Copper alloy and preparation method and application thereof

Abstract

The invention provides a copper alloy and a preparation method and application thereof, and belongs to the technical field of alloys. The copper alloy disclosed by the invention comprises the following elements in percentage by mass: 2-3% of Ni, 0.1-1.5% of Cr, 0.2-1% of Mn, 0.05-0.2% of rare earth elements and the balance of Cu and inevitable impurities. Wherein the rare earth element is La or Ce. By adding a small amount of Ni and rare earth elements, the high-temperature comprehensive mechanical property and stress corrosion resistance of the copper alloy are improved, and the copper alloy is suitable for high-temperature wear-resistant stress corrosion-resistant occasions such as continuous casting and rolling casting machine crystallizers.

Description

Technical Field

[0001] The present disclosure relates to the technical field of copper alloys, and in particular to a copper alloy and a preparation method and application thereof. Background Art

[0002] Copper alloy is one of the main materials of crystallizer. It faces the erosion of high-temperature molten metal during service and needs to have higher high-temperature wear resistance. The crystallizer generally needs water cooling or graphite spraying on the surface to facilitate demolding of the casting. The crystallizer as a structural part is prone to stress corrosion cracking under such working conditions. Therefore, the copper alloy used for the crystallizer is required to have higher stress corrosion resistance.

[0003] At present, the mainstream copper alloys for crystallizers include Cu-Cr-Zr, Cu-Ag, Cu-Ni-Si, etc. All of the above copper alloys are precipitation-strengthened copper alloys, which can meet the high-strength and high-conductivity requirements of electronic and electrical products such as lead frames and electrical contact parts. The operating temperature of the above electronic and electrical products is relatively low, and there is no stress corrosion failure. However, the main strengthening principle of precipitation-strengthened copper alloys is precipitation strengthening and work hardening of the precipitated phase. When applied to crystallizers with higher operating temperatures, physical and chemical changes such as aging and annealing will occur during the service process, resulting in a decrease in the strength of the copper alloy. In addition, the complex chemical corrosion environment will eventually cause stress corrosion cracking of the crystallizer.

[0004] At present, copper alloys with high comprehensive performance are mainly obtained by adding different elements or changing the preparation method of copper alloys. For example, patent CN106916996A improves the low-temperature comprehensive mechanical properties and wear resistance of copper alloys by adding elements such as manganese, zinc, titanium, iron, and chromium. However, its thermal conductivity is poor and does not meet the use requirements of the crystallizer; patent CN106916996A improves the comprehensive mechanical properties of copper alloys at 300°C through vacuum casting, homogenization treatment, solution treatment, cold rolling and aging treatment. Since the copper alloy adopts cold deformation during the processing process, long-term service at high temperature is likely to cause more obvious annealing of the copper alloy. In addition, the residual cold deformation texture reduces the stress corrosion resistance of the copper alloy.

[0005] Therefore, the development of a high-temperature, wear-resistant and stress-corrosion-resistant copper alloy is of great significance for improving the service life of the crystallizer, saving copper resources, and avoiding production accidents caused by stress corrosion cracking of the crystallizer. Summary of the invention

[0006] The purpose of the present disclosure is to overcome the deficiencies of the prior art and provide a copper alloy and a preparation method and application thereof. At a temperature of 350°C, the copper alloy has a tensile strength of ≥450MPa, an elongation of ≥10%, an electrical conductivity of ≥42%IACS, and a hardness of ≥130HV; and under conditions of an ammonia ion concentration of 1mol / L and a torque of 78Nm, the copper alloy has a fracture time of ≥36h.

[0007] To achieve the above-mentioned purpose, the technical solution adopted by the present disclosure is as follows: in the first aspect, a copper alloy is provided, which includes the following elements, measured by mass percentage: Ni 2-3%, Cr 0.1-1.5%, Mn 0.2-1%, 0.05-0.2% of rare earth elements, and the rest are Cu and unavoidable impurities; wherein the rare earth element is La or Ce.

[0008] In some embodiments, the copper alloy includes the following elements, measured in percentage by mass: Ni 2.1-2.6%, Cr 0.5-1%, Mn 0.5-1%, 0.1-0.2% of rare earth elements, and the remainder being Cu and unavoidable impurities; wherein the rare earth element is La or Ce.

[0009] In some embodiments, at a temperature of 350°C, the copper alloy has a tensile strength of ≥450MPa, an elongation of ≥10%, an electrical conductivity of ≥42%IACS, and a hardness of ≥130HV; and under conditions of an ammonia ion concentration of 1 mol / L and a torque of 78 Nm, the copper alloy has a fracture time of ≥36h.

[0010] In a second aspect, a method for preparing the copper alloy is provided, comprising the following steps:

[0011] Corresponding to the element composition of the copper alloy, the prepared raw materials are vacuum melt-casted to obtain an ingot;

[0012] The ingot is subjected to a solid solution treatment to obtain a solid solution ingot;

[0013] The solid solution ingot is hot forged to obtain a hot forged alloy;

[0014] The hot forged alloy is subjected to aging treatment to obtain a copper alloy.

[0015] In some embodiments, the solution treatment is performed at a temperature of 800-950° C. and for a time of 0.5-2 h.

[0016] In some embodiments, the hot forging treatment is performed at a temperature of 700-950° C., with a pass reduction of 15-20% and a total reduction of 45-60%.

[0017] In some embodiments, the aging treatment is performed at a temperature of 400-550° C. and for a time of 0.5-4 h.

[0018] In some embodiments, the smelting temperature is 1150-1300°C.

[0019] A third aspect provides use of the copper alloy in preparing a crystallizer.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The present invention improves the high-temperature comprehensive mechanical properties and stress corrosion resistance of the copper alloy by adding a small amount of Ni and rare earth elements, and is suitable for high-temperature wear-resistant and stress-corrosion-resistant occasions such as continuous casting and rolling casting machine crystallizers.

[0022] (2) The present invention adopts a process route of vacuum melting, solutionizing, hot forging and aging treatment. By selecting specific parameters of solutionizing, hot forging and aging treatment, the previous processes such as ingot casting, cold rolling and the like are reduced. While ensuring the strengthening of the copper alloy, the deformation texture level in the copper alloy is reduced, thereby obtaining a copper alloy with high-temperature comprehensive mechanical properties and stress corrosion resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A product diagram of the copper alloy disclosed in the present invention;

[0024] Figure 2 This is the grain structure diagram of the copper alloy obtained in Example 1. DETAILED DESCRIPTION

[0025] In order to facilitate understanding of the present disclosure, the present disclosure will be described more fully below. However, the present disclosure can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present disclosure more thorough and comprehensive.

[0026] As used herein:

[0027] "Prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0028] The conjunction "consisting of excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed-ended so that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0029] When amount, concentration or other value or parameter is represented by range, preferred range or a series of upper preferred value and lower preferred value, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value and any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when disclosing range "1-5", described range should be interpreted as including range "1-4", "1-3", "1-2", "1-2 and 4-5", "1-3 and 5" etc. When numerical range is described in this article, unless otherwise stated, the range is intended to include its end value and all integers and fractions within the range.

[0030] In these examples, parts and percentages are by mass unless otherwise indicated.

[0031] "Parts by mass" refers to the basic unit of measurement for expressing the mass ratio of multiple components. 1 part can represent any unit mass, such as 1g or 2.689g. If we say that the mass of component A is a parts and the mass of component B is b parts, it means the ratio of the mass of component A to the mass of component B is a:b. Alternatively, it means that the mass of component A is aK and the mass of component B is bK (K is an arbitrary number, indicating a multiple factor). It should not be misunderstood that, unlike the mass parts, the sum of the mass of all components is not limited to 100 parts.

[0032] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0033] In a first aspect, a copper alloy is provided, comprising the following elements, measured in percentage by mass: 2-3% Ni, 0.1-1.5% Cr, 0.2-1% Mn, 0.05-0.2% rare earth elements, and the remainder being Cu and unavoidable impurities; wherein the rare earth element is La or Ce.

[0034] For example, in different embodiments, the Ni content may be, but is not limited to, 2%, 2.1%, 2.2%, 2.3%, 2.4%, 2.5%, 2.6%, 2.7%, 2.8%, 2.9%, 3%; preferably, 2.1-2.6%.

[0035] For example, in different embodiments, the Cr content may be but is not limited to 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.8%, 0.9%, 1.0%, 1.1%, 1.2%, 1.3%, 1.4%, 1.5%; preferably 0.5-1%.

[0036] For example, in different embodiments, the Mn content may be, but is not limited to, 0.2%, 0.3%, 0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, 1%; preferably 0.5-1%.

[0037] As in different embodiments, the content of the rare earth element can be but is not limited to 0.05%, 0.06%, 0.07%, 0.08%, 0.09%, 0.1%, 0.11%, 0.12%, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.2%; preferably 0.1-0.2%.

[0038] The present disclosure improves the mechanical properties and stress corrosion resistance of the copper alloy at high temperatures by adding Ni and Mn. If the addition amount of Ni is less than 2% and / or the addition amount of Mn is less than 0.2%, the mechanical properties of the copper alloy at high temperatures will be reduced; if the addition amount of Ni is greater than 3% and / or the addition amount of Mn is less than 1%, the stress corrosion resistance of the copper alloy will be reduced. The present application preferably adds 2.1-2.6% Ni and / or 0.5-1% Mn to obtain a copper alloy with high mechanical properties and stress corrosion resistance at high temperatures.

[0039] The present disclosure improves the mechanical properties of the copper alloy at high temperatures by adding Cr. If the added amount of Cr is less than 0.1% or greater than 1%, the mechanical properties of the copper alloy at high temperatures will be significantly reduced.

[0040] The rare earth elements disclosed in the present invention play a role in refining the cast structure, improving the solid solution effect of the copper alloy and the dispersion distribution of the precipitated phase in the copper alloy, and improving the mechanical properties and stress corrosion resistance of the copper alloy at high temperatures.

[0041] In some embodiments, the content of unavoidable impurities in the copper alloy is ≤ 0.1% by mass.

[0042] In some embodiments, at a temperature of 350°C, the copper alloy has a tensile strength of ≥450MPa, an elongation of ≥10%, an electrical conductivity of ≥42%IACS, and a hardness of ≥130HV; under the conditions of an ammonia ion concentration of 1 mol / L and a torque of 78 Nm, the fracture time of the copper alloy is ≥36h.

[0043] Specifically, at a temperature of 350°C, the copper alloy has a tensile strength of 450-500 MPa, an elongation of 10-20%, an electrical conductivity of ≥42% IACS, and a hardness of 130-180 HV; under conditions of an ammonia ion concentration of 1 mol / L and a torque of 78 Nm, the fracture time of the copper alloy is ≥36 h. The copper alloy disclosed in the present invention has excellent mechanical properties and stress corrosion resistance at high temperatures.

[0044] In a second aspect, a method for preparing the copper alloy is provided, comprising the following steps:

[0045] Corresponding to the element composition of the copper alloy, vacuum melting and casting the prepared raw materials to obtain an ingot;

[0046] The ingot is subjected to a solid solution treatment to obtain a solid solution ingot;

[0047] The solid solution ingot is hot forged to obtain a hot forged alloy;

[0048] The hot forged alloy is subjected to aging treatment to obtain a copper alloy.

[0049] The present invention discloses a method for preparing copper alloy by using vacuum melting, solutionizing, hot forging and aging treatment, thereby reducing the previous steps of ingot casting, blanking and cold rolling, and reducing the deformation texture level in the copper alloy while ensuring the strengthening of the copper alloy, thereby obtaining a copper alloy with high-temperature comprehensive mechanical properties and stress corrosion resistance.

[0050] In some embodiments, the solution treatment is performed at a temperature of 800-950° C. and for a time of 0.5-2 h.

[0051] For example, in different embodiments, the temperature of the solution treatment may be, but is not limited to, 800°C, 820°C, 840°C, 860°C, 880°C, 900°C, 920°C, 940°C, 950°C, preferably 850-900°C.

[0052] For example, in different embodiments, the solution treatment time may be, but is not limited to, 0.5 h, 0.8 h, 1 h, 1.2 h, 1.5 h, 1.7 h, or 2 h.

[0053] In the present disclosure, the solution treatment can eliminate the internal stress and component segregation in the ingot, making the composition in the copper alloy more uniform. If the temperature of the solution treatment is less than 800°C, the internal stress and component segregation in the ingot cannot be eliminated, and the solution effect cannot be achieved, resulting in a decrease in the mechanical properties and stress corrosion resistance of the copper alloy at high temperatures; if the temperature of the solution treatment is higher than 950°C, it is easy to cause the grain boundaries of the copper alloy to be overburned, causing the copper alloy to crack during the subsequent hot forging process. The preferred solution treatment temperature of the present disclosure is 850-900°C, which improves the effect of the solution treatment, avoids the cracking of the copper alloy during the hot forging process, and obtains a copper alloy with good mechanical properties and stress corrosion resistance at high temperatures.

[0054] In some embodiments, the hot forging treatment is performed at a temperature of 700-950° C., with a pass reduction of 15-20% and a total reduction of 45-60%.

[0055] As in different embodiments, the temperature of the hot forging treatment can be but is not limited to 700°C, 720°C, 750°C, 770°C, 800°C, 830°C, 850°C, 880°C, 900°C, 930°C, 950°C, preferably 800-900°C.

[0056] For example, in different embodiments, the reduction amount of the hot forging process can be, but is not limited to, 15%, 16%, 17%, 18%, 19%, or 20%.

[0057] For example, in different embodiments, the total reduction during hot forging may be, but is not limited to, 45%, 47%, 49%, 51%, 53%, 55%, 58%, or 60%.

[0058] The present invention can significantly improve the internal structure of the copper alloy, further eliminate defects in the ingot, refine the grains in the copper alloy, and improve the mechanical properties and stress corrosion resistance of the copper alloy at high temperatures by controlling the temperature, pass reduction and total reduction of the hot forging process.

[0059] In some embodiments, the aging treatment is performed at a temperature of 400-550° C. and for a time of 0.5-4 h.

[0060] For example, in different embodiments, the temperature of the aging treatment may be, but is not limited to, 400°C, 420°C, 440°C, 460°C, 480°C, or 500°C.

[0061] For example, in different embodiments, the time of aging treatment may be, but is not limited to, 0.5 h, 1 h, 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, or 4 h.

[0062] The present invention forms a precipitated phase through aging treatment, controls the size of the precipitated phase, and obtains a copper alloy with high mechanical properties and stress corrosion resistance at high temperatures. If the temperature of the aging treatment is less than 400°C, the precipitated phase in the copper alloy is difficult to form and the precipitation strengthening effect cannot be achieved. If the temperature of the aging treatment is higher than 550°C, the precipitated phase in the copper alloy grows too fast, resulting in a decrease in the mechanical properties of the copper alloy at high temperatures.

[0063] In some embodiments, the smelting temperature is 1150-1300°C.

[0064] For example, in different embodiments, the smelting temperature may be, but is not limited to, 1150°C, 1170°C, 1200°C, 1230°C, 1250°C, 1280°C, or 1300°C.

[0065] In some embodiments, the vacuum casting step is:

[0066] (1) raw materials of single element Cu, single element Ni, single element Mn, rare earth elements and Cu-Cr master alloy are prepared according to alloy composition;

[0067] (2) adding single element Cu, single element Ni and single element Mn into a graphite crucible of a vacuum casting furnace, evacuating the furnace chamber to a pressure of less than 0.1 Pa, heating the graphite crucible to a temperature of 1150-1300° C., and keeping the temperature for 5-10 minutes. During the heating process, the pressure of the furnace chamber is less than 0.1 Pa;

[0068] (3) After the heat preservation is completed, an inert gas is introduced, and a Cu-Cr master alloy is added, and the heat preservation is carried out for 20-30 minutes; then, a rare earth element is added, and the heat preservation is carried out for 2-5 minutes, and then an ingot is cast.

[0069] For example, in various embodiments, the inert gas may be, but is not limited to, argon.

[0070] A third aspect provides use of the copper alloy in preparing a crystallizer.

[0071] In order to further illustrate the present invention, the corrosion-resistant white copper alloy provided by the present invention is described in detail below in conjunction with the accompanying drawings and embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0072] Example 1

[0073] This embodiment provides a method for preparing a copper alloy, comprising the following steps:

[0074] (1) raw materials of single substance Cu, single substance Ni, single substance Mn, rare earth elements and Cu-Cr master alloy are prepared according to the alloy composition weight percentage of 2.1% Ni, 0.5% Cr, 1% Mn, 0.2% La, and the rest Cu, and the raw materials are washed and dried in a drying oven for 12 hours;

[0075] (2) adding single element Cu, single element Ni and single element Mn into a graphite crucible of a vacuum casting furnace, evacuating the furnace chamber to a pressure of less than 0.1 Pa, heating the graphite crucible to a temperature of 1180° C., and keeping the temperature for 10 min. During the heating process, the pressure of the furnace chamber is less than 0.1 Pa;

[0076] (3) After the heat preservation is completed, an inert gas is introduced, and a Cu-Cr master alloy is added and the heat preservation is carried out for 30 minutes; then, a single element La is added, and the heat preservation is carried out for 5 minutes, and then an ingot is cast;

[0077] (4) subjecting the ingot to a solid solution treatment at a temperature of 850° C., keeping the temperature for 1 hour, and then cooling the ingot to room temperature with water to obtain a solid solution alloy ingot;

[0078] (5) hot forging the solid solution alloy ingot at 800°C for 3 passes, with a reduction of 15% per pass and a total reduction of 45%. After the 3 passes, the ingot was flipped 90°, and the flipping was repeated 2 times, and then water-cooled to room temperature to obtain a hot forged alloy.

[0079] (6) The hot forged alloy was aged at 500°C for 2 h and then air-cooled to room temperature to obtain a copper alloy.

[0080] Example 2

[0081] This embodiment provides a method for preparing a copper alloy, comprising the following steps:

[0082] (1) raw materials of single substance Cu, single substance Ni, single substance Mn, rare earth elements and Cu-Cr master alloy are prepared according to the alloy composition weight percentage of 2.6% Ni, 1% Cr, 0.5% Mn, 0.1% Ce, and the rest Cu, and the raw materials are washed and dried in a drying oven for 12 hours;

[0083] (2) adding single element Cu, single element Ni and single element Mn into a graphite crucible of a vacuum casting furnace, evacuating the furnace chamber to a pressure of less than 0.1 Pa, heating the graphite crucible to a temperature of 1250° C., and keeping the temperature for 5 minutes. During the heating process, the pressure of the furnace chamber is less than 0.1 Pa;

[0084] (3) After the heat preservation is completed, an inert gas is introduced, and a Cu-Cr master alloy is added, and the heat preservation is carried out for 20 minutes; then, single element Ce is added, and the heat preservation is carried out for 5 minutes, and then an ingot is cast;

[0085] (4) subjecting the ingot to a solid solution treatment at a temperature of 900° C., keeping the temperature for 2 h, and then cooling the ingot to room temperature with water to obtain a solid solution alloy ingot;

[0086] (5) hot forging the solid solution alloy ingot at 900°C for 3 passes, with a reduction of 20% per pass and a total reduction of 60%. After the 3 passes, the ingot was flipped 90°, and the flipping was repeated 4 times, and then water-cooled to room temperature to obtain a hot forged alloy;

[0087] (6) The hot forged alloy was aged at 450°C for 3 h and then air-cooled to room temperature to obtain a copper alloy.

[0088] Example 3

[0089] This embodiment provides a method for preparing a copper alloy, comprising the following steps:

[0090] (1) raw materials of single substance Cu, single substance Ni, single substance Mn, rare earth elements and Cu-Cr master alloy are prepared according to the alloy composition weight percentage of 2.6% Ni, 1% Cr, 0.5% Mn, 0.1% Ce, and the rest Cu, and the raw materials are washed and dried in a drying oven for 12 hours;

[0091] (2) adding single element Cu, single element Ni and single element Mn into a graphite crucible of a vacuum casting furnace, evacuating the furnace chamber to a pressure of less than 0.1 Pa, heating the graphite crucible to a temperature of 1250° C., and keeping the temperature for 5 minutes. During the heating process, the pressure of the furnace chamber is less than 0.1 Pa;

[0092] (3) After the heat preservation is completed, an inert gas is introduced, and a Cu-Cr master alloy is added, and the heat preservation is carried out for 20 minutes; then, single element Ce is added, and the heat preservation is carried out for 5 minutes, and then an ingot is cast;

[0093] (4) subjecting the ingot to a solid solution treatment at a temperature of 950° C., keeping the temperature for 2 h, and then cooling the ingot to room temperature with water to obtain a solid solution alloy ingot;

[0094] (5) hot forging the solid solution alloy ingot at 700°C for 3 passes, with a reduction of 20% per pass and a total reduction of 60%. After the 3 passes, the ingot is flipped 90°, and the flipping is repeated 4 times, and then water-cooled to room temperature to obtain a hot forged alloy.

[0095] (6) The hot forged alloy was aged at 400°C for 3 h and then air-cooled to room temperature to obtain a copper alloy.

[0096] Example 4

[0097] This embodiment provides a method for preparing a copper alloy, which differs from Embodiment 2 only in that the composition of the copper alloy components is different. In terms of mass percentage, the composition of the copper alloy in this embodiment is: 2.1% Ni, 0.5% Cr, 0.5% Mn, 0.2% Ce, and the rest is Cu.

[0098] Example 5

[0099] This embodiment provides a method for preparing a copper alloy, which differs from Embodiment 2 only in that the composition of the copper alloy components is different. In terms of mass percentage, the composition of the copper alloy in this embodiment is: 2.1% Ni, 1.5% Cr, 0.2% Mn, 0.2% Ce, and the rest is Cu.

[0100] Example 6

[0101] This embodiment provides a method for preparing a copper alloy, which differs from Embodiment 2 only in that the composition of the copper alloy components is different. In terms of mass percentage, the composition of the copper alloy in this embodiment is: 3% Ni, 0.2% Cr, 0.5% Mn, 0.2% Ce, and the rest is Cu.

[0102] Example 7

[0103] This embodiment provides a method for preparing a copper alloy, which differs from Embodiment 2 only in that the composition of the copper alloy components is different. In terms of mass percentage, the composition of the copper alloy in this embodiment is: 3% Ni, 0.2% Cr, 1% Mn, 0.05% Ce, and the rest is Cu.

[0104] Comparative Example 1

[0105] This comparative example provides a method for preparing a copper alloy, which differs from Example 2 only in that the composition of the copper alloy components is different. In terms of mass percentage, the composition of the copper alloy in this comparative example is: 3.5% Ni, 0.2% Cr, 1% Mn, 0.05% Ce, and the rest is Cu.

[0106] Comparative Example 2

[0107] This comparative example provides a method for preparing a copper alloy, which differs from Example 2 only in that the composition of the copper alloy components is different. In terms of mass percentage, the composition of the copper alloy in this comparative example is: 3% Ni, 0.2% Cr, 1% Mn, 0.25% Ce, and the rest is Cu.

[0108] Comparative Example 3

[0109] This comparative example provides a method for preparing a copper alloy, which differs from Example 2 only in that step (5) is different. Step (5) of this comparative example is: hot forging the solid solution alloy ingot at a temperature of 900°C for 3 times, with a reduction of 25% per pass and a total reduction of 75%. After the 3 deformation passes, the ingot is flipped 90°, and the flipping is repeated 4 times, followed by water cooling to room temperature to obtain a hot forged alloy.

[0110] Comparative Example 4

[0111] This comparative example provides a method for preparing a copper alloy, which differs from Example 2 only in that step (5) is different. Step (5) of this comparative example is: hot forging the solid solution alloy ingot at a temperature of 900°C, with a pass reduction of 8% and a total reduction of 64%. After 3 passes of deformation, the ingot is flipped 90°, and the flipping is repeated 4 times, and then water-cooled to room temperature to obtain a hot forged alloy.

[0112] Comparative Example 5

[0113] This comparative example provides a method for preparing a copper alloy, which differs from Example 2 only in that step (6) is different. Step (6) of this comparative example is: subjecting the hot forged alloy to aging treatment at a temperature of 600°C, keeping the temperature for 3 hours, and then air cooling to room temperature to obtain a copper alloy.

[0114] Comparative Example 6

[0115] This comparative example provides a method for preparing a copper alloy, which differs from Example 2 only in that step (6) is different. Step (6) of this comparative example is: subjecting the hot forged alloy to aging treatment at a temperature of 400°C, keeping the temperature for 3 hours, and then air cooling to room temperature to obtain a copper alloy.

[0116] Performance Testing

[0117] The copper alloys obtained in the examples and comparative examples were tested for performance, and the testing method was as follows:

[0118] (1) Tensile strength: Plate specimen tensile method specified in GB / T 4338-2006.

[0119] (2) Elongation: Plate specimen tensile method specified in GB / T 4338-2006.

[0120] (3) Vickers hardness: GB / T4340.1-1999.

[0121] (4) Conductivity: Directly tested using the PZ60A conductivity tester produced by Lotai Precision Instruments.

[0122] (5) Fracture time: Stress corrosion test conditions are NH 4+ Concentration 6g / L; Cl -The concentration was 0.1 wt%. The solution was kept boiling during the test and the constant strain rate was 10 -7 / s until it breaks.

[0123] The test results are shown in Table 1.

[0124] Table 1

[0125]

[0126]

[0127] From the experimental data in Table 1, it can be seen that at a temperature of 350°C, the copper alloy disclosed in the present invention has a tensile strength of ≥450MPa, an elongation of ≥10%, an electrical conductivity of ≥42%IACS, and a hardness of ≥130HV; under the conditions of an ammonia ion concentration of 1 mol / L and a torque of 78 Nm, the fracture time of the copper alloy is ≥36h.

[0128] Figure 1 This is a product diagram of the copper alloy disclosed in the present invention. Figure 2 The grain structure diagram of the copper alloy obtained in Example 1 is shown in FIG. Figure 2 The average grain size is 57 μm. After aging, a large number of twins are produced, but there is no abnormally grown transgranular second phase.

[0129] Finally, it should be noted that the above embodiments are used to illustrate the technical solution of the present disclosure rather than to limit the protection scope of the present disclosure. Although the present disclosure has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present disclosure can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present disclosure.

Claims

1. A copper alloy, characterized in that: The following elements are included in terms of mass percentage: Ni 2-3%, Cr 0.1-1.5%, Mn 0.2-1%, 0.05-0.2% of rare earth elements, and the remainder is Cu and unavoidable impurities; wherein the rare earth element is La or Ce.

2. The copper alloy according to claim 1, characterized in that The following elements are included in terms of mass percentage: Ni 2.1-2.6%, Cr 0.5-1%, Mn 0.5-1%, 0.1-0.2% of rare earth elements, and the remainder is Cu and unavoidable impurities; wherein the rare earth element is La or Ce.

3. The copper alloy according to claim 1 or 2, characterized in that At a temperature of 350° C., the copper alloy has a tensile strength of ≥450 MPa, an elongation of ≥10%, an electrical conductivity of ≥42% IACS, and a hardness of ≥130 HV; and under conditions of an ammonia ion concentration of 1 mol / L and a torque of 78 Nm, the breaking time of the copper alloy is ≥36 h.

4. A method for preparing a copper alloy according to any one of claims 1 to 3, characterized in that: The following steps are involved: Corresponding to the element composition of the copper alloy, the prepared raw materials are vacuum melt-casted to obtain an ingot; The ingot is subjected to a solid solution treatment to obtain a solid solution ingot; The solid solution ingot is hot forged to obtain a hot forged alloy; The hot forged alloy is subjected to aging treatment to obtain a copper alloy.

5. The method for preparing the copper alloy according to claim 4, characterized in that: The temperature of the solution treatment is 800-950° C. and the time is 0.5-2 h.

6. The method for preparing the copper alloy according to claim 4, characterized in that: The temperature of the hot forging treatment is 700-950° C., the reduction per pass is 15-20%, and the total reduction is 45-60%.

7. The method for preparing a copper alloy according to claim 4, characterized in that: The aging treatment is carried out at a temperature of 400-550° C. and for a time of 0.5-4 h.

8. The method for preparing a copper alloy according to claim 4, characterized in that: The temperature of the vacuum casting is 1150-1300°C.

9. Use of the copper alloy according to any one of claims 1 to 3 in preparing a crystallizer.

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