JPH09176780A - High strength steel excellent in damping characteristic and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high damping alloy for structural use material, excellent in damping characteristic as well as in toughness. SOLUTION: This steel has a composition consisting of, by weight, <=0.02% C, 0.01-<0.5% Si, 0.2-2.5% Mn, <=0.010% P, <=0.005% S, <0.5% Cr, 0.002-0.060% Al, <=0.006% N, and the balance Fe with inevitable impurities and also has >=2.5 (200) diffraction intensity ratio.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-strength damping alloy having a high damping property and a high-strength damping alloy having a high toughness as a structural material for ships, bridges, industrial machines and buildings. is there.

[0002]

2. Description of the Related Art Recently, materials for ships, bridges, industrial machines, and buildings tend to be required to have high vibration damping properties in addition to strength and toughness, which are basic characteristics of structural materials. That is, for example, when running on a high-speed railway on a bridge or in large-scale civil engineering,
The present invention aims to solve the problems of suppressing noise and vibration during construction work by the damping effect of the structural material itself and having sufficient toughness as a structural member.

[0003] Conventional iron-based materials used for members intended for damping performance in place of resin sandwich-type damping steel sheets have high hysteresis due to irreversible motion of domain wall motion under the action of alternating stress due to vibration. In order to obtain a vibration-damping property, a material to which Al and Si are added, and
And a material to which is positively added.

As an example of the former, Japanese Patent Laid-Open No. 4-99148
As described in Japanese Patent Publication, the Al content is up to 7.05% and S
There is a ferromagnetic damping alloy with i added up to 4.5%. An example of the latter is a ferromagnetic damping alloy with 8 to 30% of Cr as described in JP-A-52-73118. There are vibration alloys. Further, in JP-A-6-220583 and JP-A-5-302148, Mn is 0.
There is a ferromagnetic damping alloy containing 1 to 0.2% or less and 1 to 5% of Cr. Further, the inventors have previously proposed a ferromagnetic damping alloy to which 0.2 to 2.5% of Mn and 1 to 5% of Cr are added.

Also, Ryohei Tanaka, damping material (its function and application), as a ferromagnetic alloy in p192 to 197 issued by Kousendo in March 1992, external stress causes movement of magnetic domain walls, which causes hysteresis energy to cause vibration energy. Described to be absorbed.

[0006]

However, among these alloys, the alloy described in Japanese Patent Application Laid-Open No. 4-99148 contains a large amount of Al and Si.
This leads to the formation of system inclusions, which act as fracture initiation points, resulting in a decrease in toughness.

Further, the alloy described in Japanese Patent Laid-Open No. 52-73118 has an excessive addition of Cr, so that similarly to the above, the toughness is lowered due to the formation of Cr-based inclusions. Furthermore, JP-A-6-22
The steel materials described in Japanese Patent No. 0583 and Japanese Patent Application Laid-Open No. 5-302148 do not have a viewpoint of preventing deterioration of toughness and have low toughness. In addition, although the steel materials proposed by the inventors have been improved, further improvement in vibration damping property has been desired.

In the literature of damping materials, the mechanism of damping alloys is written, and there is no description about the improvement measures, specific component systems, manufacturing methods, or methods for simultaneously satisfying toughness in addition to damping properties. . An object of the present invention is to provide a high-strength damping alloy having excellent damping properties and damping properties and high toughness.

[0009]

The gist of the present invention is as follows. (1)% by weight, C: 0.02% or less, Si: 0.01
Above, less than 0.5%, Mn: 0.2 to 2.5%, P:
0.010% or less, S: 0.005% or less, Cr: 0.
Less than 5%, Al: 0.002 to 0.060%, N: 0.
A high-strength steel excellent in vibration damping property, containing 006% or less, consisting of balance Fe and unavoidable impurities, and having a (200) diffraction intensity ratio of 2.5 or more.

(2) Cu: 0.05-2.5 by weight%
%, Ni: 0.05-2.5%, Mo: 0.05-4.
5%, Nb: 0.005 to 0.2%, V: 0.005 to
0.2%, Ti: 0.005 to 0.1%, B: 0.00
The high-strength steel excellent in vibration damping property according to (1) above, which contains at least one of 03 to 0.005%.

(3) Ca: 0.001 to 0.
05%, REM: 0.001 to 0.10%, and at least one or more of them are contained. The high-strength steel excellent in vibration damping property according to the above (1) or (2). . (4) The high-strength steel excellent in vibration damping property according to any one of the above (1) to (3), characterized in that high toughness is ensured by setting the crystal grain size to 100 μm or less.

(5) The heating temperature is 1000 to 1150 ° C.,
And a reduction ratio of 850 ° C. or lower is 30 to 70%, and further, hot rolling is performed at a rolling finishing temperature of 750 ° C. or lower, followed by cooling to room temperature, and tempering or annealing heat treatment in a temperature range of 600 to 900 ° C. The above (1)-
The method for producing a high-strength steel excellent in vibration damping property according to any one of (4).

(6) Rolling finishing temperature range is 600 to 75
The above (5) characterized in that hot rolling is performed at 0 ° C.
A method for producing a high-strength steel having excellent vibration damping properties as described. (7) Roll finishing temperature range is Ar ₁ -20 ° C to Ar ₁ +
The method for producing high-strength steel excellent in vibration damping property according to (5) or (6) above, characterized in that hot rolling is performed at 50 ° C.

[0014]

The present invention has been made in view of the above circumstances, and in order to obtain high damping characteristics due to hysteresis due to irreversible motion of domain wall movement under the action of alternating stress due to vibration, the It is based on pure iron-based components in which the elements that cause harmful harmful elements, inclusions, and precipitates, interfere with domain wall movement, and greatly impair vibration damping are minimized.

Further, in the past, since the crystal grain boundary hinders the domain wall movement, the vibration damping property was improved only by coarsening the grain. However, as a result of various studies by the inventors, the vibration damping by the coarsening has been performed. As an alternative to the method for improving the vibration resistance, it has been found that the vibration damping property is significantly improved by increasing the (200) diffraction intensity. By increasing the (200) diffraction intensity, the <100> orientation parallel to the steel sheet surface is strengthened. That is, the direction of easy magnetization is strengthened in a direction parallel to the steel sheet surface. It is a new discovery that the damping property is improved by strengthening the easy magnetization direction. It was found that the damping property is improved by setting the (200) diffraction intensity ratio to 2.5 or more.

If the (200) diffraction intensity ratio is 2.5 or more, a loss coefficient of 0.015 or more, which is an index of the vibration damping property, can be secured. Therefore, from the viewpoint of vibration damping performance only (200)
The higher the diffraction intensity ratio, the better, but in consideration of other steel properties such as toughness, the practical (200) diffraction intensity ratio is 2.
The range of 5 to 12.0 is preferable, and as a result, it is preferable to secure the loss factor of 0.015 to 0.05.

Here, the (200) diffraction intensity ratio was obtained by measuring the (200) diffraction intensity in the plate thickness direction with X-rays and determining the ratio to the (200) diffraction intensity of the random sample material. As a result of studying the plate surface, 1/2 thickness and 1/4 thickness in the plate thickness direction, the (200) diffraction intensity ratio is 1 even at the maximum value.
It was about 5.

In order to increase the (200) diffraction intensity ratio, it is necessary to carry out low-temperature rolling.
This can be achieved by setting the rolling reduction at 0 ° C. or less to 30% or more. Therefore, the rolling finishing temperature is usually 750 ° C. or lower. Further, as a result of a detailed study for improving the vibration damping property, it was found that by setting the rolling finishing temperature to Ar ₁ −20 ° C. to Ar ₁ + 50 ° C., the (200) diffraction intensity ratio was further improved and the vibration damping property was further improved. Found out.

Further, Mn was found as an element capable of significantly increasing the strength without impairing the vibration damping property and the toughness. By adding Mn in an amount of 0.2% or more, it is possible to achieve both the vibration damping property and the strength, or to improve all of the vibration damping property, the strength and the toughness.

In order to improve the toughness, the crystal grain size is 10
It is preferably 0 μ or less. To this end, in the above-described manufacturing method in which the (200) diffraction intensity ratio is 2.5 or more, when the rolling finishing temperature is less than 600 ° C., the crystal grain size is 1
The rolling finishing temperature is 600 because it may exceed 00μ.
C or higher.

After hot rolling, tempering or annealing heat treatment is necessary in order to increase the (200) diffraction intensity ratio and reduce the strain introduced into the steel sheet by rolling. Since the diffraction intensity ratio becomes low, the upper limit temperature is 950 ° C., but 900 ° C. or less is more preferable to ensure the (200) diffraction intensity ratio.

Next, the reasons for limitation of the present invention will be described. Since C acts as an obstacle to the movement of the domain wall even if it is in a solid solution state or is precipitated as a carbide and reduces the vibration damping property, the lower the C is, the more preferable the upper limit is 0.02%. Si is important as a deoxidizer, so 0.01% or more must be added.
If added in excess of 0.5, it acts as an obstacle to domain wall movement in a solid solution state and reduces vibration damping and toughness, so the upper limit is made 0.50%.

Mn is a solid solution strengthening element that fixes deoxidation and S to fix grain boundary embrittlement, and is an essential element for securing strength. It is necessary to add at least 0.2%.
If it is added in an amount of 5% or more, the damping property is lowered. Therefore M
The amount of n is 0.2 to 2.5%. P and S form non-metallic inclusions in the steel and segregate to impede the movement of the magnetic domain wall to lower the vibration damping property. Therefore, P is set to 0.010% or less and S is set to 0.005% or less.

Al is an important element as a deoxidizing material like Si and Mn, and is an important element for improving the vibration damping property and the strength. It is necessary to secure at least 0.002%, but by excessive addition, it is possible to combine with inclusions such as Al ₂ O ₃ and N to form A.
The upper limit is limited to 0.060% because precipitates such as 1N are generated and the vibration damping property and toughness are deteriorated.

Cr is a ferrite former, which is an element that coarsens the crystal grains by adding it and slightly improves the vibration damping property, but at the same time causes a decrease in toughness and is an expensive element, so it is added as much as possible. Since it is preferable to reduce the amount, the upper limit is limited to less than 0.5%. N is a solid solution state or precipitates as a nitride and acts as an obstacle to the movement of the domain wall to lower the vibration damping property, so that it is preferably as low as possible, and the upper limit is made 0.006%.

Further, Cu, N added as necessary
Although i, Mo, Nb, V, Ti, and B are effective elements for increasing the strength, if added in excess, the vibration damping performance and toughness will deteriorate. The lower limit of strength (tensile strength ≧ 350MP)
The minimum amount of addition required to secure a) was set as the lower limit of each addition amount.

On the other hand, damping performance (loss coefficient η ≧ 0.02)
And the maximum allowable amount for satisfying the lower limit value of the toughness (absorbed energy by V-notch Charpy impact test at 0 ° C. ≧ 100 J) or more was investigated and set as the upper limit of each addition amount.

In addition, Ca, R added as necessary
EM is an element effective in improving toughness, and the minimum addition amount for satisfying the toughness lower limit value of absorbed energy at 0 ° C ≥ 100 J or more is investigated and set as the lower limit, and the vibration damping performance (loss coefficient η
The upper limit was set as the range necessary to secure ≧ 0.02).

Regarding the manufacturing conditions, the heating temperature is 1150 ° C. or lower in order to make the heated austenite grains fine and the (200) diffraction intensity ratio high, and further 1000 ° C. or higher in order to eliminate the temperature deviation in the steel sheet during heating. And

Regarding the rolling conditions, in order to increase the (200) diffraction intensity ratio, it is necessary to roll at 30% or more at 850 ° C. or lower, but if the rolling reduction exceeds 70%, the load on the rolling mill increases, Further, the rolling time becomes long, which causes a cost increase, so the upper limit is set to 70%.

The rolling finishing temperature is 750 ° C. or lower because the rolling temperature is 850 ° C. or lower and 30% or more is rolled, but 600 ° C.
If the temperature is less than 100 μm, the ferrite region may be rolled and the crystal grain size may exceed 100 μm, resulting in a decrease in toughness.
And Furthermore, the finish rolling temperature Ar ₁ -20 ° C. to Ar
_By setting the temperature to ₁ + 50 ° C, the (200) diffraction intensity ratio is further improved and the vibration damping property is further improved.

After hot rolling and cooling to room temperature, (20
0) In order to further improve the diffraction intensity ratio and reduce the strain introduced into the steel sheet by rolling, tempering or annealing heat treatment is required, and heat treatment at 600 ° C. or higher is performed, but the (200) diffraction intensity ratio is The upper limit temperature is set to 900 ° C., because heat treatment weakens it at high temperatures.

[0033]

[Examples] First, a matchmaking alloy having the composition range shown in Table 1 was prepared, and a plate-shaped test piece having an original thickness of 40 mm width and a length of 400 mm was processed from this, and the vibration damping property was measured by a mechanical impedance method. It was Among the alloys shown in Table 1, steels A to E are alloys within the composition range of the present invention, and steels F to N are alloys outside the composition range of the present invention. The various properties of these steels produced under the production conditions shown in Table 2 are also shown in the table. Each steel sheet having a thickness of 6 mm or more was hot-rolled, cooled to room temperature, and then heat-treated. Those having a plate thickness less than that were hot-rolled, wound, and then heat-treated.

Examples 1 to 6 are examples of the present invention, and Examples 7 to 19 are comparative examples. Examples 1, 2, 3, 7 to 13 have a plate thickness of 25 mm,
Example 4 has a plate thickness of 2.5 mm, Examples 5 and 6 have a plate thickness of 50 mm, and Examples 14 to
19 has a plate thickness of 40 mm. The invention example of Example 1 is (200)
Diffraction intensity ratio is 2.5 or more, high intensity (≧ 350MPa),
It has high vibration damping performance (η ≧ 0.015).

In Examples 2 to 6, the rolling finishing temperature was 600 ° C.
As described above, the (200) diffraction intensity ratio is 2.5 or more, the crystal grain size is 100 μ or less, high strength (≧ 350 MPa), high vibration damping performance (η ≧ 0.015) and high toughness (≧ 100 J). )
Having. Since Examples 3 and 4 contain a selective element effective for increasing strength, Examples 5 and 6 have higher strength (≧ 380 MPa).
Has a higher toughness (≧ 120 J) because it contains a selective element effective for increasing the toughness.

Comparative Example 7 has a (200) diffraction intensity ratio of 2.5.
However, the crystal grain size exceeds 100 μ, the C content is high, and the vibration damping performance and toughness are low. Example 8 has a (200) diffraction intensity ratio of 2.5.
As described above, although the crystal grain size is 100 μ or less, Si is high and the vibration damping performance is low. In Example 9, the (200) diffraction intensity ratio is 2.5 or more, and the crystal grain size is 100 μm or less.
Is low and strength is low. Example 10 has a (200) diffraction intensity ratio of 2.5 or more and a crystal grain size of 100 μm or less,
Is high and the damping performance is low.

In Examples 11 and 12, the (200) diffraction intensity ratio is 2.5 or more and the crystal grain size is 100 μ or less.
1 has a high P and Example 12 has a high S, and the vibration damping performance is low. In Example 13, the (200) diffraction intensity ratio is 2.5 or more and the crystal grain size is 100 μm or less, but Cr is high and the toughness is low. In Example 14, the (200) diffraction intensity ratio is 2.5 or more and the crystal grain size is 100 μ or less, but Al is high and the toughness is low. In Example 15, the (200) diffraction intensity ratio is 2.5 or more and the crystal grain size is 100 μ or less, but N is high and the vibration damping performance is low.

The heating temperature is high in Example 16 and 850 in Example 17.
Low rolling reduction below ℃, low (200) diffraction intensity ratio,
If the crystal grain size exceeds 100μ, vibration damping performance and toughness are low. Example 1
No. 8 has a low heat treatment temperature and a low (200) diffraction intensity ratio,
The crystal grain size is 100 μ or less, but the vibration damping performance is low. In Example 19, the heat treatment temperature is high, the (200) diffraction intensity ratio is low, and the crystal grain size is 100 μm or less, but the vibration damping performance is low.

[0039]

[Table 1]

[0040]

[Table 2]

[0041]

[Table 3]

Next, various characteristics of the steels P, Q and R of the alloys in the composition range of the present invention shown in Table 3 are shown together with those produced under the production conditions of the present invention shown in Table 4. Examples 1, 2, 3
Is an example in which the rolling finishing temperature is in a more desirable range.
The plate thickness is all 20 mm. Ar ₁ of the steels P, Q and R are 645 ° C., 650 ° C. and 640 ° C., respectively.

In Examples 1, 2, and 3, the rolling finishing temperature was Ar ₁ +5.
Within the range of 0 ° C. to Ar ₁ -20 ° C., the (200) diffraction intensity ratio is 3.5 or more, and further excellent vibration damping performance (η ≧
0.025) and the rolling finishing temperature is Ar ₁ + 50 ° C.
It has better vibration damping performance than Examples 4 to 6 in which Ar ₁ is not in the range of -20 ° C.

[0044]

[Table 4]

[0045]

[Table 5]

[0046]

[Table 6]

[0047]

According to the present invention, ships, bridges, industrial machines,
Supply of structural materials for construction becomes possible, and the effect on the industrial world is extremely large.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display area F16F 15/02 8312-3J F16F 15/02 Q

Claims (7)

[Claims] 1. By weight%, C: 0.02% or less, Si: 0.01 or more and less than 0.5%, Mn: 0.2 to 2.5%, P: 0.010% or less, S : 0.005% or less, Cr: less than 0.5%, Al: 0.002 to 0.060%, N: 0.006% or less, and the balance Fe and unavoidable impurities, and (200) High-strength steel with excellent vibration damping properties, characterized by a diffraction intensity ratio of 2.5 or more. 2. By weight%, Cu: 0.05 to 2.5%, Ni: 0.05 to 2.5%, Mo: 0.05 to 4.5%, Nb: 0.005 to 0. 2%, V: 0.005 to 0.2%, Ti: 0.005 to 0.1%, B: 0.0003 to 0.005%, at least one or more types being contained. A high-strength steel excellent in vibration damping property according to Item 1. 3. At least one of Ca: 0.001 to 0.05% and REM: 0.001 to 0.10% by weight is contained. High-strength steel with excellent vibration-damping properties. 4. The high-strength steel excellent in vibration damping property according to claim 1, wherein a high toughness is ensured by controlling a crystal grain size to 100 μm or less. 5. A heating temperature of 1000 to 1150 ° C., a rolling reduction of 850 ° C. or less of 30 to 70%, hot rolling at a rolling finishing temperature of 750 ° C. or less, and then cooling to room temperature, 600 to 900. The method for producing a high-strength steel excellent in vibration damping property according to any one of claims 1 to 4, characterized by performing tempering or annealing heat treatment in a temperature range of ° C. 6. A rolling finishing temperature range of 600 to 750 ° C.
The method for producing high-strength steel excellent in vibration damping property according to claim 5, wherein hot rolling is performed. 7. A rolling finishing temperature in a range of Ar ₁ -20 ° C.
The method for producing a high-strength steel excellent in vibration damping property according to claim 5, wherein hot rolling at Ar ₁ + 50 ° C. is performed.