Production process for stably preparing quarter hard red copper thin strip

Abstract

The invention discloses a production process for stably preparing a quarter hard red copper thin strip. The production process comprises the steps of casting, hot rolling, double-sided milling, rough rolling, thick strip longitudinal shearing, intermediate rolling, annealing, finish rolling, annealing, straightening and the like. The thickness of the obtained quarter hard red copper thin strip ranges from 0.1 mm to 0.3 mm, the electric conductivity is larger than or equal to 98% IACS, and the Vickers hardness ranges from 60 HV to 75 HV; the problems that a rolling mill does not work or strip thickness tolerance and plate shapes cannot be controlled due to the fact that the rolling machining rate is small or the strip thickness tolerance and the plate shapes cannot be controlled are well solved by adopting a high-elongation drawing mode on an annealing and straightening machine; meanwhile, a rolling procedure and a cleaning procedure are omitted, a straightening procedure is added, the machining time is effectively shortened, the production efficiency is improved, meanwhile, the production energy consumption is reduced, the produced copper strip plate is smoother, subsequent machining is easy, and the production cost is reduced. The material is widely applied to the fields of electronics and electricity, buildings and building materials, heat exchangers and refrigeration, hardware and spring products and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of copper strip processing, and particularly relates to a production process for stably preparing a quarter-hard-state red copper thin strip. BACKGROUND

[0002] Copper and copper alloy strips are indispensable basic metal materials in national economic construction, have excellent electric conductivity, heat conductivity, corrosion resistance, electric connection and electric contact, and are widely used in various industrial fields such as machinery, electronics, automobiles, electric power, communication and transportation. At present, the low-end products of the copper and copper alloy strips produced in China have appeared in excess, but the high-end products still rely on imports. The copper strip processing level in China is generally lagging behind that in developed countries and cannot meet the requirements of the rapidly developing industries.

[0003] The quarter-hard-state refers to that the material is work-hardened after cold working deformation, and then the hardness is reduced through annealing treatment. The hardness is reduced to a certain hardness range between the soft state and the semi-hard state, which is the quarter-hard state. The quarter-hard-state red copper thin strip is widely used in the fields of electronics and electrical appliances, building and building materials, heat exchangers and refrigeration, and hardware and spring products, because the strength of the quarter-hard-state red copper thin strip is moderately improved compared with the soft state, and the strip has good ductility and formability, the electric conductivity is slightly decreased but still excellent, and the strip also has good stress relaxation resistance. However, the grains of the quarter-hard-state red copper thin strip are elongated and broken during the processing, such as rolling and drawing, and a large number of dislocations and other crystal defects are generated in the internal. These defects increase the strength of the material, but also make the material in a high-energy state, so this state is also a kind of "metastable state".

[0004] At present, the existing production process of the quarter-hard-state red copper strip is as follows: melting and casting, face milling, rough rolling, thick strip longitudinal cutting, intermediate annealing, first cleaning, medium rolling 1, annealing (continuous annealing), medium rolling 2, annealing (continuous annealing), finish rolling, second cleaning, slitting, inspection and packaging into the warehouse. The production process of the quarter-hard-state red copper strip has the defects of extremely high control requirement for the rolling precision of the finished product, long process flow, difficult surface control and the like, and it is difficult to meet the requirements of the matching industries in China. In addition, the quarter-hard-state red copper strip is in a rolling processing state, the processing rate is very small, especially for the thin strip below 0.4 mm, the rolling force is very small (≤30 tons), and the general rolling mill cannot normally roll under the condition of the limit rolling force. The plate shape and tolerance are not controlled, and the quarter-hard-state red copper thin strip (≤0.3 mm) cannot be stably obtained. Therefore, it is a technical problem to be solved by the present application to develop a suitable rolling process and annealing process parameters to stably prepare the quarter-hard-state red copper thin strip. SUMMARY

[0005] The purpose of the present application is to solve the problems of the existing production process of the quarter-hard red copper strip, such as high control requirement for the rolling precision of the finished product, long process, difficult surface control, and small processing rate, and the like, which cannot meet the requirements of the matching industry in China, and the strip cannot be normally rolled under the limit rolling force, and the strip shape and tolerance are not controlled.

[0006] To achieve the above-mentioned purpose, the present application is implemented by the following technical solutions:

[0007] The present application provides a production process for stably preparing a quarter-hard red copper strip, comprising the following steps:

[0008] (1) Melting and casting: the molten copper water ingot is drawn into a copper strip blank by using a semi-continuous casting method;

[0009] (2) Hot rolling: the copper strip blank produced in the step (1) is put into a step furnace for heating and hot rolling to form a hot rolling coil;

[0010] (3) Double-side milling: the hot rolling coil produced in the step (2) is milled on the upper and lower surfaces;

[0011] (4) Rough rolling: the hot rolling coil in the step (3) is rough-rolled by using a four-roll reversible rolling / two-stand continuous rolling unit, and the rolling schedule is 8 passes, and the processing rate of each pass is 32% to 40%;

[0012] (5) Thick strip slitting: the thick copper strip after rough rolling is subjected to edge cutting treatment;

[0013] (6) Medium rolling: the copper strip after edge cutting treatment is subjected to medium rolling by using a four-roll reversible rolling / two-stand continuous rolling unit, and the rolling schedule is 3 passes, and the processing rate of each pass is 25% to 35%;

[0014] (7) Annealing: the copper strip after medium rolling is put into an air cushion furnace for continuous annealing at a specific temperature and speed;

[0015] (8) Finish rolling: the copper strip after annealing is rolled to a target specification;

[0016] (9) Annealing: the copper strip after finish rolling is put into an air cushion furnace for continuous annealing at a specific temperature and speed;

[0017] (10) Straightening: the copper strip after annealing is straightened, and a red copper strip with a qualified thickness tolerance is obtained.

[0018] Further, the thickness of the quarter-hard red copper strip is 0.1 mm to 0.3 mm.

[0019] Further, the conductivity of the quarter-hard red copper thin strip is greater than or equal to 98% IACS, and the Vickers hardness is 60-75 HV.

[0020] Further, the temperature of the step-by-step furnace in step (2) is greater than 800 DEG C.

[0021] Further, the annealing temperature in step (7) is 600 DEG C, and the speed is 35-40 m / min.

[0022] Further, the annealing temperature in step (9) is 600 DEG C, and the speed is 60 m / min.

[0023] Further, the straightening elongation in step (10) is 1.2-2.0%, and the straightening strength is 360 MPa.

[0024] Compared with the conventional production process of the quarter-hard red copper thin strip, the present application has the following advantages:

[0025] (1) The present application reduces one rolling and one cleaning process, and increases one straightening process, effectively reduces the processing time, improves the production efficiency, and reduces the production energy consumption.

[0026] (2) The copper strip produced by this process is more flat, and is easy to process subsequently.

[0027] (3) The last process of the present application is annealing + straightening instead of the original rolling + cleaning, and the ductility of the obtained strip is higher, the strip shape can be better controlled, the thickness tolerance is stable, and batch production can be stably carried out.

[0028] (4) The present application adopts the high-elongation drawing method of annealing and straightening machine, which better avoids the problems of small rolling processing rate, non-working rolling mill, and uncontrollable strip thickness tolerance and shape. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is the thickness experiment diagram of the bending and straightening of the embodiment 1 of the present application. DETAILED DESCRIPTION

[0030] The present application will be further described in detail below in combination with the embodiments, so as to more clearly understand the present application, but they do not constitute a limitation on the present application.

[0031] Embodiment 1

[0032] The production process of the present application for stably preparing a quarter-hard red copper thin strip, taking the production of a quarter-hard red copper strip product with a brand of T11050 and a thickness of 0.2 mm (±0.003) as an example, comprises the following steps:

[0033] (1) Melting: the molten copper water is drawn at a speed of 80 mm / min by using a semi-continuous casting method to form a copper strip blank with a specification of 220 mm*630 mm*7000 mm;

[0034] (2) Hot rolling: the copper strip blank produced in the above step (1) is put into a walking beam furnace and heated at a high temperature of more than 800°C for 4 h, and after being discharged, it is processed into a hot-rolled coil with a specification of 18 mm*650 mm by using 8 passes on a hot rolling mill;

[0035] (3) Double-side milling: the copper strip blank subjected to the hot rolling in the above step (2) is milled on the upper and lower surfaces, and the single-side milling amount is about 0.6 mm, and the surface oxide scale and the pressed-in type defects are milled clean;

[0036] (4) Rough rolling: the copper strip blank subjected to the step (3) is subjected to rough rolling by using a four-high reversible rolling / two-stand continuous rolling mill set, the rolling schedule is 8 passes, and the processing rate of each pass is 32% to 40%, and the processing is performed to a cold-rolled coil with a specification of 1.2 mm*650 mm;

[0037] (5) Thick strip slitting: the thick material copper strip after the rough rolling is subjected to edge cutting treatment, and the edge cutting amount is 25 to 30 mm;

[0038] (6) Medium rolling: the copper strip after the edge cutting treatment is subjected to medium rolling by using a four-high reversible rolling / two-stand continuous rolling mill set, the rolling schedule is 3 passes, and the processing rate of each pass is 25% to 35%, and the specification after rolling is 0.55 mm*620 mm;

[0039] (7) Annealing: the copper strip after the medium rolling is put into a gas cushion furnace with a temperature of 600°C, and is subjected to continuous annealing at a speed of 35 to 40 m / min;

[0040] (8) Finish rolling: the copper strip after the annealing is rolled for 3 passes, and the processing rate of each pass is 28 to 32% to roll to a target specification of 0.201±0.003 mm;

[0041] (9) Annealing: the copper strip after the finish rolling is put into a gas cushion furnace with a temperature of 600°C, and is subjected to continuous annealing at a speed of 60 m / min to become soft, and after cleaning, the Vickers hardness HV is 45 to 55;

[0042] (10) Straightening: the copper strip after the annealing is straightened according to the process setting in the following Table 1:

[0043] Table 1

[0044]

[0045] The Vickers hardness value of the quarter-hard copper strip obtained after straightening in this embodiment is 65.4 HV, and the target thickness is 0.2 ± 0.003 mm.

[0046] The 0.201mm thick soft copper strip prepared in this embodiment was subjected to continuous bending tests to obtain the relationship between bending straightening elongation, thickness, and hardness. The experimental data are shown in Table 2 below.

[0047] Table 2 Thickness Experiment for Bending Straightening

[0048] Stretching and bending straightening elongation rate (%) 0 0.5 1.0 1.5 2.0 2.5 Thickness change ratio (%) 100 98.6 98.2 96.8 95.9 93.5 Hardness change (HV) 48.62 58.42 60.95 63.78 64.21 69.73

[0049] Plot the experimental data of the tension-bending straightening thickness in Table 2 above to obtain the attached figure. Figure 1 As can be seen from the figure, at the same thickness, the hardness of the strip increases with the increase of elongation (direct proportional relationship); at the maximum elongation (2.5%), the maximum hardness (HV) can reach about 70; at the same original thickness, the thickness of the strip decreases with the increase of elongation (inverse proportional relationship); at the maximum elongation (2.5%), the thickness of the strip can be reduced to about 93% of the original thickness.

[0050] Example 2

[0051] This embodiment describes a stable production process for preparing quarter-hard copper strips. Taking the production of a 0.15mm (±0.003mm) thick T11050 quarter-hard copper strip as an example, the process includes the following steps:

[0052] (1) Melting and casting: The molten copper is drawn into a copper strip with a specification of 220mm*630mm*7000mm by a semi-continuous casting method at a speed of 80mm / min.

[0053] (2) Hot rolling: The copper strip billet produced in step (1) above is placed in a walking furnace and heated at a high temperature of more than 800°C for 4 hours. After exiting the furnace, it is processed into a hot rolled coil of 18mm*650mm in 8 passes on a hot rolling mill.

[0054] (3) Double-sided milling: The copper strip billet that has been hot rolled in step (2) above is milled on both sides. The milling amount on one side is about 0.6 mm, and the oxide scale and indentation defects on the surface are cleaned.

[0055] (4) Rough rolling: The copper strip billet processed in step (3) is rough rolled using a four-roll reversible rolling / two-stand continuous rolling mill. The rolling process is 8 passes, and the processing rate of each pass is 32% to 40%, and the product is processed into a cold-rolled coil with a specification of 1.2mm*650mm.

[0056] (5) thick strip slitting: the thick copper strip after roughing is subjected to edge cutting treatment, and the edge cutting amount is 25-30 mm;

[0057] (6) medium rolling: the copper strip after edge cutting treatment is subjected to medium rolling through a four-roll reversible rolling / two-stand continuous rolling unit, the rolling schedule is 3 passes, and the reduction of each pass is 25%-35%; the rolled specification is 0.55 mm*620 mm;

[0058] (7) annealing: the copper strip after medium rolling is placed into a gas cushion furnace with a temperature of 600 DEG C, and is subjected to continuous annealing at a speed of 35-40 m / min;

[0059] (8) finish rolling: the copper strip after annealing is rolled for 3 passes, and the reduction of each pass is 28-32% to the target specification of 0.151+ / -0.003 mm;

[0060] (9) annealing: the copper strip after finish rolling is placed into a gas cushion furnace with a temperature of 600 DEG C, and is subjected to continuous annealing at a speed of 60 m / min to become soft, and the Vickers hardness HV after cleaning is 45-55;

[0061] (10) straightening: the copper strip after annealing is straightened according to the process setting in Table 1 to obtain the product.

[0062] The Vickers hardness value of the quarter-hard purple copper thin strip obtained after straightening in this embodiment is 62.1 HV, and the target thickness is 0.15+ / -0.003 mm.

[0063] Example 3

[0064] A production process for stably preparing a quarter-hard purple copper thin strip is provided in this embodiment, which takes the production of a quarter-hard purple copper thin strip product with a brand T11050 and a thickness of 0.25 mm(+ / -0.003) as an example, and includes the following steps:

[0065] (1) melting and casting: the molten copper water is drawn into a billet at a speed of 80 mm / min by using a semi-continuous casting method to form a copper strip billet with a specification of 220 mm*630 mm*7000 mm;

[0066] (2) hot rolling: the copper strip billet produced in the above step (1) is placed into a walking beam furnace and heated at a high temperature of more than 800 DEG C for 4 h, and after being discharged from the furnace, the copper strip billet is processed into a hot-rolled coil with a specification of 18 mm*650 mm by using 8 passes on a hot rolling mill;

[0067] (3) double-side milling: the copper strip billet after hot rolling in the above step (2) is milled on the upper and lower surfaces, and the single-side milling amount is about 0.6 mm, so that the surface oxidation scale and the pressed-in defects are milled clean;

[0068] (4) Rough rolling: the copper strip blank treated in step (3) is rough-rolled by a four-high reversing rolling / two-stand continuous rolling mill set, the rolling schedule is 8 passes, the reduction ratio of each pass is 32%~40%, and the cold-rolled coil with a specification of 1.2mm*650mm is obtained;

[0069] (5) Thick strip slitting: the thick copper strip after rough rolling is subjected to edge cutting treatment, and the edge cutting amount is 25~30mm;

[0070] (6) Medium rolling: the copper strip after edge cutting treatment is subjected to medium rolling by a four-high reversing rolling / two-stand continuous rolling mill set, the rolling schedule is 3 passes, the reduction ratio of each pass is 25%~35%, and the rolled specification is 0.55mm*620mm;

[0071] (7) Annealing: the copper strip after medium rolling is placed in a gas cushion furnace with a temperature of 600℃, and is subjected to continuous annealing at a speed of 35~40m / min;

[0072] (8) Finish rolling: the copper strip after annealing is rolled for 3 passes, the reduction ratio of each pass is 28~32%, and the target specification of 0.252±0.003mm is obtained;

[0073] (9) Annealing: the copper strip after finish rolling is placed in a gas cushion furnace with a temperature of 600℃, and is subjected to continuous annealing at a speed of 60m / min to become soft, and the Vickers hardness HV after cleaning is 45~55;

[0074] (10) Straightening: the copper strip after annealing is straightened according to the process setting in Table 1 to obtain the product.

[0075] The Vickers hardness value of the quarter-hard purple copper thin strip obtained after straightening in this embodiment is 65.3HV, and the target thickness is 0.25±0.003mm.

[0076] Example 4

[0077] A production process for stably preparing a quarter-hard purple copper thin strip is provided in this embodiment, which takes the production of a quarter-hard purple copper thin strip product with a specification of T11050 and a thickness of 0.30mm(±0.003) as an example, and includes the following steps:

[0078] (1) Melting and casting: the molten copper water is drawn into a blank at a speed of 80mm / min by using a semi-continuous casting method to form a copper strip blank with a specification of 220mm*630mm*7000mm;

[0079] (2) Hot rolling: the copper strip blank produced in step (1) above is placed into a walking beam furnace and heated at a high temperature of more than 800℃ for 4h, and then is processed into a hot-rolled coil with a specification of 18mm*650mm by using 8 passes on a hot rolling mill;

[0080] (3) Double side milling: milling the copper strip blank after hot rolling in step (2) from top to bottom, the single side milling amount is about 0.6mm, the surface oxide scale and the pressed-in defects are milled clean;

[0081] (4) Rough rolling: rough rolling the copper strip blank after step (3) by using four-roll reversible rolling / two-stand continuous rolling mill set, the rolling schedule is 8 passes, the processing rate of each pass is 32%~38%, and the processing is to the cold rolling coil with the specification of 1.6*650mm;

[0082] (5) Thick strip longitudinal cutting: cutting the thick copper strip after rough rolling, the cutting amount is 25~30mm;

[0083] (6) Medium rolling: medium rolling the copper strip after cutting by using four-roll reversible rolling / two-stand continuous rolling mill set, the rolling schedule is 3 passes, the processing rate of each pass is 25%~35%, and the specification after rolling is 0.7*620mm;

[0084] (7) Annealing: putting the copper strip after medium rolling into the air cushion furnace with the temperature of 600℃, and continuously annealing at the speed of 35~40m / min;

[0085] (8) Finish rolling: rolling the copper strip after annealing for 3 passes, the processing rate of each pass is 28~32%, and rolling to the target specification of 0.302±0.003mm;

[0086] (9) Annealing: putting the copper strip after finish rolling into the air cushion furnace with the temperature of 600℃, and continuously annealing at the speed of 60m / min to become soft, and cleaning to make the Vickers hardness HV be 45~55;

[0087] (10) Straightening: straightening the copper strip after annealing according to the process setting in Table 1, and obtaining the product.

[0088] The Vickers hardness value of the quarter-hard purple copper thin strip after straightening in this embodiment is 70.1HV, and the target thickness is 0.3±0.003mm.

Claims

1. A stable production process for preparing quarter-hard copper strips, characterized in that, Includes the following steps: (1) Melting and casting: The molten copper is drawn into a billet to form a copper strip billet by a semi-continuous casting method; (2) Hot rolling: The copper strip billet produced in step (1) above is placed into a walking beam furnace and heated and hot rolled into a hot rolled coil; (3) Double-sided milling: The hot-rolled coil produced in step (2) above is milled on both the top and bottom sides; (4) Rough rolling: The hot-rolled coil in step (3) is rough rolled using a four-roll reversible rolling mill / two-stand continuous rolling mill. The rolling process consists of 8 passes, with a processing rate of 32% to 40% for each pass. (5) Thick strip longitudinal shearing: The thick copper strip after rough rolling is trimmed. (6) Intermediate rolling: The copper strip after edge trimming is rolled in an intermediate rolling mill using a four-roll reversible rolling mill / two-stand continuous rolling mill. The rolling process consists of three passes, with a processing rate of 25% to 35% for each pass. (7) Annealing: The copper strip after intermediate rolling is placed in an air cushion furnace and continuously annealed at a specific temperature and rate; (8) Finish rolling: Rolling the annealed copper strip to the target specifications; (9) Annealing: The finely rolled copper strip is placed in an air cushion furnace for continuous annealing at a specific temperature and speed; (10) Straightening: Straighten the annealed copper strip to obtain a copper strip with acceptable thickness tolerance.

2. The production process for stably preparing quarter-hard copper strip according to claim 1, characterized in that: The thickness of the quarter-hard copper strip is 0.1 mm to 0.3 mm.

3. The production process for stably preparing quarter-hard copper strip according to claim 1, characterized in that: The quarter-hard copper strip has a conductivity ≥98% IACS and a Vickers hardness of 60–75 HV.

4. The production process for stably preparing quarter-hard copper strip according to claim 1, characterized in that: In step (2), the temperature of the walking beam furnace is greater than 800 ℃.

5. The production process for stably preparing quarter-hard copper strip according to claim 1, characterized in that: The annealing temperature in step (7) is 600 ℃ and the annealing rate is 35-40 m / min.

6. The production process for stably preparing quarter-hard copper strip according to claim 1, characterized in that: The annealing temperature in step (9) is 600 °C and the annealing rate is 60 m / min.

7. The production process for stably preparing quarter-hard copper strip according to claim 1, characterized in that: The straightening elongation rate in step (10) is 1.2-2.0%, and the straightening strength is 360 MPa.

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