JP2637371B2 - Method for producing Fe-Mn-based vibration damping alloy steel - Google Patents

Abstract

An Fe-Mn vibration damping alloy steel having a mixture structure of epsilon , alpha ' and gamma . The alloy steel consists of iron, manganese from 10 to 24 % by weight and limited amounts of impurities. The alloy steel is manufactured by preparing an ingot at a temperature of 1000 DEG C to 1300 DEG C for 12 to 40 hours to homogenize the ingot and hot-rolling the homogenized ingot to produce a rolled alloy bar or plate, performing solid solution treatment on the alloy steel at 900 DEG C to 1100 DEG C for 30 to 60 minutes, cooling the alloy steel by air or water, and cold-rolling the alloy steel at a reduction rate of below 30 % at around room temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an Fe-Mn-based vibration damping alloy steel which can be produced at a low price while having excellent vibration damping ability, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, anti-vibration alloys have been widely used for various mechanical parts which are sources of vibration and noise in accordance with the trend of high grade and high precision of aircraft, ships, automobiles and various machines. The reality is that research and development is being actively pursued in response to increasing demand for vibration alloys.

When the conventionally developed and used vibration damping alloys are classified by damping mechanism, a composite type (Fe—C—Si, A
1-Zn), ferromagnetic type (Fe-Cr, Fe-Cr-A)
1, Co—Ni), dislocation type (Mg—Zr, Mg—Mg ₂₎
Ni) and twin type (Mn-Cu, Cu-Al-Ni,
Ni-Ti). Such vibration-proof alloys have excellent damping performance, but have poor mechanical properties and cannot be used for anything other than special applications, and because they contain many expensive elements, they cause an increase in the price of alloy materials. As a result, industrial applications have been extremely limited.

In order to solve such a problem, there is Korean Patent No. 57,437 filed by the applicant on August 27, 1990 and registered on December 16, 1992. The above alloy is Fe-Mn having a martensitic structure.
(10-22%)-based vibration damping alloy steel, and its manufacturing method is 100% Fe-Mn (10-22%) ingot.
Γ⇔ε repeating transformation type Fe characterized by being homogenized at 0 ° C to 1300 ° C for 20 to 40 hours, hot-rolled, heated at 900 to 1100 ° C for 30 minutes to 1 hour, and then air-cooled or water-cooled. -A Mn-based anti-vibration alloy, wherein the damping mechanism is completely different from the above-described conventional damping mechanism, and is characterized by absorbing vibration energy during movement of the ε / γ interface by vibration stress.

[0005] However, the present applicant is not satisfied with the above results, and devote his utmost to the development of a more excellent vibration damping alloy steel, and as a result, develops an alloy of the present invention having a better vibration damping ability than the above alloy. Succeeded.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an Fe-Mn based vibration damping alloy which has excellent vibration damping ability and can be produced at a low price.
It is to provide a method for producing steel .

[0007]

In order to achieve the above object, the alloy of the present invention has a composition range of Mn which is slightly wider than that of the alloy. In the production method, a cold working step is included in the production step of the alloy. It is characterized by being added.

That is, the Fe—Mn vibration damping of the present invention.
The method for producing alloy steel is as follows: first, manganese is 10 to 24% by weight,
0.2% by weight or less of carbon and 0.4% by weight of silicon as impurities
Hereinafter, a molten metal containing 0.05% by weight or less of sulfur and 0.05% by weight or less of phosphorus and the balance being Fe is cast.
To produce ingots.

Next, the above-mentioned ingot was put into a
After homogenizing at 300 ° C. for 12 to 40 hours and performing hot rolling, further heating at 900 to 1100 ° C. for 30 to 60 minutes and air-cooling or water-cooling, and then cooling it at around room temperature (25 ° C. ± 50 ° C.). %, Characterized in that cold working is performed at a draft of not more than%.

[0010]

The reason why the homogenization treatment conditions are limited to 1000 to 1300 ° C. for 12 to 40 hours is to make the composition of manganese uniform, and therefore 1000 to 130 hours.
This is because the ingot is heated at 0 ° C., but if the temperature is lower than 1000 ° C., the diffusion rate is low, and if the temperature is increased to 1300 ° C. or higher, there is a risk that a local melting phenomenon of crystal grain boundaries may occur.

Heating at a heat treatment temperature of 900 to 1100 ° C. for 30 to 60 minutes requires that the crystal grains become coarser at 1100 ° C. or more and the tensile strength becomes lower, and that at 900 ° C. or less, less ε martensite is formed, so that attenuation occurs. Performance becomes lower.

When the composition of manganese is 10 to 24% by weight, when the content of manganese is 10% or less, α 'martensite becomes a single phase and hardly has a vibration damping effect.
In a 28% manganese alloy, ε and γ coexist, and the ε / γ interface is present. Cold working at around room temperature can generate ε without generating slip dislocations, thereby increasing the ε / γ interface area. That is, the range of manganese composition in which ε can be generated by cold working at around normal temperature without generation of slip dislocation to increase the ε / γ interface area is 10 to 24.
% Manganese.

[0013] Then, cold working is carried out at around normal temperature for 30 minutes.
% Of the manganese alloy having the above composition
The interface has vibration damping ability due to the existence of the interface. However, by performing cold working, more fine ε is generated inside γ, and the total interfacial area of ε / γ is increased. In order to exhibit excellent vibration damping ability, if the amount of cold working is increased to 30% or more, coalescence of ε martensite plates occurs, the ε / γ boundary area decreases, and α ′ martensite changes from ε to α ′ martensite. Generated, which suppresses the movement of the ε / γ interface, and causes many dislocations to be generated inside ε and γ, causing an interaction with the ε / γ interface, thereby making it difficult to move the ε / γ interface. This is because the vibration damping ability is inferior.

In the method for producing an alloy steel according to the present invention, as impurities, 0.2% by weight or less of carbon, 0.4% by weight or less of silicon, 0.05% by weight or less of sulfur and 0.05% by weight of phosphorus.
The reason for limiting to the following is that if too much impurities are contained, the impurity element diffuses into the ε / γ interface to fix the interface, making it difficult for the ε / γ interface to move, resulting in poor attenuation.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

At the time of producing the alloy of the present invention, 10 to 24% by weight of manganese is weighed so that the balance is made up of Fe, and the temperature of the furnace is heated to 1500 ° C. or more in a melting furnace, and Fe is first added. After melting, manganese is charged and dissolved.

Next, the ingot is cast and
After homogenizing at 1300 ° C for 12 to 40 hours,
It is manufactured by hot rolling to a predetermined shape.

Thereafter, after heating at a temperature of 900 to 1100 ° C. for 30 to 60 minutes and air-cooling or water-cooling, when cold-working to around 30% or less at around normal temperature (25 ° C. ± 50 ° C.), Fe— It becomes a Mn-based alloy steel.

The reasons for limiting the above conditions in the present invention are as follows.

[0020] The homogenization treatment conditions are 1000-1300 ° C.
The reason for limiting to 12 to 40 hours is that manganese, a main element of the alloy of the present invention, segregates during casting, so that the cast ingot is heated at a high temperature to diffuse high-concentration manganese into low-concentration areas. Manganese composition must be uniform.

For this reason, the ingot is heated at 1000 to 1300 ° C., but if the temperature is lower than 1000 ° C., the diffusion rate is slow and it takes 40 hours or more to homogenize, thereby increasing the production cost. When the temperature is increased to 1300 ° C. or more, the time for homogenization can be shortened to within 12 hours, but there is a risk that a local melting phenomenon of the grain boundaries where manganese is segregated during casting may occur. Exists. Therefore, it is most preferable to perform the homogenization treatment at 1000 to 1300 ° C. for 12 to 40 hours.

Heating at a heat treatment temperature of 900 to 1100 ° C. for 30 to 60 minutes means that when heating at a temperature of 1100 ° C. or more, the temperature is too high, the crystal grains become coarse and the tensile strength becomes low. Although the temperature is extremely low, the crystal grains become finer and the tensile strength increases, but Ms
Becomes low and ε-martensite is generated in a small amount, so that the damping ability becomes low. The most preferable condition having both the damping ability and the tensile strength is 30 to 6 at 900 to 1100 ° C.
Heat for 0 minutes.

When the composition of manganese is 10 to 24% by weight, α 'martensite is formed up to 10% manganese as shown in the binary phase diagram of the Fe—Mn alloy in FIG. Ε + α '+ γ for 15% manganese
Are formed, and at 15 to 28% manganese, ε
A two-phase mixed structure of + γ is formed.

As described above, the Fe-Mn-based damping mechanism is as follows.
Vibration stress absorbs vibrational energy during the movement of the ε / γ interface to exhibit damping ability, so that 10% or less of manganese becomes an α 'martensite single phase and hardly has a vibration damping effect, and 10 to 28% of manganese In the alloy, ε and γ coexist, and due to the existence of the ε / γ interface, vibration damping ability appears.

However, when an appropriate amount of cold working is applied to the alloy at around room temperature (25 ° C. ± 50 ° C.), more stress organic ε martensite is generated and the total ε / γ interfacial area increases. The damping ability is significantly improved compared to the state before the cold working. However, the amount of manganese is 24%
Above this, the austenite Neel temperature (T _N ; the magnetic transformation temperature that changes from paramagnetism to antiferromagnetism) becomes much higher than room temperature, so that austenite is stabilized, and a large amount of machining is performed around room temperature. By giving the degree, ε martensite is generated, and at the same time, a number of dislocations are generated by operating the austenitic slip system. Such dislocation does not bring about the effect of improving the damping ability for the movement of the ε / γ interface during vibration. Therefore, the reason why the manganese composition is limited to 10 to 24% is that the range of manganese composition in which ε can be generated by cold working at around normal temperature without generation of slip dislocation to increase the ε / γ interface area is 10%. This is because manganese is ２４24%.

Then, cold working is performed at around normal temperature for 30 minutes.
%, The manganese alloy has a ε /
Although it has a γ interface and has a vibration damping capacity, it performs cold working to generate more fine ε inside γ and increases the total interfacial area of ε / γ before cold working. This is to exhibit better vibration damping ability.

However, limiting the cold working to 30% or less means that if the amount of cold working is increased to 30% or more, coalescence of ε martensite plates occurs and the ε / γ boundary area decreases, Α ′ martensite is generated from ε /
The movement of the γ interface is suppressed, and many dislocations are generated inside ε and γ, and the interaction with the ε / γ interface occurs to make the movement of the ε / γ interface difficult. It is.

In the alloy produced by the method of the present invention, as impurities, 0.2% by weight or less of carbon, 0.4% by weight or less of silicon, 0.05% by weight or less of sulfur and 0.05% by weight of phosphorus.
The reason for limiting the content to not more than% by weight is that if too much impurities are contained, the impurity element diffuses into the ε / γ interface to fix the interface, making it difficult for the ε / γ interface to move, resulting in poor attenuation. is there.

Next, the alloy produced by the method of the present invention will be described.
The characteristics of the steel will be described with reference to FIGS. 1 to 4 and examples of Tables 1 and 2.

Table 1 shows the results of measuring the vibration damping ability of the alloy manufactured by the method of the present invention and the conventional alloy according to the working process. It can be seen that the alloy has a very excellent damping ability as compared with the alloy which is not cold-worked, indicating that the alloy has an excellent damping effect as compared with the conventional technology.

[0031]

[Table 1]

FIG. 1 shows the Fe side of the Fe--Mn binary phase diagram which is the basis of the present invention. The transformation point of each phase is determined by a thermal dilatometer while cooling at a cooling rate of 3 ° C./min. Measured. In FIG. 1, α ′ martensite is generated up to 10% Mn, three phases ε + α ′ + γ exist at 10-15% Mn, and two phases ε + γ exist at 15-28% Mn in the mixed structure. However, at 28% Mn or more, a γ single phase exists.

FIG. 2 shows the results of measuring the volume% of each phase by X-ray diffraction analysis when each Mn alloy was heated to 1000 ° C. and air-cooled at room temperature. As shown in the measurement results as shown in FIGS. 1 and 2 and Table 2, the α ′ martensitic structure alloy has a very small vibration damping capacity, and the alloy having the ε + α ′ + γ mixed structure has a very large vibration damping capacity. It can be seen that the tensile strength is also excellent.

[0034]

[Table 2]

The reason that the alloy having the mixed structure of ε + α ′ + γ has a larger vibration damping ability than the α ′ martensite alloy is that the lower structure of α ′ martensite is dislocation, and the vibration energy is absorbed by the dislocation movement. On the other hand, ε + α '+
As described above, an alloy having a mixed structure of γ moves the ε / γ interface when the material is subjected to vibration stress, and at this time, exhibits high vibration damping ability because it absorbs vibration energy.

FIG. 3 shows the specific damping capacity (SD
C: Specific alloying of the present invention having a specific damping capacity change. The SDC increases with the increase of the cold working degree, and shows the maximum damping capacity at about 10 to 20% of the working degree. When the cold working degree further increases, the SDC increases.
When DC is reduced and the working ratio is increased to approximately 30% or more, the damping ability is inferior to the state without cold working. Therefore, in the present invention, the cold working for improving the damping ability is limited to 30% or less. did.

FIG. 4 shows a comparative steel manufactured by the method of the present invention.
4 shows a free vibration damping curve before and after cold working with respect to a given alloy steel. This is a torsion (torsiona
l) Using a pendulum type attenuation measuring device, the maximum surface shear deformation rate γ
= 8 × 10 ⁴ with a rod-shaped specimen. The comparative steel (Fe-4% Mn) had not only a small damping capacity after water cooling (FIG. 4 (A)), but the damping capacity was not improved even when 15% cold work was applied [FIG. 4 (B). )]. However, one of the alloys manufactured by the method of the present invention, Fe-17% Mn, has a remarkable amplitude decay phenomenon even after water cooling at a high temperature (FIG. 4 (C)). It can be seen that the amplitude damping ability phenomenon is more remarkable when 15% of processing is given [FIG. 4 (D)].

[0038]

As described above, according to the present invention, it is possible to obtain a vibration damping alloy having excellent vibration damping ability and superior mechanical properties such as tensile strength as compared with the prior art alloy.

[Brief description of the drawings]

FIG. 1 is a binary phase diagram of an Fe—Mn alloy.

FIG. 2 is a diagram showing the amount of transformation of an Fe—Mn alloy at room temperature.

FIG. 3 is a diagram showing a change in damping capacity according to the working ratio of an Fe-17% Mn alloy.

FIGS. 4A and 4B are diagrams showing free vibration amplitude attenuation curves after cold working of an Fe—Mn alloy, respectively, wherein FIG.
Before cold working (water-cooled state) of alloy, (B) is Fe-4% M
(C) shows the state before the cold working of the Fe-17% Mn alloy (in a water-cooled state), and (D) shows the state after the cold working of the Fe-17% Mn alloy.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor, Rong Chen 211, Yato-dong, Bundang-gu, Seongnam-si, Gyeonggi-do, Republic of Korea 401-406 Sumiko Apartment (72) Inventor Kim Jong ▲ Chioru ▼ Gangnam, Seoul, South Korea District ▲ ぽ ▼ Yi-dong 168-3 (72) Inventor Tanaka ▲ Han ▼ Duck Modern Apartment 24-1006 Gangnam-gu, Gangnam-gu, Seoul, Republic of Korea 24-1006 (72) Inventor Taka Yongsan Seoul, Seoul Special City Road 53-7 Water Stream 1-5, Mine District (56) References JP-A-5-255813 (JP, A) JP-A-62-142222 (JP, A) JP-A-62-133045 (JP, A)

Claims (1)

(57) [Claims] 1. The composition contains 10 to 24% by weight of manganese, 0.2% by weight or less of carbon, 0.4% by weight or less of silicon, 0.05% by weight or less of sulfur, and 0.05% by weight or less of phosphorus as impurities. A molten metal composed of Fe is cast to form an ingot, which is heated at 1000 to 1300 ° C. for 12 hours.
Hot rolling by homogenizing for ~ 40 hours, 900 ~ 1
The mixture was further heated at 100 ° C. for 30 to 60 minutes, air-cooled or water-cooled at room temperature, and cooled to room temperature (25 ° C. ± 50
(C) cold working at a rolling reduction of 30% or less at 30 ° C).