JP2008223069A - High-strength, high-conductivity copper alloy and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an inexpensive high-strength, high-conductivity copper alloy in which mechanical strengths represented by tensile strength and hardness are improved to values higher than those in JIS Z 3234 type III standard without deteriorating physical properties and the additive quantity of expensive Ni is reduced and which is free of Be and has ≥820 N/mm<SP>2</SP>tensile strength, ≥244 hardness by HB (10/3000) and ≥35% IACS electrical conductivity. <P>SOLUTION: This copper alloy has a composition which consists of, by weight, 3.30 to 6.0% Ni, 0.8 to 1.7% Si, 0.5 to 1.5% Cr, 0.1 to 0.3% Sn and the balance Cu excluding inevitable impurities and in which the value of Ni/Si by weight ratio ranges from 3 to 4. The copper alloy has ≥820 N/mm<SP>2</SP>tensile strength, ≥244 hardness by HB (10/3000) and ≥35% IACS electrical conductivity. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a copper alloy electrode material for resistance welding that requires mechanical strength, electrical conductivity, and heat resistance, and related jigs, sliding that requires thermal conductivity and wear resistance utilizing chrome silicide / nickel silicide. The present invention relates to a high-strength, high-conductivity copper alloy that requires mechanical strength, thermal conductivity, and heat resistance, and a method for producing the same.

  In recent years, as a JIS Z 3234 type 3 standard product that is a standard for resistance-welding copper alloy electrode materials, as shown in Patent Document 1, an electrode material that does not contain Be, which is harmful, has been developed. This material is used not only for electrode materials but also for sliding members because the silicide formed in the matrix of the alloy acts to lower the friction coefficient, and also has good heat resistance and thermal conductivity. It is also used for machine parts that require heat resistance and good thermal conductivity.

  However, since the material described in Patent Document 1 contains only Ni up to 3%, there is a limit to the mechanical strength expressed by tensile strength and hardness. Therefore, as a material superior in mechanical strength to the material described in Patent Document 1, a BeCu25 alloy is generally mainly used as a bulk material.

  The BeCu25 alloy is used, for example, in a resistance welding gun arm assembled to a robot. This gun arm is not suitable as a resistance-welding gun arm to be assembled to a robot, even if it has a slightly lower electrical conductivity than JIS Z 3234 Type 3 standard product, unless it is a high strength material. Further, this BeCu25 alloy has good thermal conductivity and mechanical properties, so that it is used not only as a mold part for plastic molding but also as a die-cast plunger tip.

  Moreover, since the BeCu25 alloy contains Be, there is a concern that it adversely affects the human body and the environment. Therefore, when the copper alloy described in Patent Document 1 that does not contain Be is used as a mold part for plastic molding, the hardness is insufficient and the hardness of HB (10/3000) is 244 or higher, or the Rockwell hardness HRC is 24 or higher. Can't meet. For these reasons, there is a demand for a material that is Be-free and has excellent mechanical strength and thermal conductivity when used as a die part or a resistance welding gun arm to be assembled to a robot.

The presence of the copper alloy described in Patent Document 2 is known as a material that satisfies the above-mentioned requirements, has excellent mechanical strength, and does not contain Be. The copper alloy described in Patent Document 2 has a Ni content of 8.5 wt% to 11.5 wt%, a Ni / Si weight ratio of 3.4 to 4.5, and Cr of 0.50 wt% as shown in the examples. ˜2.00 wt%, the balance being made of Cu, having a hardness of Rockwell C30 or higher and a conductivity of IACS of 24% or higher.
Japanese Patent No. 356311 JP-A-4-247839

  However, the copper alloy described in Patent Document 2 contains 8.5 wt% to 11.5 wt% of expensive Ni and has a Ni / Si weight ratio of 3.4 to 4.5. In this case, the amount of silicide formed in the matrix increases, cracking due to internal stress is likely to occur during the heat treatment, and hot plastic working is difficult.

The present invention is intended to solve the above-described problems, and improves the tensile strength and hardness expressed as mechanical strength over the JIS Z 3234 Type 3 standard product without impairing physical properties. In addition, the amount of expensive Ni added is suppressed, Be-free, tensile strength is 820 N / mm ² or more, hardness is 244 or more for HB (10/3000), and conductivity is 35% or more for IACS. It is intended to obtain a conductive and inexpensive copper alloy.

In order to solve the above-described problems, the first invention of the present application is Ni 3.30 to 6.0 wt%, Si 0.8 to 1.7 wt%, Cr 0.5 to 1.5 wt%, Sn 0.1 to 0.3 wt%. %, The balance is made of Cu excluding inevitable impurities, the Ni / Si weight ratio is 3 to 4, the tensile strength is 820 N / mm ² or more, and the hardness is HB (10/3000) 244 or more and conductivity is 35% or more in IACS.

In addition, the second invention of the present application contains Ni 3.30 to 6.0 wt%, Si 0.8 to 1.7 wt%, Cr 0.5 to 1.5 wt%, Sn 0.1 to 0.3 wt%, and Mg , One or both of Mn are contained in an amount of 0.01 to 0.1 wt%, and the balance is made of Cu excluding inevitable impurities, the Ni / Si weight ratio is 3 to 4, and the tensile strength Is 820 N / mm ² or more, the hardness is 244 or more in HB (10/3000), and the conductivity is 35% or more in IACS. Mg and Mn are both used as an oxide generation inhibitor in the matrix.

The third invention of the present application contains Ni 3.30 to 6.0 wt%, Si 0.8 to 1.7 wt%, Cr 0.5 to 1.5 wt%, Sn 0.1 to 0.3 wt%, and the balance Is made of Cu excluding unavoidable impurities, and after a solution treatment of a copper alloy having a Ni / Si weight ratio of 3 to 4 at a solution treatment temperature range of 850 ° C. to 950 ° C., the cold working rate is It is cold-worked to 10 to 40% of the cross-sectional area of the original material, and then subjected to an aging treatment at a treatment temperature of 400 to 500 ° C., with a tensile strength of 820 N / mm ² or more, hardness The HB (10/3000) is 244 or more, and the conductivity is IACS 35% or more.

The fourth invention of the present application contains Ni 3.30 to 6.0 wt%, Si 0.8 to 1.7 wt%, Cr 0.5 to 1.5 wt%, Sn 0.1 to 0.3 wt%, and Mg. A copper alloy containing 0.01 to 0.1 wt% of one or both of Mn and the balance being made of Cu excluding inevitable impurities and having a Ni / Si weight ratio of 3 to 4. After the solution treatment at a solution treatment temperature in the range of 850 ° C. to 950 ° C., the cold work is performed so that the cold work rate becomes 10 to 40% with respect to the cross-sectional area of the original material, and then the treatment temperature 400 It is manufactured by aging treatment at ˜500 ° C., tensile strength is 820 N / mm ² or more, hardness is 244 or more in HB (10/3000), and conductivity is 35% or more in IACS.

  The present invention is configured as described above, and the tensile strength and hardness expressed as mechanical strength can be expressed as JIS Z by suppressing the addition amount of expensive Ni and adjusting the addition amounts of Ni and Si. A high strength, high conductivity copper alloy with high mechanical strength and high electrical conductivity, without using Be, which is not harmful to the environment, without damaging the physical properties, while improving the 3234 type 3 standard product. It can be obtained inexpensively.

  The inventor increases the mechanical strength as compared with the material described in Patent Document 1 and has a conductivity close to this, and the addition of Ni is higher than that of a copper alloy having a high compounding ratio of expensive Ni described in Patent Document 2. The target standard for developing a copper alloy that is superior in tensile strength and hardness to the tensile strength and hardness of JIS Z 3234 type 3 standard, but also excellent in elongation and conductivity, while reducing the amount. Set. Further, the electrical conductivity tends to decrease when the tensile strength and hardness are good. Therefore, as a result of experiments on the material of the present invention having good tensile strength and hardness as described above, it has become clear that a conductivity of 35% or more can be secured. It was above.

Tensile strength 820N / mm ² or more
Hardness (HB (10/3000)) 244 or more
Conductivity (IACS) 35% or more In order to prevent damage to the product while maintaining good tensile strength and hardness as described above when used for products such as resistance welding gun arms to be assembled on robots, 7 It is desirable to achieve an elongation of at least%.

  Further, it has been found that Ni is the most important element as an additive element related to mechanical properties in producing the copper alloy described in Patent Document 1. Then, considering satisfying the above-mentioned target standard and not increasing the expensive Ni as much as possible, first, it was examined to contain 3.30 to 6.0 wt% of Ni. If the Ni content is less than 3.30 wt%, the target mechanical properties will not be obtained, and if it is more than 6.0 wt%, the amount of expensive Ni added will increase and the manufacturing cost will increase. In addition to the other additive elements, the hot plastic workability deteriorates and the internal stress strain in the heat treatment for precipitation hardening increases, so that cracking is likely to occur.

Next, Si combines with Ni to form a Ni silicide in the matrix, and when used as a sliding member at the same time as improving the strength, the friction coefficient can be lowered. Ni ₂ Si can be considered as a compound of Ni and Si. In addition, a little extra Si addition forms Cr silicide in addition to Ni silicide as a compound together with Cr described below, and contributes to precipitation strengthening and wear resistance. As a compound of Cr and Si, Cr ₅ Si ₃ or the like can be considered.

    As a result of considering the above, it is clear that the Ni / Si weight ratio is preferably 3 to 4 as the amount of Si added to Ni from the viewpoints of strength improvement, reduction of friction coefficient, precipitation strengthening, and wear resistance. became. If the Ni / Si weight ratio is less than 3, the toughness decreases and the tensile strength of mechanical properties decreases. Further, when the Ni / Si weight ratio is larger than 4, either Ni silicide or Cr silicide is insufficient, which affects precipitation strengthening, and when used as a bulk material, improvement in mechanical properties cannot be expected. .

    In addition, when Cr is added to the alloy of the present invention by atmospheric dissolution, since this Cr is most easily oxidized, attention must be paid to yield fluctuations. However, it has been found that if the content is within the following range, even if the yield rises or falls slightly, it does not matter much if the heat treatment of the precipitation strengthening method is not mistaken. Therefore, in the present invention, the Cr content is 0.5 to 1.5 wt%. And if content is less than 0.5 wt%, compound formation with Si will decrease, electrical conductivity will fall in relation to Ni addition amount, and it will not contribute to precipitation strengthening. On the other hand, when the content is more than 1.5%, the oxides increase to affect the material, and the material cost increases, which is uneconomical.

  Moreover, Sn improves the mechanical properties represented by tensile strength and hardness by promoting solid solution strengthening and forming a Cu-Sn compound. Since the rate is not lowered, it is important as an auxiliary additive element. Therefore, in the present invention, the Sn content is set to 0.1 wt% to 0.3 wt%. When the content is less than 0.1 wt%, the above effect is difficult to obtain. When the content is more than 0.3 wt%, the conductivity decreases due to the influence of other additive elements, and the target standard cannot be satisfied. Become.

Further, by adding a small amount of Mg and Mn as other additive elements, excess oxide is absorbed to form MgO ₂ and MnO ₂ , thereby suppressing generation of Cr oxides. In addition, the content of Mg and Mn is in the range of 0.01 wt% to 0.1 wt%, and if the content of Mg and Mn is less than 0.01 wt%, the molten metal is carefully dissolved and dissolved. Otherwise, the generation of Cr oxide cannot be suppressed. On the other hand, when the content is more than 0.1 wt%, the mechanical properties are deteriorated and the conductivity is also deteriorated. In addition, since the copper alloy of the present invention does not contain Be, which has harmful concerns, it is possible to obtain a safe product free from concerns such as Be fume even if severe cutting and welding are performed on this material. Become.

  Then, the above elements are melted without being oxidized as much as possible to make an ingot (however, vacuum melting is not necessary), and after the hot plastic working, the solid solution in the range of 850 to 950 ° C. is used. Cold work is performed on the cross-sectional area by 10 to 40%, and this cold work contributes to the improvement of tensile strength. Then, the target specification was able to be satisfied by performing an aging treatment at 400 ° C. to 500 ° C.

  Moreover, although the copper alloy of the present invention and the above processing method are originally intended for the production of bulk materials, it is also possible to produce a thin plate by rolling by adjusting the additive elements within the content range of the present invention. It is. In addition, when performing cold working, perform processing within 40% of the original cross-sectional area in one processing, and then perform processing heat treatment (processing that repeats annealing and cold rolling) before performing heat treatment, and then Apply solution treatment. After solution treatment, finish by removing surface oxides, perform cold working (cold working should be 10% or more), and process to a thin plate that satisfies the above target standards by applying aging treatment Can do.

  Each embodiment in the first to fourth inventions will be described in detail below. First, the component analysis values of each Example and Comparative Example are shown in Table 1 below. In addition, Example 1- Example 5 and Example 10 are Examples which made Ni content the value close | similar to the intermediate value of Ni content range (3.30-6.0 wt%) of this invention. In Examples 1 to 5, the Ni / Si weight ratio is close to the upper limit of the Ni / Si weight ratio range (3 to 4) of the present invention.

    In addition, Example 6 and Example 7 are examples in which the Ni content is a value close to the lower limit value, and Example 8 and Example 9 are values in which the Ni content is a value close to the upper limit value. . In Example 11, the Ni content was set to a value slightly lower than the intermediate value of the Ni content range of the present invention, and the Ni / Si weight ratio was the lower limit of the Ni / Si weight ratio range (3 to 4) of the present invention. The value is close to the value.

  Moreover, Comparative Examples 1-4 are copper alloys with more Ni content than an Example, and the comparative example 1 makes Ni / Si weight ratio lower than Comparative Examples 2-4. In addition, since the amount of silicide increases when the amount of Si added is increased, a small amount of Mg and Mn is added to suppress the generation of oxides and to ensure toughness.

    Further, Comparative Example 2 is composed of only four elements of Ni, Si, Cr, and Cu, and among these, the amount of Si is suppressed to be lower than that of Comparative Example 1. In Comparative Example 3, the mixing ratio of Ni, Si, and Cr is substantially the same as that in Comparative Example 2, and a small amount of Mg and Zn are further added. In Comparative Example 4, the addition amount of Ni and Cr is kept lower than those of Comparative Examples 1 to 3, and a small amount of Sn is added. Comparative Examples 5 to 9 are materials described in Patent Document 1 that have been commercially available, and are randomly extracted from mass-produced products. In Comparative Example 10, the content of each element of Ni, Si, Cr, Sn, and Cu is within the content range of the present invention, and the Ni / Si weight ratio is within the Ni / Si weight ratio range of the present invention. It is 4.40 which is higher than the upper limit.

  And in order to manufacture the samples of Examples 1-11 shown in Table 1, and Comparative Examples 1-10, Ni, Si, Cr, Sn, Mg, Mn, Zn, and Cu were prepared. Here, Ni was prepared as electrolytic Ni, Si as a Cu—Si (10%) master alloy, Cr as a Cu—Cr (10%) master alloy, and Sn as an electrolytic Sn. Further, Mg as a minor additive was prepared as a Cu—Mg (50%) master alloy, Mn as a Cu—Mn (30%) master alloy, and Zn as electrolytic Zn.

  Examples 1 to 11 and Comparative Examples 1 to 4 and 10 were prepared by preparing a total of 25 kg of raw material per charge. In Comparative Examples 5 to 9, samples were collected from 800 kg of product per charge.

  In Examples 1 to 11 and Comparative Examples 1 to 4 and 10, graphite crucibles were prepared, appropriate amounts of flux and charcoal were prepared in a high frequency furnace, and ingots were produced by the Darville method. Then, the outer periphery of the ingot was chamfered by machining to confirm that there was no scratch, and the next step was used. Then, it was forged to 40 mm by hot forging, dissolved at the solution temperature shown in Table 2 below, quickly cooled with water, and subjected to solution treatment. Thereafter, the outer periphery was chamfered to Φ37 mm, and was subjected to cold drawing and aging treatment steps. The aging temperature for each sample is shown in Table 2 below.

  In Comparative Examples 5 to 9, a Φ275 mm ingot was processed into Φ55 mm by hot extrusion, dissolved at the solution temperature shown in Table 2 and quickly cooled with water, and subjected to a solution treatment. Then, after performing a cold working to Φ40 mm through a polishing process, it was subjected to an aging treatment process and the like. And each material processed as mentioned above was cut | disconnected, the test piece which measures a JIS4 test piece and hardness and electrical conductivity was extract | collected, and it used for each test.

  The results of solution treatment, cold working, and aging treatment for each sample as described above will be described below. In Example 1, the tensile strength and hardness satisfied the target standard by slightly shortening the aging treatment time. In Example 2, the solution treatment temperature was set to 900 ° C., which is an intermediate between 850 ° C. and 950 ° C., and the aging treatment temperature was lowered by 10 ° C. compared to Example 1 to increase the aging treatment time. As a result, the tensile strength was somewhat reduced as compared with Example 1, but the conductivity was high.

    In Example 3, the solution treatment temperature was further lowered by 10 ° C. compared to Example 2 above, and the solution treatment time was lengthened. As a result, the tensile strength, 0.2% proof stress, and hardness decreased as compared with Example 1 and Example 2, but the elongation and conductivity exceeded those of Example 1 and Example 2. In Example 4, the cold working rate was lowered as compared with Examples 1 to 3 above, and the aging treatment temperature was increased by 10 ° C. from Example 1, and peak aging treatment was performed at the optimum temperature and optimum time. The peak aging treatment means that the aging treatment is performed at the optimum temperature and the optimum time in order to obtain the maximum strength of the material. As a result, the tensile strength, 0.2% proof stress, and hardness were higher than those in Example 3, and the conductivity was higher than that in Example 1.

  Further, in Example 5, the peak aging treatment was performed with the cold working rate somewhat lower than in Example 4. As a result, the elongation and hardness values did not increase so much, but the tensile strength was higher than those in Examples 2 and 3, and the 0.2% proof stress was higher than those in Examples 2 to 4. Further, the conductivity was higher than that of Example 1. Further, Example 6 is the same as the aging treatment conditions of Example 1 except that the addition amounts of Ni and Si are reduced and the cold working rate is the same as that of Example 5. Although the mechanical strength was slightly inferior to that of Example 1, the elongation and conductivity showed high values.

  Further, Example 7 is the same as the aging treatment conditions of Example 2 except that the addition amount of Ni and Si is reduced and the cold working rate is the same as that of Example 5. As a result, the tensile strength, 0.2% proof stress, and hardness were slightly decreased as compared with Example 2, but the elongation and conductivity were increased. Moreover, since Example 8 and Example 9 had much content of Ni and Si, the cold work rate was a limit of 15%. As a result, the elongation was low compared to Examples 2, 3, and 5-7, but the tensile strength was higher than that of Examples 2, 3, 6, and 7, and 0.2% proof stress. Was higher than those of Examples 2, 3, 6, and 7.

    Further, in Example 10, the Ni and Si contents are within the range of the Ni and Si content of the present invention, that is, Ni is 3.30 to 6.0 wt%, and Si is approximately an intermediate value of 0.8 to 1.7 wt%. In addition, a small amount of Mg and Mn are added. Mg and Mn serve as antioxidants, and by adding these, dissolution becomes easy and defects in the ingot are less likely to occur. The solution treatment temperature was set to 900 ° C., which is an intermediate value, and the aging treatment time was set slightly longer than the optimum aging treatment time.

    As a result, it has been clarified that the addition of Mg and Mn increases the additive elements of the copper alloy, but the mechanical properties and conductivity do not decrease. In addition, the solution treatment temperature of Corson-based alloy is not affected even if the temperature is not wrong, even if the time is slightly shifted, the effect on the mechanical properties and conductivity is slight, but regarding the aging treatment, the mechanical properties depend on the temperature and time. In addition, it is a material having a great influence on conductivity.

  In Example 11, the Ni / Si weight ratio was set to 3.13 close to the lower limit of the Ni / Si weight ratio of the present invention as described above, and the cold working rate and heat treatment conditions were the same as in Example 6. It is what. The heat treatment conditions refer to solution treatment temperature, solution treatment time, aging treatment temperature, aging treatment time, and the like. As a result, the elongation was close to the lower limit value of the target standard, but the target standard was sufficiently satisfied with respect to tensile strength, hardness, and conductivity. From the above results, in Examples 1 to 11, the mechanical strength, elongation, and conductivity values all exceeded the mechanical strength, elongation, and conductivity values listed above as target standards. .

  Next, the result of the comparative example will be described below. In addition, the solution treatment temperature of Comparative Examples 1 to 10 was 920 ° C., which was able to obtain good values particularly in tensile strength, 0.2% proof stress, and elongation from the results of Examples 1 to 4 above. did. Moreover, since Comparative Examples 1-4 was high in hardness, it was not possible to perform cold working. Moreover, about the aging treatment temperature of Comparative Examples 1-4, it was set as 470 degreeC-480 degreeC based on the description of the patent document 2. FIG.

  As a result, as shown in Table 2, in Comparative Examples 1 to 3, the tensile strength and the 0.2% proof stress were good, but the conductivity could not achieve the target standard. Moreover, Comparative Examples 1 and 2 could not achieve the target standard for elongation. Further, the hardness was almost the same as that in each of the above-described examples, but this seems to be somewhat related to the relationship between the aging treatment temperature and the absence of cold working.

    Moreover, the comparative example 4 tried what made content of Ni low compared with Comparative Examples 1-3. However, it was not cracked until the solution treatment, but cracking due to internal stress was found after the aging treatment because of a problem in hot working. Therefore, measurement about tensile strength, 0.2% proof stress, and elongation could not be performed. In addition, since hot working of a product with a high Ni content is difficult, attempts were made by adding a small amount of Mg, Mn, and Zn, respectively, but the elongation and conductivity could not reach this target standard.

  In addition, Comparative Examples 5 to 9 are all mass-produced and can be produced without problems. However, since the addition amounts of Ni and Si are lower than those of the present example, it is natural that although the electrical conductivity and elongation are high, the tensile strength and hardness do not reach the target standards.

  In Comparative Example 10, the content of Ni, Si, Cr, and Sn was within the content range of the present invention, and the cold working rate and heat treatment conditions were the same as in Example 6, but the Ni / Si weight ratio The mechanical properties other than elongation and electrical conductivity do not reach the lower limit of the target standard because of the value of 4.4.

  From the above results, it was revealed that Examples 1 to 11 can sufficiently achieve the target standards listed above. Therefore, the copper alloy of the present invention does not contain Be, which is harmful to the environment, has better mechanical properties than the product of Patent Document 1, and suppresses the expensive Ni addition amount and adds Ni and Si. By adjusting the amount, it was found that the mechanical strength represented by the tensile strength and the hardness and the electrical conductivity were high without impairing the physical properties.

Claims (4)

From Cu containing Ni 3.30 to 6.0 wt%, Si 0.8 to 1.7 wt%, Cr 0.5 to 1.5 wt%, Sn 0.1 to 0.3 wt%, and the balance excluding inevitable impurities The Ni / Si weight ratio is 3 to 4, the tensile strength is 820 N / mm ² or more, the hardness is 244 or more in HB (10/3000), and the conductivity is 35% or more in IACS. High strength and high conductivity copper alloy. Ni 3.30 to 6.0 wt%, Si 0.8 to 1.7 wt%, Cr 0.5 to 1.5 wt%, Sn 0.1 to 0.3 wt%, and one kind of Mg and Mn, or Both are comprised of 0.01 to 0.1 wt% and the balance is made of Cu excluding inevitable impurities, the Ni / Si weight ratio is 3 to 4, and the tensile strength is 820 N / mm ² or more, hard A high-strength, high-conductivity copper alloy characterized by having an HB (10/3000) of 244 or more and a conductivity of IACS of 35% or more. From Cu containing Ni 3.30 to 6.0 wt%, Si 0.8 to 1.7 wt%, Cr 0.5 to 1.5 wt%, Sn 0.1 to 0.3 wt%, and the balance excluding inevitable impurities At the same time, after the copper alloy having a Ni / Si weight ratio of 3 to 4 is subjected to a solution treatment at a solution treatment temperature of 850 ° C. to 950 ° C., the cold work rate is relative to the cross-sectional area of the original material. It is cold-worked to 10 to 40%, and then subjected to aging treatment at a treatment temperature of 400 to 500 ° C., and has a tensile strength of 820 N / mm ² or more and a hardness of 244 in HB (10/3000). As described above, the method for producing a high-strength, high-conductivity copper alloy characterized in that the conductivity is 35% or more by IACS. Ni 3.30 to 6.0 wt%, Si 0.8 to 1.7 wt%, Cr 0.5 to 1.5 wt%, Sn 0.1 to 0.3 wt%, and one kind of Mg and Mn, or A copper alloy containing 0.01 to 0.1 wt% of both and the balance being made of Cu excluding inevitable impurities and having a Ni / Si weight ratio of 3 to 4, is subjected to a solution treatment temperature of 850 ° C. to 950 ° C. After solution treatment in the range of ° C., cold work is performed so that the cold work rate is 10 to 40% with respect to the cross-sectional area of the original material, and then aging treatment is performed at a treatment temperature of 400 to 500 ° C. Manufactured and manufactured a high-strength, high-conductivity copper alloy characterized by a tensile strength of 820 N / mm ² or more, a hardness of 244 or more in HB (10/3000), and a conductivity of 35% or more in IACS Method.