JP4349631B2 - Manufacturing method of Corson alloy fine wire for electric and electronic equipment parts - Google Patents

Description

  The present invention relates to Cu-Ni-Si-based corson for electronic device parts, which is more demanding in strength, ductility, and conductivity than ever before, as demand for electric devices and electronic devices in recent years is increasing. The present invention relates to a method for producing a fine alloy wire.

  Conventionally, Cu—Ni—Si-based Corson alloys have been used in electrical equipment and electronic parts such as lead frames, terminals, connectors, etc., but are mostly manufactured and sold in the form of strips. By the way, with recent demands and the direction of technological development, with the need for lighter and shorter electric machines and electronic devices, parts used are also becoming smaller. Thus, the copper alloy used in the alloy is required to have high ductility and high electrical conductivity required for high strength and high workability. The Corson alloy is subjected to a precipitation treatment after a solution treatment. That is, the Ni—Si compound is precipitated by the precipitation treatment to improve the strength, ductility and conductivity. In addition, the movement to use this technology in the form of fine lines has become active along with the miniaturization of electronic devices.

Related arts related to this are as follows.
The first prior art aims to provide a plurality of stranded wires having high ductility in addition to high strength and electrical conductivity relating to a piezoelectric connecting wire conductor as disclosed in JP-A-6-60772.
Therefore, as a means for solving this problem, a conductor cross-sectional area of a plurality of strands in which 1.5 to 4.5% Ni, 0.3 to 1.0% Si balance is made of Cu and unavoidable impurities is set to 0. 03-0.3mm ²
The tensile strength is 45 to 90 kgf / mm ² , the elongation at break is 8 to 20%, and the conductivity is 50% IACS or more.

The second prior art is as disclosed in Japanese Patent Application Laid-Open No. 2002-356728, which is a copper and copper alloy strip and a method for producing the same, and obtaining a copper or copper alloy strip excellent in balance between strength and workability. It is intended for the purpose. Thus, the solution means that when the degree of work η in the final cold rolling is expressed by the following formula, a fine crystal grain having a grain size of 1 μm or less is obtained after the final cold rolling by performing a rolling process of η ≧ 3. The copper and copper alloy strips were characterized by having a tensile test and an elongation of 2% or more.
Note: processing formula; η = ln (T0 / T1), T0: thickness before rolling, T1: thickness after rolling

Japanese Patent Application Laid-Open No. 6-60772; Japanese Patent Application No. 4-221716 JP 2002-356728 A; Japanese Patent Application 2002-40670

However, the technique disclosed in Japanese Patent Application Laid-Open No. 6-60772 is a method for producing a plurality of stranded wires, and is not a method for producing a thin copper alloy wire as an object of the present invention. Moreover, the technique of Unexamined-Japanese-Patent No. 2002-356728 is a method of manufacturing a strip, and is not the method of manufacturing the thin copper alloy wire made into the objective of this invention. The characteristics of each of the above prior arts are as follows. In the technique disclosed in Japanese Patent Laid-Open No. 6-60772, a solution treatment is performed at 950 ° C. to perform drawing with a workability of 99% or more, and then a precipitation treatment is performed at 420 to 500 ° C. for 2 hours or longer. Further, for the purpose of improving the strength, Ag is added to the Corson alloy, and after the precipitation treatment, 96% of the final cold work is performed, and the precipitation treatment is further performed at 450 ° C. There is no description about the crystal grain size.
Japanese Patent Application Laid-Open No. 2002-356728 performs precipitation treatment at a temperature at which strength is increased after solution treatment, and then performs final rolling at a workability of 95%, but the ductility is not sufficient.

  Thus, it is desired that the mechanical properties of the copper alloy for electronic device parts have high strength and good workability, that is, ductility. However, strength and ductility are in a contradictory relationship. When rolling is performed in order to increase the strength due to work hardening, ductility is reduced, and good workability cannot be obtained as it is. Conventionally, the strength and ductility are maintained by controlling the crystal grain size to be small during the precipitation treatment. However, the present situation is that a crystal grain size of 2 to 3 μm or less cannot be obtained.

  However, in this method, if the precipitation temperature is lowered in order to refine the crystal grain size, it takes a long time to heat the precipitation sufficiently and to obtain good strength, ductility and conductivity. Either special heating or special heating was inefficient. On the other hand, when the precipitation treatment is performed at a high temperature, the heating time is shortened, but there is a problem that the precipitated crystal is coarsened and recrystallization proceeds and the strength is lowered. Therefore, in practice, a rolling process with a workability of 10 to 80% after the solution treatment is performed to increase the strength, and then the precipitation process is performed at a temperature at which the conductivity is increased. Since the strength level is lowered as it is, the conventional situation is that the strength is recovered by a certain degree of rolling, and the balance of strength, ductility, and conductivity is satisfied by strain relief annealing. Another method is to perform precipitation treatment at a temperature at which the conductivity increases after solution treatment, and then roll at a workability of 80% or more to restore strength, and then recover ductility by strain relief annealing. What is being made is the conventional situation.

Moreover, as a recent prior art, solution treatment is performed at a high temperature of 950 ° C., wire drawing is performed at a workability of 99% or more, and precipitation treatment is performed at a high temperature of 500 ° C. for 2 hours, Although high ductility and high electrical conductivity can be obtained, but the strength is greatly reduced, a method of obtaining strength by using a plurality of stranded wires has been proposed. In another method, after a solution treatment at a temperature as high as 950 ° C., a precipitation treatment is performed at a temperature at which the strength is increased, and a dynamic recrystallization is performed in a final rolling step with a workability of 95% or more to obtain fine crystals. However, there is a problem that the ductility having an elongation of 6% or more must be recovered by strain relief annealing, and the strength reduction occurring at that time is not described.
The object of the present invention is to solve the above-mentioned conventional problems and to improve the quality of fine wires and to greatly improve the manufacturing method in order to reduce the size of electric and electronic parts.

In order to solve the above-mentioned problems, the present inventors have conducted extensive research, and as a result, in order to achieve a workability of 99% or more, a novel composition of the fine wire alloy is created as in the above-mentioned claim 1, After solution forming in the state of the ingot of this composition, when cold drawing of 99% or more, and further 99.99% or more, Ni and Si are further diffused in the Cu metal and dynamically dissolved. If recrystallization occurs and crystal grains become ultrafine to submicron and high strength is expressed, and after intermediate precipitation treatment is performed, if cold drawing is finally performed at a workability of 99% or more, In the state where the Ni-Si compound is precipitated, dynamic recrystallization occurs, the crystal grains become ultrafine as submicron, and the final precipitation treatment is performed.
The pinning effect of the Ni—Si compound confirmed that no growth of crystal grain size occurred, and the present invention was achieved. Thus, solution treatment is performed at a lower temperature than before, cold working is performed, intermediate precipitation treatment is performed if necessary, and finally cold drawing is performed with a workability of 99% or more, and then 250 to 500 Precipitation treatment at a temperature of ℃ for a shorter time than before makes ultrafine crystal grains with high strength, ductility and high conductivity, and a balanced Cu-Ni-Si-Mn Corson alloy fine wire is produced. It became possible.

Here, in the case of the thin round wire referred to in the present invention, it is a strand having a sectional diameter of 0.2 mm or less, and in the case of a square wire, it is a strand having a sectional diameter of 0.4 mm or less. Further, the degree of processing referred to in the present invention refers to the degree of workability indicated by the following three expressions.
Degree of processing 1 = (Cross sectional area during solution treatment−Cross sectional area during final precipitation process) / Cross sectional area during solution treatment 2 = (Cross sectional area during intermediate precipitation process−Cross sectional area during final precipitation process) / Degree of cross-sectional area processing during intermediate treatment 3 = (Cross-sectional area during solution treatment-Cross-sectional area during intermediate precipitation process) / Cross-sectional area during solution treatment (Degree of processing 1, 2 must be 99% or more) When solution treatment is performed on ingots with a processing degree of 1, 2, and 3, solution treatment can be omitted in the case of a columnar crystal single phase.)

The composition of the Corson alloy used in the present invention is as follows: Ni: 1.0 to 4.0 wt%, Si: 0.2 to 1.4 wt%, Mn: 0.05 to 0.5 wt%, Zn: 1.0 wt% The following is contained, and the balance is made of Cu and inevitable impurities. You may add 0.005 to 2 wt% of one or more of Mg, Sn, Fe, Ti, P, Zr and Ag as subcomponents to the alloy.
The Corson alloy of the present invention is melted in the atmosphere under a charcoal coating in a high-frequency melting furnace, and then cast into a billet of 13 to 40 mmφ by a horizontal continuous casting machine.

  When the macrostructure of the cast ingot is observed, it consists of columnar crystals, equiaxed crystals, and chill crystals. The chill crystals on the surface can be removed mechanically and chemically, but the equiaxed crystals cannot be removed because they are in the center. In the case where all are columnar crystals, that is, in the case of a columnar crystal single phase structure, in particular, when performing cold wire drawing with a workability of 99% or more, Ni and Si of the same degree as the structure subjected to solution treatment are used. As a result of X-ray microanalyzer analysis and conductivity measurement, solid solubility in Cu was obtained. Therefore, in this case, no solution treatment is necessary. However, ingots have not only columnar crystals but also equiaxed crystals. Therefore, even when cold working or cold working is not applied, solution treatment is performed and Ni and Si are sufficient for Cu. Must be dissolved. In this case, the solution treatment temperature is 700 to 950 ° C. If it is performed at 950 ° C. or higher, the strength decreases. It takes a long time at temperatures lower than 700 ° C. The solution treatment can be performed in the atmosphere. After solution treatment, it can be rapidly cooled in water. The scale attached to the surface can be removed chemically.

  After the solution treatment, the degree of workability 1 is 99% or more, preferably 99, 99% cold wire drawing is applied, and then the final precipitation treatment is performed at a temperature of 400 to 500 ° C. for 30 to 150 minutes. , Ductility and conductivity are increased. After the solution treatment, after cold-drawing at a work degree 3 of 99% or more, intermediate precipitation treatment is performed. Then, when the cold drawing of 99% or more of the degree of work 2 is performed and the final precipitation annealing is performed, the strength is further improved. The intermediate precipitation treatment conditions at this time are 400 to 500 ° C. and 30 to 150 minutes. The final precipitation annealing conditions are 250 to 500 ° C. and 5 to 150 minutes. If the temperature exceeds 500 ° C., the conductivity and elongation increase, but the strength decreases greatly. At 400 ° C. or less, the crystal grain growth rate is reduced by the pinning effect of the Ni—Si compound, the crystal grain size is 1 μm or less, and the decrease in strength is small. Cold wire drawing is performed by a plurality of wire drawing machines. During the process, the surface scale may be chemically removed.

  As described above in detail, according to the present invention, it is possible to inexpensively produce a balanced Corson alloy fine wire that has been impossible to manufacture in the past, has high strength, good ductility, excellent electrical conductivity, and balance. The performance of contact materials for electrical and electronic equipment can be greatly improved.

  As the best mode for carrying out the present invention, in the method for producing a Corson alloy fine wire having the composition of claim 1 or 2, the solution treatment is omitted at the ingot stage of the columnar crystal single phase of claim 3. Is the best. The reason is that the process can be shortened, and finally an ultrafine crystal grain size can be obtained, and a fine wire having high strength, ductility and good conductivity can be obtained.

Next, examples will be specifically described while demonstrating the effects of the present invention.
A Cu—Ni—Si—Mn Corson alloy having the composition shown in wt% in Table 1 was melted in the atmosphere under a charcoal coating by a high-frequency melting furnace, and then cast by a continuous casting machine into 34 mmφ and 18 mmφ billets. Ingot 1 has component values of Ni 2.0 wt%, Si 0.40 wt%, Mn 0.14
The component values of the ingot 2 are as follows: Ni is 2.0 wt%, Si is 0.45 wt%, Mn is 0.21 wt%, Zn is 0.1 wt%, and the balance is Cu. The crystal state is an equiaxed crystal phase (a phase in which a columnar crystal and an equiaxed crystal exist simultaneously).
Next, the component values of the ingot 3 are as follows: Ni is 3.8 wt%, Si is 0.8 wt%, Mn is 0.14 wt%, Zn is 0.05 wt%, and the balance is Cu and inevitable impurities. The state was equiaxed crystal phase. After examining the macrostructure of the ingot, the solution treatment was performed in the air as it was or after cold rolling and rapidly cooled in water. The scale was then removed by pickling. Table 1 shows the results of measuring the strength and conductivity by performing the precipitation treatment after the cold wire drawing.
A description will be added in relation to the contents of Table 1. Even if the solution treatment is omitted when the crystal in the metal structure is a single phase, dynamic recrystallization does not occur at a processing rate of 99% or less as in the case of solution treatment at a temperature of 850 ° C. or less. Miniaturization does not occur. Therefore, the strength does not increase. However, if the degree of processing is 99% or more, the strength is 700 N / mm ² or more, and if it is 99.99% or more, the strength is rapidly increased to 850 N / mm ² . However, the conductivity shows a low and similar value when Ni, Si, and Mn are dissolved, indicating that dynamic recrystallization occurs in the solid solution.

  Table 2 shows the relationship between the conditions and the characteristic values when the sample obtained in Example 1 was subjected to the final precipitation treatment.

  Table 2 will be described. When the degree of work 1 is 99% or more, when the precipitation treatment is performed at 400 to 500 ° C., the strength decreases, but the conductivity and the elongation rate approach 6%. When the degree of work 1 is 99.99% or more, the strength reduction is small even if it is as high as 475 ° C. In particular, when the solution treatment temperature is as high as 950 ° C., the conductivity and the elongation are increased, but the strength is decreased. This is because there is no pinning effect of the Ni—Si compound, and the growth rate of crystal grains is high, being 1 to 2 μm.

  The ingot billet of Example 1 was subjected to two conditions: a condition in which the solution treatment was omitted, and a condition in which the solution treatment was performed at 750 ° C. × 3 hours and then rapidly cooled in water. Wire processing was performed and intermediate precipitation treatment was performed. Table 3 shows the relationship between processing conditions and characteristic values.

  Table 3 will be described. What was drawn at a processing degree of 99% or more and subjected to precipitation treatment at 400 to 500 ° C. showed high conductivity, but the strength decreased. In particular, what was carried out at a solution temperature of 950 ° C. showed high conductivity but low strength. This is because the growth rate of crystal grains is high.

Table 4 shows the relationship between the conditions and the characteristic values when the sample obtained in Example 3 was subjected to final precipitation after the final cold drawing at a workability of 2 of 99% or more.
Table 4 will be described. After the final wire drawing of 99% or more of the degree of work 2 is performed, the final precipitation treatment at 300 to 400 ° C. results in a slight decrease in strength, but the conductivity is improved.
Maintains high strength, elongation and electrical conductivity. This is because the crystal grain size does not grow due to the pinning effect of the Ni—Si compound in the final precipitation treatment and ultrafine crystal grains of 0.2 to 0.4 μm are generated. At a final deposition temperature of 375 ° C. or higher, the conductivity increases to 50% or higher, but the strength decreases. Further, when the temperature reaches 450 ° C., the conductivity is as high as 52%, but the strength is greatly reduced to 452 N / mm ² .

  Various test pieces were collected from the round wire obtained by the above fabrication and subjected to material tests, and the crystal grain size, strength, elongation, and conductivity were measured. The crystal grain size was analyzed with an electron microscope. The strength and elongation were measured according to the tensile test specified in JIS2242. The conductivity was determined by measuring the conductivity using the four probe method.

  In the electrical and electronic equipment industries, the reduction of product weight and weight is a global trend. In order to reduce the size of electronic devices, the wires used to connect the devices must be thin and strong. Therefore, in order to increase the strength of the copper alloy used for thin conductors, if the crystal grains in the material structure are made finer, the drawability decreases, so there is a conventional Corson type fine wire with high strength and good drawability. There wasn't. Therefore, in the present invention, as disclosed in detail above, an innovative new Corson-type fine wire that has high strength, high electrical conductivity, and good stretchability was originally developed and provided to the industry in this field. It is what. Therefore, it is clear that the industrial applicability of the present invention is extremely large.

Claims (3)

Ni: 1.0 to 4.8 mass %, Si: 0.2 to 1.4 mass %, Mn: 0.05 to 0.5 mass %, Zn: 1.0 or less mass %, with the balance being Cu In the case of a columnar crystal single-phase structure, the solution is not subjected to solution treatment, and in the case of a structure containing equiaxed crystals, solution treatment is performed at 700 to 950 ° C. Then, cold working is performed and finally cold drawing is performed at a workability of 99% or more, and then a precipitation treatment is performed at a temperature of 250 to 500 ° C. for 5 to 150 minutes. The manufacturing method of the Corson alloy fine wire for electrical machinery and electronic equipment components characterized by making a particle size into 2 micrometers or less.   2. The method for producing a Corson alloy fine wire is one in which an intermediate precipitation treatment step is inserted between a solution treatment step and a cold wire drawing step so that the crystal grain size in the metal structure is 1 μm or less. The manufacturing method of the Corson alloy fine wire for electrical machinery and electronic equipment components as described in 2 ..   The method for producing a Corson alloy fine wire for electric and electronic device parts according to claim 1 or 2, wherein the solution treatment is performed in a state of an ingot of a copper alloy having the above composition.