A BZN15-20 zinc-nickel copper strip and production method thereof

Abstract

The present invention provides a BZN15‑20 zinc-nickel copper strip and a production method thereof, comprising: Cu 62.4‑64.8%, Fe 0.15‑0.20%, Ni 13.8‑15.5%, Pb≤0.01%, and Zn as the remainder. Compared with the prior art, the present invention reduces the coiling cycle by 32 hours per time; the production process of the present invention reduces the processing cost; and the high-temperature annealing control combined with the three annealings improves the ductility of the product. The production method of the present invention can gradually expand the foreign zinc-nickel copper market, and the processing cost is lower than that of foreign zinc-nickel copper C7701 / C7521 copper. The product of the present invention has excellent performance, and the tensile strength is ≥410N / mm 2 , yield strength ≥305N / mm 2 , elongation ≥ 40%, Vickers hardness ≥ 95HV, to enhance the application of nickel silver materials in products with high ductility.

Description

Technical Field

[0001] The invention belongs to the field of copper alloy production, and in particular relates to a BZN15-20 zinc-white copper strip and a production method thereof. Background Art

[0002] With the gradual improvement of technology, Bzn18-26 zinc white copper (C7701) and Bzn18-18 zinc white copper (C7521) are commonly used in the market, while Bzn15-20 zinc white copper is a copper alloy containing about 18-24% zinc and 13.5%-16.5% nickel, with good strength and corrosion resistance. Bzn15-20 zinc white copper is mainly due to the high market price of copper alloys and the evolution of enterprises to reduce costs. This alloy is often used to manufacture electrical contacts, bearings, airtight containers and other parts. Its technical research mainly involves the preparation process, heat treatment process and performance testing of the alloy.

[0003] Bzn15-20 is usually used to manufacture electrical contactors and switches, electrical sockets, electrical terminals, engine parts and other parts that require high conductivity and corrosion resistance. It has good electrical conductivity: Due to the large amount of copper and a small amount of zinc, Bzn15-20 zinc white copper has good electrical conductivity, so it is suitable for manufacturing electrical parts. It also has corrosion resistance: zinc white copper has good corrosion resistance at room temperature and can resist the erosion of most chemical media, which allows it to maintain stable performance in humid and corrosive environments. It also has good processing performance: Bzn15-20 zinc white copper has good processing performance, can be cold processed, hot processed and welded, and can meet the manufacturing requirements of complex parts. The thermal conductivity is also good: zinc white copper has good thermal conductivity and can effectively dissipate heat, so it is suitable for manufacturing parts that require heat dissipation.

[0004] In summary, Bzn15-20 zinc white copper has good electrical conductivity, corrosion resistance, processing performance and thermal conductivity. It is suitable for manufacturing a variety of electrical and mechanical parts and has broad application prospects in the industrial field.

[0005] However, Bzn15-20 zinc white copper is scarce in domestic and foreign markets. The basic standard grades are Bzn18-26 zinc white copper (C7701) and Bzn18-18 zinc white copper (C7521), while Bzn15-20 zinc white copper (C7541) is rarely circulated in the market. Since the application demand generally relies on imports and there is a demand for Bzn15-20 zinc white copper (C7541), it is scarce at home and abroad. Domestic enterprises generally produce standard grades with large consumption, and produce very little Bzn15-20 zinc white copper (C7541). Summary of the invention

[0006] The object of the present invention is to provide a BZN15-20 zinc-nickel copper strip and a production method thereof, and to reduce the production time of each roll, reduce the processing cost, and improve the ductility of the product through a designed production process.

[0007] The specific technical solutions of the present invention are as follows:

[0008] The present invention provides a BZN15-20 zinc-nickel copper strip, wherein the BZN15-20 zinc-nickel copper strip comprises the following components in percentage by mass:

[0009] Cu 62.2-64.8%, Fe 0.15-0.20%, Ni 13.8-15.5%, Pb≤0.01%, Zn is the balance. The tensile strength of the BZN15-20 zinc-nickel copper strip is ≥410N / mm 2 , yield strength

[0010] ≥305N / mm 2 , elongation ≥40%, Vickers hardness ≥95HV.

[0011] A method for producing BZN15-20 zinc-nickel copper strip comprises the following process flow:

[0012] 1) Melting;

[0013] 2) Casting;

[0014] 3) Milling;

[0015] 4) Rough rolling;

[0016] 5) trimming;

[0017] 6) primary annealing;

[0018] 7) Thick belt cleaning;

[0019] 8) Intermediate rolling products;

[0020] 9) Secondary annealing;

[0021] 10) Three annealings;

[0022] 11) Thin strip cleaning;

[0023] 12) Pulling a little;

[0024] 13) Divide into strips.

[0025] The smelting described in step 1) is specifically as follows: electrolytic copper (old material) - tin - charcoal - melting - heating - melting - phosphor copper alloy - heating - stirring and slag removal - sampling and analysis - charcoal - heating converter 1220-1225°C.

[0026] The casting described in step 2) is T16×440mm, and the equipment used is horizontal continuous casting; the casting process is pull-stop-reverse push, the casting speed is 134mm / min, stop 1-1.5s, and reverse push 2.5mm.

[0027] Step 3) The milling surface is milled using a milling machine, and the milling surface is T14×436mm; specifically: the upper surface is 1.0mm, the lower surface is 1.0mm, the left side is 2mm, and the right side is 2mm;

[0028] Step 4) Rough rolling, using a rough rolling mill, rough rolling 1.0×436mm; specifically, a four-roll rolling mill is used to open the blank and roll the copper strip to 1.0×436mm in multiple passes. During rolling, an emulsion is used as a lubricant and coolant at a speed of 200-300m / min.

[0029] Step 5) trimming, using a thick slitting machine, after trimming 436mm, the size is 415mm;

[0030] Step 6) primary annealing, using a bell-shaped furnace for annealing, the annealing temperature is 600-680° C., the heating time is 6-8 hours, and the heat preservation time is 8-10 hours.

[0031] Step 7) thick strip cleaning: a thick strip cleaning machine is used to process the copper strip through alkaline degreasing, acid washing to remove the oxide layer, and other cleaning processes, with a cleaning speed of 40-60 m / min.

[0032] Step 8) intermediate rolling of the finished product; using an intermediate finishing mill size: 0.5×415mm; specifically: the cleaned copper strip is processed through a four-roll mill for multiple passes, the rolling thickness is 0.5mm, the roughness of the roller is controlled at 0.15-0.18μm, the rolling is fully oiled, and the rolling speed is controlled at 150-180m / min.

[0033] Step 9) Secondary annealing, using a controlled continuous atmosphere annealing furnace, the furnace temperature is 700-800℃, the atmosphere is N 2 Content 98%-99%+H 2 Content 1%-1.8%, trace amounts of other atmospheres, annealing speed 13-17m / min, the control coefficient ratio of the present invention is unwinding section tension coefficient: inlet looper tension coefficient: furnace zone tension coefficient: braking zone tension coefficient: outlet looper tension coefficient: grinding brush zone tension coefficient: winding section tension coefficient = 12:11:2.4:11:11:13:20, heating zone fan speed: 1100rpm, hot and cold zone fan speed: 1100rpm.

[0034] Step 10) annealing three times, using a bell-shaped furnace, annealing temperature of 440-480°C, heating time: 4-6 hours, and insulation time of 5-8 hours.

[0035] Step 9) and step 10) are coordinated, and high temperature annealing control is combined with three annealings to improve the ductility of white copper.

[0036] Step 11) Strip cleaning: using a strip cleaning machine, the copper strip is subjected to alkaline degreasing, pickling to remove the oxide layer, polishing, and spray passivation processes, with a cleaning speed of 40-60 m / min.

[0037] Step 12) Straightening, using a straightening machine, speed 150m / min, plate shape <5I.

[0038] Step 13) Slitting: Slitting is performed using a thin longitudinal shearing machine.

[0039] The existing technology has a long production cycle. Compared with the existing technology, the present invention reduces the coiling cycle by 32 hours (the bell furnace used for the production of the finished product requires a long insulation time of at least 32 hours to soften the material. The present invention uses an air cushion furnace to greatly reduce the annealing time). The production process of the present invention reduces the processing cost and improves the ductility of the product. The production method of the present invention can gradually expand the foreign zinc-nickel copper market, and the processing cost is lower than that of foreign zinc-nickel copper C7701 / C7521 copper. Improve the application of nickel-nickel copper materials in products with high ductility. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 This is the Cu-Ni-Zn grain image of Comparative Example 1 at 100 times magnification;

[0041] Figure 2 This is the Cu-Ni-Zn grain image of Comparative Example 1 at 200 times magnification;

[0042] Figure 3 This is a Cu-Ni-Zn grain map of Example 1 at 100 times magnification;

[0043] Figure 4 This is the Cu-Ni-Zn grain map of Example 1 at 200 times magnification. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] The following specific embodiments and comparative examples will be described based on a Bzn15-20 zinc-nickel copper strip (C7541) having a finished thickness of 0.5 mm and being in a soft state.

[0046] Example 1

[0047] A BZN15-20 zinc-nickel copper strip includes the following components in mass percentage: as shown in Table 1.

[0048] The production method of the BZN15-20 zinc-nickel copper strip described in Example 1 comprises the following steps:

[0049] 1) Smelting: electrolytic copper (old material) - tin - charcoal - melting - heating - melting - phosphorus copper alloy - heating - stirring and slag removal - sampling and analysis - charcoal - heating converter 1220-1225℃.

[0050] 2) Casting: pull-stop-reverse push process, casting speed 134mm / min, stop 1.5S, reverse push 2.5mm;

[0051] 3) Milling surface: upper surface 1.0mm, lower surface 1.0mm, left side 2mm, right side 2mm;

[0052] 4) Rough rolling: A four-roll rolling mill is used to open the blank and roll the copper strip to 1.0 mm in multiple passes. During rolling, an emulsion is used as a lubricant and coolant at a speed of 300 m / min.

[0053] 5) Thick longitudinal shearing: 436mm, cutting edge 415mm.

[0054] 6) Primary annealing: annealing temperature is 670°C, heating time is 6.4 hours, and holding time is 9 hours.

[0055] 7) Thick strip cleaning: The copper strip is subjected to alkaline degreasing, acid washing to remove the oxide layer and other cleaning processes, with a cleaning speed of 45m / min.

[0056] 8) Intermediate rolling and finishing rolling: The cleaned copper strip is processed through a four-roll rolling mill for multiple passes, the rolling thickness is 0.5 mm, the roughness of the roller is controlled at 0.15 μm, the rolling is fully oiled, and the rolling speed is controlled at 170 m / min.

[0057] 9) Secondary annealing: Use a controlled continuous atmosphere annealing furnace with a furnace temperature of 780°C and an atmosphere of N 2 Content 99%+H 2 Content 1%, annealing speed 15m / min, tension ratio: unwinding section tension coefficient: entrance looper tension coefficient: furnace area tension coefficient: braking area tension coefficient: exit looper tension coefficient: grinding brush area tension coefficient: winding section tension coefficient = 12:11:2.4:11:11:13:20, heating zone fan speed: 1100rpm, hot and cold zone fan speed: 1100rpm.

[0058] 10) Three annealing: annealing temperature is 460°C, heating time is 4.7 hours, and holding time is 5 hours.

[0059] 11) Cleaning: The copper strip is subjected to alkaline degreasing, pickling to remove the oxide layer, polishing, and spray passivation processes, with a cleaning speed of 45 m / min.

[0060] 12) Pulling: speed 150m / min, board type <5I.

[0061] 13) Divide into strips.

[0062] Example 2

[0063] A BZN15-20 zinc-nickel copper strip includes the following components in mass percentage: as shown in Table 1.

[0064] The production method of the BZN15-20 zinc-nickel copper strip described in Example 2 comprises the following steps:

[0065] 1) Smelting: electrolytic copper (old material) - tin - charcoal - melting - heating - melting - phosphorus copper alloy - heating - stirring and slag removal - sampling and analysis - charcoal - heating converter 1220-1225℃.

[0066] 2) Casting: pull-stop-reverse push process, casting speed 134mm / min, stop 1S, reverse push 2.5mm;

[0067] 3) Milling surface: upper surface 1.0mm lower surface 1.0mm left 2mm right 2mm;

[0068] 4) Rough rolling: A four-roll rolling mill is used to open the blank and roll the copper strip to 1.0 mm in multiple passes. During rolling, an emulsion is used as a lubricant and coolant at a speed of 300 m / min.

[0069] 5) Thick longitudinal shearing: 436mm, cutting edge 415mm.

[0070] 6) Primary annealing: annealing temperature is 670°C, heating time is 6.4 hours, and holding time is 9 hours.

[0071] 7) Thick strip cleaning: The copper strip is subjected to alkaline degreasing, acid washing to remove the oxide layer and other cleaning processes, with a cleaning speed of 60m / min.

[0072] 8) Intermediate rolling and finishing rolling: The cleaned copper strip is processed through a four-roll rolling mill for multiple passes, the rolling thickness is 0.5 mm, the roughness of the roller is controlled at 0.16 μm, the rolling is fully oiled, and the rolling speed is controlled at 180 m / min.

[0073] 9) Secondary annealing (controlled continuous atmosphere annealing furnace): furnace temperature 780°C, atmosphere N 2 Content 99%+H 2Content 1%, annealing speed 17m / min, tension ratio: uncoiling section tension coefficient: entrance looper tension coefficient: furnace area tension coefficient: braking area tension coefficient: exit looper tension coefficient: grinding brush area tension coefficient: winding section tension coefficient = 12:11:2.4:11:11:13:20, heating zone fan speed: 1100rpm, hot and cold zone fan speed: 1100rpm.

[0074] 10) Three annealing: annealing temperature is 440°C, heating time is 4.1 hours, and holding time is 5 hours;

[0075] 11) Cleaning: The copper strip is subjected to alkaline degreasing, pickling to remove the oxide layer, polishing, and spray passivation processes, with a cleaning speed of 60m / min.

[0076] 12) Pulling: speed 150m / min, board type <5I.

[0077] 13) Divide into strips.

[0078] Example 3

[0079] A BZN15-20 zinc-nickel copper strip includes the following components in mass percentage: as shown in Table 1.

[0080] The production method of the BZN15-20 zinc-nickel copper strip described in Example 3 comprises the following steps:

[0081] 1) Smelting: electrolytic copper (old material) - tin - charcoal - melting - heating - melting - phosphorus copper alloy - heating - stirring and slag removal - sampling and analysis - charcoal - heating converter 1220-1225℃.

[0082] 2) Casting: pull-stop-reverse push process, casting speed 134mm / min, stop 1.5S, reverse push 2.5mm;

[0083] 3) Milling surface: upper surface 1.0mm lower surface 1.0mm left 2mm right 2mm;

[0084] 4) Rough rolling: A four-roll rolling mill is used to open the blank and roll the copper strip to 1.0 mm in multiple passes. During rolling, an emulsion is used as a lubricant and coolant at a speed of 250 m / min.

[0085] 5) Thick longitudinal shearing: 436mm, cutting edge 415mm.

[0086] 6) Primary annealing: annealing temperature is 670°C, heating time is 6.4 hours, and holding time is 9 hours.

[0087] 7) Thick strip cleaning: The copper strip is subjected to alkaline degreasing, acid washing to remove the oxide layer and other cleaning processes, with a cleaning speed of 50m / min.

[0088] 8) Intermediate rolling and finishing rolling: The cleaned copper strip is processed through a four-roll rolling mill for multiple passes, the rolling thickness is 0.5 mm, and the roughness of the roller is controlled at 0.18 μm; the rolling is carried out using full oil rolling, and the rolling speed is controlled at 180 m / min.

[0089] 9) Secondary annealing (controlled continuous atmosphere annealing furnace): furnace temperature 800°C, atmosphere N 2 Content 99%+H 2 Content 1%, annealing speed 13m / min, tension ratio: unwinding section tension coefficient: entrance looper tension coefficient: furnace area tension coefficient: braking area tension coefficient: exit looper tension coefficient: grinding brush area tension coefficient: winding section tension coefficient = 12:11:2.4:11:11:13:20, heating zone fan speed: 1100rpm, hot and cold zone fan speed: 1100rpm.

[0090] 10) Three annealing: annealing temperature is 480°C, heating time is 4.7 hours, and holding time is 5 hours;

[0091] 11) Cleaning: The copper strip is subjected to alkaline degreasing, pickling to remove the oxide layer, polishing, and spray passivation processes, with a cleaning speed of 50 m / min.

[0092] 12) Pulling: speed 150m / min, board type <5I.

[0093] 13) Divide into strips.

[0094] Comparative Example 1

[0095] A BZN15-20 zinc-nickel copper strip includes the following components in mass percentage: as shown in Table 1.

[0096] The production method of the BZN15-20 zinc-nickel copper strip described in Comparative Example 1 comprises the following steps:

[0097] 1) Smelting: electrolytic copper (old material) - tin - charcoal - melting - heating - melting - phosphor copper alloy - heating - stirring and slag removal - sampling and analysis - charcoal - heating converter 1220-1225℃.

[0098] 2) Casting: pull-stop-reverse push process, casting speed 134mm / min, stop 1.5S, reverse push 2.5mm;

[0099] 3) Milling surface: upper surface 1.0mm lower surface 1.0mm left 2mm right 2mm;

[0100] 4) Rough rolling: A four-roll rolling mill is used to open the blank and roll the copper strip to 1.0 mm in multiple passes. During rolling, an emulsion is used as a lubricant and coolant at a speed of 300 m / min.

[0101] 5) Thick longitudinal shearing: 436mm, cutting edge 415mm.

[0102] 6) Primary annealing: annealing temperature is 670°C, heating time is 6.4 hours, and holding time is 9 hours.

[0103] 7) Thick strip cleaning: The copper strip is subjected to alkaline degreasing, acid washing to remove the oxide layer and other cleaning processes, with a cleaning speed of 45m / min.

[0104] 8) Intermediate rolling and finishing rolling: The cleaned copper strip is processed through a four-roll rolling mill for multiple passes, the rolling thickness is 0.5 mm, the roughness of the roller is controlled at 0.15 μm, the rolling is fully oiled, and the rolling speed is controlled at 170 m / min.

[0105] 9) Secondary annealing (controlled continuous atmosphere annealing furnace): furnace temperature 780°C, atmosphere N 2 Content 99%+H 2 Content 1%, annealing speed 15m / min, annealing speed 15m / min, tension ratio: uncoiling section tension coefficient: entrance looper tension coefficient: furnace area tension coefficient: braking area tension coefficient: exit looper tension coefficient: grinding brush area tension coefficient: winding section tension coefficient = 12:11:2.4:11:11:13:20, heating zone fan speed: 1100rpm, hot and cold zone fan speed: 1100rpm.

[0106] 10) Cleaning: The copper strip is subjected to alkaline degreasing, pickling to remove the oxide layer, polishing, and spray passivation processes, with a cleaning speed of 45 m / min.

[0107] 11) Pulling: speed 150m / min, board type <5I.

[0108] 12) Divide into strips.

[0109] Comparative Example 2

[0110] A BZN15-20 zinc-nickel copper strip includes the following components in mass percentage: as shown in Table 1.

[0111] The production method of the BZN15-20 zinc-nickel copper strip described in Comparative Example 2 comprises the following steps:

[0112] 1) Smelting: electrolytic copper (old material) - tin - charcoal - melting - heating - melting - phosphor copper alloy - heating - stirring and slag removal - sampling and analysis - charcoal - heating converter 1220-1225℃.

[0113] 2) Casting: pull-stop-reverse push process, casting speed 134mm / min, stop 1S, reverse push 2.5mm

[0114] 3) Milling surface: upper surface 1.0mm lower surface 1.0mm left 2mm right 2mm;

[0115] 4) Rough rolling: A four-roll rolling mill is used to open the blank and roll the copper strip to 1.0 mm in multiple passes. During rolling, an emulsion is used as a lubricant and coolant at a speed of 300 m / min.

[0116] 5) Thick longitudinal shearing: 436mm, cutting edge 415mm.

[0117] 6) Primary annealing: annealing temperature is 670°C, heating time is 6.4 hours, and holding time is 9 hours.

[0118] 7) Thick strip cleaning: The copper strip is subjected to alkaline degreasing, acid washing to remove the oxide layer and other cleaning processes, with a cleaning speed of 60m / min.

[0119] 8) Intermediate rolling and finishing rolling: The cleaned copper strip is processed through a four-roll rolling mill for multiple passes, the rolling thickness is 0.5 mm, the roughness of the roller is controlled at 0.16 μm, the rolling is fully oiled, and the rolling speed is controlled at 180 m / min.

[0120] 9) Secondary annealing (controlled continuous atmosphere annealing furnace): furnace temperature 780°C, atmosphere N 2 Content 99%+H 2 Content 1%, annealing speed 17m / min, tension ratio: unwinding section tension coefficient: entrance looper tension coefficient: furnace area tension coefficient: braking area tension coefficient: exit looper tension coefficient: grinding brush area tension coefficient: winding section tension coefficient = 12:11:2.4:11:11:13:20, heating zone fan speed: 1100rpm, hot and cold zone fan speed: 1100rpm.

[0121] 10) Cleaning: The copper strip is subjected to alkaline degreasing, pickling to remove the oxide layer, polishing, and spray passivation processes, with a cleaning speed of 60m / min.

[0122] 11) Pulling: speed 150m / min, board type <5I.

[0123] 12) Divide into strips.

[0124] Comparative Example 3

[0125] A BZN15-20 zinc-nickel copper strip includes the following components in mass percentage: as shown in Table 1.

[0126] The production method of the BZN15-20 zinc-nickel copper strip described in Comparative Example 3 comprises the following steps:

[0127] 1) Smelting: electrolytic copper (old material) - tin - charcoal - melting - heating - melting - phosphor copper alloy - heating - stirring and slag removal - sampling and analysis - charcoal - heating converter 1220-1225℃.

[0128] 2) Casting: pull-stop-reverse push process, casting speed 134mm / min, stop 1.5S, reverse push 2.5mm;

[0129] 3) Milling surface: upper surface 1.0mm lower surface 1.0mm left 2mm right 2mm;

[0130] 4) Rough rolling: A four-roll rolling mill is used to open the blank and roll the copper strip to 1.0 mm in multiple passes. During rolling, an emulsion is used as a lubricant and coolant at a speed of 250 m / min.

[0131] 5) Thick longitudinal shearing: 436mm, cutting edge 415mm.

[0132] 6) Primary annealing: annealing temperature is 670°C, heating time is 6.4 hours, and holding time is 9 hours.

[0133] 7) Thick strip cleaning: The copper strip is subjected to alkaline degreasing, acid washing to remove the oxide layer and other cleaning processes, with a cleaning speed of 50m / min.

[0134] 8) Intermediate rolling and finishing rolling: The cleaned copper strip is processed through a four-roll rolling mill for multiple passes, the rolling thickness is 0.5 mm, the roughness of the roller is controlled at 0.18 μm, the rolling is fully oiled, and the rolling speed is controlled at 150-180 m / min.

[0135] 9) Secondary annealing (controlled continuous atmosphere annealing furnace): furnace temperature 800°C, atmosphere N 2 Content 99%+H 2 Content 1%, annealing speed 13m / min, tension ratio: unwinding section tension coefficient: entrance looper tension coefficient: furnace area tension coefficient: braking area tension coefficient: exit looper tension coefficient: grinding brush area tension coefficient: winding section tension coefficient = 12:11:2.4:11:11:13:20, heating zone fan speed: 1100rpm, hot and cold zone fan speed: 1100rpm.

[0136] 10) Cleaning: The copper strip is subjected to alkaline degreasing, pickling to remove the oxide layer, polishing, and spray passivation processes, with a cleaning speed of 50 m / min.

[0137] 11) Pulling: speed 150m / min, board type <5I.

[0138] 12) Divide into strips.

[0139] Table 1 Composition and content of BZN15-20 zinc-nickel-copper strip in various embodiments and comparative examples (wt%)

[0140] Element Cu Fe Pb Ni Zn Example 1 62.5％ 0.16％ 0.008％ 14.1％ margin Example 2 62.7％ 0.18％ 0.009％ 13.9％ margin Example 3 62.5％ 0.15％ 0.009％ 14.1％ margin Comparative Example 1 62.3％ 0.15％ 0.008％ 13.8％ margin Comparative Example 2 62.5％ 0.17％ 0.008％ 13.5％ margin Comparative Example 3 62.5％ 0.2％ 0.008％ 14.3％ margin

[0141] The secondary and tertiary annealing parameters and properties of the embodiments and comparative examples are shown in Table 2, and the properties were tested according to GB / T2059-2000.

[0142] Table 2 Return parameters and performance of each embodiment and comparative example

[0143]

[0144] Although Comparative Examples 1 to 3 use alloys similar to those of the embodiment, they are not subjected to three annealings, resulting in reduced performance, especially ductility, which is significantly lower than that of the embodiment.

[0145] Figure 1 This is the Cu-Ni-Zn grain map of Comparative Example 1 at 100 times magnification. Figure 2 The Cu-Ni-Zn grain map of Comparative Example 1 at 200 times magnification is shown in FIG. Comparative Example 1 is subjected to secondary annealing in step 9. During the annealing process, recrystallization nucleation and grain growth are formed, and crystal defects such as dislocations inside the cupronickel migrate and rearrange. When the temperature reaches the recrystallization temperature, new non-distorted grains begin to nucleate and gradually grow, replacing the original deformed grains, thereby eliminating the work hardening phenomenon and restoring the plasticity of the material. During annealing, alloy elements such as nickel and zinc in the cupronickel diffuse in the lattice, making the element distribution gradually uniform and reducing component segregation.

[0146] Figure 3 This is the Cu-Ni-Zn grain map of Example 1 at 100 times magnification. Figure 4 This is a 200x Cu-Ni-Zn grain map of Example 1. The effects of the second annealing in step 9) and the third annealing in step 10) of the example are as follows:

[0147] Further grain refinement and uniformity: Based on the secondary annealing, the tertiary annealing will cause the grains to continue to change. The grains will be further refined and more uniform, which will help improve the comprehensive properties of the material, such as strength, toughness, ductility and corrosion resistance.

[0148] Changes in precipitated phases: According to the composition of cupronickel and the microstructure of the comparative example after the secondary annealing, new precipitated phases may be formed during the third annealing of the embodiment, or the existing precipitated phases may grow and coarsen. The existence and distribution of these precipitated phases will have an important impact on the properties of cupronickel, such as improving ductility and strength.

[0149] Further elimination of residual stress: Although the secondary annealing has eliminated most of the residual stress, there may still be a small amount of residual stress. The third annealing can further reduce the residual stress, making the structure and properties of the white copper more stable and the ductility more outstanding.

[0150] The underlined data above do not meet the requirements of the present invention.

[0151] The description of the above embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

1. A BZN15-20 zinc-nickel copper strip, characterized in that: The BZN15-20 zinc-nickel copper strip includes the following components in percentage by mass: Cu 62.2-64.8%, Fe 0.15-0.20%, Ni 13.5-15.5%, Pb≤0.01%, and Zn as the balance.

2. The BZN15-20 zinc-nickel copper strip according to claim 1, characterized in that: The tensile strength of the BZN15-20 zinc-nickel copper strip is ≥410N / mm 2 , yield strength ≥305N / mm 2 , elongation ≥40%, Vickers hardness ≥95HV.

3. A method for producing the BZN15-20 zinc-nickel copper strip according to claim 1 or 2, characterized in that: The production method comprises the following process flow: 1) Melting; 2) Casting; 3) Milling; 4) Rough rolling; 5) trimming; 6) primary annealing; 7) Thick belt cleaning; 8) Finished products of intermediate rolling; 9) Secondary annealing; 10) Three annealings; 11) Thin strip cleaning; 12) Pulling a little; 13) Divide into strips.

4. The production method according to claim 3, characterized in that: Step 4) Rough rolling, rolling to 1.0 mm, rolling speed 200-300 m / min.

5. The production method according to claim 3, characterized in that: Step 6) primary annealing, annealing temperature is 600-680°C, heating time is 6-8 hours, and heat preservation time is 8-10 hours.

6. The production method according to claim 3, characterized in that: In step 8), the finished product is rolled to a thickness of 0.5 mm, the roughness of the roller is controlled at 0.15 to 0.18 μm, and the rolling speed is controlled at 150 to 180 m / min.

7. The production method according to claim 3, characterized in that: Step 9) secondary annealing, using a controllable continuous atmosphere annealing furnace, the furnace temperature is 700-800°C, the atmosphere N2 content is 98%-99% + H2 content is 1%-1.8%, the annealing speed is 13-17m / min, the tension ratio is unwinding section tension coefficient: inlet looper tension coefficient: furnace zone tension coefficient: braking zone tension coefficient: outlet looper tension coefficient: grinding brush zone tension coefficient: winding section tension coefficient = 12:11:2.4:11:11:13:20, heating zone fan speed: 1100rpm, hot and cold zone fan speed: 1100rpm.

8. The production method according to claim 3 or 7, characterized in that: Step 10) annealing three times, using a bell-shaped furnace, annealing temperature of 440-480°C, heating time: 4-6 hours, and insulation time of 5-8 hours.

9. The production method according to claim 3, characterized in that: Step 12) Straightening, using a straightening machine, speed 150m / min, plate shape <5I.

Images