A method for producing high-gloss c7451 cupronickel strip

Abstract

The application discloses a production method of high-gloss C7451 cupronickel strip, and comprises the following steps: melting and casting, face milling, rough rolling, thick shearing, first-time shield annealing, degreasing and cleaning, pre-finishing rolling, loose coiling, second-time shield annealing, degreasing and cleaning, finishing rolling, air cushion furnace annealing, loose coiling, third-time shield annealing, degreasing and cleaning, bending and straightening, and finished product slitting; in the finishing rolling step, 2 passes of rolling are carried out, the second pass reduction is controlled to be 5-10%, the total reduction of the finishing rolling is controlled to be more than 30%, and the roughness of the finishing rolling roller is controlled to be 0.05-0.15 microns; the method can stably produce the high-gloss C7451 cupronickel strip with a tensile strength of 540-590 MPa, an elongation of 10-15%, a hardness of 160-175 HV, and a glossiness of more than 350 GU.

Description

Technical Field

[0001] This invention belongs to the field of cupronickel production technology, specifically relating to a method for producing high-gloss C7451 cupronickel strip. Background Technology

[0002] With the rapid development of the electronics industry in today's society, copper strips are playing an increasingly important role, and their application scope is constantly expanding, enjoying excellent development in the market. As technology advances, various components are gradually moving towards smaller and more precise designs, and the demand for traceability of component materials is increasing. The emergence of requirements such as marking components with QR codes has led to the development of high-gloss materials.

[0003] When supplying copper strips, customers have specific requirements for the performance and gloss of the copper strips, but traditional production processes cannot simultaneously meet the requirements of stable high performance and high gloss. CN 113737053 A discloses a tin-phosphor bronze plate and strip with controllable gloss and its preparation method, including the following steps: (1) subjecting the tin-phosphor bronze ingot to a homogenization annealing, pre-rolling, a second homogenization annealing and initial rolling in sequence to obtain initial rolled tin-phosphor bronze; (2) subjecting the initial rolled tin-phosphor bronze in step (1) to a bell-type annealing, pre-finish rolling and a second bell-type annealing in sequence to obtain pre-finish rolled tin-phosphor bronze; (3) subjecting the pre-finish rolled tin-phosphor bronze in step (2) to finish rolling and stress-relief annealing in sequence to obtain tin-phosphor bronze plate and strip; this method is for tin-phosphor bronze plate and strip, and the performance and gloss stability of the tin-phosphor bronze plate and strip produced by this method are relatively poor.

[0004] Existing technologies often employ electroplating to achieve a high gloss finish on copper alloy surfaces, but this method causes some environmental damage and does not align with environmental protection principles. Summary of the Invention

[0005] The purpose of this invention is to provide a method for producing high-gloss C7451 cupronickel strip. This method can stably produce high-gloss C7451 cupronickel strip with a tensile strength of 540-590 MPa, an elongation of 10-15%, a hardness of 160-175 HV, and a gloss of ≥350 GU.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for producing high-gloss C7451 white copper strip, comprising the following steps: casting, milling, rough rolling, thick shearing, first Hatchery annealing, degreasing and cleaning, pre-finish rolling, uncoiling, second Hatchery annealing, degreasing and cleaning, finish rolling, air cushion furnace annealing, uncoiling, third Hatchery annealing, degreasing and cleaning, tension straightening, and finished product slitting; in the finish rolling step, two passes are performed, the reduction rate of the second pass is controlled at 5-10%, the total reduction rate of finish rolling is controlled at more than 30%, and the roughness of the finish rolling rolls is controlled at 0.05-0.15μm.

[0008] In the air cushion furnace annealing step, the annealing temperature is 600-700℃ and the speed is 30-40m / min, preferably the annealing temperature is 650℃ and the speed is 33m / min.

[0009] In the rough rolling step, the rough rolling reduction rate is 80-95%. The purpose of using a higher reduction rate is to make full use of the softening and work hardening properties of the material without cracking during rolling, to minimize the rolling stroke and shorten the processing time; at the same time, it makes the internal grain structure more thoroughly broken, which is conducive to subsequent softening annealing.

[0010] In the pre-finishing rolling step, the pre-finishing rolling reduction rate is 60-75%. The purpose of using a higher reduction rate is to make full use of the material's softening and work hardening properties, minimize the rolling stroke, and shorten the processing time, without causing cracks during rolling. At the same time, it makes the internal grain structure more thoroughly broken, which is conducive to subsequent softening annealing.

[0011] In the first annealing step, the annealing conditions are: annealing temperature 600-650℃, annealing time 8-10h; the purpose of using this temperature range is to fully soften the material without causing material adhesion.

[0012] In the second annealing step, the annealing conditions are: annealing temperature 550-600℃, annealing time 8-10h; the purpose of using this temperature range is to fully soften the material without causing material adhesion.

[0013] In the third annealing step, the annealing conditions are: annealing temperature 420-450℃, annealing time 4-8h; the purpose of using this temperature range is to remove the internal stress of the material without affecting its gloss.

[0014] The production method of high-gloss C7451 cupronickel strip provided by this invention involves two rolling passes in the finishing rolling step, with the reduction rate of the second pass controlled at 5-10%, the total reduction rate of finishing rolling exceeding 30%, and the surface roughness of the finishing rolls controlled at 0.05-0.15 μm. This results in a high-gloss surface after finishing rolling. Following finishing rolling, an air-cushion furnace softening annealing process is performed to stabilize the material properties within the standard requirements, yielding a stable high-performance and high-gloss material.

[0015] Compared with existing technologies, the production method provided by this invention is simple, and the performance of the produced cupronickel strip is stable and controllable. It can produce high-gloss C7451 cupronickel strips with performance fully meeting the JIS standard range, with tensile strength of 540-640 MPa, elongation ≥3%, hardness of 150-180 HV, and gloss ≥350 GU. Detailed Implementation

[0016] This invention provides a method for producing high-gloss C7451 white copper strip, the method comprising the following steps: casting—milling—rough rolling—thick shearing—first annealing—degreasing and cleaning—pre-finish rolling—uncoiling—second annealing—degreasing and cleaning—finish rolling—air cushion furnace annealing—uncoiling—third annealing—degreasing and cleaning—tension bending and straightening—finished product slitting;

[0017] In the roughing step, the roughing reduction rate is 80-95%;

[0018] In the pre-finishing rolling step, the pre-finishing rolling reduction rate is 60-75%;

[0019] In the first annealing step, the annealing conditions are 600-650℃ / 10h;

[0020] In the second annealing step, the annealing conditions are 550-600℃ / 8h;

[0021] In the finishing rolling step, two rolling passes are performed, with the reduction rate of the second pass controlled at 5-10%, and the total reduction rate of finishing rolling controlled at over 30%.

[0022] In the air cushion furnace annealing step, the annealing temperature is 600-700℃ and the speed is 30-40m / min, preferably the annealing temperature is 650℃ and the speed is 33m / min;

[0023] In the third annealing step, the annealing conditions are 420-450℃ / 5h.

[0024] The present invention will now be described in detail with reference to the embodiments.

[0025] The chemical composition and weight percentage of the C7451 cupronickel strips in the following embodiments and comparative examples are shown in Table 1.

[0026] Table 1

[0027]

[0028] The production steps of the C7451 cupronickel strip in each embodiment are as follows:

[0029] The production process is as follows: casting, milling, rough rolling, thick shearing, first annealing at the sulphur-Bauer, degreasing and cleaning, pre-finishing rolling, uncoiling, second annealing at the sulphur-Bauer, degreasing and cleaning, two-pass finishing rolling, air cushion furnace annealing, uncoiling, third annealing at the sulphur-Bauer, degreasing and cleaning, tension bending and straightening, and finished product slitting. The production process parameters are shown in Table 2.

[0030] Table 2

[0031]

[0032]

[0033] The production steps of C7451 cupronickel strip in each comparative example are as follows: casting—milling—rough rolling—thick shearing—first annealing—degreasing and cleaning—intermediate rolling—uncoiling—second annealing—degreasing and cleaning—pre-finish rolling—uncoiling—third annealing—degreasing and cleaning—finish rolling in one pass—uncoiling—fourth annealing—degreasing and cleaning—tension bending and straightening—finished product slitting; the production process parameters are shown in Table 3.

[0034] Table 3

[0035] Roughing reduction rate / % 93.1％ 93.1％ First annealing conditions 650℃ / 10h 650℃ / 10h Intermediate rolling reduction rate / % 70％ 67.7％ Second annealing conditions 550℃ / 8h 550℃ / 8h Pre-rolling reduction rate / % 23％ / Third annealing conditions 550℃ / 8h / Finishing reduction rate / % 13％ 38％ Finishing roll roughness / μm 0.10 0.10 Fourth annealing conditions 420℃ / 5h 420℃ / 5h

[0036] The properties of the C7451 cupronickel strips produced in the above embodiments and comparative examples are shown in Table 4.

[0037] Table 4

[0038]

[0039]

[0040] As can be seen from the above, the production method provided by the present invention can stably produce high-gloss C7451 white copper strip with a tensile strength of 540-590 MPa, an elongation of 10-15%, a hardness of 160-175 HV, and a gloss of ≥350 GU.

[0041] The above detailed description of a method for producing a high-gloss C7451 white copper strip with reference to the embodiments is illustrative rather than limiting. Several embodiments can be listed within the defined scope. Therefore, variations and modifications without departing from the overall concept of the present invention should be within the protection scope of the present invention.

Claims

1. A method for producing high-gloss C7451 white copper strip, characterized in that, The production method includes the following steps: casting, milling, rough rolling, thick shearing, first annealing in a stencil, degreasing and cleaning, pre-finishing rolling, uncoiling, second annealing in a stencil, degreasing and cleaning, finishing rolling, air cushion furnace annealing, uncoiling, third annealing in a stencil, degreasing and cleaning, stretching and straightening, and finished product slitting. In the roughing rolling step, the roughing reduction rate is 85-95%; In the pre-finishing rolling step, the pre-finishing reduction rate is 60-75%; The second annealing step is as follows: the annealing conditions are: annealing temperature 550-600℃, annealing time 8-10h; In the finishing rolling step, two rolling passes are performed, with the finishing rolling reduction rate controlled at more than 30%, and the second passing reduction rate controlled at 5-10%. The surface roughness of the finishing rolling rolls is controlled at 0.05-0.15μm. In the air cushion furnace annealing step, the annealing temperature is 600~700℃ and the speed is 30~40m / min; The third annealing step is as follows: annealing conditions are: annealing temperature 420-450℃, annealing time 4-8h; The high-gloss C7451 white copper strip has a tensile strength of 540~640MPa, an elongation of ≥3%, a hardness of 150~180HV, and a gloss of ≥350 GU.

2. The production method according to claim 1, characterized in that, In the air cushion furnace annealing step, the annealing temperature is 650℃ and the speed is 33m / min.

3. The production method according to claim 1, characterized in that, The first annealing step is as follows: annealing conditions are: annealing temperature 600-650℃, annealing time 8-10h.

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