JP2022505375A - A method for manufacturing a high manganese steel material having excellent vibration isolation and formability, and a high manganese steel material manufactured by this manufacturing method. - Google Patents

Abstract

The present invention relates to a steel material used for automobiles, building steel sheets, etc., and more specifically, vibration-proofing property and formability that can be used in places where vibration-proofing property for noise reduction is required. It relates to an excellent high manganese steel material and a method for producing the same.

Description

The present invention relates to steel materials used for steel sheets for automobiles or construction, and more specifically, vibration-proofing and molding that can be used in places where vibration-proofing for noise reduction is required. The present invention relates to a highly manganese steel material having excellent properties and a method for producing the same.

Recently, noise reduction is a problem that manufacturers must solve in materials such as automobile manufacturing or building materials. In the case of automobile manufacturers, components such as engine parts and oil pans, which generate a large amount of noise, are particularly required to have excellent mechanical properties and vibration isolation. In the case of building materials, as regulations on floor noise are tightened, it is actually required to develop steel materials with excellent vibration isolation as bottom plates of multi-story buildings including apartments.

On the other hand, high manganese (Mn) anti-vibration steel is a steel grade having high anti-vibration properties and excellent mechanical properties by converting noise energy into thermal energy by interfacial sliding of epsilon martensite at the time of external impact. Suitable for use for the purpose of noise reduction.

In general, high manganese anti-vibration steel is obtained by producing a hot-rolled or cold-rolled steel sheet by a series of steelmaking-continuous casting-hot-rolling steps or by adding a cold-rolling step to the series, and then post-heat-treating the steel sheet. Is applied to form epsilon martensite and / or a recrystallized structure to ensure anti-vibration properties.

By the way, the post-heat treatment step performed for ensuring vibration isolation is a high-cost heat treatment usually applied at a temperature of 900 ° C. or higher for a time of more than 10 minutes, preferably 60 minutes or longer. This is a factor that hinders the generalization of manganese anti-vibration steel.

Currently, the demand for noise reduction is continuously increasing, and it is necessary to develop a steel material that can achieve both vibration isolation and excellent formability while omitting post-heat treatment, which is a high-cost heat treatment. Is the actual situation.

Korean Registered Patent No. 10-1736636

One aspect of the present invention is that in providing high manganese anti-vibration steel, the post-heat treatment step which is indispensable for improving the anti-vibration property can be omitted, and the post-heat treatment step can be omitted, and the cost is lower than the conventional one. It is a method of producing a high manganese steel material having excellent vibration property and formability, and providing a high manganese steel material produced by this method.

The subject of the present invention is not limited to the above-mentioned contents. Further problems of the present invention are described in the general contents of the specification, and if the person has ordinary knowledge in the technical field to which the present invention belongs, the contents described in the specification of the present invention can be used. There is no difficulty in understanding the further subject of the present invention.

One aspect of the present invention is carbon (C): 0.1% or less, manganese (Mn): 8 to 30%, silicon (Si): 3.0% or less, phosphorus (P): 0. 1% or less, sulfur (S): 0.02% or less, nitrogen (N): 0.1% or less, titanium (Ti): 1.0% or less (excluding 0%), boron (B): 0. A step of heating a steel slab containing 01% or less of the balance Fe and other unavoidable impurities at a temperature of 1150 to 1350 ° C.; a step of finishing and hot rolling the heated steel slab to produce a hot-rolled steel sheet; and the above. The finish hot rolling is performed at a temperature (FDT (° C.)) satisfying the following relational expression 1, including a step of cooling the hot-rolled steel sheet to 700 ° C. or lower, and is excellent in vibration isolation and formability. Provided is a method for producing a high manganese steel material.

[Relational expression 1]
FDT (° C.) ≧ 928 + (480 × C) + (450 × N) + (0.9 × Mn) + (65 × Ti)
(Here, each element means weight content.)

Another aspect of the present invention is a steel material produced by the above-mentioned production method, which has the above-mentioned alloy composition and contains epsilon martensite having an area fraction of 90% or more and a residual austenite phase as a microstructure. Provided is a high manganese steel material having a completely recrystallized structure and excellent anti-vibration property and formability.

According to the present invention, it is possible to provide a high manganese steel material having excellent vibration-proofing property and formability even if the post-heat treatment step conventionally required for improving the vibration-proofing property of manganese vibration-proof steel is omitted. ..

Further, the present invention can provide high manganese anti-vibration steel at a relatively low cost by omitting the post-heat treatment step, and therefore has technical effects in terms of economy, and anti-vibration properties are required. There is an effect that it can be applied universally in the field to be used.

In one embodiment of the present invention, it is a graph which showed the value of the loss rate at the deformation rate of 900 (m / (m × ^10-6 )) of the invention steel and the comparative steel according to FDT (° C.). It is a graph which showed the value of the loss rate at the deformation rate of 200 to 900 (m / (m × ^10-6 )) of the invention steel and the comparative steel in one Example of this invention. It shows the microstructure photograph of the invention steel by one Example of this invention. It shows the XRD measurement result of the invention steel and the comparative steel by one Example of this invention. The method of measuring the loss rate with respect to the deformation rate by the cantilever method is illustrated.

In the case of conventional high manganese vibration-proof steel, the present inventors need to apply a high-cost heat treatment (also known as a post-heat treatment step) in order to improve the vibration-proof property, which ultimately reduces the manufacturing cost. It was confirmed that there is a limit to generalization as well as a significant increase.

Therefore, the present inventors have diligently studied a method capable of achieving both vibration isolation and excellent moldability without omitting high-cost heat treatment. As a result, by optimizing the manufacturing process as well as controlling the alloy composition, the fraction of the epsilon martensite phase in the steel can be maximized, which results in vibration isolation and formability even in a series of hot rolling processes alone. It was confirmed that excellent steel materials could be provided, and the present invention was completed.

Hereinafter, the present invention will be described in detail.

The method for producing a high manganese steel material having excellent vibration isolation and formability according to one aspect of the present invention is to prepare a steel slab having an alloy composition described later, and then hot-roll and cool the steel slab to obtain a high manganese steel material. Can be manufactured.

First, the reason for limiting the alloy composition in obtaining the high manganese steel material intended in the present invention will be described in detail. At this time, unless otherwise specified, the content of each element means the weight content (% by weight).

Carbon (C): 0.1% or less Carbon (C) is an element that stabilizes austenite in steel and is advantageous for ensuring strength. However, if the content exceeds 0.1%, the fraction of dissolved C becomes excessively high, which may hinder hot workability and significantly reduce anti-vibration properties.
Therefore, in the present invention, C can be contained in an amount of 0.1% or less, and even if the content is 0%, it is not unreasonable to secure the target physical properties.

Manganese (Mn): 8-30%
Manganese (Mn) is an essential element for stably securing austenite and epsilon martensite structure. The present invention needs to contain 8% or more of the above Mn in order to secure the epsilon martensite phase in a certain fraction or more without performing a separate heat treatment step. However, if the content exceeds 30%, the production cost increases, and the phosphorus (P) content increases in the process of refining a large amount of Mn, which causes slab cracking. Further, as the Mn content increases, there is a problem that internal grain boundary oxidation is excessively generated during slab heating to induce oxide defects on the steel surface, and the surface characteristics are also deteriorated during subsequent plating.
Therefore, in the present invention, Mn can be contained in an amount of 8 to 30%, and more preferably 14 to 20%.

Silicon (Si): 3.0% or less Silicon (Si) is an element that is strengthened by solid solution, and is advantageous for reducing the crystal grain size and improving the yield strength by the solid solution effect. By the way, when the content of such Si increases, a silicon compound is formed on the surface of the steel sheet during hot rolling, the pickling property deteriorates, and the surface quality of the hot-rolled steel sheet deteriorates. Further, if it is added excessively, the weldability is greatly deteriorated.
Therefore, in the present invention, Si can be contained in an amount of 3.0% or less, and even if the content is 0%, it is not unreasonable to secure the target physical properties.

Phosphorus (P): 0.1% or less and sulfur (S): 0.02% or less Phosphorus (P) and sulfur (S) are elements that are inevitably contained in the production of steel and are contained as much as possible. The lower the amount, the better. Of these, if the content of P exceeds 0.1%, segregation is caused and the workability of the steel is reduced, and if the content of S exceeds 0.02%, coarse manganese sulfide (coarse manganese sulfide) ( There is a problem that MnS) is formed to cause defects such as flange cracks, which hinders the formability of the steel sheet, particularly the hole expandability.
Therefore, in the present invention, P can be contained in an amount of 0.1% or less and S can be contained in an amount of 0.02% or less.

Nitrogen (N): 0.1% or less Nitrogen (N) is an element that forms a nitride, and when its content exceeds 0.1%, the fraction of dissolved N becomes excessively high and it is hot. It inhibits workability and elongation and reduces vibration isolation.
Therefore, in the present invention, even if N is contained in an amount of 0.1% or less and the content is 0%, it is not unreasonable to secure the target physical properties.

Titanium (Ti): 1.0% or less (excluding 0%)
Titanium (Ti) is an element that combines with carbon to form carbides, and the formed carbides suppress the growth of crystal grains and are advantageous for finer grain size. In addition, it forms a compound with C and N and has a scavenging effect, which is advantageous for improving anti-vibration properties. When the Ti content exceeds 1.0%, an excessive amount of titanium segregates at the grain boundaries and causes grain boundary embrittlement, or the formation of a coarse precipitated phase inhibits the effect of suppressing crystal grain growth. There are times.
Therefore, in the present invention, Ti can be contained in an amount of 1.0% or less, but 0% is excluded.

Boron (B): 0.01% or less Boron (B) has the effect of forming a high-temperature compound at the grain boundaries and preventing grain boundary cracks when added together with Ti. By the way, if the content of such B exceeds 0.01%, it is not preferable because it forms a boron compound and deteriorates the surface characteristics.
Therefore, in the present invention, B can be contained in an amount of 0.01% or less, and even if the content is 0%, it is not unreasonable to secure the target physical properties.

When the steel material of the present invention contains each element in the above composition, when C and N are added in combination, the sum (C + N, weight%) of these contents is preferably 0.1% or less.

The above C and N are penetrating solid solution elements, and when they are combined with Ti or the like to form a carbonitride, the anti-vibration performance can be improved, but the sum of these contents is 0. If it exceeds 1%, the fraction of dissolved C or dissolved N becomes high, the hot workability and elongation are lowered, and the vibration isolation property is lowered, which is not preferable.
Therefore, at the time of the combined addition of C and N, the sum of the contents can be 0.1% or less.

On the other hand, the steel material of the present invention may further contain additional elements in addition to the above-mentioned alloy composition in order to improve the physical properties.

As one aspect, one or more of nickel (Ni): 0.005 to 2.0% and chromium (Cr): 0.005 to 5.0% can be further contained.

Nickel (Ni): 0.005 to 2.0%
Nickel (Ni) is an element that effectively contributes to ensuring high temperature ductility. In order to obtain the above-mentioned effect, it can be contained in an amount of 0.005% or more, and as the content increases, it is also effective in preventing delayed fracture and slab cracking. However, the above Ni is an expensive element, and in consideration of this, it can be contained in an amount of 2.0% or less.

Chromium (Cr): 0.005 to 5.0%
Chromium (Cr) reacts with external oxygen during hot rolling or annealing steps to preferentially form a Cr-based oxide film (Cr ₂ O ₃ ) on the surface of steel with a thickness of 20 to 50 μm. Prevents Mn, Si, etc. contained in the steel from elution on the surface layer. This contributes to the stabilization of the steel surface structure and has the effect of improving the surface characteristics of the plating. In order to obtain the above-mentioned effects, Cr can be contained in an amount of 0.005% or more, but if the content exceeds 5.0%, chromium carbide is formed, and on the contrary, processability and delayed fracture resistance are deteriorated. It is not preferable because it decreases.
Therefore, in the present invention, when Cr is added, it can be contained in an amount of 0.005 to 5.0%.

Further, as one aspect, niobium (Nb): 0.005 to 0.5%, vanadium (V): 0.005 to 0.5%, and tungsten (W): 0.005 to 1.0%. One or more may be further included.

Niobium (Nb): 0.005-0.5%
Niobium (Nb) is an element that combines with carbon in steel to form carbides, and can have the effect of increasing the strength or reducing the particle size. In general, since the precipitation phase is formed at a temperature lower than Ti, it is an element having a great effect of refining the crystal grain size and strengthening the precipitation by forming the precipitation phase. It also has the effect of lowering the fraction of dissolved C to improve vibration isolation.

In order to obtain the above-mentioned effects, Nb can be contained in an amount of 0.005% or more. However, if the content exceeds 0.5%, an excessive amount of Nb segregates at the grain boundaries and causes grain boundary embrittlement, or the formation of a coarse precipitated phase reduces the effect of suppressing crystal grain growth. .. Further, there is a problem that recrystallization is delayed during the hot rolling process to increase the rolling load.
Therefore, in the present invention, when Nb is added, it can be contained in an amount of 0.005 to 0.5%.

Vanadium (V): 0.005 to 0.5%, and Tungsten (W): 0.005 to 1.0%
Vanadium (V) and tungsten (W) are elements that combine with C and N to form a carbonitride, and in the present invention, the above elements form a fine precipitation phase at a low temperature, so that the effect of precipitation strengthening is achieved. Is big. It also has the effect of lowering the fraction of dissolved C and dissolved N to improve vibration isolation.

In order to obtain the above-mentioned effects, each can be contained in an amount of 0.005% or more, but in the case of V, if it exceeds 0.5%, or in the case of W, it exceeds 1.0%, the precipitation phase. Is excessively coarsened, the effect of suppressing crystal grain growth is reduced, and it causes hot brittleness.
Therefore, in the present invention, 0.005 to 0.5% can be added when V is added, and 0.005 to 1.0% can be added when W is added.

The other component of the present invention is Fe. However, in the normal manufacturing process, unintended impurities from the raw material or the surrounding environment may be inevitably mixed, and this cannot be excluded. Since these impurities are known to any engineer in a normal manufacturing process, all the contents thereof are not specifically mentioned in the present specification.

After preparing the steel slab having the alloy composition as described above, it can be heated, and at this time, it can go through the step of heating in the temperature range of 1150 to 1350 ° C.

If the temperature of the steel slab is too low during heating, a rolling load may be excessively applied during the subsequent hot rolling, so that the temperature can be at least 1150 ° C. or higher.

On the other hand, in the present invention, the larger the austenite crystal grain size (grain size), the higher the fraction of the epsilon martensite phase as the final microstructure, so that the higher the heating temperature is, the more advantageous. Further, the higher the heating temperature, the more advantageous the subsequent hot rolling step can be performed. However, since the present invention contains a large amount of Mn, there is a problem that internal oxidation occurs violently and the surface quality deteriorates when heating is performed at an excessively high temperature. Therefore, the above heating is 1350. It can be carried out at ° C. or lower, and more preferably at 1300 ° C. or lower.

The steel slab heated as described above can be hot-rolled to produce a hot-rolled steel sheet. At this time, it is preferable to perform finish hot rolling at a temperature (FDT (° C.)) that satisfies the following relational expression 1.

[Relational expression 1]
FDT (° C.) ≧ 928 + (480 × C) + (450 × N) + (0.9 × Mn) + (65 × Ti)
(Here, each element means weight content.)

The above relational expression 1 is an expression derived through a large number of experiments, and is an important factor for producing a high manganese steel material having excellent vibration isolation and formability, which is the object of the present invention.

Specifically, the present invention can induce the growth and recrystallization of austenite grains with sufficient size by performing finish hot rolling at a temperature higher than the temperature at which complete recrystallization occurs. The epsilon martensite phase can be stably secured in the subsequent cooling and / or winding steps.

When the temperature during hot rolling for finishing is lower than the temperature derived by the relational expression 1, it becomes difficult to induce the growth and recrystallization of austenite crystal grains, and the epsilon martensite phase is sufficiently formed as the final microstructure. This cannot be done, and there is a risk that an unrecrystallized structure will be formed and the anti-vibration property will be reduced.

Further, at the time of the finish hot rolling, the total rolling reduction ratio can be 80% or more, more preferably 90% or more. When the total reduction ratio is 80% or more during the finish hot rolling, the driving force for recrystallization can be sufficiently secured.

The hot-rolled steel sheet produced as described above can be cooled, and at this time, it is preferable to cool the hot-rolled steel sheet to 700 ° C. or lower.

If the end temperature exceeds 700 ° C during the above cooling, scale will be generated excessively, an excessive process will be required to remove the scale, and problems such as air pollution due to dust will be hindered in post-processing. It is not preferable because it becomes.

In the present invention, cooling may be performed to room temperature, and in this case, there is an effect that further excellent vibration-proof property can be ensured as compared with the high manganese vibration-proof steel manufactured by the existing post-heat treatment step (Table 3 below). See).

Therefore, in the present invention, it is preferable to finish the cooling in the temperature range of 700 ° C. or lower, more preferably 500 ° C. or lower, still more preferably normal temperature to 300 ° C. during the above cooling. As described above, the lower the cooling end temperature, the smaller the amount of residual austenite, which is more advantageous from the viewpoint of securing the epsilon martensite phase in the final microstructure.

On the other hand, the above cooling can be performed by normal water cooling (for example, a cooling rate of 10 ° C./s or more), and when the cooling end temperature is normal temperature to 300 ° C., the cooling end temperature can be secured by rapid cooling. can. The cooling rate at the time of rapid cooling is not particularly limited, but as an example, it can be performed at a cooling rate of 50 ° C./s or more, but it can be performed at 200 ° C./s or less in consideration of equipment specifications. ..
Here, the normal temperature is not particularly limited, but means about 20 to 35 ° C.

In the present invention, after the cooling is completed, the winding step can be further performed at the temperature. This can be selectively performed in consideration of the thickness of the steel material and the like.

The high manganese steel material of the present invention obtained by completing the above-mentioned cooling step contains an epsilon martensite phase with an area fraction of 90% or more and does not contain a completely recrystallized structure, that is, an unrecrystallized structure at all. High vibration isolation and moldability can be ensured.

Hereinafter, the high manganese steel material having excellent vibration isolation and formability according to the other aspect of the present invention will be described in detail.

The high manganese steel material of the present invention can be obtained by the above-mentioned manufacturing process. Further, since it has the above-mentioned alloy composition, the alloy composition of the above-mentioned steel material is replaced by the matters already mentioned.

The high manganese steel material of the present invention is preferably composed of epsilon martensite having an area fraction of 90% or more (including 100%) and a residual austenite phase as a fine structure. In particular, the present invention is a completely recrystallized structure that does not contain any unrecrystallized structure, and can secure excellent anti-vibration properties, and more preferably, it can contain 95% or more of the above-mentioned epsilon martensite phase. ..

As described above, the high manganese steel material of the present invention is subjected to an external impact by effectively removing residual dislocations by complete recrystallization while containing the epsilon martensite phase in a high fraction. Occasionally, the epsilon martensite phase contributes to improved damping performance by increasing the rate at which impact energy is converted to thermal energy.

On the other hand, the high manganese steel material of the present invention does not contain any phase other than the above-mentioned phase as a microstructure, and does not contain, for example, an alpha'(α') -martensite phase at all. Let me make it clear.

In particular, the present invention is excellent in that it can form the epsilon martensite phase in a sufficient fraction even though the high cost heat treatment performed in the production of the conventional high manganese anti-vibration steel is omitted. Formability can also be ensured. Therefore, it can be said that the high manganese steel material of the present invention has an economical and advantageous technical effect as compared with the conventional high manganese vibration-proof steel.

Hereinafter, the present invention will be described in more detail with reference to examples. However, it should be noted that the following examples are merely for exemplifying and explaining the present invention in more detail, and are not for limiting the scope of rights of the present invention. This is because the scope of rights of the present invention is determined by the matters described in the claims and the matters reasonably inferred thereby.

(Example)
Steel slabs having the alloy composition shown in Table 1 below were heated-hot rolled-cooled under the conditions shown in Table 2 to produce each hot-rolled steel sheet. At this time, for comparison, a post-heat treatment was performed on a specific steel grade, and the post-heat treatment was performed at 1000 ° C. for 30 minutes and then air-cooled.

Then, the mechanical properties and fine structure of each of the manufactured hot-rolled steel sheets were measured, and the results are shown in Table 3 below.

At this time, in order to measure the mechanical properties, the yield strength (YS), the tensile strength (TS) and the elongation (T-El and U-El) were measured after preparing the JIS No. 5 tensile test piece. Further, the microstructure was measured using XRD (X-ray diffraction), and the fraction of each phase was derived from the peak intensity of each phase.

Then, as shown in FIG. 5, the loss rate with respect to the deformation rate of 200 to 900 (m / (m × ^10-6 )) was measured by the cantilever method. At this time, the value of the loss rate (X _n = (1 / π) ln (X _n / X _{n + 1} )) at the deformation rate of 900 (m / (m × 10 ^-6 )) is shown in Table 3 below.

（表３において、α’－Ｍはアルファ’－マルテンサイト、γはオーステナイト、ε－Ｍはイプシロンマルテンサイト相を意味する。）

(In Table 3, α'-M means alpha'-martensite, γ means austenite, and ε-M means epsilon martensite phase.)

As shown in Tables 1 to 3 above, the invention steels 1 to 6 which have been subjected to finish hot rolling at a temperature satisfying the alloy composition and manufacturing conditions, particularly the relational expression 1 proposed in the present invention, and have been cooled at 700 ° C. or lower. Is able to secure excellent anti-vibration properties by forming 95% or more of all epsilon martensite phases.

Further, it can be confirmed that all of the above-mentioned invention steels 1 to 6 have excellent formability when the total elongation exceeds 40%.

It can be seen that this has equivalent or better vibration isolation and formability than the conventional high manganese vibration-proof steel (see Comparative Steel 5) that undergoes post-heat treatment.

On the other hand, in the case of the comparative steels 1 to 4 and 6 to 9 which do not satisfy the production conditions of the present invention (relational formula 1 and the like), the alpha'(α') -martensite phase is formed by forming the alpha'(α') -martensite phase. Not only was it inferior in vibration isolation, but the total elongation was less than 40%, and it was also inferior in moldability.

FIG. 1 is a graph showing the value of the loss rate of each test piece at a loss rate of 900 (m / (m × ^10-6 )) according to FDT (° C.).
As shown in FIG. 1, only the invention steels 1 to 6 subjected to finish hot rolling at a temperature satisfying the relational expression 1 of the present invention have a loss rate of 0.05 or more, which is a comparative steel subjected to post-heat treatment. It can be seen that the effect is equal to or higher than that of 5.

FIG. 2 is a graph showing the value of the loss rate of some test pieces at the loss rate of 200 to 900 (m / (m × ^10-6 )).
As shown in FIG. 2, in the case of the invention steel, it can be confirmed that the loss rate increases as the deformation rate increases, which may have an effect equal to or higher than that of the comparative steel 5 subjected to the post-heat treatment. I understand. On the other hand, in the case of comparative steel, it can be confirmed that the loss rate does not exceed 0.020 even if the deformation rate is high.

FIG. 3 shows a microstructure photograph of the invention steel 4, and it can be confirmed that the microstructure was mostly formed by the epsilon martensite phase.

FIG. 4 shows the XRD measurement results of the invention steel 6 and the comparative steel 6.
As shown in FIG. 4, in the comparative steel 6, the peak of the alpha'(α') -martensite phase is observed, whereas in the invention steel 6, only the peaks of the epsilon martensite phase and the austenite phase are observed. Is observed, and it can be confirmed that the intensity of the epsilon martensite phase is further increased.

Claims (10)

By weight%, carbon (C): 0.1% or less, manganese (Mn): 8 to 30%, silicon (Si): 3.0% or less, phosphorus (P): 0.1% or less, sulfur (S) ): 0.02% or less, nitrogen (N): 0.1% or less, titanium (Ti): 1.0% or less (excluding 0%), boron (B): 0.01% or less, balance Fe and The step of heating a steel slab containing other unavoidable impurities at a temperature of 1150 to 1350 ° C;
A step of finishing and hot rolling the heated steel slab to produce a hot-rolled steel sheet; and a step of cooling the hot-rolled steel sheet to 700 ° C. or lower.
A method for producing a high manganese steel material having excellent vibration isolation and formability, wherein the finish hot rolling is performed at a temperature (FDT, ° C.) satisfying the following relational expression 1.
[Relational expression 1]
FDT (° C.) ≧ 928 + (480 × C) + (450 × N) + (0.9 × Mn) + (65 × Ti)
(Here, each element means weight content.) The method for producing a high manganese steel material having excellent vibration-proofing properties and formability according to claim 1, wherein the finish hot rolling is performed at a total reduction rate of 80% or more. The method for producing a high manganese steel material, which has excellent vibration-proofing properties and formability, according to claim 1, wherein the cooling is completed at room temperature to 300 ° C. The method for producing a high manganese steel material having excellent vibration isolation and moldability according to claim 1, which contains an epsilon martensite phase having an area fraction of 90% or more after cooling. The method for producing a high manganese steel material having excellent vibration isolation and formability according to claim 1, further comprising a step of winding after cooling. The first aspect of the present invention, wherein the steel slab further contains at least one of nickel (Ni): 0.005 to 2.0% and chromium (Cr): 0.005 to 5.0% by weight. A method for producing a high manganese steel material having excellent vibration isolation and formability. The steel slabs are in% by weight, niobium (Nb): 0.005 to 0.5%, vanadium (V): 0.005 to 0.5% and tungsten (W): 0.005 to 1.0%. The method for producing a high-tungsten steel material having excellent vibration-proofing properties and formability according to claim 1, further comprising one or more of them. A steel material manufactured by the manufacturing method according to any one of claims 1 to 7.
By weight%, carbon (C): 0.1% or less, manganese (Mn): 8 to 30%, silicon (Si): 3.0% or less, phosphorus (P): 0.1% or less, sulfur (S) ): 0.02% or less, nitrogen (N): 0.1% or less, titanium (Ti): 1.0% or less (excluding 0%), boron (B): 0.01% or less, balance Fe and Contains other unavoidable impurities
A high manganese steel material having a completely recrystallized structure containing epsilon martensite having an area fraction of 90% or more and a residual austenite phase as a fine structure, and having excellent vibration isolation and formability. The eighth aspect of the present invention, wherein the steel material further contains at least one of nickel (Ni): 0.005 to 2.0% and chromium (Cr): 0.005 to 5.0% by weight. High manganese steel with excellent vibration isolation and formability. The steel material has niobium (Nb): 0.005 to 0.5%, vanadium (V): 0.005 to 0.5% and tungsten (W): 0.005 to 1.0% in weight%. The high manganese steel material having excellent vibration isolation and formability according to claim 8, further comprising one or more of them.

Images