Preparation method and application of copper-zirconium alloy ring piece

Abstract

The application discloses a preparation method and application of a copper-zirconium alloy ring piece, and the preparation method of the copper-zirconium alloy ring piece comprises the following steps: S1, melting; S2, casting; S3, hot forging and solid solution treatment; S4, primary cold forging and primary heat treatment; and S5, secondary cold forging and secondary heat treatment. The copper-zirconium alloy ring piece prepared by the application can be applied to a squirrel-cage asynchronous motor end ring product. Through the combination of trace Zn addition and a specific preparation process, the preparation method can obtain a relatively pure CuZr alloy material, the tensile strength and the electrical conductivity of the CuZr alloy can reach above 400 MPa and 90% IACS respectively, the strength and the electrical conductivity of the CuZr alloy are well matched, and the CuZr alloy can be applied to the squirrel-cage asynchronous motor end ring product.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of copper alloys, in particular to a preparation method and application of a copper-zirconium alloy ring piece. BACKGROUND

[0002] An end ring is an important component of a rotor winding of a squirrel cage asynchronous motor, and is required to have good electrical conductivity and thermal conductivity, high strength and high-temperature softening resistance. Currently, the material used for the end ring of the squirrel cage asynchronous motor is mainly copper metal and its alloy, such as Cu-HCP, CuCr, CuCrZr, CuNi2Si and the like. However, with the development of rail transportation, higher requirements are put forward for high-power motors. Since the end ring is mainly connected with a bar by brazing during motor assembly, and the outer side is reinforced by a retainer, the strength of the end ring needs to meet the requirements of the working environment from the reliability aspect. However, from the use aspect, the end ring with excellent electrical conductivity can greatly improve the efficiency of the motor, and therefore, it is important to select a suitable material and preparation process to obtain a good match between the electrical conductivity and the strength.

[0003] The CuZr alloy itself has high electrical conductivity and softening resistance, and the strength can be further improved through suitable process optimization. Therefore, the application designs a preparation method of a copper-zirconium alloy ring piece to further improve the strength of the CuZr alloy. SUMMARY

[0004] To solve the above technical problems, the application provides a preparation method and application of a copper-zirconium alloy ring piece.

[0005] The technical scheme of the application is as follows: a preparation method of a copper-zirconium alloy ring piece, characterized by comprising the following steps:

[0006] S1, melting:

[0007] The raw materials include the following components in terms of mass ratio: 0.13-0.18 wt.% of Zr, 0.02 wt.% or less of Zn, and the balance of Cu;

[0008] The above raw materials are placed in a vacuum medium-frequency induction furnace for melting, the melting temperature is 1300-1400 DEG C, the melting time is 30-40 min, and the melting process is kept deoxygenated to obtain an alloy melt;

[0009] S2, casting:

[0010] The alloy solution is cast by using a bottom casting system, the casting temperature is 1250-1300 DEG C, a copper-zirconium alloy ingot is obtained, and the ingot is subjected to turning processing to remove surface defects;

[0011] S3, hot forging and solid solution treatment:

[0012] According to the finished product weight of the copper-zirconium alloy ring, the copper-zirconium alloy ingot is sawn and cut, the sawn ingot is heated to 900-950℃, the heating time is 30-60min, and the temperature is kept for 30-60min; then the forging clamp is preheated to 250-350℃, and then the upsetting-punching-boring process is performed using a 1T air hammer. During the hot forging process, the initial forging temperature is 850-900℃, and the final forging temperature is 640-660℃. The hot forging process ends to obtain a hot-forged ingot that meets the requirements;

[0013] The hot-forged ingot is heated to 900-960℃ at a heating rate of 19-25℃ / min, and kept for 60-90min. After the temperature keeping is completed, the blank is discharged and water-cooled to room temperature to obtain a supersaturated copper-zirconium alloy blank;

[0014] S4, primary cold forging and heat treatment:

[0015] The supersaturated copper-zirconium alloy blank obtained in step S3 is subjected to primary cold forging using a 1T air hammer to obtain a primary cold-forged copper-zirconium alloy, and the primary cold-forged copper-zirconium alloy is subjected to heat treatment;

[0016] S5, secondary cold forging and aging heat treatment:

[0017] The copper-zirconium alloy obtained in step S4 is subjected to secondary cold forging, i.e. upsetting and trimming, to obtain a secondary cold-forged copper-zirconium alloy, and the secondary cold-forged copper-zirconium alloy is subjected to aging heat treatment to obtain an aged copper-zirconium alloy blank. The aged copper-zirconium alloy blank is subjected to turning to obtain a copper-zirconium alloy ring.

[0018] Further, in step S1, the Cu and Zr are added to the vacuum medium-frequency induction furnace in the form of electrolytic copper plate and copper-zirconium intermediate alloy, and the Zn is added in the form of zinc block.

[0019] Note: The copper-zirconium intermediate alloy is a high-quality metal material with excellent mechanical properties and chemical stability; the electrolytic copper plate has high copper content and less impurities.

[0020] Further, in step S4, the heat treatment is aging heat treatment, i.e. the primary cold-forged copper-zirconium alloy blank is heated to 420-500℃ at a heating rate of 9-11℃ / min, kept for 1-4h, and then cooled to 50-100℃ in the furnace and discharged.

[0021] Note: The aging heat treatment promotes the precipitation of the second phase in the material, thereby improving the hardness and strength.

[0022] Further, in step S4, the heat treatment is annealing heat treatment, that is, the once cold-forged copper-zirconium alloy blank is heated to 420-500 DEG C at a heating rate of 9-11 DEG C / min, and held for 1-4 h, and then cooled to 50-100 DEG C in the furnace and discharged.

[0023] Description: The annealing heat treatment promotes the recovery recrystallization of the structure, and good plasticity and toughness are obtained.

[0024] Further, in step S5, the aging heat treatment is specifically as follows: the twice cold-forged copper-zirconium alloy blank is heated to 400-450 DEG C at a heating rate of 9-11 DEG C / min, and held for 2-5 h, and then cooled to 50-100 DEG C in the furnace and discharged.

[0025] Description: After the aging heat treatment, the hardness and strength of the copper-zirconium alloy are further improved.

[0026] Further, in step S5, the turning is that the aged copper-zirconium alloy blank is turned on a lathe to perform rough turning and finish turning, and the size is processed to be within the tolerance range of ±0.2 mm required by the process.

[0027] Description: The turning has high efficiency, high machining precision and stable quality.

[0028] Further, it further includes step S6, that is, the copper-zirconium alloy ring is subjected to corrosion protection treatment, including the following steps:

[0029] S6-1, first, the copper-zirconium alloy ring is placed in the corrosion protection treatment liquid and spontaneously immersed for 10-15 min, and then subjected to low-temperature heat treatment to complete the first corrosion protection;

[0030] The low-temperature heat treatment has a temperature of 205-210 DEG C and a holding time of 2-3 h;

[0031] S6-2, the copper-zirconium alloy ring is then placed in the corrosion protection treatment liquid under a pressure of -0.1-0.2 MPa to perform pressurized immersion, and after the pressurized immersion, subjected to temperature-variable heat treatment to complete the second corrosion protection;

[0032] The temperature-variable heat treatment is as follows: first, held at 230-240 DEG C for 15-20 min, and then heated to 350-380 DEG C at a heating rate of 5-10 DEG C / min, and held for 50-60 min.

[0033] Description: By corrosion protection treatment of copper-zirconium alloy ring, a protective film layer is formed on the surface of the copper-zirconium alloy ring, which plays a role in preventing corrosion; first, spontaneous immersion can cover the entire surface of the copper-zirconium alloy ring, providing comprehensive protection, then through low-temperature heat treatment to improve the reactivity to improve the spontaneous immersion effect; then through pressurized immersion, the corrosion-resistant liquid fully penetrates the surface of the object, forming a uniform corrosion-resistant film, and through variable temperature heat treatment, further stabilizing the corrosion resistance.

[0034] Further, the corrosion protection treatment liquid comprises 15-20 parts by mass of benzotriazole, 7-9 parts of oleylamine, 8-9 parts of sodium molybdate, 5-6 parts of zinc nitrate hexahydrate, 0.5-1 parts of propylene oxide and 3-4 parts of water.

[0035] Description: By combining the above-mentioned corrosion inhibition component and the stability component, the stability of the formed corrosion-resistant film is further enhanced while the corrosion protection effect is achieved.

[0036] Further, in step S2, after casting is completed, an antioxidant treatment is performed to obtain a copper-zirconium alloy ingot;

[0037] The antioxidant treatment is performed in the following manner: first, the cast ingot after casting is immersed in liquid carbon dioxide at a temperature of -65 to -70℃ for 2-3h, then the immersed ingot is taken out and pickled with a phosphoric acid solution with a mass concentration of 15-20% for 10-15min, after pickling, an antioxidant coating with a thickness of 0.30-0.35mm is applied to the surface, and the coated ingot is baked at a low temperature of 70-90℃ for 5-6h to obtain an antioxidant-treated ingot.

[0038] Description: By low-temperature treatment in low-temperature liquid refrigerant, i.e. carbon dioxide and liquid nitrogen, the microstructure of copper-zirconium alloy is further refined and homogenized, and with the increase of antioxidant treatment time, the degree of refinement and homogenization is continuously improved;

[0039] After the temperature is reduced, pickling is performed to achieve the purpose of rust removal and scale removal, then an antioxidant coating is applied to the surface of the copper-zirconium ingot and low-temperature baking is performed, at the end of the baking temperature, due to the good thermal conductivity and suitable thermal expansion coefficient of the coating, the coating has the characteristics of not easy to flow and good adhesion, and with the continuous reduction of the final forging temperature, the antioxidant coating can fall off the surface of the copper-zirconium alloy.

[0040] Further, the antioxidant coating comprises, by mass fraction: 8-9 parts of magnesia, 1-3 parts of chromium sesquioxide, 1-3 parts of sodium tripolyphosphate, 2-3 parts of industrial aluminum powder, 0.2-0.5 parts of solid powder of boron nitride, and 2.5-3.5% of polyacrylamide based on the mass of the solid powder, 2-3% of silica sol solution, and 20-30% of water.

[0041] Description: A coating with a wide oxidation temperature range is prepared by using a system of magnesium oxide and chromium trioxide and silica sol together; the above materials generate a dense coating at high temperature, and the adhesion is good, and can be removed after subsequent forging is completed.

[0042] The application of the copper-zirconium alloy ring piece prepared by the method, the copper-zirconium alloy ring piece is applied to a squirrel-cage asynchronous motor end ring product.

[0043] The beneficial effects of the present application are:

[0044] (1) The preparation method can obtain a relatively pure CuZr alloy material by adding a trace amount of Zn and combining with a specific preparation process, the tensile strength and electrical conductivity of the CuZr alloy can reach more than 400 MPa and 90% IACS respectively, the strength and electrical conductivity of the CuZr alloy are well matched, and the CuZr alloy can be applied to a squirrel-cage asynchronous motor end ring product.

[0045] (2) The CuZr alloy material obtained by the preparation method has higher electrical conductivity than silicon bronze; compared with pure copper, the strength and softening resistance temperature of the CuZr alloy are higher, and the electrical conductivity is only second to pure copper and silver copper; in summary, the CuZr alloy can be used to replace pure copper end ring and applied to motor rotor winding. DETAILED DESCRIPTION

[0046] The present application will be further described in detail below in combination with specific embodiments to better embody the advantages of the present application.

[0047] Example 1

[0048] A preparation method of a copper-zirconium alloy ring piece, comprising the following steps:

[0049] S1, melting:

[0050] The raw materials include the following components in terms of mass ratio: 0.15wt.% of Zr, 0.02wt.% of Zn, 0.001wt.% of Si, 0.005wt.% of Fe, 0.005wt.% of Mn, 0.005wt.% of Pb, and the balance of Cu;

[0051] The Cu and Zr are placed in the form of electrolytic copper plate and copper-zirconium intermediate alloy, and the Zn is placed in the form of zinc block into a vacuum medium-frequency induction furnace for melting, the melting temperature is 1350 DEG C, the melting time is 35 min, and the alloy melt is obtained by keeping degassing and deoxidation during the melting process;

[0052] S2, casting:

[0053] The alloy solution is cast by using a bottom casting system, the casting temperature is 1275 DEG C, a Ф155mm copper-zirconium alloy ingot is obtained, and the ingot is turned to remove surface defects;

[0054] S3, hot forging and solid solution treatment:

[0055] According to the weight of the finished copper-zirconium alloy ring, the copper-zirconium alloy ingot is sawn and cut, the weight of the cut ingot is 18.8 kg, the sawn ingot is heated to 925 DEG C, the heating time is 45 min, and the temperature is kept for 45 min; then the forging clamp is preheated to 300 DEG C, and then 1T air hammer is used for upsetting-punching-holing, the initial forging temperature is 875 DEG C, and the final forging temperature is 650 DEG C, and the hot forging process is completed The hot forging ingot is obtained.

[0056] The upsetting-punching-holing treatment is specifically: punching is performed using a Ф85mm punch, Ф80mm mandrel is used for hole expansion to Ф150mm, flat end face, and then Ф140mm mandrel is used for hole expansion to 160mm.

[0057] The forging ingot is heated to 930 DEG C at a heating rate of 22 DEG C / min, and kept for 75 min, and after the temperature is kept, the blank is taken out of the furnace and water-cooled to room temperature, and a supersaturated copper-zirconium alloy blank is obtained.

[0058] S4, primary cold forging and heat treatment:

[0059] The supersaturated copper-zirconium alloy blank obtained in step S3 is subjected to primary cold forging using a 1T air hammer to obtain a primary cold forged copper-zirconium alloy, and the size is The primary cold forged copper-zirconium alloy is subjected to heat treatment.

[0060] The heat treatment is aging heat treatment, that is, the primary cold forged copper-zirconium alloy blank is heated to 460 DEG C at a heating rate of 10 DEG C / min, kept for 2.5h, and after the temperature is kept, the furnace is cooled to 75 DEG C and taken out of the furnace;

[0061] S5, secondary cold forging and aging heat treatment:

[0062] The copper-zirconium alloy obtained in step S4 is subjected to secondary cold forging, that is, upsetting and trimming, to obtain a secondary cold forged copper-zirconium alloy, and the size is The secondary cold forged copper-zirconium alloy is subjected to aging heat treatment to obtain a copper-zirconium ring.

[0063] The aging heat treatment is specifically: the secondary cold forged copper-zirconium alloy blank is heated to 425 DEG C at a heating rate of 10 DEG C / min, kept for 3.5h, and after the temperature is kept, the furnace is cooled to 75 DEG C and taken out of the furnace, and a aged copper-zirconium alloy blank is obtained.

[0064] The aged copper-zirconium alloy blank is rough-turned and fine-turned on a lathe, and its size is processed to be within the 0.2mm tolerance range required by the process;

[0065] The copper-zirconium alloy ring described above is applied to the end ring product of a squirrel-cage asynchronous motor.

[0066] Example 2

[0067] The difference between this example and Example 1 is that the raw materials include the following components by mass ratio: 0.13wt.% of Zr, 0.02wt.% of Zn, 0.001wt.% of Si, 0.005wt.% of Fe, 0.005wt.% of Mn, 0.005wt.% of Pb, and the balance of Cu.

[0068] Example 3

[0069] The difference between this example and Example 1 is that the raw materials include the following components by mass ratio: 0.18wt.% of Zr, 0.02wt.% of Zn, 0.001wt.% of Si, 0.005wt.% of Fe, 0.005wt.% of Mn, 0.005wt.% of Pb, and the balance of Cu.

[0070] Example 4

[0071] The difference between this example and Example 1 is that, in step S1, the melting temperature is 1300℃, and the melting time is 30min.

[0072] Example 5

[0073] The difference between this example and Example 1 is that, in step S1, the melting temperature is 1400℃, and the melting time is 40min.

[0074] Example 6

[0075] The difference between this example and Example 1 is that, in step S2, the pouring temperature is 1250℃.

[0076] Example 7

[0077] The difference between this example and Example 1 is that, in step S2, the pouring temperature is 1300℃.

[0078] Example 8

[0079] The difference between this example and Example 1 is that, in step S3, the sawed ingot is heated to 900℃, the heating time is 30min, and the holding time is 30min; and the forging clamp is preheated to 250℃.

[0080] Example 9

[0081] The difference between this embodiment and embodiment 1 is that in step S3, the sawed ingot is heated to 950℃, the heating time is 60 min, and the holding time is 60 min; and the forging clamp is preheated to 350℃.

[0082] Embodiment 10

[0083] The difference between this embodiment and embodiment 1 is that in step S3, the initial forging temperature is 850℃, and the final forging temperature is 640℃.

[0084] Embodiment 11

[0085] The difference between this embodiment and embodiment 1 is that in step S3, the initial forging temperature is 900℃, and the final forging temperature is 660℃.

[0086] Embodiment 12

[0087] The difference between this embodiment and embodiment 1 is that in step S3, the forged ingot is heated to 900℃ at a heating rate of 19℃ / min, and the holding time is 60 min.

[0088] Embodiment 13

[0089] The difference between this embodiment and embodiment 1 is that in step S3, the forged ingot is heated to 960℃ at a heating rate of 25℃ / min, and the holding time is 90 min.

[0090] Embodiment 14

[0091] The difference between this embodiment and embodiment 1 is that in step S4, the heat treatment is aging heat treatment, i.e. the primary cold-forged copper-zirconium alloy blank is heated to 420℃ at a heating rate of 9℃ / min, the holding time is 1 h, and after the holding is completed, the blank is cooled to 50℃ in the furnace and taken out.

[0092] Embodiment 15

[0093] The difference between this embodiment and embodiment 1 is that in step S4, the heat treatment is aging heat treatment, i.e. the primary cold-forged copper-zirconium alloy blank is heated to 500℃ at a heating rate of 11℃ / min, the holding time is 4 h, and after the holding is completed, the blank is cooled to 100℃ in the furnace and taken out.

[0094] Embodiment 16

[0095] The difference between this embodiment and embodiment 1 is that in step S4, the heat treatment is annealing heat treatment, i.e. the primary cold-forged copper-zirconium alloy blank is heated to 460℃ at a heating rate of 10℃ / min, the holding time is 2.5 h, and after the holding is completed, the blank is cooled to 75℃ in the furnace and taken out.

[0096] Embodiment 17

[0097] The difference between the embodiment and embodiment 16 is that in step S4, the heat treatment is annealing heat treatment, that is, the once cold-forged copper-zirconium alloy blank is heated to 420 DEG C at a heating rate of 9 DEG C / min, and held for 1 h, and then furnace-cooled to 50 DEG C after holding and discharged from the furnace.

[0098] Embodiment 18

[0099] The difference between the embodiment and embodiment 16 is that in step S4, the heat treatment is annealing heat treatment, that is, the once cold-forged copper-zirconium alloy blank is heated to 420 DEG C at a heating rate of 9 DEG C / min, and held for 1 h, and then furnace-cooled to 50 DEG C after holding and discharged from the furnace.

[0100] Embodiment 19

[0101] The difference between the embodiment and embodiment 1 is that in step S5, the aging heat treatment is specifically as follows: the twice cold-forged copper-zirconium alloy blank is heated to 400 DEG C at a heating rate of 9 DEG C / min, and held for 2 h, and then furnace-cooled to 50 DEG C after holding and discharged from the furnace.

[0102] Embodiment 20

[0103] The difference between the embodiment and embodiment 1 is that in step S5, the aging heat treatment is specifically as follows: the twice cold-forged copper-zirconium alloy blank is heated to 450 DEG C at a heating rate of 11 DEG C / min, and held for 5 h, and then furnace-cooled to 100 DEG C after holding and discharged from the furnace.

[0104] Embodiment 21

[0105] The difference between the embodiment and embodiment 1 is that step S6 is included, that is, the copper-zirconium alloy ring is subjected to corrosion protection treatment, including the following steps:

[0106] S6-1, first, the copper-zirconium alloy ring is placed in a corrosion protection treatment liquid for spontaneous immersion for 13 min, and then subjected to low-temperature heat treatment to complete the first corrosion protection;

[0107] The temperature of the low-temperature heat treatment is 208 DEG C, and the holding time is 2.5 h;

[0108] S6-2, then, the copper-zirconium alloy ring is placed in the corrosion protection treatment liquid under pressure for pressure immersion at 0.1 MPa, and then subjected to temperature-variable heat treatment after pressure immersion to complete the second corrosion protection;

[0109] The temperature-variable heat treatment is as follows: first, holding at 235 DEG C for 18 min, and then increasing the temperature to 365 DEG C at a heating rate of 8 DEG C / min, and holding for 55 min;

[0110] The corrosion protection treatment liquid includes 18 parts of benzotriazole, 8 parts of oleylamine, 8.5 parts of sodium molybdate, 5.5 parts of zinc nitrate hexahydrate, 0.8 parts of propylene oxide, and 3.5 parts of water in terms of mass fraction.

[0111] Example 22

[0112] The difference between this example and Example 21 is that the corrosion treatment solution comprises 15 parts of benzotriazole, 7 parts of oleylamine, 8 parts of sodium molybdate, 5 parts of zinc nitrate hexahydrate, 1 part of propylene oxide and 3 parts of water by mass fraction.

[0113] Example 23

[0114] The difference between this example and Example 21 is that the corrosion treatment solution comprises 20 parts of benzotriazole, 9 parts of oleylamine, 9 parts of sodium molybdate, 6 parts of zinc nitrate hexahydrate, 0.5 parts of propylene oxide and 4 parts of water by mass fraction.

[0115] Example 24

[0116] The difference between this example and Example 21 is that the time of spontaneous immersion and pressure immersion is 10 min, and the pressure of pressure immersion is 0.2 MPa.

[0117] Example 25

[0118] The difference between this example and Example 21 is that the time of spontaneous immersion and pressure immersion is 15 min, and the pressure of pressure immersion is -0.1 MPa.

[0119] Example 26

[0120] The difference between this example and Example 21 is that in step S6-1, the temperature of low-temperature heat treatment is 205℃, and the holding time is 2h.

[0121] Example 27

[0122] The difference between this example and Example 21 is that in step S6-1, the temperature of low-temperature heat treatment is 210℃, and the holding time is 3h.

[0123] Example 28

[0124] The difference between this example and Example 21 is that in step S6-2, the temperature change heat treatment is: first holding at 230℃ for 15 min, then increasing to 350℃ at a rate of 5℃ / min, and holding for 50 min.

[0125] Example 29

[0126] The difference between this example and Example 21 is that in step S6-2, the temperature change heat treatment is: first holding at 240℃ for 20 min, then increasing to 380℃ at a rate of 10℃ / min, and holding for 60 min.

[0127] Example 30

[0128] The difference between the present embodiment and embodiment 1 is that in step S2, an antioxidation treatment is performed after the casting is completed, to obtain a copper-zirconium alloy ingot;

[0129] The antioxidation treatment is performed in the following manner: the cast ingot after the casting is completed is immersed in liquid carbon dioxide at a temperature of -68°C for 2.5 h, then the immersed ingot is taken out and pickled in a phosphoric acid solution with a mass concentration of 18% for 12 min, after the pickling is completed, an antioxidation coating with a thickness of 0.32 mm is coated on the surface of the ingot, and the coated ingot is baked at a low temperature of 80°C for 5.5 h, to obtain an ingot after the antioxidation treatment is completed;

[0130] The antioxidation coating comprises, in terms of mass fraction: 8.5 parts of magnesia, 2 parts of chromium sesquioxide, 2 parts of sodium tripolyphosphate, 2.5 parts of industrial aluminum powder, 0.3 parts of solid powder of boron nitride, and 3.0% of polyammonium acrylate, 2.5% of silica sol solution, and 25% of water, based on the mass of the solid powder.

[0131] Embodiment 31

[0132] The difference between the present embodiment and embodiment 30 is that the cast ingot after the casting is completed is immersed in liquid carbon dioxide at a temperature of -70°C for 2 h.

[0133] Embodiment 32

[0134] The difference between the present embodiment and embodiment 30 is that the cast ingot after the casting is completed is immersed in liquid carbon dioxide at a temperature of -65°C for 3 h.

[0135] Embodiment 33

[0136] The difference between the present embodiment and embodiment 21 is that the immersed ingot is taken out and pickled in a phosphoric acid solution with a mass concentration of 15% for 10 min.

[0137] Embodiment 34

[0138] The difference between the present embodiment and embodiment 30 is that the immersed ingot is taken out and pickled in a phosphoric acid solution with a mass concentration of 20% for 15 min.

[0139] Embodiment 35

[0140] The difference between the present embodiment and embodiment 30 is that after the pickling is completed, an antioxidation coating with a thickness of 0.30 mm is coated on the surface of the ingot, and the coated ingot is baked at a low temperature of 70°C for 5 h.

[0141] Embodiment 36

[0142] The present example differs from Example 30 in that after the acid washing is completed, an antioxidant coating having a thickness of 0.35 mm is applied to the surface thereof, and the coated ingot is baked at a low temperature of 90°C for 6 hours.

[0143] Example 37

[0144] The present example differs from Example 30 in that the antioxidant coating includes, by mass fraction: 9 parts of magnesia, 1 part of chromium sesquioxide, 1 part of sodium tripolyphosphate, 2 parts of industrial aluminum powder, 0.2 parts of solid powder of boron nitride, and 2.5% of polyacrylammonium, 2% of silica sol solution, and 30% of water, based on the mass of the solid powder.

[0145] Example 38

[0146] The present example differs from Example 30 in that the antioxidant coating includes, by mass fraction: 8 parts of magnesia, 3 parts of chromium sesquioxide, 3 parts of sodium tripolyphosphate, 3 parts of industrial aluminum powder, 0.5 parts of solid powder of boron nitride, and 3.5% of polyacrylammonium, 3% of silica sol solution, and 20% of water, based on the mass of the solid powder.

[0147] Experimental Example

[0148] For each of the prepared copper-zirconium alloy ring pieces, 5 samples of each example were taken to test the performance of the copper-zirconium alloy ring pieces, and the performance measurement results of the 5 samples of each example were averaged to serve as the performance measurement results of the example, and the specific exploration is as follows:

[0149] 1. Explore the influence of each step in the preparation process on the tensile strength and electrical conductivity of the copper-zirconium alloy ring piece.

[0150] Table 1 Influence of Examples 1-29 and Comparative Examples 1-3 on the tensile strength (MPa) and electrical conductivity (%IACS) of the copper-zirconium alloy ring piece

[0151]

[0152]

[0153] Comparative Example 1 differs from Example 1 in that a pure copper ring piece is selected for preparation;

[0154] As can be seen from the results in Table 1, in Comparative Example 1, the zirconium element is absent, and compared with Examples 1-20, the electrical conductivity is significantly enhanced, but the tensile strength is significantly reduced, and the reduction amplitude of the tensile strength is greater than the increase amplitude of the electrical conductivity, so the overall effect of Comparative Example 1 is poorer than that of Examples 30-38.

[0155] From Comparative Examples 1 to 20, it can be seen that the tensile strength of Comparative Examples 16 to 18 is significantly improved but the electrical conductivity is significantly reduced, and the overall effect is poorer than that of the remaining examples; compared with the remaining examples, the proportion of zirconium in the raw materials is too low or too high, the casting temperature is too low or too high, the preheating temperature is too low or too high, the temperature during hot forging is too low or too high, the solid solution temperature in Examples 12 to 13 is too high and the holding time is too long, the aging temperature in Examples 14 to 15 and Examples 19 to 20 is too high and the holding time is too long, all of which reduce the tensile strength and electrical conductivity of the copper-zirconium alloy ring, but the tensile strength of the copper-zirconium alloy ring is slightly improved and the electrical conductivity is slightly reduced compared with Example 1, and compared with the remaining examples, the overall effect of Example 1 is relatively better.

[0156] For the copper-zirconium alloy ring prepared in Examples 1, 21 to 29, 5 samples of each example were taken for salt spray corrosion test to test the corrosion resistance, and the performance measurement results of the 5 samples of each example were averaged as the performance measurement results of the example, and the specific exploration is as follows:

[0157] 2. Explore the effect of each step in the corrosion treatment on the corrosion rate of the copper-zirconium alloy ring.

[0158] Table 2 Influence of Examples 1, 21 to 29 and Comparative Examples 2 to 4 on the corrosion rate g / (m 2 ·h) of the copper-zirconium alloy ring

[0159]

[0160] Comparative Example 2 differs from Example 21 in that in step S6-2, it is also spontaneous immersion, and the pressure is kept consistent with step S6-1;

[0161] Comparative Example 3 differs from Example 21 in that in step S6-2, the temperature of the heat treatment is kept at 365℃ without temperature change;

[0162] Comparative Example 4 differs from Example 21 in that the corrosion treatment liquid does not contain propylene oxide;

[0163] From the results in Table 2, it can be seen that Comparative Example 2 lacks pressure change during immersion, Comparative Example 3 lacks temperature change, and Comparative Example 4 lacks propylene oxide in the corrosion treatment liquid, and the corrosion effect is less improved than that of Example 1, and the corrosion effect is significantly reduced compared with Examples 21 to 29;

[0164] and Comparative Example 1, Examples 21-29, it can be seen that the corrosion resistance of the copper-zirconium alloy ring part after the corrosion prevention treatment is significantly improved compared with Example 1, and from Comparative Examples 21-29, it can be seen that too low or too high proportion of propylene oxide in the corrosion prevention treatment liquid, too short or too long time of spontaneous immersion and pressure immersion, too low parameters of low-temperature heat treatment and variable-temperature heat treatment will reduce the effect of the corrosion prevention treatment, and the temperature of Example 27 and Example 29 is higher and the holding time is longer, but the improvement compared with Example 21 is smaller, therefore, from the economic point of view, the corrosion resistance of the copper-zirconium alloy ring part prepared by the parameters of Example 21 is the best.

[0165] 3. Explore the influence of each step in the antioxidant treatment on the tensile strength and electrical conductivity of the copper-zirconium alloy ring part. Table 3 Examples 30-38 and Comparative Examples 5-6 on the tensile strength (MPa) and electrical conductivity (%IACS) of the copper-zirconium alloy ring part

[0166]

[0167] Comparative Example 5 differs from Example 21 in that it is not immersed in liquid carbon dioxide for cooling, but is cooled at room temperature;

[0168] Comparative Example 6 differs from Example 21 in that it is not acid washed;

[0169] From the results in Table 3, it can be seen that Comparative Example 5 lacks cryogenic treatment, and Comparative Example 6 lacks acid washing, both of which have a decrease in tensile strength and electrical conductivity compared with Examples 30-38;

[0170] From Table 1 and Table 3, Comparative Example 1, Examples 30-38, it can be seen that after cryogenic treatment and acid washing, the overall improvement effect of coating the antioxidant coating on the copper-zirconium alloy ring part is better than that of Example 1; from Comparative Examples 30-38, too low or too high immersion parameters, too low or too high acid washing parameters, too low or too high antioxidant coating parameters, and too low or too high proportion of magnesia in the antioxidant coating will reduce the overall improvement effect on the copper-zirconium alloy ring part, therefore, the effect of the copper-zirconium alloy ring part prepared by the parameters of Example 30 is relatively better.

Claims

1. A method for preparing a copper-zirconium alloy ring, characterized in that, Includes the following steps: S1, Smelting: The raw materials, by mass ratio, include the following components: 0.13~0.18 wt.% Zr, Zn≤0.02 wt.%, with the balance being Cu; The above raw materials are placed in a vacuum medium-frequency induction furnace for melting. The melting temperature is 1300~1400℃ and the melting time is 30~40min. During the melting process, degassing and deoxidation are maintained to obtain alloy melt. S2, Casting: The alloy solution was cast using a bottom casting system at a casting temperature of 1250~1300℃ to obtain a copper-zirconium alloy ingot, which was then machined to remove surface defects. S3, hot forging and solution treatment: Based on the finished weight of the copper-zirconium alloy ring, the copper-zirconium alloy ingot is sawn and cut. The sawn ingot is heated to 900~950℃ for 30~60min and held at that temperature for 30~60min. The forging fixture is then preheated to 250~350℃, and then upsetting, punching, and reaming are performed using a 1T air hammer. During the hot forging process, the initial forging temperature is 850~900℃ and the final forging temperature is 640~660℃. After the hot forging is completed, a hot forged ingot blank that meets the requirements is obtained. The hot forged billet is heated to 900-960℃ at a heating rate of 19-25℃ / min and held for 60-90min. After the holding period, the billet is removed from the furnace and cooled to room temperature with water to obtain a supersaturated copper-zirconium alloy. S4, One-time cold forging and heat treatment: The supersaturated copper-zirconium alloy obtained in step S3 is cold-forged once using a 1T air hammer to obtain a cold-forged copper-zirconium alloy, and then the cold-forged copper-zirconium alloy is heat-treated once. S5, secondary cold forging and aging heat treatment: The cold-forged copper-zirconium alloy obtained in step S4 is subjected to secondary cold forging, namely upsetting and trimming, to obtain a secondary cold-forged copper-zirconium alloy. The secondary cold-forged copper-zirconium alloy is then subjected to aging heat treatment to obtain an aged copper-zirconium alloy. The aged copper-zirconium alloy is then machined to obtain a copper-zirconium alloy ring. S6. Perform anti-corrosion treatment on the copper-zirconium alloy ring, including the following steps: S6-1. First, place the copper-zirconium alloy ring in the anti-corrosion treatment solution and immerse it spontaneously for 10-15 minutes, then perform low-temperature heat treatment to complete one anti-corrosion treatment. The low-temperature heat treatment is performed at a temperature of 205~210℃ for 2~3 hours. S6-2. Next, immerse the copper-zirconium alloy ring in the anti-corrosion solution at -0.1~0.2MPa for 10~15 minutes. After the pressure immersion is completed, perform variable temperature heat treatment to complete the secondary anti-corrosion. The variable temperature heat treatment is as follows: first, hold at 230~240℃ for 15~20min, then raise the temperature to 350~380℃ at a heating rate of 5~10℃ / min and hold for 50~60min; The anti-corrosion treatment solution comprises, by weight, 15-20 parts benzotriazole, 7-9 parts oleylamine, 8-9 parts sodium molybdate, 5-6 parts zinc nitrate hexahydrate, 0.5-1 parts propylene oxide, and 3-4 parts water.

2. The method for preparing a copper-zirconium alloy ring according to claim 1, characterized in that, In step S1, Cu and Zr are added to the vacuum intermediate frequency induction furnace in the form of electrolytic copper plates and copper-zirconium master alloys, and Zn is added in the form of zinc blocks.

3. The method for preparing a copper-zirconium alloy ring according to claim 1, characterized in that, In step S4, the heat treatment is an aging heat treatment, which involves heating the cold-forged copper-zirconium alloy to 420-500℃ at a heating rate of 9-11℃ / min, holding it at that temperature for 1-4 hours, and then cooling it to 50-100℃ in the furnace after holding.

4. The method for preparing a copper-zirconium alloy ring according to claim 1, characterized in that, In step S4, the heat treatment is annealing heat treatment, which involves heating the cold-forged copper-zirconium alloy to 420-500℃ at a heating rate of 9-11℃ / min, holding it at that temperature for 1-4 hours, and then cooling it in the furnace to 50-100℃ after holding.

5. The method for preparing a copper-zirconium alloy ring according to claim 1, characterized in that, In step S5, the aging heat treatment specifically involves heating the secondary cold-forged copper-zirconium alloy to 400-450°C at a heating rate of 9-11°C / min, holding it at that temperature for 2-5 hours, and then cooling it to 50-100°C in the furnace after holding.

6. The method for preparing a copper-zirconium alloy ring according to claim 1, characterized in that, In step S5, the machining process involves roughing and finishing the aged copper-zirconium alloy on a lathe and machining its dimensions to the tolerance range of ±0.2mm required by the process.

7. The application of a copper-zirconium alloy ring prepared by the preparation method according to any one of claims 1 to 6, characterized in that, The copper-zirconium alloy ring is used in end ring products for squirrel-cage asynchronous motors.

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