JP4779100B2 - Manufacturing method of copper alloy material - Google Patents

Description

  The present invention relates to a precipitation-strengthened copper alloy material suitable for current-carrying members such as connectors, lead frames, relays and switches, and more particularly to a copper alloy material with improved conductivity, strength and bending workability, and a method for producing the same. .

  Electrical components such as connectors, lead frames, relays, and switches that make up electrical and electronic components are required to have good “conductivity” in order to suppress the generation of Joule heat due to energization. Therefore, “strength” that can withstand the stress applied during assembly and operation is required. Conventionally, materials having good “conductivity” or “strength” are appropriately selected and used for such energized parts depending on applications.

  However, in recent years, electrical and electronic parts have been highly integrated, miniaturized, and lightened, and accordingly, there is an increasing demand for thinning of energized parts. In applications where strength is important, a tensile strength of 850 MPa or more may be desired. On the other hand, it is desirable to maintain a tensile strength of 700 MPa or more even in applications requiring high conductivity such as 45% IACS or more or even 50% IACS or more. In order to cope with the miniaturization of electric / electronic parts, it is extremely advantageous to increase the degree of design freedom. To that end, it is essential to improve the “workability” of the current-carrying parts. It is also important that the lead frame material has excellent bending workability. However, there is a trade-off relationship between “strength” and “workability” or “strength” and “conductivity”, and it is generally not easy to improve these characteristics at the same time.

  Examples of the strengthening mechanism of the copper alloy include “solid solution strengthening”, “precipitation strengthening”, “work hardening”, and “fine grain strengthening (grain boundary strengthening)”. Among these, “solid solution strengthening” and “work hardening” tend to cause a decrease in conductivity and workability. It is advantageous to use “precipitation strengthening” to achieve high strength while maintaining the conductivity of the copper alloy at a high level.

  Conventionally, Cu-Cr (-Zr) -based, Cu-Fe-P-based, Cu-Mg-P-based, Cu-Ni-Si-based alloys and the like have been put to practical use as precipitation strengthened copper alloys. Among these, a Cu—Ni—Si alloy (so-called Corson alloy) has recently attracted attention as an alloy having an excellent balance between strength and conductivity.

  However, in order to fully exploit the properties of precipitation-strengthened copper alloys, many manufacturing processes including “solution treatment” and “aging treatment” are required, and the manufacturing conditions in each process must be strictly controlled. The current situation is not. This inevitably increases the manufacturing cost. Specifically, the steps of hot rolling, cold rolling, solution treatment (or intermediate annealing), cold rolling, aging treatment, finish rolling, and low temperature annealing are generally taken. Furthermore, if necessary, multiple heat treatments (solution treatment, annealing, aging, etc.) may be employed, or heat treatment and cold rolling may be repeated.

  The “solution treatment” required for the production of precipitation-strengthened copper alloys is a process in which the alloy is heated and held above the solid solution limit temperature of the precipitate and then rapidly cooled to form a supersaturated solid solution. Need to manage. That is, when the solution temperature is low, recrystallization does not occur or occurs partially, so that a uniform recrystallization structure cannot be obtained. In addition, the amount of the precipitated element dissolved in the Cu matrix decreases, and it becomes difficult to sufficiently generate the precipitate. On the other hand, when the solution temperature is high, the crystal grains are likely to become coarse in a short time, and it becomes difficult to stably improve the bending workability of the final product. In other words, the solution treatment conditions must be controlled within a narrow range, and if they deviate even a little, the characteristic variation tends to increase. In addition, a rapid cooling operation is usually required in the solution treatment. Therefore, in order to perform a stable solution treatment operation at a mass production site, it is necessary to provide a large dedicated furnace capable of advanced condition control.

  The “aging treatment” necessary for the production of the precipitation strengthened copper alloy is a step in which the alloy after the solution treatment is heated and held at an appropriate temperature below the solid solution limit temperature to generate a precipitation phase. When the aging treatment temperature is low, the time required to sufficiently advance the precipitation becomes long, and the productivity is lowered. When the aging treatment temperature is high, or when cold working at a large working rate is performed before the aging treatment, the heating time can be shortened, but on the other hand, the precipitates are likely to be coarsened and the strength is lowered. Therefore, advanced condition management is also required for the aging treatment, which contributes to an increase in manufacturing cost.

  In the case of a Cu-Ni-Si alloy, when the conventional solution treatment, cold rolling, and aging treatment are used, the strength increases with the passage of aging time and monotonously after a certain peak point. (I.e., an over-aged state of coarse precipitates). If an attempt is made to obtain a high tensile strength of about 700 MPa, the conductivity will drop to a level of 30-40% IACS, and conversely, if an attempt is made to raise the conductivity to 50% IACS or more, the tensile strength will drop to 650 MPa or less. . In other words, it is practically impossible to achieve high strength (for example, tensile strength of 700 MPa or more) while maintaining high conductivity (for example, 45% IACS or more or 50% IACS or more) simply by using “precipitation strengthening”. Is possible. Further, when cold rolling and low-temperature annealing are further performed after the aging treatment, the strength can be slightly improved, but the bending workability may be lowered.

  Patent Document 1 discloses a method of manufacturing a thin slab by cold rolling and aging treatment as a technique for reducing the manufacturing process of a Cu—Ni—Si alloy. However, although conductivity of 50-60% IACS is obtained, the hardness in that case is limited to about 200-140 HV (estimated tensile strength 650-450 MPa).

  Patent Document 2 discloses a multiple aging treatment method as a method for simultaneously improving the conductivity and strength of a Cu-Ni-Si alloy. Patent Document 3 discloses a method of repeating cold rolling and aging treatment. However, no consideration is given to improving the workability at the same time. Moreover, it cannot be said that it is advantageous in terms of cost due to the increased number of processes.

  On the other hand, if “fine grain strengthening (grain boundary strengthening)” by refining crystal grains is used, it is expected that the strength can be improved without impairing the electrical conductivity and the workability can be improved. However, in the grain refinement method by the usual thermomechanical processing method (cold rolling + recrystallization annealing), in the case of copper and copper alloy, it is generally limited to refinement to a crystal grain size of about several μm. This results in insufficient strength and processability.

  Therefore, recently, research for refining crystal grains by intense cold processing is underway. According to strong processing, the crystal grain size of the copper alloy can be reduced to 1 μm or less. The mechanism is explained as follows. That is, a large amount of dislocation is introduced by strong deformation, and a dislocation cell is formed by mutual entanglement of the dislocation. The higher the density of dislocations introduced, the smaller the size of the dislocation cells. While dislocation cells change to subgrains due to dynamic recovery, the orientation difference between the subgrains increases. When the misorientation is about 15 ° or more, the sub-crystal grains become in-situ crystal grains.

In this case, since the recrystallized grains are generated by continuously increasing the orientation difference of the sub-crystal grains, such a recrystallization phenomenon is called “continuous recrystallization”. The recrystallized grains have the same size as the sub-crystal grains and can be refined to 1 μm or less.
On the other hand, in the normal recrystallization mechanism that occurs in recrystallization annealing after cold rolling, etc., the sub-crystal grains grow as themselves as nuclei, and become recrystallized grains that have an orientation difference with the growth. This phenomenon of recrystallization is called “discontinuous recrystallization”. In this case, the recrystallized grains have a size at least several times larger than the sub-crystal grains, and the limit is that the recrystallized grains can be substantially reduced to about 2 to 3 μm. In the present specification, simply “recrystallization” means ordinary “discontinuous recrystallization”.

  Patent Document 4 discloses a technique for refining the crystal grain size of a copper alloy to 1 μm or less by strong processing of 95% or more. According to this method, in the case of a Cu—Ni—Si based alloy, a tensile strength of 800 MPa or more is obtained with a conductivity of less than 50% IACS. However, in addition to a process for performing strong processing, a solution treatment process and an aging process are also required, and an increase in manufacturing cost is inevitable. Further, according to the study by the inventors, the structure obtained by such strong working tends to be a “mixed grain structure” in which large crystal grains are mixed, and it is difficult to obtain bending workability with little anisotropy. .

JP-A-9-176808 JP-A-10-152737 JP 7-41887 A JP 2002-356728 A

  As described above, the conductivity, strength, and workability of the copper alloy material can be improved at the same time using any of the conventionally known methods such as solid solution strengthening, precipitation strengthening, work hardening, and fine grain strengthening (grain boundary strengthening). It is difficult to improve in a balanced manner. In addition, when precipitation-strengthened copper alloys are used, it is possible to increase the strength without significantly reducing the electrical conductivity, but it is inevitable that the cost will increase due to increased processes and strict management of manufacturing conditions. Currently.

  Therefore, the present invention aims to achieve improvements in conductivity, strength, workability, and simplification of the process at the same time in the manufacture of copper alloy materials suitable for current-carrying parts such as connectors, lead frames, relays, and switches. And

  As a result of various studies, the inventors have improved the conductivity, strength, and workability in a balanced manner by the synergistic action of precipitation strengthening and fine grain strengthening when combining "precipitation strengthened copper alloy" and "warm processing". I found out that it would be possible. At this time, the solution treatment process and the cold working process can be omitted, and the process can be simplified. The present invention has been completed based on such findings.

That is, the above object is characterized in that in the production of a precipitation-strengthened copper alloy material, after hot working, it is heated to a temperature lower than the recrystallization temperature and warm worked to obtain a structure having an average crystal grain size of 1 μm or less. This is achieved by a method for producing a copper alloy material. It is not necessary to perform solution treatment before warm working. Warm working can be performed at a working rate of 85% or more, and it is particularly preferable to perform warm working in a temperature range including an aging precipitation temperature range. In addition, heat treatment (low temperature annealing) can be performed at a temperature lower than the recrystallization temperature after warm working.
Here, the precipitation-strengthened copper alloy is a type of copper alloy that can generate an aging precipitate and thereby obtain a strength improving action.

The ultrafine crystal grain structure having an average crystal grain size of 1 μm or less can be confirmed by, for example, a scanning electron microscope (SEM), a transmission electron microscope (TEM), or an electron backscatter diffraction image (EBSP).
Warm processing is processing performed by heating to a temperature range lower than the recrystallization temperature, and is distinguished from these processing in that the temperature is higher than cold processing and lower than hot processing.

The present invention is directed to a Cu—Ni—Si alloy having the following composition .
In mass%, Ni: 1.0 ~ 3.5% preferably 2.48~3.20%, Si: 0.1~1.2%, Mg: 0~0.3%, Sn: 0~ 0.25% , Zn : 0 to 0.8% , Co : 0 to 0.16% , Cr : 0 to 0.10% , P : 0 to 0.02% , B : 0 to 0.005% , Al : 0 to 0.12% , Fe : 0 to 0.16% , Zr : 0 to 0.03% , Ti : 0 to 0.08% , Mn : 0 to 0.14% , balance Cu and inevitable Copper alloy consisting of impurities.
Here, “0%” of the lower limit of the element content is when the content of the element (or the total content of the elements belonging to the element group) falls below the measurement limit in a general copper alloy analysis technique. is there.

In the Cu-Ni-Si-based alloy, warm working is performed at a temperature of 600 ° C or lower. In that case, it is possible to include processing in an aging precipitation temperature range of at least 300 to 600 ° C, and it is preferable to control the warm processing temperature in the range of 250 to 600 ° C. After the warm working, heat treatment (low temperature annealing) can be performed at a temperature of 550 ° C. or less, preferably 250 to 550 ° C.

According to the present invention, a high-strength copper alloy material having a tensile strength of 850 MPa or more, or an electrical conductivity of 45, without performing solution treatment or aging treatment, which is a factor that increases the cost of conventional precipitation strengthened copper alloys. It has become possible to provide a copper alloy material having an excellent property balance of% IACS or more, or even 50% IACS or more, a tensile strength of 700 MPa or more, and an elongation of 5% or more. In particular, the anisotropy of bending workability was remarkably improved in the latter case. In addition, since the manufacturing method of the present invention uses warm processing, the equipment burden is reduced compared to the conventional method requiring strong cold processing, and implementation is relatively easy.
Therefore, the present invention can meet the needs for miniaturization and thinning of electric / electronic parts, which are expected to be further developed in the future, by providing materials for energizing parts such as connectors, lead frames, relays and switches.

“Precipitation strengthened copper alloy” can be used as a material for solving the above problems . In particular, an alloy in which aging precipitation occurs in a temperature range below the recrystallization temperature (that is, a warm processing temperature range) is a suitable target. For example, a Cu-Cr (-Zr) system, a Cu-Fe-P system, a Cu-Mg-P system, a Cu-Ni-Si system (the subject of the present invention), etc. can be employed. Melting of these alloys can be performed by a general method.

  First, the slab is subjected to hot working so that the crystallization phase generated in the casting process disappears, and at the same time, the cast structure is destroyed by recrystallization to make the recrystallized grain structure uniform. This hot working is desirably performed in the solid solution temperature range of the precipitate. And it is desirable to quench immediately by the water cooling etc. immediately after completion | finish of hot processing. By such treatment, a supersaturated solid solution can be produced, and the role of solution treatment can be simultaneously performed.

  The crystal grain size after hot working is desirably adjusted to 35 μm or less, preferably 15 μm or less. When the crystal grain size after hot working becomes large, the condition control range of warm working in the subsequent process becomes narrow. The crystal grain size can be controlled by the rolling reduction and processing temperature. Care must be taken when the hot finishing temperature is high or the processing rate is low because the crystal grains are likely to be large. The hot working rate may be approximately 65% or more in terms of the cross-sectional reduction rate. It is necessary to adjust the hot working rate so that a desired working rate can be ensured by warm working in the subsequent process. After hot working, chamfering or pickling can be performed as necessary.

  Subsequently, warm processing is performed. Warm processing is processing performed by heating to a temperature range below the recrystallization temperature. It is desirable to perform part or all of the warm working in the aging precipitation temperature range. By performing warm working in the aging precipitation temperature range, fine and uniform precipitates are formed using dislocations and vacancies continuously introduced during the processing as precipitation sites, and the growth of the precipitates is suppressed. Such a precipitation form is advantageous for simultaneous improvement of conductivity and strength. In this warm working, the introduction of dislocations and dynamic recrystallization occur simultaneously, resulting in dynamic “continuous recrystallization” and a thermally stable, average grain with a well-recovered sharp grain boundary. An ultrafine crystal grain structure having a diameter of 1 μm or less is formed very uniformly. As a result, remarkable “fine grain reinforcement” is realized. Further, the homogenization of the structure also works to reduce anisotropy. Such a structural state cannot be obtained by cold strong working.

  The warm working rate is preferably 85% or more in terms of the cross-sectional reduction rate. If the processing rate is lower than that, the formation of ultrafine crystal grains tends to be insufficient, and it is difficult to obtain good workability (for example, bending workability). In addition, when the temperature is lowered during warm working, dynamic “continuous recrystallization” is less likely to occur, and the cold working factor becomes stronger. The temperature drop during the warm working can be tolerated to about 80 ° C., but it is desirable to finish all the warm working in a temperature range of 200 ° C. or higher if possible. In order to prevent a temperature drop during the warm working, a method of putting the material in a furnace during the working and performing intermediate heating can be employed. In order to sufficiently obtain the effect of the above-described warm working, it is desirable to ensure a working rate (cross-sectional reduction rate) of 50% or more in the aging precipitation temperature range. It is more preferable to perform all the warm working in the aging precipitation temperature range.

  Next, heat treatment (low temperature annealing) is performed in a temperature range below the recrystallization temperature as necessary. Residual dislocations that do not contribute to the formation of ultrafine grain boundaries can be removed by this heat treatment, and conductivity and workability can be further improved. When the heating temperature is set to the aging precipitation temperature range, the precipitation of elements that are still supersaturated in the matrix proceeds, which is further advantageous in improving the conductivity and workability. Since these effects are difficult to obtain if the heating temperature is too low, it is preferably about 200 ° C. or higher, more preferably 250 ° C. or higher and lower than the recrystallization temperature. Although the heating time should be secured for at least 30 seconds or more, heating for too long is uneconomical and usually within 8 hours is sufficient.

Hereinafter, manufacturing conditions in the case of using a Cu—Ni—Si alloy which is a copper alloy of the present invention will be described.
[Chemical composition]
When Ni and Si are added in combination, the solid solution amount of Ni and Si decreases with the precipitation of Ni and Si compounds (hereinafter referred to as "Ni-Si system precipitates"), resulting in high conductivity. This is advantageous for improving the strength while maintaining the strength. In particular, when warm working is performed in the precipitation temperature range of Ni-Si based precipitates, the precipitates precipitated during warm working increase the density of dislocations introduced by warm working and form ultrafine crystal grains. On the other hand, the processing in the precipitation process exerts the effect of preventing coarsening while further generating precipitates. In other words, the combined addition of Ni and Si improves the electrical conductivity and strength by aging precipitation in combination with warm working, and improves the strength and workability (for example, bending workability) by ultra-fine crystal grains. Bring.

When the Ni content is less than 0.4% by mass or the Si content is less than 0.1% by mass, it is difficult to effectively bring out the above effects. On the other hand, if the Ni content exceeds 4.8% by mass or the Si content exceeds 1.2% by mass, the electrical conductivity decreases (because the precipitate tends to coarsen) and the strength tends to decrease. Moreover, warm workability falls. Therefore, it is desirable that the Ni content is 0.4 to 4.8% by mass and the Si content is 0.1 to 1.2% by mass. In the present invention, the Ni content is 1.0 to 3.5% by mass . A more preferable Si content is 0.2 to 0.8% by mass.

  The mass ratio of Ni and Si (Ni / Si) is preferably in the range of 3.5 to 6.0. Outside this range, the solid solution amount of Ni or Si that was not used for the formation of Ni—Si-based precipitates increases, and the conductivity may decrease. A more preferable range of Ni / Si is 4.0 to 5.5.

  Mg has the effect of preventing the coarsening of Ni—Si system precipitates. It also has an effect of improving stress relaxation resistance. In order to fully exhibit these actions, it is desirable to ensure an Mg content of 0.01% by mass or more. However, if the Mg content exceeds 0.3% by mass, the castability and hot workability are remarkably lowered, and the cost is disadvantageous. For this reason, when adding Mg, it should carry out in the range of 0.3 mass% or less. The range of more preferable Mg content is 0.05-0.2 mass%.

  The remainder other than Ni and Si, or the remainder other than Ni, Si and Mg may be composed of Cu and inevitable impurities. However, other alloy elements may be added as necessary. For example, Sn, Zn, Co, Cr, P, B, Al, Fe, Zr, Ti, and Mn have the effect of further increasing the alloy strength and reducing the stress relaxation. It also improves warm workability and further promotes the formation of ultrafine grains. Co, Cr, B, Zr, Ti, and Mn can easily form a high melting point compound with S, Pb, and the like that are unavoidable impurities, and can contribute to improvement of hot workability. Sn and Zn have the effect of improving cold workability.

  When one or more of these elements are added, it is desirable to add so that the total amount becomes 0.01% by mass or more in order to sufficiently obtain the action. However, when the total amount exceeds 3% by mass, hot work, warm work or cold workability may be deteriorated. It is also economically disadvantageous. Accordingly, the total amount is preferably in the range of 3% by mass or less, more preferably in the range of 2% by mass or less, still more preferably in the range of 1% by mass or less, and still more preferably in the range of 0.5% by mass or less. .

In the present invention, the following alloy composition is adopted .
In mass%, Ni: 1.0 ~ 3.5% preferably 2.48~3.20%, Si: 0.1~1.2%, Mg: 0~0.3%, Sn: 0~ 0.25% , Zn : 0 to 0.8% , Co : 0 to 0.16% , Cr : 0 to 0.10% , P : 0 to 0.02% , B : 0 to 0.005% , Al : 0 to 0.12% , Fe : 0 to 0.16% , Zr : 0 to 0.03% , Ti : 0 to 0.08% , Mn : 0 to 0.14% , balance Cu and inevitable impurities.

[Hot processing]
When hot rolling the above Cu-Ni-Si alloy, hot cracking tends to occur due to the formation of coarse Ni and Si compounds in the temperature range below 650 ° C, so hot rolling in the range of 950-650 ° C. It is preferable to perform water cooling after the final pass. The hot rolling rate may be approximately 65 to 95%.

(Warm rolling)
When warm-rolling the Cu—Ni—Si alloy, the heating extraction temperature is preferably 600 ° C. or less. In the temperature range exceeding 600 ° C., the crystal grains are likely to be coarsened due to the occurrence of normal discontinuous recrystallization, and cracking due to the formation of coarse Ni and Si compounds is likely to occur. Although the temperature drop during warm rolling can be tolerated to about 80 ° C., it is desirable to obtain a reduction rate of 50% or more in the aging precipitation temperature range of 300 to 600 ° C. If possible, it is desirable to perform all rolling passes at 250 ° C. or higher. More preferably, the entire rolling pass is performed between 250 and 600 ° C, more preferably between 250 and 550 ° C. In order to prevent a temperature drop during warm rolling, the plate may be placed in a furnace in the middle and reheated. A rolling mill equipped with a winding heating furnace can be suitably used. The warm rolling rate is preferably 80% or more. 85% or more is more preferable.

[Heat treatment (low temperature annealing)]
The Cu—Ni—Si based alloy after the warm rolling can be heat-treated at a temperature range of 550 ° C. or less as necessary. If it exceeds 550 ° C., it softens in a short time, and variations in characteristics are likely to occur in both batch and continuous systems. However, if the heating temperature is too low, it takes a long time to control the grain boundaries, which is uneconomical. It is still more preferable to set it as 350 degreeC or more. It is desirable to secure a heating time of 30 seconds or longer. Usually, the conductivity and workability can be sufficiently improved within a range of 3 hours or less.

  The copper alloys shown in Table 1 were melted and cast using a vertical small continuous casting machine. The cross-sectional dimension of the slab is 35 × 70 mm.

Each slab was heated to 950 ° C., hot-rolled to a thickness of 3 to 12 mm in a temperature range of 950 to 700 ° C., and then rapidly cooled (water cooled). The crystal grain size after hot rolling was 35 μm or less.
Next, except for some comparative examples, finish rolling was performed to a thickness of 0.25 mm under the conditions shown in Table 2. In Table 2, what is described as “normal temperature” in the column of finish rolling temperature is cold-rolled. What indicated temperature other than that is what performed warm rolling, and the temperature of description is heating temperature. In the warm rolling, the entire rolling pass was performed in the range of the heating temperature to 250 ° C. Intermediate heating was performed between intermediate passes as necessary so that the rolling temperature did not fall below 250 ° C. The intermediate heating temperature is the same as the initial heating temperature.
After that, some were further annealed at the temperatures and times shown in Table 2.
For comparison, some materials were subjected to solution treatment and aging treatment after hot rolling, and warm rolling was not performed.

  From the final process finished material (aging-treated material, cold-rolled material, warm-rolled material or low-temperature annealed material) obtained in this way, a sample for metallographic structure observation, a sample for conductivity measurement, a tensile test piece, hardness measurement Samples for bending and test pieces for bending workability were collected.

The metal structure observation was performed using a scanning electron microscope (magnification 500 to 10000 times) for a cross section perpendicular to the thickness direction of the rolled sheet. The average crystal grain size was determined by the cutting method of JIS H0501 in the observation field.
The conductivity was measured according to JIS H0505.
The tensile test was performed according to JIS Z2241 using a test piece parallel to the rolling direction, and the tensile strength and elongation at break were determined.
The hardness was measured according to JIS Z2244 for the surface of the rolled plate, and the Vickers hardness was determined.

Bending workability is 90 ° W bending test (based on JIS H3110, plate thickness t = 0.25 mm, width when the bending axis is perpendicular to the rolling direction (GW) and parallel (BW). W = 10 mm) was performed, and the surface and cross section of the bent portion were observed with an optical microscope at a magnification of 100 times, and the minimum R / t at which no crack was generated was determined and evaluated. Here, R is the inner bending radius, and t is the plate thickness. The smaller the minimum R / t, the better the bending workability.
Table 2 shows the manufacturing conditions for each step, and Table 3 shows the test results.

  As can be seen from Tables 1 to 3, the warm rolled materials of Nos. 1 to 5 in the examples of the present invention have a high tensile strength of 850 MPa or more, and are optimal for current-carrying parts that emphasize high strength like IC lead frame materials. It is. The low temperature annealing materials of Invention Examples No. 6 to 10 sufficiently cleared the electrical conductivity of 45% IACS or higher, the tensile strength of 700 MPa or higher, and the elongation of 5% or higher. The bending workability also cleared the minimum R / t 1.0 or less, and the anisotropy of bending workability was also improved. That is, a material having improved conductivity and strength and workability at a high level in a well-balanced manner was obtained.

  On the other hand, Nos. 21 and 22 of the comparative examples had a low Ni content in the Cu—Ni—Si based alloy, so the amount of precipitates was small, and it was not possible to achieve ultrafineness by warm rolling. As a result, the tensile strength and bending workability were inferior. On the contrary, in No. 23, since the Ni and Si contents were too high, the precipitates were coarsened, and the ultrafine grains once formed grew and normal discontinuous recrystallization occurred. As a result, strength and bending workability were poor. In No. 24, since the Ni and Si contents were too high, severe cracks occurred during warm rolling, and the final characteristics could not be evaluated.

  Nos. 25 to 28 are manufactured using a hot-rolled material of alloy B, subjected to solution treatment, cold rolling, and aging treatment, and without being hot-worked (conventional process materials). Of these, Nos. 25 to 27 are materials that have been subjected to aging treatment, and it can be seen that the electrical conductivity and strength are in a trade-off relationship depending on the aging time. That is, in these, the electrical conductivity and strength could not be simultaneously improved to a high level. No. 28 was further subjected to cold rolling and low temperature annealing, but the strength was low.

  Nos. 29 and 30 were obtained by performing hot rolling under a cold strong pressure using a hot rolled material of alloy B, but with a mixed grain structure in which ultrafine grains were partially formed, resulting in poor workability. It was. Nos. 31 and 32 are obtained by warm rolling the hot rolled material of alloy B. However, because the warm rolling rate was too low, the formation of ultrafine grains was reduced, resulting in a mixed grain structure, workability or further conductivity. Inferior to

Claims (7)

  In mass%, Ni: 1.0 to 3.5%, Si: 0.1 to 1.2%, Mg: 0 to 0.3%, Sn: 0 to 0.25%, Zn: 0 to 0.3. 8%, Co: 0 to 0.16%, Cr: 0 to 0.10%, P: 0 to 0.02%, B: 0 to 0.005%, Al: 0 to 0.12%, Fe: In the production of a copper alloy material comprising 0 to 0.16%, Zr: 0 to 0.03%, Ti: 0 to 0.08%, Mn: 0 to 0.14%, the balance Cu and unavoidable impurities, A method for producing a copper alloy material, characterized in that after hot working, the hot working is performed at a temperature of 600 ° C. or lower to obtain a structure having an average crystal grain size of 1 μm or less.   In mass%, Ni: 2.48 to 3.20%, Si: 0.1 to 1.2%, Mg: 0 to 0.3%, Sn: 0 to 0.25%, Zn: 0 to 0.3. 8%, Co: 0 to 0.16%, Cr: 0 to 0.10%, P: 0 to 0.02%, B: 0 to 0.005%, Al: 0 to 0.12%, Fe: In the production of a copper alloy material comprising 0 to 0.16%, Zr: 0 to 0.03%, Ti: 0 to 0.08%, Mn: 0 to 0.14%, the balance Cu and unavoidable impurities, A method for producing a copper alloy material, characterized in that after hot working, the hot working is performed at a temperature of 600 ° C. or lower to obtain a structure having an average crystal grain size of 1 μm or less.   Furthermore, the manufacturing method of the copper alloy material of Claim 1 or 2 which heat-processes at the temperature of 550 degrees C or less after warm processing.   The method for producing a copper alloy material according to any one of claims 1 to 3, which includes processing in a temperature range of at least 300 to 600 ° C in warm processing.   The method for producing a copper alloy material according to any one of claims 1 to 3, wherein the warm working is performed in a range of 250 to 600 ° C.   The method for producing a copper alloy material according to any one of claims 1 to 3, wherein the warm working is performed at a working rate of 85% or more.   The manufacturing method of the copper alloy material of Claim 3 which performs the heat processing after a warm process in 250-550 degreeC.