A high-elasticity, environmentally friendly copper alloy ultrathin rolled material for connectors and its preparation method

Abstract

This invention belongs to the field of alloy processing technology, and provides a high-elasticity, environmentally friendly copper alloy ultrathin rolled material for connectors and its preparation method. The ultrathin rolled copper alloy is composed of the following copper alloy, containing the following components by mass percentage: Ni: 3.5%–4.0%, Si: 1.2%–1.3%, Co: 0.45%–0.55%, Cr: 0.45%–0.55%, Ti: 0.1%–0.2%, with the remainder consisting of Cu and unavoidable impurities. The method of this invention involves adding Cr and Ti along with the raw materials into a vacuum degassing furnace for melting, followed by multiple rolling and aging treatments to strengthen the copper alloy. During this melting and casting process, Cr and Ti exhibit their unique characteristics, particularly the dispersed distribution and interaction of Cr precipitates, and the... By refining the microstructure of copper alloys and enriching them on the Cr surface, the elastic strain energy of Cr precipitates can be improved. These advantages can enhance the conductivity, mechanical properties, and elasticity of copper alloys used as connectors and contacts, resulting in superior performance that is more suitable for the operating environment.

Description

Technical Field

[0001] This invention belongs to the field of alloy processing technology, specifically a high-elasticity, environmentally friendly copper alloy ultra-thin rolled material for connectors and its preparation method. Background Technology

[0002] To meet the diverse application needs of new energy vehicles, the key performance indicators of new energy vehicle connectors have become more diversified. Among them, the requirements for copper alloy materials tend to be good voltage and temperature resistance. Conventional automobiles have a rated voltage of 600V, while commercial vehicles and buses can withstand voltages up to 1000V. The current resistance can reach 250,000A depending on the current of the high-voltage system components. The temperature resistance or high temperature resistance level is divided into 125℃, 150℃, and 200℃. It also requires copper alloy materials to have good ultra-high strength and excellent electrical and thermal conductivity. Furthermore, it must maintain excellent stress relaxation resistance under high strength, good weldability and bending performance, good bending formability, and insensitivity to stress corrosion cracking. At the same time, it must meet the requirements of equipment miniaturization, high-speed communication, fast charging, and rapid heat conduction. This also requires higher requirements for the high strength and ultra-thin performance of copper alloy materials.

[0003] In the application of connectors in new energy vehicles, some applications use super tin-phosphorus bronze. This material has excellent processing performance, high strength, and good wear resistance, but its conductivity is significantly low, with a maximum conductivity (IACS%) of around 15%. In other fields, copper-nickel-silicon C7025 series materials are used. This material has excellent bending performance, high strength, and good corrosion resistance, but its conductivity decreases significantly with increasing hardness, and its bending performance deteriorates rapidly. In addition, in some special applications, beryllium bronze has properties that other copper alloys cannot match. Its mechanical properties, namely strength, hardness, wear resistance, and fatigue resistance, are the best among copper alloys. However, it has extremely harsh production conditions, and beryllium dust is extremely harmful to workers, easily causing beryllium lung cancer, and is not considered an environmentally friendly material.

[0004] Therefore, the current market demand is for a copper alloy ultra-thin rolled material that combines high elasticity, high conductivity, and environmental friendliness for connectors. Summary of the Invention

[0005] The technical problem solved by this invention is to provide a high-elasticity, environmentally friendly copper alloy ultra-thin rolled material for connectors and its preparation method, so as to overcome the defects in the above-mentioned technical background.

[0006] The technical problem solved by this invention is achieved by the following technical solution:

[0007] A high-elasticity, environmentally friendly copper alloy ultra-thin rolled material for connectors, wherein the copper alloy ultra-thin rolled material is composed of the following copper alloy, comprising the following components by mass percentage: Ni: 3.5%–4.0%, Si: 1.2%–1.3%, Co: 0.45%–0.55%, Cr: 0.45%–0.55%, Ti: 0.1%–0.2%, with the remainder consisting of Cu and unavoidable impurities.

[0008] This invention enhances the strengthening effect of copper alloys after aging treatment by adding Cr and Ti. After aging treatment, the precipitated Cr particles form a dispersed precipitate phase that is uniformly distributed in the Cu matrix, thereby improving the electrical conductivity of the copper alloy. Furthermore, this precipitate phase interacts with surrounding dislocations, effectively preventing grain boundary and dislocation movement, thus improving the mechanical properties of the copper alloy. Ti can form various compounds with Cu and Ni, such as Ni₂Ti, NiTi, and Cu₄Ti phases. The presence of these phases effectively refines the grain size of the copper alloy, and Ti can accumulate on the Cr surface, increasing the elastic strain energy of the Cr precipitate phase. Therefore, Ti can improve the mechanical properties, electrical conductivity, and high elasticity of the copper alloy, resulting in superior performance more suitable for the operating environment and addressing the conductivity, mechanical properties, and high elasticity defects present when used as connectors and contact pieces.

[0009] A method for preparing a high-elasticity, environmentally friendly copper alloy ultrathin rolled material for connectors, using the aforementioned copper alloy component content as raw material, specifically includes the following steps:

[0010] S1. First, before forging, the ultra-large KGCL-8T vacuum degassing furnace is evacuated to a pressure of 0.01 Pa. Then, argon is introduced as a protective gas, and the pressure inside the vacuum degassing furnace is adjusted to 10-20 Pa. Next, the weighed raw materials are put into the vacuum degassing furnace for melting, and the melting is maintained for 3-8 hours. After melting is completed, casting is carried out using a pull-stop process to obtain the initial casting billet. It is necessary to strictly control the mass percentage values ​​of the raw material components within the specified range.

[0011] S2. The head and tail of the initial billet are cut off by a sawing machine and its surface is inspected. Then the initial billet is subjected to step-by-step continuous annealing and heating, and is rolled into a billet with a thickness of 20mm by a hot rolling mill. Then the 20mm thick billet is milled by a milling machine to obtain a billet with a thickness of 18mm.

[0012] S3. The 18mm thick casting billet is rough rolled to open the billet. It takes 8 rolling passes to get from 18mm to 2.5mm. The rolling process is as follows: 18mm-15.3mm-12mm-9.3mm-7.3mm-5.5mm-4.3mm-3.2mm-2.5mm to get a 2.5mm thick casting billet. Then the casting billet is first trimmed by rough trimming, and then cleaned and ground by thick cleaning line.

[0013] S4. The thickness of the billet is rolled from 2.5mm to 1.0mm using a medium / finishing mill. Then, the 1.0mm thick billet is subjected to high-temperature suspension furnace online solution heat treatment and thick washing and grinding cleaning treatment.

[0014] S5. The 1.0mm thick billet is rolled using an imported six-roll mill. The rolling process from 1.0mm to 0.3mm requires a total of 5 rolling passes. The rolling process is as follows: 1.0mm-0.8mm-0.63mm-0.5mm-0.38mm-0.3mm, to obtain a 0.3mm thick billet. Then, the billet is subjected to thin strip grinding and cleaning, and the billet is trimmed and deburred using a slitting machine. The trimming range on one side is 5-7mm.

[0015] S6. The thickness of the cast billet is rolled from 0.3mm to 0.08mm using a 20-roll finishing mill. A total of 5 rolling passes are required. The rolling process is as follows: 0.3mm-0.23mm-0.18mm-0.14mm-0.11mm-0.08mm, thus obtaining a cast billet with a thickness of 0.08mm. Then, the cast billet is subjected to online solution heat treatment in a high-temperature hanging furnace.

[0016] S7. The casting billet thickness is rolled again from 0.08mm to 0.05mm using a 20-roll precision rolling mill, requiring one rolling pass. The rolling process is as follows: 0.08mm-0.05mm, to obtain a casting billet with a thickness of 0.05mm. Then, the casting billet is degreased and cleaned through a cleaning line. After cleaning, it is aged in a bell furnace. After aging, the casting billet is degreased and cleaned again through a cleaning line. Finally, after bending and straightening and shearing, it is packaged and stored.

[0017] This invention involves sequentially hot-rolling, roughing, intermediate / finishing, imported six-roll rolling, and twenty-roll rolling of a copper alloy billet to obtain a 0.05mm thick copper alloy sheet. Plastic processing of the billet breaks down the coarse dendritic grains in the as-cast state into fine equiaxed grains, thereby increasing the number of grain boundaries to hinder dislocation movement and improve the mechanical properties of the copper alloy. Milling, thick washing, and thin strip cleaning remove oxides, surface defects, and degrease from the billet surface. A grinding brush current is used to improve the billet's conductivity. To accommodate two plastic processing operations at thicknesses of 1.0mm and 0.08mm, the billet undergoes online solution heat treatment in a high-temperature suspended furnace. This softens the copper alloy billet, restores its plasticity, eliminates casting stress, prevents the formation of brittle eutectoid structures, ensures good toughness and plasticity, improves the elasticity of the copper alloy, and further enhances the overall performance of the copper alloy.

[0018] Preferably, the heating power source for the vacuum degassing furnace melting in step S1 is a medium-high frequency induction power source with a heating rate of 58℃ / s and a melting temperature controlled between 1260℃ and 1360℃.

[0019] Preferably, in step S1, when performing the pull-stop process on the molten material, the casting speed is 60m / min-80m / min, the crystallizer vibration frequency is 30-50 times / min, and the crystallizer vibration amplitude is 2-4mm.

[0020] Preferably, in step S2, when milling the casting blank, a total of two milling operations are performed. In the first operation, the top and bottom surfaces are milled by 0.6-0.8 mm each, and the two sides are milled by 1-2 mm each. In the second operation, the top and bottom surfaces are milled by 0.3-0.5 mm each, and the two sides are milled by 1-2 mm each.

[0021] Preferably, in the step heating furnace of step S2, the step heating temperature is between 980℃ and 1000℃, which is 280℃-360℃ lower than the melting temperature, and the temperature is maintained for 8-10 hours.

[0022] Preferably, in step S3, the rolling speed of the roughing mill is 80-120 m / min, and the front and rear tension is controlled at 40-60 kN; in step S5, the rolling speed of the six-roll mill is 150-200 m / min, and the front and rear tension is controlled at 30-50 kN; while in steps S6 and S7, the rolling speed of the twenty-roll finishing mill is 200-300 m / min, and the front and rear tension is controlled at 5-10 kN.

[0023] Preferably, the cleaning speed of the thick-strip grinding cleaning in S4 is 20-30 m / min and the grinding brush current is 0.8-1.2 A, and the cleaning speed of the thin-strip grinding cleaning in S5 is 30-50 m / min and the grinding brush current is 0.6-1.0 A.

[0024] Preferably, the annealing temperature of the hanging furnace in steps S4 and S6 is 980℃-1020℃, the annealing rate in step S4 is 2-4m / min, and the annealing rate in step S6 is 18-20m / min.

[0025] Preferably, the aging temperature of the bell-shaped furnace in S7 is 440℃-460℃, the heating time is 3-5h, and the holding time is 3-5h.

[0026] This invention involves sequentially hot-rolling, roughing, intermediate / finishing, imported six-roll rolling, and twenty-roll rolling of a copper alloy billet to obtain a 0.05mm thick copper alloy sheet. Plastic processing of the billet breaks down the coarse dendritic grains in the as-cast state into fine equiaxed grains, thereby increasing the number of grain boundaries to hinder dislocation movement and improve the mechanical properties of the copper alloy. Milling, thick washing, and thin strip cleaning remove oxides, surface defects, and degrease from the billet surface. A grinding brush current is used to improve the billet's conductivity. To accommodate two plastic processing operations at thicknesses of 1.0mm and 0.08mm, the billet undergoes online solution heat treatment in a high-temperature suspended furnace. This softens the copper alloy billet, restores its plasticity, eliminates casting stress, prevents the formation of brittle eutectoid structures, ensures good toughness and plasticity, improves the elasticity of the copper alloy, and further enhances the overall performance of the copper alloy.

[0027] Compared with the prior art, the present invention has the following beneficial effects: The method of the present invention adds Cr and Ti along with the raw materials into a vacuum degassing furnace for melting, and then obtains a copper alloy through multiple rolling processes. In this process, Cr and Ti play their special roles. The dispersed distribution and interaction of Cr precipitates, as well as Ti's refinement of the copper alloy structure and its own enrichment on the Cr surface, improve the elastic strain energy of Cr precipitates. This improves the conductivity, mechanical properties and high elasticity defects of the copper alloy when used as connectors and contact pieces, and can obtain better performance that is more suitable for the operating environment. Attached Figure Description

[0028] Figure 1 This is a process flow diagram of the casting preparation of ultra-thin rolled copper alloy materials in this invention;

[0029] Figure 2 This is a table of copper alloy performance parameters for each embodiment of the present invention. Detailed Implementation

[0030] The embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention.

[0031] Figure 1 This is a process flow diagram of the copper alloy block used for rolling materials in this invention;

[0032] Example 1:

[0033] In Example 1, this copper alloy comprises raw materials with the following mass ratio components:

[0034] Ni: 3.5%, Si: 1.2%, Co: 0.45%, Cr: 0.45%, Ti: 0.1%, with the remainder consisting of Cu and unavoidable impurities;

[0035] Initial casting production: A medium-high frequency induction power supply was selected as the heating power source for the ultra-large KGCL-8T vacuum degassing furnace, with a heating rate of 58℃ / s. The melting temperature was controlled between 1260℃ and 1310℃. Before forging, the ultra-large KGCL-8T vacuum degassing furnace was evacuated to a pressure of 0.01Pa, and then argon was introduced as a protective gas. The pressure inside the vacuum degassing furnace was adjusted to 10Pa. The weighed raw materials were then added to the vacuum degassing furnace for melting and held for 3 hours. After melting, a pull-stop process was used for casting. The casting speed was 60m / min, the crystallizer vibration frequency was 30 times / min, and the crystallizer vibration amplitude was 2mm. This yielded an initial casting with dimensions of 150*410*6500mm. It was crucial to strictly control the mass percentage values ​​of the raw material components within the specified range.

[0036] Hot rolling: The head and tail of the initial billet are cut off by a sawing machine and its surface is inspected. Then the initial billet is heated by a walking beam continuous annealing heating furnace to 980-900℃ and held for 8 hours. After that, it is hot rolled to a billet with a thickness of 20mm. The billet is then milled twice by a milling machine. The first milling is 0.6mm on the top and bottom and 1mm on each of the two sides. The second milling is 0.3mm on the top and bottom and 1mm on each of the two sides. This process removes surface oxides and surface defects. After milling, a billet with a thickness of 18mm is obtained.

[0037] Rough rolling: The 18mm thick billet is rough rolled at a speed of 80 m / min with a tension of 40 kN. The billet is rolled in 8 passes to obtain a 2.5mm thick billet. The billet is then rough-trimmed to remove small cracks and burrs. After that, it is cleaned and ground in a thick cleaning line to remove residual oxides and other imperfections from the rolled surface. The cleaning speed is 20 m / min and the grinding brush current is 0.8 A.

[0038] Medium / finishing: The thickness of the cast billet is rolled from 2.5mm to 1.0mm using a medium / finishing mill. Then, the 1.0mm thick cast billet is subjected to online solution heat treatment in a high-temperature hanging furnace with an annealing temperature of 980℃-1000℃ and an annealing speed of 2m / min. It is then subjected to thick washing and grinding cleaning treatment with a cleaning speed of 20m / min and a grinding brush current of 0.8A.

[0039] Imported six-roll mill processing: The imported six-roll mill is used to open the 1.0mm thick casting billet. The rolling speed is 150m / min, the front and rear tension is controlled at 30KN, and a total of 5 passes are rolled to obtain a 0.3mm thick casting billet. Then the casting billet is subjected to strip grinding and cleaning at a speed of 30m / min and a grinding brush current of 0.6A. The casting billet is then trimmed and deburred by a slitting machine, with a single-sided trimming range of 5mm.

[0040] Imported 20-roll precision rolling: The casting thickness is rolled from 0.3mm to 0.08mm using a 20-roll precision rolling mill at a rolling speed of 200m / min and a front and rear tension of 5KN, for a total of 5 passes, to obtain a casting thickness of 0.08mm. The casting is then subjected to online solution heat treatment in a high-temperature hanging furnace at an annealing temperature of 980℃-1000℃ and an annealing speed of 2m / min. Subsequently, the casting thickness is rolled again from 0.08mm to 0.05mm using a 20-roll precision rolling mill, for a total of 1 pass, to obtain a casting thickness of 0.05mm.

[0041] Aging process: The casting billet is then degreased, cleaned and passivated through the cleaning line. After cleaning, it is aged in a bell furnace at a temperature of 440-450℃ for 3 hours and a holding time of 3 hours. After aging, the casting billet is degreased, cleaned and passivated again through the cleaning line. Finally, after bending, straightening and shearing, it is packaged and stored.

[0042] like Figure 2 As shown, the copper alloy block prepared by the above method has the following measured parameters: thickness of 0.05 mm, tensile strength of 1050 MPa, yield strength of 960 MPa, elongation of 5%, hardness of 310 HV, conductivity of 45.3 IACS, and bending performance of not breaking when bent 90° along the rolling direction when R / T = 1.

[0043] Implementation 2:

[0044] In Example 2, this copper alloy comprises raw materials with the following mass ratio components:

[0045] Ni: 3.5%, Si: 1.2%, with the remainder consisting of Cu and unavoidable impurities;

[0046] Initial casting production: A medium-high frequency induction power supply was selected as the heating power source for the ultra-large KGCL-8T vacuum degassing furnace, with a heating rate of 58℃ / s. The melting temperature was controlled between 1260℃ and 1310℃. Before forging, the ultra-large KGCL-8T vacuum degassing furnace was evacuated to a pressure of 0.01Pa, and then argon was introduced as a protective gas. The pressure inside the vacuum degassing furnace was adjusted to 10Pa. The weighed raw materials were then added to the vacuum degassing furnace for melting and held for 3 hours. After melting, a pull-stop process was used for casting. The casting speed was 60m / min, the crystallizer vibration frequency was 30 times / min, and the crystallizer vibration amplitude was 2mm. This yielded an initial casting with dimensions of 150*410*6500mm. It was crucial to strictly control the mass percentage values ​​of the raw material components within the specified range.

[0047] Hot rolling: The head and tail of the initial billet are cut off by a sawing machine and its surface is inspected. Then the initial billet is heated by a walking beam continuous annealing heating furnace to 980-900℃ and held for 8 hours. After that, it is hot rolled to a billet with a thickness of 20mm. The billet is then milled twice by a milling machine. The first milling is 0.6mm on the top and bottom and 1mm on each of the two sides. The second milling is 0.3mm on the top and bottom and 1mm on each of the two sides. This process removes surface oxides and surface defects. After milling, a billet with a thickness of 18mm is obtained.

[0048] Rough rolling: The 18mm thick billet is rough rolled at a speed of 80 m / min with a tension of 40 kN. The billet is rolled in 8 passes to obtain a 2.5mm thick billet. The billet is then rough-trimmed to remove small cracks and burrs. After that, it is cleaned and ground in a thick cleaning line to remove residual oxides and other imperfections from the rolled surface. The cleaning speed is 20 m / min and the grinding brush current is 0.8 A.

[0049] Medium / finishing: The thickness of the cast billet is rolled from 2.5mm to 1.0mm using a medium / finishing mill. Then, the 1.0mm thick cast billet is subjected to online solution heat treatment in a high-temperature hanging furnace with an annealing temperature of 980℃-1000℃ and an annealing speed of 2m / min. It is then subjected to thick washing and grinding cleaning treatment with a cleaning speed of 20m / min and a grinding brush current of 0.8A.

[0050] Imported six-roll mill processing: The imported six-roll mill is used to open the 1.0mm thick casting billet. The rolling speed is 150m / min, the front and rear tension is controlled at 30KN, and a total of 5 passes are rolled to obtain a 0.3mm thick casting billet. Then the casting billet is subjected to strip grinding and cleaning at a speed of 30m / min and a grinding brush current of 0.6A. The casting billet is then trimmed and deburred by a slitting machine, with a single-sided trimming range of 5mm.

[0051] Imported 20-roll precision rolling: The casting thickness is rolled from 0.3mm to 0.08mm using a 20-roll precision rolling mill at a rolling speed of 200m / min and a front and rear tension of 5KN, for a total of 5 passes, to obtain a casting thickness of 0.08mm. The casting is then subjected to online solution heat treatment in a high-temperature hanging furnace at an annealing temperature of 980℃-1000℃ and an annealing speed of 2m / min. Subsequently, the casting thickness is rolled again from 0.08mm to 0.05mm using a 20-roll precision rolling mill, for a total of 1 pass, to obtain a casting thickness of 0.05mm.

[0052] Aging process: The casting billet is then degreased, cleaned and passivated through the cleaning line. After cleaning, it is aged in a bell furnace at a temperature of 440-450℃ for 3 hours and a holding time of 3 hours. After aging, the casting billet is degreased, cleaned and passivated again through the cleaning line. Finally, after bending, straightening and shearing, it is packaged and stored.

[0053] like Figure 2 As shown, the copper alloy block prepared by the above method has the following measured parameters: thickness of 0.05 mm, tensile strength of 620 MPa, yield strength of 500 MPa, elongation of 10%, hardness of 180 HV, electrical conductivity of 37 IACS, and bending performance of not breaking when bent 90° along the rolling direction when R / T = 1.

[0054] Example 3:

[0055] In Example 3, this copper alloy comprises raw materials with the following mass ratio components:

[0056] Ni: 3.5%, Si: 1.2%, Co: 0.45%, with the remainder consisting of Cu and unavoidable impurities;

[0057] Initial casting production: A medium-high frequency induction power supply was selected as the heating power source for the ultra-large KGCL-8T vacuum degassing furnace, with a heating rate of 58℃ / s. The melting temperature was controlled between 1260℃ and 1310℃. Before forging, the ultra-large KGCL-8T vacuum degassing furnace was evacuated to a pressure of 0.01Pa, and then argon was introduced as a protective gas. The pressure inside the vacuum degassing furnace was adjusted to 10Pa. The weighed raw materials were then added to the vacuum degassing furnace for melting and held for 3 hours. After melting, a pull-stop process was used for casting. The casting speed was 60m / min, the crystallizer vibration frequency was 30 times / min, and the crystallizer vibration amplitude was 2mm. This yielded an initial casting with dimensions of 150*410*6500mm. It was crucial to strictly control the mass percentage values ​​of the raw material components within the specified range.

[0058] Hot rolling: The head and tail of the initial billet are cut off by a sawing machine and its surface is inspected. Then the initial billet is heated by a walking beam continuous annealing heating furnace to 980-900℃ and held for 8 hours. After that, it is hot rolled to a billet with a thickness of 20mm. The billet is then milled twice by a milling machine. The first milling is 0.6mm on the top and bottom and 1mm on each of the two sides. The second milling is 0.3mm on the top and bottom and 1mm on each of the two sides. This process removes surface oxides and surface defects. After milling, a billet with a thickness of 18mm is obtained.

[0059] Rough rolling: The 18mm thick billet is rough rolled at a speed of 80 m / min with a tension of 40 kN. The billet is rolled in 8 passes to obtain a 2.5mm thick billet. The billet is then rough-trimmed to remove small cracks and burrs. After that, it is cleaned and ground in a thick cleaning line to remove residual oxides and other imperfections from the rolled surface. The cleaning speed is 20 m / min and the grinding brush current is 0.8 A.

[0060] Medium / finishing: The thickness of the cast billet is rolled from 2.5mm to 1.0mm using a medium / finishing mill. Then, the 1.0mm thick cast billet is subjected to online solution heat treatment in a high-temperature hanging furnace with an annealing temperature of 980℃-1000℃ and an annealing speed of 2m / min. It is then subjected to thick washing and grinding cleaning treatment with a cleaning speed of 20m / min and a grinding brush current of 0.8A.

[0061] Imported six-roll mill processing: The imported six-roll mill is used to open the 1.0mm thick casting billet. The rolling speed is 150m / min, the front and rear tension is controlled at 30KN, and a total of 5 passes are rolled to obtain a 0.3mm thick casting billet. Then the casting billet is subjected to strip grinding and cleaning at a speed of 30m / min and a grinding brush current of 0.6A. The casting billet is then trimmed and deburred by a slitting machine, with a single-sided trimming range of 5mm.

[0062] Imported 20-roll precision rolling: The casting thickness is rolled from 0.3mm to 0.08mm using a 20-roll precision rolling mill at a rolling speed of 200m / min and a front and rear tension of 5KN, for a total of 5 passes, to obtain a casting thickness of 0.08mm. The casting is then subjected to online solution heat treatment in a high-temperature hanging furnace at an annealing temperature of 980℃-1000℃ and an annealing speed of 2m / min. Subsequently, the casting thickness is rolled again from 0.08mm to 0.05mm using a 20-roll precision rolling mill, for a total of 1 pass, to obtain a casting thickness of 0.05mm.

[0063] Aging process: The casting billet is then degreased, cleaned and passivated through the cleaning line. After cleaning, it is aged in a bell furnace at a temperature of 440-450℃ for 3 hours and a holding time of 3 hours. After aging, the casting billet is degreased, cleaned and passivated again through the cleaning line. Finally, after bending, straightening and shearing, it is packaged and stored.

[0064] like Figure 2 As shown, the copper alloy block prepared by the above method has the following measured parameters: thickness of 0.05 mm, tensile strength of 1020 MPa, yield strength of 900 MPa, elongation of 5%, hardness of 296 HV, conductivity of 40 IACS, and bending performance of not breaking when bent 90° along the rolling direction when R / T = 1.

[0065] Example 4:

[0066] In Example 4, this copper alloy comprises raw materials with the following mass ratio components:

[0067] Ni: 3.7%, Si: 1.25%, Co: 0.50%, Cr: 0.50%, Ti: 0.15%, with the remainder consisting of Cu and unavoidable impurities;

[0068] Initial casting production: A medium-high frequency induction power supply was selected as the heating power source for the ultra-large KGCL-8T vacuum degassing furnace, with a heating rate of 58℃ / s. The melting temperature was controlled between 1280℃ and 1340℃. Before forging, the ultra-large KGCL-8T vacuum degassing furnace was evacuated to a pressure of 0.01Pa, and then argon was introduced as a protective gas. The pressure inside the vacuum degassing furnace was adjusted to 15Pa. The weighed raw materials were then added to the vacuum degassing furnace for melting and held for 5 hours after melting. After melting, a pull-stop process was used for casting. The casting speed was 70m / min, the crystallizer vibration frequency was 40 times / min, and the crystallizer vibration amplitude was 3mm. This yielded an initial casting with dimensions of 150*410*7000mm. It was crucial to strictly control the mass percentage values ​​of the raw material components within the specified range.

[0069] Hot rolling: The head and tail of the initial billet are cut off by a sawing machine and its surface is inspected. Then the initial billet is heated by a walking beam continuous annealing heating furnace to 990℃-1000℃ and held for 9 hours. After that, it is hot rolled to a billet with a thickness of 20mm. The billet is then milled twice by a milling machine. The first milling is 0.7mm on the top and bottom and 1.5mm on each of the two sides. The second milling is 0.4mm on the top and bottom and 1.5mm on each of the two sides. This process removes surface oxides and surface defects. After milling, a billet with a thickness of 18mm is obtained.

[0070] Rough rolling: The 18mm thick billet is rough rolled at a speed of 100m / min with a tension of 50KN. The billet is rolled in 8 passes to obtain a 2.5mm thick billet. The billet is then rough-trimmed to remove small cracks and burrs. After that, it is cleaned and ground in a thick cleaning line to remove residual oxides and other imperfections from the rolled surface. The cleaning speed is 25m / min and the grinding brush current is 1.0A.

[0071] Medium / finishing: The thickness of the cast billet is rolled from 2.5mm to 1.0mm using a medium / finishing mill. Then, the 1.0mm thick cast billet is subjected to online solution heat treatment in a high-temperature hanging furnace with an annealing temperature of 990℃-1000℃ and an annealing speed of 3m / min. It is then subjected to thick washing and grinding cleaning treatment with a cleaning speed of 25m / min and a grinding brush current of 1.0A.

[0072] Imported six-roll mill processing: The imported six-roll mill is used to open the 1.0mm thick casting billet. The rolling speed is 170m / min, the front and rear tension is controlled at 40KN, and a total of 5 passes are rolled to obtain a 0.3mm thick casting billet. Then the casting billet is subjected to thin strip grinding and cleaning at a speed of 25m / min and a grinding brush current of 1.0A. The casting billet is then trimmed and deburred by a slitting machine. The trimming range on one side is 5-7mm.

[0073] Imported 20-roll precision rolling: The casting thickness is rolled from 0.3mm to 0.08mm using a 20-roll precision rolling mill at a rolling speed of 250m / min and a tension of 8KN, for a total of 5 passes, to obtain a casting thickness of 0.08mm. The casting is then subjected to online solution heat treatment in a high-temperature hanging furnace at an annealing temperature of 990℃-1000℃ and an annealing speed of 3m / min. Subsequently, the casting thickness is rolled again from 0.08mm to 0.05mm using a 20-roll precision rolling mill, for a total of 1 pass, to obtain a casting thickness of 0.05mm.

[0074] Aging process: The casting billet is then degreased, cleaned and passivated through the cleaning line. After cleaning, it is aged in a bell furnace at a temperature of 450℃-460℃ for 4 hours and a holding time of 4 hours. After aging, the casting billet is degreased, cleaned and passivated again through the cleaning line. Finally, after bending, straightening and shearing, it is packaged and stored.

[0075] like Figure 2 As shown, the copper alloy block prepared by the above method has the following measured parameters: thickness of 0.05 mm, tensile strength of 1060 MPa, yield strength of 980 MPa, elongation of 6%, hardness of 300 HV, conductivity of 46.1 IACS, and bending performance of not breaking when bent 90° along the rolling direction when R / T = 1.

[0076] Example 5

[0077] In Example 5, this copper alloy comprises raw materials with the following mass ratio components:

[0078] Ni: 4.0%, Si: 1.3%, Co: 0.55%, Cr: 0.55%, Ti: 0.2%, with the remainder consisting of Cu and unavoidable impurities;

[0079] Initial casting production: A medium-high frequency induction power supply was selected as the heating power source for the ultra-large KGCL-8T vacuum degassing furnace, with a heating rate of 58℃ / s. The melting temperature was controlled between 1300℃ and 1360℃. Before forging, the ultra-large KGCL-8T vacuum degassing furnace was evacuated to a pressure of 0.01Pa, and then argon was introduced as a protective gas. The pressure inside the vacuum degassing furnace was adjusted to 20Pa. The weighed raw materials were then added to the vacuum degassing furnace for melting and held for 8 hours. After melting, a pull-stop process was used for casting. The casting speed was 80m / min, the crystallizer vibration frequency was 50 times / min, and the crystallizer vibration amplitude was 4mm. This yielded an initial casting with dimensions of 150*410*7500mm. It was crucial to strictly control the mass percentage values ​​of the raw material components within the specified range.

[0080] Hot rolling: The head and tail of the initial billet are cut off by a sawing machine and its surface is inspected. Then the initial billet is heated by a walking beam continuous annealing heating furnace to 990℃-1000℃ and held for 10 hours. After that, it is hot rolled to a billet with a thickness of 20mm. The billet is then milled twice by a milling machine. The first milling is 0.8mm on the top and bottom and 2mm on each of the two sides. The second milling is 0.5mm on the top and bottom and 2mm on each of the two sides. This process removes surface oxides and surface defects. After milling, a billet with a thickness of 18mm is obtained.

[0081] Rough rolling: The 18mm thick billet is rough rolled at a speed of 120m / min with a tension of 60KN. The billet is rolled in 8 passes to obtain a 2.5mm thick billet. The billet is then rough-trimmed to remove small cracks and burrs. After that, it is cleaned and ground in a thick cleaning line. The thick cleaning line is used to clean the residual oxides on the surface of the billet. The cleaning speed is 30m / min and the grinding brush current is 1.2A.

[0082] Medium / finishing: The thickness of the cast billet is rolled from 2.5mm to 1.0mm using a medium / finishing mill. Then, the 1.0mm thick cast billet is subjected to online solution heat treatment in a high-temperature hanging furnace with an annealing temperature of 1000℃-1020℃ and an annealing speed of 4m / min. After that, it is subjected to thick washing and grinding cleaning treatment with a cleaning speed of 30m / min and a grinding brush current of 1.2A.

[0083] Imported six-roll mill processing: The imported six-roll mill is used to open the 1.0mm thick casting billet. The rolling speed is 200m / min, the front and rear tension is controlled at 50KN, and a total of 5 passes are rolled to obtain a 0.3mm thick casting billet. Then the casting billet is subjected to strip grinding and cleaning at a speed of 50m / min and a grinding brush current of 1.0A. The casting billet is then trimmed and deburred by a slitting machine, with a single-sided trimming range of 7mm.

[0084] Imported 20-roll precision rolling: The casting thickness is rolled from 0.3mm to 0.08mm using a 20-roll precision rolling mill at a rolling speed of 300m / min and a front and rear tension of 10KN, for a total of 5 passes, to obtain a casting thickness of 0.08mm. The casting is then subjected to online solution heat treatment in a high-temperature hanging furnace at an annealing temperature of 1000℃-1020℃ and an annealing speed of 4m / min. Subsequently, the casting thickness is rolled again from 0.08mm to 0.05mm using a 20-roll precision rolling mill, for a total of 1 pass, to obtain a casting thickness of 0.05mm.

[0085] Aging process: The casting billet is then degreased, cleaned and passivated through the cleaning line. After cleaning, it is aged in a bell furnace at a temperature of 450℃-460℃ for 5 hours and a holding time of 5 hours. After aging, the casting billet is degreased, cleaned and passivated again through the cleaning line. Finally, after bending, straightening and shearing, it is packaged and stored.

[0086] like Figure 2 As shown, the copper alloy block prepared by the above method has the following measured parameters: thickness of 0.05 mm, tensile strength of 1070 MPa, yield strength of 1000 MPa, elongation of 6%, hardness of 350 HV, conductivity of 46.6 IACS, and bending performance of not breaking when bent 90° along the rolling direction when R / T = 1.

[0087] like Figure 2As shown, based on the above performance parameters, under the same processing environment, Example 2 lacks Co, Cr, and Ti elements in its raw material composition compared to Example 1, and Example 3 lacks Cr and Ti elements in its raw material composition compared to Example 1. The performance parameters of Examples 1, 2, and 3 demonstrate the promoting effect of Cr and Ti elements on the performance of the copper alloy block. It can be concluded that the copper alloy block produced by this invention has higher strength than Cu-Ni-Si and higher conductivity than Cu-Ni-Si-Co. Furthermore, compared to the performance parameters of existing tin-phosphorus bronze (QSn6.5-0.1), copper-nickel-silicon (Cu-Ni-Si), and beryllium bronze, the copper alloy block produced by this invention is a product with excellent overall performance, combining high elasticity, environmental friendliness, and high conductivity. The raw material composition content of Examples 4 and 5 was randomly selected from within a specified mass ratio range to verify the accuracy of the performance parameters in Example 1 and reduce the randomness of the data.

[0088] The embodiments of the present invention are given for the purposes of illustration and description. Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a high-elasticity, environmentally friendly copper alloy ultrathin rolled material for connectors, characterized in that, The copper alloy ultrathin rolled material is composed of the following copper alloy, which contains the following components by mass percentage: Ni: 3.5%~4.0%, Si: 1.2%~1.3%, Co: 0.45%~0.55%, Cr: 0.45%~0.55%, Ti: 0.1%~0.2%, with the remainder consisting of Cu and unavoidable impurities. The preparation method of the ultra-thin rolled copper alloy material for high-elasticity and environmentally friendly connectors specifically includes the following steps: S1. First, before forging, the ultra-large KGCL-8T vacuum degassing furnace is evacuated to a pressure of 0.01 Pa. Then, argon is introduced as a protective gas, and the pressure inside the vacuum degassing furnace is adjusted to 10-20 Pa. Next, the weighed raw materials are put into the vacuum degassing furnace for melting, and the melting is maintained for 3-8 hours. After melting is completed, the casting is carried out using a pull-stop process to obtain the initial billet. It is necessary to strictly control the mass percentage of the raw material components within the specified range. S2. The head and tail of the initial billet are cut off by a sawing machine and its surface is inspected. Then the initial billet is subjected to step-by-step continuous annealing and heating, and is rolled into a billet with a thickness of 20mm by a hot rolling mill. Then the 20mm thick billet is milled by a milling machine to obtain a billet with a thickness of 18mm. S3. The 18mm thick billet is rough rolled to open the billet. It takes 8 rolling passes to get from 18mm to 2.5mm. The rolling process is as follows: 18mm-15.3mm-12mm-9.3mm-7.3mm-5.5mm-4.3mm-3.2mm-2.5mm to get a 2.5mm thick billet. Then the billet is first trimmed by rough trimming, and then cleaned and ground by thick cleaning line. S4. The thickness of the billet is rolled from 2.5mm to 1.0mm using a medium / finishing mill. Then, the 1.0mm thick billet is subjected to online solution heat treatment in a high-temperature hanging furnace and thick washing and grinding cleaning treatment. S5. The 1.0mm thick billet is rolled using an imported six-roll mill. The rolling process from 1.0mm to 0.3mm requires 5 passes. The rolling process is as follows: 1.0mm-0.8mm-0.63mm-0.5mm-0.38mm-0.3mm, to obtain a 0.3mm thick billet. Then, the billet is subjected to strip grinding and cleaning, and the billet is trimmed and deburred using a slitting machine. The trimming range on one side is 5-7mm. S6. The thickness of the billet is rolled from 0.3mm to 0.08mm using a 20-roll finishing mill. A total of 5 rolling passes are required. The rolling process is as follows: 0.3mm-0.23mm-0.18mm-0.14mm-0.11mm-0.08mm, thus obtaining a billet with a thickness of 0.08mm. Then, the billet is subjected to online solution heat treatment in a high-temperature hanging furnace. S7. The billet thickness is rolled again from 0.08mm to 0.05mm using a 20-roll finishing mill, requiring one rolling pass. The rolling process is as follows: 0.08mm-0.05mm, to obtain a billet with a thickness of 0.05mm. Then, the billet is degreased and cleaned through a cleaning line. After cleaning, it is aged in a bell furnace. After aging, the billet is degreased and cleaned again through a cleaning line. Finally, after bending and straightening and shearing, it is packaged and stored. The cleaning speed of the thick-walled grinding and cleaning in S4 is 20-30 m / min, and the grinding brush current is 0.8-1.2 A; and the cleaning speed of the thin-walled grinding and cleaning in S5 is 30-50 m / min, and the grinding brush current is 0.6-1.0 A. In steps S4 and S6, the annealing temperature of the hanging furnace is 980℃-1020℃, the annealing rate in step S4 is 2-4m / min, and the annealing rate in step S6 is 18-20m / min. The aging temperature of the bell-shaped furnace in S7 is 440℃-460℃, the heating time is 3-5h, and the holding time is 3-5h.

2. The method for preparing the ultra-thin rolled copper alloy material for high-elasticity environmentally friendly connectors as described in claim 1, characterized in that: In step S1, the heating power source for the vacuum degassing furnace melting is a medium-high frequency induction power source with a heating rate of 58℃ / s and a melting temperature controlled between 1260℃ and 1360℃.

3. The method for preparing the ultra-thin rolled copper alloy material for high-elasticity environmentally friendly connectors as described in claim 2, characterized in that: In step S1, when performing the pull-stop process on the molten material, the casting speed is 60m / min-80m / min, the crystallizer vibration frequency is 30-50 times / min, and the crystallizer vibration amplitude is 2-4mm.

4. The method for preparing the ultra-thin rolled copper alloy material for high-elasticity environmentally friendly connectors as described in claim 1, characterized in that: In step S2, when milling the surface of the casting billet, a total of two milling operations are performed. In the first operation, the top and bottom surfaces are milled by 0.6-0.8 mm each, and the two sides are milled by 1-2 mm each. In the second operation, the top and bottom surfaces are milled by 0.3-0.5 mm each, and the two sides are milled by 1-2 mm each.

5. The method for preparing the ultra-thin rolled copper alloy material for high-elasticity environmentally friendly connectors as described in claim 4, characterized in that: In step S2, the stepping furnace has a stepping heating temperature between 980℃ and 1000℃, which is 280℃-360℃ lower than the melting temperature, and is held at that temperature for 8-10 hours.

6. The method for preparing the ultra-thin rolled copper alloy material for high-elasticity environmentally friendly connectors as described in claim 1, characterized in that: In step S3, the rolling speed of the roughing mill is 80-120 m / min, and the front and rear tension is controlled at 40-60 kN. In step S5, the rolling speed of the six-roll mill is 150-200 m / min, and the front and rear tension is controlled at 30-50 kN. In steps S6 and S7, the rolling speed of the twenty-roll finishing mill is 200-300 m / min, and the front and rear tension is controlled at 5-10 kN.

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