JP2002294408A - Iron-based vibration damping alloy and manufacturing method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ferromagnetic iron-based vibration damping alloy having an extremely high loss-factor η of 0.05 or more, and a manufacturing method therefor. SOLUTION: The iron-based vibration damping alloy includes, by mass, 0.007% or less C, 1-3.5% Si, 0.4% or less Mn, 0.02% or less P, 0.01% or less S, 2-9% Cr, 1-20% Co, 0.2-5% Al, 0.007% or less N, and preferably, further 0.0005-0.01% B and/or 0.1-1% Cu, and the balance Fe and unavoidable impurities. In addition, preferably, the alloy has λ100 ×μmax of 0.25 or more, which is the product of magnetostriction constant of orientation (100) λ100 and maximum permeability μmax . The manufacturing method is characterized by heating the alloy to a temperature of Ac3 point or higher and 1200 or less, rolling it to a finishing temperature of Ar1 or higher with the reduction at a temperature of Ar3 +50 deg.C-Ar3 , of 45% or higher, and then heat treating it to keep it at 830 deg.C or higher for 90 minutes or longer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an iron-based damping alloy having high damping properties and a method for producing the same.

[0002]

2. Description of the Related Art Social needs for noise and vibration countermeasures are increasing. Although there are various methods for preventing noise and vibration depending on the object, one method is to suppress the vibration of the material itself. For example, a vibration damping steel sheet in which resin is sandwiched between steel sheets absorbs vibrations due to shear deformation between the resin and the steel sheet, and is a material that has been used in many applications.
There is a limit to its application as a structural material.

[0003] On the other hand, there is a concept of suppressing these by the damping ability of the structural material itself, and a metal material having such a function is called a vibration damping alloy. A typical example is a so-called ferromagnetic damping alloy utilizing hysteresis by irreversible motion of domain wall motion under the action of alternating stress due to vibration. For example, Japanese Patent Application Laid-Open No. 4-99148 and Japanese Patent Application Laid-Open No.
No. 18, JP-A-6-220583, JP-A-6-220583
No. 2,589,982, etc., an iron-based material containing Al, Si, Cr and the like, and an iron-based material having enhanced vibration damping properties by strengthening the (100) orientation texture of a steel material as disclosed in JP-A-10-72643. There are materials.

The loss coefficient η, which is an index indicating the damping performance of these existing ferromagnetic damping alloys, is at most 0.0
It is about 4. The damping property of the damping steel sheet obtained by sandwiching the resin on the steel sheet was slightly inferior to that of the loss coefficient η of about 0.1 or more. In addition, the ferromagnetic material type damping alloy has a property that the vibration damping property is inferior when distortion is impossible by processing or welding. When used as a structural material, processing and welding are indispensable and load of strain on the material is unavoidable, so if heat treatment to remove the strain cannot be performed after processing or welding, practical use In many cases, sufficient vibration suppression performance was not exhibited. For this reason, the iron-based damping alloy is not widely used as a structural material even though it is a relatively inexpensive material.
For this reason, an iron-based damping alloy material that has higher damping properties than conventional iron-based damping alloys and can exhibit practically effective damping performance even when a certain amount of strain is applied Is desired.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a ferromagnetic material which has an extremely high loss coefficient η of 0.05 or more, maintains the workability and weldability of the conventional material, and is easy to handle as a structural material. An object of the present invention is to provide an iron-based damping alloy and a method for manufacturing the same.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and basically utilizes a vibration damping effect caused by hysteresis due to irreversible motion of domain wall motion under the action of alternating stress due to vibration. It is based on a pure iron-based component that has reduced as much as possible impurities and inclusions that are harmful to domain wall movement. The gist of the present invention is as follows: (1) In mass%, C: 0.007% or less, Si: 1 to
3.5%, Mn: 0.4% or less, P: 0.02% or less,
S: 0.01% or less, Cr: 2 to 9%, Co: 1 to 20
%, Al: 0.2 to 5%, and N: 0.007% or less, the balance being Fe and inevitable impurities.

(2) B: 0.0005 to 0.5% by mass.
01%, Cu: 0.1 to 1%, one or two
The iron-based system as described in (1) above,
Vibration alloy. (3) (100) azimuthal magnetostriction constant λ₁₀₀And the maximum permeability μ
_maxWith λ₁₀₀× μ _maxIs 0.25 or more
The iron-based system according to the above (1) or (2),
Vibration alloy.

(4) In the production of the vibration damping alloy according to any one of the above (1) to (3), _three or more Ac points
Heating to a temperature of 200 ° C. or less, Ar ₃ + 50 ° C. to Ar ₃
The rolling reduction at temperature is 45% or more, and the rolling finish temperature is Ar
_A method for producing an iron-based vibration damping alloy, characterized in that hot rolling is performed so as to be ₁ or more, and heat treatment is performed at 830 ° C. or more after the rolling for 90 minutes or more.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS When a ferromagnetic material is magnetized, its length changes, and this phenomenon is called magnetostriction. Conversely, when stress is applied to the ferromagnetic material, there is an effect that the internal magnetic domain structure changes.
This change in the magnetic domain structure, that is, the irreversible mobility of the domain wall motion causes hysteresis when vibrating, and attenuates the vibration by an amount corresponding to the hysteresis energy. Therefore, a material having a remarkable magnetostriction, that is, a material having a large magnetostriction constant, has a larger hysteresis loss. However, a material having a large magnetostriction constant does not always have a large loss coefficient.

As a result of various studies on the relationship between the magnetostriction of the ferromagnetic material and various physical property values and the loss coefficient, the loss coefficient has a very close relationship between the magnetostriction constant and the maximum magnetic permeability of the material. It has been found that there is a very good correlation between the loss coefficient η and the product of the magnetostriction constant in the (100) direction and the maximum magnetic permeability (λ ₁₀₀ × μ _max ). Specifically, FIG.
As shown in the above, a loss coefficient η of 0.05 or more can be obtained by selecting an appropriate alloy component and a manufacturing method so that λ ₁₀₀ × μ _max is 0.25 or more.

Although the magnetostriction constant λ ₁₀₀ is affected by the structural factor of the material, the effect of the alloy component is generally large. Although the maximum magnetic permeability μ _max is greatly affected by the alloy components, it is also greatly affected by the structure factor, that is, the crystal grain size, the amount of inclusions and impurities. Generally, an element that increases magnetostriction often lowers magnetic permeability. Cr increases the magnetostriction, but on the other hand decreases the magnetic permeability by adding a large amount,
On the contrary, the damping performance may be reduced. Si and Al are effective elements for improving the magnetic permeability, but there is an optimum addition amount for the magnetostriction, and the magnetostriction is reduced at a certain level or more.

The present inventors have found that Co is the most effective element that significantly improves the magnetostriction constant λ ₁₀₀ and hardly lowers the maximum magnetic permeability μ _max .
Co is an essential element for obtaining a loss coefficient η of 0.05 or more in the present invention. The maximum magnetic permeability μ _max is greatly influenced by the structure factor, particularly the crystal grain size. That is, the crystal grain size is desirably as large as possible from the viewpoint of reducing the crystal grain boundaries that hinder the movement of the domain wall.
Therefore, in order to obtain a high maximum magnetic permeability μ _max , a manufacturing method for uniformly increasing the crystal grain size as well as the alloy component is important. Specifically, rolling at a high rolling reduction is performed in a relatively low temperature range to sufficiently introduce a rolling strain which is a driving force for crystal grain growth, and coarse grains are obtained by annealing in a suitable high temperature range.

Next, the reasons for limiting the present invention will be described. In addition,
% Means mass%. C is either itself or Cr
It is an element that forms carbides and significantly inhibits uniform grain growth due to grain boundary precipitation during the heat treatment temperature raising process. However, since carbides hardly form a solid solution at 800 ° C. or higher when the content is 0.007% or less, uniform grain growth can be achieved by setting the heat treatment temperature to 800 ° C. or more. Therefore 0.007%
Reduce to below.

Si improves magnetostriction when added at 1% or more, and becomes maximum at about 2%. However, if added in excess of 3.5%, the magnetostriction is rather reduced. It is also effective for increasing the magnetic permeability. Therefore, the addition amount is limited to 1% or more and 3.5% or less. Mn does not have a significant effect of improving magnetostriction, and on the contrary, causes a decrease in magnetic permeability. Therefore, the addition amount is set to 0.4% or less. Since both P and S generate nonmetallic inclusions to inhibit grain growth and also reduce toughness, it is necessary to reduce P and S as much as possible. P is 0.02% or less, and S is 0.01% or less.

Cr has a remarkable effect of improving magnetostriction. However, if it exceeds 3%, the second phase (pearlite) tends to be formed, and as the amount of addition increases, the magnetic permeability decreases. If it exceeds 9%, the effect of improving magnetostriction is offset and the loss coefficient decreases. Therefore, the addition amount is 2% or more, 9%
Or less, preferably 3% or less. Co has a remarkable effect of improving magnetostriction with almost no effect on magnetic permeability, but its effect is insufficient when added to less than 1%. On the other hand, if the addition exceeds 20%, the alloy cost increases, so the addition is set to 1% or more and 20% or less.

Al is added in an amount of 0.2% or more to coarsen AlN and to prevent precipitation of fine AlN which is harmful to coarsening. It is also very effective as a ferrite former. However, if added in excess of 5%, the toughness will be significantly reduced, so the amount added should be between 0.2% and 5%. When toughness is important, the upper limit is preferably 1%. N
In order to reduce magnetic properties even in the solid solution state or when precipitated as a nitride, it is desirable to reduce as much as possible, and it is 0.007% or less.

B can be added for the purpose of improving the strength, but the effect is almost constant at 0.0005% or more. Further, since excessive addition may lower the magnetic permeability, the upper limit in the case of adding is 0.01%. Cu
Can also be added for the purpose of improving the strength. When added, the effect cannot be obtained unless it is added in an amount of 0.1% or more. On the other hand, the effect is almost saturated with the addition of 1%, and excessive addition lowers the magnetic permeability.

Next, the manufacturing method will be described. The heating temperature is usually, for the Ac ₃ than is the heating of thick plate and hot rolled plates of steel, and do not coarsen before hot rolling grain 1
200 ° C. or less. Further, the heat treatment after the hot rolling, to grow sufficiently grains, the grain size to some extent finely controlled uniformly, and for introducing a sufficient rolling strain as a driving force for grain growth, Ar ₃ The rolling reduction at the temperature of + 50 ° C. to Ar ₃ must be 45% or more.

The heat treatment temperature after rolling is about 200 μm
It is performed in order to secure a uniform crystal grain size of the above size, and for this purpose, it is necessary to heat to 830 ° C. or more.
If the temperature exceeds 920 ° C., the grain growth rate is increased, and the control of the crystal grain size becomes unstable, such as in rare cases where abnormal grain growth occurs. The vibration damping alloy of the present invention can exhibit high vibration damping performance as well as a hot rolled plate or a thick plate even when used as a material for a steel pipe.

[0020]

EXAMPLES A steel slab having the composition shown in Table 1 was prepared, and a hot-rolled plate and a thick plate having a thickness of 3 to 50 mm were produced under the production conditions shown in Table 2. The (100) direction magnetostriction constant λ ₁₀₀ was measured by using a strain gauge by collecting a single crystal sample from a sufficiently coarse thick plate. The maximum magnetic permeability μ _max was determined by measuring a DC magnetization curve using a ring-shaped sample having the original thickness. Furthermore, the loss coefficient η is
A plate-shaped test piece having an original thickness of 40 mm x 400 mm in length was processed and measured by a mechanical impedance method. In the table, the underlined portions deviate from the patent range or do not reach the target values of the respective characteristics.

[0021]

[Table 1]

Of the alloy plates shown in Table 2, 1-A to 7-G are examples of the present invention, and 8-H to 23-B are comparative examples. Table 2 shows various characteristics of these steel sheets manufactured under the manufacturing conditions shown in Table 2. Examples of the steel plates 1-A to 7-G all have λ ₁₀₀ × μ _max of 0.25 or more, and as a result, exhibit a very high vibration damping performance with a loss coefficient η of 0.05 or more. . On the other hand, Comparative Example 8-H has a high C and a small crystal grain size, and a low magnetic permeability, so that the loss coefficient is less than 0.05. 9-I and 10-J have a low magnetostriction constant or magnetic permeability and a loss coefficient η of less than 0.05 because Si is out of the range of the present invention.

[0023]

[Table 2]

Further, since 11-K has a low Mn,
L is high in P, and 13-M is high in S, so 14-N
Is high in Cu, 16-P is high in Cr,
R is low in Al and 20-T is high in N, so 21-
Since B has a high heating temperature, 22-B is Ar ₃ + 50 ° C.
Since the rolling reduction in Ar ₃ is small, the annealing temperature of 23-B is low, so that the permeability is low and the loss coefficient η is 0.0
Less than 5. 15-O has low Cr and 17-Q has Co
And the magnetostriction is low, so that the loss coefficient η is less than 0.05.

[0025]

According to the present invention, a ferromagnetic iron-based material having an extremely high loss coefficient η of 0.05 or more, and maintaining the workability and weldability comparable to conventional materials and easy to handle as a structural material. It is possible to provide a vibration damping alloy and a method for producing the same, and it can be said that the industrial value thereof is extremely high.

[Brief description of the drawings]

FIG. 1 is the product of (100) azimuthal magnetostriction constant and maximum magnetic permeability (λ
FIG. 4 is a diagram showing a relationship between ( ₁₀₀ × μ _max ) and a loss coefficient η.

 ──────────────────────────────────────────────────の Continued on the front page F term (reference) 4K032 AA01 AA02 AA04 AA10 AA12 AA14 AA16 AA21 AA27 AA29 AA32 BA01 CA02 CB01 CB02 CF03

Claims (4)

[Claims] 1. mass%, C: 0.007% or less, Si: 1 to 3.5%, Mn: 0.4% or less, P: 0.02% or less, S: 0.01% or less, Fe: 2 to 9%, Co: 1 to 20%, Al: 0.2 to 5%, N: 0.007% or less, with the balance being Fe and unavoidable impurities. Vibration alloy. 2. The method according to claim 1, further comprising one or more of B: 0.0005 to 0.01%, and Cu: 0.1 to 1% by mass%. Iron-based damping alloy. 3. The iron according to claim 1, wherein a product of (100) azimuth magnetostriction constant λ ₁₀₀ and maximum magnetic permeability μ _max λ ₁₀₀ × μ _max is 0.25 or more. System damping alloy. 4. A preparation of damping alloy according to item 1 to any one of claims 1 to 3, and heated to a temperature of 1200 ° C. or more ₃ points Ac, reduction in Ar ₃ + 50 ° C. to Ar ₃ temperature Hot rolling is performed so that the rolling finish temperature is Ar ₁ or higher.
A method for producing an iron-based vibration damping alloy, comprising performing heat treatment for holding for at least one minute.