KR101401625B1 - Precipitation hardening metastable austenitic stainless steel wire excellent in fatigue resistance and method for producing the same - Google Patents

Abstract

Stable austenitic stainless steel wire and steel wire which are precipitation hardening type materials for high strength and high corrosion resistant products and to greatly improve both strength and fatigue resistance of conventional high strength and high corrosion resistance products, 0.1 to 4.0% of Si, 0.1 to 10.0% of Mn, 3.0 to 9.0% of Ni, 13.0 to 19.0% of Cr, 0.1 to 4.0% of Mo, 0.35 to 3.0% of Al, (A) 0.01 to 0.20% of Ti, 0.05% or less of N and 0.004% or less of O, the balance being Fe and unavoidable impurities, and having an Md30 value of -10 to 70, Stable Nb value of not less than 0.10, and a tensile strength of not less than 2000 N / mm < 2 >, and a production method therefor, which is excellent in fatigue resistance, and a metastable austenitic stainless steel wire. 0.05 to 2.0% of V, 0.05 to 2.0% of W, 0.05 to 2.0% of W, 0.05 to 2.0% of Ta, at least one of Co, 0.1 to 4.0% %, B: 0.005 to 0.015%, Ca: 0.0005 to 0.01%, Mg: 0.0005 to 0.01%, and REM: 0.0005 to 0.05%. Further, aging treatment is performed in a nitrogen atmosphere at 300 to 600 캜.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precipitation hardening type metastable austenitic stainless steel wire having excellent fatigue resistance and a method of manufacturing the same.

 The present invention relates to a product having excellent tensile strength of 2000 N / mm < 2 > or more, excellent in fatigue resistance, such as a spring, and excellent in high strength and fatigue resistance. The present invention controls Al, Mo, Ti, O, N and the like to suppress coarse inclusions, And a precipitation hardening type metastable austenitic stainless steel wire in which the surface layer compression residual stress is controlled by controlling the precipitate.

Conventionally, a high strength stainless steel product formed from a high strength stainless steel wire and having excellent spring fatigue has been processed and molded using stainless steel wire materials of SUS304 and SUS316. The fatigue of these products is required to have fatigue characteristics in the repeated bending direction of the steel wire, or in the twisting direction. However, there is a drawback that the product processed from such steel wire rod has a fatigue strength lower than that of ordinary steel wire. Therefore, a metastable austenitic stainless steel wire for a high strength spring having a tensile strength of 2000 N / mm < 2 > or more and defining hydrogen and crystal grain diameter has been proposed (Patent Document 1). However, according to the study by the inventors of the present invention, improvement in fatigue characteristics can be obtained, but the target fatigue strength (for example, rotational bending stress ≥ 500 N / mm 2) is not satisfied.

On the other hand, in order to improve the fatigue strength, aging treatment and precipitation hardening treatment are effective, and high strength springs in which Mo, Co and N are added to SUS304 system are subjected to low temperature annealing at 500 to 550 占 폚 (Patent Document 2 below) , Cu, Mo, and the like have been added to austenitic precipitation hardening type stainless steel (Patent Document 3).

Further, meta-stable austenitic stainless steels excellent in fatigue resistance by suppressing oxygen and containing N, Mo, Ti, Nb and the like and controlling the amount of processed organic martensite have been proposed (Patent Document 4). Further, a high strength steel sheet in which Mo and Ti are added to a metastable austenitic stainless steel has been proposed (Patent Document 5 below). Further, a high-strength heat-resistant steel sheet in which Mo and Al are added to a metastable austenitic stainless steel has been proposed (Patent Document 6). However, all of the required strength and endurance characteristics (bending of the steel wire or fatigue characteristics in the torsional direction) did not coincide.

Therefore, in the conventional high-strength stainless steel, sufficient strength and fatigue characteristics (bending of the steel wire or fatigue characteristics in the torsional direction) can not be obtained.

Patent Document 1: Japanese Patent Publication No. 4212553 Patent Document 2: Japanese Patent Publication No. 4080321 Patent Document 3: Japanese Patent Publication No. 4327601 Patent Document 4: JP-A-5-279802 Patent Document 5: Japanese Laid-Open Patent Publication No. 2001-131713 Patent Document 6: JP-A-9-143633

It is an object of the present invention to provide a precipitation hardening metastable austenitic stainless steel wire which is a material for high strength and high endurance products and to provide a high strength and high endurance steel wire with greatly improved strength and fatigue resistance It is on.

DISCLOSURE OF THE INVENTION The inventors of the present invention have made various studies to solve the above problems, and as a result, have found that precipitation hardening type metastable austenitic stainless steels can be obtained by 1) a combination of Al and Mo and controlling the amount of processed organic martensite, And 2) controlling the relationship between Al, Ti, and N amount to suppress coarse nitride, and 3) aging the product in a nitrogen atmosphere to give surface compressive residual stress, It has been found that while retaining the strength characteristics, the endothelial property is dramatically increased. The present invention has been made on the basis of the above-described findings, and its essential points are as follows.

(1) A ferritic stainless steel comprising, by mass%, 0.02 to 0.15% of C, 0.1 to 4.0% of Si, 0.1 to 10.0% of Mn, 3.0 to 9.0% of Ni, 13.0 to 19.0% of Cr, 0.1 to 4.0% : 0.35 to 3.0%, Ti: 0.01 to 0.20%, N: 0.05% or less and O: 0.004% or less, the balance being Fe and unavoidable impurities,

Wherein an Md30 value represented by the following formula (a) is -10 to 70, an Ng value defined by the following formula (b) is N or more and 0.10 or less, and a tensile strength is 2000 N / Precipitation hardening type metastable austenitic stainless steel wire.

Md30 = 551-462 (C + N) -9.2Si-8.1Mn-29 (Ni + Cu) -13.7Cr-18.5Mo (a)

Ng = 0.002 / (Al x Ti) (b)

(2) A precipitate-setting type metastable austenitic stainless steel wire excellent in fatigue resistance as described in (1), wherein the amount of martensite is not less than 25% by volume and less than 85% by volume.

(3) The steel sheet according to (1), further comprising at least one of V: 0.05 to 2.0%, Nb: 0.05 to 2.0%, W: 0.05 to 2.0% and Ta: 0.05 to 2.0% Or the precipitation hardening type metastable stable austenitic stainless steel wire excellent in fatigue resistance described in (2).

(4) A precipitate-setting type metastable stable austenitic stainless steel wire having excellent fatigue resistance according to any one of (1) to (3), further comprising 0.1 to 4.0% of Co by mass%.

(5) The precipitation-hardening metastable-stable austenitic stainless steel wire according to any one of (1) to (4), further comprising Cu in an amount of 0.1 to 2.0% by mass.

(6) A precipitate-setting type metastable stable austenitic stainless steel wire according to any one of (1) to (5), further comprising 0.0005 to 0.015% of B in terms of mass%.

(7) The steel according to any one of (1) to (6), further comprising at least one of Ca: 0.0005 to 0.01%, Mg: 0.0005 to 0.01% and REM: A precipitation hardening metastable austenitic stainless steel wire excellent in fatigue resistance described in one.

(8) A method for producing a stainless steel wire according to any one of (1) to (7), which is characterized in that an aging treatment is carried out at 300 to 600 ° C after cold working to form a precipitation hardening type metastable austenitic system A method of manufacturing a stainless steel wire.

(9) A process for producing a precipitation hardening metastable austenitic stainless steel wire excellent in fatigue resistance described in (8), wherein the aging treatment is carried out in a nitrogen atmosphere.

(10) A spring as set forth in any one of (1) to (7), wherein the spring is formed of a precipitation hardening type metastable austenitic stainless steel wire excellent in fatigue resistance.

The metastable austenitic stainless steel wire having excellent fatigue resistance according to the present invention has an excellent endothelial property in addition to a strength of not less than 2000 N / mm 2, At an inexpensive price.

Fig. 1 is a graph showing the effect of Mo and Al on the fatigue strength. Fig.
2 is a graph showing the influence of the Ng value and the N amount on the fatigue strength.

First, the reasons for limitation described in (1) and (2) of the present invention will be described.

C is added in an amount of 0.02% or more (hereinafter, all mass%) in order to obtain high strength after drawing. However, if it is added in excess of 0.15%, coarse Cr carbide precipitates in the grain boundaries, the ductility tends to deteriorate and the endothelial property deteriorates, so the upper limit is set to 0.15%. The preferred range is 0.04 to 0.12%.

Si is added by 0.1% or more for deoxidation. However, when it is added in an amount exceeding 4.0%, the effect is not only saturated but also deteriorates in productivity, deterioration of the softening property and deterioration of endothelium properties, so the upper limit is 4.0%. The preferred range is 0.5 to 2.0%.

Mn is added by 0.1% or more for deoxidation. However, if it is added in an amount exceeding 10.0%, the strength is lowered and the endothelial property deteriorates. Therefore, the upper limit is set to 10.0%. The preferred range is 0.5 to 5.0%.

Ni is added in an amount of 3.0% or more in order to secure looseness and improve the endothelial property. However, if it exceeds 9.0%, the Md30 value decreases, the strength decreases, and the endothelial property deteriorates. Therefore, the upper limit is set to 9.0%. The preferred range is 4.0 to 8.0%.

Cr is added in an amount of 13.0% or more to ensure corrosion resistance. However, if it is added in excess of 19.0%, the fatigue strength deteriorates due to deterioration in the softening property, so the upper limit is set at 19.0%. The preferred range is 14.0 to 18.0%.

Mo is an effective element for micro-precipitation of Mo-based fine intermetallic clusters by aging treatment at 300 to 600 ° C after sintering to enhance the strength and endothelial property without inhibiting the softening. More than 0.1% of Mo is added. However, if it is added in an amount exceeding 4.0%, the effect is not only saturated, but also deteriorates the properties of the endothelium by lowering the softening property. The preferred range is 0.5 to 2.5% or less.

Al is added as an effective element for fine precipitation of a fine Al-based intermetallic compound by aging treatment at 300 to 600 ° C after drawing to improve the fatigue resistance without deteriorating the softening property and 0.35% or more. However, even if it is added in an amount exceeding 3.0%, the effect becomes saturated, and conversely, the softening property deteriorates and the endothelial property deteriorates. Therefore, the upper limit is set to 3.0%. The preferred range is 0.5 to 15%. A more preferable range is 0.7 to 1.3%.

Ti is an element that improves the endothelial property with inhibition of N and O. It is added in an amount of 0.01% or more in order to prevent precipitation of coarse AlN and improve the endothelial property. However, when it is added in excess of 0.20%, coarse Ti precipitates (TiN, Ti oxide, etc.) are produced and the upper limit is set to 0.20% because the endothelial property deteriorates. A preferable range is from 0.03 to less than 0.10%.

N is an element contributing to the strength, but generates coarse nitride such as AlN and TiN and deteriorates the endothelial property. Therefore, it is limited to 0.05% or less in order to suppress coarse nitride. The preferred range is 0.005 to 0.03%.

O suppresses the formation of coarse oxides and improves the endothelial property, so that it is limited to 0.004% or less together with control of Ti and N content. The preferred range is 0.0003 to 0.003%.

The metal phase of the steel wire of the present invention is composed of an austenite phase and a martensite phase generated by a cold working to be described later. Of these, the proportion of the martensite phase is limited to not less than 25% by volume in order to improve the strength and endothelial characteristics of the steel wire and the steel strip. However, if it exceeds 85% by volume, the softening property deteriorates and the endothelial property deteriorates. Therefore, the upper limit is preferably limited to less than 85% by volume, more preferably 35 to 65% by volume.

The Md30 value is an index obtained by examining the relationship between the amount of the processed organic martensite after the drawing and the component, and it is necessary to control the Md30 value in order to secure high strength and ductility. When the Md30 value is less than -10, the stability of the austenite phase is increased, not only the strength is not increased in the drawing process but also the amount of precipitation strengthening carried out at 300 to 600 占 폚 is also reduced and the endothelial property is deteriorated. On the other hand, when the Md30 value is more than 70, excessive drawing of the processed organic martensite phase is caused in the drawing process, resulting in deterioration of the smoothness after drawing and deterioration of the endothelial characteristics. Therefore, the Md30 value is limited to -10 to 70. The preferred range is 10 to 60. A more preferred range is 20 to 50. [

The Ng value is an index obtained by investigating the relationship between the amount of Al, Ti and N and the deterioration of the endothelial property due to the formation of coarse nitride. As shown in Examples described later, coarse nitride (AlN, TiN or the like) is produced when the Ng value is smaller than the N amount, and the endothelial characteristic deteriorates. Therefore, the Ng value is controlled so as to be N or more. On the other hand, when the Ng value is larger than 0.10, the precipitation hardening degree is small and the strength is lowered, so the upper limit value is set to 0.10. Preferably 0.08 or less. The tensile strength of the steel wire greatly affects the endothermic characteristics. If the tensile strength of the steel wire is more than 2000 N / mm < 2 > Therefore, the tensile strength of the steel wire is limited to not less than 2000 N / mm < 2 >. The preferred range is 2200 to 3500 N / mm < 2 >.

Next, the reasons for limitation described in (3) of the present invention will be described.

0.05 to 2.0% of N, 0.05 to 2.0% of N, 0.05 to 2.0% of W, V, Nb, W and Ta, if necessary, in order to form carbonitride to fine grain size and improve endothelial characteristics. %, And Ta: 0.05 to 2.0%. However, if it is added beyond the upper limit, coarse inclusions are produced, looseness is lowered, and endothelial property deteriorates. The preferred range of each element is 0.1 to 1.0%.

Next, the reasons for limitation described in (4) of the present invention will be described.

Co is added in an amount of 0.1% or more, if necessary, in order to secure the softness and improve the endothelial property. However, when it is added in an amount exceeding 4.0%, the strength is lowered and the endothelial property deteriorates. Therefore, the upper limit is 4.0%. The preferred range is 0.5 to 3.0%.

Next, the reason for the limitation described in (5) of the present invention will be described.

Cu is an effective element for finely precipitating a fine Cu-based intermetallic compound by aging treatment at 300 to 600 ° C after the drawing, but it is an effective element for improving the fatigue resistance by increasing the strength without deteriorating the softening property. . However, if it is added in an amount of 2.0% or more, on the contrary, it softens and deteriorates the endothelial property. Therefore, the upper limit is set to less than 2.0%. The preferred range is 0.5 to 1.5%.

Next, the reason for the limitation described in (6) of the present invention will be described.

B is added in an amount of 0.0005% or more, if necessary, in order to improve the hot-kneading and toughness. However, when boron is added in an amount exceeding 0.015%, boride is generated, and conversely, the softening property deteriorates and the endothelial property deteriorates. Therefore, the upper limit is set to 0.015%. The preferred range is 0.001 to 0.01%.

Next, the reasons for limitation described in (7) of the present invention will be described.

Ca, Mg, and REM are added to at least one of Ca: 0.0005 to 0.01%, Mg: 0.0005 to 0.01%, and REM: 0.0005 to 0.05% for deoxidation, if necessary. However, when added above each upper limit, coarse inclusions are formed and the endothelial property is deteriorated.

Next, the reasons for limitation described in (8) of the present invention will be described.

In the production of steel wire or steel strip excellent in fatigue resistance according to the present invention, cold wire drawing (30 to 90%), cold rolling (30 to 90%) and heat treatment, which are usually carried out from hot rolled steel wire rod or hot rolled steel wire Is economically effective.

At this time, the wires usable in the present invention may be those satisfying the composition, the Md30 value range and the Ng value range of the steel wire of the present invention described above.

As described above, aging treatment is performed after the cold working so as to finely deposit Al, Mo, Cu-based fine precipitates or clusters, to increase the strength without deteriorating the softening property and improve the endothelial property. At this time, the precipitation strengthening is insufficient at a temperature lower than 300 ° C, and becomes excessive when the temperature exceeds 600 ° C. For this reason, the temperature is limited within the range of 300 ° C to 600 ° C. The temperature is preferably 400 to 550 占 폚. When the aging treatment time is less than 3 minutes, the precipitation strengthening is insufficient, and when the aging treatment time exceeds 100 hours, the aging treatment becomes effective. Therefore, the aging time ranges from 3 minutes to 100 hours.

Next, the reasons for limitation described in (9) of the present invention will be described.

In order to improve the fatigue resistance property, it is effective to impart surface compressive residual stress, and it is effective to agglomerate the surface layer by nitrogen to solidify the surface layer or to produce a fine nitride. Therefore, if necessary, an aging treatment is performed in a nitrogen atmosphere. Preferably, it is carried out under a nitrogen partial pressure of 0.5 to 1.0 atm in an atmosphere of anoxidization.

Next, the reasons for limitation described in (10) of the present invention will be described.

The stainless steel wire having excellent fatigue resistance of the present invention can be particularly suitably used as a spring product. Since these products are particularly required to have fatigue resistance, the significance of the present invention is significant. When used as a spring product, the above-described steel wire rod or hot-rolled steel strip (steel sheet) is subjected to cold drawing (machining rate of 30 to 90%), cold rolling (machining rate of 30 to 90%), combination of heat treatment, coiling, To perform cold working in a desired shape, and then aging treatment is carried out.

Hereinafter, embodiments of the present invention will be described. The chemical compositions of the steels of the examples are shown in Tables 1 and 2 (continued from Table 1).

These chemical composition steels were obtained by casting a cast steel having a diameter of 180 mm on a 100 mm vacuum melting furnace, assuming an AOD solvent which is an inexpensive solvent process for stainless steels, hot roll rolling to a cast steel of φ5.5 mm, The hot rolling was terminated at 1000 占 폚. Thereafter, as solution treatment, it was held at 1,050 占 폚 for 30 minutes and then water-cooled and pickled to obtain wire rod steel. Thereafter, cold drawing was carried out to a diameter of 3.0 mm, intermediate strand annealing was carried out at 1050 캜, and cold drawing was carried out down to 1.5 mm continuously. Thereafter, the steel sheet was subjected to aging treatment at 450 캜 for 30 minutes in the atmosphere to obtain a product of a high strength stainless steel wire.

The mechanical properties, martensite amount and fatigue strength of the steel wire products were also evaluated. The evaluation results are shown in Tables 3 and 4 (continued in Table 3).

The mechanical properties of the steel wire were evaluated by the tensile strength and the reduction ratio of the fracture surface in the tensile test of JIS Z 2241. In the product of the steel wire of the present invention example, all of them are 2000 N / mm 2 or more, the fracture section reduction rate is 30% or more, and the strength and ductility are excellent.

The amount of martensite (α ') in the steel wire was determined by the following formulas (A) to (C) by measuring the saturation magnetization value when a magnetic field of 10 000 Oe was applied to the direct current magnetic flux meter.

α 'amount (vo1.%) = σs / σs (bcc) × 100 (A)

σs; Saturation magnetization value (T),? S (bcc); Saturation magnetization value (calculation value) when 100% α 'transformation occurs

? s (bcc) = 2.14-0.030 Creq ----------------- (B)

(C + N) + 1.25P + 2.91S + 1.85A1 + 1.07V (Cre) = Cr + 1.8Si + Mo + 0.5Ni + 0.9Mn +

In the steel wire product of the present invention, the amount of martensite is preferably in the range of 25% by volume or more and less than 85% by volume.

The fatigue characteristics of the steel wire were evaluated in Nakamura type rotary bending fatigue test by applying a rotation bending stress of 500 and 600 N / mm 2, and applying a rotation of 10 ⁵ times to evaluate whether or not the steel wire was broken. The case where both of the stresses were not broken was evaluated as good (?), The case where only 500 N / mm 2 was not broken was evaluated as good (?), And the case where all the stresses were broken was evaluated as poor (X). The scope of the present invention is as follows. The fatigue characteristics of the steel wires 1 to 42 were? Or?, And the fatigue characteristics were excellent. Particularly, when not subjected to a breaking bending stress of 600 N / mm < 2 >, it indicates that the steel has an endothelial property equal to or greater than that of a piano wire, and thus it is possible to use it as a substitute for a piano wire which is considered difficult in the conventional stainless steel wire. Therefore, it is very effective in industry.

Ex. 4 to 15, 27, and 28, and Comparative Examples 48 to 53, 60, and 61, the influence of Mo and Al on the fatigue strength was examined. The present invention has excellent fatigue strength. The fatigue strength is particularly excellent in the range of 0.5 to 1.5% of Al and 0.5 to 25% of Mo.

In addition, according to the present invention. 16 to 21; 73 to 77, the evaluation results are shown in Fig. 2 by examining the influence of the Ng value and the N amount on the fatigue strength. The fatigue strength is particularly excellent in the range of Ng N and N: 0.03% or less. From these results, it can be seen that when the relationship between Al and Mo is in the appropriate range and the relation between Ng and N is controlled within a suitable range, the rotational bending stress is more than 600 N / mm < 2 > .

On the other hand, 44 to 81, the component deviates from the present invention and is inferior in deoxidation failure, poor corrosion resistance and fatigue characteristics.

The corrosion resistance was evaluated by whether or not the surface layer of the steel wire was water repellent after polishing the surface layer to # 500 and spray test for 100 hours according to the salt spray test of JIS Z 2371. Comparative Example No. 1 46 had water repellency and poor corrosion resistance. The other embodiments were non-repellent, so there was no problem.

Comparative Example No. 1 80, and 81 satisfy the relationship of Ng value and N by satisfying the general purpose high-purity ferritic stainless steel or austenitic stainless steel (SUS321), but the other components are not satisfied, and the strength and martensite amount satisfy the present invention Out of range, fatigue strength is low. In these steels, Al is added for deoxidation, Ti is fixed to C and N to prevent Cr carbide, and N is reduced to prevent sensitization. Therefore, precipitation hardening and coarse nitride of the present invention can be prevented, It differs from the basic idea of improving strength.

Next, the influence of the aging temperature described in (8) of the present invention is shown.

The A and E steels shown in Table 1 were subjected to cold drawing to a diameter of 1.5 mm by the method described in the next paragraph of Table 2 and finally subjected to an aging treatment at 250 to 700 ° C for 30 minutes, Were evaluated. The evaluation results are shown in Table 5.

Ex. 1, 5, and 82 to 85, aging treatment was performed at 300 to 600 ° C, tensile strength was more than 2000 N / mm 2, and fatigue characteristics were excellent. On the other hand, 86 to 91, the aging temperature was out of the range of the present invention, and the tensile strength and fatigue characteristics were deteriorated.

Next, the effect of the atmosphere of the aging treatment described in (9) of the present invention is shown.

The B and D steels shown in Table 1 were subjected to cold drawing to a diameter of 1.5 mm by the method described in the next paragraph of Table 2 and finally subjected to an aging treatment at 450 캜 for 30 minutes in a nitrogen atmosphere of air or oxygen , And the influence of the atmosphere was evaluated. The evaluation results are shown in Table 6.

Ex. In the range of 92 to 95, the aging treatment is performed in a nitrogen atmosphere to improve the fatigue characteristics because of the surface compressive residual stress, and the aging treatment in the nitrogen atmosphere is effective for fatigue characteristics.

As can be seen from each of the above examples, the precipitation hardening type metastable austenitic stainless steel wire rod and steel wire for high strength and high corrosion resistance products excellent in endothelial property can be produced at low cost, By performing the precipitation hardening treatment after processing, it is possible to impart excellent endothelial property in addition to the strength of not less than 2000 N / mm < 2 >, and it is extremely useful industrially since it is possible to provide a product with excellent weight reduction and durability at low cost.

Claims (10)

In terms of% by mass,
C: 0.02 to 0.15%
Si: 0.1 to 4.0%
Mn: 0.1 to 10.0%
3.0 to 9.0% of Ni,
Cr: 13.0 to 19.0%
Mo: 0.1 to 4.0%
Al: 0.35 to 3.0%
Ti: 0.01 to 0.20%
N: not more than 0.05%
O: 0.004% or less, the balance being Fe and unavoidable impurities,
Wherein an Md30 value represented by the following formula (a) is -10 to 70, an Ng value defined by the following formula (b) is N or more and 0.10 or less, and a tensile strength is 2000 N / Curable metastable austenitic stainless steel wire.
Md30 = 551-462 (C + N) -9.2Si-8.1 Mn-29 (Ni + Cu) -13.7Cr-18.5Mo (a)
Ng = 0.002 / (Al x Ti) (b) The precipitation hardening type metastable austenitic stainless steel wire according to claim 1, wherein the martensite content is not less than 25% by volume and less than 85% by volume. A quasi-stable austenitic stainless steel according to any one of claims 1 to 3, further comprising, in% by mass, at least one group selected from the following group A to E: Steel wire.
(A) 0.05 to 2.0% of V, 0.05 to 2.0% of Nb, 0.05 to 2.0% of W, 0.05 to 2.0% of Ta,
(B) 0.1 to 4.0% of Co,
(C) Cu: 0.1 or more, less than 2.0%
(D) B: 0.0005 to 0.015%
(E) at least one of 0.0005 to 0.01% of Ca, 0.0005 to 0.01% of Mg, and 0.0005 to 0.05% of REM. A production method of a precipitation hardening metastable austenitic stainless steel wire excellent in fatigue resistance, characterized in that an aging treatment is carried out at 300 to 600 ° C after cold working, as a manufacturing method of the stainless steel wire according to any one of claims 1 to 4. A method for producing a stainless steel wire according to claim 3, characterized by subjecting the steel wire to an aging treatment at 300 to 600 ° C after cold working, thereby producing a precipitation hardening type metastable austenitic stainless steel wire having excellent fatigue resistance. 5. The method according to claim 4, wherein the aging treatment is carried out in a nitrogen atmosphere. 6. The method according to claim 5, wherein the aging treatment is performed in a nitrogen atmosphere. A spring comprising a precipitation hardening type metastable austenitic stainless steel wire excellent in fatigue resistance according to any one of claims 1 to 3. Resistant stainless steel wire having excellent fatigue resistance according to claim 3. delete

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