Red copper thick plate and preparation method thereof

Abstract

The invention relates to a red copper thick plate and a preparation method thereof. The preparation method comprises the steps of smelting, casting, hot rolling, online quenching, cold rolling, finished product annealing, sampling detection, finished product sawing and packaging and warehousing. In the smelting process, Cu-La intermediate alloy is added, and the adding amount is 5-200 ppm; in the hot rolling process, the finish rolling temperature is controlled to be larger than or equal to 600 DEG C, rapid cooling is conducted after hot rolling, and online quenching solid solution is achieved; and when a finished product is annealed, the annealing temperature is controlled to be 200-450 DEG C, the time is 5-8 hours, and a protective atmosphere is adopted. According to the method, the problem of coarse grains of the soft red copper thick plate is solved, the fine and uniform soft red copper thick plate is obtained through a process test, and a good effect is achieved in application practice; the problem that the production difficulty of the products is large is solved, batch production can be achieved, and the industrial production target is achieved.

Description

Technical Field

[0001] The invention belongs to the field of nonferrous metal smelting and processing, and in particular relates to a thick copper plate and a preparation method thereof. Background Art

[0002] The armor-piercing projectile, which mainly relies on metal jets to penetrate armor, uses copper as the material of the liner. Its basic principle is the Monroe effect, that is, the explosive energy-gathering effect. After a conical hole is opened on the explosive column and the liner is installed, the detonation wave of the explosive detonation converges, which can gather the liner into a metal jet with extremely high speed and temperature, penetrating the armor like a high-pressure water gun hitting a mud wall. Although the metal jet generated in the detonation has a liquid-like fluidity in a high-speed environment, it is actually still solid. The liner material should be a metal with good ductility and high density. The material that takes into account the performance and cost of the liner is copper. It has moderate ductility, low price, and is easy to process. After a long period of research, it is currently a more mature material.

[0003] The penetration depth of armor-piercing projectiles is related to the density of the liner material. The higher the density, the better the ductility and the better the jet performance. The commonly used liner copper plate specifications are 10×600×(1000~1500)mm, which not only affects the purity of the plate and the mechanical properties of the soft state (R m ≥205MPa, A 11.3 ≥42%), and the copper grains are required to be uniform and fine, with a grain size of 0.01-0.03mm. The more uniform and fine the grains, the higher the copper purity, the greater the density, and the better the ductility.

[0004] However, during the preparation of this soft thick plate, the higher the copper purity, the easier it is for the grains to grow during annealing; plus the finished product is thicker and has uneven deformation in height, so it is very easy for large and uneven grains to appear during annealing of the finished product, affecting subsequent use. Summary of the invention

[0005] The object of the present invention is to provide a red copper thick plate and a preparation method thereof, so that the prepared red copper thick plate has uniform and fine grain size maintained at 0.01-0.03mm under the condition of qualified soft state performance, and meets the subsequent use requirements.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is: a method for preparing a thick copper plate, comprising the following steps: S1, preheating the cathode copper with pure surface, removing the moisture attached to the surface, melting it into copper liquid in a furnace, and covering it with calcined charcoal or carbon black; S2, the copper liquid is left to stand and deoxidized by calcined charcoal or carbon black to obtain an oxygen-free copper melt, and then a certain amount of Cu-La master alloy is added; S3, using the molten metal obtained in S2 to perform casting, and covering and protecting the melt in the crystallizer during casting; S4, sawing the ingot obtained in S3 according to the required length on a sawing machine; S5, heating the ingot after sawing in S4 by using a heating furnace, the heating temperature is 700-850°C, the heating time is 1.0-3.0 hours, and the ingot is evenly heated and then taken out of the furnace; S6, hot rolling is carried out after the ingot is heated and taken out of the furnace, the total processing rate of the hot-rolled strip is ≥90%, the final rolling temperature is ≥600°C, and online quenching and solid solution are carried out immediately after hot rolling; S7, sawing the hot-rolled strip according to the finished product length, and taking samples at different length positions to detect the grain size; S8, cold rolling the hot-rolled strip obtained by the process in S7 to the finished product thickness; S9, performing finished annealing heat treatment on the plate after cold rolling in S8, the annealing temperature is 200-450°C, the time is 5-8 hours, and a protective atmosphere is used during the annealing, and the gas content is: hydrogen 75%, and the rest is nitrogen; S10. Take samples of the annealed plates and conduct performance tests. The qualified finished plates are sawn according to the size requirements, packaged and put into storage.

[0007] As an implementation mode, in step S2, the addition amount of the Cu-La master alloy is 5-200 ppm, and the Cu-La master alloy is prepared using grade A copper as raw material.

[0008] The grade A copper is in accordance with GB / T467-2010.

[0009] Furthermore, in step S2, the addition amount of the Cu-La master alloy is 20-180 ppm, and the Cu-La master alloy is prepared using high-purity La with a La purity of 3N or above as a raw material.

[0010] The high-purity La with a La purity of 3N or above is based on the standard of GB / T15677-2023.

[0011] As an embodiment, in step S5, the heating temperature is 730-850°C, and the heating time is 1.5-3.0 hours.

[0012] As an implementation mode, in step S6, the cooling time is 3-5 minutes, and after cooling to room temperature, the surface color of the plate after online quenching and solutionizing is purple-red.

[0013] As an embodiment, in step S6, the final rolling temperature is ≥ 650°C.

[0014] As an implementation mode, in step S6, the final rolling temperature is ≥ 680°C.

[0015] As an implementation mode, in step S9, the annealing temperature is 220-400°C.

[0016] As an implementation mode, in step S9, the annealing temperature is 280-380°C.

[0017] The present invention also provides a copper thick plate, which is prepared by the above preparation method, and the grain size of the plate is 0.01-0.03mm, the tensile strength Rm≥205Mpa, and the elongation A 11.3 ≥42%.

[0018] The technical principle and beneficial effect of the present invention are as follows: according to the above technical scheme, in the preparation of the soft thick plate fine grain of copper, due to the addition of Cu-La master alloy to the melt in step S2, La and impurities such as O, P and other submicron-level spherical compounds are formed, which improve the strength and purify the matrix to improve the purity of copper; the plate after hot rolling is subjected to online quenching and solid solution (rapid cooling) to maintain the uniform and fine grain size after hot rolling and the solid solution effect of La; during cold rolling, cross rolling along different directions of the plate and appropriate aging and recrystallization annealing process are performed, so that the nano-level La-rich phase plays a pinning role on the grain boundary during the annealing and aging process, increases the driving force required for grain boundary migration, and thus inhibits the growth of recrystallized grains.

[0019] The present invention solves the problem of coarse grains of soft copper thick plates, obtains fine and uniform soft copper thick plates through process tests, and achieves good results in practical application; solves the problem of difficulty in producing such products, can achieve batch output, and realize the goal of industrialized production. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below in conjunction with embodiments and comparative examples, but they are not intended to limit the invention in any way.

[0021] Embodiment 1: A method for preparing a thick copper plate comprises the following steps: (1) Smelting: Select cathode copper with a copper content of 99.993% as the raw material for preheating, remove the water attached to the surface, put it into the furnace to melt it into copper liquid, and cover it with calcined charcoal; after the copper liquid is left to stand for a period of time and deoxidized by charcoal, an oxygen-free copper melt is obtained, and then Cu-La master alloy is added, and the Cu-La master alloy addition amount is 5.5ppm; (2) Casting and sawing: Casting is carried out after the melt is uniform. During casting, carbon black or protective gas is used to cover the melt in the crystallizer to obtain an ingot with a specification of 170×620mm. The ingot is sawed on a sawing machine according to the required length and inspected and repaired. (3) Ingot heating: The ingot is heated by a walking beam heating furnace at a temperature of 710°C for 3.0 hours; (4) Hot rolling: Ingot hot rolling is carried out on hot rolling equipment, with 9 passes, final rolling temperature of 605°C, and a total processing rate of 90%; (5) Cooling: After hot rolling, use an online cooling device to perform online quenching and solution treatment, rapid cooling, and the cooling time is controlled within 3-5 minutes to cool to room temperature; (6) Cold rolling: using a cold rolling mill to roll in different directions to the finished product thickness, with a processing rate of 7-12% per pass and a total processing rate of 60%; (7) Finished product annealing: Place the cold-rolled plate in a material frame, the middle of the material frame is connected to the fan of the annealing furnace base, and annealing is carried out in a hood-type annealing furnace. The loading capacity of each furnace shall not exceed 3.5 tons, and the furnace temperature uniformity shall be guaranteed to be ±5°C. The annealing temperature is 200°C and the time is 8 hours; (8) Sampling and testing: Take mechanical property and grain size samples from the plate body one by one, make the samples according to the standards, and then use electronic tensile testing machine and electron microscope for testing. After the mechanical properties and grain size meet the requirements, the finished products are sawn; (9) Finished product sawing: Use precision saws to ensure sawing accuracy; (10) Packaging and warehousing: Finished products are packaged and stored after passing inspection.

[0022] When sampling and testing, tensile strength Rm, elongation A 11.3 According to GB / T-228.1-2021 standard, the test is carried out using an electronic tensile testing machine, and the grain size is detected by an electron microscope in accordance with YS / T347-2020 standard.

[0023] Embodiment 2: The difference between this embodiment and embodiment 1 is that: (1) The copper content of cathode copper used for smelting is 99.995%; (2) The addition amount of Cu-La master alloy is 20.8ppm; (3) The hot rolling temperature is 750°C, the holding time is 2.8h; the hot rolling final rolling temperature is 630°C; (4) Finished product annealing temperature 220°C, annealing time 7.3h; The other steps are the same as those in Example 1.

[0024] Embodiment 3: The difference between this embodiment and embodiment 1 is that: (1) The copper content of cathode copper used for smelting is 99.995%; (2) The addition amount of Cu-La master alloy is 62ppm; (3) The hot rolling temperature is 830°C, the holding time is 2.5h; the hot rolling final rolling temperature is 665°C; (4) Finished product annealing temperature is 300°C and annealing time is 6h; The other steps are the same as those in Example 1.

[0025] Embodiment 4: This embodiment differs from Embodiment 1 in that: (1) The copper content of cathode copper used for smelting is 99.994%; (2) The addition amount of Cu-La master alloy is 174ppm; (3) The hot rolling temperature is 850°C, the holding time is 2.0h; the hot rolling final rolling temperature is 678°C; (4) Finished product annealing temperature 400°C, annealing time 5.5h; The other steps are the same as those in Example 1.

[0026] Embodiment 5: The difference between this embodiment and embodiment 1 is that: (1) The addition amount of Cu-La master alloy is 95ppm; (2) The hot rolling temperature is 850°C, the holding time is 2.3h; the hot rolling final rolling temperature is 682°C; (3) Finished product annealing temperature 400°C, annealing time 5.0h; The other steps are the same as those in Example 1.

[0027] Example 6: The present invention provides a soft copper thick plate, which is prepared by the method described in Examples 1-5, wherein the grain size and tensile strength R m , elongation A 11.3 See Table 1 for details.

[0028] The present invention also designs comparative examples 1-5 below to demonstrate the technical effect of the method described in the present invention.

[0029] Comparative Example 1: In Comparative Example 1, the copper content of the cathode copper is 99.994%, the addition amount of Cu-La master alloy in the smelting process is 22ppm, and the process parameters of hot rolling and finished product annealing are as follows: (1) Hot rolling: temperature 720°C, holding time 3.0h, final rolling temperature 550°C, the final rolling temperature is lower than the range required by the present invention; (2) Finished product annealing: annealing temperature 220℃, annealing time 9h.

[0030] The other steps are the same as those in Example 2.

[0031] Comparative Example 2: In Comparative Example 2, the copper content of the cathode copper is 99.994%, the addition amount of Cu-La master alloy in the smelting process is 88ppm, and the process parameters of hot rolling and finished product annealing are as follows: (1) Hot rolling: temperature 850°C, holding time 2.0h, final rolling temperature 680°C; (2) Finished product annealing: annealing temperature 460°C, annealing time 5h.

[0032] The other steps are the same as those in Example 4.

[0033] Comparative Example 3: In Comparative Example 3, the copper content of the cathode copper is 99.994%, no Cu-La master alloy is added during the smelting process, and the process parameters of hot rolling and finished product annealing are as follows: (1) Hot rolling: temperature 720°C, holding time 3.0h, final rolling temperature 623°C; (2) Finished product annealing: annealing temperature 200°C, annealing time 9h.

[0034] The other steps are the same as those in Example 2.

[0035] Comparative Example 4: In Comparative Example 4, the copper content of the cathode copper is 99.995%, no Cu-La master alloy is added during the smelting process, and the process parameters of hot rolling and finished product annealing are as follows: (1) Hot rolling: temperature 830°C, holding time 1.0h, final rolling temperature 660°C; (3) Finished product annealing: annealing temperature 400°C, annealing time 5.5h.

[0036] The other steps are the same as those in Example 4.

[0037] Comparative Example 5: In Comparative Example 5, the copper content of the cathode copper is 99.994%, the amount of Cu-La master alloy added during the smelting process exceeds the range required by the present invention, and the process parameters of hot rolling and finished product annealing are also different from those of Example 1. Edge cracking occurs during hot rolling, and the processing is difficult. The amount of Cu-La master alloy added and the process parameters of hot rolling are as follows: (1) The addition amount of Cu-La master alloy is 218ppm; (2) Hot rolling: temperature 850°C, holding time 2.5h, final rolling temperature 705°C; (3) Finished product annealing: annealing temperature 400°C, annealing time 5.5h.

[0038] The other steps are the same as those in Example 1.

[0039] The method and product test results of the above Examples 1-5 and Comparative Examples 1-5 are shown in Table 1.

[0040] Table 1 Methods and product test results of the embodiments and comparative examples From Table 1 we can see that: 1. In Examples 1-5, due to the addition of La, the guarantee of the final rolling temperature during hot rolling (effective online solid solution can be achieved) and the control of the finished product annealing process, not only the properties of the copper thick plate are controlled within the qualified range (R m≥205MPa, A 11.3 ≥42%), and the grain size is also controlled at 0.01-0.03mm, keeping it small and uniform.

[0041] 2. Comparative Example 1 contains La similar to that in Example 2. Since the final rolling temperature of the strip during hot rolling is relatively low (less than 600°C), La cannot be fully dissolved in the matrix and is randomly distributed after annealing of the finished product. It cannot play a significant pinning role on the grain boundaries, resulting in uneven grain size of the finished product and locally grown grains.

[0042] 3. Comparative Example 2 contains La similar to that in Example 4, but because the finished product annealing temperature is too high (460°C), the plate still has energy after complete recrystallization, the grains begin to grow (between 0.045-0.06mm), and the material strength begins to decrease (192MPa), which is lower than the required standard.

[0043] 4. Comparative Example 3-4 does not include La: (1) In Comparative Example 3, the hot rolling process is similar to that of Example 2 and meets the requirements of the present invention. In order to ensure that the final grain size is qualified, a lower finished product annealing temperature is used. Although the grain size of the finished plate reaches the required upper limit of 0.03 mm, its elongation is 41%, which is lower than the required 42%. This indicates that the material has begun to recrystallize but has not been completely completed, so the microscopic stress inside the material has not been completely eliminated, and some grains have begun to grow before the elongation performance reaches a good level.

[0044] (2) In comparative example 4, the annealing process is the same as that of example 4 during the annealing of the finished product, and the holding time of the ingot heating is shortened to reduce the energy storage during the holding process and the grain growth during hot rolling. However, the grain size of the final finished plate is uneven, and most samples exceed the standard requirements.

[0045] Comparative Examples 3 and 4 are both in line with the normal copper grain size growth law during annealing. The power required for copper grain boundary migration is relatively small, and it is easy to engulf each other and grow after recrystallization.

[0046] 5. In Comparative Example 5, although the grain size of the sample after sampling meets the requirements of the present invention, due to the large amount of La added, hot rolling cracking occurred during the preparation process, making the processing process difficult. This is because when the La content in copper is too high, the high-temperature plasticity of the ingot deteriorates, and the strip is prone to cracking during hot rolling.

[0047] Through the above embodiments and comparative examples, it can be explained that the present invention effectively solves the problem that the grains of the soft and thick copper plate are easy to grow or are uneven, and meets the needs of users.

[0048] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the same. Those skilled in the art should understand that the specific implementation modes of the present invention may be modified or replaced by equivalents with reference to the above embodiments. Any modifications or equivalent replacements that do not depart from the spirit and scope of the present invention are within the scope of protection of the pending claims.

Claims

1. A method for preparing a thick copper plate, characterized in that: The steps include: S1, preheating the cathode copper with pure surface, removing the moisture attached to the surface, melting it into copper liquid in a furnace, and covering it with calcined charcoal or carbon black; S2, the copper liquid is left to stand and deoxidized by calcined charcoal or carbon black to obtain an oxygen-free copper melt, and then a certain amount of Cu-La master alloy is added; S3, using the molten metal obtained in S2 to perform casting, and covering and protecting the melt in the crystallizer during casting; S4, sawing the ingot obtained in S3 according to the required length on a sawing machine; S5, heating the ingot after sawing in S4 by using a heating furnace, the heating temperature is 700-850°C, the heating time is 1.0-3.0 hours, and the ingot is evenly heated and then taken out of the furnace; S6, hot rolling is carried out after the ingot is heated and taken out of the furnace, the total processing rate of the hot-rolled strip is ≥90%, the final rolling temperature is ≥600°C, and online quenching and solid solution are carried out immediately after hot rolling; S7, sawing the hot-rolled strip according to the finished product length, and taking samples at different length positions to detect the grain size; S8, cold rolling the hot-rolled strip obtained by the process in S7 to the finished product thickness; S9, performing finished annealing heat treatment on the plate after cold rolling in S8, the annealing temperature is 200-450°C, the time is 5-8 hours, and a protective atmosphere is used during the annealing, and the gas content is: hydrogen 75%, and the rest is nitrogen; S10. Take samples of the annealed plates and conduct performance tests. The qualified finished plates are sawn according to the size requirements, packaged and put into storage.

2. The method for preparing a thick copper plate according to claim 1, characterized in that: In step S2, the addition amount of the Cu-La master alloy is 5-200 ppm, and the Cu-La master alloy is prepared using grade A copper as a raw material.

3. The method for preparing a thick copper plate according to claim 2, characterized in that: In step S2, the addition amount of the Cu-La master alloy is 20-180 ppm, and the Cu-La master alloy is prepared using high-purity La with a La purity of 3N or above as a raw material.

4. The method for preparing a thick copper plate according to claim 1, characterized in that: In step S5, the heating temperature is 730-850°C and the heating time is 1.5-3.0 hours.

5. The method for preparing a thick copper plate according to claim 1, characterized in that: In step S6, the cooling time is 3-5 minutes, and the plate is cooled to room temperature. The surface color of the plate after online quenching and solution treatment is purple-red.

6. The method for preparing a thick copper plate according to claim 1, characterized in that: In step S6, the final rolling temperature is ≥ 650°C.

7. The method for preparing a thick copper plate according to claim 1, characterized in that: In step S6, the final rolling temperature is ≥ 680°C.

8. The method for preparing a thick copper plate according to claim 1, characterized in that: In step S9, the annealing temperature is 220-400°C.

9. The method for preparing a thick copper plate according to claim 1, characterized in that: In step S9, the annealing temperature is 280-380°C.

10. A thick copper plate, characterized in that: The plate is prepared by the preparation method according to any one of claims 1 to 9, wherein the grain size of the plate is 0.01-0.03 mm, the tensile strength Rm ≥ 205 MPa, and the elongation A 11.3 ≥42%.

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