High-bending stress relaxation-resistant copper-nickel-silicon alloy and preparation method thereof

Abstract

The invention provides a high-bending stress relaxation-resistant copper-nickel-silicon alloy and a preparation method thereof, and belongs to the field of copper-nickel-silicon alloy preparation. The high-bending stress relaxation-resistant copper-nickel-silicon alloy provided by the invention comprises the following chemical components in percentage by mass: 2.2-4.2% of Ni; 0.25% to 1.20% of Si; mg: 0.05 to 0.30%; 0.10% or less of Sn; 0.10% or less of Mn; 0.20% or less of Fe and the balance Cu. By optimizing the chemical components of the copper-nickel-silicon alloy, the high-strength and high-hardness copper-nickel-silicon alloy can be obtained, and meanwhile, the copper-nickel-silicon alloy can have excellent high-bending stress relaxation resistance. The result of the embodiment shows that the tensile strength of the copper-nickel-silicon alloy is larger than or equal to 750 MPa, the yield strength is larger than or equal to 690 MPa, the ductility is larger than or equal to 8.5%, the hardness is larger than or equal to 225 HV, and the stress relaxation resistance rate of 1000 h is larger than 99.50%.

Description

Technical Field

[0001] The present invention relates to the field of copper-nickel-silicon alloy preparation, and in particular to a high-bending stress relaxation-resistant copper-nickel-silicon alloy and a preparation method thereof. Background Art

[0002] With the advancement of modern science and technology, the electronics, communications, and automotive industries are experiencing rapid growth, leading to an increasing demand for copper-based elastic alloys for elastic components such as docking plugs and connectors. Simultaneously, increasingly stringent performance requirements are being placed on copper-based elastic alloys, such as high strength, high conductivity, high elasticity, high stress relaxation resistance, and high fatigue strength. Cu-Ni-Si alloys are a class of copper-based elastic materials that exhibit high strength, high elasticity, high fatigue resistance, high conductivity, and excellent stress relaxation resistance, making them suitable for elastic components such as connectors and electrical connectors. However, Cu-Ni-Si alloys exhibit relatively poor stress relaxation resistance. To improve the stress relaxation resistance of Cu-Ni-Si alloys, elements such as Co and Cr are often added. These elements are expensive, increasing production costs. Furthermore, the resulting copper-nickel-silicon alloy exhibits good stress relaxation resistance only for 100 hours. Beyond that, the stress relaxation rate rapidly decreases, making it unable to meet the requirements of modern scientific and technological development. Therefore, how to provide a copper-nickel-silicon alloy with excellent mechanical properties and excellent stress relaxation resistance has become a technical problem that needs to be solved urgently in this field. Summary of the Invention

[0003] The object of the present invention is to provide a high-bending stress relaxation-resistant copper-nickel-silicon alloy and a preparation method thereof. The high-bending stress relaxation-resistant copper-nickel-silicon alloy provided by the present invention not only has excellent mechanical properties, but also has excellent stress relaxation resistance for 1000h.

[0004] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0005] The invention provides a high-bending stress relaxation-resistant copper-nickel-silicon alloy, which comprises the following chemical components by mass percentage: Ni: 2.2-4.2%; Si: 0.25-1.20%; Mg: 0.05-0.30%; Sn≤0.10%; Mn≤0.10%; Fe≤0.20% and the balance Cu.

[0006] Preferably, the steel comprises the following chemical components by mass percentage: Ni: 2.6-3.6%; Si: 0.5-1.00%; Mg: 0.10-0.25%; Sn: 0.001-0.10%; Mn: 0.0001-0.10%; Fe: 0.001-0.20% and the balance Cu.

[0007] The present invention provides a method for preparing the high-bending stress relaxation-resistant copper-nickel-silicon alloy described in the above technical solution, comprising the following steps:

[0008] (1) melting the alloy raw materials and performing semi-continuous casting to obtain an alloy ingot;

[0009] (2) hot rolling, initial rolling and intermediate continuous annealing are performed on the alloy ingot obtained in step (1) to obtain a first annealed ingot;

[0010] (3) subjecting the first annealed ingot obtained in step (2) to pre-finished product rolling and pre-finished product continuous annealing in sequence to obtain a second annealed ingot;

[0011] (4) The second annealed ingot obtained in step (3) is subjected to finished product rolling and finished product bell-type annealing in sequence to obtain a high-bending stress relaxation-resistant copper-nickel-silicon alloy.

[0012] Preferably, the casting temperature of the semi-continuous casting in step (1) is 1200-1300° C.; and the casting speed of the semi-continuous casting is 60-140 mm / min.

[0013] Preferably, the total processing rate of hot rolling in step (2) is 80-95%; and the number of passes of hot rolling is 9-15.

[0014] Preferably, the total processing rate of the initial rolling in step (2) is 85-98%; the processing number of the initial rolling is 12-14; and the initial rolling is cold rolling.

[0015] Preferably, the holding temperature of the intermediate continuous annealing in step (2) is 800-850° C.; and the holding time of the intermediate continuous annealing is 20-60 seconds.

[0016] Preferably, the total processing rate of the pre-finished product rolling in the step (3) is 55-65%; the processing passes of the pre-finished product rolling are 4-6 passes; and the pre-finished product rolling is cold rolling.

[0017] Preferably, the holding temperature of the pre-finished product during continuous annealing in step (3) is 800-900° C.; and the holding time of the pre-finished product during continuous annealing is 20-40 seconds.

[0018] Preferably, the temperature of the bell-jar annealing of the finished product in step (4) is 400-500° C.; and the holding time of the bell-jar annealing of the finished product is 6-12 hours.

[0019] The present invention provides a high bending stress relaxation resistant copper-nickel-silicon alloy, which comprises the following chemical components by mass percentage: Ni: 2.2-4.2%; Si: 0.25-1.20%; Mg: 0.05-0.30%; Sn≤0.10%; Mn≤0.10%; Fe≤0.20% and the balance Cu. In the present invention, nickel and silicon form a nano-scale Ni2Si precipitate phase in the copper matrix, which significantly improves the strength and hardness of the alloy through precipitation strengthening; and nickel can hinder the grain coarsening of the copper matrix during high-temperature processing (such as hot rolling), inhibit grain growth, and improve material uniformity, while silicon can refine grains and improve the structural stability of the alloy at high temperatures; the present invention can refine the Ni2Si precipitate phase by adding Mg element, and magnesium interacts with silicon and nickel to promote the precipitation of finer and more uniform Ni2Si precipitate phases, significantly improving the strength and hardness of the alloy; at the same time, magnesium is segregated at the grain boundaries of the copper alloy, which can prevent Grain coarsening; tin atoms dissolve in the copper matrix, causing lattice distortion, hindering dislocation movement, and improving the strength and hardness of the alloy; a small amount of tin can delay the aggregation and growth of the Ni2Si phase at high temperature, maintaining the size of the nano-scale precipitated phase; manganese mainly plays the role of deoxidation, grain refinement, improving heat resistance and corrosion resistance, and optimizing the processing performance of the alloy; adding a small amount of Fe element can segregate at the grain boundary, hinder recrystallization, and reduce grain size; the present invention optimizes the chemical composition of the copper-nickel-silicon alloy, not only to obtain a high-strength and high-hardness copper-nickel-silicon alloy, but also to make it have excellent high-bending stress relaxation resistance. The results of the embodiment show that the high-bending stress relaxation resistance copper-nickel-silicon alloy provided by the present invention has a tensile strength of ≥750MPa, a yield strength of ≥690MPa, an elongation of ≥8.5%, a hardness of ≥225HV, and a stress relaxation rate of 1000h of >99.50%. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 1000h stress relaxation curve of the copper-nickel-silicon alloy provided in Example 1 of the present invention;

[0021] Figure 2 This is the 1000h stress relaxation curve of the copper-nickel-silicon alloy provided in Comparative Example 1. DETAILED DESCRIPTION

[0022] The invention provides a high-bending stress relaxation-resistant copper-nickel-silicon alloy, which comprises the following chemical components by mass percentage: Ni: 2.2-4.2%; Si: 0.25-1.20%; Mg: 0.05-0.30%; Sn≤0.10%; Mn≤0.10%; Fe≤0.20% and the balance Cu.

[0023] The high-bending stress relaxation-resistant copper-nickel-silicon alloy provided by the present invention includes 2.2 to 4.2% Ni by mass. As one embodiment of the present invention, the mass percentage of Ni can be 2.4%, 2.6%, 2.8%, 3.0%, 3.2%, 3.4%, 3.6%, 3.8%, or 4.0%. In the present invention, nickel and silicon form a nano-scale Ni2Si precipitate phase in the copper matrix, significantly improving the strength and hardness of the alloy through precipitation strengthening. Nickel can hinder the grain coarsening of the copper matrix during high-temperature processing (such as hot rolling), inhibit grain growth, and improve material uniformity.

[0024] The high-bending stress relaxation-resistant copper-nickel-silicon alloy provided by the present invention comprises 0.25% to 1.20% Si by mass. In one embodiment of the present invention, the Si mass percentage may be 0.30%, 0.40%, 0.50%, 0.60%, 0.70%, 0.80%, 0.90%, 1.00%, 1.10%, or 1.15%. In the present invention, nickel and silicon form a nanoscale Ni2Si precipitate phase in the copper matrix, significantly improving the strength and hardness of the alloy through precipitation strengthening. Silicon also refines the grains, improving the alloy's structural stability at high temperatures.

[0025] The high-bending stress relaxation-resistant copper-nickel-silicon alloy provided by the present invention includes 0.05% to 0.30% Mg by mass. As one embodiment of the present invention, the Mg content can be 0.10%, 0.15%, 0.20%, or 0.25%. The addition of Mg refines the Ni2Si precipitate phase. The interaction of magnesium with silicon and nickel promotes the formation of finer, more uniform Ni2Si precipitates, significantly improving the alloy's strength and hardness. Furthermore, magnesium segregates at grain boundaries, preventing grain coarsening.

[0026] The high-bending stress relaxation-resistant copper-nickel-silicon alloy provided by the present invention includes Sn ≤ 0.10%, preferably 0.001-0.10%. As an embodiment of the present invention, the mass percentage of Sn can be 0.002%, 0.003%, 0.0036%, 0.004%, 0.0053%, 0.0063%, 0.007%, 0.008%, 0.009%, 0.01%, 0.02%, 0.05% or 0.08%. In the present invention, tin atoms are solid-dissolved in the copper matrix, causing lattice distortion, hindering dislocation movement, and improving the strength and hardness of the alloy; at the same time, a small amount of tin can delay the aggregation and growth of the Ni2Si phase at high temperature, maintaining the size of the nanoscale precipitate phase.

[0027] The high-bending stress relaxation-resistant copper-nickel-silicon alloy provided by the present invention includes Mn ≤ 0.10%, preferably 0.0001% to 0.10%. As one embodiment of the present invention, the mass percentage of Mn can be 0.0002%, 0.0005%, 0.001%, 0.0026%, 0.0036%, 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.06%, 0.07%, 0.08%, or 0.09%. In the present invention, manganese primarily plays a role in deoxidation, grain refinement, and improving heat resistance and corrosion resistance, while also optimizing the alloy's processing properties.

[0028] The high-bending stress relaxation-resistant copper-nickel-silicon alloy provided by the present invention includes Fe ≤ 0.20%, preferably 0.001-0.20%. As one embodiment of the present invention, the Fe mass percentage can be 0.002%, 0.005%, 0.0098%, 0.02%, 0.025%, 0.03%, 0.05%, 0.08%, 0.10%, 0.12%, 0.14%, 0.16%, or 0.18%. In the present invention, the addition of a small amount of Fe can segregate at grain boundaries, hinder recrystallization, and reduce grain size.

[0029] The high-bending stress relaxation-resistant copper-nickel-silicon alloy provided by the present invention preferably also includes P ≤ 0.01%, preferably 0.001-0.01%. As one embodiment of the present invention, the P mass percentage may be 0.0021%, 0.003%, 0.0044%, 0.0053%, 0.006%, 0.007%, 0.008%, or 0.009%. In the present invention, P is an impurity element and its content needs to be reduced as much as possible.

[0030] The high-bending stress relaxation-resistant copper-nickel-silicon alloy provided by the present invention preferably also includes S ≤ 0.01%, preferably 0.001-0.01%, by mass. In one embodiment of the present invention, the mass percentage of S can be 0.0019%, 0.0029%, or 0.00244%. In the present invention, S is an impurity element, and its content should be minimized.

[0031] The high bending stress relaxation resistant copper-nickel-silicon alloy provided by the present invention preferably further comprises a balance of copper, calculated by mass percentage. In the present invention, the copper is a matrix element of the copper-nickel-silicon alloy.

[0032] In the present invention, nickel and silicon form a nano-scale Ni2Si precipitate phase in the copper matrix, which significantly improves the strength and hardness of the alloy through precipitation strengthening; nickel can hinder the grain coarsening of the copper matrix during high-temperature processing (such as hot rolling), inhibit grain growth, and improve material uniformity, while silicon can refine the grains and improve the structural stability of the alloy at high temperatures; the present invention can play a role in refining the Ni2Si precipitate phase by adding Mg element, and magnesium interacts with silicon and nickel to promote the precipitation of finer and more uniform Ni2Si precipitate phase, significantly improving the strength and hardness of the alloy; at the same time, magnesium segregates at the grain boundaries of the copper alloy, which can prevent Grain coarsening; tin atoms are dissolved in the copper matrix, causing lattice distortion, hindering dislocation movement, and improving the strength and hardness of the alloy; a small amount of tin can delay the aggregation and growth of Ni2Si phase at high temperature and maintain the size of nano-scale precipitated phase; manganese mainly plays the role of deoxidation, grain refinement, improving heat resistance and corrosion resistance, and optimizing the processing performance of the alloy; adding a small amount of Fe element can segregate at the grain boundary, hinder recrystallization, and reduce grain size; the present invention optimizes the chemical composition of the copper-nickel-silicon alloy, not only can obtain a copper-nickel-silicon alloy with high strength and hardness, but also can make it have excellent high bending stress relaxation resistance.

[0033] The present invention also provides a method for preparing the high bending stress relaxation resistant copper-nickel-silicon alloy described in the above technical solution, comprising the following steps:

[0034] (1) melting the alloy raw materials and performing semi-continuous casting to obtain an alloy ingot;

[0035] (2) hot rolling, initial rolling and intermediate continuous annealing are performed on the alloy ingot obtained in step (1) to obtain a first annealed ingot;

[0036] (3) subjecting the first annealed ingot obtained in step (2) to pre-finished product rolling and pre-finished product continuous annealing in sequence to obtain a second annealed ingot;

[0037] (4) The second annealed ingot obtained in step (3) is subjected to finished product rolling and finished product bell-type annealing in sequence to obtain a high-bending stress relaxation-resistant copper-nickel-silicon alloy.

[0038] The invention performs semi-continuous casting after melting alloy raw materials to obtain alloy ingots.

[0039] The present invention has no particular limitation on the specific type and amount of the alloy raw materials, as long as the composition of the high bending stress relaxation resistant copper-nickel-silicon alloy meets the requirements.

[0040] The present invention does not specifically limit the temperature and time of the smelting. It can be determined according to the technical common sense of those skilled in the art, as long as the alloy raw materials can be completely melted and evenly mixed. As an embodiment of the present invention, the holding temperature of the smelting can be 1200-1300°C, or 1210°C, 1220°C, 1230°C, 1240°C, 1250°C, 1260°C, 1270°C, 1280°C, or 1290°C; the holding time of the smelting can be 15-30 minutes, or 18 minutes, 20 minutes, 22 minutes, 25 minutes, or 28 minutes. By controlling the holding temperature and holding time of the smelting, the present invention can effectively improve the uniformity of the copper alloy melt and reduce the segregation of the ingot.

[0041] In the present invention, the casting temperature of the semi-continuous casting is preferably 1200-1300°C; the pulling speed of the semi-continuous casting is preferably 60-140 mm / min. As one embodiment of the present invention, the casting temperature of the semi-continuous casting can be 1210°C, 1220°C, 1230°C, 1240°C, 1250°C, 1260°C, 1270°C, 1280°C, or 1290°C; and the pulling speed of the semi-continuous casting can be 70 mm / min, 80 mm / min, 90 mm / min, 100 mm / min, 110 mm / min, 120 mm / min, or 130 mm / min. By controlling the casting temperature and pulling speed of the semi-continuous casting, the present invention can achieve an appropriate cooling rate for the copper alloy melt, thereby obtaining a uniform and fine ingot structure and reducing casting defects such as shrinkage and shrinkage cavities.

[0042] After obtaining the alloy ingot, the present invention sequentially performs hot rolling, initial rolling and intermediate continuous annealing on the alloy ingot to obtain a first annealed ingot.

[0043] The present invention preferably performs a holding treatment on the alloy ingot before hot rolling; the holding temperature for the holding treatment is preferably 850-1000°C, and the holding time for the holding treatment is preferably 8-10 hours. In one embodiment of the present invention, the holding temperature for the holding treatment can be 900-950°C, and the holding time for the holding treatment can be 9 hours. Through the holding treatment, the temperature of the alloy ingot can be brought to the required temperature for hot rolling.

[0044] In the present invention, the total hot rolling processing rate is preferably 80-95%, and the number of hot rolling passes is preferably 9-15. As one embodiment of the present invention, the total hot rolling processing rate can be 82%, 85%, 88%, 90%, or 92%, and the number of hot rolling passes can be 10, 11, 12, 13, or 14. The present invention uses hot rolling to significantly reduce the thickness of the alloy ingot, change its microstructure, and improve its performance.

[0045] The present invention preferably further comprises milling the hot-rolled product. The present invention has no particular limitation on the specific operation and thickness of the milling, as long as the oxide layer on the surface of the alloy ingot can be removed.

[0046] In the present invention, the total processing rate of the initial rolling is preferably 85-98%, the number of initial rolling passes is preferably 12-14, and the initial rolling is preferably cold rolling. In one embodiment of the present invention, the total processing rate of the initial rolling can be 88%, 90%, 92%, or 95%, and the number of initial rolling passes can be 13. The present invention utilizes initial rolling to significantly reduce the thickness of the alloy ingot and to break up the coarse grains within the alloy ingot, thereby optimizing the structure and properties of the alloy ingot.

[0047] The present invention preferably further comprises unwinding the initially rolled product. The present invention has no particular limitation on the specific operation of unwinding, and any unwinding operation well known to those skilled in the art can be used.

[0048] In the present invention, the holding temperature of the intermediate continuous annealing is preferably 800-850°C; the holding time of the intermediate continuous annealing is preferably 20-60s. As an embodiment of the present invention, the holding temperature of the intermediate continuous annealing can be 810°C, 820°C, 830°C or 840°C; the holding time of the intermediate continuous annealing can be 25s, 30s, 35s, 40s, 45s, 50s or 55s. The present invention can eliminate work hardening and restore plasticity through intermediate continuous annealing, facilitating subsequent processing. At the same time, it can also regulate the grain size, avoid excessive grain growth, ensure the balance between strength and plasticity, and inhibit the premature precipitation of the Ni2Si phase.

[0049] The present invention preferably further comprises brushing the intermediate continuous annealing product. The present invention has no particular limitation on the specific operation of brushing, and a brushing operation well known to those skilled in the art can be used to clean the surface of the ingot.

[0050] In the present invention, the thickness of the first annealing ingot is preferably 0.7-0.8 mm.

[0051] After obtaining the first annealed ingot, the present invention sequentially performs pre-finished product rolling and pre-finished product continuous annealing on the first annealed ingot to obtain the second annealed ingot.

[0052] In the present invention, the total processing rate of the pre-rolled product is preferably 55-65%, the number of processing passes of the pre-rolled product is preferably 4-6, and the pre-rolled product is preferably cold-rolled. In one embodiment of the present invention, the total processing rate of the pre-rolled product can be 58%, 60%, or 63%, and the number of processing passes of the pre-rolled product can be 5. The pre-rolled product of the present invention can significantly reduce the size of the annealed ingot and further break up the grains in the alloy, thereby refining the grains and further improving the mechanical properties of the alloy ingot.

[0053] In the present invention, the holding temperature of the continuous annealing of the pre-finished product is preferably 800-900°C; the holding time of the continuous annealing of the pre-finished product is preferably 20-40s; the cooling method after the continuous annealing of the pre-finished product is preferably rapid cooling, more preferably air cooling or water cooling. As an embodiment of the present invention, the holding temperature of the continuous annealing of the pre-finished product can be 810°C, 820°C, 830°C, 840°C, 850°C, 860°C, 870°C, 880°C or 890°C; the holding time of the continuous annealing of the pre-finished product can be 25s, 30s or 35s. The present invention can eliminate the work hardening caused by the rolling of the pre-finished product through continuous annealing of the pre-finished product, restore plasticity, facilitate subsequent processing, and further refine the grains.

[0054] In the present invention, the thickness of the second annealing ingot is preferably 0.25 to 0.3 mm.

[0055] After obtaining the second annealing ingot, the present invention sequentially performs finished product rolling and finished product bell-type annealing on the second annealing ingot to obtain a high-bending stress relaxation-resistant copper-nickel-silicon alloy.

[0056] In the present invention, the total processing rate of the finished product rolling is preferably 10-28%, and the number of processing passes of the finished product rolling is preferably 1-2. As an embodiment of the present invention, the total processing rate of the finished product rolling can be 12%, 14%, 16%, 18%, 20%, 22%, 24%, or 26%. The present invention controls the size of the copper-nickel-silicon alloy through finished product rolling to achieve a thickness that meets the requirements.

[0057] The present invention preferably further comprises unwinding the finished rolled product. The present invention has no particular limitation on the specific operation of unwinding, and any unwinding method well known to those skilled in the art can be used.

[0058] In the present invention, the temperature of the finished product bell-jar annealing is preferably 400-500°C; the holding time of the finished product bell-jar annealing is preferably 6-12h. As an embodiment of the present invention, the temperature of the finished product bell-jar annealing can be 410°C, 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C or 490°C; the holding time of the finished product bell-jar annealing can be 7h, 8h, 9h, 10h or 11h. The present invention can achieve complete recrystallization and softening through the finished product bell-jar annealing, eliminate work hardening, and completely recrystallize the deformed grains after cold rolling and restore plasticity; at the same time, it can also achieve grain size control and avoid premature precipitation of Ni2Si.

[0059] The present invention preferably further includes pickling the finished bell-annealed product. In the present invention, the mass concentration of the acid in the pickling solution used during pickling is preferably 10-25%; the mass concentration of the passivating solution in the pickling solution is preferably 0.025-0.070%. As one embodiment of the present invention, the mass concentration of the acid in the pickling solution used during pickling can be 11%, 12%, 15%, 18%, 20%, 22%, or 24%; the mass concentration of the passivating solution in the pickling solution can be 0.030%, 0.035%, 0.040%, 0.045%, 0.050%, 0.055%, 0.060%, or 0.065%. Pickling can remove rolling oil and oxide layers from the surface of the copper-nickel-silicon alloy.

[0060] The preparation method provided by the invention is simple, and the equipment used is conventional equipment, which is suitable for large-scale industrial promotion.

[0061] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0062] Example 1

[0063] A high bending stress relaxation resistant copper-nickel-silicon alloy, composed of the following chemical components by mass percentage: Ni: 2.72%; Si: 0.596%; Mg: 0.09%; Sn: 0.0036%; Mn: 0.0002%; Fe: 0.0098%; P: 0.0021%; S: 0.00244% and the balance Cu;

[0064] The preparation method of the high-bending stress relaxation-resistant copper-nickel-silicon alloy comprises the following steps:

[0065] (1) melting the alloy raw materials and performing semi-continuous casting to obtain an alloy ingot; the holding temperature of the melting is 1280° C., and the holding time of the melting is 25 minutes; the casting temperature of the semi-continuous casting is 1250° C., and the casting speed of the semi-continuous casting is 80 mm / min;

[0066] (2) the alloy ingot obtained in the step (1) is kept at 950° C. for 10 hours and then hot rolled, milled, rolled, unrolled, intermediate continuous annealed and brushed in sequence to obtain a first annealed ingot with a thickness of 0.7 mm; the total processing rate of the hot rolling is 93%, and the number of hot rolling passes is 13; the total processing rate of the initial rolling is 95%, and the number of initial rolling passes is 12, and the initial rolling is cold rolled; the holding temperature of the intermediate continuous annealing is 850° C., and the holding time of the intermediate continuous annealing is 30 seconds;

[0067] (3) The first annealed ingot obtained in step (2) is subjected to pre-finished product rolling and pre-finished product continuous annealing in sequence to obtain a second annealed ingot with a thickness of 0.27 mm; the total processing rate of the pre-finished product rolling is 61%, the number of processing passes of the pre-finished product rolling is 5, and the pre-finished product rolling is cold rolling; the holding temperature of the pre-finished product continuous annealing is 850° C., the holding time of the pre-finished product continuous annealing is 30 seconds, and the cooling method of the pre-finished product after the continuous annealing is air cooling;

[0068] (4) The second annealed ingot obtained in the step (3) is subjected to finished product rolling, unwinding, finished product bell-shaped annealing and pickling in sequence to obtain a high-bending stress relaxation-resistant copper-nickel-silicon alloy with a thickness of 0.2 mm; the total processing rate of the finished product rolling is 26%, and the number of processing passes of the finished product rolling is 1 pass; the temperature of the finished product bell-shaped annealing is 450° C., and the holding time of the finished product bell-shaped annealing is 9 hours; the mass concentration of acid in the pickling solution used in the pickling is 15%, and the mass concentration of the passivation solution is 0.05%.

[0069] Example 2

[0070] A high bending stress relaxation resistant copper-nickel-silicon alloy, composed of the following chemical components by mass percentage: Ni: 2.78%; Si: 0.633%; Mg: 0.114%; Sn: 0.0053%; Mn: 0.0036%; Fe: 0.02%; P: 0.0053%; S: 0.0029% and the balance Cu;

[0071] The preparation method of the high-bending stress relaxation-resistant copper-nickel-silicon alloy comprises the following steps:

[0072] (1) melting the alloy raw materials and performing semi-continuous casting to obtain an alloy ingot; the holding temperature of the melting is 1280° C., and the holding time of the melting is 25 minutes; the casting temperature of the semi-continuous casting is 1250° C., and the casting speed of the semi-continuous casting is 80 mm / min;

[0073] (2) the alloy ingot obtained in the step (1) is kept at 950° C. for 10 hours and then hot rolled, milled, rolled, unrolled, intermediate continuous annealed and brushed in sequence to obtain a first annealed ingot with a thickness of 0.7 mm; the total processing rate of the hot rolling is 93%, and the number of hot rolling passes is 13; the total processing rate of the initial rolling is 95%, and the number of initial rolling passes is 12, and the initial rolling is cold rolled; the holding temperature of the intermediate continuous annealing is 850° C., and the holding time of the intermediate continuous annealing is 30 seconds;

[0074] (3) The first annealed ingot obtained in step (2) is subjected to pre-finished product rolling and pre-finished product continuous annealing in sequence to obtain a second annealed ingot with a thickness of 0.27 mm; the total processing rate of the pre-finished product rolling is 61%, the number of processing passes of the pre-finished product rolling is 5, and the pre-finished product rolling is cold rolling; the holding temperature of the pre-finished product continuous annealing is 850° C., the holding time of the pre-finished product continuous annealing is 30 seconds, and the cooling method of the pre-finished product after the continuous annealing is air cooling;

[0075] (4) The second annealed ingot obtained in the step (3) is subjected to finished product rolling, unwinding, finished product bell-shaped annealing and pickling in sequence to obtain a high-bending stress relaxation-resistant copper-nickel-silicon alloy with a thickness of 0.2 mm; the total processing rate of the finished product rolling is 26%, and the number of processing passes of the finished product rolling is 1 pass; the temperature of the finished product bell-shaped annealing is 450° C., and the holding time of the finished product bell-shaped annealing is 9 hours; the mass concentration of acid in the pickling solution used in the pickling is 15%, and the mass concentration of the passivation solution is 0.05%.

[0076] Example 3

[0077] A copper-nickel-silicon alloy with high bending resistance and stress relaxation resistance, composed of the following chemical components by mass percentage: Ni: 2.54%; Si: 0.554%; Mg: 0.102%; Sn: 0.0063%; Mn: 0.0026%; Fe: 0.025%; P: 0.0044%; S: 0.0019% and the balance Cu;

[0078] The preparation method of the high-bending stress relaxation-resistant copper-nickel-silicon alloy comprises the following steps:

[0079] (1) melting the alloy raw materials and performing semi-continuous casting to obtain an alloy ingot; the holding temperature of the melting is 1280° C., and the holding time of the melting is 25 minutes; the casting temperature of the semi-continuous casting is 1250° C., and the casting speed of the semi-continuous casting is 80 mm / min;

[0080] (2) the alloy ingot obtained in the step (1) is kept at 950° C. for 10 hours and then hot rolled, milled, rolled, unrolled, intermediate continuous annealed and brushed in sequence to obtain a first annealed ingot with a thickness of 0.7 mm; the total processing rate of the hot rolling is 93%, and the number of hot rolling passes is 13; the total processing rate of the initial rolling is 95%, and the number of initial rolling passes is 12, and the initial rolling is cold rolled; the holding temperature of the intermediate continuous annealing is 850° C., and the holding time of the intermediate continuous annealing is 30 seconds;

[0081] (3) The first annealed ingot obtained in step (2) is subjected to pre-finished product rolling and pre-finished product continuous annealing in sequence to obtain a second annealed ingot with a thickness of 0.27 mm; the total processing rate of the pre-finished product rolling is 61%, the number of processing passes of the pre-finished product rolling is 5, and the pre-finished product rolling is cold rolling; the holding temperature of the pre-finished product continuous annealing is 850° C., the holding time of the pre-finished product continuous annealing is 30 seconds, and the cooling method of the pre-finished product after the continuous annealing is air cooling;

[0082] (4) The second annealed ingot obtained in the step (3) is subjected to finished product rolling, unwinding, finished product bell-shaped annealing and pickling in sequence to obtain a high-bending stress relaxation-resistant copper-nickel-silicon alloy with a thickness of 0.2 mm; the total processing rate of the finished product rolling is 26%, and the number of processing passes of the finished product rolling is 1 pass; the temperature of the finished product bell-shaped annealing is 450° C., and the holding time of the finished product bell-shaped annealing is 9 hours; the mass concentration of acid in the pickling solution used in the pickling is 15%, and the mass concentration of the passivation solution is 0.05%.

[0083] Example 4

[0084] A copper-nickel-silicon alloy with high bending resistance and stress relaxation resistance, comprising the following chemical components by mass percentage: Ni: 2.78%; Si: 0.633%; Mg: 0.114%; Sn: 0.0053%; Mn: 0.0026%; Fe: 0.025%; P: 0.0053%; S: 0.0029% and the balance Cu;

[0085] The preparation method of the high-bending stress relaxation-resistant copper-nickel-silicon alloy comprises the following steps:

[0086] (1) melting the alloy raw materials and performing semi-continuous casting to obtain an alloy ingot; the holding temperature of the melting is 1280° C., and the holding time of the melting is 25 minutes; the casting temperature of the semi-continuous casting is 1250° C., and the casting speed of the semi-continuous casting is 80 mm / min;

[0087] (2) the alloy ingot obtained in the step (1) is kept at 950° C. for 10 hours and then hot rolled, milled, rolled, unrolled, intermediate continuous annealed and brushed in sequence to obtain a first annealed ingot with a thickness of 0.7 mm; the total processing rate of the hot rolling is 93%, and the number of hot rolling passes is 13; the total processing rate of the initial rolling is 95%, and the number of initial rolling passes is 12, and the initial rolling is cold rolled; the holding temperature of the intermediate continuous annealing is 850° C., and the holding time of the intermediate continuous annealing is 30 seconds;

[0088] (3) The first annealed ingot obtained in step (2) is subjected to pre-finished product rolling and pre-finished product continuous annealing in sequence to obtain a second annealed ingot with a thickness of 0.27 mm; the total processing rate of the pre-finished product rolling is 61%, the number of processing passes of the pre-finished product rolling is 5, and the pre-finished product rolling is cold rolling; the holding temperature of the pre-finished product continuous annealing is 850° C., the holding time of the pre-finished product continuous annealing is 30 seconds, and the cooling method of the pre-finished product after the continuous annealing is air cooling;

[0089] (4) The second annealed ingot obtained in the step (3) is subjected to finished product rolling, unwinding, finished product bell-shaped annealing and pickling in sequence to obtain a high-bending stress relaxation-resistant copper-nickel-silicon alloy with a thickness of 0.2 mm; the total processing rate of the finished product rolling is 26%, and the number of processing passes of the finished product rolling is 1 pass; the temperature of the finished product bell-shaped annealing is 450° C., and the holding time of the finished product bell-shaped annealing is 9 hours; the mass concentration of acid in the pickling solution used in the pickling is 15%, and the mass concentration of the passivation solution is 0.05%.

[0090] Comparative Example 1

[0091] A high-strength, high-conductivity, stress-relaxation-resistant copper-nickel-silicon alloy material, composed of the following components by mass percentage: Ni: 1.5%; Co: 0.9%; Si: 0.5% and the balance copper;

[0092] The preparation method comprises the following steps:

[0093] (1) Melting: Add alloy raw materials into a non-vacuum induction furnace, raise the temperature to 1300℃, stir evenly after the melt is completely melted, control the casting temperature at 1240℃, keep warm for 30 minutes and then cast;

[0094] (2) Hot rolling: The alloy ingot is placed in a walking beam furnace and heated at 1000°C for 4 hours, and then hot rolled. The final rolling temperature is controlled at 800°C, and then water-cooled.

[0095] (3) Solution treatment: The alloy ingot was placed in a box furnace and heated at 900°C for 6 h, followed by water cooling.

[0096] (4) One-step cold rolling: The milled alloy plate is placed in a liquid nitrogen environment for one-step cold rolling, with a cold rolling processing rate of 75%;

[0097] (5) Primary aging treatment: The cold-rolled plate is placed in a box-type annealing furnace for primary aging treatment. The aging temperature is 600°C, the holding time is 1 hour, and the cooling method is air cooling.

[0098] (6) Secondary cold rolling: The alloy plate after aging treatment is placed in a liquid nitrogen environment for secondary cold rolling, and the cold rolling processing rate is 30%;

[0099] (7) Secondary aging treatment: The cold-rolled plate is placed in a box-type annealing furnace for secondary aging treatment. The aging temperature is 350°C, the holding time is 16 hours, and the cooling method is air cooling.

[0100] Comparative Example 2

[0101] A copper-nickel-silicon alloy, comprising the following chemical components by mass percentage: Ni: 2.72%; Si: 0.596%; Mg: 0.09%; P: 0.0032%; S: 0.0027% and the balance Cu;

[0102] The preparation method of the high-bending stress relaxation-resistant copper-nickel-silicon alloy comprises the following steps:

[0103] (1) melting the alloy raw materials and performing semi-continuous casting to obtain an alloy ingot; the holding temperature of the melting is 1280° C., and the holding time of the melting is 25 minutes; the casting temperature of the semi-continuous casting is 1250° C., and the casting speed of the semi-continuous casting is 80 mm / min;

[0104] (2) the alloy ingot obtained in the step (1) is kept at 950° C. for 10 hours and then hot rolled, milled, rolled, unrolled, intermediate continuous annealed and brushed in sequence to obtain a first annealed ingot with a thickness of 0.7 mm; the total processing rate of the hot rolling is 93%, and the number of hot rolling passes is 13; the total processing rate of the initial rolling is 95%, and the number of initial rolling passes is 12, and the initial rolling is cold rolled; the holding temperature of the intermediate continuous annealing is 850° C., and the holding time of the intermediate continuous annealing is 30 seconds;

[0105] (3) The first annealed ingot obtained in step (2) is subjected to pre-finished product rolling and pre-finished product continuous annealing in sequence to obtain a second annealed ingot with a thickness of 0.27 mm; the total processing rate of the pre-finished product rolling is 61%, the number of processing passes of the pre-finished product rolling is 5, and the pre-finished product rolling is cold rolling; the holding temperature of the pre-finished product continuous annealing is 850° C., the holding time of the pre-finished product continuous annealing is 30 seconds, and the cooling method of the pre-finished product after the continuous annealing is air cooling;

[0106] (4) The second annealed ingot obtained in the step (3) is subjected to finished product rolling, unwinding, finished product bell-shaped annealing and pickling in sequence to obtain a high-bending stress relaxation-resistant copper-nickel-silicon alloy with a thickness of 0.2 mm; the total processing rate of the finished product rolling is 26%, and the number of processing passes of the finished product rolling is 1 pass; the temperature of the finished product bell-shaped annealing is 450° C., and the holding time of the finished product bell-shaped annealing is 9 hours; the mass concentration of acid in the pickling solution used in the pickling is 15%, and the mass concentration of the passivation solution is 0.05%.

[0107] Table 1 Properties of copper-nickel-silicon alloys prepared in Examples 1 to 4 and Comparative Examples 1 to 2

[0108]

[0109]

[0110] Among them, the test methods for tensile strength and yield strength are: GB / T 34505-2017 Room temperature tensile test method;

[0111] The test method for elongation is: GB / T 34505-2017 Room temperature tensile test method;

[0112] The test method for hardness is: GB / T 4340.1 Metallic materials Vickers hardness test Part 1: Test method;

[0113] The test method for 90° bending in the wrong direction is: GB / T 232 Metal Material Bending Test Method.

[0114] As can be seen from Table 1, the tensile strength, yield strength, elongation and hardness of the copper-nickel-silicon alloy provided by the present invention are basically the same as those of the existing copper-nickel-silicon alloy, indicating that the present invention does not cause a decrease in mechanical properties by adding other elements and optimizing their dosage.

[0115] The stress relaxation resistance of the copper-nickel-silicon alloy provided in Example 1 and Comparative Example 1 of the present invention was tested using the following test method: GB / T 39152 Copper and Copper Alloy Bending Stress Relaxation Test Method. The results are as follows: Figure 1 and Figure 2 shown.

[0116] Figure 1 1000h stress relaxation curve of the copper-nickel-silicon alloy provided in Example 1 of the present invention; Figure 2 The 1000h stress relaxation curve of the copper-nickel-silicon alloy provided in Comparative Example 1. Figure 1 and Figure 2 A comparison shows that the copper-nickel-silicon alloy provided by the present invention maintains a stress relaxation resistance of over 99.50% even after 1000 hours. However, the stress relaxation resistance of the stress relaxation-resistant copper-nickel-silicon alloy material provided by the prior art (Comparative Example 1) decreases rapidly over time and levels off after 100 hours. At this point, the stress relaxation resistance is only 80-85%, far lower than that of the present invention. This shows that the copper-nickel-silicon alloy provided by the present invention has superior stress relaxation resistance.

[0117] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A high bending stress relaxation resistant copper-nickel-silicon alloy, characterized in that: In terms of mass percentage, it includes the following chemical components: Ni: 2.2-4.2%; Si: 0.25-1.20%; Mg: 0.05~0.30%; Sn≤0.10%; Mn≤0.10%; Fe≤0.20% and the balance Cu.

2. The high bending stress relaxation resistant copper-nickel-silicon alloy according to claim 1, characterized in that: Calculated by mass percentage, it includes the following chemical components: Ni: 2.6-3.6%; Si: 0.5-1.00%; Mg: 0.10-0.25%; Sn: 0.001-0.10%; Mn: 0.0001-0.10%; Fe: 0.001-0.20% and the balance Cu.

3. The method for preparing the high bending stress relaxation resistant copper-nickel-silicon alloy according to claim 1 or 2, characterized in that: The following steps are involved: (1) melting the alloy raw materials and performing semi-continuous casting to obtain an alloy ingot; (2) hot rolling, initial rolling and intermediate continuous annealing are performed on the alloy ingot obtained in step (1) to obtain a first annealed ingot; (3) subjecting the first annealed ingot obtained in step (2) to pre-finished product rolling and pre-finished product continuous annealing in sequence to obtain a second annealed ingot; (4) The second annealed ingot obtained in step (3) is subjected to finished product rolling and finished product bell-type annealing in sequence to obtain a high-bending stress relaxation-resistant copper-nickel-silicon alloy.

4. The preparation method according to claim 3, characterized in that The casting temperature of the semi-continuous casting in the step (1) is 1200-1300° C.; the casting speed of the semi-continuous casting is 60-140 mm / min.

5. The preparation method according to claim 3, characterized in that The total processing rate of hot rolling in step (2) is 80-95%; the number of passes of hot rolling is 9-15.

6. The preparation method according to claim 3, characterized in that The total processing rate of the initial rolling in the step (2) is 85-98%; the processing passes of the initial rolling are 12-14 passes; and the initial rolling is cold rolling.

7. The preparation method according to claim 3, characterized in that The holding temperature of the intermediate continuous annealing in the step (2) is 800-850° C.; the holding time of the intermediate continuous annealing is 20-60 seconds.

8. The preparation method according to claim 3, characterized in that The total processing rate of the pre-finished product rolling in the step (3) is 55-65%; the processing passes of the pre-finished product rolling are 4-6 passes; and the pre-finished product rolling is cold rolling.

9. The preparation method according to claim 3, characterized in that The holding temperature of the continuous annealing of the pre-finished product in step (3) is 800-900° C.; the holding time of the continuous annealing of the pre-finished product is 20-40 seconds.

10. The preparation method according to claim 3, characterized in that The temperature of the bell-jar annealing of the finished product in step (4) is 400-500° C.; and the holding time of the bell-jar annealing of the finished product is 6-12 hours.

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