JPH0790498A - Iron-based damping alloy with excellent vibration damping capability - Google Patents

Abstract

(57) [Summary] [Purpose] Tensile strength of 40, which has the strength and toughness required for steel for machine structural use and is relatively inexpensive and has excellent vibration damping characteristics.
We propose a steel for machine structure of 0 MPa or more. [Structure] Fe- (1.0 to 7.0)% Al- (0.0
5 to 1.50)% Cu based damping steel (0.05 to 2
0)% Cr is added.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel for machine structure suitable for use as a member of a structure, particularly for a machine structure having a tensile strength of 400 MPa or more excellent in vibration damping characteristics capable of suppressing vibration and noise. The idea is to propose steel. In recent years, there have been severe vibrations caused by the movement of heavy vehicles such as railway bridges and road bridges for automobiles. The noise that is heard is considered to be a social problem.

As a countermeasure for this, various techniques such as using a sound absorbing material, a sound insulating material or a vibration insulating material, and increasing the rigidity of the structure to avoid resonance have been taken. In general, the vibration that is the noise source is complicated, and it is generally difficult to eliminate the cause. Therefore, a method of giving vibration damping characteristics, that is, vibration damping property to the material itself as a structural member to drastically improve the vibration and noise of the structure has been attracting attention.

[0003]

2. Description of the Related Art Regarding steel materials having the above-mentioned vibration damping property,
Several proposals have already been made. For example,
Japanese Patent Laid-Open No. 60-26813 proposes a method for producing a vibration-proof steel material having a low yield point and coarse grains. In addition, JP-A-52-14431
No. 7 discloses a vibration-proof steel containing 3 to 40 wt% Cr and further added with Ti and Al.
Damped thick steel plate containing 9 wt% Al, and Japanese Patent Publication No. 57-229
Japanese Patent No. 81 discloses a steel material containing 4 to 7 wt% Cr and 3 to 5 wt% Al and having vibration damping properties.

However, any of the steel materials has a relatively low strength and cannot be used as a structural member. In addition, there are problems that the vibration damping property is not sufficient and that the alloy component is added in a large amount and is expensive.

[0005]

[Problems to be Solved by the Invention] Tensile material that can be mass-produced, has high vibration damping property, has strength and toughness necessary for steel for machine structural use, and is relatively inexpensive and has excellent vibration damping characteristics. It is an object of the present invention to propose a mechanical structural steel having a strength of 400 MPa or more.

[0006]

[Means for Solving the Problem] In the case of ferromagnetic steel,
Strain (magnetostriction) in the crystal lattice in response to the alignment of magnetic spins
Due to this effect, the inside is divided into magnetic domains. When external force (vibration) is applied to such steel,
The domain wall moves due to the interaction with the magnetostriction. Then, an eddy current is generated so as to cancel the movement of the domain wall, that is, the change in the magnetization, which occurs inside the ferromagnetic body, and the eddy current causes distortion through magnetostriction. Since the phase of this strain is delayed with respect to the external force, a vibration damping characteristic appears due to so-called magneto-dynamic hysteresis type internal friction. Regarding this, for example, it is known that pure iron has excellent vibration damping properties.

However, pure iron cannot be applied as a structural member because of its low strength and toughness. On the other hand, the present inventors previously added Cu to steel having a substantially pure iron composition in which the amount of Mn was reduced to 0.08 wt% or less, and further added Al to 1.0
By adding ~ 7.0%, while maintaining high vibration damping ability,
Moreover, we proposed a steel sheet having both strength and toughness as a structural steel material (see Japanese Patent Laid-Open No. 4-13847).

[0008]

Means for Solving the Problems As a result of various studies to improve the strength and vibration damping capacity of the above steel, the present inventors have found that 0.05 to 20 wt% Cr is added to the above steel. Therefore, it was found that the strength can be further improved without impairing the vibration damping property. Based on the above findings, the present invention, which has further improved mechanical properties as compared with the steel of the prior application, has C: 0.02 wt% or less, Si: 0.02 wt% or less, Mn: 0.08 wt% or less, Cu: 0.05-
1.50wt%, Cr: 0.05-20wt%, Al: 1.0-7.0wt%, N: 0.0
040 wt% or less, the balance is Fe and inevitable impurities excellent vibration damping characteristics mechanical structural steel, the present invention, C: 0.02 wt% or less, Si: 0.02 wt% or less, M
n: 0.08 wt% or less, Ni: 0.05-1.50 wt%, Cu: 0.05-1.50
wt%, Cr: 0.05-20 wt%, Al: 1.0-7.0 wt%, N: 0.0040
A mechanical structural steel containing less than wt% and the balance being Fe and unavoidable impurities with excellent vibration damping characteristics.

[0009]

In the mechanical structural steel of the present invention having excellent vibration damping characteristics, strength and toughness, the reason why the component composition is limited to the above range will be described first. C: 0.02 wt% or less C is contained as a strengthening component in ordinary steel, but in this invention steel, since the strengthening action due to precipitation of Cu is utilized,
No amount as a reinforcing ingredient is required. Rather, the C content is 0.02
When it exceeds wt%, the vibration damping property deteriorates, so it was limited to 0.02 wt% or less. Si: 0.02 wt% or less Since the addition of Si in excess of 0.02 wt% to the Mn-reduced steel deteriorates the damping property, 0.02 wt% was set as the upper limit. Mn: 0.08% or less Mn adversely affects toughness when strengthened by addition of Cu, so the lower the content, the better.The upper limit of the content is 0.08wt%, so it is limited to 0.08wt% or less. did. Cu: 0.05-1.50% Cu is precipitated as fine ε-Cu by aging treatment,
It is a component that strengthens steel, and is used for steel with a reduced Mn content.
By including Cu, it is possible to achieve both strength and toughness without impairing the vibration damping property. Therefore, it is an essential component in this invention, but if the Cu content is less than 0.05%, its effect is poor, and if it exceeds 1.50%, hot cracking may occur, so the range of 0.05-1.50% is required. And Cr: 0.05 to 20 wt% Cr has the effect of increasing the strength without deteriorating the internal friction value, and is an important element that improves the corrosion resistance of steel materials and is essential to the present invention, but less than 0.05 wt% The effect is not obtained with addition, while the effect is saturated if added in excess of 20 wt% and the economic efficiency is impaired, so the range was made 0.05 to 20 wt%. Al: 1.0-7.0% Al reduces Mn to 0.08% or less, and improves vibration damping characteristics in steel with almost pure iron composition, but its content is 1.
If the content is less than 0%, the effect will not be obtained.On the other hand, if the content exceeds 7.0%, the toughness of the weld will deteriorate, so the content is 1.0-7.0%.
And the range. N: 0.0040% or less N is preferably low in content from the viewpoint of vibration damping property and toughness, and the allowable upper limit is 0.0040% or less.

The steel of the present invention contains Ni in an amount of 0.05 to 1.50% in addition to the above components in the second invention. Ni: 0.05 to 1.50 wt% Ni can suppress the tendency of hot cracking due to the addition of Cu without impairing the vibration damping property. If the Ni content is less than 0.05%, the effect is poor, while if it exceeds 1.50%, it is not economical. Therefore, the Ni content is 0.05 to 1.50.
The range is%.

In addition to the above components, P and S of 0.01% and 0.005 wt% are acceptable as impurity components in the present invention. The P content deteriorates with the increase of its content, but 0.01% is acceptable, so the upper limit is 0.01%. S, like P, is a component that is unfavorable to vibration damping,
If the content exceeds 0.005%, the vibration damping property is particularly deteriorated. Therefore, the upper limit of S content is 0.005%.

The material of the present invention can be formed into a thick steel plate by ordinary melting, casting and rolling. Further, not only thick steel plates but also thin steel plates, shaped steels, steel bars, wire rods and the like can be used. In addition, it is preferable to perform normal tempering for the precipitation of Cu.

[0013]

[Example] Steels having various compositional compositions shown in Table 1 were melted and cast according to a conventional method, and further subjected to ordinary hot rolling.
mm, annealed at 850 ℃ ~ 1000 ℃, and further
As a Cu precipitation aging treatment, heat treatment was performed at 575 ° C for 1 hour. The mechanical properties of the obtained product were measured by collecting a round bar tensile test piece from the central portion of the steel plate. The damping characteristic (Q ^-1 ) was measured by a mechanical impedance method by collecting a 1.5 mm-thick strip test piece from the center of the steel sheet. The larger the value of Q ^{-1, the} better the vibration damping characteristics.

In Table 1, symbols A to E are steel plates having the composition of the steel of the present invention. On the other hand, symbols F to J are comparative examples, and Cr is out of the range of Cr in the present invention. The symbol K indicates SS400 steel as the conventional steel.
The tensile properties and internal friction Q ^-1 of the base materials of these steel sheets were measured, and the obtained results are also shown in Table 1.

[0015]

[Table 1]

As is clear from the table, all of the steels A to E in the composition range of the present invention satisfy the tensile strength of 400 MPa or more required as a structural steel sheet. In addition, the internal friction value is far superior to the conventional SS400 steel, and the vibration damping property is improved. Further, the steels A to E of the present invention have higher strength as compared with the comparative examples, and the internal friction value is JP-A-4.
-13847 shows the same value as the steel of the prior application,
It can be seen that it has both high strength and good vibration damping properties.

[0017]

EFFECTS OF THE INVENTION The mechanical structural steel excellent in vibration damping characteristics of the present invention is a steel having a composition of almost pure iron in which the amount of Mn is reduced to 0.08% or less, Cu is added, and Al is 1.0 to 7.0%. By adding 0.05 to 20% of Cr to the low N steel with added vibration damping properties, sufficient tensile strength of 400 MPa as a structural material can be obtained.
It has the industrially useful property of having both the above high strength and good vibration damping performance.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasushi Morikage 1 Kawasaki-cho, Chuo-ku, Chiba-shi, Chiba Kawasaki Steel Corporation Technical Research Division (72) Inventor Shinichi Amano Kawasaki-cho, Chiba-shi, Chiba No. 1 Kawasaki Steel Co., Ltd. Technical Research Division

Claims (2)

[Claims] 1. C: 0.02 wt% or less, Si: 0.02 wt% or less, M
n: 0.08 wt% or less, Cu: 0.05 to 1.50 wt%, Cr: 0.05 to 20w
t%, Al: 1.0 to 7.0 wt%, N: 0.0040 wt% or less,
The balance consists of Fe and unavoidable impurities, and is a mechanical structural steel with excellent vibration damping characteristics. 2. C: 0.02 wt% or less, Si: 0.02 wt% or less, Mn:
0.08 wt% or less, Ni: 0.05 to 1.50 wt%, Cu: 0.05 to 1.50 w
t%, Cr: 0.05 to 20 wt%, Al: 1.0 to 7.0 wt%, N: 0.0040w
Steel for machine structural use that contains less than t% and the balance is Fe and unavoidable impurities with excellent vibration damping characteristics.