JP2017088949A - Copper alloy material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper alloy material having stable characteristic features and an excellent use-life even when used under a high temperature environment of 500°C or higher.SOLUTION: The copper alloy material has a composition comprising not less than 0.3 mass% and not greater than 0.5 mass% of Cr, not less than 0.01 mass% and not greater than 0.15 mass% of Zr, the balance of Cu and unavoidable impurities where the average crystal grain size is not less than 0.1 mm and not greater than 2.0 mm, and the standard deviation of crystal grain sizes is not greater than 0.6.SELECTED DRAWING: None

Description

  The present invention relates to a copper alloy material suitable for a member used in a high temperature environment such as a casting mold material or a welding member such as a contact tip.

Conventionally, Cu—Cr—Zr alloys such as C18150 have excellent heat resistance and electrical conductivity, and therefore, as shown in Patent Documents 1 and 2, a molding material for casting or welding in which the use environment becomes high temperature. It is used as a material for construction materials.
Such a Cu-Cr-Zr-based alloy is usually subjected to plastic working on a Cu-Cr-Zr-based alloy ingot, for example, a holding temperature of 950 to 1050 ° C and a holding time of 0.5 to 1.5 hours. It is manufactured by a manufacturing process in which a solution treatment and an aging treatment with a holding temperature of 400 to 500 ° C. and a holding time of 2 to 4 hours are performed, and finally finished into a predetermined shape by machining.
Strength and electrical conductivity are improved by solid solution of Cr and Zr in the matrix of Cu by solution treatment and fine dispersion of Cr and Zr precipitates by aging treatment.

JP 62-097748 A JP 05-339688 A

By the way, the above-described Cu—Cr—Zr alloy has excellent heat resistance, but when exposed to a use environment having a peak temperature of 500 ° C. or higher, reprecipitation of precipitates begins, and accordingly. As a result, the strength and electrical conductivity are lowered, and coarsening of crystal grains may occur.
When the coarsening of crystal grains occurs, the propagation speed of cracks may increase and the product life may be shortened. Further, there is a problem that mechanical properties such as strength and elongation are remarkably deteriorated due to the occurrence of coarsening of crystal grains locally.

  The present invention has been made in view of the circumstances described above, and is a copper alloy material that has stable characteristics and excellent service life even when used in a high temperature environment of 500 ° C. or higher. The purpose is to provide.

  In order to solve the above-mentioned problems, the copper alloy material of the present invention contains Cr in the range of 0.3 mass% to less than 0.5 mass%, Zr in the range of 0.01 mass% to 0.15 mass%, with the balance being Cu and inevitable. It has a composition composed of impurities, has an average crystal grain size in the range of 0.1 mm to 2.0 mm, and has a standard deviation of crystal grain size of 0.6 or less.

In the copper alloy material of this structure, Cr is 0.3 mass% or more and less than 0.5 mass%, Zr is 0.01 mass% or more and 0.15 mass% or less, and the balance is composed of Cu and inevitable impurities. Therefore, strength (hardness) and electrical conductivity can be improved by depositing fine precipitates by aging treatment. In addition, since the Cr content is relatively low as 0.3 mass% or more and less than 0.5 mass%, there is little Cr crystallized matter, and local strain is accumulated due to this Cr crystallized product, It can suppress that the size of a recrystallized grain becomes non-uniform | heterogenous. Therefore, even when used in a high-temperature environment, local crystal grain coarsening can be suppressed.
And in the copper alloy raw material of this invention, since the average crystal grain diameter is made into the range of 0.1 mm or more and 2.0 mm or less, accumulation | storage of distortion is comparatively small and it is hard to recrystallize. In addition, since the standard deviation of the crystal grain size is 0.6 or less, the crystal grain size is uniform, there is little accumulation of local strain, and even when used in a high temperature environment, Can prevent coarsening of crystal grains.

Here, in the copper alloy material of the present invention, it is preferable that the area ratio of Cr crystallized material in cross-sectional observation is 0.5% or less.
In this case, since the area ratio of the Cr crystallized material in the cross-sectional observation is limited to 0.5% or less, there is little accumulation of local strain, and even when used in a high temperature environment, local crystal grains Can be reliably suppressed.

In addition, in the copper alloy material of the present invention, the average crystal grain size after the heat treatment held at 1000 ° C. for 1 hour is within the range of 0.1 mm to 3.0 mm, and the standard of crystal grain size The deviation is preferably 1.5 or less.
In this case, even after a heat treatment held at 1000 ° C. for 1 hour, the crystal grains are not coarsened and the crystal grain size is relatively uniform, so it is used in a high temperature environment of 500 ° C. or higher. Even in such a case, the mechanical properties and conductivity are stable.

Moreover, in the copper alloy raw material of this invention, Al may be further included in the range of 0.1 mass% or more and 2.0 mass% or less.
In this case, in addition to Cr and Zr, Al is further included in the range of 0.1 mass% to 2.0 mass%, so that the conductivity can be adjusted to about 30 to 60% IACS. A copper alloy material having such a conductivity is particularly suitable as a molding material for casting for use in electromagnetic stirring.

In the copper alloy material of the present invention, one or more elements selected from Fe, Co, Sn, Zn, P, Si, Mg are further added in a total amount of 0.005 mass% or more and 0.1 mass%. The following may be included.
In this case, in addition to Cr and Zr, elements such as Fe, Co, Sn, Zn, P, Si, and Mg are contained within the above range. Due to the stopping effect, the coarsening of crystal grains can be more reliably suppressed.

  According to the present invention, even when used in a high temperature environment of 500 ° C. or higher, it is possible to provide a copper alloy material having stable characteristics and an excellent service life.

It is a flowchart of the manufacturing method of the copper alloy raw material which is one Embodiment of this invention. It is a structure | tissue observation photograph in an Example. (A) is Invention Example 1 and (b) is Comparative Example 4. It is a structure | tissue observation photograph after implementing the heat processing hold | maintained at 1000 degreeC for 1 hour in an Example. (A) is Invention Example 1 and (b) is Comparative Example 4. It is an observation photograph of the Cr crystallization thing in an Example. (A) is Invention Example 1 and (b) is Comparative Example 4.

Below, the copper alloy raw material which is one Embodiment of this invention is demonstrated.
The copper alloy material according to the present embodiment is used for a member used in a high temperature environment such as a casting mold or a welding member.

  The copper alloy material according to the present embodiment has a composition including Cr in the range of 0.3 mass% to less than 0.5 mass%, Zr in the range of 0.01 mass% to 0.15 mass%, and the balance of Cu and inevitable impurities. In addition, in the copper alloy raw material which is this embodiment, Al may be further included in the range of 0.1 mass% or more and 2.0 mass% or less as needed. Further, one or more elements selected from Fe, Co, Sn, Zn, P, Si, and Mg may be included within a total range of 0.005 mass% to 0.1 mass%. .

And in the copper alloy raw material which is this embodiment, while an average crystal grain diameter shall be in the range of 0.1 mm or more and 2.0 mm or less, the standard deviation of crystal grain diameter shall be 0.6 or less.
Moreover, in the copper alloy raw material which is this embodiment, the area ratio of the Cr crystallized substance in cross-sectional observation is 0.5% or less.
Further, in the copper alloy material according to the present embodiment, the average crystal grain size after the heat treatment held at 1000 ° C. for 1 hour is within the range of 0.1 mm to 3.0 mm, and the crystal grain size Standard deviation of 1.5 or less.

  The reason why the component composition, the crystal structure and the like are defined as described above in the copper alloy material according to the present embodiment will be described below.

(Cr: 0.3 mass% or more and less than 0.5 mass%)
Cr is an element having an effect of improving strength (hardness) and conductivity by finely depositing Cr-based precipitates in the crystal grains of the parent phase by aging treatment.
Here, when the Cr content is less than 0.3 mass%, the amount of precipitation becomes insufficient in the aging treatment, and the effect of improving the strength (hardness) may not be sufficiently obtained. In addition, when the Cr content is 0.5 mass% or more, a relatively large amount of Cr crystallized material exists even after the solution treatment, and local strain is accumulated due to the Cr crystallized material. The size of the recrystallized grains becomes non-uniform, and the crystal grains may become coarse when used in a high temperature environment.
From the above, in this embodiment, the Cr content is set within a range of 0.3 mass% or more and less than 0.5 mass%. In order to ensure that the above-described effects are achieved, the lower limit of the Cr content is preferably 0.35 mass% or more, and the upper limit of the Cr content is preferably 0.45 mass% or less. .

(Zr: 0.01 mass% or more and 0.15 mass% or less)
Zr is an element having an effect of improving strength (hardness) and electrical conductivity by finely depositing a Zr-based precipitate at a crystal grain boundary of the parent phase by aging treatment.
Here, when the content of Zr is less than 0.01 mass%, the precipitation amount becomes insufficient in the aging treatment, and there is a possibility that the effect of improving the strength (hardness) cannot be obtained sufficiently. Moreover, when content of Zr exceeds 0.15 mass%, there exists a possibility that electrical conductivity and thermal conductivity may fall. Moreover, even if it contains Zr exceeding 0.15 mass%, there exists a possibility that the effect of the further intensity | strength improvement may not be acquired.
From the above, in this embodiment, the content of Zr is set within a range of 0.01 mass% or more and 0.15 mass% or less. In order to ensure that the above-described effects are achieved, the lower limit of the Zr content is preferably 0.05 mass% or more, and the upper limit of the Zr content is preferably 0.13 mass% or less. .

(Al: 0.1 mass% or more and less than 2.0 mass%)
Al is an element having an effect of lowering the conductivity by dissolving in a copper alloy. Therefore, if necessary, the conductivity of the copper alloy material can be adjusted to about 30 to 60% IACS by controlling the amount of Al added.
Here, when the Al content is less than 0.1 mass%, it is difficult to keep the conductivity low. Further, when the Al content is 2.0 mass% or more, the electrical conductivity is greatly reduced, and the thermal conductivity may be insufficient.
From the above, in the present embodiment, when Al is added, the Al content is set within a range of 0.1 mass% or more and less than 2.0 mass%. In order to achieve the above-described effects, the lower limit of the Al content is preferably set to 0.3 mass% or more, and the upper limit of the Al content is preferably set to 1.5 mass% or less. . Moreover, when not intentionally adding Al, less than 0.1 mass% Al may be contained as an impurity.

(One or more elements selected from Fe, Co, Sn, Zn, P, Si, and Mg: 0.005 mass% or more and 0.1 mass% or less in total)
Elements such as Fe, Co, Sn, Zn, P, Si, and Mg are elements that form a fine compound and exhibit a pinning effect that suppresses crystal growth.
Here, when the total content of one or more elements selected from Fe, Co, Sn, Zn, P, Si, and Mg is less than 0.005 mass%, the above-described pinning effect is obtained. There is a risk that it will not be successful enough. On the other hand, when the total content of one or more elements selected from Fe, Co, Sn, Zn, P, Si, and Mg exceeds 0.1 mass%, the conductivity and thermal conductivity are May decrease.
From the above, in this embodiment, when these elements are added, the total content of one or more elements selected from Fe, Co, Sn, Zn, P, Si, and Mg is set. It is set within the range of 0.005 mass% or more and 0.1 mass% or less. In order to ensure that the above-described effects are achieved, the lower limit of the total content of one or more elements selected from Fe, Co, Sn, Zn, P, Si, and Mg is set to 0.02 mass. Preferably, the upper limit of the total content of one or more elements selected from Fe, Co, Sn, Zn, P, Si, Mg is 0.07 mass% or less. . Further, when elements such as Fe, Co, Sn, Zn, P, Si, and Mg are not intentionally added, these elements may be contained as impurities in a total amount of less than 0.005 mass%.

(Other inevitable impurities: 0.05 mass% or less)
In addition to the above-mentioned Cr, Zr, Al, Fe, Co, Sn, Zn, P, Si, Mg, other inevitable impurities include B, Ag, Ca, Te, Mn, Ni, Sr, Ba, Sc. , Y, Ti, Hf, V, Nb, Ta, Mo, W, Re, Ru, Os, Se, Rh, Ir, Pd, Pt, Au, Cd, Ga, In, Li, Ge, As, Sb, Tl , Pb, Be, N, H, Hg, Tc, Na, K, Rb, Cs, Po, Bi, lanthanoid, O, S, C and the like. Since these inevitable impurities may reduce the electrical conductivity and thermal conductivity, the total amount is preferably 0.05 mass% or less.

(Average crystal grain size: 0.1 mm to 2.0 mm / standard deviation of crystal grain size: 0.6 or less)
When the crystal grain has a fine crystal structure with an average crystal grain size of less than 0.1 mm, the driving force at the time of recrystallization increases, and high strain may be introduced locally. For this reason, when used in a high temperature environment, the crystal grains may be coarsened. On the other hand, if the average crystal grain size exceeds 2.0 mm, the processability becomes insufficient and it is difficult to use industrially. Specifically, when the grain boundary strength is lowered, the tensile strength and elongation are lowered, and the crack propagation speed is also raised, so that it is difficult to use industrially.
In addition, when the standard deviation of the crystal grain size exceeds 0.6, the crystal grain size varies widely and the strain is accumulated locally. When used in a high temperature environment, the crystal grain becomes coarse. There is a risk. Moreover, there exists a possibility that a mechanical characteristic may fall.
From the above, in this embodiment, the average crystal grain size is defined within the range of 0.1 mm to 2.0 mm, and the standard deviation of the crystal grain size is defined as 0.6 or less. The lower limit of the average crystal grain size is preferably 0.15 mm or more, and the upper limit of the average crystal grain size is preferably 1.0 mm or less. Moreover, it is preferable that the upper limit of the standard deviation of the crystal grain size is 0.5 or less.

(Area ratio of Cr crystallized material in cross-sectional observation: 0.5% or less)
When the area ratio of the Cr crystallized product exceeds 0.5%, strain is accumulated locally, so the size of the recrystallized grains is difficult to be uniform, and when used in a high temperature environment, the crystal grains May become coarse.
From the above, in this embodiment, the area ratio of the Cr crystallized product in the cross-sectional observation is regulated to 0.5% or less. In addition, it is preferable that the upper limit of the area ratio of Cr crystallized substance shall be 0.3% or less.

(Average grain size after heat treatment held at 1000 ° C. for 1 hour: 0.1 mm to 3.0 mm / standard deviation of crystal grain size: 1.5 or less)
By setting the average crystal grain size after heat treatment held at 1000 ° C. for 1 hour within the above range, coarsening of crystal grains when used in a high temperature environment is surely suppressed. In addition, when the standard deviation after heat treatment held at 1000 ° C. for 1 hour is 1.5 or less, the occurrence of variations in crystal grain size when used in a high temperature environment is surely suppressed.
From the above, in this embodiment, the average crystal grain size after the heat treatment held at 1000 ° C. for 1 hour is in the range of 0.1 mm to 3.0 mm, and the standard deviation of the crystal grain size is 1.5. It is as follows. The lower limit of the average crystal grain size is preferably 0.2 mm or more, and the upper limit of the average crystal grain size is preferably 0.5 mm or less. Moreover, it is preferable that the upper limit of the standard deviation of the crystal grain size is 1.3 or less.

  Next, the manufacturing method of the copper alloy raw material which concerns on one Embodiment of this invention is demonstrated with reference to the flowchart of FIG.

(Melting / Casting Process S01)
First, a copper raw material made of oxygen-free copper having a copper purity of 99.99 mass% or more is charged into a carbon crucible and melted using a vacuum melting furnace to obtain a molten copper. Next, the aforementioned additive elements are added to the obtained molten metal so as to have a predetermined concentration, and the components are prepared to obtain a molten copper alloy.
Here, as the raw material for the additive elements Cr and Zr, a material having a high purity is used. For example, a Cr material having a purity of 99.99 mass% or more is used, and a Zr material is having a purity of 99.95 mass% or more. Use one. Al, Fe, Co, Sn, Zn, P, Si, and Mg are added as necessary. A mother alloy with Cu may be used as a raw material for Cr, Zr, Al, Fe, Co, Sn, Zn, P, Si, and Mg.
And the ingot is obtained by pouring the prepared copper alloy melt into the mold.

(Homogenization step S02)
Next, heat treatment is performed to homogenize the obtained ingot.
Specifically, the ingot is homogenized in an air atmosphere at 950 ° C. or higher and 1050 ° C. or lower for 1 hour or longer.

(Hot processing step S03)
Next, hot rolling with a processing rate of 50% to 99% is performed on the ingot in a temperature range of 900 ° C. to 1000 ° C. to obtain a rolled material. The hot working method may be hot forging. Immediately after this hot working, it is cooled by water cooling.

(Solution treatment step S04)
Next, the rolled material obtained in the hot working step S03 is subjected to a heat treatment under conditions of 920 ° C. or higher and 1050 ° C. or lower and 0.5 hours or longer and 5 hours or shorter. The heat treatment is performed in, for example, air or an inert gas atmosphere, and cooling after heating is performed by water cooling.

(Aging treatment step S05)
Next, after the solution treatment step S04, a first temporary effect treatment is performed, and precipitates such as a Cr-based precipitate and a Zr-based precipitate are finely precipitated to obtain a first temporary effect treatment material.
Here, the aging treatment is performed under conditions of, for example, 400 ° C. or more and 530 ° C. or less and 0.5 hour or more and 5 hours or less.
The heat treatment method during the aging treatment is not particularly limited, but it is preferably performed in an inert gas atmosphere. Further, the cooling method after the heat treatment is not particularly limited, but it is preferably performed by water cooling.
The copper alloy material which is this embodiment is manufactured by such a process.

  According to the copper alloy material according to the present embodiment configured as described above, Cr includes 0.3 mass% or more and less than 0.5 mass%, Zr includes 0.01 mass% or more and 0.15 mass% or less, and the balance is Since it is set as the composition which consists of Cu and an unavoidable impurity, by performing a solution treatment and an aging treatment, a fine precipitate can be deposited and an intensity | strength and electrical conductivity can be improved.

  Further, since the Cr content is relatively low at 0.3 mass% or more and less than 0.5 mass%, there is almost no Cr crystallized product after the solution treatment. Specifically, the area ratio of Cr crystallized material in cross-sectional observation is 0.5% or less. Therefore, it is possible to prevent local strain from being accumulated due to the Cr crystallized product and to make the recrystallized grains non-uniform in size. Even when used in a high temperature environment, the local crystal grains are coarse. Can be reliably suppressed.

In this embodiment, the average crystal grain size is in the range of 0.1 mm to 2.0 mm, and the standard deviation of the crystal grain size is 0.6 or less. Even when used in a high temperature environment, local grain coarsening can be suppressed.
Furthermore, the average crystal grain size after carrying out the heat treatment held at 1000 ° C. for 1 hour is in the range of 0.1 mm to 3.0 mm, and the standard deviation of the crystal grain size is 1.5 or less. Even after the heat treatment held at 1000 ° C. for 1 hour, even if the crystal grains are not locally coarsened and used in a high temperature environment of 500 ° C. or higher, the mechanical properties and conductivity The rate is stable.

Moreover, in this embodiment, when Al is further contained in the range of 0.1 mass% or more and 2.0 mass% or less, the conductivity can be adjusted to about 30 to 60% IACS. Thereby, it is possible to obtain a copper alloy material particularly suitable as a molding material for casting for use in electromagnetic stirring.
In the present embodiment, when one or more elements selected from Fe, Co, Sn, Zn, P, Si, and Mg are further included in a total of 0.005 mass% to 0.1 mass%. The coarsening of the crystal grains can be further reliably suppressed by the pinning effect by the compound containing these elements.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention.

Below, the result of the confirmation experiment performed in order to confirm the effect of this invention is demonstrated.
A copper raw material made of oxygen-free copper having a purity of 99.99 mass% or more was prepared, charged into a carbon crucible, and melted in a vacuum melting furnace (vacuum degree: 10 ⁻² Pa or less) to obtain a molten copper. Various additive elements were added to the obtained molten copper to prepare the component compositions shown in Table 1, and after maintaining for 5 minutes, the molten copper alloy was poured into a cast iron mold to obtain an ingot. The size of the ingot was about 80 mm in width, about 50 mm in thickness, and about 130 mm in length.
In addition, the raw material of Cr, which is an additive element, was used with a purity of 99.99 mass% or more, and the raw material of Zr was a purity of 99.95 mass% or more.

Next, after performing a homogenization process at 1000 ° C. for 1 hour in an air atmosphere, hot rolling was performed. The rolling reduction during hot rolling was 80%, and a hot rolled material having a width of about 100 mm, a thickness of about 10 mm, and a length of about 520 mm was obtained.
Using this hot-rolled material, solution treatment was performed at 1000 ° C. for 1.5 hours, followed by cooling at a cooling rate shown in Table 2.
Next, an aging treatment was performed at 500 (± 15) ° C. for 3 hours. Thereby, a copper alloy material was obtained.

About the obtained copper alloy raw material, the structure | tissue observation of the copper alloy raw material after an aging treatment was performed, and the standard deviation of the average crystal grain diameter and crystal grain diameter was measured.
In addition, the average crystal grain size and the standard deviation of the crystal grain size after the heat treatment of holding the copper alloy material at 1000 ° C. for 1 hour were measured.
Furthermore, the cross-sectional observation was performed about the material after solution treatment, and the area ratio of Cr crystallization thing was measured.

(Composition analysis)
The component composition of the obtained copper alloy material was measured by ICP-MS analysis. The measurement results are shown in Table 1.

(Average crystal grain size and standard deviation of crystal grain size)
A sample of 10 mm × 15 mm was cut out from the center of the plate width with the plate thickness of the obtained copper alloy material, and the surface in the rolling direction (RD direction) was polished and then microetched.
This sample was observed, and the average crystal grain size was measured by a cutting method defined in JIS H 0501.

(Area ratio of Cr crystallized product)
A sample of 10 mm × 15 mm was cut out from the center of the plate width with the thickness of the copper alloy material, and the surface in the rolling direction (RD direction) was polished and then microetched.
This sample was observed by SEM, and in the SEM-EPMA image of 1500 times (approximately 70 μm × 70 μm visual field), it was judged that the region having a higher Cr concentration than the parent phase was “Cr crystallized product”. The area ratio was determined by the following formula.
Area ratio = (area occupied by Cr crystallized product) / (70 μm × 70 μm)
FIG. 4 shows SEM-EPMA images of Example 1 and Comparative Example 4.

(Tensile strength)
A JIS Z 2241 No. 2 test piece was taken with the rolling direction as the tensile direction, and was subjected to the test using a 100 kN tensile tester.

In Comparative Example 1 in which the Cr content is less than the range of the present invention and the standard deviation of the crystal grain size is greater than the range of the present invention, the tensile strength after aging heat treatment and after heat treatment at 1000 ° C. for 1 hour is insufficient. there were.
In Comparative Example 2-4 in which the Cr content is larger than the range of the present invention, the average crystal grain size is smaller than that of the present invention, and the standard deviation of the crystal grain size is larger than the range of the present invention, heat treatment is performed at 1000 ° C. for 1 hour. Later, the tensile strength was greatly reduced.

On the other hand, in Inventive Example 1-6, the tensile strength after the aging heat treatment was high, and the tensile strength was not significantly reduced after the heat treatment at 1000 ° C. for 1 hour.
From the above, according to the present invention example, it is possible to provide a copper alloy material having stable characteristics and excellent service life even when used in a high temperature environment of 500 ° C. or higher. Was confirmed.

Claims (5)

Cr has a composition composed of 0.3 mass% or more and less than 0.5 mass%, Zr 0.01 mass% or more and 0.15 mass% or less, and the balance consisting of Cu and inevitable impurities,
A copper alloy material having an average crystal grain size in a range of 0.1 mm to 2.0 mm and a standard deviation of crystal grain size of 0.6 or less.   2. The copper alloy material according to claim 1, wherein the area ratio of the Cr crystallized product in cross-sectional observation is 0.5% or less.   The average crystal grain size after carrying out the heat treatment held at 1000 ° C. for 1 hour is in the range of 0.1 mm to 3.0 mm, and the standard deviation of the crystal grain size is 1.5 or less The copper alloy material according to claim 1 or claim 2.   Furthermore, Al is contained within the range of 0.1 mass% or more and 2.0 mass% or less, The copper alloy raw material as described in any one of Claims 1-3 characterized by the above-mentioned.   Furthermore, it contains one or more elements selected from Fe, Co, Sn, Zn, P, Si, and Mg within a total range of 0.005 mass% to 0.1 mass%. The copper alloy material according to any one of claims 1 to 4.