applies to chemical components), Si: 0.01 to 0.5%, Mn: 0.1 to 1.5% %), S: not more than 0.02% (not including 0%), N: not more than 0.005% (not including 0%) and the balance being iron and inevitable impurities, And a Fe ₂ SiO ₄ ratio of less than 0.1% by volume, and is not peeled off during cooling after hot rolling, during storage and transportation, and has an MD A scale which is easily peeled off is formed.

Description

METHOD FOR PRODUCING STEEL WIRE MATERIAL [0001]

The present invention relates to a steel wire rod and a method of manufacturing the same, and particularly relates to a steel wire rod and a method for manufacturing the same, Simply referred to as " wire rod "), and a manufacturing method thereof.

Scales are usually formed on the surface of the wire rod produced by hot rolling and it is necessary to remove the scale before the wire rod is subjected to secondary working such as drawing. Conventionally, a batch-type pickling method has been used as a scale removing method before the secondary processing. Recently, mechanical descaling (hereinafter referred to as MD) method is used from the viewpoint of pollution problem and cost reduction. Therefore, it is required that a wire having good MD property is formed on the wire.

As a method for producing a wire having a scale with good MD characteristics, for example, Patent Documents 1 to 5 can be mentioned. In Patent Documents 1 and 2, the amount of scale remaining in the wire after MD is reduced by forming a high scale FeO ratio and a large scale. In Patent Document 3, by reducing the interfacial roughness, the entirety of the cracks generated at the scale interface is promoted to reduce the residual scale amount. In Patent Documents 4 and 5, the peelability of the scale is improved by controlling the area ratio of the holes in the scale.

However, the above-described Patent Documents 1 to 5 have the following problems. In the method of forming a large scale 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. In addition, if the scale is thick, it is difficult to remove the scale completely even if bending modification is applied to the wire by the MD method and brushing of the wire surface is performed. In other words, unlike the batch-type pickling method, the MD method is difficult to uniformly and stably remove the entire scale, and even if MD is applied to a wire material having a thick scale, a fine- It may be dotted. If the residual scale remaining locally increases, problems such as scratches due to defective lubrication or deterioration of die life are caused in secondary processing such as drawing.

As a method for reducing the interfacial roughness of Patent Document 3 and the like, it is difficult to stably reduce the interfacial roughness, and it is difficult to stably form a void even in the method of forming the void in the scale as in Patent Documents 4 and 5 All of these techniques are difficult to stably reduce the scale remaining amount.

In these Patent Documents 1 to 5, scale peeling due to the compressive stress generated during cooling is not taken into consideration at all, and scale is peeled off during cooling, storage and transportation, thereby causing rust in the wire rod before MD.

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

The present invention has been made in view of the above circumstances, and an object thereof is to provide a wire having a scale which is not peeled during cooling after hot rolling, during storage and transportation, and easily peeled off at the time of MD, and a manufacturing method thereof .

The steel wire rod according to the present invention which achieves the above object is characterized by containing 0.05 to 1.2% of C, 0.1 to 1.5% of Si, 0.1 to 1.5% of Si, 0.02% or less (not including 0%), S: not more than 0.02% (excluding 0%), N: 0.005% or less (not including 0%) and the balance being iron and inevitable impurities The steel wire rod has a scale of 7.0 탆 or less in thickness, FeO ratio in the scale is 30 to 80% by volume, and Fe ₂ SiO ₄ ratio is less than 0.1% by volume.

(A) 0.3% or less of Cr (not including 0%) and / or Ni of 0.3% or less (excluding 0%), (b) 0.2% or less of Cu (Excluding 0%), (c) at least one element selected from the group consisting of Nb, V, Ti, Hf and Zr in a total amount of not more than 0.1% d) Al: not more than 0.1% (not including 0%), (e) B: not more than 0.005% (not including 0%), (f) Ca: not more than 0.01% And / or Mg: not more than 0.01% (not including 0%).

Further, the present invention is characterized in that the steel of any one of the chemical components described above is hot-rolled and then rolled at 750 to 880 DEG C, and a mixed gas of oxygen and an inert gas having an oxygen fraction of less than 20% And a method of manufacturing a steel wire rod. The inert gas is preferably nitrogen.

The wire of the present invention has a FeO ratio appropriately controlled (30 to 80% by volume) in a predetermined range, and has a thin (7.0 탆 or less) scale. Therefore, the scales do not peel off during cooling after the hot rolling, storage and transportation, and the occurrence of rust can be prevented. Further, according to the present invention, since the scale is easily peeled off during MD, a satisfactory peeling property can be secured by a simple descaling device, and adverse effects (secondary scratches on the surface of the wire due to residual scale, Lubrication failure, etc.), and a steel wire rod of high quality can be provided. In addition, since the scale loss is small, the yield can be kept high.

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

In the cooling step during the manufacturing process of the wire rod, a compressive stress is generally generated in the scale due to the difference in coefficient of thermal expansion between the steel strip and the scale. As a result, when the wire rod is stored and transported in the cooling step or thereafter, the scale is naturally peeled off, which causes rust. In addition, the wire rod is scaled down by MD before secondary processing such as drawing, and if the scale remains after MD, the dice life is lowered. Therefore, there has been a demand for a wire material having a scale that is not peeled off during the cooling process during the manufacturing process, storage and transportation, and easily peeled off at the time of MD.

The MD method is a method in which deformation is imparted to a wire to generate a crack in the scale or at the interface between the steel and the scale, thereby peeling the scale. Conventionally, in order to improve the peelability of the scale, the FeO ratio in the scale is improved. This is because it is believed that increasing the FeO ratio in the scale is effective for improving the scale peelability at the time of MD because the adhesion strength of FeO with the iron base is smaller than that of Fe ₂ O ₃ or Fe ₃ O ₄ . In order to increase the FeO ratio in the scale, it is usually necessary to form a scale (a secondary scale formed after descaling before finishing rolling) at a high temperature. However, if a scale is formed at a high temperature, And the thick scale is peeled off during the cooling process, storage and transportation. That is, it is extremely difficult to make the thickness of the scale thin and secure the FeO ratio in the scale.

Therefore, as a result of the investigation by the present inventors, it has been found that if the coiling temperature after hot rolling is set to a relatively low temperature and thereafter the mixed gas of inert gas and inert gas having a low oxygen fraction or inert gas is cooled while being sprayed, Further, it has been found that the FeO ratio in the scale can be secured to a predetermined value or more.

When the thickness of the scale is examined in more detail, it has become clear that the scale has a good adhesion with the base metal when the thickness is 7.0 탆 or less, and is not peeled off during cooling, storage and transportation. 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 mu m.

Further, the present inventors investigated the relationship between the FeO ratio and the MD property in the scale. More specifically, a wire having a composition of 0.9% C-0.25% Si-0.86% Mn-0.007% P-0.0063% S-0.002% N and having a length of 200 mm was used to change the coiling temperature The adjusted sample was prepared. The coiling temperature was varied in the range of 700 to 1000 캜, and N ₂ -10% by volume O ₂ gas was used for cooling after coiling. Deformation distortion (6%) corresponding to the MD was given to the produced sample and the scale was peeled off. The scale amount (area ratio) remained by image processing was measured in the same manner as in the later example. 1 is a graph showing the relationship between the FeO ratio in the scale and the area ratio of the scale remaining after MD.

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

In addition, the Fe ₂ SiO ₄ (Fealite) ratio in the scale is set to be less than 0.1% by volume. If excess Fe ₂ SiO ₄ is produced, the scale is irregularly generated at the interface between the scale and the iron, and the scale is unevenly peeled off at the time of MD, so that the MD property is deteriorated. 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 which is easy to peel off, and if it is a very small amount, Fe ₂ SiO ₄ is produced uniformly thinly, and therefore has an effect of improving the MD property. In order to effectively exhibit such an action, it is preferable to secure at least 0.01% by volume, more preferably at least 0.02% by volume, and still more preferably at least 0.03% by volume.

The scale of 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 residual scale after MD can be made 30% or less in terms of area ratio with respect to the scale before MD. This corresponds to about 0.05 mass% or less in terms of the residual scale amount with respect to the mass of the steel wire rods. The residual scale amount is preferably 25% by area or less, more preferably 20% by area or less.

In order to form the above-described scale, a steel having a chemical composition of a later stage is hot-rolled and then rolled at a relatively low temperature (750 to 880 DEG C), and then a mixed gas or inert gas of oxygen and an inert gas, It is important to cool it. The scale can be thinned by winding at a low temperature. In addition, it is possible to secure a predetermined amount or more of the generated FeO without changing the FeO into Fe ₃ O ₄ by jetting and cooling the gas having a low oxygen content or containing no oxygen as described above.

When the coiling temperature after hot rolling exceeds 880 캜, the MD thickness is deteriorated when the scale thickness exceeds 7.0 탆 or when the FeO ratio in the scale exceeds 80% by volume. If the coiling temperature exceeds 880 占 폚, it may exceed 0.1% by volume, Fe ₂ SiO ₄ (Fealite) may be generated nonuniformly at the interface between the scale and the iron, and the scale may be unevenly peeled And the MD property deteriorates. On the other hand, if the coiling temperature is lower than 750 캜, the FeO ratio can not be ensured by 30% by volume or more, and the MD property is deteriorated. The coiling temperature is preferably 770 DEG C or more and 875 DEG C or less, and more preferably 790 DEG C or more and 860 DEG C or less.

The cooling after the 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, it is possible to prevent the already formed FeO from being converted to Fe ₃ O ₄ by lowering the oxygen fraction or by frequently jetting the gas containing no oxygen, and cooling it, and it is possible to secure the FeO ratio in the scale. The oxygen fraction is preferably 10 vol% or less, more preferably 5 vol% or less, and still more preferably 0 vol% (that is, inert gas only). Examples of the inert gas include argon and nitrogen, and preferably nitrogen. The cooling stop temperature of the cooling to be performed by blowing out the above-mentioned gas is not particularly limited, but it may be cooled to a temperature of, for example, 550 to 650 ° C while spraying the gas, and then cooled 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 secure the strength of the wire rod, 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, if the amount of C becomes excessive, the hot workability at the time of producing the wire is deteriorated. Therefore, the C content was set at 1.2% or less. The C content 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. If the content is too small, the production of Fe ₂ SiO ₄ (featherite) becomes insufficient and the MD property is deteriorated. Therefore, the amount of Si was set to 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, if the amount of Si becomes excessive, excessive production of Fe ₂ SiO ₄ (FeAl) causes not only the MD property to deteriorate remarkably but also a problem such as generation of a surface decarburization layer occurs. Therefore, the amount of Si was 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 ensuring the quenching of the steel and for increasing the strength. In order to exhibit such an effect effectively, the amount of Mn is set to 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 becomes excessive, segregation occurs in the cooling process after hot rolling, and supercooled structure (martensite or the like) which is detrimental to drafting workability tends to be generated. Therefore, the Mn content was set at 1.5% or less. The amount of Mn is preferably 1.4% or less, and more preferably 1.2% or less.

P: not more than 0.02% (not including 0%)

P is an element that deteriorates toughness and ductility of steel. In order to prevent disconnection in a drawing process or the like, the amount of P is set to 0.02% or less. The P content is preferably 0.01% or less, 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 (not including 0%)

S, like P, is an element that deteriorates toughness and ductility of steel. In order to prevent breakage in drawing or subsequent stranding, the amount of S 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 (not including 0%)

N is an element that deteriorates the ductility of steel when the content is excessive. Therefore, the N content was set to 0.005% or less. The N content is preferably 0.004% or less, and more preferably 0.003% or less. The lower limit of the amount of N 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 remainder portion is substantially iron. However, it is a matter of course that inevitable impurities brought in according to the conditions of raw materials, materials, manufacturing facilities, etc. are included in the steel wire rod. In addition, it is also recommended to add the following elements as necessary insofar as the effect of the present invention is not impaired.

Not more than 0.3% Cr (not including 0%) and / or Ni: not more than 0.3% (not including 0%).

Both Cr and Ni are elements that enhance the quenching of the steel and contribute to the improvement of strength. In order to effectively exhibit such action, the amount of Cr is preferably 0.05% or more, and the amount of Ni is preferably 0.03% or more. The more preferable amounts of Cr and Ni are all 0.10% or more, and more preferably 0.12% or more. On the other hand, if the Cr amount and the Ni amount are excessive, the martensite structure tends to occur and the adhesion of the scale to the base metal becomes too high, and the peelability of scale at the time of MD deteriorates. Therefore, it is preferable that the Cr amount and the Ni amount are all 0.3% or less. More preferred amounts of Cr and Ni are all 0.25% or less, and more preferably 0.20% or less.

Cu: not more than 0.2% (not including 0%)

Cu is an element having an action to promote scale separation. In order to effectively exhibit such action, the amount of Cu is preferably 0.01% or more. The amount of Cu is more preferably 0.05% or more, and still more preferably 0.10% or more. On the other hand, when the amount of Cu is excessive, scale separation is excessively promoted, scale is peeled off during rolling, and other scales with thin and high adhesion are generated on the peeling surface, and rust is generated when the wire rod coils are stored and transported . 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.

At least one element selected from the group consisting of Nb, V, Ti, Hf and Zr in a total amount of not more than 0.1% (not including 0%),

Nb, V, Ti, Hf, and Zr all form fine carbonitride and contribute to high strength. To effectively exert such an effect, it is preferable that the amounts of Nb, V, Ti, Hf and Zr are all 0.003% or more. The amount of Nb, V, Ti, Hf and Zr is more preferably 0.007% or more, and still more preferably 0.01% or more. On the other hand, if these elements are excessive, ductility deteriorates, and therefore the total amount thereof is preferably 0.1% or less. The total amount of these elements is more preferably 0.08% or less, and still more preferably 0.06% or less.

Al: not more than 0.1% (not including 0%)

Al is an effective element as a deoxidizer. In order to effectively exhibit such an effect, the amount of Al 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 are increased, and disconnection occurs frequently during drawing processing. Therefore, the amount of Al 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: not more than 0.005% (not including 0%)

B is an element that inhibits the formation of ferrite by being present as free B (compound B not formed) that is solidly dissolved in steel, and is an effective element in high-strength wire rods which require suppression of vertical cracks. To effectively exhibit such action, the amount of B is preferably 0.0001% or more. The amount of B is more preferably 0.0005% or more, and still more preferably 0.0010% or more. On the other hand, if the amount of B becomes excessive, the ductility deteriorates. Therefore, the amount of B is preferably 0.005% or less, more preferably 0.0040% or less, still more preferably 0.0035% or less.

Ca: not more than 0.01% (not including 0%) and / or Mg: not more than 0.01% (not including 0%)

Ca and Mg are both elements that control the shape of inclusions and enhance ductility. Ca also has an effect of enhancing the corrosion resistance of the steel material. In order to effectively exhibit such an effect, it is preferable that both the Ca amount and the Mg amount are 0.001% or more. More preferably, Ca and Mg are both 0.002% or more, and more preferably 0.003% or more. On the other hand, if these elements are excessive, the workability is deteriorated. Therefore, it is preferable that the Ca amount and the Mg amount are all 0.01% or less. The amount of Ca and Mg is more preferably 0.008% or less, and still more preferably 0.005% or less.

Example

Hereinafter, the present invention will be described more specifically by way of examples. The present invention is not limited to the following embodiments, and it is of course possible to carry out the present invention by appropriately modifying it within a range suitable for the purpose described below, and they are all included in the technical scope of the present invention.

A steel having the chemical composition shown in Tables 1 and 2 was dissolved in a usual solvent method and then a billet having a size of 150 mm x 150 mm was prepared and heated in a heating furnace. Thereafter, the primary scale generated in the heating furnace was descaled using high-pressure water, and hot-rolled under the conditions shown in Table 3 (the coiling temperature after hot rolling and the gas used for cooling) Steel wire rods were obtained. The cooling using the gas shown in Table 3 was carried out all the way up to about 600 ° C, and after that, it was allowed to cool in the air.

The obtained steel wire rod was measured by the following method.

(1) Measurement of scale thickness

Samples having a length of 10 mm were taken from each of the front end, the center and the rear end of the coil, and arbitrary three scale cross sections of each sample were observed with a scanning electron microscope (SEM) (observation magnification: 5000 times) . For each measurement point, a 10-point scale thickness was measured at a length of 100 μm in the main direction of the steel wire rod, and the average scale thickness was obtained. The average value of the three points was defined as the scale thickness of each sample. Further, an average value of each sample (front end portion, center portion, and rear end portion of the coil) was calculated and used as the scale thickness of each test No..

(2) Measurement of composition of scale

Samples having a length of 10 mm were collected from each of the front end, the center and the rear end of the coil in the same manner as in the above (1), and X-ray diffraction was performed on arbitrary three scale cross- The ratio (volume%) of FeO and Fe ₂ SiO ₄ was determined from the peak intensity ratio of Fe ₂ SiO ₄ , Fe ₂ O ₃ and Fe ₃ O ₄ . The average value of the three portions was determined as the FeO ratio and the Fe ₂ SiO ₄ ratio of each sample. Further, an average value of each sample (the front end portion, the center portion and the rear end portion of the coil) was calculated, and the FeO ratio and the Fe ₂ SiO ₄ ratio of each test No. were determined.

(3) Measurement of scale removability of rolled material

A sample having a length of 200 mm was sampled from each of the front end portion, the center portion, and the rear end portion of the coil, and the scale of the surface of the steel wire material was blown away by blowing wind to the sample. The appearance before and after the wind was blown away by the digital camera was photographed and the area ratio of the peeled scale was obtained by comparing the both by image analysis.

(4) Measurement of MD property

A sample having a length of 250 mm was sampled from each of the front end portion, the center portion, and the rear end portion of the coil, and strain distortion of 6% was given to the specimen by a tensile tester. After being taken out from the chuck, . The appearance of the appearance before and after the application of the deformation was photographed by a digital camera, and the residual scale area ratio was calculated by comparing the images by image analysis.

The results are shown in Tables 4, 5 and 2.

No. of Tables 4 and 5. 1, 2, 4 to 28, 30 to 32, 34, 35, 37 to 39, 41, 42, 44, 45 and 48 are examples satisfying the requirements of the present invention, Therefore, the MD property is good.

On the other hand, 3, 29, 33, 36, 40, 43, 46, 47, and 49 had poor MD characteristics because the production conditions did not satisfy the requirements of the present invention.

No. 3, 29, 36, 40, 43, 46, and 47 are examples in which hot air is blown out after hot rolling and FeO is changed to Fe ₃ O ₄ during cooling. As a result, the FeO fraction can not be ensured, Deteriorated. No. 33 is an example in which the coiling temperature after hot rolling is high. Since the scale thickness becomes thick, the FeO ratio becomes too large, and the Fe ₂ SiO ₄ ratio becomes high, the MD property deteriorates. No. 49 was an example in which the coiling temperature after hot rolling was low and the FeO ratio could not be secured and the MD property deteriorated. No. 50 to 54 are examples in which the coiling temperature after hot rolling was higher, the scale thickness exceeded 7.0 mu m, the scale peeling ratio of the rolled material was increased, and rust was generated. That is, No. From 50 to 54, it is considered that scales fall off during cooling after hot rolling or during storage and transportation, and rust is generated.

Fig. 2 shows the relationship between the scale thickness and the scale peel ratio of the rolled material. It can be seen that when the scale thickness exceeds 7.0 占 퐉, the scale removal rate of the rolled material becomes large.

While the present invention has been described in detail with reference to specific embodiments thereof, it is evident to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention.

This application is based on Japanese patent application filed on January 7, 2011 (Japanese Patent Application No. 2011-002014, the content of which is incorporated herein by reference).

Since the steel wire material of the present invention is excellent in mechanical descalability after hot rolling (before the drawing process), it is possible to use a wire used for cutting silicon for semiconductor and the like in addition to a tire cord (steel cord, bead wire) It is useful as a material for saws and the like.

Claims (8)

A method for producing a steel wire rod having a scale of 7.0 탆 or less in thickness and FeO ratio in the scale of 30 to 80% by volume and Fe ₂ SiO ₄ ratio of less than 0.1%
C: 0.05 to 1.2% (meaning% by mass, hereinafter the same with respect to the chemical components)
0.01 to 0.5% of Si,
Mn: 0.1 to 1.5%
P: not more than 0.02% (not including 0%),
S: not more than 0.02% (not including 0%),
N: 0.005% or less (not including 0%) and the balance being iron and unavoidable impurities,
After hot rolling, the steel sheet was rolled at 750 to 880 캜,
Wherein the steel wire rod is cooled while spraying a mixed gas of oxygen and an inert gas or an inert gas having an oxygen fraction of less than 20% by volume until the temperature of the steel material after winding up to at least 650 캜 is lowered. The method according to claim 1,
Wherein the steel wire material further contains at least one of Cr: not more than 0.3% (not including 0%) and Ni: not more than 0.3% (not including 0%). 3. The method according to claim 1 or 2,
Wherein the steel wire material further contains 0.2% or less of Cu (not including 0%). 3. The method according to claim 1 or 2,
Wherein the steel wire rod further contains at least one element selected from the group consisting of Nb, V, Ti, Hf and Zr in a total amount of not more than 0.1% (not including 0%). 3. The method according to claim 1 or 2,
Wherein the steel wire rod further contains 0.1% or less Al (not including 0%) of Al. 3. The method according to claim 1 or 2,
Wherein the steel wire material further contains B: 0.005% or less (not including 0%). 3. The method according to claim 1 or 2,
Wherein the steel wire material further contains at least one of Ca: 0.01% or less (not including 0%) and Mg: 0.01% or less (excluding 0%). The method of producing a steel wire rod according to claim 1, wherein the inert gas is nitrogen.

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