Tin brass alloy strip and preparation method and application thereof

Abstract

The invention provides a tin brass alloy strip and a preparation method and application thereof, and relates to the technical field of copper alloys. The tin brass alloy strip provided by the invention comprises the following components in percentage by mass: 90%-92% of Cu, 0.2%-0.8% of Ni, 0.3%-0.5% of Sn, 0.0001%-0.01% of P, 0.0001%-0.05% of Mg and the balance of Zn. The tensile strength of the tin brass alloy strip ranges from 460 MPa to 550 MPa, the percentage elongation after fracture A50 is larger than or equal to 7%, the hardness HV ranges from 145 to 165, the electric conductivity is larger than or equal to 35% IACS, the requirements of connectors, plugging terminals and the like for the material strength and the electric conductivity can be met, and cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of copper alloys, and in particular to a tin brass alloy strip and a preparation method and application thereof. Background Art

[0002] With the rapid development of modern electronic industry technology, electronic components have been developed towards high performance, precision and miniaturization, and higher requirements have been put forward for the elasticity, conductivity and reliability of the materials used. Integrated circuits, discrete semiconductor devices, relays and new contact components are important basic products of the electronic information industry. The performance and quality of the copper-based alloy strips used in these basic products will directly affect the function and quality of the assembled whole machine. Therefore, while vigorously developing electronic information products, it is necessary to develop high-quality and high-performance copper-based alloy strips as basic materials and their supporting materials accordingly.

[0003] For traditional brass, it is difficult to simultaneously meet the performance requirements of strength ≥450MPa and conductivity ≥35%IACS. Beryllium bronze and tin-phosphor bronze are the two most commonly used copper-based elastic alloys on the market. However, due to the high toxicity of beryllium oxides and dust and the high price of beryllium, the production and use of beryllium bronze alloys are greatly restricted. Tin-phosphor bronze has a high Sn content, generally 4% to 10%, which easily causes strong deformation strengthening of copper and a high work hardening rate, resulting in many cold working passes and a long production cycle during the production process. In addition, tin-phosphor bronze is prone to Sn reverse segregation during the production process, and it needs to be homogenized for a long time, which seriously affects the production efficiency of the alloy. In addition, Sn resources are relatively scarce and expensive. Adding high content of Sn increases production costs, affecting the industrialization and promotion and application of the alloy. Aging precipitation-strengthened alloys such as copper-chromium and copper-nickel-silicon have strong comprehensive performance, but the manufacturing cost is much higher than that of brass products, and are generally used in high-end fields.

[0004] At present, medium and high-end electronic connector materials are mainly used in the manufacturing of integrated circuit wiring jacks, plug-ins and various conductive elastic components such as multi-point connectors, plug-in terminals, sockets, etc. The current domestic demand is large, and the development of low-tin content elastic copper alloys has broad market prospects.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The first object of the present invention is to provide a tin-brass alloy strip to solve the above technical problems.

[0007] A second object of the present invention is to provide a method for preparing the above-mentioned tin-brass alloy strip.

[0008] The third object of the present invention is to provide application of the above-mentioned tin-brass alloy strip in the preparation of connectors.

[0009] In order to achieve the above objectives, the following technical solutions are adopted:

[0010] In a first aspect, the present invention provides a tin brass alloy strip, comprising, by mass percentage, 90% to 92% Cu, 0.2% to 0.8% Ni, 0.3% to 0.5% Sn, 0.0001% to 0.01% P, 0.0001% to 0.05% Mg, and the balance is Zn.

[0011] In a second aspect, the present invention provides a method for preparing the above-mentioned tin brass alloy strip, comprising the following steps:

[0012] The materials are prepared according to the mass percentage, and then smelting, casting, hot rolling, milling, the first cold rolling, the first recrystallization annealing, the second cold rolling, the second recrystallization annealing, the third cold rolling and low-temperature annealing are carried out in sequence to prepare a tin-brass alloy strip.

[0013] As a further technical solution, the smelting temperature is 1200-1220°C;

[0014] The casting process parameters include: a casting temperature of 1190-1210° C., a casting speed of 55-95 mm / min, and a cooling water flow rate of 50-75 cubic meters / hour.

[0015] As a further technical solution, the hot rolling start temperature is 800-850°C;

[0016] The final rolling temperature of the hot rolling is 450-500°C;

[0017] The total processing rate of the hot rolling is 90% to 95%.

[0018] As a further technical solution, the processing rate of the first cold rolling is 80% to 85%;

[0019] The processing rate of the second cold rolling is 40% to 50%;

[0020] The third cold rolling is performed to the finished product specification thickness.

[0021] As a further technical solution, the first recrystallization annealing is an intermediate annealing treatment, the annealing temperature is 400-420° C., and the holding time is 4-6 hours.

[0022] As a further technical solution, the second recrystallization annealing is a bell jar annealing treatment, the annealing temperature is 380-400° C., and the holding time is 4-6 hours.

[0023] As a further technical solution, the first recrystallization annealing and the second recrystallization annealing are performed under a protective atmosphere.

[0024] As a further technical solution, the annealing temperature of the low-temperature annealing treatment is 210-260° C., and the insulation time is 2-5 hours.

[0025] In a third aspect, the present invention provides a use of the above-mentioned tin-brass alloy strip in the preparation of a connector.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The tin brass alloy strip provided by the present invention is based on the Cu-Sn-Zn ternary alloy, and Ni, P and Mg elements are added. A small amount of Mg can refine the grains and improve the mechanical properties and bending properties of the material; the Ni element can make the material have a better work hardening effect, and at the same time, a trace amount of P element is added to form a Ni3P precipitation phase, which has a certain solid solution aging strengthening effect, and helps to further improve the mechanical properties and electrical conductivity of the material. The tensile strength of the tin brass alloy strip is 460-550MPa, and the elongation after fracture A 50 ≥7%, hardness HV145-165, conductivity ≥35% IACS, which can meet the requirements of connectors, plug terminals, etc. for material strength and conductivity, and has low cost. DETAILED DESCRIPTION

[0028] The embodiments of the present invention will be described in detail below in conjunction with the embodiments and examples, but it will be appreciated by those skilled in the art that the following embodiments and examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified, proceed according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified for the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0029] In a first aspect, the present invention provides a tin brass alloy strip mainly composed of Cu, Ni, Sn, P, Mg and Zn, wherein the content of the Cu element may be, for example, but not limited to 90%, 91% or 92%; the content of the Ni element may be, for example, but not limited to 0.2%, 0.4%, 0.6% or 0.8%; the content of the Sn element may be, for example, but not limited to 0.3%, 0.4% or 0.5%; the content of the P element may be, for example, but not limited to 0.0001%, 0.001% or 0.01%; the content of the Mg element may be, for example, but not limited to 0.0001%, 0.001%, 0.01% or 0.05%.

[0030] The tin brass alloy strip provided by the present invention is based on the Cu-Sn-Zn ternary alloy, and Ni, P and Mg elements are added. A small amount of Mg can refine the grains and improve the mechanical properties and bending properties of the material; the Ni element can make the material have a better work hardening effect, and at the same time, a trace amount of P element is added to form a Ni3P precipitation phase, which has a certain solid solution aging strengthening effect, and helps to further improve the mechanical properties and electrical conductivity of the material. The tensile strength of the tin brass alloy strip is 460-550MPa, and the elongation after fracture A 50 ≥7%, hardness HV145-165, conductivity ≥35% IACS, which can meet the requirements of connectors, plug terminals, etc. for material strength and conductivity.

[0031] In addition, the present invention does not add cobalt element. On the one hand, cobalt has a high melting point and requires a higher smelting temperature, which increases the difficulty and cost of smelting. On the other hand, Co resources are scarce and the price is relatively high.

[0032] In some optional embodiments, the tin-brass alloy strip has a thickness of 0.3-1.5 mm and a width of ≥600 mm.

[0033] In a second aspect, the present invention provides a method for preparing the above-mentioned tin brass alloy strip, comprising the following steps:

[0034] The materials are prepared according to the mass percentage, and then smelting, casting, hot rolling, milling, the first cold rolling, the first recrystallization annealing, the second cold rolling, the second recrystallization annealing, the third cold rolling and low-temperature annealing are carried out in sequence to prepare a tin-brass alloy strip.

[0035] The preparation method provided by the present invention adopts a combined process of "high processing rate + low temperature recrystallization heat treatment + low temperature tempering of finished product", wherein the high processing rate process can effectively break and elongate the original coarse grains to form smaller grains, increase the dislocation density, and help improve the strength and flexibility of the material; combined with the low temperature recrystallization heat treatment, on the one hand, it can effectively eliminate the residual stress generated in the high processing rate cold deformation, and on the other hand, it can effectively prevent the growth of grains and improve the bending performance of the material; compared with the solution of adding Co, a lower recrystallization temperature is adopted, the grains are finer, and the performance similar to that of adding Co can be achieved, while the electroplating performance is better and the cost is lower; the low temperature annealing of the finished product is mainly for the purpose of eliminating residual stress and improving the poor stamping distortion, while at the same time improving the toughness of the material and making it easier to process the material.

[0036] In some optional embodiments, the smelting temperature may be, for example, but not limited to, 1200° C., 1210° C. or 1220° C.;

[0037] The casting process parameters include: the casting temperature can be, but not limited to, 1190°C, 1200°C or 1210°C; the initial casting speed is 60±5mm / min, the normal casting speed is 95±5mm / min, the initial cooling water flow rate is 50-60m 3 / h, normal cooling water flow rate 65~75m 3 / h.

[0038] In some optional embodiments, the ingot has a width ≥ 610 mm and a thickness ≥ 180 mm.

[0039] In some optional embodiments, the ingot is heated in a walking furnace at a temperature ranging from 900 to 1000° C. at a rate of 10 to 12° C. / min, and then hot-rolled;

[0040] The hot rolling start temperature may be, for example, but not limited to, 800° C., 830° C. or 850° C.;

[0041] The final rolling temperature of the hot rolling may be, for example, but not limited to, 450° C., 480° C. or 500° C.;

[0042] The total processing rate of the hot rolling may be, for example, but not limited to, 90%, 93% or 95%.

[0043] In some optional embodiments, the processing rate of the first cold rolling may be, for example, but not limited to, 80%, 83% or 85%;

[0044] The processing rate of the second cold rolling may be, for example, but not limited to, 40%, 45% or 50%;

[0045] The third cold rolling is performed to the finished product specification thickness.

[0046] In some optional embodiments, the first recrystallization annealing is an intermediate annealing treatment, the annealing temperature may be, but not limited to, 400°C, 410°C or 420°C, and the holding time may be, but not limited to, 4h, 5h or 6h.

[0047] In some optional embodiments, the second recrystallization annealing is a bell jar annealing treatment, the annealing temperature may be, for example, but not limited to 380° C., 390° C. or 400° C., and the holding time may be, for example, but not limited to 4 h, 5 h or 6 h.

[0048] In some optional embodiments, the first recrystallization annealing and the second recrystallization annealing are performed under a protective atmosphere.

[0049] Copper strips need to be processed by stamping, bending and other processes before they can be used as parts, which requires the strips to have certain bending and stretching properties. The present invention adopts three cold rolling and two low-temperature recrystallization annealing, and through a multi-stage integrated deformation heat treatment process, the alloy structure is regulated to obtain a structure with very fine grains, thereby achieving the purpose of improving the strength and bending properties of the strip.

[0050] In some optional embodiments, the annealing temperature of the low-temperature annealing treatment may be, for example, but not limited to, 210° C., 230° C. or 260° C., and the holding time may be, for example, but not limited to, 2 h, 3 h or 5 h.

[0051] During stamping, bending and other processing, the strip undergoes plastic deformation. The essence of plastic deformation is the slip of dislocations, and the accumulation of a large number of dislocation slips forms macroscopic deformation. Copper alloy strips are composed of polycrystalline, and the plastic deformation properties of grains with different orientations are different, which is related to the Schmidt factor of the alloy. The Schmidt factor is calculated by the formula cosφ×cosλ, where φ is the angle between the external force direction and the slip plane, λ is the angle between the external force direction and the slip direction, and satisfies the relationship φ+λ≥90°. The larger the Schmidt factor, the easier it is to start the slip of dislocations, and the better the plastic deformation ability of the material. When φ+λ=90°, the Schmidt factor has a maximum value of 0.5. The present invention eliminates the adverse effects of surface texture on plastic deformation through processes such as rolling and low-temperature annealing, controls the Schmidt factor on the surface of the strip, and makes the Schmidt factor of more than 98% of the surface area greater than 0.3, thereby improving the plastic deformation ability of the material and preventing cracking during processing.

[0052] In a third aspect, the present invention provides a use of the above-mentioned tin-brass alloy strip in the preparation of a connector.

[0053] The tin brass alloy strip provided by the present invention has a tensile strength of 460-550 MPa and a post-fracture elongation A 50 ≥7%, hardness HV145-165, conductivity ≥35% IACS, which can meet the requirements of connectors, plug terminals, etc. for material strength and conductivity.

[0054] The present invention is further described below by means of specific examples and comparative examples. However, it should be understood that these examples are only used for more detailed description and should not be construed as limiting the present invention in any form.

[0055] Embodiment 1:

[0056] The alloy components of the invention are calculated by weight percentage as Cu: 90%, Ni: 0.2%, Sn: 0.3%, P: 0.005%, Mg: 0.01%, and the balance is Zn. The raw materials are electrolytic copper, 10% Cu-P master alloy, electrolytic nickel, tin ingot, zinc ingot, and 10% Cu-Mg master alloy.

[0057] Melting and casting: weigh the raw materials according to the alloy composition ratio, mix them and then melt and cast them in sequence. The melting temperature is 1200℃, the casting temperature is 1190℃, the initial casting speed is 60mm / min, the normal casting speed is 90mm / min, and the initial cooling water flow is 50m 3 / h, normal cooling water flow rate 65m 3 / h, processed into ingots;

[0058] Hot rolling: the ingot is heated in a walking furnace at a heating temperature of 900°C and a rate of 11°C / min. The hot rolling furnace temperature is 810°C, the total processing rate is 90%, and the final rolling temperature is 480°C.

[0059] Milling: During the hot rolling process, the surface of the alloy plate is severely oxidized. Double-sided milling is used to remove the oxide. The milling cutter speed is 700rpm, the machine speed is 10m / min, and the milling is performed once, with 0.5mm milling on the top and bottom.

[0060] Primary cold rolling: cold rolling the alloy sheet after milling, with a cold rolling processing rate of 80%, and multiple rolling passes to finally obtain the target thickness;

[0061] Recrystallization annealing: The coil after the first cold rolling is subjected to intermediate annealing treatment, the annealing temperature is 400℃, the temperature is kept for 5h, the annealing atmosphere is 75% H2+25% N2, and the cooling method is furnace cooling;

[0062] Secondary cold rolling: The alloy strip after intermediate annealing is subjected to secondary cold rolling, and the cold rolling processing rate is 40%;

[0063] Recrystallization annealing: The alloy strip after secondary cold rolling is placed in a bell-type annealing furnace for annealing at a temperature of 380°C for 5 hours in an atmosphere of 775% H2+25% N2, and the cooling method is furnace cooling;

[0064] Three cold rolling: rolling the remaining material to the finished product specification thickness;

[0065] Low temperature annealing: The three-time cold-rolled coils are subjected to low temperature annealing at a temperature of 230°C for 3.5 hours. The cooling method is furnace cooling.

[0066] Embodiment 2:

[0067] The alloy components of the invention are calculated by weight percentage as Cu: 90.5%, Ni: 0.3%, Sn: 0.38%, P: 0.0001%, Mg: 0.0001%, and the balance is Zn. The raw materials are electrolytic copper, 10% Cu-P master alloy, electrolytic nickel, tin ingot, zinc ingot, and 10% Cu-Mg master alloy.

[0068] Melting and casting: weigh the raw materials according to the alloy composition ratio, mix them and then melt and cast them in sequence. The melting temperature is 1205℃, the casting temperature is 1195℃, the initial casting speed is 62mm / min, the normal casting speed is 93mm / min, and the initial cooling water flow is 53m 3 / h, normal cooling water flow rate 67m 3 / h, processed into ingots;

[0069] Hot rolling: the ingot is heated in a walking furnace at a heating temperature of 930°C, a rate of 10°C / min, a hot rolling furnace temperature of 800°C, a total processing rate of 93%, and a final rolling temperature of 450°C;

[0070] Milling: During the hot rolling process, the surface of the alloy plate is severely oxidized. Double-sided milling is used to remove the oxide. The milling cutter speed is 650rpm, the machine speed is 13m / min, and the milling is performed once, with each milling 0.55mm;

[0071] Primary cold rolling: cold rolling the milled alloy sheet with a cold rolling rate of 81% and multiple rolling passes to finally obtain the target thickness;

[0072] Recrystallization annealing: The coil after the first cold rolling is subjected to intermediate annealing treatment, the annealing temperature is 405°C, the temperature is kept for 5.5h, the annealing atmosphere is 75% H2+25% N2, and the cooling method is furnace cooling;

[0073] Secondary cold rolling: the alloy strip after intermediate annealing is subjected to secondary cold rolling, and the cold rolling processing rate is 46%;

[0074] Recrystallization annealing: The alloy strip after secondary cold rolling is placed in a bell-type annealing furnace for annealing at a temperature of 385°C for 4 hours in a 75% H2+25% N2 atmosphere, and the cooling method is furnace cooling;

[0075] Three cold rolling: rolling the remaining material to the finished product specification thickness;

[0076] Low temperature annealing: The three-time cold-rolled coils are subjected to low temperature annealing at a temperature of 210°C for 2 hours, and the cooling method is furnace cooling.

[0077] Embodiment 3:

[0078] The alloy components of the present invention are calculated by weight percentage as Cu: 91%, Ni: 0.4%, Sn: 0.4%, P: 0.008%, Mg: 0.03%, and the balance is Zn. The raw materials are electrolytic copper, 10% Cu-P master alloy, electrolytic nickel, tin ingot, zinc ingot, and 10% Cu-Mg master alloy.

[0079] Melting and casting: weigh the raw materials according to the alloy composition ratio, mix them and then melt and cast them in sequence. The melting temperature is 1210℃, the casting temperature is 1200℃, the initial casting speed is 65mm / min, the normal casting speed is 95mm / min, and the initial cooling water flow is 54m 3 / h, normal cooling water flow rate 69m 3 / h, processed into ingots;

[0080] Hot rolling: the ingot is heated in a walking furnace at a heating temperature of 940°C and a rate of 10.5°C / min. The hot rolling furnace temperature is 830°C, the total processing rate is 91%, and the final rolling temperature is 460°C.

[0081] Milling: During the hot rolling process, the surface of the alloy plate is severely oxidized. Double-sided milling is used to remove the oxide. The milling cutter speed is 680rpm, the machine speed is 12m / min, and the milling is performed once, with 0.6mm milling on the top and bottom.

[0082] Primary cold rolling: cold rolling the milled alloy sheet with a cold rolling rate of 82% and multiple rolling passes to finally obtain the target thickness;

[0083] Recrystallization annealing: The coil after the first cold rolling is subjected to intermediate annealing treatment, the annealing temperature is 410℃, the temperature is kept for 4.5h, the annealing atmosphere is 75% H2+25% N2, and the cooling method is furnace cooling;

[0084] Secondary cold rolling: the alloy strip after intermediate annealing is subjected to secondary cold rolling, and the cold rolling processing rate is 48%;

[0085] Recrystallization annealing: The alloy strip after secondary cold rolling is placed in a bell-type annealing furnace for annealing at a temperature of 390°C for 4.5 hours in a 75% H2+25% N2 atmosphere, and the cooling method is furnace cooling;

[0086] Three cold rolling: rolling the remaining material to the finished product specification thickness;

[0087] Low temperature annealing: The three-time cold-rolled coils are subjected to low temperature annealing at a temperature of 240°C for 3 hours, and the cooling method is furnace cooling.

[0088] Embodiment 4:

[0089] The alloy components of the invention are calculated by weight percentage as Cu: 91.5%, Ni: 0.6%, Sn: 0.45%, P: 0.009%, Mg: 0.04%, and the balance is Zn. The raw materials are electrolytic copper, 10% Cu-P master alloy, electrolytic nickel, tin ingot, zinc ingot, and 10% Cu-Mg master alloy.

[0090] Melting and casting: weigh the raw materials according to the alloy composition ratio, mix them and then melt and cast them in sequence. The melting temperature is 1215℃, the casting temperature is 1205℃, the initial casting speed is 55mm / min, the normal casting speed is 98mm / min, and the initial cooling water flow is 55m 3 / h, normal cooling water flow rate 70m 3 / h, processed into ingots;

[0091] Hot rolling: the ingot is heated in a walking furnace at a heating temperature of 980°C and a rate of 11.5°C / min. The hot rolling furnace temperature is 840°C, the total processing rate is 94%, and the final rolling temperature is 490°C.

[0092] Milling: During the hot rolling process, the surface of the alloy plate is severely oxidized. Double-sided milling is used to remove the oxide. The milling cutter speed is 800rpm, the machine speed is 11m / min, and the milling is performed once, with each milling 0.7mm;

[0093] Primary cold rolling: cold rolling the alloy sheet after milling, with a cold rolling processing rate of 83%, and multiple rolling passes to finally obtain the target thickness;

[0094] Recrystallization annealing: The coil after the first cold rolling is subjected to intermediate annealing treatment, the annealing temperature is 415°C, the heat preservation time is 4.0h, the annealing atmosphere is 75% H2+25% N2, and the cooling method is furnace cooling;

[0095] Secondary cold rolling: The alloy strip after intermediate annealing is subjected to secondary cold rolling, and the cold rolling processing rate is 49%;

[0096] Recrystallization annealing: The alloy strip after secondary cold rolling is placed in a bell-type annealing furnace for annealing at a temperature of 395°C for 5.5 hours in a 75% H2+25% N2 atmosphere, and the cooling method is furnace cooling;

[0097] Three cold rolling: rolling the remaining material to the finished product specification thickness;

[0098] Low temperature annealing: The three-time cold-rolled coils are subjected to low temperature annealing at a temperature of 250°C for 4 hours, and the cooling method is furnace cooling.

[0099] Embodiment 5:

[0100] The alloy components of the invention are calculated by weight percentage as Cu: 92%, Ni: 0.8%, Sn: 0.5%, P: 0.01%, Mg: 0.05%, and the balance is Zn. The raw materials are electrolytic copper, 10% Cu-P master alloy, electrolytic nickel, tin ingot, zinc ingot, and 10% Cu-Mg master alloy.

[0101] Melting and casting: weigh the raw materials according to the alloy composition ratio, mix them and then melt and cast them in sequence. The melting temperature is 1220℃, the casting temperature is 1210℃, the initial casting speed is 58mm / min, the normal casting speed is 100mm / min, and the initial cooling water flow is 58m 3 / h, normal cooling water flow rate 75m 3 / h, processed into ingots;

[0102] Hot rolling: the ingot is heated in a walking furnace at a heating temperature of 995°C, a rate of 12°C / min, a hot rolling furnace temperature of 850°C, a total processing rate of 95%, and a final rolling temperature of 500°C;

[0103] Milling: During the hot rolling process, the surface of the alloy plate is severely oxidized. Double-sided milling is used to remove the oxide. The milling cutter speed is 850rpm, the machine speed is 15m / min, and the milling is performed once, with each milling 0.8mm;

[0104] Primary cold rolling: cold rolling the milled alloy sheet with a cold rolling rate of 85% and multiple rolling passes to finally obtain the target thickness;

[0105] Recrystallization annealing: The coil after the first cold rolling is subjected to intermediate annealing treatment, the annealing temperature is 420℃, the temperature is kept for 6.0h, the annealing atmosphere is 75% H2+25% N2, and the cooling method is furnace cooling;

[0106] Secondary cold rolling: The alloy strip after intermediate annealing is subjected to secondary cold rolling, and the cold rolling processing rate is 50%;

[0107] Recrystallization annealing: The alloy strip after secondary cold rolling is placed in a bell-type annealing furnace for annealing at a temperature of 400°C for 6 hours in a 75% H2+25% N2 atmosphere, and the cooling method is furnace cooling;

[0108] Three cold rolling: rolling the remaining material to the finished product specification thickness;

[0109] Low temperature annealing: The three-time cold-rolled coils are subjected to low temperature annealing at 260°C for 5 hours, and the cooling method is furnace cooling.

[0110] Comparative Example 1:

[0111] The difference from Example 1 is that no Ni element is added.

[0112] Comparative Example 2:

[0113] The difference from Example 1 is that no P element is added.

[0114] Comparative Example 3:

[0115] The difference from Example 1 is that no Mg element is added.

[0116] Comparative Example 4:

[0117] The difference from Example 1 is that there is no low-temperature annealing of the finished product.

[0118] Comparative Example 5:

[0119] The difference from Example 1 is that the low-temperature annealing temperature of the finished product is 280°C.

[0120] Comparative Example 6:

[0121] The difference from Example 1 is that the secondary cold rolling directly rolls the remaining stock to the finished product thickness, without secondary recrystallization annealing and the third cold rolling.

[0122] Comparative Example 7

[0123] The difference from Example 1 is that 1.02% of Co is added, the first recrystallization temperature is 530°C, and the second recrystallization temperature is 420°C.

[0124] The properties of the strips provided in the above embodiments and comparative examples were tested respectively, and the results are shown in Table 1.

[0125] Table 1

[0126]

[0127]

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A tin-brass alloy strip, characterized in that: Calculated by mass percentage, it includes: Cu 90% to 92%, Ni 0.2% to 0.8%, Sn 0.3% to 0.5%, P 0.0001% to 0.01%, Mg 0.0001% to 0.05%, and the balance is Zn.

2. The method for preparing the tin-brass alloy strip according to claim 1, characterized in that: The following steps are involved: The materials are prepared according to the mass percentage, and then smelting, casting, hot rolling, milling, the first cold rolling, the first recrystallization annealing, the second cold rolling, the second recrystallization annealing, the third cold rolling and low-temperature annealing are carried out in sequence to prepare a tin-brass alloy strip.

3. The preparation method according to claim 2, characterized in that: The smelting temperature is 1200-1220°C; The casting process parameters include: a casting temperature of 1190-1210° C., a casting speed of 55-95 mm / min, and a cooling water flow rate of 50-75 cubic meters / hour.

4. The preparation method according to claim 2, characterized in that: The hot rolling start temperature is 800-850°C; The final rolling temperature of the hot rolling is 450-500°C; The total processing rate of the hot rolling is 90% to 95%.

5. The preparation method according to claim 2, characterized in that: The processing rate of the first cold rolling is 80% to 85%; The processing rate of the second cold rolling is 40% to 50%; The third cold rolling is performed to the finished product specification thickness.

6. The preparation method according to claim 2, characterized in that: The first recrystallization annealing is an intermediate annealing treatment, the annealing temperature is 400-420° C., and the holding time is 4-6 hours.

7. The preparation method according to claim 2, characterized in that: The second recrystallization annealing is a bell jar annealing treatment, the annealing temperature is 380-400° C., and the holding time is 4-6 hours.

8. The preparation method according to claim 2, characterized in that: The first recrystallization annealing and the second recrystallization annealing are performed under a protective atmosphere.

9. The preparation method according to claim 2, characterized in that: The annealing temperature of the low-temperature annealing treatment is 210-260° C., and the insulation time is 2-5 hours.

10. Use of the tin-brass alloy strip according to claim 1 in preparing connectors.

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