A process for producing a zinc white copper strip

Abstract

The application discloses a preparation process of zinc white copper strip, and the process flow comprises the following steps: face milling, rough rolling, recrystallization annealing, cleaning, medium rolling, grading annealing, cleaning, finish rolling, finished product annealing, cleaning, bending and straightening, cutting and warehousing; wherein, the grading annealing is divided into three stages, the first stage annealing temperature is 655-680 DEG C, the holding time is 1-2h, the second stage annealing temperature is 580-610 DEG C, the holding time is 3-4h, and the third stage annealing temperature is 525-540 DEG C, the holding time is 3-4h. The zinc white copper strip prepared by the application has high strength and elasticity, good corrosion resistance and high-temperature oxidation resistance, and does not change color under 300 DEG C for 3min.

Description

Technical Field

[0001] This invention belongs to the field of copper alloy processing technology, and specifically relates to a preparation process for zinc-copper strip. Background Technology

[0002] Zinc-copper alloy is a ternary alloy composed of zinc added to a copper-nickel alloy. It possesses a silvery-white metallic luster and exhibits excellent machinability, corrosion resistance, and mechanical properties. Suitable for cold-working, it produces a high-smooth surface finish after machining and is widely used in the manufacture of corrosion-resistant structural components, such as springs, sockets, and housings for various precision instruments and advanced electronic components. Zinc-copper alloy containing a small amount of lead has good machinability and cold-working properties and is extensively used in the manufacture of precision parts for watches and optical instruments. Furthermore, zinc-copper alloy also has wide applications in musical instruments, tableware, eyeglass frames, and decorative engineering.

[0003] Currently, the general manufacturing process for zinc-copper strip is as follows: smelting and casting → milling → cold rolling → recrystallization annealing → cleaning → pre-finish rolling → recrystallization annealing → cleaning → finish rolling → finished product annealing → cleaning → tension bending and straightening → slitting and warehousing. The processing rate during cold working should not be too high, resulting in strips with high strength, elasticity, and good corrosion resistance. However, during use, zinc-copper strips often require brazing to connect with other parts, making them susceptible to high-temperature oxidation and discoloration. The discoloration is generally believed to be caused by surface dezincification; therefore, existing technologies mostly use grinding to remove the dezincified layer, followed by cleaning. While this generally meets performance requirements, the yield is low, and the added grinding and cleaning process lengthens the production process and increases costs. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a zinc-copper strip preparation process that can improve the high-temperature oxidation resistance of zinc-copper strip and reduce production costs.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A process for preparing zinc-copper strip includes the following steps: milling, rough rolling, recrystallization annealing, cleaning, intermediate rolling, graded annealing, cleaning, finish rolling, finished product annealing, cleaning, tension bending and straightening, slitting and warehousing.

[0007] The graded annealing process is divided into three stages: the first stage annealing temperature is 655-680℃ and the holding time is 1-2 hours; the second stage annealing temperature is 580-610℃ and the holding time is 3-4 hours; and the third stage annealing temperature is 525-540℃ and the holding time is 3-4 hours.

[0008] Preferably, the zinc-copper alloy is one of BZn15-20, BZn18-18, BZn18-20, or BZn18-26.

[0009] Preferably, the total deformation of the rough rolling is 70-75%.

[0010] Preferably, the recrystallization annealing temperature is 695–720°C and the time is 5–6 hours.

[0011] Preferably, the total deformation of the intermediate rolling mill is 80-85%.

[0012] Preferably, the total deformation of the finishing roll is 80-90%.

[0013] Preferably, the annealing temperature of the finished product is 355-385°C, and the time is 8-10 hours.

[0014] Preferably, the recrystallization annealing, graded annealing, and finished product annealing are carried out in a bell-type annealing furnace, and the gas atmosphere inside the annealing furnace is 75 vt% hydrogen and 25 vt% nitrogen.

[0015] Preferably, the cleaning process is as follows: first, acid washing with a sulfuric acid concentration of 10-13% at room temperature; then, alkaline washing with an alkaline solution concentration of 3-5% at 70-80°C; followed by anti-oxidation treatment with a treatment solution of a mixture of benzotriazole, sodium silicate, and dodecyl mercaptan at a concentration of 0.05-0.08 g / L at 60-80°C; and finally, rinsing with clean water at a cleaning speed of 30-40 m / min.

[0016] Preferably, the surface roughness of the rolls used in the roughing mill is 0.3 to 0.4 μm, the surface roughness of the rolls used in the intermediate mill is 0.2 to 0.3 μm, and the surface roughness of the rolls used in the finishing mill is 0.1 to 0.2 μm.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] The preparation process of this invention changes the recrystallization annealing after intermediate rolling to staged annealing, which prevents incomplete crystallization and avoids dezincification during annealing and subsequent finishing rolling. The zinc-copper strip prepared by this invention has high strength and elasticity, good corrosion resistance and high-temperature oxidation resistance, and can remain unchanged in color after holding at 300°C for 3 minutes. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to specific embodiments, so that those skilled in the art can more clearly understand the present invention. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention. In the embodiments of the present invention, unless otherwise specified, all raw material components are commercially available products well known to those skilled in the art; unless specifically specified, the technical means used are all conventional means well known to those skilled in the art.

[0020] The present invention provides a process for preparing zinc-copper strip, the process flow of which includes the following steps: milling, rough rolling, recrystallization annealing, cleaning, intermediate rolling, graded annealing, cleaning, finish rolling, finished product annealing, cleaning, tension bending and straightening, slitting and warehousing;

[0021] The graded annealing process consists of three stages: the first stage annealing temperature is 655-680℃ and the holding time is 1-2 hours; the second stage annealing temperature is 580-610℃ and the holding time is 3-4 hours; and the third stage annealing temperature is 525-540℃ and the holding time is 3-4 hours.

[0022] In some preferred embodiments, the zinc-copper alloy is one of BZn15-20, BZn18-18, BZn18-20, and BZn18-26.

[0023] In some preferred embodiments, the total deformation of the rough rolling is 70-75%.

[0024] In some preferred embodiments, the recrystallization annealing temperature is 695–720°C and the time is 5–6 hours.

[0025] In some preferred embodiments, the total deformation of the intermediate rolling mill is 80-85%.

[0026] In some preferred embodiments, the total deformation of the finishing roll is 80-90%.

[0027] In some preferred embodiments, the annealing temperature of the finished product is 355–385°C, and the time is 8–10 hours.

[0028] In some preferred embodiments, recrystallization annealing, graded annealing, and finished product annealing are carried out in a bell-type annealing furnace, with a gas atmosphere of 75 vt% hydrogen and 25 vt% nitrogen.

[0029] In some preferred embodiments, the cleaning steps are as follows: first, acid washing with sulfuric acid concentration of 10-13% at room temperature; then, alkaline washing with alkaline solution concentration of 3-5% at 70-80°C; followed by anti-oxidation treatment with a treatment solution of benzotriazole, sodium silicate, and dodecyl mercaptan at a concentration of 0.05-0.08 g / L at 60-80°C; and finally, rinsing with clean water at a cleaning speed of 30-40 m / min.

[0030] In some preferred embodiments, the surface roughness of the rolls used for roughing is 0.3 to 0.4 μm, the surface roughness of the rolls used for intermediate rolling is 0.2 to 0.3 μm, and the surface roughness of the rolls used for finishing rolling is 0.1 to 0.2 μm.

[0031] Example 1

[0032] In this embodiment, zinc-nickel strip is prepared using a zinc-nickel ingot of grade BZn18-26. The preparation method is as follows:

[0033] (1) Milling: Mill the 640×160mm billet on all four sides, with 0.8mm milled on the top and bottom surfaces and 1mm milled on the sides.

[0034] (2) Rough rolling: Cold billet rough rolling is carried out using a four-roll reversible rolling mill with 7 rolling passes and a total deformation of 71%. The surface roughness of the rolls used is 0.3μm.

[0035] (3) Recrystallization annealing: Recrystallization annealing was carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature was 700℃ and the holding time was 6h.

[0036] (4) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.08 g / L at 60℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0037] (5) Intermediate rolling: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 82.6%. The surface roughness of the rolls used is 0.2μm.

[0038] (6) Graded annealing: Graded annealing is carried out in a bell-type annealing furnace under the protection of 75vt% hydrogen and 25vt% nitrogen atmosphere. The graded annealing is divided into three stages: the first stage annealing temperature is 660℃ and the holding time is 2h; the second stage annealing temperature is 580℃ and the holding time is 4h; and the third stage annealing temperature is 530℃ and the holding time is 4h.

[0039] (7) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.08 g / L and a temperature of 60℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0040] (8) Finishing: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 87.5%. The surface roughness of the rolls used is 0.1μm.

[0041] (9) Finished product annealing: Finished product annealing is carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature is 360℃ and the holding time is 10h.

[0042] (10) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.08 g / L and a temperature of 60℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0043] (11) Bending and straightening, cutting and storing.

[0044] Example 2

[0045] In this embodiment, zinc-nickel strip is prepared using a zinc-nickel ingot of grade BZn18-18. The preparation method is as follows:

[0046] (1) Milling: Mill the 640×160mm billet on all four sides, with 0.8mm milled on the top and bottom surfaces and 1mm milled on the sides.

[0047] (2) Rough rolling: Cold billet rough rolling is carried out using a four-roll reversible rolling mill with 7 rolling passes and a total deformation of 74.7%. The surface roughness of the rolls used is 0.3μm.

[0048] (3) Recrystallization annealing: Recrystallization annealing was carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature was 720℃ and the holding time was 5h.

[0049] (4) Cleaning: First, acid wash with sulfuric acid concentration of 10% at room temperature; then, alkali wash with alkali concentration of 3% at 80℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.05g / L at 80℃; finally, rinse with clean water and dry; the cleaning speed is 35m / min.

[0050] (5) Intermediate rolling: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 85%. The surface roughness of the rolls used is 0.2μm.

[0051] (6) Graded annealing: Graded annealing is carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75% hydrogen and 25% nitrogen. The graded annealing is divided into three stages: the first stage annealing temperature is 680℃ and the holding time is 1h; the second stage annealing temperature is 610℃ and the holding time is 3h; and the third stage annealing temperature is 540℃ and the holding time is 3h.

[0052] (7) Cleaning: First, acid wash with sulfuric acid concentration of 10% at room temperature; then, alkali wash with alkali concentration of 3% at 80℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.05g / L at 80℃; finally, rinse with clean water and dry; the cleaning speed is 35m / min.

[0053] (8) Finishing: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 86.7%. The surface roughness of the rolls used is 0.1μm.

[0054] (9) Finished product annealing: Finished product annealing is carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature is 380℃ and the holding time is 8h.

[0055] (10) Cleaning: First, acid wash with sulfuric acid concentration of 10% at room temperature; then, alkali wash with alkali concentration of 3% at 80℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.05g / L at 80℃; finally, rinse with clean water and dry; the cleaning speed is 35m / min.

[0056] (11) Bending and straightening, cutting and storing.

[0057] Example 3

[0058] In this embodiment, zinc-nickel strip is prepared using a zinc-nickel ingot of grade BZn18-20. The preparation method is as follows:

[0059] (1) Milling: Mill the 640×160mm billet on all four sides, with 0.8mm milled on the top and bottom surfaces and 1mm milled on the sides.

[0060] (2) Rough rolling: Cold billet rough rolling is carried out using a four-roll reversible rolling mill with 7 rolling passes and a total deformation of 72.2%. The surface roughness of the rolls used is 0.3μm.

[0061] (3) Recrystallization annealing: Recrystallization annealing was carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature was 710℃ and the holding time was 6h.

[0062] (4) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.06 g / L at 70℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0063] (5) Intermediate rolling: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 84.1%. The surface roughness of the rolls used is 0.2μm.

[0064] (6) Graded annealing: Graded annealing is carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75% hydrogen and 25% nitrogen. The graded annealing is divided into three stages: the first stage annealing temperature is 670℃ and the holding time is 2h; the second stage annealing temperature is 600℃ and the holding time is 3h; and the third stage annealing temperature is 530℃ and the holding time is 4h.

[0065] (7) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.06 g / L at 70℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0066] (8) Finishing: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 82.9%. The surface roughness of the rolls used is 0.1μm.

[0067] (9) Finished product annealing: Finished product annealing is carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature is 370℃ and the holding time is 9h.

[0068] (10) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.06 g / L at 70℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0069] (11) Bending and straightening, cutting and storing.

[0070] Example 4

[0071] In this embodiment, zinc-nickel strip is prepared using a zinc-nickel ingot of grade BZn15-20. The preparation method is as follows:

[0072] (1) Milling: Mill the 640×160mm billet on all four sides, with 0.8mm milled on the top and bottom surfaces and 1mm milled on the sides.

[0073] (2) Rough rolling: Cold billet rough rolling is carried out using a four-roll reversible rolling mill with 7 rolling passes and a total deformation of 73.5%. The surface roughness of the rolls used is 0.3μm.

[0074] (3) Recrystallization annealing: Recrystallization annealing was carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature was 700℃ and the holding time was 6h.

[0075] (4) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.06 g / L at 70℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0076] (5) Intermediate rolling: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 83.3%. The surface roughness of the rolls used is 0.2μm.

[0077] (6) Graded annealing: Graded annealing is carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75% hydrogen and 25% nitrogen. The graded annealing is divided into three stages: the first stage annealing temperature is 670℃ and the holding time is 2h; the second stage annealing temperature is 590℃ and the holding time is 3h; and the third stage annealing temperature is 530℃ and the holding time is 4h.

[0078] (7) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.06 g / L at 70℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0079] (8) Finishing: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 85.7%. The surface roughness of the rolls used is 0.1μm.

[0080] (9) Finished product annealing: Finished product annealing is carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature is 365℃ and the holding time is 9h.

[0081] (10) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.06 g / L at 70℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0082] (11) Bending and straightening, cutting and storing.

[0083] Comparative Example 1

[0084] This comparative example uses zinc-copper alloy cast billets of grade BZn18-26 to prepare zinc-copper alloy strips. The preparation method is as follows:

[0085] (1) Milling: Mill the 640×160mm billet on all four sides, with 0.8mm milled on the top and bottom surfaces and 1mm milled on the sides.

[0086] (2) Rough rolling: Cold billet rough rolling is carried out using a four-roll reversible rolling mill with 7 rolling passes and a total deformation of 71%. The surface roughness of the rolls used is 0.3μm.

[0087] (3) Recrystallization annealing: Recrystallization annealing was carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature was 700℃ and the holding time was 6h.

[0088] (4) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.08 g / L at 60℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0089] (5) Intermediate rolling: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 82.6%. The surface roughness of the rolls used is 0.2μm.

[0090] (6) Recrystallization annealing: Recrystallization annealing was carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature was 660℃ and the holding time was 10h.

[0091] (7) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.08 g / L and a temperature of 60℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0092] (8) Finishing: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 87.5%. The surface roughness of the rolls used is 0.1μm.

[0093] (9) Finished product annealing: Finished product annealing is carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature is 360℃ and the holding time is 10h.

[0094] (10) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.08 g / L and a temperature of 60℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0095] (11) Bending and straightening, cutting and storing.

[0096] Comparative Example 2

[0097] This comparative example uses zinc-copper alloy cast billets of grade BZn18-26 to prepare zinc-copper alloy strips. The preparation method is as follows:

[0098] (1) Milling: Mill the 640×160mm billet on all four sides, with 0.8mm milled on the top and bottom surfaces and 1mm milled on the sides.

[0099] (2) Rough rolling: Cold billet rough rolling is carried out using a four-roll reversible rolling mill with 7 rolling passes and a total deformation of 71%. The surface roughness of the rolls used is 0.3μm.

[0100] (3) Recrystallization annealing: Recrystallization annealing was carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature was 700℃ and the holding time was 6h.

[0101] (4) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.08 g / L at 60℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0102] (5) Intermediate rolling: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 82.6%. The surface roughness of the rolls used is 0.2μm.

[0103] (6) Recrystallization annealing: Recrystallization annealing was carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature was 530℃ and the holding time was 11h.

[0104] (7) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.08 g / L and a temperature of 60℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0105] (8) Finishing: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 87.5%. The surface roughness of the rolls used is 0.1μm.

[0106] (9) Finished product annealing: Finished product annealing is carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature is 360℃ and the holding time is 10h.

[0107] (10) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.08 g / L and a temperature of 60℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0108] (11) Bending and straightening, cutting and storing.

[0109] Comparative Example 3

[0110] This comparative example uses zinc-copper alloy cast billets of grade BZn18-26 to prepare zinc-copper alloy strips. The preparation method is as follows:

[0111] (1) Milling: Mill the 640×160mm billet on all four sides, with 0.8mm milled on the top and bottom surfaces and 1mm milled on the sides.

[0112] (2) Rough rolling: Cold billet rough rolling is carried out using a four-roll reversible rolling mill with 7 rolling passes and a total deformation of 71%. The surface roughness of the rolls used is 0.3μm.

[0113] (3) Recrystallization annealing: Recrystallization annealing was carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature was 700℃ and the holding time was 6h.

[0114] (4) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.08 g / L at 60℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0115] (5) Intermediate rolling: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 82.6%. The surface roughness of the rolls used is 0.2μm.

[0116] (6) Graded annealing: Graded annealing is carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The graded annealing is divided into two stages: the first stage annealing temperature is 660℃ and the holding time is 5h; the second stage annealing temperature is 530℃ and the holding time is 5h.

[0117] (7) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.08 g / L and a temperature of 60℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0118] (8) Finishing: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 87.5%. The surface roughness of the rolls used is 0.1μm.

[0119] (9) Finished product annealing: Finished product annealing is carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature is 360℃ and the holding time is 10h.

[0120] (10) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.08 g / L and a temperature of 60℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0121] (11) Bending and straightening, cutting and storing.

[0122] Comparative Example 4

[0123] This comparative example uses zinc-copper alloy cast billets of grade BZn18-26 to prepare zinc-copper alloy strips. The preparation method is a conventional method, as follows:

[0124] (1) Milling: Mill the 640×160mm billet on all four sides, with 0.8mm milled on the top and bottom surfaces and 1mm milled on the sides.

[0125] (2) Rough rolling: Cold billet rough rolling is carried out using a four-roll reversible rolling mill with 7 rolling passes and a total deformation of 71%. The surface roughness of the rolls used is 0.3μm.

[0126] (3) Recrystallization annealing: Recrystallization annealing was carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature was 700℃ and the holding time was 6h.

[0127] (4) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.08 g / L at 60℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0128] (5) Intermediate rolling: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 82.6%. The surface roughness of the rolls used is 0.2μm.

[0129] (6) Recrystallization annealing: Recrystallization annealing was carried out in a bell-type annealing furnace under the protection of an atmosphere containing 75vt% hydrogen and 25vt% nitrogen. The annealing temperature was 700℃ and the holding time was 8h.

[0130] (7) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.08 g / L and a temperature of 60℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0131] (8) Finishing: Cold rolling is carried out using a four-roll reversible rolling mill with 8 rolling passes and a total deformation of 87.5%. The surface roughness of the rolls used is 0.1μm.

[0132] (9) Finished product annealing: Finished product annealing is carried out in a bell-type annealing furnace under the protection of 75vt% hydrogen and 25vt% nitrogen atmosphere, with an annealing temperature of 560℃ and a holding time of 8h.

[0133] (10) Cleaning: First, acid wash with sulfuric acid concentration of 13% at room temperature; then, alkali wash with alkali concentration of 5% at 70℃; then, anti-oxidation treatment is carried out with a mixture of benzotriazole, sodium silicate and dodecyl mercaptan at a concentration of 0.08 g / L and a temperature of 60℃; finally, rinse with clean water and dry; the cleaning speed is 35 m / min.

[0134] (11) Bending and straightening, cutting and storing.

[0135] The zinc-copper strips prepared in the above embodiments and comparative examples were subjected to performance tests. Table 1 shows the mechanical property test results, and Table 2 shows the high-temperature oxidation resistance test results.

[0136] Table 1

[0137] Example 1 684 234 131 12 Example 2 612 203 128 13 Example 3 608 196 125 15 Example 4 596 180 128 12 Comparative Example 1 642 208 118 13 Comparative Example 2 593 197 110 15 Comparative Example 3 612 202 118 13 Comparative Example 4 681 235 125 12

[0138] It can be seen that the strip prepared in the embodiments of the present invention has high strength and elasticity, and its elastic modulus is significantly improved compared with existing conventional technologies.

[0139] After keeping the sample at 260-300℃ for 3 minutes in an electric thermostatic drying oven, the surface color change was observed. The results are shown in Table 2.

[0140] Table 2

[0141] Example 1 No color change No color change No color change Example 2 No color change No color change No color change Example 3 No color change No color change No color change Example 4 No color change No color change No color change Comparative Example 1 Yellowing Yellowing Yellowing Comparative Example 2 Yellowing Yellowing Yellowing Comparative Example 3 Slightly yellow Yellowing Yellowing Comparative Example 4 Slightly yellow Yellowing Yellowing

[0142] It can be seen that the zinc-copper strip prepared by the present invention can remain unchanged after being kept at 300℃ for 3 minutes, and its high-temperature oxidation resistance is better than that of zinc-copper strip prepared by traditional process. Its tensile strength, hardness, elongation and other properties are comparable to the mechanical properties of zinc-copper strip prepared by traditional process, but its elastic modulus is significantly improved.

[0143] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A process for preparing zinc-copper alloy strip, characterized in that, The process flow includes the following steps: milling, rough rolling, recrystallization annealing, cleaning, intermediate rolling, graded annealing, cleaning, finish rolling, finished product annealing, cleaning, tension bending and straightening, slitting and warehousing; The graded annealing is divided into three stages: the first stage annealing temperature is 655~680℃ and the holding temperature is 1~2h; the second stage annealing temperature is 580~610℃ and the holding temperature is 3~4h; and the third stage annealing temperature is 525~540℃ and the holding temperature is 3~4h. The zinc-copper alloy is one of the following grades: BZn15-20, BZn18-18, BZn18-20, and BZn18-26. The recrystallization annealing temperature is 695~720℃, and the time is 5~6h; The annealing temperature of the finished product is 355~385℃, and the time is 8~10h; The cleaning process is as follows: first, acid washing with sulfuric acid at a concentration of 10-13% at room temperature; then, alkaline washing with an alkaline solution at a concentration of 3-5% at a temperature of 70-80℃; followed by anti-oxidation treatment with a mixture of benzotriazole, sodium silicate, and dodecyl mercaptan at a concentration of 0.05-0.08 g / L at a temperature of 60-80℃; and finally, rinsing with clean water. The cleaning speed is 30-40 m / min.

2. The preparation process of zinc-copper alloy strip according to claim 1, characterized in that, The total deformation of the roughing roll is 70-75%.

3. The preparation process of zinc-copper alloy strip according to claim 1, characterized in that, The total deformation of the intermediate rolling mill is 80-85%.

4. The preparation process of zinc-copper strip according to claim 1, characterized in that, The total deformation of the finishing mill is 80-90%.

5. The preparation process of zinc-copper strip according to claim 1, characterized in that, The recrystallization annealing, graded annealing, and finished product annealing are carried out in a bell-type annealing furnace, with a gas atmosphere of 75 vt% hydrogen and 25 vt% nitrogen.

6. The preparation process of zinc-copper alloy strip according to claim 1, characterized in that, The surface roughness of the rolls used in the roughing mill is 0.3~0.4μm, the surface roughness of the rolls used in the intermediate mill is 0.2~0.3μm, and the surface roughness of the rolls used in the finishing mill is 0.1~0.2μm.