JPH04365839A - Ferromagnetic high damping alloy with high toughness - Google Patents

Abstract

PURPOSE:To obtain a high damping alloy for structural material simultaneously having three satisfactory characteristics of strength, toughness, and damping property. CONSTITUTION:A high-toughness ferromagnetic high damping alloy which has a composition consisting of, by weight ratio, #0.05% C, 0.05-0.1% Si, 0.05-0.1% Mn, 1-3% Mo, 2-6% W, further Cr and La under the restriction of 9-15% Cr and 0.01-0.04% La while holding the balance satisfying the relations in 0>=0.001XCr-La, and the balance Fe with inevitable impurities is produced. By this method, the alloy having >=50kgf/mm<2> tensile strength, >=0.02 loss factor, and >=30kgf.m 0 deg.C Charpy absorbed energy can be provided.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] The present invention relates to a high Cr-based ferrite alloy that satisfies the strength and toughness required as a structural material for large cruise ships and industrial machinery, and at the same time has high vibration damping properties.

0002

BACKGROUND OF THE INVENTION Recently, structural materials for luxury ultra-large cruise ships and industrial machinery are required to have added values such as comfort and vibration damping properties in addition to strength and toughness. In other words, structural materials for luxury cruise ships that minimize vibrations caused by waves and engine operation during sea operations, allowing for comfortable navigation, and structural materials that can control as much as possible the large vibrations caused by large, high-output industrial machinery. There is a strong need for

0003

[Problems to be Solved by the Invention] Conventionally, materials used for members intended for vibration damping have been disclosed in Japanese Patent Application Laid-Open No. 52-632.
Examples include ferromagnetic high Cr vibration damping alloys described in Japanese Patent Application Laid-Open No. 52-10820. However, although these alloys have sufficient vibration damping properties, they basically cannot be used as structural materials because they lack the strength and toughness that are required as structural materials.

0004

[Means for Solving the Problems] The gist of the present invention is that, in terms of weight ratio, C: 0.05% or less, Si: 0.05 to 0.1%,
Mn: 0.05~0.1%, Mo: 1~3%, W: 2~
6%, and Cr and La: 9 to 15%;
La: 0≧0.001 under the limit of 0.01-0.04%
It is a high toughness ferromagnetic vibration damping alloy consisting of xCr-La with the balance being Fe and unavoidable impurities.

[0005]

[Function] The present invention adds Mo and W, which are solid solution strengthening elements, to a ferromagnetic type high Cr ferrite alloy, and also removes coarse inclusions such as Cr-based inclusions, which are factors that degrade toughness, by adding La. By controlling the inclusions, we succeeded in obtaining an alloy that has excellent vibration damping properties as well as high strength and toughness.

[0006] The present invention uses a high Cr ferrite alloy as a basic component system in order to obtain high vibration damping characteristics caused by hysteresis due to irreversible motion of domain wall movement under the action of alternating stress due to vibration, and uses a high Cr ferrite alloy as a basic component system, and uses a solid solution strengthening mechanism. Adding Mo and W as the elements that can most effectively improve the strength of the ferrite phase, and controlling coarse inclusions such as Cr-based inclusions, which are factors that degrade toughness, into fine inclusions by adding La to improve toughness. let

The alloy of the present invention is based on high Cr in order to improve the magnetic properties of the matrix, but there is an upper limit because excessive addition leads to precipitation of intermetallic compounds, hinders domain wall movement, and greatly impairs vibration damping properties. On the other hand, Mo and W are added for the purpose of improving strength, but excessive addition leads to fine dispersion of precipitates and inhibits magnetic domain movement.

Next, the reasons for the limitations of the present invention will be explained.

First, C acts as an obstacle to domain wall movement even when it is in a solid solution state or when it is combined with Mo and W and precipitated as fine carbides, reducing vibration damping properties, so the upper limit is set at 0.05.
%.

[0010]Since Si is important as a deoxidizing agent, the minimum
．． 0.5% is necessary, but if it is added in excess of 0.1%, the effect of hindering domain wall movement becomes significant, so the upper limit is set to 0.1%.
shall be.

[0011] It is necessary to ensure a minimum amount of Mn of 0.05% for deoxidation, but if it is added in excess of 0.1%, vibration damping properties will deteriorate. Therefore, the amount of Mn is set to 0.05 to 0.1%.

Mo and W are important as solid solution strengthening elements. A minimum of 1% and 2%, respectively, is required, but addition of more than 3% and 6%, respectively, leads to fine dispersion of precipitates, significantly impairing vibration damping properties.

Cr is an important element in the present invention. Cr is an element for obtaining ferromagnetic ferrite, and is important for improving the basic magnetism of the matrix and as a ferrite former. Therefore, a minimum content of 9% is required, but if it exceeds 15%, the σ phase harmful to domain wall movement is precipitated, resulting in a decrease in vibration damping properties, as well as the formation of coarse inclusions, resulting in a decrease in toughness. Therefore, the Cr amount is set to 9 to 15%.

Next, La, which is the most important element in the present invention,
has the function of forming a composite compound of S and O to suppress the formation of inclusions such as CrS, thereby significantly improving toughness. Therefore, it is necessary to add at least 0.01%. However, since excessive addition causes coarsening of inclusions, the upper limit of addition is 0.04%. Furthermore, La
In order to offset the toughness reducing effect of Cr, it must be added in balance with the amount of Cr added. Therefore, Cr and La
When considering the addition balance of 0≧0.001×C
It has been found that good toughness can be obtained if r-La is satisfied. Therefore, La must be added so as to simultaneously satisfy the addition range of 0.01 to 0.04% and the relationship of 0≧0.001×Cr-La.

[0015]

[Example] First, a sample gold having the composition range shown in Table 1 was prepared, and a plate-shaped specimen of 20 mm thickness x 40 mm width x 200 mm length was processed from the sample, and vibration damping properties were measured using the mechanical impedance method. . Furthermore, a tensile test and a Charpy impact test at room temperature were also conducted.

Among the alloys shown in Table 1, No. 1~No. 4
is an alloy within the composition range of the present invention, and No. 5~No. 1
No. 9 is a comparative example alloy outside the composition range of the present invention.

Comparative example alloy No. 5, No. 6 and no.
7, each of C, Si and Mn exceeds the upper limit of the present invention.

Comparative example alloy No. No. 8 has Mo less than the lower limit of the present invention. 9 exceeds the upper limit of the present invention.

Comparative example alloy No. No. 10 has W less than the lower limit of the present invention. 11 exceeds the upper limit of the present invention.

Comparative example alloy No. No. 12 has Cr below the lower limit of the present invention. 13 exceeds the upper limit of the present invention.

Comparative example alloy No. 14 and no. 15 is L
a is less than the lower limit of the present invention, No. 16 and no. 17 exceeds the upper limit of the present invention.

Comparative example alloy No. 18 and no. 19 is L
Although a alone is within the scope of the present invention, the balance with Cr is outside the scope of the present invention.

Comparative example alloy No. 5, No. 6 and no.
No. 7 has low vibration damping properties due to the inhibitory effect on domain wall motion due to the excessive addition of C, Si, and Mn, respectively.

Comparative example alloy No. 8 and no. No. 10 has low strength because Mo and W are below the lower limit of the present invention.

Comparative example alloy No. 9 and no. In No. 11, Mo and W each exceed the upper limit of the present invention, so the strength is sufficient but the damping property is low.

Comparative example alloy No. No. 12 has low vibration damping properties because the Cr content is below the lower limit of the present invention; 13 is Cr
Damping properties and toughness are low due to excess σ phase precipitation.

Comparative example alloy No. 14 and no. No. 15 has low toughness because La is below the lower limit of the present invention and the addition balance with Cr is not satisfied. 16
and no. In No. 17, since La exceeds the upper limit of the present invention, inclusions become coarse and the toughness is low.

Comparative example alloy No. 18 and no. 19 is C
Toughness is low because the addition balance of r and La is inappropriate.

In contrast, alloy No. 1 of the present invention example. 1~N
o. 4 shows sufficient characteristics in both vibration damping properties and strength.

[0030]

[Table 1]

[0031]

[Effects of the Invention] The present invention makes it possible to supply structural materials for ships and industrial machinery that require strength, toughness, and vibration damping properties at the same time, and has an extremely large effect on the industrial world.

Claims (2)

[Claims] Claim 1: In terms of weight ratio, C: 0.05% or less, Si: 0.05-0.1%, Mn: 0.05-0.1%, Mo: 1-3%, W: 2-2%. 6%, and contains Cr and La in a balance such that 0≧0.001×Cr-La under the limits of Cr: 9 to 15% and La: 0.01 to 0.04%, and the balance is Fe. A high-toughness ferromagnetic damping alloy consisting of unavoidable impurities. 2. The alloy according to claim 1, which has a loss coefficient of 0.02 or more, a tensile strength of 50 kgf/mm2 or more, and a Charpy impact absorption energy of 30 kgf/mm or more at 0°C.