TW201639974A - Copper alloy having excellent heat resistance - Google Patents

Abstract

The subject of the present invention is to provide a high strength, high electrical conductivity, and excellent heat resistance Cu-Fe-P based copper alloy. The solution of the present invention is a copper alloy having excellent heat resistance, which contains, in mass percentage, Fe: 1.8 ~ 2.7%, P: 0.01 ~ 0.20%, Zn: 0.01 ~ 0.30%, Sn: 0.01 ~ 0.2%, the balance of copper and unavoidable impurities. The compounds with equivalent diameter exceeding 1[mu]m per mm2 of observed field area is more than 0 and less than 5.0 x 10^3. The compounds with equivalent diameter of 100 ~ 200 nm per mm2 of observed field area is 1.0 x 10^5 ~ 1.0 × 10^7.

Description

Copper alloy with excellent heat resistance

The present invention relates to a copper alloy, and more particularly to a copper alloy having high strength, high electrical conductivity, and excellent heat resistance.

A copper alloy can be used in the raw material of the semiconductor lead frame. As the copper alloy, a Cu-Fe-P-based copper alloy containing Fe and P has been conventionally used. The Cu-Fe-P-based copper alloy system is exemplified by a CDA194 alloy, specifically, Fe: 2.1 to 2.6 mass%, P: 0.015 to 0.15 mass%, Zn: 0.05 to 0.20 mass%, and the remainder is Cu and not A copper alloy consisting of impurities. The Cu-Fe-P-based copper alloy is high in strength by precipitation of an intermetallic compound such as Fe or Fe-P in the matrix phase, and has excellent conductivity and excellent thermal conductivity. Therefore, it is widely used as an international standard alloy.

In recent years, with the increase in capacity, size, thickness, and functionality of semiconductor devices used in electronic devices, the development of a lead frame for semiconductor devices has been reduced, and further strength and conductivity have been required. Sexual, thermal conductivity. Along with this, the copper alloy sheets used for the lead frames of such semiconductor devices are also required to be further advanced. High strength in one step, high conductivity, and good thermal conductivity.

For example, Patent Document 1 discloses a technique for improving the strength, electrical conductivity, bending workability, and stress relaxation resistance of a copper alloy sheet for an electric electronic component. According to this technique, the strength and conductivity of the copper alloy sheet are improved by providing a relatively large amount of Fe of 2.5 to 3.5% by mass and depositing a two-phase structure of the second phase particles in the Cu mother phase.

However, if the content of Fe is too large, the conductivity may be deteriorated instead. In order to improve conductivity, for example, the precipitation amount of precipitated particles such as Fe or Fe-P may be increased. However, it is known that when the precipitation amount of the precipitated particles is increased, the growth and coarsening of the precipitated particles are caused, and the strength or heat resistance is lowered.

When the Cu-Fe-P-based copper alloy sheet is processed into a lead frame or the like, it is generally formed into a multi-pin shape by press working (sometimes referred to as press-punching processing). Recently, in order to reduce the size and thickness of a semiconductor device used in an electronic device as described above, it has been developed to reduce the thickness of a copper alloy sheet used as a material or to increase the number of pins of a lead frame or the like. Along with this, there is a tendency that the processed product after the press working is likely to have residual deformation stress, and the pin tends to be irregular. Therefore, in the multi-pin shape copper alloy sheet obtained by press working, heat treatment such as stress relief annealing is usually applied to remove the deformation. However, if such heat treatment is performed, the material is easily softened and the strength before the heat treatment cannot be maintained. Further, in order to improve productivity, the above heat treatment is required to be carried out at a high temperature and for a short period of time, and it is strongly required to maintain high-strength heat resistance after heat treatment at a high temperature.

Further, in Patent Documents 2 to 4, it is disclosed that a copper alloy is used. Technology for improving strength, electrical conductivity, and heat resistance.

Patent Document 2 discloses an area ratio S _{1 in which} the total area of precipitates having an area of 20 nm ² or more and less than 200 nm ² in the Fe precipitate dispersed in the Cu mother phase accounts for the ratio of the entire Cu mother phase. 0.4% or more, and the area ratio S ₂ of the total area of the precipitates having an area of 200 nm ² or more and the ratio of the total amount of the Cu mother phase is 0.4 ≦S ₁ /S ₂ ≦1.4, thereby improving the strength. Technology of electrical conductivity and heat resistance.

Patent Document 3 discloses a fine Fe-based compound which inhibits the coarse Fe-based compound of 0.1 μm or more separated by a filter having a pore size of 0.1 μm by an extraction residue method, thereby contributing to an improvement in strength. The ratio is increased to improve the strength, electrical conductivity, and heat resistance.

In Patent Document 4, it is disclosed that the density of Fe-P particles having a particle diameter of 1 μm or more is 30/mm ² or less, and the density of γ Fe particles and α Fe particles is increased to improve strength and conductivity. And heat resistance technology.

Further, although it is not a technique for improving the strength, electrical conductivity, and heat resistance of the copper alloy, Patent Document 5 discloses that in the cross section perpendicular to the casting direction after continuous casting, the crystal grains are present and present. The average value of the major axis of the primary-crystal iron particles at the grain boundary is set to 5 μm or less, thereby reducing the number of surface defects or internal cracks in the copper alloy sheet to be a product.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2012-207261

[Patent Document 2] Japanese Patent No. 5555154

[Patent Document 3] Japanese Patent No. 4950584

[Patent Document 4] Japanese Patent Laid-Open Publication No. 2014-55341

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2013-71155

In the technique of Patent Document 1, although the strength and conductivity of the copper alloy sheet are improved, heat resistance is not taken into consideration.

Furthermore, in the technique of the above-mentioned Patent Document 2, very fine precipitates having a diameter of several nm to several tens of nm are deposited, and in the techniques of Patent Documents 3 to 5, the Fe-based compound of 0.1 μm or more is controlled to control the Fe-based compound. There is a ratio or size. However, as a result of investigations, the inventors of the present invention found that the relationship between the number density, the strength, the electrical conductivity, and the heat resistance of a compound having a substantially circular diameter of 100 to 200 nm has not been examined.

The present invention has been made in view of the above-described circumstances, and an object of the invention is to provide a Cu-Fe-P-based copper alloy which is high in strength, high in electrical conductivity, and further excellent in heat resistance.

The copper alloy having excellent heat resistance according to the present invention, which is capable of solving the above problems, contains Fe: 1.8 to 2.7%, P: 0.01 to 0.20%, Zn: 0.01 to 0.30%, and Sn: 0.01 to 0.2% by mass%. The remaining part is a copper alloy composed of copper and unavoidable impurities. And having the following gist: circle-equivalent diameter of 1μm of Compound over based on the observation visual field area per 1mm ² of less than 0, 5.0 × 10 ³ or less, the circle equivalent diameter of 100 ~ 200nm of the compound based on an observation visual field area per 1mm ² The medium is 1.0 × 10 ⁵ ~ 1.0 × 10 ⁷ . In addition, hereinafter, % means a mass % with respect to a chemical component.

The copper alloy may further be one or more selected from the group consisting of Si, Ni, and Co in a mass%: a total of 0.01 to 0.1%.

According to the present invention, a Cu-Fe-P-based copper alloy having high strength, high electrical conductivity, and excellent heat resistance can be provided by appropriately controlling the number density of the component composition and the specific size of the compound.

The inventors of the present invention have tried to provide a copper alloy of Cu-Fe-P type which is excellent in heat resistance and high in heat resistance. As a result, it has been found that, if the composition of the copper alloy is appropriately controlled, and among the compounds contained in the copper alloy, (A) a compound having a substantially circular diameter of more than 1 μm is set to 0 in the observation field area per 1 mm ² . More than or equal to 5.0 × 10 ³ or less, (B) a compound having a substantially circular diameter of 100 to 200 nm is set to 1.0 × 10 ⁵ to 1.0 × 10 ⁷ per 1 mm ² of the observation visual field area, thereby achieving strength and conductivity. The present invention has been completed by a copper alloy excellent in both properties and heat resistance.

Further, it is known that the copper alloy of the present invention is obtained by dissolving and casting a copper alloy having a compositional adjustment, and after the obtained ingot is subjected to a soaking treatment, hot rolling can be performed, in particular, for the number density of the compound. The control is in the above range, and the soaking conditions and the hot rolling conditions may be appropriately adjusted.

Hereinafter, the present invention will be described in detail.

(A) Number density of compounds having a diameter of more than 1 μm

The copper alloy of the present invention has a compound having a diameter of more than 1 μm and is 0 or more and 5.0 × 10 ³ or less per 1 mm ² of the observation field of view. When the number density of the compound having a diameter of more than 1 μm exceeds 5.0 × 10 ³ /mm ² , the compound having a substantially circular diameter of 100 to 200 nm and the equivalent circle diameter generated in one annealing or second annealing are nm. The amount of tens of nm of compound produced will be reduced. As a result, strength, electrical conductivity, and heat resistance are deteriorated. Moreover, it is a cause of cracking at the time of press-punching processing. Therefore, in the present invention, the number density of the compound having a substantially circular diameter of more than 1 μm is set to 5.0 × 10 ³ /mm ² or less. The number density of the compound having a substantially circular diameter of more than 1 μm is preferably 4.5 × 10 ³ /mm ² or less, more preferably 4.0 × 10 ³ /mm ² or less. The number density of the compound having a substantially circular diameter of more than 1 μm is preferably as small as possible, and most preferably 0 / mm ² .

(B) Number density of compounds with a relatively round diameter of 100 to 200 nm

The copper alloy of the present invention has a compound having a diameter of 100 to 200 nm and is 1.0 × 10 ⁵ or more and 1.0 × 10 ⁷ or less per 1 mm ² of the observation field area. In other words, the compound having a substantially circular diameter of 100 to 200 nm is made 0.10 × 10 ⁶ or more and 10 × 10 ⁶ or less. Although the compound having a substantially circular diameter of 100 to 200 nm has not been particularly noticed in the past, the inventors of the present invention have first discovered that it contributes to the improvement of the electrical conductivity and heat resistance of the copper alloy. In order to exert such an effect, the number density of compounds having a substantially circular diameter of 100 to 200 nm is set to 1.0 × 10 ⁵ or more. The number density of the compound having a substantially circular diameter of 100 to 200 nm is preferably 5.0 × 10 ⁵ /mm ² or more. However, if the number density of a compound having a diameter of 100 to 200 nm is too large, the amount of the compound of several nm to several tens of nm generated in one annealing and second annealing is reduced, the strength of the copper alloy is lowered, and the heat resistance is reversed. Will deteriorate. Therefore, the number density of the compound having a relatively large circular diameter of 100 to 200 nm must be 1.0 × 10 ⁷ or less. The number density of the compound having a substantially circular diameter of 100 to 200 nm is preferably 8.0 × 10 ⁶ /mm ² or less, more preferably 5.0 × 10 ⁶ /mm ² or less.

A compound having a substantially circular diameter of more than 1 μm and a number density of a compound of 100 to 200 nm may be measured by the following procedure. In other words, the number density of the compound having a diameter of more than 1 μm is a scanning type in the cross section in the width direction of the test piece, for example, in the thickness direction of the central portion of the thickness of 90 μm × the cross-sectional direction of 125 μm. An electron microscope was observed at a magnification of 1000 times, and the equivalent circle diameter of each compound was calculated using an image analysis software to obtain a fairly straight straight line. The number of compounds having a diameter of more than 1 μm may be calculated by dividing the area of the observation field of view.

The number density of a compound having a substantially circular diameter of 100 to 200 nm is obtained by a scanning electron microscope and a magnification in a cross-sectional view, for example, in a thickness direction of a central portion of the plate thickness of 9.0 μm × a cross-sectional direction of 12.5 μm. The observation was performed at 10,000 times, and the equivalent circle diameter of each compound was calculated using the image analysis software in the same manner as described above, and the number of compounds having a diameter of 100 to 200 nm was determined and divided by the observation field of view. Further, the type of the compound to be analyzed is not particularly limited.

As the image analysis software, for example, Image-Pro Plus manufactured by Macromedia Co., Ltd. can be used.

Further, in the technique disclosed in Patent Document 3, as described above, the Fe-based compound having a thickness of 0.1 μm or more separated by a filter having a pore size of 0.1 μm is suppressed by the extraction residue method. However, in this technique, it is not possible to individually calculate a compound having a substantially circular diameter of more than 1 μm and a number density of a compound of 100 to 200 nm as in the present invention. In addition, in the above-mentioned Patent Document 5, the average value of the long diameter of the primary iron particles is suppressed to 5 μm or less. In the above Patent Document 4, the density of Fe-P particles having a particle diameter of 1 μm or more is described. 30 / mm ² or less. However, in Patent Documents 4 and 5, the number density of compounds having a substantially circular diameter of 100 to 200 nm is not considered at all.

The copper alloy of the present invention is a number density of a compound having a diameter of more than 1 μm, and the number density of the compound of 100 to 200 nm is full. The above range is important. Further, the component composition must satisfy Fe: 1.8 to 2.7%, P: 0.01 to 0.20%, Zn: 0.01 to 0.30%, and Sn: 0.01 to 0.2% by mass%.

Fe is an element necessary for improving strength and heat resistance by solid solution in a mother phase of a copper alloy or formation of a Fe-based compound. When the amount of Fe is less than 1.8%, the amount of solid solution or precipitation of Fe may be insufficient, and strength and heat resistance may not be obtained. Therefore, in the present invention, the amount of Fe is set to 1.8% or more. The amount of Fe is preferably 2.1% or more. However, if the amount of Fe is excessive, a coarse Fe compound is formed, which causes cracking during piercing. Therefore, in the present invention, the amount of Fe is set to 2.7% or less. The amount of Fe is preferably 2.6% or less, more preferably 2.4% or less.

P is an element which functions to deoxidize oxygen mixed in the molten liquid, and is an element which forms a compound with Fe to enhance the strength and heat resistance of the copper alloy. In order to exert such an effect, the P amount must be set to 0.01% or more. The amount of P is preferably 0.02% or more. However, if the amount of P becomes excessive, the electrical conductivity will decrease. Also, hot workability is lowered. Therefore, in the present invention, the P amount is set to 0.20% or less. The amount of P is preferably 0.15% or less.

Zn is an element necessary for improving the heat-resistant peeling property of the solder of the copper alloy or the heat-resistant peeling property of the Sn-plating of the copper alloy. Such heat-resistant peeling property is, for example, a property required when a copper alloy is used for a lead frame or the like. In order to exert such an effect, the amount of Zn must be 0.01% or more. The amount of Zn is preferably 0.05% or more. However, if the amount of Zn is excessive, the electrical conductivity will decrease. Also, for the soldering of copper alloys Runability will decrease. Therefore, in the present invention, the amount of Zn is set to 0.30% or less. The amount of Zn is preferably 0.20% or less.

Sn is an element necessary for improving the strength and heat resistance of the copper alloy. In order to exert such an effect, the amount of Sn must be set to 0.01% or more. The amount of Sn is preferably 0.02% or more. However, if the amount of Sn becomes excessive, the electrical conductivity is lowered. Also, the hot workability is also lowered. Therefore, in the present invention, the amount of Sn is set to 0.2% or less. The amount of Sn is preferably 0.10% or less, more preferably 0.05% or less.

The remainder of the copper alloy of the present invention is copper and unavoidable impurities.

The copper alloy of the present invention may further contain one or more selected from the group consisting of Si, Ni, and Co in a total amount of 0.01% to 0.1% by mass.

Si, Ni, and Co are elements which form a compound with Fe or P to enhance the strength and heat resistance of the copper alloy. In order to effectively exhibit such an effect, it is preferable to set one or more selected from Si, Ni, and Co to 0.01% or more in total, and more preferably 0.03% or more. However, if an element such as Si is excessively contained, the compound is coarsened, which causes cracking during punching and punching. Therefore, in the present invention, one or more selected from the group consisting of Si, Ni, and Co are preferably 0.1% or less in total, and more preferably 0.08% or less.

The copper alloy of the present invention has a tensile strength of 530 MPa or more, a conductivity of 60% IACS or more, and a Vickers hardness of 155 Hv or more. Moreover, the Vickers hardness after annealing at 475 ° C for 1 minute becomes 140 Hv. The above is a copper alloy having excellent heat resistance.

Next, preferred manufacturing conditions of the copper alloy of the present invention will be described.

First, the copper alloy having the compositional composition adjusted is dissolved and cast, and the obtained ingot is subjected to a soaking treatment, followed by hot rolling. In order to control the number density of the compound to the above range, the soaking conditions and the hot rolling conditions may be appropriately adjusted. The dissolution and casting of the copper alloy may be carried out according to the usual method.

In the soaking treatment, the ingot may be heated to 800 ° C or higher and less than 950 ° C, and may be kept for a certain period of time as needed. The holding time is, for example, 10 to 120 minutes. When the temperature of the soaking treatment is lower than 800 ° C, a compound having a relatively large diameter of 100 to 200 nm is formed in a large amount, and the number density tends to be high. Therefore, in the present invention, the temperature of the soaking treatment is preferably set to 800 ° C or higher. The temperature of the soaking treatment is more preferably 830 ° C or more, and still more preferably 850 ° C or more. However, when the temperature of the soaking treatment is 950 ° C or more, a compound having a substantially circular diameter of more than 1 μm is formed in a large amount, and the number density tends to be high. Therefore, in the present invention, the temperature of the soaking treatment is preferably set to less than 950 °C. The temperature of the soaking treatment is more preferably 940 ° C or less, still more preferably 920 ° C or less. For example, it is presumed that in Patent Document 4, since the ingot is heated to 1020 to 1080 ° C and held for 2 hours or more, a compound having a substantially circular diameter of more than 1 μm is excessively formed. Therefore, it is presumed that the strength of the above-described Patent Document 4 is too low.

After the soaking treatment, hot rolling is performed. The reduction ratio of the hot rolling is not particularly limited as long as it is the thickness of the board to be used and the subsequent steps. The relationship between the cold rolling ratio in cold rolling can be determined. In addition, the hot rolling system can be carried out once or in multiple times.

In the production of the copper alloy of the present invention, it is particularly preferable to set the end temperature of hot rolling to 700 ° C or higher and less than 850 ° C. When the end temperature of the hot rolling is less than 700 ° C, a compound having a substantially circular diameter of 100 to 200 nm is formed in a large amount, and the number density is likely to be high. Therefore, in the present invention, the end temperature of the hot rolling is preferably set to 700 ° C or higher. The end temperature of the hot calendering is more preferably 730 ° C or more, and still more preferably 750 ° C or more. However, when the end temperature of the hot rolling is 850 ° C or more, a compound having a diameter of more than 1 μm is formed in a large amount, and the number density tends to be high. Therefore, in the present invention, the end temperature of the hot rolling is preferably set to less than 850 °C. The end temperature of the hot rolling is more preferably 840 ° C or less, and still more preferably 830 ° C or less.

After hot rolling, it is only necessary to rapidly cool to room temperature. When the cooling rate after the hot rolling is small, a large amount of a compound having a relatively large diameter of more than 1 μm during the cooling process is precipitated in a large amount, and it becomes difficult to form a specific amount of a fine compound having a diameter of 100 to 200 nm. In the present invention, rapid cooling means cooling at an average cooling rate exceeding air cooling, and is preferably 20 ° C /sec or more. Although the upper limit of the average cooling rate is not particularly limited, it is preferably about 500 ° C / sec or less in consideration of actual production or the like.

The rapid cooling means is not particularly limited, and for example, a known cooling means such as water cooling can be used.

After the rapid cooling, the heat treatment by the first annealing is applied to the sheet material after the first cold rolling (hereinafter referred to as primary cold rolling), and then the second cold rolling (hereinafter referred to as 2) Secondary cold The calendering is formed into a specific shape, and thereafter, the deformation in the copper alloy structure can be removed by applying heat treatment by annealing twice.

Although the calendering rate of the cold rolling is arbitrary, it may be adjusted by blending the thickness of the final sheet and the calendering rate of the second cold rolling to be described later.

After the primary cold rolling, for example, by applying annealing at 450 to 650 ° C for 30 minutes to 24 hours, the number density of the compound having a substantially circular diameter of 100 to 200 nm can be controlled to an appropriate range. When the annealing temperature is less than 450 ° C or the annealing time is less than 30 minutes, the number of compounds having a relatively round diameter of 100 to 200 nm is easily lowered due to insufficient heat treatment, and the conductivity is easily lowered. . On the other hand, when the primary annealing temperature exceeds 650 ° C, the number density of the compound having a substantially circular diameter of 100 to 200 nm tends to be high, and the strength is likely to be lowered. Moreover, if the annealing time exceeds 24 hours, energy loss is caused, and it is not economically efficient.

Next, after one annealing, cold rolling was applied twice. The strength of the copper alloy sheet can be improved by introducing cold deformation into the metal structure by two cold rolling. The rolling reduction ratio of the second cold rolling may be, for example, 25 to 70%. The rolling reduction rate in the second cold rolling is less than 25%, and the deformation amount accumulated in the metal structure by rolling is lowered, and it is difficult to obtain sufficient strength. On the other hand, if the rolling reduction ratio of the secondary cold rolling exceeds 70%, the shape variable accumulated in the metal structure is saturated, and it is difficult to obtain an improvement in strength.

Then, after 2 cold rolling, it is better to enter 250~450 °C. The annealing is performed twice in 20 to 1000 seconds. The secondary annealing is an annealing for obtaining deformation which is introduced in the second cold rolling, and may be removed by a movable deformation in a low temperature region of 250 to 450 °C. When the annealing temperature is less than 250 ° C or the annealing time is less than 20 seconds, the removal of the movable deformation becomes insufficient, and the electrical conductivity is liable to lower. On the other hand, if the secondary annealing temperature exceeds 450 ° C or the secondary annealing time exceeds 1000 seconds, the deformation is excessively removed, and the strength is liable to lower.

[Examples]

In the following, the present invention will be more specifically described by the following examples, but the present invention is not limited by the following examples, and of course, it may be implemented by adding or modifying the modifications within the scope of the above-mentioned and the following description. All of them are included in the technical scope of the present invention.

A copper alloy having the composition shown in Table 1 below and having the remainder consisting of copper and unavoidable impurities is ingots in a coreless furnace, and then agglomerated by a semi-continuous casting method to produce An ingot having a thickness of 70 mm × a width of 200 mm and a length of 500 mm. Further, the results of calculating the total amount of Si, Ni, and Co are also shown in Table 1 below.

After the surface of the obtained ingot was subjected to surface cutting, it was subjected to a soaking treatment at a temperature of 750 to 1050 ° C for 1 hour, and then hot rolling was carried out to obtain a hot rolled sheet having a thickness of 15 mm. The temperature of the soaking treatment is shown in Table 2 below. The hot rolling start temperature is adjusted such that the hot rolling end temperature is 600 to 800 ° C, and immediately after the hot rolling is finished, the cooling is rapidly performed by water cooling. Table 2 below shows the hot rolling end temperature degree.

Next, after the scale was removed, cold rolling, primary annealing, secondary cold rolling, and secondary annealing were performed once to obtain a cold rolled sheet having a thickness of 0.25 mm. The primary annealing was carried out by heating to 550 ° C and maintaining the temperature at this temperature for 4 hours. The secondary annealing was carried out by heating to 350 ° C and maintaining the temperature for 60 seconds.

The number density, tensile strength, electrical conductivity, hardness, and heat resistance of the compound were measured for the obtained cold rolled sheet.

The number density of the compounds is determined for a compound having a substantially circular diameter of more than 1 μm and a compound having a substantially circular diameter of 100 to 200 nm.

The number density of a compound having a substantially circular diameter of more than 1 μm is in the transverse cross section of the cold rolled sheet in the width direction, and is observed by a scanning electron microscope in a region of a thickness of 90 μm in the central portion of the thickness and a cross section of 125 μm in the cross section. The magnification was observed at 1000 times, and the image-analytical software (Image-Pro Plus manufactured by Macromeda) was used to measure the considerable circle diameter of the compound in the observation field. The measurement results are shown in Table 2 below.

The number density of a compound having a substantially circular diameter of 100 to 200 nm is in a transverse cross section of the cold rolled sheet in the width direction, and a scanning electron microscope is applied to a region having a thickness of 9.0 μm in the central portion of the thickness and 12.5 μm in the cross section. The observation magnification was observed at 10,000 times, and the above-mentioned image analysis software was used to measure the considerable circle diameter of the compound in the observation field. The measurement results are shown in Table 2 below.

The tensile strength was measured using a JIS No. 13 B test piece cut out from the above-mentioned cold rolled sheet, and a universal tester manufactured by Model 5882 Instron. The tensile strength was measured at room temperature, and the test speed was set to 10.0 mm/min, and the distance GL between the lines was set to 50 mm. The measurement results are shown in Table 2 below. In the present embodiment, the tensile strength of 530 MPa or more was regarded as acceptable.

In the electrical conductivity, a test piece having a length of 10 mm and a length of 300 mm was polished by the above-described cold rolled sheet, and the electric resistance was measured by a double bridge type resistance measuring device, and was calculated by an average sectional area method. The calculation results are shown in Table 2 below. In the present invention, 60% IACS or more was regarded as acceptable, and it was evaluated that the conductivity was good.

For the hardness, a Micro Vickers hardness tester (trade name "micro hardness tester") manufactured by Matsuzaka Seiki Co., Ltd. was used, and a load of 0.5 kg was applied to measure at three places, and an average value was obtained. The calculation results are shown in Table 2 below. In the present embodiment, a hardness of 155 Hv was regarded as acceptable.

When the tensile strength was 530 MPa or more and the hardness was 155 Hv or more, it was evaluated as high strength, and it was set as the invention example. On the other hand, a case where at least one of the tensile strength and the hardness did not reach the pass criteria was used as a comparative example.

The heat resistance was obtained by simulated annealing of the cold rolled sheet and heating at 475 ° C for 1 minute, and then using a Micro Vickers hardness meter (trade name "micro hardness meter") manufactured by Matsuzaka Seiki Co., Ltd., and applying a load of 0.5 kg to measure the hardness. The measurement results are shown in Table 2 below. Yu Benfa In the Ming Dynasty, 140 Hv or more was regarded as qualified, and it was evaluated as having excellent heat resistance.

The following Table 2 can be examined as follows.

No. 1 to 8 are examples in which the requirements specified in the present invention are satisfied, and since the composition of the component is appropriately controlled, and the number of compounds having a substantially circular diameter of more than 1 μm and the number of compounds having a substantially circular diameter of 100 to 200 nm satisfy a specific condition, Therefore, a copper alloy having high strength and excellent electrical conductivity and excellent heat resistance can be obtained.

No. 11 to 18 are examples in which any of the requirements specified in the present invention are not satisfied.

Specifically, No. 11 is an example in which the amount of Fe is excessive and the number density of compounds having a diameter of more than 1 μm is too high. As a result, the electrical conductivity is lowered.

No. 12 is an example in which the amount of Fe is too small, the tensile strength and hardness are low, and the heat resistance cannot be improved.

No. 13 is an example in which the amount of P is excessive, and the number density of a compound having a diameter of more than 1 μm is too high. As a result, tensile strength, hardness, and electrical conductivity are low, and heat resistance cannot be improved.

No. 14 is an example in which the amount of Sn is excessive, and the electrical conductivity is lowered.

No. 15 was subjected to soaking treatment at a temperature higher than the temperature range recommended by the present invention at 980 °C. As a result, the number density of the compound having a substantially circular diameter of more than 1 μm is too high, and heat resistance cannot be improved.

No. 16 was subjected to a soaking treatment at a temperature of 1050 ° C higher than the temperature range recommended by the present invention, and the hot rolling was terminated at a lower temperature of 600 ° C than the temperature range recommended by the present invention. The result is quite round diameter 100~ The number density of 200 nm is too high, and the tensile strength and hardness are lowered.

No. 17 ends the hot rolling at 670 ° C lower than the temperature range recommended by the present invention. As a result, the number density of a relatively large circular diameter of 100 to 200 nm is too high, and the tensile strength and hardness are lowered.

No. 18 was subjected to soaking treatment at a temperature lower than the temperature range recommended by the present invention at 750 ° C, and the hot rolling was terminated at a lower temperature of 650 ° C than the temperature range recommended by the present invention. As a result, the number density of a relatively large circular diameter of 100 to 200 nm is too high, the tensile strength and hardness are lowered, and heat resistance cannot be improved.

Claims (2)

A copper alloy having excellent heat resistance, which contains Fe: 1.8 to 2.7%, P: 0.01 to 0.20%, Zn: 0.01 to 0.30%, Sn: 0.01 to 0.2% by mass%, and the balance is copper and A copper alloy composed of an unavoidable impurity is characterized in that a compound having a diameter of more than 1 μm is a compound having 0 or more and 5.0 × 10 ³ or less per 1 mm ² of the observed field of view, and a compound having a diameter of 100 to 200 nm. The area of the observation field of view is 1.0 × 10 ⁵ to 1.0 × 10 ⁷ per 1 mm ² . The copper alloy of claim 1, which is further selected from the group consisting of Si, Ni, and Co in mass%, and contains 0.01 to 0.1% in total.