Cu-mn-co-p-based alloy and manufacturing method therefor

Abstract

The present invention provides a Cu-Mn-Co-P-based alloy, comprising 0.10-0.60 wt% of Mn, 0.15-0.50 wt% of Co, and 0.04-0.39 wt% of P, with the balance being composed of Cu and unavoidable impurities. The Cu-Mn-Co-P-based alloy has a composition ratio relationship satisfying the following formulas (1) and (2): 0.25≤{Mn} / {Co}≤4.0 (1); and 2.8≤({Mn}+{Co}) / {P}≤5.0 (2), wherein {Mn}, {Co}, and {P} respectively represent the mass percentages (wt%) of Mn, Co, and P in the Cu-Mn-Co-P-based alloy; and the electrical conductivity (EC) and tensile strength (TS) of the Cu-Mn-Co-P-based alloy satisfy the following formula: {EC}×{TS}≥450 (3), wherein {EC} represents the electrical conductivity of the Cu-Mn-Co-P-based alloy with % IACS as the unit, and {TS} represents the tensile strength of the Cu-Mn-Co-P-based alloy with MPa as the unit. In addition, as a plate / strip material, the good bending workability with the ratio R / t of a minimum bending radius to a plate thickness being less than 2.0 is exhibited. The Cu-Mn-Co-P-based alloy can be produced by using conventional copper alloy casting, processing, and heat treatment devices, can be manufactured by means of a special heat treatment process combining high-temperature short-time heat treatment and low-temperature long-time heat treatment, and can be used in fields requiring wide characteristics of the electrical conductivity of 60-90% IACS and the corresponding tensile strength of 800-500 MPa.

Description

Cu-Mn-Co-P alloy and method for producing the same TECHNICAL FIELD

[0001] The present invention relates to a Cu-Mn-Co-P alloy and a method for producing the same, which are used in various couplings, integrated circuit lead frames, contact wires for high-speed railways, electric automobile and electric switches, radiators, relays, switches, and the like, and which are required to have high electrical conductivity and heat transfer properties. The Cu-Mn-Co-P alloy has excellent electrical conductivity and heat transfer properties, and also has good strength and bending workability. BACKGROUND

[0002] In various electric and electronic parts, a base copper material is used, and in order to suppress heat generated at the time of current conduction, the material is required to have good electrical conductivity and heat transfer properties (heat dissipation properties). In addition, in order to ensure current flow, sufficient contact pressure is required between parts, and thus the copper alloy material is required to have sufficiently high strength. Furthermore, electronic parts are generally formed by bending, and thus the material is required to have good bending workability.

[0003] Currently, high-conductivity and high-strength copper alloy materials are widely used, and different copper alloy systems are required according to the use. There are two main characteristic regions. One is a Cu-Cr-(Zr) system alloy (for example, C18140, C18150, C18400, C18080, and the like) having an electrical conductivity of 75 to 85% IACS and a tensile strength of 580 to 500 MPa, and the other is a Cu-Ni-P system alloy (for example, C19000 and KLF170 of Kobe Steel, Ltd., and the like) and a Cu-Co-Si system alloy (NKC4419 of Nippon Kinzoku Co., Ltd., and the like) having an electrical conductivity of about 60 to 65% IACS and a tensile strength of 650 to 600 MPa. However, there is no commercialized copper alloy in the intermediate region of the above two regions, that is, an electrical conductivity of about 70% IACS (between 65 and 75% IACS).

[0004] In recent years, with the high-speed transmission (large current) and miniaturization of electrical and electronic components, and the popularity of electric vehicles and the increase in high-speed rail, the strength and electrical conductivity of copper alloy materials used are required to be higher and higher. Since the strength and electrical conductivity are known to be inversely related to each other, quantitative evaluation of high-strength high-conductivity copper alloys requires comparing the tensile strength at a specific electrical conductivity, or comparing the electrical conductivity at a specific tensile strength. There is a simple comparison method for determining this, which is to multiply the product of the electrical conductivity (EC) and the tensile strength (TS) as a high-strength high-conductivity factor σ, i.e., σ = EC x TS. The unit of tensile strength is MPa and the unit of electrical conductivity is % IACS, and the σ of commercial copper alloys on the international market (excluding some special high-quality alloys that do not take into account bending workability, heat resistance, etc.) is generally not more than 450. For example, the tensile strength corresponding to an electrical conductivity of 60 and 85 % IACS is not more than 750 and 530 MPa, respectively.

[0005] In view of the actual market demand and the fact that existing copper alloys cannot meet the requirements of having a high-strength high-conductivity factor σ exceeding 450, while also having good bending workability, the present invention was developed and completed. SUMMARY

[0006] The inventors of the present invention have conducted detailed investigations on Cu-Mn-P alloys, Cu-Co-P alloys, and Cu-Mn-Co-P alloys, which are mixtures of the two types of alloys, based on different alloys from existing Cu-Cr, Cu-Ni-P, and Cu-Co-Si systems. It was found that Cu-Mn-P alloys have the same precipitation strengthening effect as Cu-Ni-P, and that the precipitates thereof are needle-shaped structures that are not prone to coarsening (overaging and low heat resistance) during aging and heat treatment. However, the electrical conductivity of Cu-Mn-P alloys is only 40-50 % IACS, which is lower than the 60-65 % IACS of Cu-Ni-P alloys, and therefore Cu-Mn-P alloys have not been practically developed so far.

[0007] Cu-Co-P alloys have the same electrical conductivity (80-85 % IACS) as Cu-Cr (-Zr) alloys, and are relatively easy to manufacture (low element oxidation during solution casting and low solid solution temperature, etc.), and some commercial development has been achieved, such as the DK-10 alloy of DOWA Co., Ltd. in Japan and the HRSC alloy of Mitsubishi Copper Co., Ltd. However, Cu-Co-P alloys have slightly lower strength (30 MPa lower tensile strength or about HV10 lower hardness) compared to Cu-Cr (-Zr) alloys, and have not been further commercialized.

[0008] The inventors of the present invention based on the characteristics of Cu-Mn-P alloy and Cu-Co-P alloy, developed the Cu-Mn-Co-P alloy. It is found that in the specific component range and mutual ratio relationship of Mn, Co, P, and specific manufacturing process conditions, the Mn-P and Co-P precipitates can form a special structure, achieve the superimposed strengthening effect of the two precipitates, and achieve the Cu-Mn-Co-P alloy with excellent comprehensive properties of electrical conductivity, strength, heat resistance, and bending processability. The present invention is completed based on these findings.

[0009] Specific description:

[0010] One of the purposes of the present invention is to solve the deficiencies of the prior art and provide a Cu-Mn-Co-P alloy with excellent comprehensive properties of electrical conductivity, strength, heat resistance, and bending processability.

[0011] The second purpose of the present invention is to provide a specific manufacturing process condition of the aforementioned Cu-Mn-Co-P alloy, which can finally achieve the Mn-P and Co-P precipitates to form a special structure and achieve the superimposed strengthening effect of the two precipitates.

[0012] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0013] The present invention provides a Cu-Mn-Co-P alloy containing 0.10-0.60wt% of Mn, 0.15-0.50wt% of Co, 0.04-0.39wt% of P, and the rest being Cu and unavoidable impurities, which has a component ratio relationship satisfying the following formula (1) and (2):

[0014] 0.25≤{Mn} / {Co}≤4.0……(1); 2.8≤({Mn}+{Co}) / {P}≤5.0……(2);

[0015] Wherein {Mn}, {Co} and {P} represent the weight percentage wt% of Mn, Co and P in the Cu-Mn-Co-P alloy, respectively.

[0016] Preferably, the Cu-Mn-Co-P alloy contains 0.15-0.40wt% of Mn, 0.15-0.35wt% of Co, 0.06-0.23wt% of P, and the rest being Cu and unavoidable impurities, which has a component ratio relationship satisfying the following formula (1) and (2):

[0017] Preferably, it further contains one or more selected from the group consisting of Ni, Fe, Mg, Cr, Sn, Zn, Zr, Ag, Ti and lanthanide rare earth elements, and the total amount of which is 0.2 wt% or less.

[0018] More preferably, it further contains one to three selected from the group consisting of Ni, Fe, Mg, Cr, Sn, Zn, Zr, Ag, Ti and lanthanide rare earth elements, and the total amount of which is 0.075-0.15 wt%.

[0019] The electrical conductivity (EC) and tensile strength (TS) of the Cu-Mn-Co-P alloy described above satisfy the following formula (3); {EC} x {TS} ≧ 450 … (3)

[0020] wherein {EC} represents the electrical conductivity of the Cu-Mn-Co-P alloy in %IACS unit, and {TS} represents the tensile strength of the Cu-Mn-Co-P alloy in MPa unit.

[0021] Preferably, the Cu-Mn-Co-P alloy has a good bending workability with a minimum bending radius to plate thickness ratio R / t of less than 2.0.

[0022] The electrical conductivity is measured according to the method prescribed in JIS-H0505. The tensile strength is measured according to the method prescribed in JIS-Z2241 from a sample cut in the length direction of the material. The bending workability is evaluated by the value of the minimum bending radius R to plate thickness t obtained by bending processing according to the 90° W-type bending processing method prescribed in JIS-H3110 on a sample (10 mm in width) taken in the rolling direction (LD) and the direction perpendicular to the rolling direction (TD) of the plate strip.

[0023] The present application provides a manufacturing method of the Cu-Mn-Co-P alloy, which comprises sequentially performing the following steps on a copper alloy having the composition described above: continuously or semi-continuously cast ingot, hot working such as hot rolling (hot forging, hot extrusion), cold working such as cold rolling (cold forging, cold drawing), heat treatment such as solid solution and aging, and conventional manufacturing processes such as face milling and pickling. In the above manufacturing process, the specific processing and heat treatment processes adopt the special process conditions of the present application.

[0024] Specifically, it comprises the following steps performed sequentially:

[0025] S1: continuously or semi-continuously cast ingot, hot working by hot rolling, hot forging or hot extrusion;

[0026] S2: cold working by cold rolling, cold forging or cold drawing;

[0027] S3: intermediate heat treatment at 600-700°C for 30 seconds to 3 minutes;

[0028] S4: aging treatment at 350-450°C for 3-10 hours;

[0029] S5: cold rolling and low temperature annealing after final cold rolling.

[0030] Preferably, the temperature of the hot working in S1 is 950-1000°C.

[0031] Preferably, the intermediate heat treatment in S3 is at 650-720°C for 1 to 1.5 minutes; the aging treatment in S3 is at 380-420°C for 3-6 hours.

[0032] Preferably, the reduction ratio of the final cold rolling is 20-60%.

[0033] The Cu-Mn-Co-P alloy according to the present application has excellent comprehensive properties which are difficult to obtain with the current alloy composition and manufacturing technology. It is produced to meet the needs of high current, miniaturization and densification of electronic components which are expected in the future. BRIEF DESCRIPTION OF DRAWINGS

[0034] Fig. 1 a: Comparative Example No. 15 (84% IACS, HV 146) with high Co content, spherical precipitates;

[0035] Fig. 1 b: Comparative Example No. 16 (56.2% IACS, HV 173) with high Mn content, needle-like precipitates;

[0036] Fig. 1 c: Comparative Example No. 22 (64.1% IACS, HV 168) with conventional process (without intermediate heat treatment), needle-like and spherical precipitates mixed;

[0037] Fig. 1 d: Invention Example No. 2 (72.4% IACS, HV 192), special shaped precipitates with needle-like contained in spherical.

[0038] DETAILED DESCRIPTION

[0039] I. Alloy Composition

[0040] Mn (manganese) and Co (cobalt) can form compounds with P (phosphorus) to achieve precipitation strengthening for improving the strength of the copper alloy. When the content of Mn is less than 0.1 wt%, the precipitation strengthening effect is insufficient; when the content of Mn exceeds 0.6 wt%, the electrical conductivity is excessively low, and the final electrical conductivity of the material is difficult to exceed 60% IACS. When the content of Co is less than 0.15 wt%, the precipitation strengthening effect is insufficient; when the content of Co exceeds 0.5 wt%, the solid solution temperature required is excessively high, which is difficult for industrial production, and Co is a relatively expensive element, which is not conducive to the cost of the material. Therefore, the content of Mn is between 0.1 wt% and 0.6 wt%, and the content of Co is between 0.15 wt% and 0.5 wt%. Preferably, the content of Mn is between 0.15 wt% and 0.4 wt%, and the content of Co is between 0.15 wt% and 0.35 wt%.

[0041] The purpose of the present application is to fully utilize the superimposed effect of Mn-P and Co-P compound precipitation strengthening, therefore the contents of Mn and Co should not differ too much, and should satisfy the following formula (1): 0.25 ≤ {Mn} / {Co} ≤ 4.0 …… (1);

[0042] In other words, the ratio of {Mn} or {Co} to {Mn+Co} is more than 20% but less than 80%. If the ratio of {Mn} / {Co} is less than 0.25 or greater than 4.0, the contents of Mn and Co differ too much, and the obtained alloy characteristics are close to Cu-Mn-P alloy or Cu-Co-P alloy, which does not achieve the purpose of the present application. More preferably, the ratio of {Mn} / {Co} is greater than 0.5 and less than 2.0.

[0043] P (phosphorus) can form precipitates with Mn and Co to achieve precipitation strengthening. There are many types of precipitates, which vary with the ratio of P to Mn and Co. The investigation results of the present application show that when the ratio of the contents of Mn, Co and P satisfies the following formula (2), the balance between the electrical conductivity and the strength is optimal: 2.8 ≤ ({Mn} + {Co}) / {P} ≤ 5.0 …… (2)

[0044] This ratio reflects the balance of the contents of Mn and Co in the compounds with P, and less than 2.8 or greater than 5.0 indicates excess or deficiency of P content, which will result in low electrical conductivity and strength. Preferably, the ratio of ({Mn} + {Co}) / {P} is between 3.0 and 4.5. According to the content ranges of Mn and Co and formula (2), the content of P is between 0.04 wt% and 0.39 wt%. In addition, when the content of P is too large (for example, more than 0.3 wt%), hot cracking problems are prone to occur, therefore, from the perspective of manufacturability, the upper limit of the ratio in formula (2), i.e. the lower value of the content of P, should be selected as much as possible within the range satisfying formula (2). Preferably, the content of P is between 0.06 wt% and 0.23 wt%.

[0045] For other elements, one or more elements selected from Ni, Fe, Mg, Cr, Sn, Zn, Zr, Ag, Ti and lanthanide rare earth elements can be further contained as necessary depending on the specific situation. For example, Cr, Fe, Mg, Zr, Ti and lanthanide rare earth elements have the effects of refining grains and improving heat resistance; Sn and Ni have solid solution strengthening effects; Zn has the effect of preventing the peeling of a surface plating layer, and Ag has the effect of improving electrical conductivity, etc. When one or more of these elements is added, the above-mentioned various effects are sufficiently exerted, and the total content thereof is preferably 0.01 wt% or more. However, if the content of the above-mentioned various elements is too much, the electrical conductivity is easily reduced and the balance between Mn-Co-P is easily broken, resulting in a decrease in characteristics. Therefore, the total content of these elements is preferably controlled to be 0.15 wt% or less, more preferably 0.1 wt% or less, such as 0.075%.

[0046] II. Characteristics

[0047] 1. Electrical conductivity (and thermal conductivity) and strength:

[0048] At present, the most commonly used high-conductivity and high-strength copper alloy sheet and strip for high-speed railway contact wire, smart phone, computer and other components (power terminal, USB, charger, etc.) can be divided into two categories. One is Cu-Cr (-Zr) alloy and Cu-Co-P alloy with electrical conductivity of about 80% IACS (75-85% IACS) and tensile strength of 570-500 MPa; the other is Cu-Ni-P alloy and Cu-Co-Si alloy with electrical conductivity of 60-65% IACS and tensile strength of 650-600 MPa. The high-strength high-conductivity factor σ is difficult to break through 450.

[0049] With the miniaturization of electrical and electronic components, the strength requirement of copper alloy materials is increasing, and the strength of the first type of copper alloy cannot meet the requirements. On the other hand, with the development of high-speed transmission and rapid charging, the electrical conductivity and strength of the second type of copper alloy cannot meet the requirements. Between the two types, there is still a blank in the market for copper alloy materials with good characteristic balance, electrical conductivity of about 70% IACS, and tensile strength of σ≧450 (i.e. electrical conductivity≧70% IACS, tensile strength≧650 MPa). The market demand is getting higher and higher.

[0050] The temperature rise problem caused by high current high-speed transmission is also becoming more and more serious, and copper alloy materials are required to have better heat dissipation (thermal conductivity). Since the thermal conductivity coefficient is in direct proportion to the electrical conductivity, the heat dissipation and electrical conductivity are generally unified, that is, the electrical conductivity is uniformly represented.

[0051] Bending workability: For high conductive copper alloy applications, generally, the bending workability is required to be relatively low. If the directions parallel and perpendicular to the rolling direction on the plate surface are referred to as LD and TD directions, respectively, the bending workability in the LD and TD directions is required to satisfy the ratio R / t of the minimum bending radius R at which no cracks occur in 90° W-type bending work to the plate thickness t, and generally, the ratio R / t is required to be 2.0 or less. The bending workability in the LD direction as described herein means that a test piece is cut so that the length direction of the test piece is parallel to the rolling direction, and the bending axis at the time of bending work is the TD direction. Similarly, the bending workability in the TD direction means that a test piece is cut so that the length direction of the test piece is perpendicular to the rolling direction, and the bending axis at the time of bending work is the LD direction.

[0052] III. Manufacturing method

[0053] The copper alloy material of the present application as described above can be a plate strip, a bar wire, a tubular, and a special-shaped material, and can be manufactured, for example, by the following general process flow. That is, melting / casting - heating and working (hot rolling, hot forging, hot extrusion, etc.) - cold working (cold rolling, cold forging, drawing, etc.) - heat treatment (solution, aging, recrystallization annealing, etc.) - final finishing - low-temperature stress relief annealing, etc.

[0054] However, as will be described below, the control of several process conditions therein is very important. In addition, although not mentioned above, according to the actual needs, optional facing after hot rolling, optional pickling, grinding or degreasing after heat treatment, draw bending straightening, etc. can be performed. The processes are further described below with respect to the plate strip material which has the most complicated manufacturing process.

[0055] 1. [Melting / casting]

[0056] Either the continuous or semi-continuous casting method of the general copper alloy can be used. In order to prevent the oxidation of P, P is added after the complete dissolution of Cu and other alloying elements before the start of casting, or charcoal is added in the melting furnace and the flow channel, nitrogen gas protection is performed, etc.

[0057] 2. [Heating and working]

[0058] The heating temperature of the general copper alloy is between 900 and 950°C, and the copper alloy of the present application has a relatively high solution temperature of the coarse Mn-P and Co-P compounds solidified between the dendrites in the cast structure, and thus, the heating temperature is appropriately higher than that of the general copper alloy (between 950 and 1000°C). If the heating temperature is not high enough, the Mn-P and Co-P compounds cannot be completely dissolved (there are residues), and the fine precipitates are small in the final aging, resulting in low strength.

[0059] The ingot is heated at 950-1000°C for 3-5 hours and then hot worked (hot rolling, hot forging, hot extrusion, etc.). The hot working process can be performed according to the process for general copper alloys. After hot working, the material is preferably water cooled as much as possible to prevent the precipitation of Mn-P and Co-P compounds.

[0060] 3. Cold working

[0061] Next, cold working is performed to the desired size according to the final product size and the final working rate.

[0062] 4. Solution treatment

[0063] In order to re-dissolve the small amount of Mn-P and Co-P compounds precipitated during hot working, solution treatment is performed. The appropriate solution treatment temperature varies depending on the alloy composition. In the range of the alloy composition of the present application, the appropriate solution treatment temperature is 800-1000°C, and the treatment time can be several seconds to several minutes. The appropriate solution treatment time varies depending on the treatment temperature and the material size, and can be determined by experiment. Specifically, it can be determined by observing the microstructure after solution treatment. A precise method is to observe the presence or absence of precipitates by transmission electron microscopy, and a simple metallographic observation method can also be used, with a recrystallized grain diameter of about 10 μm as a condition for substantially dissolving the precipitates.

[0064] If the hot working temperature is relatively high and the cooling rate after hot working is fast, the precipitates are small, and the solution treatment at this time can be omitted. Or when the electrical conductivity requirement for the final product is relatively high and the strength requirement is relatively low, the solution treatment at this time can also be omitted.

[0065] 5. Cooling control after solution treatment

[0066] After conventional solution treatment, in order to prevent precipitation and coarsening of precipitates during cooling, the solution is quenched (or water cooled), i.e., so-called quenching. Next, according to the general process flow, aging treatment (or cold working-aging treatment) is performed. In general, for precipitation-type copper alloys, there is an optimal precipitation temperature Tm (also the aging temperature) range. When aging above the Tm temperature, the nucleation of precipitates is small and the precipitates grow fast due to the high temperature, resulting in large size and small density of the precipitates, and small precipitation strengthening effect. When aging below the Tm temperature, the nucleation and growth of the precipitates are both slow, and the precipitation strengthening effect is also small, or it is necessary to have a very long aging time and cannot be produced on a large scale.

[0067] Cu-Mn-Co-P system alloy has two kinds of precipitates, Mn-P and Co-P, corresponding to different precipitation temperature ranges. The precipitation temperature range of Co-P precipitate is about 500-800℃, and the precipitation temperature range of Mn-P precipitate is 300-500℃. If the Cu-Mn-Co-P system alloy is aged at a relatively high temperature (such as 550℃) for Co-P precipitation, the temperature is too high relative to the Mn-P precipitate, the Mn-P precipitate has small density and grows rapidly, and the precipitation strengthening effect becomes very small; if aging at a relatively low temperature (such as 400℃), the temperature is too low relative to the Co-P precipitate, and thus the precipitation amount is small, and the precipitation strengthening effect becomes very small.

[0068] After the solid solution treatment, the present application adopts slow cooling treatment instead of the conventional rapid cooling treatment. The purpose is to let the material at high temperature (such as 900-950℃) after the solid solution treatment stay for several seconds to tens of seconds between cooling to about 600℃, intentionally let the Co-P compound partially precipitate, and not be coarse due to the very short time. At the same time, a small amount of Mn-P compound precipitates in this temperature range will promote the refinement of Co-P precipitates. The cooling control after the solid solution treatment can be realized by adjusting the cooling conditions (air pressure and air flow, etc.) of the cooling zone and the through-plate speed, etc. of the conventional continuous annealing furnace (air cushion furnace and vertical furnace with multiple heating-cooling zones, etc.). The specific residence time can be determined by the TTT curve obtained by prior laboratory experiments for different compositions.

[0069] If the residence time is too short between the solid solution temperature and 600℃, the Co-P compound precipitates too little to achieve the precipitation strengthening effect of the present application, and if the residence time is too long, it is easy to cause the rapid growth of Co-P precipitates, and also cannot achieve the effect of the present application. In the composition range of the present application, 10-60 seconds can achieve the effect. If the production equipment does not have the ability to monitor the temperature and adjust the cooling conditions, it can also be realized by the method of intermediate heat treatment (i.e. after the conventional solid solution-rapid cooling treatment, then solid solution-rapid cooling treatment at 600-700℃). Only the process and manufacturing cost are increased.

[0070] 6, [aging treatment]

[0071] Next, aging treatment is carried out. The aging treatment temperature is preferably between 350-500℃, and the aging treatment time is in the range of about 3-10 hours to obtain good results. The purpose of aging is to make the Mn-P compound precipitate as much as possible and the Co-P compound further precipitate. Through the superposition of the precipitation effects of the two kinds of precipitates, the strength and conductivity of the material are improved. Similarly, if the aging temperature is too low and the aging time is too short, the precipitation is insufficient; if the aging temperature is too high and the aging time is too long, it is easy to cause overaging and low strength.

[0072] 7, [final cold working]

[0073] To further increase the strength of the material, after the aging treatment, a final cold working with a reduction of 20-60% can be performed. As the reduction increases, the strength increases, while the heat resistance and bending workability decrease. The inventors have found, through detailed investigations, that if the reduction is controlled to be between 20-60%, the strength, heat resistance and bending workability targets of the present invention can be achieved.

[0074] 8. [Low temperature annealing]

[0075] If the final cold working is performed, to reduce and eliminate the residual stress in the material and to increase the heat resistance, a low temperature annealing is performed after the working. At the same time, the low temperature annealing can also increase the electrical conductivity. The heating temperature in the low temperature annealing can be set to be within 350-550°C, continuous annealing for several seconds to several minutes, or 150-350°C, batch furnace annealing for several hours. Accordingly, if the temperature is set too high, the softening of the sheet can easily occur. On the contrary, if the temperature is set too low, the desired effect cannot be achieved. IV. Examples

[0076] Square ingots with the compositions shown in Table 1 were cast using a vertical semi-continuous casting machine. After cutting the head and tail of the ingot, the ingot was heated to 960°C and held for 3 hours, and then hot-rolled. After the hot-rolling, the ingot was water-cooled, and the surface oxide film was removed by milling. Then, the ingot was cold-rolled to the desired thickness, and then solution-treated at 800-1000°C. For the alloys with different compositions, the metallographic observation at different solution treatment temperatures and times was observed in advance in a laboratory experiment, and the temperature and time corresponding to the average grain diameter of 8-15 μm after the solution treatment were used as the temperature of the heating and soaking zones of the continuous annealing furnace, and the time obtained by the ratio of the furnace length of the heating and soaking zones to the sheet passing speed.

[0077] 600-700°C x 1 min intermediate heat treatment, 400°C aging treatment, and the hardness was maximized at 400°C by adjusting the aging time. The optimum aging treatment time for the alloy composition was known in advance from the experiment. The material after the aging treatment was final cold-rolled at a reduction of 50%, and then low temperature annealed for 1 minute in a heating furnace at 400°C. The necessary pickling, degreasing, stretch bending, trimming, etc. were performed in between. Finally, the precipitates of the obtained sheet were observed and the properties were evaluated. The thickness of the test sheet was uniform at 0.20 mm. The main manufacturing conditions of each test sheet are shown in Table 2.

[0078] [Table 1] Chemical composition of the alloy

[0079] Note: The underlined indicates that it is out of the range of the present invention

[0080] The following evaluations were made on the properties of the obtained test pieces. Namely: electrical conductivity, tensile strength, heat resistance temperature, and bending processability.

[0081] [Electrical conductivity]: Measured according to the method prescribed in JIS-H0505.

[0082] [Tensile strength]: Measured according to the method prescribed in JIS-Z2241.

[0083] [Bending processability]: Plate-shaped test pieces (each having a width of 10 mm) cut in the length direction respectively as LD and TD were subjected to bending process according to the 90° W-type bending process method prescribed in JIS H3110. The surface and cross section of the test pieces after bending process were observed under 100 times using an optical microscope. The smallest bending radius R at which no cracks occurred was obtained. The value of the ratio R / t of the smallest bending radius R to the plate thickness t was used as an evaluation of the bending processability. The smaller the value of R / t, the better the bending processability.

[0084] [Observation of precipitates]: In order to reduce the influence of dislocations on the observation of precipitates, observation of precipitates was performed on the test pieces after aging treatment under TEM observation conditions.

[0085] The results of the property evaluations are shown in Table 2.

[0086] [Table 2]: Results of property evaluations

[0087] Note: The underlines indicate that the values are outside the prescribed range of the present application.

[0088] As can be seen from Table 2, all of the inventive examples have a good balance between electrical conductivity and tensile strength, i.e. high-strength high-conductivity factor (electrical conductivity x tensile strength) of more than 450, and good bending processability with R / t in both the LD and TD directions of less than 2.0, under the component requirements and manufacturing process conditions of the present application.

[0089] In comparison, Comparative Examples 11-14 are examples in which the Mn, Co and P contents or ratios are outside the ranges specified in the present application and do not provide good properties. Example 11 has too low a content of Mn, Co and P, and as a result, the amount of precipitates formed is too small, and the strength is low. Comparative Example 12 has too high a content of Mn, Co and P, and in particular, the P content exceeds 0.40 wt%, resulting in hot rolling cracking, and the subsequent process cannot be performed and the properties cannot be evaluated. Examples 13 and 14 have a (Mn+Co) / P ratio that is too large and too small, i.e., one of (Mn+Co) or P is relatively excessive, resulting in a small amount of precipitates, and the strength and electrical conductivity are relatively low. Examples 15 and 16 have a Mn / Co ratio that is too large and too small, resulting in low strength or low electrical conductivity. Example 15 has too low a content of Mn, resulting in a result similar to that of a conventional Cu-Co-P alloy, i.e., high electrical conductivity but low strength. In contrast, Example 16 has too low a content of Co, resulting in a result similar to that of a conventional Cu-Mn-P alloy, i.e., a tensile strength of 747 MPa, which is relatively high, but an electrical conductivity of only 55.1% IACS. Example 17 is an example in which the content of other elements is too large, resulting in poor properties. Since Ni also forms a compound precipitate with P, the excessive addition of Ni disrupts the balance between Mn-Co-P, resulting in lower electrical conductivity and tensile strength than in the inventive examples.

[0090] Comparative Examples 21-23 are examples in which the alloy compositions are those of Inventive Examples 1-3, but the manufacturing process conditions are outside the ranges specified in the present application, and good properties are not obtained. Examples 21-23 do not have intermediate heat treatment, and when the aging temperature and aging time are adjusted to the optimum aging conditions according to the conventional process flow, the results are that the strength and electrical conductivity are much lower than in Inventive Examples 1-3, which have the same manufacturing conditions except for the intermediate heat treatment. Examples 24 and 25 are examples in which the alloy composition is that of Inventive Example 2, but the intermediate heat treatment conditions are not suitable, resulting in properties that do not achieve the effects of the present application. Example 24 has an intermediate heat treatment temperature that is too low and a time that is too short, resulting in too small an amount of Co-P precipitates. The final electrical conductivity and tensile strength are slightly improved compared to Comparative Example 22, which does not have intermediate heat treatment, but are still much lower than in Inventive Example 2. Example 25 is an example in which the intermediate heat treatment time is too long or the temperature is too high, resulting in coarse Co-P precipitates and low strength.

[0091] [Observation of Precipitates]: Several alloy compositions were selected in which the total amount of alloying elements (Mn, Co) and the P content were similar, and the precipitates after aging were observed in order to reduce the influence of dislocations. As shown in the TEM photographs in Figures 1 a-d.

[0092] [According to Rule 26 Corrected 10.09.2025] The precipitate morphology of Comparative Example No. 15 and No. 16 is close to the Cu-Co-P and Cu-Mn-P precipitates reported in various literatures, which are spherical and acicular respectively, and the results of high conductivity and low strength or vice versa are also consistent. Comparative Example 22 is the alloy composition of the present invention, Example No. 2, a Cu-Mn-Co-P alloy with equal proportion of Mn and Co, using the conventional solution-quenching without intermediate heat treatment process, the result is a mixture of acicular and spherical precipitates, without the effect of superimposed strengthening of the two precipitates, the conductivity and strength obtained are only in the middle of Comparative Example No. 15 and No. 16. While the relationship between the two precipitates cannot be clearly determined at present, the result is that the acicular precipitates are refined and the amount of precipitates is significantly increased, and the conductivity and strength are improved at the same time.

Claims

1. A Cu-Mn-Co-P-based alloy, characterized by, A Cu-Mn-Co-P alloy containing 0.10-0.60 wt% of Mn, 0.15-0.50 wt% of Co, 0.04-0.39 wt% of P, the balance of Cu and unavoidable impurities, has a composition ratio relationship satisfying the following formulae (1) and (2) 0.25 ≤ {Mn} / {Co} ≤ 4.0 (1); 2.8 ≤ ({Mn}+{Co}) / {P} ≤ 5.0 (2); wherein {Mn}, {Co} and {P} represent the mass percentages of Mn, Co and P in the Cu-Mn-Co-P alloy, respectively. A Cu-Mn-Co-P alloy containing 0.10-0.60 wt% of Mn, 0.15-0.50 wt% of Co, 0.04-0.39 wt% of P, the balance of Cu and unavoidable impurities, has a composition ratio relationship satisfying the following formulae (1) and (2) 0.25 ≤ {Mn} / {Co} ≤ 4.0 (1); 2.8 ≤ ({Mn}+{Co}) / {P} ≤ 5.0 (2); wherein {Mn}, {Co} and {P} represent the mass percentages of Mn, Co and P in the Cu-Mn-Co-P alloy, respectively.

2. The Cu-Mn-Co-P alloy according to claim 1, wherein A Cu-Mn-Co-P alloy containing 0.15-0.40 wt% of Mn, 0.15-0.35 wt% of Co, 0.06-0.23 wt% of P, the balance of Cu and unavoidable impurities, has a composition ratio relationship satisfying the following formulae (1) and (2) 0.5 ≤ {Mn} / {Co} ≤ 2.0 (1); 3.0 < ({Mn}+{Co}) / {P} < 4.5 (2).

3. The Cu-Mn-Co-P-based alloy according to claim 1 or 2, characterized by, Further containing one or more selected from the group consisting of Ni, Fe, Mg, Cr, Sn, Zn, Zr, Ag, Ti and lanthanide rare earth elements, and the total amount is 0.2 wt% or less.

4. The Cu-Mn-Co-P-based alloy according to claim 1 or 2, characterized by, Further containing one to three selected from the group consisting of Ni, Fe, Mg, Cr, Sn, Zn, Zr, Ag, Ti and lanthanide rare earth elements, and the total amount is 0.075-0.15 wt%.

5. The Cu-Mn-Co-P-based alloy according to claim 1 or 2, characterized by, The electrical conductivity and tensile strength satisfy the following formula (3): {EC} x {TS} ≧ 450 (3); wherein {EC} represents the electrical conductivity of the Cu-Mn-Co-P alloy in units of %IACS, and {TS} represents the tensile strength of the Cu-Mn-Co-P alloy in units of MPa. The Cu-Mn-Co-P alloy processed plate has good bending workability with a minimum bending radius to plate thickness ratio R / t of less than 2.

0.

6. The Cu-Mn-Co-P-based alloy according to claim 1 or 2, characterized by, It comprises the following steps in sequence:

7. The method of producing the Cu-Mn-Co-P system alloy according to any one of claims 1 to 6, characterized by, S1: continuously or semi-continuously cast ingot is hot worked by hot rolling, hot forging or hot extrusion; S2: cold working is performed by cold rolling, cold forging or cold drawing; S3: intermediate heat treatment is performed at between 600-700℃ for between 30 seconds to 3 minutes; S4: aging treatment is performed at a temperature interval of 350-450℃ for 3-10 hours; S5: low temperature annealing is performed after cold rolling and final cold rolling. The temperature of the hot working in S1 is 950-1000℃.

8. The Cu-Mn-Co-P alloy production method according to claim 7, wherein The intermediate heat treatment in S3 is performed at between 650-720℃ for between 1 to 1.5 minutes; the aging treatment in S3 is performed at a temperature interval of 380-420℃ for 3-6 hours.

9. The Cu-Mn-Co-P alloy production method according to claim 7, wherein The processing rate of the cold rolling is 20-60%.

10. The Cu-Mn-Co-P alloy production method according to claim 7, wherein ​

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