WO2012160594A1 - Austenitic stainless steel for spring, and stainless processing material for spring - Google Patents

Abstract

Provided are an inexpensive low Ni-type austenitic stainless steel for a spring and a stainless processing material for a spring, the stainless steel and stainless processing material exhibiting the same mechanical properties as SUS301 which is a conventional steel and being able to maintain the properties exhibited by non-magnetic bodies by inhibiting the magnetic permeability from rising even when imparted with high strength as a consequence of being subjected to cold working. In other words, the present invention contains, in mass %, 0.12% or less C, 1.0% or less Si, 7.0 to 9.0% Mn, 1.0 to 2.0% Ni, 16.0 to 18.0% Cr, 2.0% or less Mo, 2.3% or less Cu, 0.10% or less Nb, and 0.10 to 0.20% N, the remainder being Fe and unavoidable impurities, wherein the Md₃₀Mn value is between -50 and -30 when calculated using the following equation: Md₃₀Mn=551-462([%C]+[%N])-9.2[%Si]-19.1[%Mn]-13.7[%Cr]-29([%Ni]+[%Cu])-18.5[%Mo]-68[%Nb].

Description

Austenitic stainless steel for spring and stainless steel processed material for spring

TECHNICAL FIELD The present invention relates to a low Ni austenitic stainless steel for springs that is excellent in mechanical strength and is used for home appliances, automobile parts, and the like, and a stainless steel material for springs that has been further strengthened by cold working. .

SUS301 and SUS304, which are standardized in JIS G 4313, are known as typical spring stainless steels. SUS301 and SUS304 are work-hardening type metastable austenitic stainless steels that can obtain high strength by cold working.

These work-hardening type metastable austenitic stainless steels have an austenitic structure in a solution-treated state, and after being solution-treated, they are subjected to cold working such as cold rolling. A site (α ^' ) is generated and the strength is increased. It is known that the strength depends on the amount of cold working that the metastable austenitic stainless steel receives and the amount of work-induced martensite (α ^′ ) produced.

As described above, SUS301 and SUS304 listed here are cold-worked to produce work-induced martensite (α ^′ ), which increases the mechanical strength of the steel. It becomes high, and what is a non-magnetic material in the solution treatment state becomes difficult to be a non-magnetic material after cold working. In addition, the work-hardening type metastable austenitic stainless steel whose magnetic permeability has been increased and has become difficult to be said to be a non-magnetic material cannot be used for applications that dislike the influence of magnetism, such as springs for electronic parts. There was a problem.

Therefore, as a technique for suppressing the increase in magnetic permeability after such cold working and obtaining a work-hardening type metastable austenitic stainless steel that can be used as a nonmagnetic spring, 0.05 ≦ C ≦ 0 in mass%. .10%, Si ≦ 1.0%, 5.0 ≦ Mn <6.0%, P ≦ 0.10%, S ≦ 0.010%, 2.5 ≦ Ni ≦ 3.0%, 17.0 ≦ Cr ≦ 18.0%, 0.10 ≦ Mo ≦ 0.30%, 2.5 ≦ Cu ≦ 2.8%, 0.15 ≦ N ≦ 0.18%, the balance being Fe and inevitable An austenitic stainless steel for springs characterized by having a chemical composition consisting of mechanical impurities has been proposed (see, for example, Patent Document 1).

According to this technology, it is possible to provide a non-magnetic austenitic stainless steel for a spring even when subjected to cold working.

Japanese Patent No. 4333131

By the way, the non-magnetic austenitic stainless steel for spring contains 2.5% by mass or more and 3.0% by mass or less of Ni. This Ni is an expensive and valuable material (element). is there. For this reason, in order to provide a cheaper non-magnetic austenitic stainless steel for springs at the same time as enabling continuous use (resource protection) of the metal resource, the Ni content in the stainless steel is further reduced. Is required.

Therefore, the main problem of the present invention is that, in addition to having mechanical properties equivalent to SUS301, which is mainly a conventional steel, even if high strength is imparted by cold working, the increase in permeability is suppressed. Low-cost Ni-type “austenitic stainless steel for springs” capable of maintaining properties as a magnetic material, and non-magnetic “stainless steel for springs” formed by cold working such stainless steel ".

The inventors have intensively studied to solve the above problems, and as a result, have completed the invention shown below. That is, the first invention in the present invention is:
(1) By mass%, C ≦ 0.12%, Si ≦ 1.0%, 7.0% ≦ Mn ≦ 9.0%, 1.0% ≦ Ni ≦ 2.0%, 16.0% ≦ Containing Cr ≦ 18.0%, Mo ≦ 2.0%, Cu ≦ 2.3%, Nb ≦ 0.10%, 0.10% ≦ N ≦ 0.20%, the balance being Fe and inevitable impurities Become
(2) Md ₃₀ Mn = 551-462 ([% C] + [% N]) − 9.2 [% Si] −19.1 [% Mn] −13.7 [% Cr] −29 ([% Ni] + [% Cu])-18.5 [% Mo] -68 [% Nb] Md ₃₀ Mn value satisfying −50 ≦ Md ₃₀ Mn ≦ −30 (3) For austenitic stainless steel ".

Further, a second invention in the present invention is a “stainless steel material for spring”, characterized in that the austenitic stainless steel for spring according to the first invention is cold worked.

Here, “stainless steel material for springs” includes automobile parts such as automobile gaskets, automobile brake shims, automobile brake pad clips, seat belt retractors, electrical equipment connectors, electronic parts springs, etc. -Electronic parts, building hardware such as building material springs and architectural fasteners, stationery hardware such as pen clips, and toy parts such as toy springs and toy springs.

According to the present invention, since the blending ratio of expensive Ni is suppressed within the range of 1.0% by mass to 2.0% by mass, a predetermined austenitic stainless steel for spring can be economically manufactured. .

Md ₃₀ Mn = 551-462 ([% C] + [% N]) − 9.2 [% Si] −19.1 [% Mn] −13.7 [% Cr] −29 ([% Ni ] + [% Cu])-18.5 [% Mo] -68 [% Nb] The Md ₃₀ Mn value is in the range of −50 ≦ Md ₃₀ Mn ≦ −30. It can prevent cracking and improve manufacturability, and suppress the formation of work-induced martensite (α ^' ) during cold working to suppress the increase in magnetic permeability, which makes steel non-magnetic (strictly speaking, Weak magnetism) can be secured.

Therefore, in addition to having mechanical properties equivalent to SUS301, which is mainly a conventional steel, even if high strength is imparted by cold working, the magnetic permeability is suppressed and the properties as a non-magnetic material are maintained. Ni-saving inexpensive “Austenitic stainless steel for springs” and high strength and non-magnetic “stainless steel for springs” formed by cold working such stainless steel can do.

It is a graph which shows the relationship between the rolling reduction and tensile strength of each temper rolled sheet. It is a graph which shows the relationship between the rolling reduction of each temper rolled sheet, and 0.2% yield strength. It is a graph which shows the relationship between the rolling reduction and elongation of each temper rolled sheet. It is a graph which shows the relationship between the rolling reduction and hardness of each temper rolled sheet. It is a graph which shows the relationship between the hardness of each temper rolled sheet, and a relative magnetic permeability. It is a graph which shows the relationship between the rolling reduction of each temper rolled sheet, and a work induction martensitic transformation phase amount. It is a drawing substitute photograph which shows the result of a dip and dry test.

First, the reasons for limitation of each component constituting the “spring austenitic stainless steel” (hereinafter simply referred to as “steel”) according to the present invention will be described.

1) C ≦ 0.12% by mass: C (carbon) is an extremely effective element for strengthening the martensite phase, and has the effect of generating precipitates and increasing the spring limit value. Further, C, as an austenite forming element, reduces δ ferrite formed at the time of solidification and in a high temperature region, and suppresses a decrease in hot workability. However, excessive addition of C increases the susceptibility to intergranular corrosion by causing chromium carbide to precipitate at the grain boundaries in the heat-affected zone and the hot-rolled coil after coiling. Make it easy to do. Therefore, the C content of the steel needs to be 0.12% by mass or less (more preferably 0.10% by mass or less).

Note that the lower limit of the C content is not particularly limited, but the C content is preferably 0.07% by mass or more in order to exert the C-containing effect remarkably.

2) Si ≦ 1.0% by mass: Si (silicon) is an element that exhibits an effect as a deoxidizer during steelmaking. Further, since Si has an effect of lowering stacking fault energy, it promotes the generation of ε martensite phase by rolling. However, the subsequent processing during product molding not only promotes the formation of the α ^′ martensite phase, but when this Si is contained in a large amount, a large amount of δ ferrite is generated at the time of solidification and in a high temperature range. That is, since it is disadvantageous for obtaining an austenite structure, the upper limit of the Si content of the steel is set to 1.0 mass% (more preferably 0.6 mass% or less).

Note that the lower limit of the Si content is not particularly limited, but the Si content is preferably 0.4% by mass or more in order to exert the Si-containing effect remarkably.

3) 7.0% by mass ≦ Mn ≦ 9.0% by mass: Mn (manganese) is an element that can replace Ni as an austenite forming element, and by increasing the Mn content as much as possible, Since the usage rate of expensive Ni can be reduced, it is effective in reducing the product cost of steel. Moreover, since Mn has the effect | action which reduces a stacking fault energy, generation | occurrence | production of the epsilon martensite phase by rolling is accelerated | stimulated. In addition, in order to acquire this effect, Mn content of 7.0 mass% or more (more preferably 7.5 mass% or more) is required. On the other hand, excessive addition of Mn reduces the corrosion resistance of the steel, so the upper limit of its content was 9.0% by mass (more preferably 8.5% by mass or less).

4) 1.0 mass% ≦ Ni ≦ 2.0 mass%: Ni (nickel) is an austenite forming element. Ni is an essential element in the steel according to the present invention in order to obtain the stability of the austenite structure, the good hot workability of the steel, and the good cold workability of the steel. However, as described above, Ni is an expensive and valuable element, and also causes metal allergy, so the upper limit of the Ni content is 2.0% by mass (more preferably 1.5% by mass). The lower limit was made 1.0 mass%.

5) 16.0% by mass ≦ Cr ≦ 18.0% by mass: Cr (chromium) is one of the most effective elements for enhancing the corrosion resistance of steel, and 16.0 mass for obtaining sufficient corrosion resistance. % Cr content is required. However, if the Cr content exceeds 18.0% by mass, a lot of δ ferrite is generated at the time of solidification and in a high temperature range, so that the hot workability of the steel is lowered. Therefore, the upper limit of the Cr content is 18.0% by mass (more preferably 17.0% by mass or less).

6) Mo ≦ 2.0% by mass: Mo (molybdenum) is an element capable of improving the corrosion resistance of steel. However, the content of Mo exceeding 2.0% by mass is a large amount during solidification and in a high temperature range. There is a possibility that δ ferrite is generated and the hot workability of the steel is lowered. Therefore, the upper limit of the Mo content is set to 2.0% by mass. In order to more effectively suppress such harmful effects, the Mo content is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less.

7) Cu ≦ 2.3 mass%: Cu (copper) is an austenite forming element and is effective as an alternative element for Ni. In addition, this Cu is an element that enhances the corrosion resistance of steel and contributes to ensuring non-magnetism even after cold working. However, when the Cu content exceeds 2.8 mass%, hot workability is improved. If the amount exceeds 2.3% by mass, softening of the steel becomes significant when the steel is treated, so the upper limit of the Cu content is 2.3% by mass.

Note that the lower limit of the Cu content is not particularly limited, but the Cu content is preferably 1.5% by mass or more in order to exert the above Cu-containing effect remarkably.

8) Nb ≦ 0.10% by mass: Nb (niobium) is an element effective for increasing the strength of the steel and suppresses the precipitation of Cr carbide at the grain boundaries by forming NbC. It is an element that has the effect of increasing the intergranular corrosion sensitivity. However, if Nb content exceeds 0.10% by mass, a large amount of δ ferrite is generated during solidification and in a high temperature range, which may reduce the hot workability of the steel. Therefore, the upper limit of the Nb content is set to 0.10% by mass. In order to more effectively suppress such harmful effects, the Nb content is preferably 0.05% by mass or less.

9) 0.10% by mass ≦ N ≦ 0.20% by mass: N (nitrogen) is an austenite-forming element like C. N is an element effective for stabilizing the austenite structure, strengthening the metal structure, and improving the corrosion resistance of the steel. And in order to acquire these effects, N content is 0.10 mass% or more, but 0.12 mass% or more is preferable from a viewpoint of austenite reinforcement | strengthening. However, since N has a large solid solution strengthening ability, the addition of N exceeding 0.20% by mass brings about significant hardening of the steel. Therefore, the upper limit of the N content is 0.20% by mass, and the lower limit is 0.10% by mass.

10) −50 ≦ Md ₃₀ Mn ≦ −30: The Md ₃₀ Mn value is an index representing the ease of processing-induced martensite (α ^′ ) transformation that occurs when austenitic stainless steel is processed, and Md ₃₀ Mn = 551-462 ([% C] + [% N])-9.2 [% Si] -19.1 [% Mn] -13.7 [% Cr] -29 ([% Ni] + [% Cu] ) -18.5 [% Mo] -68 [% Nb]. The larger this value, the easier the processing-induced martensite (α ^′ ) transformation occurs. That is, if the Md ₃₀ Mn value is large, a large amount of work-induced martensite (α ^′ ) phase is generated during rolling, and the workability of the temper rolled sheet is lowered.

On the other hand, when the Md ₃₀ Mn value is small, the work-induced martensite (α ^′ ) phase generated during the shaping of the temper rolled sheet decreases (probably ε-martensite is generated during rolling). An increase in magnetic permeability can be suppressed. For this reason, in order to suppress the formation of work-induced martensite (α ^′ ) during cold working to suppress the increase in magnetic permeability and to ensure the non-magnetism (strictly weak magnetism) of steel, Md ₃₀ It is preferable that Mn ≦ −30. However, when Md ₃₀ Mn is less than −50, the desired hardness cannot be obtained by cold working, and the formability of the temper rolled material may be lowered. Therefore, the lower limit is preferably −50 (Md ₃₀ Mn ≧ −50).

Note that “%” in the above formula means “mass%”, and “% element symbol” means “the content ratio of elements in steel expressed in mass%”.

Furthermore, in addition to the above elements and parameters, it is more preferable to adjust the content of the following elements.

11) P ≦ 0.060 mass%: P (phosphorus) is an element that causes deterioration of the corrosion resistance and hot workability of steel, so the upper limit of its content was set to 0.060 mass%. Note that this P may be regarded as an inevitable impurity.

12) S ≦ 0.003 mass%: S (sulfur) is an element that increases inclusions and decreases the resistance to galling of steel. Moreover, since the increase in S content remarkably reduces hot workability, the upper limit of S content was set to 0.003 mass%. The S may be regarded as an inevitable impurity.

The steel according to the present invention composed of the elements as described above is manufactured by a general stainless steel manufacturing process. That is, solution heat treatment is performed after melting, casting, hot rolling and cold rolling. And in order to acquire the characteristic requested | required as a raw material of a spring, it cold-processes (temper rolling) and is tempered to desired hardness.

Further, the “stainless steel material for spring” of the present invention is the cold-drawn steel using the temper rolling (then formed into a predetermined shape by punching, etc.) or a die obtained as described above. It is obtained by performing cold working such as machining. Specific applications of the “stainless steel material for springs” made of the steel of the present invention having the same mechanical properties as the conventional steel SUS301 include automotive gaskets, automotive brake shims, and automotive brake pads. Auto parts such as clips and seat belt retractors, electrical and electronic parts such as electrical equipment connectors, springs for electronic parts, construction hardware such as building material springs and construction fasteners, stationery hardware such as pen clips, and toys And toy parts such as springs for toys and mainspring springs for toys. In addition to being able to achieve cost reductions due to low Ni in all applications, in applications where there is a possibility of human touch such as connectors for electrical equipment, stationery fittings, toy parts, etc., suppress the possibility of inducing metal allergy with low Ni You can also. In particular, the “stainless steel material for springs” made by cold working the steel of the present invention, which can ensure the non-magnetism of the steel after cold working, should be used more favorably in electrical and electronic parts that do not like the influence of magnetism. Can do.

Hereinafter, as an example according to the present invention, a method for producing a steel sample, a test method, and results will be described. In addition, this invention is not limited to the said Example.

1) Time cracking susceptibility, confirmation of presence or absence of ferrite structure and evaluation of work hardening characteristics In order to obtain a steel having a chemical composition as shown in Table 1, an ingot of 38 mm × 90 mm × 150 mm was manufactured in a high-frequency melting furnace. The ingot was heated in an electric furnace at 1200 ° C. for 60 minutes and hot-rolled to a thickness of 3.0 mm with a four-high rolling mill to obtain a hot-rolled sheet. The conventional steel 1 in Table 1 is commercially available SUS301 standardized by JIS G 4313.

Subsequently, this hot-rolled sheet was annealed at 1100 ° C. for 6 minutes, immersed in nitrohydrofluoric acid to remove the scale, and then cold-rolled to 1.0 mm with a four-high rolling mill, and further at 1100 ° C. for 2 minutes. It was annealed and dipped in nitric hydrofluoric acid to remove the scale, and a cold-rolled annealed pickled plate was obtained. Using the obtained cold-rolled annealed pickling plate as a raw material, cold-rolled tempered rolled plates with a rolling reduction of 30% and 50% were prepared and subjected to the following property evaluation tests.

(1) Sensitivity to time cracking A round test piece (φ85mm) was taken from the cold-rolled annealed pickling plate of 1.0mm thickness produced in the above process, and the test piece was drawn into a cup shape with a drawing ratio of 1.70. A molding test was conducted (drawing test conditions: punch diameter: φ50 mm, die diameter: φ53 mm, drawing speed: 25 mm / min, wrinkle holding pressure 23.5 kN, test temperature: 25 ° C., number of tests: n = 3). And the lubricating oil was apply | coated to the test piece after a drawing process, and it hold | maintained for 500 hours in 40 degreeC environment, and the presence or absence and generation | occurrence | production number of the time crack were confirmed. As a result of such a test, “no crack occurrence” is indicated by ○, and “crack occurrence” is indicated by ×.

(2) Confirmation of presence or absence of ferrite structure A sample is cut out from the cold-rolled annealed pickling plate having a thickness of 1.0 mm manufactured in the above process, the cross section is embedded in a resin, buffed, and then subjected to electrolytic etching in a nitric acid solution. It was. Then, the structure was observed with an optical microscope, and the presence or absence of the ferrite structure was confirmed. As a result of such observation, “no residual ferrite structure” is indicated by ○, and “with residual ferrite structure” is indicated by ×. If the ferrite structure remains on the cold-rolled annealed sheet, it becomes magnetized before temper rolling, so it cannot satisfy the non-magnetic requirement that is the development objective of this steel.

(3) Work hardening characteristics A sample was cut out from each tempered rolled plate produced at a rolling reduction of 30% and 50%, a Vickers hardness test was performed, and the work hardening characteristics were evaluated.
-Hardness of 30% temper rolled sheet: “HV370 or higher” is indicated by ○, and “less than HV370” is indicated by ×.
-Hardness of 50% tempered rolled sheet: “HV430 or higher” is indicated by ○, and “less than HV430” is indicated by ×.

Here, “HV370 or higher” and “HV430 or higher” indicate the hardness standards in JIS G 4313 SUS301-CSP tempered symbols 3 / 4H and H, respectively. If the hardness corresponding to 3 / 4H at a rolling reduction of 30% and H at 50% cannot be obtained, it cannot be said that the steel has work hardening characteristics similar to SUS301. Even if the desired hardness can be obtained by a reduction ratio higher than that, the productivity of cold rolling will be hindered, leading to an increase in manufacturing cost. Absent.

Table 2 shows the evaluation results of the time cracking susceptibility, the presence or absence of the ferrite structure, and work hardening characteristics in each test piece.

As is apparent from Table 2 above, it can be seen that Invention Steels 1 to 6 are all good in time cracking susceptibility, the presence or absence of ferrite structure, and work hardening characteristics.

On the other hand, in comparative steels 1 to 3 and 7 to 9 having an Md ₃₀ Mn value larger than −30, it is apparent that there is a problem in manufacturability because time cracking occurs after drawing. Further, in comparative steels 4 to 6 having a Md ₃₀ Mn value smaller than −50, there is no problem of time cracking, but the ferrite structure remains, and it seems that the nonmagnetic property of the steel cannot be satisfied.

What should be noted here is that the comparative steel 7 having an Md ₃₀ Mn value larger than −30, although the content of each element is within the range of the present invention, has a time crack after drawing. Is a point. Thus, in spite of the fact that the content of each element is within the scope of the present invention, there is a problem in manufacturability such as time cracking (the content of each element is equal to or higher than the content). Md ₃₀ Mn is presumed to be a very important parameter representing the properties of steel.

Further, in Comparative Steels 10 to 14 in which the Md ₃₀ Mn value is smaller than −50 and the Ni content exceeds the upper limit of the present invention, the non-magnetic requirement is satisfied, but the processing by cold working is satisfied. It can be seen that the hardening characteristics are inferior to SUS301, which is an existing steel, and sufficient work hardening by temper rolling cannot be obtained.

2) Comparison of characteristics between the steel of the present invention and SUS301 Within the range of elemental composition of the austenitic stainless steel for springs of the present invention, that is, by mass%, C ≦ 0.12%, Si ≦ 1.0%, 7.0% ≦ Mn ≦ 9.0%, 1.0% ≦ Ni ≦ 2.0%, 16.0% ≦ Cr ≦ 18.0%, Mo ≦ 2.0%, Cu ≦ 2.3%, Nb ≦ 0. A steel containing 10%, 0.10% ≦ N ≦ 0.20%, the balance being Fe and inevitable impurities, and satisfying −50 ≦ Md ₃₀ Mn ≦ −30 was produced on an actual machine line. Each element is melted and mixed in a 70-ton electric furnace, and after a refining and continuous casting process, an austenitic stainless steel slab for a spring of the present invention is manufactured, and this is heated to a thickness of 3.0 mm with a four-stage rolling mill. Hot rolling was obtained by hot rolling.

The chemical component analysis results of the actual machine manufactured steel (invention steel) are shown in Table 3 together with the component analysis results of commercially available SUS301 (hereinafter also referred to as “conventional steel”) for comparison.

Subsequently, the hot-rolled sheet was subjected to annealing pickling in a continuous annealing pickling line, and then rolled to 1.0 mm with a cold rolling mill. Further, this cold-rolled sheet was subjected to annealing pickling in a continuous annealing pickling line, and then subjected to temper rolling at 10 to 70% in a cold rolling mill.

And the JIS13B test piece was extract | collected from each tempered rolling board from which produced board thickness differs, and the tensile test and the Vickers hardness measurement were performed based on JISZ2241 about the said test piece and SUS301 of a conventional steel as a comparison. . The results of the test are shown in FIGS.

In addition, the magnetic permeability of each test piece having a different rolling reduction was measured, and the amount of work-induced martensitic transformation phase was measured with a ferrite scope. The measurement results are shown in FIGS.

Furthermore, in order to evaluate the corrosion resistance, a dip-and-dry test was performed. The test solution composition and test conditions used in the dip and dry test are shown in Table 4 and Table 5, respectively, and the obtained results are shown in FIG.

 

 

As shown in FIGS. 1 to 4, it can be seen that the stainless steel of the present invention has almost the same mechanical characteristics as conventional SUS301.

Further, as shown in FIG. 5 and FIG. 6, the stainless steel of the present invention is different from the conventional SUS301 in that the formation of work-induced martensite (α ^′ ) during cold working is suppressed, and as a result, It can be seen that the increase in magnetic permeability is suppressed, and the non-magnetic property (strictly weak magnetism) of the steel is secured.

Furthermore, as shown in FIG. 7, it can be seen that the stainless steel of the present invention has a corrosion resistance equivalent to or slightly superior to that of conventional SUS301.

As described above, according to the “spring austenitic stainless steel” of the present invention, in addition to having mechanical properties equivalent to SUS301, which is a conventional steel, even if high strength is imparted by cold working, It is possible to provide an inexpensive Ni-saving “austenitic stainless steel for springs” that can suppress the increase in magnetic susceptibility and maintain the properties as a non-magnetic material.

Claims (3)

% By mass, C ≦ 0.12%, Si ≦ 1.0%, 7.0% ≦ Mn ≦ 9.0%, 1.0% ≦ Ni ≦ 2.0%, 16.0% ≦ Cr ≦ 18 0.0%, Mo ≦ 2.0%, Cu ≦ 2.3%, Nb ≦ 0.10%, 0.10% ≦ N ≦ 0.20%, with the balance being Fe and inevitable impurities,
Md ₃₀ Mn = 551-462 ([% C] + [% N]) − 9.2 [% Si] −19.1 [% Mn] −13.7 [% Cr] −29 ([% Ni] + Austenitic stainless steel for springs, characterized in that the Md ₃₀ Mn value according to [% Cu])-18.5 [% Mo] -68 [% Nb] satisfies −50 ≦ Md ₃₀ Mn ≦ −30. A spring processed stainless steel material, wherein the spring austenitic stainless steel according to claim 1 is cold worked. Stainless steel processed material for spring is automotive gasket, automotive brake shim, automotive brake pad clip, seat belt retractor, electrical equipment connector, electronic component spring, building material spring, architectural fastener, pen clip, toy The stainless steel processed material for spring according to claim 2, which is at least one selected from the group consisting of a spring for toys and a mainspring spring for toys.

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