JPH05247596A - Wire rod for producing extra fine wire of austenitic stainless steel, the same extra fine wire, and production of the same extra fine wire - Google Patents

Abstract

PURPOSE:To improve workability and to produce an extra fine wire having high strength and excellent in settling resistance by regulating the contents of Al, S, and O in a steel composition so that they satisfy specific relations, performing wiredrawing, and subjecting to heat treatment under specific conditions. CONSTITUTION:In a wire rod for producing extra fine wire of austenitic stainless steel, S, Al, and O are incorporated, by weight, <=0.005%, <=0.005%, and <=0.005%, respectively, into a steel composition. Further, the relation between S and Al satisfies the condition of an equality S>=Al/2 and a structure where the composition of the nonmetallic inclusions in the steel consists of oxysulfide containing, in total, >=1wt.% S is formed. This stainless steel is subjected to wire rod rolling and to a repetition of annealing and wiredrawing, by which an extra fine wire is produced. Successively, at the time of performing heat treatment, wiredrawing before heating is made at >=50% and successive heat treatment is performed at 100-600 deg.C under the condition where the value of (k) represented by k=TX(logt+20)X10<-8> satisfies >=6.5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire rod for producing stainless steel ultrafine wire, the same ultrafine wire and a method for producing the same ultrafine wire, and particularly, when the wire diameter is 500 μm or less, high strength and excellent sagability and excellent Members and parts that require workability, such as communication equipment, computer-related equipment, precision electronic equipment,
The present invention relates to a wire rod for producing an austenitic stainless steel ultrafine wire, a wire for producing the ultrafine wire, and a method for producing the ultrafine wire, which are suitable for wire springs and mini ropes of office equipment or electric equipment.

[0002]

2. Description of the Related Art In recent years, as the weight and size of equipment have been reduced, the diameter of ultrafine wire has become inevitably thin, and wire drawing can be performed to a finer wire. From this point of view, high strength and high sag resistance are required. On the other hand, from the viewpoint of product molding, bending and twisting are often performed, and securing the workability of high-strength ultrafine wires is also an important required characteristic.

Conventionally, general-purpose austenitic stainless steels such as SUS301 and SUS304 have been used for the stainless steel ultrafine wires for the above-mentioned members, but it has become difficult to meet the above-mentioned strict requirements, and oxide-based materials together with the basic components have been used. A non-metallic inclusion is proposed (for example, JP-A-62-290848). However, adjustment of the composition of the oxide-based non-metallic inclusions is sensitive to the composition of raw materials or the operating conditions, and therefore requires an extremely fine control technique. As a result, there is a drawback of causing quality instability, and it has not been widely used. Therefore, development of austenitic stainless steel ultrafine wire having good wire drawability and more stable quality is strongly desired.

[0004]

DISCLOSURE OF THE INVENTION In order to meet the strong demands of the industry, the present invention has been made by the present inventors as a result of extensive studies in view of the problems of conventional austenitic stainless steel ultrafine wires, and as a result, the chemical composition was appropriately adjusted. It was clarified that all the conventional problems can be solved by adjusting and controlling the composition of the material and the composition of non-metallic inclusions and appropriate heat treatment after wire drawing, and the present invention has been completed. Its purpose is to produce austenitic stainless steel extra fine wires that have excellent workability for drawing ultrafine wires, excellent product formability, and high strength and extremely good sag resistance in terms of product performance. The present invention provides a wire rod, an ultrafine wire, and a method for manufacturing the ultrafine wire.

[0005]

The subject matter of the present invention is as follows.

(1) S ≦ 0.005% by weight, A
1 ≦ 0.005%, O ≦ 0.005%, and the relationship between S and Al content satisfies the formula (1),
A wire material for producing an austenitic stainless steel extra fine wire, characterized in that the composition of non-metallic inclusions in the steel is oxysulfide containing 1 wt% or more of S in total.

[S] ≧ [Al] / 2 (1) where [S]; S content in steel (wt%) [Al]; Al content in steel (wt%)

(3) In weight%, S ≦ 0.005%, A
1 ≦ 0.005% and O ≦ 0.005%, and the composition of the content of S and Al is adjusted to satisfy the formula (1).
% Of S or more oxysulfide formed austenitic stainless steel is rolled into a wire rod, followed by annealing / drawing to produce ultrafine wires, and then when heat treated, before the heat treatment. 50% or more, followed by heat treatment at a temperature of 100 ° C. or more and 600 ° C. or less and a condition that the k value represented by the formula (2) is 6.5 or more. A method for producing an austenitic stainless steel extra fine wire, which is characterized.

[S] ≧ [Al] / 2 (1) where [S]; S content in steel (wt%) [Al]; Al content in steel (wt%) k = T × ( logt + 20) × 10 ⁻³ (2) where k: heating coefficient T: heating temperature (K) t: heating time (Hr)

(3) In% by weight, C: 0.05 to 0.15%, Si: 0.2 to 3%, Mn: 0.2 to 3%, S ≤ 0.005%, Ni: 6. 5 to 12%, Cr: 16 to 20%, Al: 0.0005 to 0.005%, N: 0.02 to 0.10%, O ≦ 0.005%, and the content of S and Al The relation satisfies the formula (1),
The total composition of non-metallic inclusions in steel is oxysulfide containing 1 wt% or more of S, and the spring limit value is 70.
An austenitic stainless steel ultrafine wire characterized by having a weight of at least kgf / mm ² .

[S] ≧ [Al] / 2 (1) where [S]; S content in steel (wt%) [Al]; Al content in steel (wt%)

(4) In weight%, C: 0.05 to 0.15%, Si: 0.2 to 3%, Mn: 0.2 to 3%, S ≦ 0.005%, Ni: 6. 5 to 12%, Cr: 16 to 20%, Al: 0.0005 to 0.005%, N: 0.02 to 0.10%, O ≦ 0.005%, and the content of S and Al The composition is adjusted to satisfy the formula (1), and the total composition of non-metallic inclusions in steel is 1 wt.
% Of S or more oxysulfide formed austenitic stainless steel is rolled into a wire rod, followed by annealing / drawing to produce ultrafine wire, and when the heat treatment is performed, the heat treatment is performed. Perform 50% or more of the previous wire drawing, and subsequently perform heat treatment at a temperature of 100 ° C. or more and 600 ° C. or less and a condition that the k value represented by the formula (2) is 6.5 or more. A method for producing an austenitic stainless steel ultrafine wire characterized by.

That is, the present inventors have made a detailed study on the influencing factors on the workability, formability, mechanical properties, etc. of the austenitic stainless steel ultrafine wire and the stainless steel ultrafine wire produced from the wire. As a result, it was clarified that the workability and formability were greatly affected by non-metallic inclusions, while the mechanical properties (sag resistance and strength) were significantly affected by steel quality and heat treatment. Based on this knowledge, it is effective to reduce the amount of non-metallic inclusions as much as possible and then control the composition in order to make them finer and more dispersed during processing. It was clarified that adjustment is important, and that it is effective to set the wire drawing rate within an appropriate range and then perform appropriate heat treatment for sag resistance. The present invention was achieved by combining them.

[0014]

The function of the austenitic stainless steel ultrafine wire according to the present invention will be described. (1) High workability and high formability In order to enable high strength wire drawing and to improve the formability of high strength stainless steel ultrafine wire, it is necessary to reduce the hard non-metallic inclusions that are the starting points of fracture. Required.

Conventionally, as a method of reducing the harmfulness of hard non-metallic inclusions, the amount of oxide non-metallic inclusions has been reduced by reducing the oxygen content to a very low level, and the amount of Al has been reduced to reduce the amount of alumina (Al).
Attempts have been made to reduce the amount of ₂ O ₃ ) -based oxides, or to control the composition of oxide-based inclusions to a low-melting-point SiO ₂ —MnO—Al ₂ O ₃ system. As a result of detailed studies on the generation behavior of non-metallic inclusions or the deformation behavior during processing, the present inventors have found that when extremely low oxygen is used, a hard oxide remains despite the extremely low Al content. It turned out to be the starting point of the crack. This depends on the concentration of Al ₂ O ₃ in the oxide, which indicates that it is not easy to control the composition of oxide inclusions, which has been conventionally said. That is, the oxide-based inclusions are converted to low melting point SiO ₂ --MnO--Al
Controlling to ₂ O ₃ system is based on alloy components (Al, Si, M
n and O) balance or refining conditions (temperature, time, slag composition, etc.) need to be finely controlled, and the temperature is about 1200 ° C when the melting point is lowered, so the quality is practically stable. It was found that there are many problems in industrial production.

Therefore, as a result of further intensive studies, if the morphology of the nonmetallic inclusions is controlled to oxysulfide containing S in the oxide, it can be easily drawn by hot rolling and then finely drawn by wire drawing. The present invention has been completed by finding that it does not become a starting point of fracture because it is divided into two parts, and that the morphology of oxysulfide can be controlled only by adjusting the alloy components (S, Al and O).

(2) Sag resistance and high strength Sag resistance is improved by releasing the strain accumulated by wire drawing. The present inventors have found that low temperature heat treatment at 100 ° C. or higher increases strength and improves sag resistance (spring limit value). On the other hand, when using a stainless steel ultrafine wire as a spring, high strength and high toughness are important issues, and the present invention also takes these points into consideration.

That is, high strength and high toughness are caused by the solid solution strengthening of the interstitial elements C and N and the strain caused by the heat treatment after the wire drawing work for effectively utilizing the dislocations accumulated by the wire drawing work of strength. This is due to the overlapping effect of age hardening.
Here, the strength is increased by alloying a large amount of C and N, which have a strong solid solution hardening action, but on the other hand, addition of a large amount of C and N causes deterioration of toughness, so selection of an appropriate value thereof is important. is there. Further, since the degree of solid solution strengthening and the degree of deterioration of toughness are different between C and N, there is an optimum amount of C and N from the balance of strength and toughness.

It is to be noted that after the stainless steel wire rod is drawn 40
A so-called bluing treatment in which low temperature annealing is performed at 0 to 500 ° C. for 10 to 30 minutes is generally known, but the present inventors heat-treat at a low temperature of 100 ° C. or more for several seconds if strong wire drawing is performed. It has been found that sufficient strain aging can be obtained by simply performing the heat treatment, and the heat treatment in the present invention can control the composition of the non-metallic inclusions and secure the wire drawing workability of the strength brought about by the proper blending of C and N. It is a structurally important requirement and is essentially different from conventional brewing.

Next, in the wire rod for producing an austenitic stainless steel ultrafine wire, the same ultrafine wire and the method for producing the same ultrafine wire of the present invention, the reason why the composition component ratios and the heat treatment conditions are numerically limited will be described. (1) C C has an action of interstitial solid solution in steel to strengthen it, and is the most effective and necessary element in the steel of the present invention. If the content is less than 0.05 wt%, this effect is small, and
If the content exceeds 0.15 wt% and is excessive, Cr carbide precipitates at the grain boundaries to lower the ductility, deteriorating the wire drawability and formability, and lowering the corrosion resistance. Therefore, C is set to 0.05 to 0.15 wt%.

(2) Si Si is added as a deoxidizing agent, and is included for the purpose of positively reducing oxide-based nonmetallic inclusions and controlling the formation of Al ₂ O ₃ -based nonmetallic inclusions. To do. That is, the composition of the non-metallic inclusions that is the base of the present invention is adjusted, and if the content is less than 0.2 wt%, the composition of the non-metallic inclusions is mainly Al ₂ O ₃ and the effect is small. However, if it exceeds 3% and is contained excessively, a δ-ferrite phase is likely to be formed, and the hot rolling property is deteriorated. Therefore, the Si content is set to 0.2 to 3 wt%.

(3) Mn Mn combines with S to form MnS, and combines with O to form MnO.
And is an important element for producing oxysulfide in the present invention, and 0.2 wt% or more is necessary to exert this effect. However, if contained in a large amount, it becomes difficult to form an effective oxysulfide, which deteriorates corrosion resistance and toughness, so the upper limit is 3 w.
It was set to t%. Therefore, the Mn content is 0.2 to 3 wt%
And

(4) S S is an important element in the present invention in order to form oxysulfide having so-called plasticity, which is stretched in hot working and divided in the subsequent cold working.
However, if it is contained excessively, the hot workability deteriorates and the corrosion resistance of the product also deteriorates. Therefore, the upper limit of S is 0.00
It was set to 5 wt%.

Here, an appropriate amount of S is required to form oxysulfide. The present inventors conducted various studies on the deformation behavior of nonmetallic inclusions and found that the S content in nonmetallic inclusions is closely related to the Al content, as shown in FIG. FIG. 2 shows 0.07 wt% C, 0.
50 wt% Si, 1.2 wt% Mn, 0.020 wt%
P, 0.003 wt% S, 8.7 wt% Ni, 18.7
5 wt% Cr, 0.038 wt% N, 0.0008 wt
9 kinds of austenitic stainless steel wire rods (6 mm) with% O as a basic component and changing the balance of S and Al contents.
φ) was manufactured, and further drawn to 2 mmφ, and the behavior of non-metallic inclusions was investigated. Here, the composition analysis of the non-metallic inclusions was performed mainly with a wire rod having a diameter of 6 mm and, for some of them, a wire having a diameter of 2 mm. The size of the non-metallic inclusion was determined by a 2 mmφ line.

As a result, the composition of the non-metallic inclusions stretched and divided during hot working and / or cold working (wire drawing) has a low Al ₂ O ₃ concentration and contains 1 wt% or more of S (the present invention). In oxysulfide). O amount is 0.0050 wt% or less, Al amount is 0.0050
If it is less than wt%, this tendency and the effect are remarkable.

Therefore, formation of oxysulfide is essential in order to make non-metallic inclusions fine and dispersed so as to be harmless to workability. For effective formation of oxysulfide, the amount of S represented by the following formula can be used. Securing is important. [S] ≧ [Al] / 2 (1) That is, by satisfying the expression (1), the S concentration in the non-metallic inclusion becomes 1 wt% or more, and the non-metallic inclusion is oxysulfide having plasticity. Become.

(5) Ni Ni is a basic component of austenitic stainless steel and is an extremely effective element for stably obtaining an austenitic phase at room temperature. It is also an important element for ensuring the toughness of steel and wire drawing workability and formability, and 6.5 wt% or more is necessary to effectively exhibit these effects. On the other hand, the content of Ni in excess of 12 wt% only lowers the strength. Therefore, the content of Ni is set to 6.5 to 12 wt%.

(6) Cr Cr is a basic component for stably obtaining an austenite phase in a proper balance with the amount of Ni and ensuring good corrosion resistance. Further, the steel of the present invention improves the strength and Young's modulus of the steel. If the content is less than 16% by weight, the above effect is small, and if the content of Cr exceeds 20% by weight, δ ferrite is formed, the hot workability is deteriorated, and product defects after rolling frequently occur. Therefore, the Cr content is 16 to 2
It was set to 0 wt%.

(7) Al Al is added as a deoxidizing agent. That is, if proper deoxidation with Al is not performed, hard Cr ₂ O ₃ , SiO ₂ ,
SiO ₂ —MnO or a composite oxide of these is formed,
It causes deterioration of workability. Therefore, the basic oxide of oxysulfide in the present invention is SiO ₂ —MnO—A.
A proper amount is necessary for the formation of the l ₂ O ₃ -based oxide.
However, excessive addition is not preferable because it forms a hard Al ₂ O ₃ -based oxide and has an adverse effect. Therefore, as an appropriate amount of Al to make the above effect effective, 0.005
It was set to be wt% or less.

(8) N N is an austenite-forming element similar to C, and is an important element in the present invention for strongly strengthening the austenite phase as an interstitial solid solution effect in steel. Is less than 0.02 wt%, the desired effect cannot be obtained. On the other hand, when the content exceeds 0.10 wt% and is excessively contained, the toughness or the ductility is extremely reduced, and it becomes difficult to draw an ultrafine wire and a problem occurs in the formability of the product. Therefore, the N content is set to 0.02 to 0.10 wt%.

(9) O 2 O is preferable because it forms oxide inclusions.
However, the extreme reduction is disadvantageous in terms of steelmaking cost. On the other hand, the upper limit of the amount of O is 0.0050 wt% for the stable formation of oxysulfide in the present invention. Therefore, the content of O is set to 0.0050 wt% or less.

Next, the reason for limiting the heat treatment conditions after wire drawing, which is an important requirement for improving the sag resistance in the present invention, will be described in detail. The sag resistance is generally expressed by a plastic deformation strain amount or a spring limit value. That is, in terms of the spring limit value, the higher this value, the better the sag resistance, and the higher the performance of the spring and the like.

Therefore, one example of the chemical component of the present invention is
0.08wt% C, 0.52wt% Si, 0.85wt
% Mn, 0.020 wt% P, 0.003 wt% S,
8.7 wt% Ni, 18.90 wt% Cr, 0.002
0 wt% Al, 0.0010 wt% O, 0.052 wt
150% for wire rod rolling by melting and casting austenitic stainless steel with% N and the balance unavoidable impurities
A mm □ billet was manufactured and the following experiment was conducted.

That is, after heating the billet at 1200 ° C., it was hot rolled into a wire rod having a diameter of 6 mm. Then, after pickling and descaling, wire drawing is performed to a diameter of 2 mm, followed by bright annealing and wire drawing to obtain a diameter of 1 mm.
It was an ultrafine wire of 50 μmφ. The ultrafine wire was heat-treated at various temperatures and times to measure the spring limit value. The result is shown in FIG. In the figure, k is a factor of the heating temperature and the heating time and is expressed by the equation (2).

K = T × (logt + 20) × 10 ⁻³ (2) where k: heating coefficient T: heating temperature (K), t: heating time (Hr) As is clear from FIG. The spring limit value is improved by increasing the k value of the condition. It can be seen that this effect is remarkable when the k value is 6.5 or more.

As a result of the above, from the viewpoint of sag resistance,
The k value represented by the equation (2) was set to 6.5 or more. By the way, the k value is a factor of heating temperature and time, and a low temperature requires a long time. The lower limit was set to 100 ° C. as the industrially stable production time. On the other hand, the higher the temperature, the shorter time the purpose can be achieved, but if the temperature exceeds 600 ° C., there is a tendency for softening, scale formation and carbide precipitation occur, and toughness decreases. Therefore, the heating temperature is 100
The temperature was set to 600 ° C.

FIG. 1 shows the influence of the area reduction ratio of the wire drawing process before the heat treatment for obtaining a high spring limit value. As is clear from this figure, if the wire drawing area reduction ratio before the heat treatment is 50% or more, the required spring limit value can be obtained. Therefore, in consideration of industrial productivity, the area reduction rate of the wire drawing process before the heat treatment is limited to 50%. Although this effect is exhibited whether the heat treatment atmosphere is the atmosphere, reducing or non-oxidizing atmosphere, the air treatment is preferable from the viewpoint of equipment and productivity. However, depending on the treatment conditions, the surface may be discolored due to oxidation. On the other hand, in the case of a nitrogen atmosphere, nitriding is effective because it is possible to obtain high strength and a high spring limit value, but it is effective, but depending on the processing conditions, the toughness may decrease. Therefore,
The heat treatment atmosphere should be selected according to the production scale, equipment, etc., and is not particularly limited.

[0038]

EXAMPLES The features of the high-strength, high-toughness austenitic stainless steel ultrafine wire according to the present invention, which is excellent in sag resistance, will be described with reference to examples. Austenitic stainless steel having the chemical composition shown in Table 1 was melted in a vacuum melting furnace, and the steel ingot obtained by ingoting was heated and hot-rolled at 1200 ° C. to obtain a wire having a diameter of 6 mmφ. Pickling the obtained wire rod
After annealing, after drawing wire to make 2mmφ intermediate wire,
Degreasing, bright annealing, and subsequent wire drawing are performed to produce ultrafine wires with a wire diameter of 150 μmφ.
After heat-treating the ultrafine wire under various conditions, various mechanical properties (spring limit value, tensile strength, elongation, bending workability, etc.) were investigated. Here, the evaluation of the non-metallic inclusions was performed using an energy dispersive analyzer and an image analyzer. Also,
The evaluation of the wire drawability was performed by the presence or absence of disconnection in the wire drawing process from 2 mmφ to 150 μmφ.

Table 1 is an example in which the relationship between non-metallic inclusions and wire drawability was first observed. Material Nos. 1 to 7 shown in Table 1 are steels of the present invention, and Nos. 8, 9 and 10 are comparative steels. Since all of the chemical components of the steel of the present invention are adjusted, the non-metallic inclusions observed in the intermediate wire of 2 mmφ are fine and therefore have good wire drawability. On the other hand, since the No. 8 steel contains an extremely large amount of Al of 0.006 wt%, large inclusions due to the hard Al ₂ O ₃ based oxide remain, and Oxysulfide is not formed in the steel because the S content is low, and the hard composite oxide remains. Further, since the No. 10 steel has an excessive amount of O, a large amount of oxide remains and the number is large. For this reason, all of the steel Nos. 8 to 10 are broken by wire drawing.

Table 2 shows the relationship between the sag resistance (spring limit value) and the heat treatment, with the wire drawing ratio being constant (99.4%). Steel, and 30 to 34 steels are comparative steels. Wire drawing rate of 50
%, The spring limit value is 70 kgf /
mm ² or more. This is significantly higher than the conventional one. On the other hand, when the heat treatment is not performed or the heat treatment is insufficient (k value is less than 6.5), the spring limit value is low and the heat treatment temperature is 6
It can be seen that when the temperature is higher than 50 ° C. (No. 34 steel), it softens and the spring limit value decreases. From the above examples, it is clear that the steel of the present invention has extremely good sag resistance.

Table 3 is an example showing the relationship between the spring limit value and the wire drawing rate. No. 35-38 steel is 50% wire drawing rate
The steels of the present invention described above, and the steel Nos. 39 and 40 are comparative steels. Nos. 35 and 36 steels have wire drawing ratios of 60% and 70.3%, so the spring limit value is 70 kgf /
It exceeds mm ² . On the other hand, in No. 39 steel, the wire drawing rate was 45.7% despite the high k value of 8.1.
Therefore, the spring limit value is low.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

[Table 3]

[0045]

As described above, according to the present invention, the existing melting and refining technology can be used to easily manufacture austenitic stainless steel ultrafine wire which is stable, has high strength, and has good workability. In addition, the product has outstanding sag resistance and excellent moldability, and can provide austenitic stainless steel ultrafine wires suitable for precision equipment members, including ultrafine wires for springs. Yes, it has an extremely large effect on the industry.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between a wire drawing area reduction rate and a spring limit value after heat treatment.

FIG. 2 is a diagram showing a region where good oxysulfide is obtained from the relationship between the amount of Al and the amount of S in steel.

FIG. 3 is a diagram showing a relationship between a heating coefficient (k) and a spring limit value.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hidehiko Sumitomo 3434 Shimada, Hikari City, Yamaguchi Prefecture Nippon Steel Works Hikari Steel Co., Ltd.

Claims (4)

[Claims] 1. By weight%, S ≦ 0.005%, Al ≦ 0.005%, O ≦ 0.00
5%, and the relationship between S and Al content satisfies the formula (1),
A wire material for producing an austenitic stainless steel extra fine wire, characterized in that the composition of non-metallic inclusions in the steel is oxysulfide containing 1 wt% or more of S in total. [S] ≧ [Al] / 2 (1) where [S]; S content in steel (wt%) [Al]; Al content in steel (wt%) 2. In weight%, S ≦ 0.005%, Al ≦ 0.005%, O ≦ 0.00
The content of non-metallic inclusions in steel is adjusted to 1 wt% by adjusting the composition to contain 5% and the relation between S and Al content satisfying formula (1).
% Of S or more oxysulfide formed austenitic stainless steel is rolled into a wire rod, followed by annealing / drawing to produce ultrafine wires, and then when heat treated, before the heat treatment. 50% or more, followed by heat treatment at a temperature of 100 ° C. or more and 600 ° C. or less and a condition that the k value represented by the formula (2) is 6.5 or more. A method for producing an austenitic stainless steel extra fine wire, which is characterized. [S] ≧ [Al] / 2 (1) where [S]; S amount in steel (wt%) [Al]; Al amount in steel (wt%) k = T × (logt + 20) × 10 ⁻³ (2) where k: heating coefficient T: heating temperature (K) t: heating time (Hr) 3. By weight%, C: 0.05 to 0.15%, Si: 0.2 to 3%, Mn: 0.2 to 3%, S ≦ 0.005%, Ni: 6.5. ˜12%, Cr: 16-20%, Al: 0.0005-0.005%, N: 0.02-0.10%, O ≦ 0.005%, and the relationship between S and Al content. Satisfies the formula (1),
The total composition of non-metallic inclusions in steel is oxysulfide containing 1 wt% or more of S, and the spring limit value is 70.
An austenitic stainless steel ultrafine wire characterized by having a weight of at least kgf / mm ² . [S] ≧ [Al] / 2 (1) where [S]; S content in steel (wt%) [Al]; Al content in steel (wt%) 4. By weight%, C: 0.05 to 0.15%, Si: 0.2 to 3%, Mn: 0.2 to 3%, S ≦ 0.005%, Ni: 6.5. ˜12%, Cr: 16-20%, Al: 0.0005-0.005%, N: 0.02-0.10%, O ≦ 0.005%, and the relationship between S and Al content. Are adjusted to satisfy the formula (1), and the total composition of the non-metallic inclusions in the steel is 1 wt.
% Of S or more oxysulfide formed austenitic stainless steel is rolled into a wire rod, followed by annealing / drawing to produce ultrafine wire, and when the heat treatment is performed, the heat treatment is performed. Perform 50% or more of the previous wire drawing, and subsequently perform heat treatment at a temperature of 100 ° C. or more and 600 ° C. or less and a condition that the k value represented by the formula (2) is 6.5 or more. A method for producing an austenitic stainless steel ultrafine wire characterized by. [S] ≧ [Al] / 2 (1) where [S]; S amount in steel (wt%) [Al]; Al amount in steel (wt%) k = T × (logt + 20) × 10 ⁻³ (2) where k: heating coefficient T: heating temperature (K) t: heating time (Hr)