A copper-chromium alloy and a method for producing and using the same

Abstract

The application discloses a copper-chromium alloy, which comprises the following components in percentage by mass: Cr 0.5%, Ce 0.05%, Fe 0.1%, Ni 0.05% and the balance of Cu and impurities. The application also discloses a preparation method of the copper-chromium alloy, which comprises the following steps: S1, melting of a master alloy; S2, hot rolling and intermediate heat treatment; and S3, cold rolling and intermediate heat treatment. The application further discloses a copper-chromium alloy cast-forged copper shoe prepared by the preparation method of the copper-chromium alloy.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-strength and high-conductivity copper alloy manufacturing, in particular to a copper-chromium alloy and a preparation method and application thereof. BACKGROUND

[0002] The copper tile is an electrical component and a mechanical component of the ore smelting furnace. The existing copper tile manufacturing materials mainly include oxygen-free copper, pure copper, bronze and brass. The surface temperature of the copper tile made of oxygen-free copper is the lowest, and the stress is small. The surface stress of the copper tile made of pure copper is the smallest, and the surface temperature is also low. The surface temperature of the copper tile made of brass and bronze is high, and the stress is also large. The cast copper tile has different liquidus temperature and solidus temperature during solidification, and has poor fluidity, large solidification shrinkage (4.5%-9%), and is prone to shrinkage holes. The shrinkage holes will cause the copper alloy casting to be unable to withstand water pressure and air pressure, the body cannot be sealed, the strength is reduced, especially the impact resistance and fatigue resistance are reduced, the surface roughness cannot meet the requirements, stress concentration is easy to occur, the shrinkage hole and air hole are easy to rust, and the texture is loose, which directly affects the conductivity. The cast copper tile will have problems such as block and layering during long-term service, stress concentration, and cracks, which will cause the copper tile to break, and the service life of the cast copper tile is short.

[0003] In order to overcome the above technical problems, people try to use high-strength and high-conductivity copper-chromium alloy materials to produce copper tiles. However, the traditional copper-chromium alloy preparation process is to add Cr, Ce and other elements on the basis of binary Cu-Cr in-situ composite material. In this process, the strength and conductivity matching degree of Cu-Cr autogenous composite material and the reasonable proportioning of Cr, Ce and other elements cannot be controlled and optimized, and finally the high-strength and high-conductivity Cu-Cr alloy material with physical properties and mechanical properties cannot be prepared.

[0004] Therefore, there is an urgent need for a copper-chromium alloy with excellent physical properties and mechanical properties. The copper tile for the ore smelting furnace is prepared by using the material to solve the problems of short service life and fracture of the copper tile under the traditional processing process. SUMMARY

[0005] In view of the above technical problems, the present application provides an internal forced stage type forage dry processing method.

[0006] In order to achieve the above purpose, the technical scheme of the present application is as follows:

[0007] A copper-chromium alloy, comprising the following components in mass percentage:

[0008] Cr 0.5%, Ce 0.05%, Fe 0.1%, Ni 0.05%, and the balance of Cu and impurities;

[0009] The impurities include S and P, wherein S is less than or equal to 0.0030% and P is less than or equal to 0.0030% by mass percentage.

[0010] The application further provides a preparation method of the copper-chromium alloy, comprising the following steps:

[0011] S1, melting of a master alloy

[0012] Cu, Cr, Ce, Fe and Ni are fed into a medium-frequency induction melting furnace for melting, and cast into an alloy ingot with a diameter of 730 mm in a graphite mold;

[0013] S2, hot rolling and intermediate heat treatment

[0014] The alloy ingot is subjected to homogenization treatment in an atmosphere protection furnace, and subjected to surface peeling processing, heat preservation, and surface peeling mechanical processing after hot rolling;

[0015] S3, cold rolling and intermediate heat treatment

[0016] The alloy ingot subjected to the step S2 is subjected to multiple cold rolling and intermediate heat treatment, and the surface oxide skin is removed after each intermediate heat treatment and before cold rolling.

[0017] The purity of the Cr is 99.94%, the purity of the Ce is 99.97%, the purity of the Fe is 99.95%, the purity of the Ni is 99.95%, and the Cu is selected as electrolytic copper with a purity of 99.97%.

[0018] In the step S1, the melting temperature is 1200-1350 DEG C.

[0019] In the step S2, the homogenization treatment temperature is 920 DEG C, the time is 2 hours, the surface peeling processing is to a diameter of 718 mm, the surface peeling mechanical processing after hot rolling is to a diameter of 701 mm, the heat preservation temperature is 850 DEG C, and the time is 20 minutes.

[0020] In the step S3, the specific implementation steps are as follows: cold rolling to a diameter of 233.7 mm, intermediate heat treatment at 450 DEG C for 30 minutes, removal of the surface oxide skin, secondary cold rolling to a diameter of 82 mm, intermediate heat treatment at 450 DEG C for 30 minutes, removal of the surface oxide skin, third cold rolling to a diameter of 31 mm, intermediate heat treatment at 450 DEG C for 20 minutes, removal of the surface oxide skin, and finally cold rolling to a diameter of 19 mm, intermediate heat treatment at 450 DEG C for 20 minutes.

[0021] The cold working deformation amount for removing the surface oxide skin is as follows:

[0022] ;

[0023] Wherein, A0 is the original cross-sectional area before cold working, A1 is the final cross-sectional area after cold working; η is 2.2-7.2.

[0024] Wherein, the deformation amount η is 4.2.

[0025] The application also provides a copper-chromium alloy cast-forged copper shoe prepared by the above copper-chromium alloy preparation method, the copper-chromium alloy, solid solution treatment, rapid water cooling, aging treatment and air cooling after being formed by forging and pressing.

[0026] Wherein, the solid solution treatment is heat preservation at 880-1020 ℃ for 30-60 min, rapid water cooling; the aging treatment is heat preservation at 450-490 ℃ for 0.5-5 h.

[0027] The application has the beneficial effects that: by adding Cr, Ce, Fe and Ni in a specific ratio, after plastic deformation and recrystallization treatment, the copper-chromium alloy has refined grains, uniform structure, effectively eliminates harmful precipitated phases in the copper-chromium alloy, and improves the comprehensive service performance of the copper-chromium alloy, the tensile strength and hardness of the copper-chromium alloy are obviously improved, it is an in-situ composite material with excellent wear resistance and oxidation resistance, and has good electrical conductivity, and the softening temperature resistance reaches 500 ℃; the copper shoe for the copper-chromium alloy is forged to solve the problems of block falling, layer rising and cracks of the existing copper shoe, and effectively improve the service life of the copper shoe. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is the microstructure diagram of Cu0.5Cr0.05Ce in experimental example 1 in embodiment 1 of the application, wherein (a)-(e) are the microstructure diagrams of the as-cast, forged and cold-rolled deformation amount η=2.2, 4.2 and 6.2, respectively;

[0029] Figure 2 is the microstructure scanning magnification diagram of Cu0.5Cr0.05Ce in experimental example 1 in embodiment 1 of the application, wherein (a)-(d) are the magnification diagrams of the as-cast, cold-rolled deformation amount η=4.2 and 6.2, respectively;

[0030] Figure 3 is the oxidation increment-time curve of three kinds of materials in experimental example 2 in embodiment 1 of the application;

[0031] Figure 4 is the dry friction three h scanning electron microscope diagram and magnification diagram of three kinds of materials in experimental example 3 in embodiment 1 of the application, wherein (a), (c) and (f) are the dry friction three h scanning electron microscope diagrams of the deformed Cu0.5Cr0.05Ce, the as-cast CuCr and red copper under the pressure of 400N and the linear speed of 1500mm / min; (b), (d) and (j) are the magnification diagrams of the deformed one in the experimental example, the as-cast CuCr and red copper, respectively.

[0032] Figure 5 is a hardness curve of Cu0.5Cr0.05Ce alloy under different deformation amounts in experimental example 4 in embodiment 1 of the present application with the change of heat treatment temperature and time;

[0033] Figure 6 is a conductivity curve of Cu0.5Cr0.05Ce under different casting processes in experimental example 4 in embodiment 1 of the present application with the change of heat treatment time and temperature. DETAILED DESCRIPTION

[0034] In order to make the objects, technical solutions and advantages of the present application clearer and more comprehensible, the present application will be further described in detail below with specific embodiments and with reference to the drawings. It should be understood that these descriptions are only exemplary and are not intended to limit the scope of the present application. In addition, in the following description, the description of the known structures and technologies is omitted to avoid unnecessary confusion of the concept of the present application.

[0035] Embodiment 1

[0036] A copper-chromium alloy, which is composed of the following raw material components by mass ratio:

[0037] Cr 0.5%, Ce 0.05%, Fe 0.1%, Ni 0.05% and the balance of copper and impurities.

[0038] Specifically, the impurities include S and P, wherein S≤0.0030% and P≤0.0030% by mass percentage.

[0039] Specifically, the steps of the copper-chromium alloy are:

[0040] (1) Master alloy smelting

[0041] Pure 99.97% electrolytic copper, 99.94% chromium, 99.97% cerium, 99.95% iron and 99.95% nickel are smelted in a medium-frequency induction smelting furnace, the smelting temperature is 1200-1350 ℃, and the alloy ingot of φ730 mm is cast in a graphite mold;

[0042] (2) Hot rolling and intermediate heat treatment

[0043] In an atmosphere protection furnace, homogenization treatment is carried out at a temperature of 920 ℃ for 2 h, and the surface is peeled to φ718 mm, and after hot rolling at 850 ℃ for 20 min, the surface is peeled and mechanically processed to φ701 mm;

[0044] (3) Cold rolling and intermediate heat treatment

[0045] Cu0.5Cr0.05Ce is obtained by cold rolling from φ701 mm to φ233.7 mm, intermediate heat treatment at 450 ℃ for 30 min, removing surface oxide, cold rolling to 82 mm for the second time, intermediate heat treatment at 450 ℃ for 30 min, removing surface oxide, cold rolling to 31 mm for the third time, intermediate heat treatment at 450 ℃ for 20 min, removing surface oxide, and finally cold rolling to 19 mm, intermediate heat treatment at 450 ℃ for 20 min.

[0046] Specifically, the cold working deformation amount for removing surface oxide is:

[0047]

[0048] wherein A0 is the original cross-sectional area before cold working, A1 is the final cross-sectional area after cold working; and η is 2.2-7.2.

[0049] Specifically, the cold working deformation amounts are and the corresponding diameters, respectively, according to the above formula:

[0050]

[0051] Experimental Example 1: Observation of Microstructure of Cu0.5Cr0.05Ce

[0052] The microstructure of the sample is observed by JSM-5700 scanning electron microscope, the etchant is 63% nitric acid solution, and after etching and rinsing, the sample is immersed in alcohol for ultrasonic cleaning; metallographic observation is performed, and the etchant is 40 ml distilled water+25 mL ammonia water+10 ml hydrogen peroxide. The room temperature tensile test of the sample is performed on a liquid crystal electronic tensile testing machine, and the tensile rate is 1.510-4. The conductivity test is measured by D60 digital metal conductivity measuring instrument.

[0053] 1.1 Metallographic structure of Cu0.5Cr0.05Ce

[0054] As shown in Figure 1 (a)-(e) are microstructure diagrams of Cu0.5Cr0.05Ce in as-cast, as-forged, and cold rolling deformation amounts of η=2.2, 4.2, and 6.2, respectively. As can be seen from the metallographic structure, the as-cast structure shows dendritic distribution, and with the increase of deformation amount, Cr phase forms fibrous structure, and the greater the deformation amount, the finer the Cr fiber, and the better the fiber strengthening.

[0055] 1.2 Scanning structure of Cu0.5Cr0.05Ce

[0056] As shown in Figure 2 ​(a), (b), (c), (d) are as-cast, cold-rolled deformation amount of η = 4.2, 6.2 and the enlarged view of Cu0.5Cr0.05Ce respectively. From the figure, the microstructure evolution law of Cr fibers can be obviously seen. With the increase of deformation amount, the more Cr fiber phase is formed and the more the microstructure is refined.

[0057] 1.3 Performance test results of Cu0.5Cr0.05Ce

[0058] Table 1 Performance results of Cu0.5Cr0.05Ce under different deformation amounts

[0059]

[0060] From Table 1, it can be seen that with the increase of deformation amount, the tensile strength and hardness increase, while the electrical conductivity decreases. When the deformation amount reaches η = 4.2, the tensile strength and electrical conductivity have the best matching relationship, that is, the electrical conductivity is 73% IACS and the tensile strength is 810 MPa.

[0061] Experimental Example 2 Oxidation resistance experiment of Cu0.5Cr0.05Ce

[0062] 2.1 Oxidation resistance experiment process of Cu0.5Cr0.05Ce

[0063] The experimental materials are heavily deformed Cu0.5Cr0.05Ce, as-cast Cu14.5Cr and red copper. No. 1 is a red copper material, and No. 2 and No. 3 are as-cast Cu14.5Cr and Cu0.5Cr0.05Ce developed by ourselves. All the samples are processed into 7 mm 15 mm 40 mm plate-shaped samples. The standard weight gain method is used for oxidation resistance performance experiment. The size of the weighed sample is 5 mm 10 mm 30 mm, the test temperature is selected as 400 ℃, the holding time is 250 h, and the weighing time interval is selected as 50 h, 100 h, 150 h, 200 h and 250 h. The average unit area oxidation increment value of 3 groups of samples is used to draw the oxidation kinetics curves of the 3 materials.

[0064] The surface oxide layer morphology of the samples after oxidation is observed by optical metallographic microscope, and the density of the material is measured by hydrostatic method. The oxide phase structure of the alloy surface layer is analyzed by D500X ray diffractometer. The X-ray diffraction experimental parameters are as follows: copper target is used, graphite crystal monochromator, X-ray tube high voltage is 40 kV, tube flow is 30 mA, diffraction angle is 20 b-100 b, scintillation counter is used for recording, and computer control automatic measurement is used.

[0065] 2.2 Oxidation resistance experiment results of Cu0.5Cr0.05Ce

[0066] 2.2.1 Oxidation increment-time curves of the three materials

[0067] Depend on Figure 3 It can be seen that the oxidation rate of the three materials increases with the increase of temperature. In the range of 50-100 h, the growth of oxide films of the three alloys basically follows a linear change law. However, in the range of 100-250 h, the growth curves of the oxide films of copper and cast Cu14.5Cr increase sharply, while the growth of the oxide film of Cu0.5Cr0.05Ce is slow and no deep oxidation occurs.

[0068] 2.2.2 Antioxidant properties of various materials

[0069] Table 2 shows the antioxidant properties of different materials.

[0070]

[0071] As can be seen from Table 2, Cu0.5Cr0.05Ce exhibits strong antioxidant capacity.

[0072] Experimental Example 3: Wear Resistance Test of Cu0.5Cr0.05Ce

[0073] 3.1 Tribological Procedure of Cu0.5Cr0.05Ce

[0074] The experimental materials were copper, as-cast Cu14.5Cr, and large-deformation Cu0.5Cr0.05Ce. After being smelted in an induction furnace, they were cast into ingots and then processed into Cu0.5Cr0.05Ce (deformation amount η=4.2) through a large-deformation process. Finally, they were processed into an experimental φ8×30mm friction upper sample and a Q235 low-carbon steel lower sample.

[0075] The wear performance and friction coefficient of the samples were determined using an RFF-III reciprocating friction and wear tester (pressure 400 N, linear speed 1500 mm / min, dry friction for 3 h). The wear track morphology of the samples when different materials were rubbed against Q235 low carbon steel under dry friction conditions was observed using a JSM-6700F scanning electron microscope.

[0076] 3.2 Experimental Results of Friction Morphology of Cu0.5Cr0.05Ce

[0077] Figure 4 (a) Figure 4 (c) Figure 4 (f) are scanning electron microscope images of deformed Cu0.5Cr0.05Ce, cast CuCr, and copper under dry friction for three hours at a pressure of 400N and a linear velocity of 1500mm / min, respectively. Figure 4 (b) Figure 4 (d) Figure 4(j) are enlarged view of deformed Cu0.5Cr0.05Ce, as-cast CuCr, red copper respectively. From the friction morphology, it can be seen that the deformed Cu0.5Cr0.05Ce has the densest structure, and the adhesion wear is dominant, so it has the best wear resistance. The as-cast Cu14.5Cr has the loosest structure, and the abrasive wear is dominant, so it has the poor wear resistance. The red copper has the worst wear resistance. From the 50 times enlarged view, the wear surface is smooth, so it is considered to have the best wear resistance. However, from the 500 times enlarged view, it can be seen that the wear is mainly the flaky exfoliation wear, and the wear amount is large, so the sample is worn out.

[0078] 3.3 Experimental results of Cu0.5Cr0.05Ce friction performance

[0079] Table 3 Friction performance

[0080]

[0081] From Table 3, it can be seen that the Cu0.5Cr0.05Ce has the best friction and wear performance compared with the other two materials. The Cu0.5Cr0.05Ce mainly has the adhesion wear, so it has the good friction performance. The heat-treated as-cast Cu14.5Cr mainly has the abrasive wear, so it has the second friction performance. The red copper has the worst friction performance, and mainly has the flaky exfoliation wear.

[0082] Experimental Example 4 Cu0.5Cr0.05Ce solid solution-aging experiment

[0083] 4.1 Experimental process of solid solution-aging experiment

[0084] CuCr0.9 was melted in a ZGJL010-49-4 type vacuum induction furnace, and the melting temperature was 1200°C or 1350°C. After the raw material was melted, it was stirred sufficiently, and then was processed into Cu0.5Cr0.05Ce with a deformation amount of η=4.2 and η=6.2. The sample was cut into a size of 20 mm×20 mm×20 mm by wire cutting. The sample was subjected to solid solution-aging treatment by using an RJX-2.5-10 type box resistance furnace, and the solid solution temperature was 880°C, 900°C, 920°C and 940°C respectively, the solid solution time was 1h, and the sample was rapidly cooled by using salt water. The aging temperature was 450°C, and the aging time was 0.5h, 1h, 1.5h, 2h, 2.5h, 3.5h and 4h respectively. The Brinell hardness and conductivity of the sample were measured by using a HBE-3000A type hardness tester and a D60k digital metal conductivity measuring instrument respectively.

[0085] 4.2 Experimental results of solid solution-aging experiment

[0086] As Figure 5 (a), Figure 5(b) are hardness change curves of Cu0.5Cr0.05Ce after different temperature solid solution treatment and aging, respectively. The hardness change rules of Cu0.5Cr0.05Ce under two deformations are basically the same. The hardness of the alloy increases first, reaches a peak value and then decreases after a period of aging treatment. When the solid solution temperature is 880 ℃ and the aging temperature is 450 ℃, the hardness does not have an obvious peak value. When the solid solution temperature is 900 ℃-940 ℃ and the aging temperature is 450 ℃, the hardness increases first, reaches a peak value and then decreases after a period of aging, and the higher the solid solution temperature, the more obvious the hardness decrease trend. The hardness of Cu0.5Cr0.05Ce under deformation η=6 is higher than that under deformation η=4.2. After solid solution and aging at 450 ℃ for 1.5 h, the peak hardness value of Cu0.5Cr0.05Ce under deformation η=6 is 135 HRB. After solid solution and aging at 450 ℃ for 2 h, the peak hardness value of Cu0.5Cr0.05Ce under deformation η=4.2 is 124 HRB.

[0087] As Figure 6 (a), Figure 6 (b) are conductivity change curves of Cu0.5Cr0.05Ce after different temperature solid solution treatment and aging, respectively. The conductivity change curves of Cu0.5Cr0.05Ce after different temperature solid solution treatment and aging under different deformations. As can be seen from the figure, the conductivity change curves of Cu0.5Cr0.05Ce under two deformations have the same trend. The conductivity increases sharply at first, reaches a platform and then increases slowly with the extension of aging time. The higher the solid solution temperature, the shorter the time required to reach the platform during the aging process, and the higher the conductivity value corresponding to the platform. The conductivity under deformation η=4 is much higher than that under deformation η=6. After solid solution at 920 ℃ and aging at 450 ℃ for 1.5 h, the conductivity value under deformation η=4 is 73 IACS. After solid solution at 920 ℃ and aging at 450 ℃ for 2 h, the conductivity value under deformation η=6 is 64.2 IACS.

[0088] It can be seen that the optimal intermediate heat treatment process is solid solution at 920 ℃ for 1 h and aging at 450 ℃ for 2 h. According to the above experimental results, the deformation amount is selected as η=4.2, and the conductivity and hardness experimental results are the best.

[0089] Example 2

[0090] The embodiment provides a copper-chromium alloy cast-forged copper shoe prepared by the method of preparing the copper-chromium alloy in Example 1, and the copper-chromium alloy is formed by forging and pressing, then subjected to solid solution treatment, rapid water cooling, aging treatment and air cooling.

[0091] Specifically, the solid solution treatment is water cooling after holding at 880 DEG C for 30 min; the aging treatment is holding at 450 DEG C for 0.5 h.

[0092] Embodiment 3

[0093] The embodiment provides a copper-chromium alloy cast-forged copper shoe, which is prepared by adopting the preparation method of the copper-chromium alloy in Embodiment 1, and is formed by forging and pressing, and then is subjected to solid solution treatment, rapid water cooling, aging treatment and air cooling.

[0094] Specifically, the solid solution treatment is water cooling after holding at 880 DEG C for 30 min; the aging treatment is holding at 450 DEG C for 0.5 h.

[0095] The above merely describes the preferred embodiments of the present application, but not used to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A copper-chromium alloy, characterized in that, Comprise the following components by mass percentage: Cr 0.5%, Ce 0.05%, Fe 0.1%, Ni 0.05% and the balance of Cu and impurities; The impurities include S, P, wherein, by mass percentage, S≤0.0030%, P≤0.0030%; The preparation method of the copper-chromium alloy comprises the following steps: S1, master alloy smelting Cu, Cr, Ce, Fe and Ni are sent into a medium-frequency induction smelting furnace for smelting, and φ730 mm alloy ingot is cast in a graphite mold; S2, hot rolling and intermediate heat treatment The alloy ingot is subjected to homogenization treatment in an atmosphere protection furnace, and surface peeling processing is performed, heat preservation is performed, and surface peeling mechanical processing is performed after hot rolling; S3, cold rolling and intermediate heat treatment The alloy ingot after step S2 is subjected to multiple cold rolling and intermediate heat treatment, and the surface oxide skin is removed after each intermediate heat treatment and before cold rolling; In step S3, the specific implementation steps are: cold rolling to φ233.7 mm, intermediate heat treatment at 450 ℃ for 30 min, removing the surface oxide skin, cold rolling to φ82 mm, intermediate heat treatment at 450 ℃ for 30 min, removing the surface oxide skin, cold rolling to φ31 mm, intermediate heat treatment at 450 ℃ for 20 min, removing the surface oxide skin, and finally cold rolling to φ19 mm, intermediate heat treatment at 450 ℃ for 20 min; When the copper-chromium alloy is used for casting and forging copper shoes, the copper shoes are formed after forging and pressing, solid solution treatment, rapid water cooling, aging treatment and air cooling; The solid solution treatment is heat preservation at 880-1020 ℃ for 30-60 min, and rapid water cooling; the aging treatment is heat preservation at 450-490 ℃ for 0.5-5 h.

2. The method of claim 1, wherein the copper-chromium alloy is prepared by the steps of: The purity of Cr is 99.94%, the purity of Ce is 99.97%, the purity of Fe is 99.95%, the purity of Ni is 99.95%, and the purity of Cu is 99.97% electrolytic copper.

3. The method for preparing a copper-chromium alloy according to claim 1, characterized in that, In step S1, the smelting temperature is 1200-1350 ℃.

4. The method for preparing a copper-chromium alloy according to claim 1, characterized in that, In step S2, the homogenization treatment temperature is 920 ℃, and the time is 2 h; the surface peeling processing is to φ718 mm, and the surface peeling mechanical processing after hot rolling is to φ701 mm; the heat preservation temperature is 850 ℃, and the time is 20 min.

5. The method for preparing a copper-chromium alloy according to claim 1, characterized in that, The surface oxide skin removal cold working deformation amount is: ； Wherein, A0 is the original cross-sectional area before cold working, A1 is the final cross-sectional area after cold working; η is 2.2-7.

2.

6. A method of producing a copper-chromium alloy according to claim 5, characterized in that, The deformation amount η is 4.

2.

7. A copper-chromium alloyed cast-forged copper shoe characterized by, The copper-chromium alloy is prepared by the preparation method of any one of claims 1-6. The copper-chromium alloy is prepared by the preparation method of any one of claims 1-6.

Images