CN103547692B - Cu-Ni-Si copper alloy sheet with excellent deep drawability and process for producing same - Google Patents

Abstract

A Cu-Ni-Si-based copper alloy plate containing 1.0 to 3.0% by mass of Ni, and containing Si at a concentration of 1/6 to 1/4 of the concentration of Ni by mass %, with the balance being Cu and unavoidable impurities , the arithmetic average roughness Ra of the surface is 0.02-0.2 μm, and the standard deviation of the absolute value of each peak value and valley value is less than 0.1 μm based on the average surface roughness line. The vertical and horizontal dimensions of the grains in the alloy structure The average value of the ratio is 0.4 to 0.6. When the orientation of all pixels within the measurement area is measured according to the EBSD method, and the boundary between adjacent pixels with an orientation difference of 5° or more is regarded as a grain boundary, The average value of all grains of GOS is 1.2-1.5°, the ratio of the total length Lσ of special grain boundaries to the total length L of grain boundaries (Lσ/L) of special grain boundaries is 60-70%, and the elastic limit The value is 450 to 600 N/mm ² , the solder heat peeling resistance at 150°C for 1000 hours is good, there is little variation in fatigue resistance, and it has excellent deep drawability.

Description

Cu-Ni-Si-based copper alloy sheet excellent in deep drawing workability and manufacturing method thereof

technical field

The present invention relates to a Cu-Ni-Si-based copper alloy plate and a manufacturing method thereof. The Cu-Ni-Si-based copper alloy plate can maintain a balance between deep drawing workability, solder heat peeling resistance, and elastic limit value. It has little change in fatigue resistance and has excellent deep drawability, making it suitable for use in electrical and electronic components.

This application claims the priority based on the international application PCT/JP2011/062028 for which it applied on May 25, 2011, and uses the content here.

Background technique

With the lightness, thinner and shorter of electronic equipment in recent years, terminals and connectors are also developing in the direction of miniaturization and thinning, and strength and bending workability are required, so as to replace the conventional solid-solution strengthening such as phosphor bronze or brass The demand for precipitation-strengthened copper alloys such as Corson (Cu-Ni-Si-based) alloys, beryllium copper, and titanium copper is increasing.

Among them, Corson alloy is an alloy in which the solid solution limit of nickel silicide compound to copper changes significantly depending on temperature, and it is a precipitation-hardening type alloy that is solidified by quenching and tempering, and its heat resistance and high-temperature strength are also good. It is also excellent in balance between strength and electrical conductivity, so it has been widely used in various springs for conduction and high tensile strength wires, etc., and has been increasingly used in electronic components such as terminals and connectors in recent years.

In general, strength and bendability are opposite properties, and Corson alloys have been studying ways to improve bendability while maintaining high strength, and extensively adjust the manufacturing process and control the crystal grain size separately or mutually. , the number, shape and texture of precipitates to improve bending workability.

In addition, in order to use Corson alloy in a predetermined shape in various electronic components under harsh environments, it is required to have ease of processing, especially good deep drawing workability and solder heat peeling resistance when used at high temperatures.

Patent Document 1 discloses a Ni that contains 1.0 to 4.0% by mass and Si at a concentration of 1/6 to 1/4 of the Ni concentration, and the frequency of twin boundaries (Σ3 boundaries) in all grain boundaries is 15 to 15 A Cu-Ni-Si based alloy for electronic parts with an excellent balance of 60% strength and bendability.

Patent Document 2 discloses a copper-based precipitation-type alloy sheet as follows. The copper-based precipitation-type alloy sheet is a copper-based precipitation-type alloy sheet for contact materials. The maximum value of the difference between the tensile strength in the direction of 45° angle and the tensile strength in the direction of 90° angle with the rolling direction is 100 MPa or less, containing 2 to 4% by mass Ni and 0.4-1% by mass of Si, if necessary, further contain an appropriate amount of at least one selected from Mg, Sn, Zn and Cr, and the balance is copper and unavoidable impurities. The contact material is manufactured by subjecting a solution-treated copper alloy plate to aging heat treatment with a copper-based precipitation alloy plate, and then performing cold rolling with a rolling ratio of 30% or less, which improves the performance of multi-function switches used in electronic equipment and the like. operability.

Patent Document 3 discloses a Corson (Cu—Ni—Si) copper alloy sheet having a yield strength of 700 N/mm ² or more, an electrical conductivity of 35% IACS or more, and excellent bending workability. The copper alloy sheet contains 2.5% (mass %, the same below) of Ni and 0.5% or more of Ni and less than 1.5% so that the mass ratio Ni/Si of Ni and Si is in the range of 4 to 5. Si further contains 0.01% to less than 4% of Sn, the balance is Cu and unavoidable impurities, the average crystal grain size is 10 μm or less, and has a cubic (Cube) orientation in the measurement results based on the SEM-EBSP method{ 001}<100> is a texture with a ratio of 50% or more, and it is produced by the following steps: After obtaining a solid solution recrystallized structure by continuous annealing, cold rolling with a processing rate of 20% or less and 400 to 600 ° C × 1 Aging treatment for ∼8 hours, followed by final cold rolling with a working ratio of 1 to 20%, followed by short-time annealing at 400 to 550°C for 30 seconds or less.

Patent Document 1: Japanese Patent Laid-Open No. 2009-263784

Patent Document 2: Japanese Patent Laid-Open No. 2008-95186

Patent Document 3: Japanese Patent Publication No. 2006-283059

The deep drawability of conventional Cu-Ni-Si based Corson alloys is not sufficient, and the balance between deep drawability, solder heat peeling resistance and elastic limit value is poor, and the variation (deviation) of fatigue resistance characteristics It is often a hindrance to the application as an electronic component material that is exposed to severe use environments under high temperature and high vibration for a long time.

Contents of the invention

The present invention has been made in view of such circumstances, and provides a Cu-Ni-Si-based copper alloy sheet capable of maintaining deep drawing workability, solder heat detachment resistance, and a manufacturing method thereof. The balance between the elastic limit values, the fluctuation (deviation) of the fatigue resistance is small, and it is used in electrical and electronic parts because of its excellent deep drawing properties.

As a result of intensive research by the present inventors, it has been found that, in the case where Ni is contained in an amount of 1.0 to 3.0% by mass, Si is contained in a concentration of 1/6 to 1/4 of the concentration in mass % of Ni, and the balance is Cu and unavoidable impurities. In the Cu-Ni-Si copper alloy plate, the arithmetic mean roughness Ra of the surface is 0.02-0.2 μm, and the standard deviation of the absolute value of each peak value and valley value is 0.1 μm based on the surface roughness average line Below, the average value of the aspect ratio (short grain diameter/major diameter) of crystal grains in the alloy structure is 0.4 to 0.6, when GOS measured by the EBSD method using a scanning electron microscope with an electron backscatter diffraction imaging system The average value of all the grains is 1.2-1.5°, and the ratio of the total length Lσ of the special grain boundary to the total length L of the grain boundary (Lσ/L) is 60-70%, the elastic limit The value is 450 to 600 N/mm ² , the solder heat peeling resistance at 150° C. for 1000 hours is good, the variation (variation) in the fatigue resistance property is small, and the deep drawing workability also exhibits excellent characteristics.

It was further found that the average value of the aspect ratio (short grain diameter/major diameter of grain) of the crystal grains mainly affects the solder heat peeling resistance at 150°C for 1000 hours, and the average value among all grains of GOS mainly affects The elastic limit value, the ratio (Lσ/L) of the total length Lσ of the special grain boundary of the special grain boundary mainly affects the deep drawing processability, the arithmetic mean roughness Ra of the surface and the peak value and The standard deviation of the absolute value of the valley value affects the variation (variation) of the fatigue resistance property.

In addition, it was also found that the average value of the aspect ratio (short grain diameter/major diameter) of grains basically depends on the processing rate at the time of final cold rolling during production, and the average value among all grains of GOS is basically depends on the tension of the copper alloy sheet in the furnace during continuous low-temperature annealing during manufacturing, and the ratio (Lσ/L) of the total length Lσ of special grain boundaries of special grain boundaries basically depends on the continuous low-temperature annealing during manufacturing. The floating distance of the copper alloy plate in the furnace, the arithmetic mean roughness Ra of the surface and the standard deviation of the absolute values of the peak and valley values based on the average surface roughness basically depend on the process carried out in the manufacturing process. The tension applied to the copper alloy sheet during final cold rolling and the surface roughness of the roll.

The present invention is made based on the above knowledge, and the Cu-Ni-Si-based copper alloy sheet of the present invention is characterized in that it contains 1.0 to 3.0% by mass of Ni, and contains 1/6 to 1/6 of the mass % concentration of Ni. 1/4 Si, the balance is Cu and unavoidable impurities, the arithmetic average roughness Ra of the surface is 0.02-0.2μm, and the absolute value of each peak value and valley value is based on the average surface roughness line The standard deviation is 0.1 μm or less, and the average value of the aspect ratio (short diameter of grains/long diameter of grains) of grains in the alloy structure is 0.4 to 0.6. The EBSD method measures the orientation of all pixels within the measurement area, and when the boundary between adjacent pixels with an orientation difference of 5° or more is regarded as a grain boundary, the average value among all grains of GOS is 1.2 ~1.5°, the ratio of the total length Lσ of the special grain boundary to the total length L of the grain boundary (Lσ/L) is 60-70%, the elastic limit value is 450-600N/mm ² , at 150 °C and 1000 hours, the solder heat-resistant detachment property is good, there is little variation in the fatigue resistance property, and it has excellent deep drawing property.

Ni and Si are appropriately heat-treated to form fine particles of an intermetallic compound mainly composed of Ni ₂ Si. As a result, the strength of the alloy increases significantly, while also improving electrical conductivity.

Ni is added in a range of 1.0 to 3.0% by mass, preferably 1.5 to 2.5% by mass. When Ni is less than 1.0% by mass, sufficient strength cannot be obtained. When Ni exceeds 3.0% by mass, cracks are generated during hot rolling.

The addition concentration (mass %) of Si is 1/6 to 1/4 of the addition concentration (mass %) of Ni. When the Si addition concentration is less than 1/6 of the Ni addition concentration, the strength will decrease. When it is more than 1/4 of the Ni addition concentration, not only the strength is not beneficial, but also the conductivity will be reduced due to the excess Si.

When the average value of the aspect ratio of crystal grains (short diameter of crystal grains/major diameter of crystal grains) is less than 0.4 or exceeds 0.6, the solder heat peeling resistance at 150° C.×1000 hours decreases.

When the average value among all the grains of GOS is less than 1.2° or exceeds 1.5°, a decrease in the elastic limit value is caused.

When the ratio (Lσ/L) of the special grain boundary total length Lσ of the special grain boundary is less than 60% or exceeds 70%, the deep drawing workability is reduced.

When the arithmetic average roughness Ra of the surface exceeds 0.2 μm, fluctuations in fatigue resistance characteristics become large, and when the arithmetic average roughness Ra is less than 0.02 μm, the effect becomes saturated, which wastes manufacturing costs.

When the standard deviation of the absolute value of each peak value and trough value on the basis of the average surface roughness line exceeds 0.1 μm, the variation in the fatigue resistance property becomes large. The smaller the standard deviation, the better, but considering the production cost and effect, it is preferably 0.03 μm or more.

In addition, the Cu—Ni—Si-based copper alloy sheet of the present invention further contains 0.2 to 0.8% by mass of Sn and 0.3 to 1.5% by mass of Zn.

Sn and Zn have the effect of improving strength and heat resistance, especially Sn has the effect of improving stress relaxation resistance, and Zn has the effect of improving soldering heat resistance. Sn is added in the range of 0.2 to 0.8 mass % and Zn in the range of 0.3 to 1.5 mass %. When it is less than the aforementioned range, the desired effect cannot be obtained, and when it exceeds the aforementioned range, a decrease in electrical conductivity will be caused.

In addition, the Cu—Ni—Si-based copper alloy sheet of the present invention is characterized in that it further contains 0.001 to 0.2% by mass of Mg.

Mg has the effect of improving stress relaxation characteristics and hot workability, but if it exceeds 0.2% by mass, castability (decrease in casting surface quality), hot workability, and solder heat peeling resistance will decrease.

In addition, the Cu-Ni-Si-based copper alloy sheet of the present invention is characterized by further containing Fe: 0.007 to 0.25% by mass, P: 0.001 to 0.2% by mass, C: 0.0001 to 0.001% by mass, Cr: 0.001 to 0.3% by mass %, Zr: 0.001 to 0.3% by mass, one or two or more.

Fe has the effect of improving the reliability of the connector by the effect of improving the hot rollability (the effect of suppressing the generation of surface cracks and edge cracks) and the effect of improving the heat-resistant adhesion of plating, which It is improved by the precipitation of Ni and Si compounds, but when the content is less than 0.007%, the above effect cannot obtain the desired effect. On the other hand, when the content exceeds 0.25%, the hot rolling effect is saturated. , On the contrary, there will be a downward trend, and it will also have a bad effect on the conductivity, so its content is set at 0.007-0.25%.

P has the function of suppressing the decrease in elasticity caused by bending processing, thereby improving the insertion and extraction characteristics of the connector obtained through molding processing, and the function of improving migration resistance (may grey-shion characteristics), but when its content is less than 0.001%, On the other hand, when the content exceeds 0.2%, the solder heat peeling resistance is significantly impaired, so the content is set at 0.001 to 0.2%.

C has the function of improving the punching workability, and also has the function of improving the strength of the alloy by making the compound of Ni and Si finer, but when its content is less than 0.0001%, the desired effect cannot be obtained. On the other hand, when When the content exceeds 0.001%, it is not preferable because it will adversely affect hot workability. Therefore, the C content is set at 0.0001 to 0.001%.

The affinity between Cr and Zr and C is strong, and it is easy to include C in the Cu alloy. In addition, it also has the effect of further refining the compound of Ni and Si to improve the strength of the alloy, and further improving the strength of the alloy through its own precipitation. The effect of strength, but when the content of one or both of Cr and Zr is less than 0.001%, the strength improvement effect of the alloy cannot be obtained. On the other hand, when the content exceeds 0.3%, Cr and/or Zr will be generated Larger precipitates lead to deterioration of platability, and also deterioration of punching workability, which in turn impairs hot workability, so it is not preferable. Therefore, the content of one or both of Cr and Zr is set at 0.001 to 0.3%.

In addition, the method for producing a Cu-Ni-Si-based copper alloy sheet according to the present invention is characterized in that the copper alloy sheet is manufactured by processes including hot rolling, cold rolling, solution treatment, aging treatment, final cold rolling, and low-temperature annealing. At the same time, the final cold rolling is carried out under the conditions of a processing rate of 10 to 30%, a tension of 90 to 150 N/mm ² applied to the copper alloy sheet, and a roll ground by a grindstone with a particle size of #180 to 600, and Continuous low-temperature annealing is performed under the conditions that the tension applied to the copper alloy sheet in the furnace is 300-900 N/mm ² , and the floating distance of the copper alloy sheet in the furnace is 10-20 mm.

When the processing ratio in the final cold rolling is less than 10% or exceeds 30%, the average value of the aspect ratio of crystal grains (short diameter of grains/long diameter of grains) does not fall within the range of 0.4 to 0.6.

When the furnace tension applied to the copper alloy sheet during continuous low-temperature annealing is less than 300N/mm ² or exceeds 900N/mm ² , the average value of all grains of GOS does not fall within the range of 1.2° to 1.5°.

When the furnace float distance of the copper alloy plate during continuous low-temperature annealing is less than 10mm or exceeds 20mm, the ratio of the total length Lσ of the special grain boundary to the total length L of the grain boundary (Lσ/L) will not Fall into the range of 60-70%.

When the tension applied to the copper alloy sheet during final cold rolling is less than 90N/ ^mm2 , the standard deviation of the absolute values of the peak and valley values on the basis of the average surface roughness line will exceed 0.1 μm. When it exceeds 150N/mm ² , the effect will be saturated, and the manufacturing cost will be wasted.

When a roll ground by a millstone with a grain size smaller than #180 is used in the final cold rolling, the arithmetic mean roughness Ra of the surface will exceed 0.2μm, and when the grain size exceeds #600, the effect will be saturated and it will be difficult to remove the roughness generated in the manufacturing process surface damage.

According to the present invention, it is possible to provide an electric and electronic component that can maintain a balance between deep drawability, solder heat peeling resistance, and elastic limit value, has little variation in fatigue resistance characteristics, and has excellent deep drawability in particular. A Cu-Ni-Si-based copper alloy plate and a manufacturing method thereof.

Description of drawings

FIG. 1 is a schematic diagram showing an example of continuous low-temperature annealing equipment used in the method for producing a Cu—Ni—Si-based copper alloy sheet of the present invention.

Fig. 2 is a schematic view illustrating the floating distance of the copper plate in the continuous low-temperature annealing furnace used in the method for producing the Cu-Ni-Si-based copper alloy plate of the present invention.

Detailed ways

Next, embodiments of the present invention will be described.

[Composition of Copper Alloy Sheet]

The copper alloy sheet of the present invention has the following composition: in terms of mass %, it contains 1.0 to 3.0 mass % of Ni, and contains Si at a concentration of 1/6 to 1/4 of the mass % concentration of Ni, and the balance is Cu and unavoidable impurities.

Ni and Si form fine particles of an intermetallic compound mainly composed of Ni ₂ Si by performing an appropriate heat treatment. As a result, the strength of the alloy is significantly increased while also improving electrical conductivity.

Ni is added in a range of 1.0 to 3.0% by mass, preferably 1.5 to 2.5% by mass. Sufficient strength cannot be obtained when Ni is less than 1.0% by mass. When Ni exceeds 3.0% by mass, cracks are generated during hot rolling.

The addition concentration (mass %) of Si is 1/6 to 1/4 of the addition concentration (mass %) of Ni. When the added concentration of Si is less than 1/6 of the added concentration of Ni, the strength will decrease, and when it is more than 1/4 of the added concentration of Ni, not only the strength is not beneficial, but also the conductivity will be reduced due to the excess Si.

Moreover, this copper alloy may further contain 0.2-0.8 mass % of Sn and 0.3-1.5 mass % of Zn with respect to the said basic composition.

Sn and Zn have the effect of improving strength and heat resistance, Sn has the effect of improving stress relaxation resistance, and Zn has the effect of improving soldering heat resistance. Sn is added in the range of 0.2 to 0.8 mass % and Zn in the range of 0.3 to 1.5 mass %. When it is less than the aforementioned range, the desired effect cannot be obtained, and when it exceeds the aforementioned range, the conductivity will be lowered.

In addition, the copper alloy may further contain Mg in an amount of 0.001 to 0.2% by mass based on the basic composition described above.

Mg has the effect of improving stress relaxation characteristics and hot workability, and is added in the range of 0.001 to 0.2% by mass. When it exceeds 0.2% by mass, castability (decrease in casting surface quality), hot workability, and solder heat peeling resistance will be reduced.

In addition, the copper alloy may further contain Fe: 0.007 to 0.25% by mass, P: 0.001 to 0.2% by mass, C: 0.0001 to 0.001% by mass, Cr: 0.001 to 0.3% by mass, and Zr: 0.001 to 0.3% by mass, based on the above basic composition. One or more of 0.3% by mass.

Fe has the effect of improving the reliability of the connector by the effect of improving the hot rollability (the effect of suppressing the generation of surface cracks and edge cracks) and the effect of improving the heat-resistant adhesion of plating, which It is improved by the precipitation of Ni and Si compounds, but when the content is less than 0.007%, the above effect cannot obtain the desired effect. On the other hand, when the content exceeds 0.25%, the hot rolling effect is saturated. , On the contrary, there will be a downward trend, and it will also have a bad effect on the conductivity, so its content is set at 0.007-0.25%.

P has the function of suppressing the decrease in elasticity caused by bending processing, thereby improving the insertion and extraction characteristics of the connector obtained through molding processing and the function of improving the migration resistance characteristics, but when its content is less than 0.001%, the desired Effect, on the other hand, when its content exceeds 0.2%, the solder heat peeling resistance is significantly impaired, so its content is set at 0.001 to 0.2%.

C has the function of improving the punching workability, and also has the function of improving the strength of the alloy by making the compound of Ni and Si finer, but when its content is less than 0.0001%, the desired effect cannot be obtained. On the other hand, when When the content exceeds 0.001%, it is not preferable because it will adversely affect hot workability. Therefore, the C content is set at 0.0001 to 0.001%.

The affinity between Cr and Zr and C is strong, and it is easy to include C in the Cu alloy. In addition, it also has the effect of further refining the compound of Ni and Si to improve the strength of the alloy, and further improving the strength of the alloy through its own precipitation. The effect of strength, but when the content of one or both of Cr and Zr is less than 0.001%, the strength improvement effect of the alloy cannot be obtained. On the other hand, when the content exceeds 0.3%, Cr and/or Zr will be generated Larger precipitates lead to poor plating properties, poor punching workability, and further impair hot workability, so it is not preferable. Therefore, the content of one or both of Cr and Zr is set at 0.001 to 0.3%.

In addition, the arithmetic average roughness Ra of the surface of the Cu-Ni-Si-based copper alloy plate is 0.02 to 0.2 μm, and the standard deviation of the absolute values of the respective peak values and trough values when the surface roughness average line is used as a reference is 0.1 μm or less, the average value of the aspect ratio of grains in the alloy structure (short diameter of grains/long diameter of grains) is 0.4 to 0.6. The orientation of all pixels within the measurement area is measured, and when the boundary between adjacent pixels with an orientation difference of 5° or more is used as a grain boundary, the average value in all grains of GOS is 1.2 to 1.5°, The ratio of the total length Lσ of the special grain boundary to the total length L of the grain boundary (Lσ/L) is 60-70%, and the elastic limit value is 450-600N/mm ² , at 150°C and 1000 hours The following solder has good heat peeling resistance, less variation in fatigue resistance, and excellent deep drawing properties.

[Arithmetic mean roughness Ra, standard deviation of absolute values of peak and valley values based on the surface roughness mean line]

The arithmetic mean roughness Ra of the surface of the copper alloy sheet was obtained as follows.

Using a stylus type surface roughness tester (SE-30D) manufactured by Kosaka Research Institute Co., Ltd., the distribution map was obtained according to JI SB0651-1996, and the arithmetic mean roughness (Ra) was calculated based on the distribution map (JISB0601-1994).

The standard deviation of the absolute values of the respective peak values and valley values based on the surface roughness average line of the copper alloy sheet surface was obtained as follows.

Using a stylus-type surface roughness tester (SE-30D) manufactured by Kosaka Laboratories Co., Ltd., obtain a distribution map in accordance with JISB0651-1996, and measure each peak value based on the distribution map based on the average line of surface roughness and the absolute value of the valley value, and calculate its standard deviation.

[Aspect ratio, GOS, Lσ/L]

The average value of the aspect ratio (short diameter of crystal grains/long diameter of grains) of crystal grains in the alloy structure was obtained as follows.

As a pretreatment, after immersing a 10 mm × 10 mm sample in 10% sulfuric acid for 10 minutes, washing it with water, spraying water with a blower, and using a plane milling (ion milling) device manufactured by Hitachi High-Technology Co., Ltd. Under the conditions of accelerating voltage 5kV, incident angle 5°, and irradiation time 1 hour, surface treatment was carried out on the sample after watering.

Next, the surface of the sample was observed using a scanning electron microscope S-3400N manufactured by Hitachi High-Technologies Co., Ltd. with an EBSD system manufactured by TSL Corporation. The observation conditions were an acceleration voltage of 25 kV and a measurement area (rolling direction) of 150 μm×150 μm.

Next, measure the orientation of all pixels in the measurement area with a step size of 0.5 μm, and define the boundary where the orientation difference between pixels is more than 5° as a grain boundary, and the set of two or more pixels surrounded by the grain boundary When regarded as crystal grains, the length in the long axis direction of each crystal grain is defined as a, the length in the minor axis direction is defined as b, and the value obtained by dividing b by a is defined as the aspect ratio. The aspect ratios of all the grains in the measured area were calculated and their average value was calculated.

When the average value of the aspect ratio of crystal grains (short diameter of crystal grains/major diameter of crystal grains) is less than 0.4 or exceeds 0.6, the solder heat peeling resistance at 150° C.×1000 hours decreases.

The average value of all crystal grains of GOS measured by the EBSD method using a scanning electron microscope with an electron backscattered diffraction imaging system is obtained as follows.

As a pretreatment, a sample of 10 mm × 10 mm was immersed in 10% sulfuric acid for 10 minutes, washed with water, and sprayed with a blower. Under the conditions of an angle of 5° and an irradiation time of 1 hour, the surface treatment of the sample after watering was carried out.

Next, the surface of the sample was observed using a scanning electron microscope S-3400N manufactured by Hitachi High-Technologies Co., Ltd. with an EBSD system manufactured by TSL Corporation. The observation conditions were an accelerating voltage of 25 kV and a measurement area of 150 μm×150 μm.

From the observation results, the average value of the average misorientation between all the pixels in the crystal grains of all the crystal grains was obtained under the following conditions.

The orientations of all the pixels within the measurement area were measured at a step size of 0.5 μm, and the boundaries where the orientation difference between adjacent pixels was 5° or more were regarded as grain boundaries.

Next, for all grains surrounded by grain boundaries, the average value of the orientation difference (GOS: Grain Orientation Spread) between all pixels in the grain is calculated by formula (1), and all values The average value is taken as the average misorientation among all pixels within a grain of all grains, ie, the average value in all grains of the GOS. In addition, the one where two or more pixels are connected is referred to as a die.

$\mathrm{<span\; class="notranslate">\; GOS</span>}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; ij</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>}}{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

In the above formula, i and j represent pixel numbers within the crystal grain.

n represents the number of pixels within a die.

α _ij represents the orientation difference of pixels i and j.

When the average value among all the grains of GOS is less than 1.2° or exceeds 1.5°, a decrease in the elastic limit value is caused.

From the ratio (Lσ/L) of the total grain boundary length Lσ of the special grain boundary to the total grain boundary length L of the grain boundary measured by the EBSD method using a scanning electron microscope with an electron backscattered diffraction image system, it is calculated as follows have to. The special grain boundary is a grain boundary defined in crystallography according to the CSL theory (Krongerg et.al.: Trans. Met. Soc. AIME, 185, 501 (1949)) with a Σ value of 3≦Σ≦29 (heavy site lattice grain boundary ), which is defined as the grain boundary where the lattice orientation defect Dq of the inherent corresponding part in the grain boundary satisfies Dq≦15°/Σ ^1/2 (DGBrandon: Acta.Metallurgica.Vol.14, p1479, 1966).

As a pretreatment, a sample of 10 mm × 10 mm was immersed in 10% sulfuric acid for 10 minutes, washed with water, and sprayed with a blower. Under the conditions of an angle of 5° and an irradiation time of 1 hour, the surface treatment of the sample after watering was carried out.

Next, the surface of the sample was observed using a scanning electron microscope S-3400N manufactured by Hitachi High-Technologies Co., Ltd. with an EBSD system manufactured by TSL Corporation. The observation conditions were an accelerating voltage of 25 kV and a measurement area of 150 μm×150 μm.

The orientations of all the pixels within the measurement area were measured at a step size of 0.5 μm, and the boundaries where the orientation difference between adjacent pixels was 5° or more were regarded as grain boundaries.

Next, the total grain boundary length L of the grain boundaries within the measurement range is measured, and the position of the grain boundary where the interface of adjacent grains constitutes a special grain boundary is determined, and the total length Lσ of the special grain boundary is obtained The grain boundary length ratio Lσ/L of the total grain boundary length L of the grain boundaries measured above was used as the special grain boundary length ratio.

When the ratio (Lσ/L) of the special grain boundary total length Lσ of the special grain boundary is less than 60% or exceeds 70%, the deep drawing workability is reduced.

[Manufacturing method]

The method for producing a Cu-Ni-Si-based copper alloy sheet according to the present invention is characterized in that when the copper alloy sheet is produced by processes including hot rolling, cold rolling, solution treatment, aging treatment, final cold rolling, and low-temperature annealing, The final cold rolling is carried out under the conditions of a processing rate of 10 to 30%, a tension of 90 to 150 N/mm ² applied to the copper alloy sheet, and a roll ground by a grindstone with a particle size of #180 to 600, and the The continuous low-temperature annealing is carried out under the conditions that the tension applied to the copper alloy sheet in the furnace is 300-900 N/mm ² , and the floating distance of the copper alloy sheet in the furnace is 10-20 mm.

When the processing rate in the final cold rolling is less than 10% or exceeds 30%, the average value of the grain aspect ratio (short grain diameter/grain major diameter) will not fall within the range of 0.4 to 0.6, resulting in Decrease in solder heat peel resistance.

When the furnace tension given to the copper alloy plate during continuous low-temperature annealing is less than 300N/ ^mm2 or exceeds 900N/ ^mm2 , the average value of all grains of GOS will not fall within the range of 1.2° to 1.5°, which will cause Decrease in elastic limit value.

When the floating distance of the copper alloy plate in the furnace during continuous low-temperature annealing is less than 10mm or exceeds 20mm, the ratio of the total length Lσ of the special grain boundary to the total length L of the grain boundary (Lσ/L) is not If it falls within the range of 60 to 70%, it will lead to a decrease in deep drawing workability.

When the tension applied to the copper alloy sheet during final cold rolling is less than 90N/ ^mm2 , the standard deviation of the absolute values of the peak and valley values on the basis of the average surface roughness line will exceed 0.1 μm. When it exceeds 150N/mm ² , the effect will be saturated, and the manufacturing cost will be wasted.

When a roll ground by a millstone with a grain size smaller than #180 is used in the final cold rolling, the arithmetic mean roughness Ra of the surface will exceed 0.2μm, and when the grain size exceeds #600, the effect will be saturated and it will be difficult to remove the roughness generated in the manufacturing process surface damage.

An example of continuous low-temperature annealing equipment used in the production method of the present invention is shown in FIG. 1 . The copper alloy sheet F wound on the uncoiler 11 after the final cold rolling is applied with a predetermined tension by the tension control device 12 and the tension control device 14, and is annealed at a low temperature at a predetermined temperature and time in the horizontal annealing furnace 13, It is wound on a tension coiler 16 via a grinding and pickling device 15 .

The furnace floating distance of the copper alloy sheet F during continuous low-temperature annealing in the present invention is the wave height value of the copper alloy sheet F that is waved by the hot air G in the furnace as shown in FIG. 2 . In FIG. 2 , the copper alloy plate F undulates in a wave with a span L, and the height taken from the center of this wave is called a floating distance H. The floating distance H can be controlled by the tension applied to the copper alloy sheet F by the tension control devices 12 and 14 and the amount of hot air G blown to the copper alloy sheet F in the annealing furnace 13 .

As an example of a specific production method, the following methods are mentioned.

Firstly, materials are prepared to become the Cu-Ni-Si-based copper alloy plate of the present invention, which is melted and casted in a low-frequency melting furnace with a reducing atmosphere to obtain a copper alloy ingot. Next, after heating this copper alloy ingot to 900-980 degreeC, it hot-rolls and makes it into the hot-rolled sheet of appropriate thickness, and after water-cooling this hot-rolled sheet, both surfaces are suitably face-milled. Next, cold rolling is performed at a rolling reduction rate of 60 to 90% to produce a cold-rolled sheet having an appropriate thickness, and then continuous annealing is performed at 710 to 750° C. for 7 to 15 seconds under maintenance conditions. Next, after pickling and surface grinding the continuous annealed copper plate, cold rolling is performed at a rolling reduction rate of 60 to 90% to produce a cold-rolled sheet with an appropriate thickness. Next, after maintaining the cold-rolled sheet at 710-780° C. for 7 to 15 seconds, quenching and solution treatment are carried out, and then at 430-470° C. for three hours, precipitation aging treatment is carried out, and then pickling treatment is carried out. Furthermore, the final cold rolling is carried out under the conditions of a processing rate of 10 to 30%, a tension of 90 to 150 N/mm ² applied to the copper alloy plate, and a roll ground by a grindstone with a particle size of #180 to 600, and the steel sheet is rolled in the opposite furnace. The continuous low-temperature annealing is carried out under the conditions that the tension provided by the inner copper alloy plate is 300-900 N/mm ² , and the floating distance of the copper alloy plate in the furnace is 10-20 mm.

Example

The materials were prepared to have the composition shown in Table 1, melted in a low-frequency melting furnace with a reducing atmosphere, and then cast into a copper alloy ingot with a thickness of 80 mm, a width of 200 mm, and a length of 800 mm. After heating this copper alloy ingot to 900-980 degreeC, the hot-rolled plate of thickness 11mm was formed by hot rolling, and after water-cooling this hot-rolled plate, the end faces of both surfaces were cut by 0.5 mm. Next, cold rolling is carried out at a rolling rate of 87% to produce a cold-rolled sheet with a thickness of 1.3mm, and then continuous annealing is carried out at 710-750°C for 7-15 seconds, followed by pickling and surface grinding. Furthermore, cold rolling was performed at a rolling reduction of 77% to produce a cold-rolled sheet having a thickness of 0.3 mm.

After maintaining the cold-rolled sheet at 710-780° C. for 7 to 15 seconds, it was quenched to implement solution treatment, and then maintained at 430-470° C. for three hours to implement precipitation aging treatment and pickling treatment. Under the conditions shown in 1, final cold rolling and continuous low-temperature annealing were carried out to produce copper alloy sheets.

Next, for each sample obtained, the arithmetic mean roughness Ra, the standard deviation of the absolute value of each peak value and valley value based on the surface roughness average line, the aspect ratio, and all GOS values were measured. Average value in grains, ratio of special grain boundary total length Lσ to grain boundary total grain boundary length L (Lσ/L), deep drawing workability, elastic limit value, solder heat peeling resistance, Average value of fatigue properties, standard deviation of fatigue properties.

The arithmetic mean roughness Ra of the surface of the copper alloy plate is obtained as follows.

Using a stylus-type surface roughness tester (SE-30D) manufactured by Kosaka Laboratories Co., Ltd., a distribution map was obtained according to JISB0651-1996, and the arithmetic mean roughness (Ra) (JISB0601-1994) was calculated based on the distribution map.

The standard deviation of the absolute values of the respective peak values and valley values based on the average surface roughness line of the surface of the copper alloy sheet was obtained as follows.

Using the stylus type surface roughness tester (SE-30D) manufactured by Kosaka Research Institute Co., Ltd., the distribution map is obtained according to JISB0651-1996, and based on the distribution map, each peak value and The absolute value of the valley value and its standard deviation is calculated.

The average value of the aspect ratio was obtained as follows.

As a pretreatment, a sample of 10 mm × 10 mm was immersed in 10% sulfuric acid for 10 minutes, washed with water, and sprayed with a blower. Under the conditions of an angle of 5° and an irradiation time of one hour, the surface treatment was performed on the sample after watering.

Next, the surface of the sample was observed using a scanning electron microscope S-3400N manufactured by Hitachi High-Technologies Co., Ltd. with an EBSD system manufactured by TSL Corporation. The observation conditions were an acceleration voltage of 25 kV and a measurement area (rolling direction) of 150 μm×150 μm.

Next, measure the orientation of all pixels in the measurement area with a step size of 0.5 μm, and define the boundary where the orientation difference between pixels is more than 5° as a grain boundary, and define the grain boundaries of two or more pixels surrounded by grain boundaries When the aggregate is regarded as crystal grains, the length in the major axis direction of each crystal grain is defined as a, the length in the minor axis direction is defined as b, and the value obtained by dividing the b by the a is defined as the aspect ratio, The aspect ratios of all crystal grains in the measurement area were obtained, and the average value thereof was calculated.

The average value among all the crystal grains of GOS was obtained as follows.

As a pretreatment, a sample of 10 mm × 10 mm was immersed in 10% sulfuric acid for 10 minutes, washed with water, and sprayed with a blower. Under the conditions of an angle of 5° and an irradiation time of one hour, the surface treatment of the sample after watering was carried out.

Next, the surface of the sample was observed using a scanning electron microscope S-3400N manufactured by Hitachi High-Technologies Co., Ltd. with an EBSD system manufactured by TSL Corporation. The observation conditions were an accelerating voltage of 25 kV and a measurement area of 150 μm×150 μm.

From the observation results, the average value of the average misorientation between all the pixels in the crystal grains among all the crystal grains was found under the following conditions.

The orientations of all the pixels within the measurement area were measured at a step size of 0.5 μm, and the boundaries where the orientation difference between adjacent pixels was 5° or more were regarded as grain boundaries.

Next, for all the grains surrounded by grain boundaries, the average value of the orientation difference (GOS: Grain Orientation Spread) between all pixels in the grain is calculated by formula (1), and all values of The average value is taken as the average misorientation between all pixels within a grain in all grains, ie, the average value in all grains of the GOS. In addition, the one where two or more pixels are connected is referred to as a die.

$\mathrm{<span\; class="notranslate">\; GOS</span>}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; ij</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>}}{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; .</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

In the above formula, i and j represent pixel numbers within the crystal grain.

n represents the number of pixels within a die.

α _ij represents the orientation difference of pixels i and j.

The ratio (Lσ/L) of the special grain boundary total length Lσ of the special grain boundary to the grain boundary total length L of the grain boundary is obtained as follows.

As a pretreatment, a sample of 10 mm × 10 mm was immersed in 10% sulfuric acid for 10 minutes, washed with water, and sprayed with a blower. Under the conditions of an angle of 5° and an irradiation time of one hour, the surface treatment of the sample after watering was carried out.

Next, the surface of the sample was observed using a scanning electron microscope S-3400N manufactured by Hitachi High-Technologies Co., Ltd. with an EBSD system manufactured by TSL Corporation. The observation conditions were an accelerating voltage of 25 kV and a measurement area of 150 μm×150 μm.

The orientations of all the pixels within the measurement area were measured at a step size of 0.5 μm, and the boundaries where the orientation difference between adjacent pixels was 5° or more were regarded as grain boundaries.

Next, the total grain boundary length L of the grain boundaries within the measurement range is measured, and the position of the grain boundary where the interface of adjacent grains constitutes a special grain boundary is determined, and the total length Lσ of the special grain boundary is obtained The grain boundary length ratio Lσ/L of the total grain boundary length L of the grain boundaries measured above was used as the special grain boundary length ratio.

The deep drawing workability was obtained as follows.

Using a testing machine made by Ericsson Corporation, under the conditions of punching hole diameter: Φ10mm, lubricant: lubricating oil, make cups, observe the appearance, set good as ○, and produce defects on the flange Or cracks were set to x.

The elastic limit value was obtained as follows.

According to JIS-H3130, the permanent deflection is measured by a moment test, and Kb0.1 in R.T. is calculated (corresponding to the maximum surface stress value on the fixed end with a permanent deflection of 0.1mm).

Solder heat peeling resistance was obtained as follows.

Each of the obtained samples was cut into a rectangle having a width of 10 mm and a length of 50 mm, and was dipped in 60%Sn-40%Pb solder at 230°C±5°C for five seconds. The flux uses 25% rosin-ethanol. The material was heated at 150° C. for 1000 hours, bent at 90° with the same radius of curvature as the thickness of the plate, and returned to its original shape. The presence or absence of peeling of the solder at the bent portion was observed with the naked eye.

The average value of the fatigue properties and the standard deviation of the fatigue properties were obtained as follows.

The fatigue test was performed on a rectangular test piece with a width of 10 mm in a direction parallel to the rolling direction in accordance with JIS Z2273. The fatigue life (the number of repeated vibrations until the test piece breaks) where the maximum additional stress (stress on the fixed end) on the surface of the test piece is 400 MPa was measured. Four determinations were performed under the same conditions, and the standard deviation of the four determination values was calculated.

These measurement results are shown in Table 2.

As can be seen from Table 2, the Cu-Ni-Si-based copper alloy of the present invention can maintain a balance between deep drawing workability, solder heat detachment resistance, and elastic limit value, has little variation in fatigue resistance, and has excellent deep drawing properties. Deep processability, suitable for use in electronic components exposed to severe operating environments under high temperature and high vibration for a long time.

As mentioned above, although the manufacturing method of embodiment of this invention was demonstrated, this invention is not limited to the said description, Various changes are possible in the range which does not deviate from the summary of this invention.

Industrial Applicability

The Cu-Ni-Si-based copper alloy plate of the present invention is suitable for use in electronic components exposed to severe operating environments under high temperature and high vibration for a long time.

Symbol Description

11 Uncoiler 12 Tension control device

13 Horizontal annealing furnace 14 Tension control device

15 Grinding and Pickling Device 16 Tension Coiler

F Copper alloy plate G Hot air

Claims (6)

1. A Cu-Ni-Si series copper alloy plate containing 1.0 to 3.0% by mass of Ni, and Si with a concentration of 1/6 to 1/4 of the mass % concentration of Ni, with the remainder being Cu and unavoidable impurities, the arithmetic mean roughness Ra of the surface is 0.02-0.2 μm, and the standard deviation of the absolute values of the peak and valley values is below 0.1 μm based on the average surface roughness line. The aspect ratio, that is, the average value of the grain short diameter/grain long diameter is 0.4 to 0.6, when the orientation of all the pixels within the measurement area is measured by the EBSD method using a scanning electron microscope with an electron backscatter diffraction imaging system Measured, and when the boundary with a misorientation of 5° or more between adjacent pixels is regarded as a grain boundary, the average value of all grains of GOS expressed by the following formula is 1.2 to 1.5°, and the special grain boundary The ratio of the total grain boundary length Lσ to the total grain boundary length L of the grain boundary, that is, Lσ/L, is 60 to 70%, the elastic limit value is 450 to 600 N/mm ² , and the solder heat resistance at 150°C for 1000 hours Good peelability, little change in fatigue resistance, excellent deep drawability, $\mathrm{<span\; class="notranslate">\; GOS</span>}<span\; class="notranslate">\; =</span>\frac{\underset{\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; ,</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; 1</span>}}{\overset{\mathrm{<span\; class="notranslate">\; no</span>}}{\mathrm{<span\; class="notranslate">\; \&Sigma;</span>}}}{\mathrm{<span\; class="notranslate">\; \&alpha;</span>}}_{\mathrm{<span\; class="notranslate">\; ij</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; i</span>}<span\; class="notranslate">\; \&NotEqual;</span>\mathrm{<span\; class="notranslate">\; j</span>}<span\; class="notranslate">\; )</span>}}{\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; no</span>}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>}<span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; \&Center\; Dot;</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$ In the above formula, i and j represent the number of pixels in the crystal grain, n represents the number of pixels in the crystal grain, and α _ij represents the orientation difference between pixels i and j. 2. The Cu-Ni-Si based copper alloy sheet according to claim 1, further comprising 0.2 to 0.8% by mass of Sn and 0.3 to 1.5% by mass of Zn. 3. The Cu-Ni-Si-based copper alloy sheet according to claim 1, further comprising 0.001 to 0.2% by mass of Mg. 4. The Cu-Ni-Si-based copper alloy sheet according to claim 2, further comprising 0.001 to 0.2% by mass of Mg. 5. The Cu-Ni-Si-based copper alloy sheet according to any one of claims 1 to 4, further comprising Fe: 0.007 to 0.25% by mass, P: 0.001 to 0.2% by mass, C: One or more of 0.0001 to 0.001% by mass, Cr: 0.001 to 0.3% by mass, and Zr: 0.001 to 0.3% by mass. 6. A method for manufacturing a Cu-Ni-Si-based copper alloy plate, characterized in that, for the method of manufacturing the Cu-Ni-Si-based copper alloy plate according to claim 1, When the copper alloy sheet is produced by successively including hot rolling, cold rolling, solution treatment, aging treatment, final cold rolling and low temperature annealing, the tension given to the copper alloy sheet is 90~30% at a working rate of 10~30%. 150N/mm ² , and using rolls ground by grindstones with a particle size of #180-600, the final cold rolling is carried out, and the tension given to the copper alloy sheet in the furnace is 300-900N/mm ² , and the copper alloy sheet in the furnace is Continuous low-temperature annealing is carried out under the condition that the floating distance of the alloy plate is 10-20 mm.