High-conductivity low-beryllium copper alloy strip for electroplating and preparation method thereof

Abstract

The invention discloses a high-conductivity low-beryllium copper alloy strip for electroplating and a preparation method of the high-conductivity low-beryllium copper alloy strip, and relates to the technical field of preparation of beryllium copper alloys for electroplating. The high-conductivity low-beryllium copper alloy strip for electroplating comprises the following components in percentage by mass: 0.2%-0.4% of Be, 0.4%-0.6% of Co, 0.05%-0.2% of Ni, 0.1%-0.3% of Ag, 0.05%-0.1% of Zr and the balance of Cu. The preparation method comprises the steps of homogenizing annealing, hot rolling, multiple times of normal-temperature rolling, multiple times of cleaning and brushing, solid solution, aging and the like. According to the product, the conductivity of the beryllium-copper alloy strip is improved by a method for increasing the silver content by reducing the beryllium content. Furthermore, according to the preparation method disclosed by the invention, the surface roughness of the strip is increased by adding a plurality of normal-temperature rolling, a plurality of cleaning, brushing and grinding processes and a grinding process after homogenizing annealing and hot rolling, so that the electroplating effect of the strip is better.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of beryllium copper alloy for electroplating, and in particular relates to a high-conductivity low-beryllium copper alloy strip for electroplating and a preparation method thereof. Background Art

[0002] Beryllium copper alloy is a typical precipitation-strengthened copper alloy. It is the only nonferrous alloy with good combination of mechanical properties, physical properties, chemical properties and corrosion resistance. It is classified into high-strength high-beryllium copper alloy (Be: 1.8-2.1%) and high-conductivity low-beryllium copper alloy (Be: 0.2-0.7%) according to the beryllium content. Its mechanical properties are closely related to its alloy composition, processing conditions and heat treatment. Beryllium bronze has good processing properties after heat treatment and can be processed by rolling, extrusion and other methods.

[0003] Low beryllium copper alloy has excellent properties such as high conductivity, corrosion resistance, fatigue resistance, small elastic hysteresis, non-magnetic, and stress relaxation resistance. It is mainly used in occasions that require good heat dissipation and current carrying, such as aerospace, radar systems, and electrical contact components for ships and vessels; mobile phone battery terminals, SIM card connectors, B / C connectors, miniature handset terminals, etc.; automotive relays, line speed connectors, temperature sensor terminals, etc.

[0004] With the continuous development of 5G communication technology and new energy vehicles in my country, the use of high-conductivity low-beryllium copper alloy strips for electroplating is also increasing. At present, the tensile strength of domestic low-beryllium copper alloy strips is about 650-750MPa, and the conductivity is about 45% IACS. The conductivity is generally on the lower limit, and the coating is uneven after electroplating. Domestic low-beryllium copper strip products are basically dependent on imports, which seriously restricts the development of my country's high-end manufacturing industry. Therefore, in order to improve the competitiveness and market share of domestic high-conductivity low-beryllium copper alloy strips in the domestic market, strengthen the research and development of high-conductivity low-beryllium copper alloy strip preparation technology for electroplating, and independently develop high-conductivity low-beryllium copper alloy strip products with high quality, high conductivity and excellent electroplating performance, which is of strategic and practical significance.

[0005] Therefore, the existing technology needs to be improved. Summary of the invention

[0006] In order to solve the above technical problems, the present invention provides a high-conductivity low-beryllium copper alloy strip for electroplating and a preparation method thereof, wherein the product improves the conductivity of the beryllium copper alloy strip by reducing the beryllium content and increasing the silver content. Furthermore, the preparation method of the present invention increases the surface roughness of the strip by adding multiple room temperature rolling and multiple cleaning, brushing and grinding processes after homogenization annealing and hot rolling, so that the electroplating effect of the strip is better.

[0007] The first aspect of the present invention provides a high-conductivity low-beryllium copper alloy strip for electroplating, which comprises, by mass percentage, Be: 0.2%-0.4%, Co: 0.4%-0.6%, Ni: 0.05%-0.2%, Ag: 0.1-0.3%, Zr: 0.05%-0.1%, and the balance is Cu.

[0008] The high-conductivity low-beryllium copper alloy strip for electroplating according to the first aspect of the present invention comprises, by mass percentage, Be: 0.25%-0.35%, Co: 0.45%-0.55%, Ni: 0.05%-0.15%, Ag: 0.1-0.2%, Zr: 0.05-0.08%, and the remainder is Cu.

[0009] The second aspect of the present invention provides a method for preparing the aforementioned high-conductivity low-beryllium copper alloy strip for electroplating, the preparation method comprising the following steps:

[0010] Step S1, placing the low-beryllium copper alloy ingot obtained by melting and casting into a walking beam heating furnace for homogenization annealing; wherein the temperature of the insulation zone is 900-950°C, the insulation time is 6-10h, and the temperature of the heating zone is 20°C higher than the temperature of the insulation zone;

[0011] Step S2, placing the ingot after homogenization annealing on the roller table of a hot rolling mill for multiple hot rolling, and then water cooling on the roller table of the hot rolling mill to obtain a strip; wherein the final rolling temperature is not less than 750° C.;

[0012] Step S3, milling the upper and lower surfaces and both side edges of the strip blank;

[0013] Step S4, subjecting the milled strip to a first multi-pass normal temperature rolling, and then cleaning and brushing the strip after cutting off the cracked edge of the strip; wherein the total rolling deformation of the first multi-pass normal temperature rolling is not less than 90%;

[0014] Step S5, under the protection of mixed gas, the strip blank after the first cleaning and brushing is placed in a continuous quenching furnace for solution treatment, then the strip blank is gas cooled, and then the strip blank is cleaned and brushed for the second time; wherein the solution temperature is 930-950°C, and the speed of the strip blank passing through the continuous quenching furnace is 5-40m / min;

[0015] Step S6, performing a second multi-pass room temperature rolling on the strip after the second cleaning and brushing, and then performing a third cleaning and brushing on the strip to obtain a strip of finished size; wherein the total rolling deformation of the second multi-pass room temperature rolling is 30%-80%, and the rolling deformation of each pass is greater than 15%;

[0016] Step S7, straightening the strip for the first time so that the warping degree of the strip is less than 10 mm / m and the transverse warping height is less than 1 mm;

[0017] Step S8, subjecting the straightened strip to aging treatment under the protection of mixed gas, and then cooling it to below 40°C before taking it out of the furnace; wherein the aging temperature is 380-480°C, and the holding time is 5-10h;

[0018] Step S9, using 600-1000 mesh and 2000-3000 mesh grinding rollers to clean and grind the strip after aging treatment; wherein the grinding speed is 5-30 m / min;

[0019] Step S10, the cleaned and ground strip is straightened for the second time and cut into strips to obtain a high-conductivity low-beryllium copper alloy strip for electroplating.

[0020] According to the method for preparing a high-conductivity low-beryllium copper alloy strip for electroplating described in the second aspect of the present invention, in the step S1, the preparation process of the low-beryllium copper alloy ingot is as follows:

[0021] Electrolytic copper, electrolytic cobalt and electrolytic nickel are added to the smelting furnace in sequence and then evacuated to a vacuum degree of less than 10 -3 After the copper, cobalt and nickel are completely melted, argon is introduced into the smelting furnace to normal pressure. Beryllium copper master alloy, copper-zirconium master alloy and silver powder are added in sequence under the protective atmosphere of argon, and then vacuum is pumped again until the vacuum degree is less than 10 -3 After Pa, vacuum melting is continued. After all the raw materials are melted, the alloy melt is magnetically stirred while maintaining the melting temperature unchanged. Then, it is allowed to stand and be kept warm for 0.5-1h. Argon is introduced again to normal pressure. Under the protective atmosphere of argon, the alloy melt is cast into an electromagnetically stirred crystallizer. After cooling, a low-beryllium copper alloy ingot is obtained.

[0022] Among them, the melting temperature is 1200-1300℃, the casting temperature is 1160-1220℃, the casting speed is 35-50mm / min, the cooling water temperature for cooling the crystallizer is less than 30℃, and the cooling water flow rate is 40-50m 3 / h.

[0023] According to the method for preparing a high-conductivity, low-beryllium copper alloy strip for electroplating described in the second aspect of the present invention, in the step S2, the first pass processing rate of the multiple passes of hot rolling is 14-15%, and the processing rate of each subsequent pass is 20-35%, and the total processing rate is 91-93%;

[0024] The cooling water temperature is room temperature during water cooling, and the cooling water flow rate is 10-15m 3 / h.

[0025] According to the method for preparing a high-conductivity, low-beryllium copper alloy strip for electroplating described in the second aspect of the present invention, in the step S3, the upper and lower surfaces of the strip are milled by 0.5-1.0 mm, and the two side edges are milled by 5-10 mm, and the milling speed is less than 4 m / min.

[0026] According to the method for preparing a high-conductivity, low-beryllium copper alloy strip for electroplating described in the second aspect of the present invention, the specific process of the first cleaning and brushing, the second cleaning and brushing, or the third cleaning and brushing is as follows:

[0027] After spraying degreasing agent on the surface of the strip, brush it and then rinse it with water. After immersing the washed strip in pickling agent, use brush rollers with different meshes to brush the surface of the strip for pickling. After rinsing it with water again, spray passivation liquid on the surface of the strip and dry and reel it.

[0028] The temperature of the degreasing agent, pickling agent or passivating solution is not lower than 70°C.

[0029] According to the method for preparing a high-conductivity, low-beryllium copper alloy strip for electroplating described in the second aspect of the present invention, the degreasing agent is a sodium carbonate aqueous solution with a mass concentration of 1-2%;

[0030] The pickling agent is a mixed solution of sulfuric acid, hydrogen peroxide and deionized water in a volume ratio of 2:1:(3-4), wherein the mass concentration of the sulfuric acid is 98% and the mass concentration of the hydrogen peroxide is 30%;

[0031] The passivation solution is an aqueous solution of benzotriazole with a mass concentration of 0.2-0.5%.

[0032] According to the method for preparing a high-conductivity, low-beryllium copper alloy strip for electroplating described in the second aspect of the present invention, the brush roller is a diamond brush roller with a mesh size of 240 mesh, 500 mesh or 800 mesh.

[0033] According to the method for preparing a high-conductivity, low-beryllium copper alloy strip for electroplating as described in the second aspect of the present invention, the mixed gas includes hydrogen and nitrogen;

[0034] Among them, hydrogen accounts for 70-73% of the volume of the mixed gas.

[0035] The solution proposed by the present invention has the following technical effects:

[0036] The product of the invention improves the conductivity of the beryllium copper alloy strip by reducing the beryllium content and increasing the silver content.

[0037] In addition, the preparation method of the present invention increases the surface roughness of the strip by adding multiple room temperature rolling and multiple cleaning, brushing and grinding processes after homogenization annealing and hot rolling, so that the coating of the strip after electroplating is more uniform.

[0038] In addition, the low-beryllium copper alloy of the present invention has a tensile strength of 750-950 MPa, a conductivity of 50-60% IACS, an elongation of 10-15%, and a simple preparation process, thereby realizing mass production. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0040] In a first aspect, the present embodiment provides a high-conductivity, low-beryllium copper alloy strip for electroplating, which comprises, by mass percentage, Be: 0.2%-0.4%, Co: 0.4%-0.6%, Ni: 0.05%-0.2%, Ag: 0.1-0.3%, Zr: 0.05%-0.1%, and the remainder is Cu.

[0041] In some embodiments, the alloy comprises, by mass percentage, 0.25%-0.35% Be, 0.45%-0.55% Co, 0.05%-0.15% Ni, 0.1-0.2% Ag, 0.05-0.08% Zr, and the balance is Cu.

[0042] The functions of the elements added in this embodiment are as follows:

[0043] Co: mainly combines with beryllium to form BeCo intermediate compounds, inhibits grain boundary reactions, avoids inhomogeneity caused by over-aging, hinders grain growth during alloy heating, delays solid solution decomposition, and makes the aging process of aging alloy materials easier to control, but excessive cobalt will reduce the strength and conductivity of beryllium copper alloy. Therefore, in this embodiment, the Co content is 0.4%-0.6%, preferably 0.45%-0.55%.

[0044] Ni: A small amount of nickel can sharply reduce the solubility of beryllium in copper, and can also form NiBe precipitation phase with beryllium to inhibit grain growth and grain boundary discontinuous reaction, but too much nickel will cause the β phase to appear in the alloy, which seriously affects the stress relaxation resistance and fatigue performance of the alloy. Therefore, in this embodiment, the Ni content is 0.05%-0.2%, preferably 0.05%-0.15%.

[0045] Zr: has little effect on the electrical conductivity of copper alloys. A small amount of zirconium can refine the grains, form fine dispersed precipitation phases, increase the recrystallization temperature, and reduce the harmful effects of fusible impurities. It can also significantly increase the softening temperature of copper alloys and improve the high-temperature plasticity of alloys. However, excessive zirconium will significantly increase the corrosion rate of the alloy, thereby reducing the performance and durability of the alloy. Therefore, in this embodiment, the Zr content is 0.05%-0.1%, preferably 0.05-0.08%.

[0046] Ag: Silver has the least effect on the electrical conductivity of copper alloys, can improve the strength of the alloy after aging, and maintain high electrical conductivity, significantly improve the alloy recrystallization temperature, creep strength and high temperature thermal low cycle fatigue stability, but excessive silver will reduce the electrical conductivity of beryllium copper alloys. Therefore, in this embodiment, the Ag content is 0.1-0.3%, preferably 0.1-0.2%.

[0047] The second aspect of this embodiment proposes a method for preparing the aforementioned high-conductivity, low-beryllium copper alloy strip for electroplating, by adding multiple room temperature rolling and multiple cleaning, brushing and grinding processes after homogenization annealing and hot rolling to increase the surface roughness of the strip, so that the coating of the strip after electroplating is more uniform.

[0048] The preparation method comprises the following steps:

[0049] Step S1, placing the low-beryllium copper alloy ingot obtained by melting and casting into a walking beam heating furnace for homogenization annealing, wherein the temperature of the insulation zone is 900-950°C, the insulation time is 6-10h, and the temperature of the heating zone is 20°C higher than the temperature of the insulation zone.

[0050] This embodiment adopts a homogenization annealing (continuous annealing) process to homogenize the composition of the low beryllium copper alloy ingot and reduce the segregation between the ingot components. The homogenization annealing temperature in this embodiment is 0.90-0.95TM (TM is the actual temperature at which the ingot begins to melt).

[0051] Step S2, placing the ingot after homogenization annealing on the roller table of the hot rolling mill for multiple hot rolling, and then water cooling on the roller table of the hot rolling mill to obtain a strip, wherein the final rolling temperature is not less than 750°C.

[0052] After hot rolling, the beryllium copper alloy needs to be water-cooled, and the final rolling temperature is not lower than 750°C to ensure the quenching effect brought about by the sudden drop in alloy temperature, so that more precipitates are dissolved in the matrix, the strength of the strip is reduced, and the plasticity is improved, which is conducive to subsequent room temperature rolling.

[0053] Step S3, milling the upper and lower surfaces and both side edges of the strip blank until there are no obvious defects.

[0054] Step S4, the milled strip is subjected to the first multi-pass normal temperature rolling, and then the cracked edge of the strip is cut off and the strip is subjected to the first cleaning and brushing. The total rolling deformation of the first multi-pass normal temperature rolling is not less than 90% to reduce energy consumption.

[0055] Step S5, under the protection of mixed gas, the strip blank after the first cleaning and brushing is placed in a continuous quenching furnace for solution treatment, then the strip blank is gas cooled, and then the strip blank is cleaned and brushed for the second time; wherein, the solution temperature is 930-950°C, and the speed of the strip blank passing through the continuous quenching furnace is 5-40m / min.

[0056] After the first multi-pass room temperature rolling, the strip will inevitably produce work hardening. If the second multi-pass room temperature rolling is directly carried out, the strip will crack at the edge, the rolling force will be too large, or even unable to roll. After the solid solution treatment, the internal grains of the alloy will be restored and recrystallized again, making the strip machinable. The purpose of the first cleaning and brushing process before and after the solid solution treatment and the second cleaning and brushing process is to remove impurities on the surface of the strip and to increase the roughness of the alloy microstructure for subsequent electroplating of the finished product.

[0057] Step S6, subjecting the strip after the second cleaning and brushing to a second multi-pass room temperature rolling, and then subjecting the strip to a third cleaning and brushing to obtain a strip of finished size; wherein the total rolling deformation of the second multi-pass room temperature rolling is 30%-80%, and the rolling deformation of each pass is greater than 15%.

[0058] The third purpose of cleaning and brushing is to remove impurities on the surface of the strip and to increase the roughness of the alloy microstructure to facilitate subsequent electroplating of the finished product.

[0059] Step S7, straightening the strip for the first time so that the warping degree of the strip is less than 10 mm / m and the transverse warping height is less than 1 mm.

[0060] Step S8, subjecting the straightened strip to aging treatment under the protection of mixed gas, and then cooling it to below 40° C. before taking it out of the furnace; wherein the aging temperature is 380-480° C., and the holding time is 5-10 hours.

[0061] The improvement of alloy hardness and strength is combined with crystal precipitation. In the range of 380-480℃, the number of cores and proliferation bodies required for crystal precipitation inside low-beryllium copper alloy is significant, which can simultaneously improve the hardness and strength of low-beryllium copper alloy.

[0062] In addition, the aging process requires not only temperature but also time. If the temperature meets the requirements but the time is insufficient, the mechanical properties will not meet the requirements. If the time is too long, the grains of the over-aged material will grow and the performance will deteriorate. Therefore, the aging time of this embodiment is 5-10 hours.

[0063] Step S9, using 600-1000 mesh and 2000-3000 mesh grinding rollers to clean and grind the strip after aging treatment; wherein the grinding speed is 5-30m / min.

[0064] Step S10, the cleaned and ground strip is straightened for the second time and cut into strips to obtain a high-conductivity low-beryllium copper alloy strip for electroplating.

[0065] Preferably, before the first straightening, step S5 and step S6 are repeated, and the strip is subjected to solution treatment and multiple passes of room temperature rolling again to better improve the internal structure of the alloy and further improve the strength, hardness and electrical conductivity of the alloy.

[0066] In some embodiments, in step S1, the preparation process of the low beryllium copper alloy ingot is as follows:

[0067] Electrolytic copper, electrolytic cobalt and electrolytic nickel are added to the smelting furnace in sequence and then evacuated to a vacuum degree of less than 10 -3 After the copper, cobalt and nickel are completely melted, argon is introduced into the smelting furnace to normal pressure. Beryllium copper master alloy, copper-zirconium master alloy and silver powder are added in sequence under the protective atmosphere of argon, and then vacuum is pumped again until the vacuum degree is less than 10 -3 After Pa, vacuum melting is continued. After all the raw materials are melted, the alloy melt is magnetically stirred while maintaining the melting temperature unchanged. Then, it is allowed to stand and be kept warm for 0.5-1h. Argon is introduced again to normal pressure. Under the argon protective atmosphere, the alloy melt is cast into an electromagnetically stirred crystallizer. After cooling, a low-beryllium copper alloy ingot is obtained.

[0068] Among them, the melting temperature is 1200-1300℃, the casting temperature is 1160-1220℃, the casting speed is 35-50mm / min, the cooling water temperature for cooling the crystallizer is less than 30℃, and the cooling water flow rate is 40-50m 3 / h.

[0069] In this embodiment, a static process after magnetic stirring is added to the preparation process of the low-beryllium copper alloy ingot, and the static time is used to make the oxide slag and slag in the alloy melt float up to reduce the defects of the ingot.

[0070] The crystallizer of this embodiment has an electromagnetic stirring function, and electromagnetic stirring is used during the casting process to reduce the segregation of low-beryllium copper alloy components. Since the casting is carried out under the cover of argon gas, no new bubbles will be introduced.

[0071] Preferably, the low-beryllium copper alloy ingot obtained by melting and casting is sawn at the head and tail and then loaded into a walking beam heating furnace for homogenization annealing.

[0072] Preferably, the low-beryllium copper alloy ingot is homogenized annealed in a nitrogen atmosphere to prevent the ingot from being oxidized.

[0073] In some embodiments, in step S2, the processing rate of the first pass of the multiple hot rolling is 14-15%, and the processing rate of each subsequent pass is 20-35%, and the total processing rate is 91-93%.

[0074] The cooling water temperature is room temperature during water cooling, and the cooling water flow rate is 10-15m 3 / h.

[0075] In some embodiments, in step S3, the upper and lower surfaces of the strip are milled by 0.5-1.0 mm, the two side edges are milled by 5-10 mm, and the milling speed is less than 4 m / min.

[0076] Specifically, the accuracy of the strip after milling is ±0.05mm in longitudinal thickness tolerance and ±0.03mm in transverse thickness tolerance.

[0077] In some embodiments, the specific process of the first cleaning and brushing, the second cleaning and brushing, or the third cleaning and brushing is as follows:

[0078] After spraying degreasing agent on the surface of the strip, brush it and then rinse it with water. After immersing the washed strip in pickling agent, use brush rollers with different meshes to brush the surface of the strip for pickling. After rinsing it with water again, spray passivation liquid on the surface of the strip and dry and reel it.

[0079] The temperature of the degreasing agent, pickling agent or passivating solution is not lower than 70°C.

[0080] Preferably, the strip is washed with cold water first to remove the degreasing liquid or pickling agent on the surface of the strip, and then washed with hot water to reduce energy consumption. The temperature of the hot water is not less than 70°C.

[0081] In some embodiments, the degreasing agent is a sodium carbonate aqueous solution with a mass concentration of 1-2%;

[0082] The pickling agent is a mixed solution of sulfuric acid, hydrogen peroxide and deionized water in a volume ratio of 2:1:(3-4), wherein the mass concentration of the sulfuric acid is 98% and the mass concentration of the hydrogen peroxide is 30%;

[0083] The passivation solution is an aqueous solution of benzotriazole with a mass concentration of 0.2-0.5%.

[0084] In some embodiments, the brush roller is a diamond brush roller with a mesh size of 240 mesh, 500 mesh or 800 mesh.

[0085] Specifically, the brush rollers used for the first cleaning and brushing are 240 mesh + 500 mesh + 800 mesh diamond brush rollers, and the brush rollers used for the third cleaning and brushing are + 500 mesh + 800 mesh diamond brush rollers.

[0086] In some embodiments, the mixed gas includes hydrogen and nitrogen to avoid oxidation of the strip;

[0087] Among them, hydrogen accounts for 70-73% of the volume of the mixed gas.

[0088] Hydrogen has better thermal conductivity than hydrogen and nitrogen, and 100% hydrogen has stronger decarburization ability than hydrogen and nitrogen. Using hydrogen as a protective gas will result in less carbon slag on the surface of the strip and more uniform mechanical properties. However, full hydrogen is more dangerous during use, so a certain amount of nitrogen is added in this embodiment.

[0089] In some embodiments, the cleaning grinding is different from the cleaning brush grinding in that the grinding roller is a non-woven polishing roller.

[0090] Example 1

[0091] The alloy of this embodiment is smelted using the following raw materials: electrolytic copper, electrolytic cobalt, electrolytic nickel, beryllium copper master alloy, copper-zirconium master alloy, and silver powder. The composition of the alloy is shown in Example 1 in Table 1.

[0092] 1. Melting and casting: Add electrolytic copper, electrolytic cobalt and electrolytic nickel into the melting furnace in order according to the proportion of each raw material of the alloy, and then evacuate the furnace until the vacuum degree is less than 10 -3 After the copper, cobalt and nickel are completely melted, argon is introduced into the smelting furnace to normal pressure. Beryllium copper master alloy, copper-zirconium master alloy and silver powder are added in sequence under the protective atmosphere of argon, and then vacuum is pumped again until the vacuum degree is less than 10 -3 Pa, vacuum smelting is continued, and after all the raw materials are melted, the alloy melt is magnetically stirred while maintaining the smelting temperature unchanged, and then it is allowed to stand and be kept warm for 0.5-1h, and argon is introduced again to normal pressure, and the alloy melt is cast into an electromagnetically stirred crystallizer under an argon protective atmosphere, and a low-beryllium copper alloy ingot is obtained after cooling; wherein the smelting temperature is 1280°C, the casting temperature is 1220°C, the casting speed is 35-50mm / min, the cooling water temperature for cooling the crystallizer is less than 30°C, and the cooling water flow rate is 40-50m 3 / h.

[0093] 2. Homogenization annealing: After sawing the head and tail of the low beryllium copper alloy ingot, put it into a walking beam heating furnace for homogenization annealing; wherein, the temperature of the heating zone is 920°C, the temperature of the holding zone is 900°C, and the holding time is 10 hours.

[0094] 3. Hot rolling: The ingot after homogenization annealing is rolled for 7 times, the first processing rate is 14-15%, and the processing rate of each subsequent pass is 20-35%, the total rolling processing rate is 93%, and the final rolling temperature is 760℃. After rolling, the strip is water-cooled on the hot rolling mill roller to obtain the strip. The cooling water temperature is room temperature and the cooling water flow rate is 10-15m 3 / h.

[0095] 4. Milling: Mill the strip blank, mill 1mm on the upper and lower surfaces, and 8mm on both sides, with a milling speed of less than 4m / min.

[0096] 5. Rough rolling: The milled strip is subjected to the first multi-pass room temperature rolling, with a total rolling deformation of 92%.

[0097] 6. First cleaning and brushing: After the first multi-pass room temperature rolling, the cracked edges of the strip are cut off, and the surface is cleaned and brushed for the first time. 240 mesh + 500 mesh + 800 mesh brush rollers are used to remove impurities on the surface of the strip.

[0098] 7. Solution treatment: The strip is solution treated in a vertical continuous quenching furnace under the protection of a mixed gas of hydrogen (accounting for 70-73%) and nitrogen, and then the strip is gas cooled; the solution temperature is 930°C, and the strip passes through the continuous quenching furnace at a speed of 10m / min;

[0099] 8. Second cleaning and brushing: After solution treatment, the strip is put into a 500 mesh + 800 mesh brush for a second cleaning and brushing to remove impurities on the strip surface;

[0100] 9. Finishing rolling: The strip is subjected to a second multi-pass room temperature rolling, wherein the total rolling deformation is 60% and the rolling deformation of each pass is greater than 15%.

[0101] 10. Third cleaning and brushing: Put the strip after the second multi-pass room temperature rolling into a 500 mesh + 800 mesh brush for the third cleaning and brushing to remove impurities on the strip surface.

[0102] 11. First straightening: Use a straightening machine to straighten the strip after the third cleaning and brushing so that the warping degree of the strip is less than 10mm / m and the lateral warping height is less than 1mm.

[0103] 12. Aging: Put the strip after the first straightening into a bell-type aging furnace, and heat it to 480℃ for 6 hours in a protective atmosphere of a mixed gas of hydrogen (accounting for 70-73%) and nitrogen, and then cool it to below 40℃ and take it out of the furnace.

[0104] 13. Cleaning and grinding: Use 800 mesh + 2000 mesh grinding rollers to clean and grind the surface of the aged beryllium copper strip, and the grinding speed is maintained at 15m / min.

[0105] 14. Second straightening: The cleaned and ground strip is straightened for the second time and cut into strips to obtain a high-conductivity, low-beryllium copper alloy strip for electroplating.

[0106] The temperature of the hot water, degreasing agent, pickling agent or passivation solution used in the first cleaning and brushing, the second cleaning and brushing, the third cleaning and brushing or cleaning and grinding described in this embodiment is not less than 70° C. The degreasing agent is a sodium carbonate aqueous solution with a mass concentration of 1.5%; the pickling agent is a mixed solution of sulfuric acid, hydrogen peroxide and deionized water in a volume ratio of 2:1:3, wherein the mass concentration of the sulfuric acid is 98% and the mass concentration of the hydrogen peroxide is 30%; the passivation solution is an aqueous solution of benzotriazole with a mass concentration of 0.3%.

[0107] The properties of the strip obtained in this example are shown in Example 1 in Table 2.

[0108] Example 2

[0109] The alloy of this embodiment is smelted using the following raw materials: electrolytic copper, electrolytic cobalt, electrolytic nickel, beryllium copper master alloy, copper-zirconium master alloy, and silver powder. The composition of the alloy is shown in Example 2 of Table 1.

[0110] 1. Melting and casting: Add electrolytic copper, electrolytic cobalt and electrolytic nickel into the melting furnace in order according to the proportion of each raw material of the alloy, and then evacuate the furnace until the vacuum degree is less than 10 -3 After the copper, cobalt and nickel are completely melted, argon is introduced into the smelting furnace to normal pressure. Beryllium copper master alloy, copper-zirconium master alloy and silver powder are added in sequence under the protective atmosphere of argon, and then vacuum is pumped again until the vacuum degree is less than 10 -3 Pa, vacuum smelting is continued, and after all the raw materials are melted, the alloy melt is magnetically stirred while maintaining the smelting temperature unchanged, and then it is allowed to stand and be kept warm for 0.5-1h, and argon is introduced again to normal pressure, and the alloy melt is cast into an electromagnetically stirred crystallizer under an argon protective atmosphere, and a low-beryllium copper alloy ingot is obtained after cooling; wherein the smelting temperature is 1250°C, the casting temperature is 1180°C, the casting speed is 35-50mm / min, the cooling water temperature for cooling the crystallizer is less than 30°C, and the cooling water flow rate is 40-50m 3 / h.

[0111] 2. Homogenization annealing: After sawing the head and tail of the low beryllium copper alloy ingot, put it into a walking beam heating furnace for homogenization annealing; the temperature of the heating zone is 940°C, the temperature of the holding zone is 920°C, and the holding time is 8 hours.

[0112] 3. Hot rolling: The ingot after homogenization annealing is rolled for 7 times, the first processing rate is 14-15%, and the processing rate of each subsequent pass is 20-35%, the total rolling processing rate is 92%, and the final rolling temperature is 780℃. After rolling, the strip is water-cooled on the hot rolling mill roller to obtain the strip. The cooling water temperature is room temperature during water cooling, and the cooling water flow rate is 10-15m 3 / h.

[0113] 4. Milling: Mill the strip blank, with 0.7mm milling on the upper and lower surfaces and 8mm milling on both sides, and the milling speed is less than 4m / min.

[0114] 5. Rough rolling: The milled strip is subjected to the first multi-pass room temperature rolling, with a total rolling deformation of 92%.

[0115] 6. First cleaning and brushing: After the first multi-pass room temperature rolling, the cracked edges of the strip are cut off, and the surface is cleaned and brushed for the first time. 240 mesh + 500 mesh + 800 mesh brush rollers are used to remove impurities on the surface of the strip.

[0116] 7. Solution treatment: The strip is solution treated in a vertical continuous quenching furnace under the protection of a mixed gas of hydrogen (accounting for 70-73%) and nitrogen, and then the strip is gas cooled; the solution temperature is 950°C, and the strip passes through the continuous quenching furnace at a speed of 35m / min;

[0117] 8. Second cleaning and brushing: After solution treatment, the strip is put into a 500 mesh + 800 mesh brush for a second cleaning and brushing to remove impurities on the strip surface;

[0118] 9. Finishing rolling: The strip is subjected to a second multi-pass room temperature rolling, wherein the total rolling deformation is 55% and the rolling deformation of each pass is greater than 15%.

[0119] 10. Third cleaning and brushing: Put the strip after the second multi-pass room temperature rolling into a 500 mesh + 800 mesh brush for the third cleaning and brushing to remove impurities on the strip surface.

[0120] 11. First straightening: Use a straightening machine to straighten the strip after the third cleaning and brushing so that the warping degree of the strip is less than 10mm / m and the lateral warping height is less than 1mm.

[0121] 12. Aging: Put the strip after the first straightening into a bell-type aging furnace, and heat it to 460℃ for 8h in a protective atmosphere of a mixed gas of hydrogen (accounting for 70-73%) and nitrogen, and then cool it to below 40℃ and take it out of the furnace.

[0122] 13. Cleaning and grinding: Use 800 mesh + 2000 mesh grinding rollers to clean and grind the surface of the aged beryllium copper strip, and the grinding speed is maintained at 30m / min.

[0123] 14. Second straightening: The cleaned and ground strip is straightened for the second time and cut into strips to obtain a high-conductivity, low-beryllium copper alloy strip for electroplating.

[0124] The temperature of the hot water, degreasing agent, pickling agent or passivation solution used in the first cleaning and brushing, the second cleaning and brushing, the third cleaning and brushing or cleaning and grinding described in this embodiment is not less than 70° C. The degreasing agent is a sodium carbonate aqueous solution with a mass concentration of 1.0%; the pickling agent is a mixed solution of sulfuric acid, hydrogen peroxide and deionized water in a volume ratio of 2:1:3, wherein the mass concentration of the sulfuric acid is 98% and the mass concentration of the hydrogen peroxide is 30%; the passivation solution is an aqueous solution of benzotriazole with a mass concentration of 0.2%.

[0125] The properties of the strip obtained in this example are shown in Example 2 in Table 2.

[0126] Example 3

[0127] The alloy of this embodiment is smelted using the following raw materials: electrolytic copper, electrolytic cobalt, electrolytic nickel, beryllium copper master alloy, copper-zirconium master alloy, and silver powder. The composition of the alloy is shown in Example 3 of Table 1.

[0128] 1. Melting and casting: Add electrolytic copper, electrolytic cobalt and electrolytic nickel into the melting furnace in order according to the proportion of each raw material of the alloy, and then evacuate the furnace until the vacuum degree is less than 10 -3 After the copper, cobalt and nickel are completely melted, argon is introduced into the smelting furnace to normal pressure. Beryllium copper master alloy, copper-zirconium master alloy and silver powder are added in sequence under the protective atmosphere of argon, and then vacuum is pumped again until the vacuum degree is less than 10 -3 Pa, vacuum smelting is continued, and after all the raw materials are melted, the alloy melt is magnetically stirred while maintaining the smelting temperature unchanged, and then it is allowed to stand and be kept warm for 0.5-1h, and argon is introduced again to normal pressure, and the alloy melt is cast into an electromagnetically stirred crystallizer under an argon protective atmosphere, and a low-beryllium copper alloy ingot is obtained after cooling; wherein the smelting temperature is 1230°C, the casting temperature is 1160°C, the casting speed is 35-50mm / min, the cooling water temperature for cooling the crystallizer is less than 30°C, and the cooling water flow rate is 40-50m 3 / h.

[0129] 2. Homogenization annealing: After sawing the head and tail of the low beryllium copper alloy ingot, put it into a walking beam heating furnace for homogenization annealing; the temperature of the heating zone is 970°C, the temperature of the holding zone is 950°C, and the holding time is 6 hours.

[0130] 3. Hot rolling: The ingot after homogenization annealing is rolled for 7 times, the first processing rate is 14-15%, and the processing rate of each subsequent pass is 20-35%, the total rolling processing rate is 93%, and the final rolling temperature is 800℃. After rolling, the strip is water-cooled on the hot rolling mill roller to obtain the strip. The cooling water temperature is room temperature during water cooling, and the cooling water flow rate is 10-15m 3 / h.

[0131] 4. Milling: Mill the strip blank, with 0.6mm milling on the upper and lower surfaces and 10mm milling on both sides. The milling speed is less than 4m / min.

[0132] 5. Rough rolling: The milled strip is subjected to the first multi-pass room temperature rolling, with a total rolling deformation of 92%.

[0133] 6. First cleaning and brushing: After the first multi-pass room temperature rolling, the cracked edges of the strip are cut off, and the surface is cleaned and brushed for the first time. 240 mesh + 500 mesh + 800 mesh brush rollers are used to remove impurities on the surface of the strip.

[0134] 7. Solution treatment: The strip is solution treated in a vertical continuous quenching furnace under the protection of a mixed gas of hydrogen (accounting for 70-73%) and nitrogen, and then the strip is gas cooled; the solution temperature is 940°C, and the strip passes through the continuous quenching furnace at a speed of 25m / min;

[0135] 8. Second cleaning and brushing: After solution treatment, the strip is put into a 500 mesh + 800 mesh brush for a second cleaning and brushing to remove impurities on the strip surface;

[0136] 9. Finishing rolling: The strip is subjected to a second multi-pass room temperature rolling, wherein the total rolling deformation is 35% and the rolling deformation of each pass is greater than 15%.

[0137] 10. Third cleaning and brushing: Put the strip after the second multi-pass room temperature rolling into a 500 mesh + 800 mesh brush for the third cleaning and brushing to remove impurities on the strip surface.

[0138] 11. First straightening: Use a straightening machine to straighten the strip after the third cleaning and brushing so that the warping degree of the strip is less than 10mm / m and the lateral warping height is less than 1mm.

[0139] 12. Aging: Put the strip after the first straightening into a bell-type aging furnace, and heat it to 380℃ for 8h in a protective atmosphere of a mixed gas of hydrogen (accounting for 70-73%) and nitrogen, and then cool it to below 40℃ and take it out of the furnace.

[0140] 13. Cleaning and grinding: Use 800 mesh + 2000 mesh grinding rollers to clean and grind the surface of the aged beryllium copper strip, and the grinding speed is maintained at 30m / min.

[0141] 14. Second straightening: The cleaned and ground strip is straightened for the second time and cut into strips to obtain a high-conductivity, low-beryllium copper alloy strip for electroplating.

[0142] The temperature of the hot water, degreasing agent, pickling agent or passivation solution used in the first cleaning and brushing, the second cleaning and brushing, the third cleaning and brushing or cleaning and grinding described in this embodiment is not less than 70° C. The degreasing agent is a sodium carbonate aqueous solution with a mass concentration of 2.0%; the pickling agent is a mixed solution of sulfuric acid, hydrogen peroxide and deionized water with a volume ratio of 2:1:4, wherein the mass concentration of the sulfuric acid is 98% and the mass concentration of the hydrogen peroxide is 30%; the passivation solution is an aqueous solution of benzotriazole with a mass concentration of 0.5%.

[0143] The properties of the strip obtained in this example are shown in Example 3 in Table 2.

[0144] Example 4

[0145] The alloy of this embodiment is smelted using the following raw materials: electrolytic copper, electrolytic cobalt, electrolytic nickel, beryllium copper master alloy, copper-zirconium master alloy, and silver powder. The composition of the alloy is shown in Example 4 in Table 1.

[0146] 1. Melting and casting: Add electrolytic copper, electrolytic cobalt and electrolytic nickel into the melting furnace in order according to the proportion of each raw material of the alloy, and then evacuate the furnace until the vacuum degree is less than 10 -3 After the copper, cobalt and nickel are completely melted, argon is introduced into the smelting furnace to normal pressure. Beryllium copper master alloy, copper-zirconium master alloy and silver powder are added in sequence under the protective atmosphere of argon, and then vacuum is pumped again until the vacuum degree is less than 10 -3 After Pa, vacuum smelting is continued. After all the raw materials are melted, the alloy melt is magnetically stirred while maintaining the smelting temperature unchanged, and then it is allowed to stand and be kept warm for 0.5-1h. Argon is introduced again to normal pressure, and the alloy melt is cast into an electromagnetically stirred crystallizer under an argon protective atmosphere. After cooling, a low-beryllium copper alloy ingot is obtained; wherein the smelting temperature is 1300°C, the casting temperature is 1220°C, the casting speed is 35-50mm / min, the cooling water temperature for cooling the crystallizer is less than 30°C, and the cooling water flow rate is 40-50m 3 / h.

[0147] 2. Homogenization annealing: After sawing the head and tail of the low beryllium copper alloy ingot, put it into a walking beam heating furnace for homogenization annealing; the temperature of the heating zone is 920°C, the temperature of the holding zone is 900°C, and the holding time is 8 hours.

[0148] 3. Hot rolling: The ingot after homogenization annealing is rolled for 7 times, the first processing rate is 14-15%, and the processing rate of each subsequent pass is 20-35%, the total rolling processing rate is 92%, and the final rolling temperature is 780℃. After rolling, the strip is water-cooled on the hot rolling mill roller to obtain the strip. The cooling water temperature is room temperature during water cooling, and the cooling water flow rate is 10-15m 3 / h.

[0149] 4. Milling: Mill the strip blank, with 0.9mm milling on the upper and lower surfaces and 8mm milling on both sides, and the milling speed is less than 4m / min.

[0150] 5. Rough rolling: The milled strip is subjected to the first multi-pass room temperature rolling, and the total rolling deformation is 91%.

[0151] 6. First cleaning and brushing: After the first multi-pass room temperature rolling, the cracked edges of the strip are cut off, and the surface is cleaned and brushed for the first time. 240 mesh + 500 mesh + 800 mesh brush rollers are used to remove impurities on the surface of the strip.

[0152] 7. Solution treatment: The strip is solution treated in a vertical continuous quenching furnace under the protection of a mixed gas of hydrogen (accounting for 70-73%) and nitrogen, and then the strip is gas cooled; the solution temperature is 950°C, and the strip passes through the continuous quenching furnace at a speed of 10m / min;

[0153] 8. Second cleaning and brushing: After solution treatment, the strip is put into a 500 mesh + 800 mesh brush for a second cleaning and brushing to remove impurities on the strip surface;

[0154] 9. Finishing rolling: The strip is subjected to a second multi-pass room temperature rolling, wherein the total rolling deformation is 30% and the rolling deformation of each pass is greater than 15%.

[0155] 10. Third cleaning and brushing: Put the strip after the second multi-pass room temperature rolling into a 500 mesh + 800 mesh brush for the third cleaning and brushing to remove impurities on the strip surface.

[0156] 11. First straightening: Use a straightening machine to straighten the strip after the third cleaning and brushing so that the warping degree of the strip is less than 10mm / m and the lateral warping height is less than 1mm.

[0157] 12. Aging: Put the strip after the first straightening into a bell-type aging furnace, and heat it to 400℃ for 7h in a protective atmosphere of a mixed gas of hydrogen (accounting for 70-73%) and nitrogen, and then cool it to below 40℃ and take it out of the furnace.

[0158] 13. Cleaning and grinding: Use 800 mesh + 2000 mesh grinding rollers to clean and grind the surface of the aged beryllium copper strip, and the grinding speed is maintained at 25m / min.

[0159] 14. Second straightening: The cleaned and ground strip is straightened for the second time and cut into strips to obtain a high-conductivity, low-beryllium copper alloy strip for electroplating.

[0160] The temperature of the hot water, degreasing agent, pickling agent or passivation solution used in the first cleaning and brushing, the second cleaning and brushing, the third cleaning and brushing or cleaning and grinding described in this embodiment is not less than 70° C. The degreasing agent is a sodium carbonate aqueous solution with a mass concentration of 1.8%; the pickling agent is a mixed solution of sulfuric acid, hydrogen peroxide and deionized water with a volume ratio of 2:1:4, wherein the mass concentration of the sulfuric acid is 98% and the mass concentration of the hydrogen peroxide is 30%; the passivation solution is an aqueous solution of benzotriazole with a mass concentration of 0.4%.

[0161] The properties of the strip obtained in this example are shown in Example 4 in Table 2.

[0162] Table 1 Alloy composition formula of Examples 1-4 (wt%)

[0163]

[0164] Table 2 Alloy properties of Examples 1-4

[0165]

[0166]

[0167] As can be seen from Table 2, the high-conductivity low-beryllium copper alloy strip for electroplating prepared in Examples 1-4 has a tensile strength of 750-9500 MPa and a conductivity of 50-60% IACS. It is a conductive elastic material with high elasticity, high strength and excellent stress relaxation resistance, and can be widely used in telecommunications, electronics industry, automotive electronic components, etc.

[0168] In summary, the solution proposed by the present invention has the following technical effects:

[0169] The product of the invention improves the conductivity of the beryllium copper alloy strip by reducing the beryllium content and increasing the silver content.

[0170] In addition, the preparation method of the present invention increases the surface roughness of the strip by adding multiple room temperature rolling and multiple cleaning, brushing and grinding processes after homogenization annealing and hot rolling, so that the coating of the strip after electroplating is more uniform.

[0171] In addition, the low-beryllium copper alloy of the present invention has a tensile strength of 750-950 MPa, a conductivity of 50-60% IACS, an elongation of 10-15%, and a simple preparation process, thereby realizing mass production.

[0172] Please note that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. The above embodiments only express several implementation methods of the present application, and their descriptions are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all belong to the scope of protection of the present application. Therefore, the scope of protection of the patent in this application shall be based on the attached claims.

Claims

1. A high-conductivity low-beryllium copper alloy strip for electroplating, characterized in that: Calculated by mass percentage, it includes Be: 0.2%-0.4%, Co: 0.4%-0.6%, Ni: 0.05%-0.2%, Ag: 0.1-0.3%, Zr: 0.05%-0.1%, and the balance is Cu.

2. The high-conductivity low-beryllium copper alloy strip for electroplating according to claim 1, characterized in that: Calculated by mass percentage, it includes Be: 0.25%-0.35%, Co: 0.45%-0.55%, Ni: 0.05%-0.15%, Ag: 0.1-0.2%, Zr: 0.05-0.08%, and the balance is Cu.

3. A method for preparing a high-conductivity, low-beryllium copper alloy strip for electroplating according to claim 1 or 2, characterized in that: The preparation method comprises the following steps: Step S1, placing the low-beryllium copper alloy ingot obtained by melting and casting into a walking beam heating furnace for homogenization annealing; wherein the temperature of the insulation zone is 900-950°C, the insulation time is 6-10h, and the temperature of the heating zone is 20°C higher than the temperature of the insulation zone; Step S2, placing the ingot after homogenization annealing on the roller table of a hot rolling mill for multiple hot rolling, and then water cooling on the roller table of the hot rolling mill to obtain a strip; wherein the final rolling temperature is not less than 750° C.; Step S3, milling the upper and lower surfaces and both side edges of the strip blank; Step S4, subjecting the milled strip to a first multi-pass normal temperature rolling, and then cleaning and brushing the strip after cutting off the cracked edge of the strip; wherein the total rolling deformation of the first multi-pass normal temperature rolling is not less than 90%; Step S5, under the protection of mixed gas, the strip blank after the first cleaning and brushing is placed in a continuous quenching furnace for solution treatment, then the strip blank is gas cooled, and then the strip blank is cleaned and brushed for the second time; wherein the solution temperature is 930-950°C, and the speed of the strip blank passing through the continuous quenching furnace is 5-40m / min; Step S6, performing a second multi-pass room temperature rolling on the strip after the second cleaning and brushing, and then performing a third cleaning and brushing on the strip to obtain a strip of finished size; wherein the total rolling deformation of the second multi-pass room temperature rolling is 30%-80%, and the rolling deformation of each pass is greater than 15%; Step S7, straightening the strip for the first time so that the warping degree of the strip is less than 10 mm / m and the transverse warping height is less than 1 mm; Step S8, subjecting the straightened strip to aging treatment under the protection of mixed gas, and then cooling it to below 40°C before taking it out of the furnace; wherein the aging temperature is 380-480°C, and the holding time is 5-10h; Step S9, using 600-1000 mesh and 2000-3000 mesh grinding rollers to clean and grind the strip after aging treatment; wherein the grinding speed is 5-30 m / min; Step S10, the cleaned and ground strip is straightened for the second time and cut into strips to obtain a high-conductivity low-beryllium copper alloy strip for electroplating.

4. The method for preparing a high-conductivity low-beryllium copper alloy strip for electroplating according to claim 3, characterized in that: In step S1, the preparation process of the low-beryllium copper alloy ingot is as follows: Electrolytic copper, electrolytic cobalt and electrolytic nickel are added to the smelting furnace in sequence and then evacuated to a vacuum degree of less than 10 -3 After the copper, cobalt and nickel are completely melted, argon is introduced into the smelting furnace to normal pressure. Beryllium copper master alloy, copper-zirconium master alloy and silver powder are added in sequence under the protective atmosphere of argon, and then vacuum is pumped again until the vacuum degree is less than 10 -3 After Pa, vacuum melting is continued. After all the raw materials are melted, the alloy melt is magnetically stirred while maintaining the melting temperature unchanged. Then, it is allowed to stand and be kept warm for 0.5-1h. Argon is introduced again to normal pressure. Under the protective atmosphere of argon, the alloy melt is cast into an electromagnetically stirred crystallizer. After cooling, a low-beryllium copper alloy ingot is obtained. Among them, the melting temperature is 1200-1300℃, the casting temperature is 1160-1220℃, the casting speed is 35-50mm / min, the cooling water temperature for cooling the crystallizer is less than 30℃, and the cooling water flow rate is 40-50m 3 / h.

5. The method for preparing a high-conductivity low-beryllium copper alloy strip for electroplating according to claim 3, characterized in that: In the step S2, the first pass processing rate of the multiple passes of hot rolling is 14-15%, and the processing rate of each subsequent pass is 20-35%, and the total processing rate is 91-93%; The cooling water temperature is room temperature during water cooling, and the cooling water flow rate is 10-15m 3 / h.

6. The method for preparing a high-conductivity low-beryllium copper alloy strip for electroplating according to claim 3, characterized in that: In step S3, the upper and lower surfaces of the strip are milled by 0.5-1.0 mm, and the two side edges are milled by 5-10 mm, and the milling speed is less than 4 m / min.

7. The method for preparing a high-conductivity low-beryllium copper alloy strip for electroplating according to claim 3, characterized in that: The specific process of the first cleaning and brushing, the second cleaning and brushing or the third cleaning and brushing is as follows: After spraying degreasing agent on the surface of the strip, brush it and then rinse it with water. After immersing the washed strip in pickling agent, use brush rollers with different meshes to brush the surface of the strip for pickling. After rinsing it with water again, spray passivation liquid on the surface of the strip and dry and reel it. The temperature of the degreasing agent, pickling agent or passivating solution is not lower than 70°C.

8. The method for preparing a high-conductivity low-beryllium copper alloy strip for electroplating according to claim 7, characterized in that: The degreasing agent is a sodium carbonate aqueous solution with a mass concentration of 1-2%; The pickling agent is a mixed solution of sulfuric acid, hydrogen peroxide and deionized water in a volume ratio of 2:1:(3-4), wherein the mass concentration of the sulfuric acid is 98% and the mass concentration of the hydrogen peroxide is 30%; The passivation solution is an aqueous solution of benzotriazole with a mass concentration of 0.2-0.5%.

9. The method for preparing a high-conductivity low-beryllium copper alloy strip for electroplating according to claim 7, characterized in that: The brush roller is a diamond brush roller with a mesh number of 240 meshes, 500 meshes or 800 meshes.

10. The method for preparing a high-conductivity low-beryllium copper alloy strip for electroplating according to claim 3, characterized in that: The mixed gas includes hydrogen and nitrogen; Among them, hydrogen accounts for 70-73% of the volume of the mixed gas.

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