JPH05271877A - High strength and high thermal expansion fe-ni alloy and its manufacture - Google Patents

Abstract

PURPOSE:To obtain a high strength and high thermal expansion Fe-Ni alloy not only having a high thermal expansion coefficient but also having strength higher than that of the conventional one as well as useful for the miniaturizing and thinning of bimetals and temp. compensating parts. CONSTITUTION:The objective high strength and high thermal expansion Fe-Ni alloy contains, by weight, <=0.05% C, <=0.03% N, 0.01 to 2.0% Si, 0.01 to 3.0% Mn, 25 to 45% Ni, 0.01 to l.0% Cr, 1.0 to 5.0% Ti and <=0.01% S or furthermore contains total 0.1 to 3.0% of one or >= two kinds among Al, V, Zr, Nb, Ta, Hf and Be, and the balance Fe with inevitable impurities; and the manufacture of the objective high strength and high thermal expansion Fe-Ni alloy in which the alloy having this compsn. is subjected to plastic working, heat treatment or the like, is thereafter subjected to solid solution treatment at 900 to 1100 deg.C and is subjected to aging treatment at 500 to 800 deg.C is obtd.

Description

Detailed Description of the Invention

[0001]

INDUSTRIAL APPLICABILITY The present invention has a large average coefficient of thermal expansion and a high strength such as hardness and is suitable for use in forming a member having a bimetal function, and can be widely used in electric products. , A high strength and high thermal expansion Fe-Ni alloy and a method for producing the same.

[0002]

2. Description of the Related Art A high thermal expansion alloy constitutes a composite member by mechanically welding or welding with an Fe-Ni-based so-called amber type low thermal expansion alloy, ordinary steel, stainless steel or the like,
Utilizing its bimetal function, it is widely used in electrical products as temperature sensors and temperature compensation components.

Conventionally, in a bimetal, a 21% Ni-6% Cr-Fe alloy or 22% is usually used as a high thermal expansion material.
A Ni-3% Cr-Fe alloy or the like is used, and the low thermal expansion material is amber (36% Ni-Fe). However, the high thermal expansion material has a hardness of 100 to 130 Hv and a 0.2% proof stress of 20 to 2 in the solution treatment state.
It was about 5 kg / mm ² , and sufficient strength could not be obtained.

The above-mentioned amber and nickel steel having a similar composition are known as amber-type alloys.
Due to its low thermal expansion property, it is widely used as a material for LNG (liquefied natural gas) tanks, which have a large temperature difference between the time of use and normal temperature, and a material for Maybren tanks of LNG marine transportation ships. An example of them is Fe-, which has excellent rust resistance.
As a Ni-based low thermal expansion amber alloy, Ni: 30 to 4
5%, C: 0.04%, Si: 0.05 to 0.25
%, Mn: 0.10 to 0.40%, and Co: 0.0
1 to 1.50%, if necessary, Ca: 0.005
~ 0.100%, Cr: 0.50 to 3.00%, Cu:
0.50 to 3.00%, Ti: 0.01 to 0.50%,
Zr: It is known that one or more of 0.01 to 0.50% is contained, and the balance consists of Fe and inevitable impurities (JP-A-57-207160).

Recently, there has been a demand for downsizing and thinning of temperature sensors and temperature compensating components by downsizing and downsizing of communication machines, electrical products, and precision measuring machines. In order to meet this requirement, in order to function as this kind of material up to a temperature of 100 ° C. or higher, it is essential that one material of the composite material has a high coefficient of thermal expansion and high strength at the same time. Become.

[0006]

SUMMARY OF THE INVENTION The present invention aims to provide an Fe-Ni alloy having a high coefficient of thermal expansion and high strength, and a method for producing the same, in accordance with the conventional demands of the industry. Therefore, from the conventional usage examples, at least 30 to 100 ° C that can sufficiently satisfy the usage conditions.
To provide an Fe-Ni alloy having an average thermal expansion coefficient of 10 × 10 ⁻⁶ / ° C. or more and a hardness of 260 Hv or more in a temperature range of 30 to 450 ° C., and a manufacturing method thereof. It is intended.

[0007]

The inventors of the present invention basically use a conventional low thermal expansion amber alloy (Fe-36Ni, thermal expansion coefficient of 1.5 × 10 ⁻⁶ / ° C., hardness of 130 to 150 Hv). As a result of detailed investigation on the effect of various added elements and heat treatment on the composition, the above-mentioned JP-A-57-2071
In the amber type alloy disclosed in Japanese Patent No. 60, when Ti is added in a specific amount in order to lower the coefficient of thermal expansion, a large amount that is not included in the conventional amber alloy is added, and the coefficient of thermal expansion is unexpectedly increased. It was discovered that an alloy with high strength and high strength can be obtained, and based on the findings, research was advanced to arrive at the present invention. In the production of the alloy, plastic working and heat treatment are performed until a desired shape is obtained, and after the final plastic working, a solution treatment in a temperature range of 900 to 1100 ° C. has a considerably high strength. You get something. Further, it was found that a Fe-Ni alloy having higher strength can be obtained by subjecting the solution-treated solution to an aging treatment at 500 to 800 ° C.

That is, the present invention provides the following means.
The above objective was achieved. (1) In% by weight C: 0.05% or less N: 0.03% or less Si: 0.01 to 2.0% Mn: 0.01 to 3.0% Ni: 25 to 45% Cr: 0 0.01 to 1.0% Ti: 1.0 to 5.0% S: 0.01% or less, a high strength and high thermal expansion Fe-Ni alloy containing the balance Fe and inevitable impurities. (2) Further, in weight%, Al ≦ 1.5%, V ≦ 2.
0%, Zr ≦ 0.5%, Nb ≦ 3.0%, Ta ≦ 3.0
%, Hf ≦ 3.0%, Be ≦ 2.0%, and one or more kinds are contained in a total amount of 0.1 to 3.0%, the high strength according to the above item (1). High thermal expansion Fe-Ni alloy. (3) In% by weight C: 0.05% or less N: 0.03% or less Si: 0.01 to 2.0% Mn: 0.01 to 3.0% Ni: 25 to 45% Cr: 0 0.01 to 1.0% Ti: 1.0 to 5.0% B: 0.0005 to 0.01% S: 0.01% or less with the balance being Fe and inevitable impurities Expanded Fe-Ni alloy. (4) Further, in weight%, Al ≦ 1.5% and V ≦ 2.
0%, Zr ≦ 0.5%, Nb ≦ 3.0%, Ta ≦ 3.0
%, Hf ≦ 3.0%, Be ≦ 2.0%, and one or more of them is contained in a total amount of 0.1 to 3.0%. High thermal expansion Fe-Ni alloy. (5) In% by weight C: 0.05% or less N: 0.03% or less Si: 0.01 to 2.0% Mn: 0.01 to 3.0% Ni: 25 to 45% Cr: 0 0.01 to 1.0% Ti: 1.0 to 5.0% S: 0.01% or less, or B: 0.0005 to 0.
01% or any of these, and further by weight%, Al ≦ 1.5%, V ≦ 2.0%, Zr ≦
0.5%, Nb ≦ 3.0%, Ta ≦ 3.0%, Hf ≦
3.0%, Be ≦ 2.0%, one or more of 0.1% to 3.0% in total, with the balance being Fe and unavoidable impurities, the desired shape 900 ~ 11 after the final plastic working
Solid solution treatment is performed in the temperature range of 00 ° C., and 500 to 8
A method for producing a high-strength and high-thermal expansion Fe-Ni alloy, which comprises performing an aging treatment in a temperature range of 00 ° C.

The Fe-Ni alloy of the present invention is 30-100
Average thermal expansion coefficient in the temperature range of ℃ is 10 × 10 ^-6 /
It has a high thermal expansion of 260 Hv or higher and a high hardness, but it has a B value as in the third invention (the invention of claim 3).
If it contains Al, the hot workability is improved, and if an additional element such as Al is further contained as in the second invention (the invention of claim 2) or the fourth invention (the invention of claim 4), the strength is further improved. Becomes higher. Further, the alloy of the present invention, a good alloy structure can be obtained by performing up to the solution treatment, the strength is increased, but an alloy having a remarkably high strength if the aging treatment is further performed after the solution treatment. Can be obtained, which has a hardness of 300 Hv or more.

The conditions for the solution treatment are 900 to 11
Although it is in the temperature range of 00 ° C, if it is less than 900 ° C, the solid solution strengthening element cannot be sufficiently dissolved to form a solid solution at 1100 ° C.
If it exceeds, the crystal grains are coarsened and the strength is lowered.
Moreover, the aging treatment condition is a temperature range of 500 to 800 ° C., but if it is less than 500 ° C., age hardening does not occur, and
If it exceeds ℃, the coefficient of thermal expansion decreases.

[0011]

The reason why the composition of the alloy of the present invention is determined as described above is as follows. C: 0.05% or less; C contributes to solid solution strengthening and material hardening by work hardening. If it exceeds 0.05%, the electrical resistance is increased to deteriorate the conductivity, and a large amount of carbide is deposited to deteriorate the hot workability, toughness and punchability. Therefore, the upper limit of the content is set to 0.05%.

[0012] N: 0.03% or less; When the amount of N is large, a large amount of nitride precipitates, which deteriorates the toughness and punchability. Further, N is an alloy based on B addition,
Since it is easily combined with B to form BN, the amount of effective B decreases, and the formed BN adversely affects when the content in the alloy increases. If the N content exceeds 0.03%, the above-mentioned adverse effect becomes large, so the upper limit is set to 0.0
It was set to 3%.

Si: 0.01 to 2.0%; Si needs 0.01% or more as a deoxidizing agent in refining an alloy, but if it exceeds 2.0%, hot workability is present. Is deteriorated, so the range is limited to 0.01 to 2.0%. Mn: 0.01 to 3.0%; Mn can be solid solution strengthened, and when refining the alloy, 0.01% or more is required as a deoxidizing agent, but even if it exceeds 3.0% There is no change in deoxidizing effect, which is a cost disadvantage. Further, if the content of Mn is increased, there is a manufacturing problem that the hot workability at the time of manufacturing is essentially lowered, so 0.01 to 0.01
It is limited to the range of 3.0%.

Ni: 25-45%; When Ni is less than 25%, martensite is formed even in the annealed state, and magnetic properties, thermal expansion, strength, and other physical properties are impaired, which is not preferable. % Or more is required. However, if Ni exceeds 45%, the toughness deteriorates, the saturation magnetic flux density and the electric resistance decrease, which is disadvantageous in terms of cost. Therefore, the upper limit is 45%.

Cr: 0.01-1.0%; Cr is 0.2
% It is an element that significantly lowers the proof stress and improves the press formability, and it is necessary to contain 0.01% or more in order to produce the effect. However, 0.2% above 1%
The yield strength is significantly reduced. Ti: 1.0 to 5.0%; Ti is an element that characterizes the present alloy, and imparts high strength due to age hardening to the present alloy,
Further, addition of at least 1.0% is necessary to impart high thermal expansion characteristics. However, if the content exceeds 5.0%, the toughness and weldability are deteriorated and the cost is increased, so the content is limited to the range of 1.0 to 5.0%. It is preferably 1.0 to 4.0%.

B: 0.0005 to 0.01%; used to improve hot workability, but if it exceeds 0.01%, a large amount of boron compound is precipitated, resulting in hot workability and toughness of material. Both deteriorate, so the upper limit is made 0.01%. S: 0.01% or less; If S exceeds 0.01%, hot workability is impaired, so the upper limit was made 0.01%.

Al ≦ 1.5%, V ≦ 2.0%, Zr ≦
0.5%, Nb ≦ 3.0%, Ta ≦ 3.0%, Hf ≦
3.0%, Be ≦ 2.0%, and one or more of them in total amount of 0.1 to 3.0%; these elements are the strength of the alloy due to their solid solution strengthening action and age hardening. And further helps increase the coefficient of thermal expansion. On the other hand, if the amount is too large, the toughness deteriorates.

Particularly, of these, the addition of Nb alone or the combined addition of Nb and Zr makes the grain size extremely fine, maintains high toughness and punchability, and further hardens by solid solution strengthening in the annealed state. Is increased by 25% or more. Further, due to them, the dislocation density is increased by rolling and the strength is further increased by work hardening. By subjecting the alloy of the present invention to aging treatment, the hardness, tensile strength, elastic limit, and fatigue strength can be effectively improved without impairing the high thermal expansion property.

[0019]

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited to this embodiment. Example Raw materials were blended so as to have the composition shown in Table 1 below, and each blend was heated and melted in an air induction furnace at 10 kg to obtain an ingot.
A hot forging process is performed at 0 ° C., then an annealing process of heating at 950 ° C. and then slowly cooling and a cold rolling process at a reduction rate of 90% are repeated, and a final cold rolling process is performed at a reduction rate of 80%. The rolling process was completed to obtain a plate-shaped body having a thickness of 0.1 mm. Then, after performing a solution treatment at each temperature for 1 hour, the solution was rapidly cooled, and an aging treatment at each temperature for 1 hour was performed. The conditions of the solution treatment and the aging treatment are shown in Table 2.

A thermal expansion test was conducted on these plate-like bodies, the thermal expansion coefficient was measured in the temperature range from room temperature to 300 ° C., an average thermal expansion coefficient of 30 to 100 ° C. was obtained, and a tensile test was conducted to obtain a value of 0. The 2% proof stress was measured, and the hardness (Vickers hardness number) was measured by the hardness test. The measurement results are shown in Table 3.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

[Table 3]

Table 1 shows the components and composition ratios of Examples of the present invention alloy and Comparative Example of the comparative alloy, and Table 2 shows the heat treatment conditions thereof. In addition, Table 3 shows the thermal expansion coefficient and mechanical properties of the examples of the alloy of the present invention and the comparative alloy shown in Table 1. As is clear from Table 3, the alloy of the present invention has a high coefficient of thermal expansion, high hardness and proof stress, and can be said to have high strength in combination with high thermal expansion.

[0025]

As can be seen from the examples, the alloy of the present invention has high thermal expansion and high strength. In particular, those subjected to aging treatment after solution treatment,
It has high hardness of 300 Hv or more, high strength, and 10 × in the temperature range of 30 to 100 ° C.
It is a high thermal expansion alloy having a high thermal expansion coefficient of 10 ^-6 / ° C or higher. As described above, the Fe-Ni alloy of the present invention or the Fe-Ni alloy obtained by the manufacturing method of the present invention is an alloy having high strength and high thermal expansion which has never been obtained, and therefore, it is used for a temperature sensor, a temperature compensating component or the like. Suitable for

Front page continued (72) Inventor Takeya Toge 4-2 Kojima-cho, Kawasaki-ku, Kawasaki-shi, Kanagawa Nihon Metallurgical Industry Co., Ltd. Technical Research Center

Claims (5)

[Claims] 1. C .: 0.05% or less N: 0.03% or less Si: 0.01 to 2.0% Mn: 0.01 to 3.0% Ni: 25 to 45% Cr : 0.01 to 1.0% Ti: 1.0 to 5.0% S: 0.01% or less, and a high strength and high thermal expansion Fe-Ni alloy containing the balance of Fe and inevitable impurities. 2. Further, in weight%, Al ≦ 1.5%, V
≦ 2.0%, Zr ≦ 0.5%, Nb ≦ 3.0%, Ta ≦
3.0%, Hf ≦ 3.0%, Be ≦ 2.0%, 1
The high-strength and high-thermal expansion Fe-Ni alloy according to claim 1, characterized in that the total content of one or more kinds is 0.1 to 3.0%. 3. In% by weight C: 0.05% or less N: 0.03% or less Si: 0.01 to 2.0% Mn: 0.01 to 3.0% Ni: 25 to 45% Cr : 0.01 to 1.0% Ti: 1.0 to 5.0% B: 0.0005 to 0.01% S: 0.01% or less, with the balance being Fe and inevitable impurities. High strength and high thermal expansion Fe-Ni alloy. 4. Further, in weight%, Al ≦ 1.5%, V
≦ 2.0%, Zr ≦ 0.5%, Nb ≦ 3.0%, Ta ≦
3.0%, Hf ≦ 3.0%, Be ≦ 2.0%, 1
The high-strength and high-thermal-expansion Fe-Ni alloy according to claim 3, which contains 0.1 to 3.0% of the total amount of one or more kinds. 5. In% by weight C: 0.05% or less N: 0.03% or less Si: 0.01 to 2.0% Mn: 0.01 to 3.0% Ni: 25 to 45% Cr : 0.01-1.0% Ti: 1.0-5.0% S: 0.01% or less, or in addition to that, B: 0.0005-0.
01% or any of these, and further by weight%, Al ≦ 1.5%, V ≦ 2.0%, Zr ≦
0.5%, Nb ≦ 3.0%, Ta ≦ 3.0%, Hf ≦
3.0%, Be ≦ 2.0%, one or more of 0.1% to 3.0% in total, with the balance being Fe and unavoidable impurities, the desired shape 900 ~ 11 after the final plastic working
Solid solution treatment is performed in the temperature range of 00 ° C., and 500 to 8
A method for producing a high-strength and high-thermal expansion Fe-Ni alloy, which comprises performing an aging treatment in a temperature range of 00 ° C.