A high-performance copper-chromium alloy and its preparation method

Abstract

The present invention provides a high-performance copper-chromium alloy and a preparation method thereof, belonging to the technical field of copper alloy manufacturing. The high-performance copper-chromium alloy provided by the present invention, by mass percentage, comprises the following chemical components: Cr: 0.1-0.8%, Sn: 0.01-0.2%, Ti: 0.01-0.1%, micro-alloying elements 0.02-0.5%, rare earth elements ≤0.08% and the balance of Cu; the molar ratio of Sn to Ti is (1-1.5):1. The results of the examples show that the high-performance copper-chromium alloy provided by the present invention has a tensile strength ≥625 MPa, a hardness of 170-200 HV, a conductivity ≥77%, the hardness is not lower than 80% of the original hardness after being kept at 500 °C and 530 °C for 1 h respectively, and the stress remains above 80% after being treated at 200 °C for 1000 h.

Description

Technical Field

[0001] The invention relates to the technical field of copper alloy manufacturing, and in particular to a high-performance copper-chromium alloy and a preparation method thereof. Background Art

[0002] Copper alloy has good comprehensive properties such as mechanical, thermal and electrical conductivity, and is one of the most widely used nonferrous metal materials. In recent years, with the rapid development of electrical and electronic, aerospace, transportation, marine engineering and other fields, the core components have higher and higher requirements on the comprehensive performance, service life, production efficiency, green manufacturing and other aspects of copper alloys. Copper-chromium alloy is one of the typical representatives of high-performance copper alloys. Because of its excellent electrical conductivity, thermal conductivity, mechanical properties and high temperature performance, copper-chromium alloy has a wide range of market demand in the fields of wire and cable inner conductors, high-speed train contact wires, large-scale integrated circuit lead frame materials, electrode materials, etc., and the market demand is growing rapidly.

[0003] With the development of science and technology, the copper-chromium alloys currently sold on the market can no longer meet the technical requirements. Therefore, providing a high-performance copper-chromium alloy with excellent mechanical properties and conductive properties has become a technical problem that needs to be urgently solved in this field. Summary of the invention

[0004] The purpose of the present invention is to provide a high-performance copper-chromium alloy and a preparation method thereof. The high-performance copper-chromium alloy provided by the present invention has excellent mechanical properties and electrical conductivity, and also has excellent stress relaxation resistance and high-temperature oxidation resistance.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] The present invention provides a high-performance copper-chromium alloy, which comprises the following chemical components by mass percentage: Cr: 0.1-0.8%, Sn: 0.01-0.2%, Ti: 0.01-0.1%, micro-alloy elements 0.02-0.5%, rare earth elements ≤0.08% and the balance of Cu;

[0007] The molar ratio of Sn to Ti is (1-1.5):1;

[0008] The microalloying element comprises at least one of Si, Zr, Mg and Ag;

[0009] The rare earth element includes Ce and / or Y.

[0010] Preferably, the microalloying elements include, by mass percentage, at least one of: Si: 0.01-0.1%, Zr: 0.05-0.15%, Mg: 0.005-0.05% and Ag: 0.01-0.2%.

[0011] Preferably, by mass percentage, it includes the following chemical components: Cr: 0.2 - 0.5%, Sn: 0.05 - 0.18%, Ti: 0.02 - 0.08%, micro alloying elements 0.04 - 0.4%, rare earth elements: 0.04 - 0.08% and the balance of Cu.

[0012] The present invention provides a method for preparing the high-performance copper-chromium alloy described in the above technical solution, including the following steps:

[0013] (1) Melting and semi-continuously casting the alloy raw materials in sequence to obtain a billet;

[0014] (2) Subjecting the billet obtained in the step (1) to homogenization heat treatment and hot rolling in sequence to obtain a hot-rolled plate and strip;

[0015] (3) Rough rolling the hot-rolled plate and strip obtained in the step (2) to obtain a rough-rolled plate and strip;

[0016] (4) Subjecting the rough-rolled plate and strip obtained in the step (3) to aging treatment and medium rolling in sequence to obtain a medium-rolled plate and strip;

[0017] (5) Subjecting the medium-rolled plate and strip obtained in the step (4) to stress relief annealing and finish rolling in sequence to obtain a high-performance copper-chromium alloy.

[0018] Preferably, in the step (2), the initial rolling temperature of the hot rolling is 700 - 950 °C, the final rolling temperature of the hot rolling is 550 °C - 650 °C, and the total deformation amount of the hot rolling is 70 - 95%.

[0019] Preferably, in the step (3), the temperature of the rough rolling is normal temperature, and the total deformation amount of the rough rolling is 70 - 95%.

[0020] Preferably, in the step (4), the temperature of the aging treatment is 400 - 500 °C, and the heat preservation time of the aging treatment is 4 - 10 h.

[0021] Preferably, in the step (4), the medium rolling temperature is normal temperature, and the total deformation amount of the medium rolling is 50 - 80%.

[0022] Preferably, in the step (5), the temperature of the stress relief annealing is 300 - 450 °C, and the heat preservation time of the stress relief annealing is 4 - 10 h.

[0023] Preferably, in the step (5), the temperature of the finish rolling is normal temperature, and the total deformation amount of the finish rolling is 50 - 80%.

[0024] The present invention provides a high-performance copper-chromium alloy, which, by mass percentage, comprises the following chemical components: Cr: 0.1-0.8%, Sn: 0.01-0.2%, Ti: 0.01-0.1%, micro-alloying elements 0.02-0.5%, rare-earth elements ≤0.08% and the balance of Cu; the molar ratio of Sn to Ti is (1-1.5):1; the micro-alloying elements include at least one of Si, Zr, Mg and Ag; the rare-earth elements include Ce and / or Y. By adding Cr element, the present invention can form Cr primary phase in the copper alloy, thereby improving the mechanical properties of the copper alloy; tin element can promote the formation of Cr-rich primary phase, and some Cr-rich primary phases will be drawn into fibrous shape during thermomechanical treatment, thus achieving a strengthening effect; titanium element and tin element form TiSn phase in the copper matrix, which can further improve the strength, hardness and heat resistance; adding a certain amount of silicon element can refine the grains and further improve the strength of the alloy; complex ternary compounds will be formed between copper, chromium and zirconium, which is beneficial to refining the grains and further improving the mechanical properties of the copper alloy; magnesium element can promote the complete precipitation of the precipitated phase. At the same time, the magnesium atoms dissolved in the alloy matrix will drag the dislocations, improving the stress relaxation resistance of the alloy and further improving the processing accuracy of the alloy; adding an appropriate amount of silver element can increase the softening temperature of the alloy and has little effect on the conductivity; through the compounding of various micro-alloying elements and strict control of their contents, the mechanical properties and conductivity of the copper-chromium alloy are further improved; by introducing a certain amount of rare-earth elements into the copper alloy, metal intermetallic compounds with high hardness and uniform distribution can be formed with copper element, and these compounds become the resistance to dislocation movement; moreover, rare-earth elements can effectively improve the existing form and distribution of inclusions, reduce the possibility of weakening the grain boundaries, and reduce the probability of cracking along the grain boundaries when bearing loads, thus improving the wear resistance; at the same time, rare-earth elements can improve the processing performance of the copper alloy, and further improve the mechanical properties and conductivity of the copper-chromium alloy. The results of the examples show that the high-performance copper-chromium alloy provided by the present invention has a tensile strength ≥625 MPa, a hardness of 170-200 HV, a conductivity ≥77%, the hardness is not lower than 80% of the original hardness after heat preservation at 500 °C and 530 °C for 1 h respectively, and the stress remains above 80% after treatment at 200 °C for 1000 h, indicating that the high-performance copper-chromium alloy provided by the present invention has excellent stress relaxation resistance and high-temperature oxidation resistance. Detailed Embodiments

[0025] The present invention provides a high-performance copper-chromium alloy, which, by mass percentage, comprises the following chemical components: Cr: 0.1-0.8%, Sn: 0.01-0.2%, Ti: 0.01-0.1%, micro-alloying elements 0.02-0.5%, rare-earth elements ≤0.08% and the balance of Cu;

[0026] The molar ratio of Sn to Ti is (1 to 1.5):1;

[0027] The microalloying element includes at least one of Si, Zr, Mg, and Ag;

[0028] The rare earth element includes Ce and / or Y.

[0029] By mass percentage, the high-performance copper-chromium alloy provided by the present invention includes Cr: 0.1 to 0.8%, preferably 0.2 to 0.5%, and more preferably 0.4 to 0.5%. By adding the Cr element, the present invention can form a primary Cr phase in the copper alloy, thereby improving the mechanical properties of the copper alloy.

[0030] By mass percentage, the high-performance copper-chromium alloy provided by the present invention includes Sn: 0.01 to 0.2%, preferably 0.05 to 0.18%, and more preferably 0.1 to 0.15%. In the present invention, the tin element promotes the formation of the primary Cr-rich phase. Some of the primary Cr-rich phases will be drawn into fibrous shapes during the thermomechanical treatment, thereby achieving a strengthening effect. By controlling the content of the tin element within the above range, it is possible to prevent the excessive content of the tin element from affecting the conductivity of the alloy.

[0031] By mass percentage, the high-performance copper-chromium alloy provided by the present invention includes Ti: 0.01 to 0.1%, preferably 0.02 to 0.08%, and more preferably 0.05 to 0.06%. In the present invention, the titanium element and the tin element form a TiSn phase in the copper matrix, which can further improve the strength, hardness, and heat resistance. However, the titanium element inhibits the growth of the primary Cr phase, and its content needs to be strictly controlled to avoid the excessive content of the titanium element from affecting the conductivity of the alloy.

[0032] In the present invention, the molar ratio of Sn to Ti is (1 to 1.5):1, preferably (1.1 to 1.2):1. By controlling the dosage relationship between Sn and Ti, the present invention can further improve the mechanical properties of the alloy.

[0033] By mass percentage, the high-performance copper-chromium alloy provided by the present invention includes 0.02-0.5% of microalloying elements, preferably 0.04-0.4%, more preferably 0.045-0.35%. In the present invention, based on the mass percentage of the high-performance copper-chromium alloy being 100%, the microalloying elements include at least one of Si, Zr, Mg, and Ag, preferably at least one of: Si: 0.01-0.1%, Zr: 0.05-0.15%, Mg: 0.005-0.05%, and Ag: 0.01-0.2%. Adding a certain amount of silicon element in the present invention can refine the grains and further improve the strength of the alloy; complex ternary compounds will be formed between copper, chromium, and zirconium, which is beneficial to refining the grains and further improving the mechanical properties of the copper alloy; magnesium element can promote the complete precipitation of the precipitated phase. At the same time, the magnesium atoms dissolved in the alloy matrix will play a dragging role on dislocations, improving the stress relaxation resistance of the alloy, and then improving the processing accuracy of the alloy; adding an appropriate amount of silver element can increase the softening temperature of the alloy and has little effect on the conductivity. By compounding a variety of microalloying elements and strictly controlling their contents, the present invention further improves the mechanical properties and electrical conductivity of the copper-chromium alloy.

[0034] By mass percentage, the high-performance copper-chromium alloy provided by the present invention includes rare earth elements ≤0.08%, preferably 0.04-0.08%, more preferably 0.04-0.06%. In the present invention, the rare earth elements include Ce and / or Y, more preferably Ce and Y. In the present invention, when the rare earth elements are Ce and Y, the contents of Ce and Y are independently preferably ≤0.04%, more preferably 0.02-0.04%, and further preferably 0.02-0.03%. By introducing a certain amount of rare earth elements into the copper alloy, the present invention can form intermetallic compounds with high hardness and uniform distribution with copper elements, and these compounds become the resistance to dislocation movement; moreover, rare earth elements can effectively improve the existence form and distribution of inclusions, reduce the possibility of weakening the grain boundaries, and reduce the probability of cracking along the grain boundaries when bearing loads, thus improving the wear resistance; at the same time, rare earth elements can improve the processing performance of the copper alloy, and then improve the mechanical properties and electrical conductivity of the copper-chromium alloy.

[0035] By mass percentage, the high-performance copper-chromium alloy provided by the present invention includes the balance of Cu. In the present invention, copper is the matrix element of the alloy.

[0036] The present invention can form Cr primary phases in the copper alloy by adding Cr elements, thereby improving the mechanical properties of the copper alloy; tin elements can promote the formation of Cr-rich primary phases, and some of the Cr-rich primary phases will be drawn into fibrous shapes during thermomechanical treatment, thus achieving a strengthening effect; titanium elements and tin elements form TiSn phases in the copper matrix, which can further improve the strength, hardness and heat resistance; adding a certain amount of silicon elements can refine the grains and further improve the strength of the alloy; complex ternary compounds will be formed between copper, chromium and zirconium, which is beneficial to refining the grains and further improving the mechanical properties of the copper alloy; magnesium elements can promote the complete precipitation of the precipitated phases. At the same time, the magnesium atoms dissolved in the alloy matrix will drag the dislocations, improving the stress relaxation resistance of the alloy and further improving the processing accuracy of the alloy; adding an appropriate amount of silver elements can increase the softening temperature of the alloy and have little effect on the electrical conductivity; through the compounding of various micro-alloying elements and strict control of their contents, the mechanical properties and electrical conductivity of the copper-chromium alloy are further improved; by introducing a certain amount of rare earth elements into the copper alloy, metal compounds with high hardness and uniform distribution can be formed with copper elements, and these compounds become the resistance to dislocation movement; moreover, rare earth elements can effectively improve the existence form and distribution of inclusions, reduce the possibility of weakening the grain boundaries, and reduce the probability of cracking along the grain boundaries when bearing loads, thus improving the wear resistance; at the same time, rare earth elements can improve the processing performance of the copper alloy, and further improve the mechanical properties and electrical conductivity of the copper-chromium alloy.

[0037] The present invention also provides a preparation method of the high-performance copper-chromium alloy described in the above technical solution, including the following steps:

[0038] (1) Melting and semi-continuously casting the alloy raw materials in sequence to obtain a billet;

[0039] (2) Subjecting the billet obtained in step (1) to homogenization heat treatment and hot rolling in sequence to obtain a hot-rolled plate and strip;

[0040] (3) Performing primary rolling on the hot-rolled plate and strip obtained in step (2) to obtain a primary-rolled plate and strip;

[0041] (4) Subjecting the primary-rolled plate and strip obtained in step (3) to aging treatment and medium rolling in sequence to obtain a medium-rolled plate and strip;

[0042] (5) Subjecting the medium-rolled plate and strip obtained in step (4) to stress relief annealing and finish rolling in sequence to obtain the high-performance copper-chromium alloy.

[0043] The present invention melts and semi-continuously casts the alloy raw materials in sequence to obtain a billet.

[0044] The present invention does not have special limitations on the specific types of the alloy raw materials, and commercially available products or recycled waste known to those skilled in the art can be used. In the present invention, the recycled waste preferably includes milling waste and rolling waste generated during the preparation of high-performance copper-chromium alloy; the amount of the recycled waste is preferably 50 wt% or more of the total amount of the alloy raw materials. By using recycled waste as the alloy raw materials, since the recycled waste is milling waste and rolling waste generated during the preparation of high-performance copper-chromium alloy and its composition is controllable, it can not only ensure that the chemical composition of the high-performance copper-chromium alloy meets the requirements, but also realize the reuse of waste and save a large amount of production costs.

[0045] In the present invention, the melting is preferably carried out in a vacuum furnace. The present invention does not have special limitations on the specific model of the vacuum furnace, and commercially available products known to those skilled in the art can be used. In the present invention, the melting temperature is preferably 1300-1350 °C; the holding time of the melting is preferably 30-120 min. The present invention does not have special limitations on the vacuum degree during the melting, and it can be determined according to the common technical knowledge of those skilled in the art. By carrying out the melting in a vacuum furnace, the present invention can avoid the reaction of the metal with oxygen in the air, thereby reducing the content of oxygen impurities.

[0046] In the present invention, the temperature of the semi-continuous casting is preferably 1155-1250 °C; the drawing rate of the semi-continuous casting is preferably 30-60 mm / min, more preferably 40-50 mm / min.

[0047] After obtaining the billet, the present invention sequentially performs homogenization heat treatment and hot rolling on the billet to obtain hot-rolled strip.

[0048] In the present invention, the temperature of the homogenization heat treatment is preferably 900-970 °C; the holding time of the homogenization heat treatment is preferably 5-10 h, more preferably 6-8 h; the homogenization heat treatment is preferably carried out in a walking beam furnace. By the homogenization heat treatment, the present invention can reduce the element segregation inside the billet, thereby laying a foundation for the subsequent rolling.

[0049] In the present invention, the initial rolling temperature of the hot rolling is preferably 700 to 950 °C, more preferably 750 to 900 °C, and further preferably 800 to 900 °C; the final rolling temperature of the hot rolling is preferably 550 °C to 650 °C, more preferably 570 °C to 620 °C, and further preferably 600 °C; the total deformation amount of the hot rolling is preferably 70 to 95%, more preferably 75 to 90%, and further preferably 80 to 85%; the single-pass deformation amount of the hot rolling is preferably 5 to 40%, more preferably 10 to 35%. Through hot rolling, the present invention can improve the processing performance of the alloy, break the coarse grains in the as-cast state, significantly heal cracks, reduce or eliminate casting defects, transform the as-cast structure into a deformed structure, and improve the processing performance of the alloy.

[0050] After the hot rolling is completed, the present invention preferably quenches and faces the product of the hot rolling in sequence. The present invention has no special limitation on the specific operation of the quenching, and it can be determined according to the common technical knowledge of those skilled in the art. In the present invention, the upper and lower facing amounts of the facing are preferably independently 0.8 to 1.2 mm, and more preferably 1 mm. Through the facing treatment, the present invention can remove the oxide layer, thereby avoiding the negative impact of oxygen elements on the performance of the copper alloy.

[0051] After obtaining the hot-rolled strip, the present invention subjects the hot-rolled strip to initial rolling to obtain an initially rolled strip.

[0052] In the present invention, the temperature of the initial rolling is preferably room temperature; the total deformation amount of the initial rolling is preferably 70 to 95%, more preferably 80 to 90%; the single-pass deformation amount of the initial rolling is preferably 15 to 30%, more preferably 20 to 25%. Through initial rolling, the present invention can greatly reduce the thickness of the copper alloy billet, so as to facilitate the preparation of a copper-chromium alloy with a thickness meeting the requirements.

[0053] After the initial rolling is completed, the present invention preferably subjects the product of the initial rolling to trimming. In the present invention, the trimming width of the trimming treatment is preferably 5 mm. In the present invention, the role of trimming is to cut off the cracked edge to ensure the smooth progress of the subsequent processes.

[0054] After obtaining the initially rolled strip, the present invention subjects the initially rolled strip to aging treatment and intermediate rolling in sequence to obtain an intermediate-rolled strip.

[0055] In the present invention, the temperature of the aging treatment is preferably 400 to 500 °C, more preferably 450 to 480 °C; the holding time of the aging treatment is preferably 4 to 10 h, more preferably 6 to 8 h; the cooling method of the aging treatment is preferably natural cooling. In the present invention, the role of the aging treatment is to precipitate other elements dissolved in the copper matrix, strengthen the mechanical properties of the copper alloy through the precipitated phase, and at the same time improve the purity of the copper matrix, thereby improving the conductivity of the alloy.

[0056] In the present invention, the medium rolling temperature is preferably room temperature; the total deformation amount of the medium rolling is preferably 50-80%, more preferably 60-70%; the single-pass deformation amount of the medium rolling is preferably 15-25%, more preferably 20%. Through medium rolling, the present invention can further reduce the thickness of the copper alloy strip.

[0057] After obtaining the medium-rolled strip, the present invention sequentially performs stress relief annealing and finish rolling on the medium-rolled strip to obtain a high-performance copper-chromium alloy.

[0058] In the present invention, the temperature of the stress relief annealing is preferably 300-450 °C, more preferably 350-400 °C; the heat preservation time of the stress relief annealing is preferably 4-10 h, more preferably 6-8 h. Through stress relief annealing, the present invention can not only soften the copper alloy for subsequent rolling, but also make the grain size more uniform and remove the residual internal stress at the same time.

[0059] In the present invention, the temperature of the finish rolling is preferably room temperature; the total deformation amount of the finish rolling is preferably 50-80%, more preferably 60-70%; the single-pass deformation amount of the finish rolling is preferably 10-25%, more preferably 15-20%. Through finish rolling, the present invention can make the thickness of the copper alloy strip meet the technical requirements.

[0060] The preparation method provided by the present invention is simple. By optimizing the heat treatment and rolling treatment processes of the high-performance copper-chromium alloy, the internal stress of the copper alloy is eliminated. By adding aging treatment, the solubility of chromium in copper can be increased, thereby improving the mechanical properties and conductivity. No new equipment needs to be added, and the production cost is low, which is suitable for large-scale industrial promotion.

[0061] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments in the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0062] Example 1

[0063] A high-performance copper-chromium alloy, by mass percentage, consists of the following chemical components: Cr: 0.5%, Sn: 0.065%, Ti: 0.024%, Si: 0.1%, Ce: 0.04%, Y: 0.04% and the balance of Cu;

[0064] The preparation method of the high-performance copper-chromium alloy is specifically the following steps:

[0065] (1) The alloy raw materials are melted in a vacuum furnace and then semi - continuously cast to obtain a billet. The melting temperature is 1300 °C and the melting holding time is 60 min. The semi - continuous casting temperature is 1200 °C and the drawing rate of semi - continuous casting is 50 mm / min.

[0066] (2) The billet obtained in step (1) is subjected to homogenization heat treatment in a walking beam furnace, then hot - rolled, and finally water - quenched and face - milled in sequence to obtain a hot - rolled sheet and strip. The homogenization heat treatment temperature is 940 °C and the homogenization heat treatment holding time is 8 h. The initial rolling temperature of the hot - rolling is 940 °C, the final rolling temperature is 600 °C, the total deformation of the hot - rolling is 90%, and the single - pass deformation of the hot - rolling is 15%. The amount of upper and lower face - milling in the face - milling is independently 1 mm.

[0067] (3) The hot - rolled sheet and strip obtained in step (2) is subjected to rough rolling and then edge - trimming treatment to obtain a rough - rolled sheet and strip. The rough - rolling temperature is room temperature. The total deformation of the rough - rolling is 80% and the single - pass deformation of the rough - rolling is 20%. The edge - trimming width in the edge - trimming treatment is 5 mm.

[0068] (4) The rough - rolled sheet and strip obtained in step (3) is subjected to aging treatment and medium rolling in sequence to obtain a medium - rolled sheet and strip. The aging treatment temperature is 450 °C. The aging treatment holding time is 8 h. The cooling method of the aging treatment is natural cooling. The medium - rolling temperature is room temperature. The total deformation of the medium - rolling is 60%. The single - pass deformation of the medium - rolling is 15%.

[0069] (5) The medium - rolled sheet and strip obtained in step (4) is subjected to stress - relieving annealing and finish rolling in sequence to obtain a high - performance copper - chromium alloy. The stress - relieving annealing temperature is 400 °C and the stress - relieving annealing holding time is 6 h. The finish - rolling temperature is room temperature, the total deformation of the finish - rolling is 60%, and the single - pass deformation of the finish - rolling is 15%.

[0070] Example 2

[0071] A high - performance copper - chromium alloy, by mass percentage, consists of the following chemical components: Cr: 0.4%, Sn: 0.065%, Ti: 0.024%, Zr: 0.15%, Mg: 0.025%, Ce: 0.04%, Y: 0.03% and the balance of Cu.

[0072] The preparation method is the same as that of Example 1.

[0073] Example 3

[0074] A high-performance copper-chromium alloy, by mass percentage, consists of the following chemical components: Cr: 0.6%, Sn: 0.065%, Ti: 0.024%, Ag: 0.12%, Ce: 0.04%, Y: 0.04% and the balance of Cu;

[0075] The preparation method is the same as that of Example 1.

[0076] Example 4

[0077] A high-performance copper-chromium alloy, by mass percentage, consists of the following chemical components: Cr: 0.4%, Sn: 0.065%, Ti: 0.024%, Zr: 0.1%, Mg: 0.040%, Ce: 0.02%, Y: 0.04% and the balance of Cu;

[0078] The preparation method is the same as that of Example 1.

[0079] Example 5

[0080] A high-performance copper-chromium alloy, by mass percentage, consists of the following chemical components: Cr: 0.7%, Sn: 0.059%, Ti: 0.024%, Si: 0.14%, Ce: 0.03%, Y: 0.03% and the balance of Cu;

[0081] The preparation method is the same as that of Example 1.

[0082] The properties of the high-performance copper-chromium alloys prepared in Examples 1 to 5 were tested, and the results are shown in Table 1:

[0083] Table 1 Properties of the high-performance copper-chromium alloys prepared in Examples 1 to 5

[0084]

[0085]

[0086] Among them, the test method for tensile strength is: GB / T 34505-2017 Room temperature tensile test method;

[0087] The specific test method for hardness is: GB / T4340.1-2009 Metallic materials - Vickers hardness test method;

[0088] The test method for conductivity is: YS / T 478-2005 Conductivity eddy current testing method;

[0089] The test method for stress relaxation resistance is: GB / T10120-1996 Metallic materials - Tensile stress relaxation test method; After testing, the stress of the performance copper-chromium alloy provided by the present invention remains above 80% after being treated at 200 °C for 1000 h;

[0090] The test method for high-temperature oxidation resistance is: GB / T 33370-2016 Determination Method for Softening Temperature of Copper and Copper Alloys; after testing, the hardness of the high-performance copper-chromium alloy provided by the present invention is not less than 80% of the original hardness when kept at 500 °C and 530 °C for 1 h respectively.

[0091] As can be seen from Table 1, the high-performance copper-chromium alloy provided by the present invention has a tensile strength ≥ 625 MPa, a hardness of 170-200 HV, a conductivity ≥ 77%, and the hardness is not less than 80% of the original hardness when kept at 500 °C and 530 °C for 1 h respectively, and the stress remains above 80% after being treated at 200 °C for 1000 h, indicating that the high-performance copper-chromium alloy provided by the present invention has excellent stress relaxation resistance and high-temperature oxidation resistance.

[0092] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A high performance copper-chromium alloy, composed by mass percentage of the following chemical components: Cr: 0.1~0.8%, Sn: 0.01~0.2%, Ti: 0.01~0.1%, micro alloying elements 0.02~0.5%, rare earth elements ≤0.08% and the balance Cu; The molar ratio of Sn to Ti is (1-1.5):1; The microalloying element comprises at least one of Si, Zr, Mg and Ag; The rare earth elements include Ce and / or Y; The preparation method of the high-performance copper-chromium alloy comprises the following steps: (1) melting and semi-continuously casting the alloy raw materials in sequence to obtain a casting billet; (2) subjecting the ingot obtained in step (1) to homogenization heat treatment and hot rolling in sequence to obtain hot-rolled strip; in step (2), the initial rolling temperature of hot rolling is 700-950° C., the final rolling temperature of hot rolling is 550-650° C., and the total deformation of hot rolling is 70-95%; (3) performing initial rolling on the hot-rolled strip obtained in step (2) to obtain an initial rolled strip; (4) subjecting the initially rolled strip obtained in step (3) to aging treatment and intermediate rolling in sequence to obtain an intermediate rolled strip; the aging treatment temperature in step (4) is 400 to 500° C., and the aging treatment holding time is 4 to 10 h; (5) The medium-rolled plate and strip obtained in step (4) are subjected to stress relief annealing and finish rolling in sequence to obtain a high-performance copper-chromium alloy.

2. The high performance copper-chromium alloy according to claim 1, characterized in that: In terms of mass percentage, the microalloying elements The present invention comprises at least one of Si: 0.01-0.1%, Zr: 0.05-0.15%, Mg: 0.005-0.05% and Ag: 0.01-0.2%.

3. The high performance copper-chromium alloy according to claim 1, characterized in that: Calculated by mass percentage, it is composed of the following chemical components: Cr: 0.2-0.5%, Sn: 0.05-0.18%, Ti: 0.02-0.08%, micro-alloy elements 0.04-0.4%, rare earth elements: 0.04-0.08% and the balance Cu.

4. The method for preparing the high performance copper-chromium alloy according to any one of claims 1 to 3 comprises the following steps: (1) melting and semi-continuously casting the alloy raw materials in sequence to obtain a casting billet; (2) subjecting the ingot obtained in step (1) to homogenization heat treatment and hot rolling in sequence to obtain hot-rolled strip; in step (2), the initial rolling temperature of hot rolling is 700-950° C., the final rolling temperature of hot rolling is 550-650° C., and the total deformation of hot rolling is 70-95%; (3) performing initial rolling on the hot-rolled strip obtained in step (2) to obtain an initial rolled strip; (4) subjecting the initially rolled strip obtained in step (3) to aging treatment and intermediate rolling in sequence to obtain an intermediate rolled strip; the aging treatment temperature in step (4) is 400 to 500° C., and the aging treatment holding time is 4 to 10 h; (5) The medium-rolled plate and strip obtained in step (4) are subjected to stress relief annealing and finish rolling in sequence to obtain a high-performance copper-chromium alloy.

5. The preparation method according to claim 4, characterized in that: The temperature of the initial rolling in the step (3) is room temperature, and the total deformation of the initial rolling is 70-95%.

6. The preparation method according to claim 4, characterized in that: The intermediate rolling temperature in step (4) is room temperature, and the total deformation amount of the intermediate rolling is 50-80%.

7. The preparation method according to claim 4, characterized in that: The temperature of the stress relief annealing in the step (5) is 300 to 450° C., and the holding time of the stress relief annealing is 4 to 10 hours.

8. The preparation method according to claim 4, characterized in that: The temperature of the finishing rolling in the step (5) is room temperature, and the total deformation of the finishing rolling is 50-80%.

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