CN110408812B - Preparation method for squirrel-cage asynchronous traction motor end ring - Google Patents
Preparation method for squirrel-cage asynchronous traction motor end ring Download PDFInfo
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Abstract
The invention discloses a preparation method for a squirrel-cage asynchronous traction motor end ring, which comprises the following steps of S1: selecting and weighing corresponding raw materials according to the chemical compositions and the weight percentages of the chemical compositions of the Cu-Cr-Zr copper alloy end ring; s2: smelting each raw material by adopting a vacuum medium-frequency induction furnace, and after all alloy elements are smelted, casting to obtain the required ingot casting specification; s3: forging the obtained cast ingot, wherein the forging comprises heating, cake upsetting, punching, hole expanding and plane surface; s4: carrying out solution treatment on the end ring obtained by forging; carrying out aging treatment on the end ring obtained by solid solution; s5: and after the end ring obtained by the aging treatment is subjected to rough machining, sequentially carrying out performance detection, machining and finished product detection to obtain a finished end ring. The end ring has higher strength, higher elongation and higher conductivity, and can meet the requirements of high power and high rotating speed of an asynchronous traction rotor.
Description
Technical Field
The invention relates to the technical field of manufacturing of a motor rotor of a rail transit, in particular to a preparation method for an end ring of a squirrel-cage asynchronous traction motor.
Background
With the development of the field of rail transit and high-speed rail, the rotating speed and power of a traction motor are also continuously improved, so that the requirement on a core component of the motor, namely a motor rotor, is higher and higher; the manufacturing technology of the general high-speed asynchronous traction motor rotor adopts a conducting bar to be embedded on an iron core and welded with an end ring; the rotor is subjected to comprehensive effects of thermal stress, electromagnetic stress, mechanical stress, residual stress, dynamic stress and the like in the operation process, and when various stresses are overlarge, the damage to the end ring is large.
Meanwhile, the Cu-HCP end ring has higher conductivity due to the fact that the material of the Cu-HCP end ring is pure copper, the conductivity reaches 57MS/m, but the tensile strength is about 200MPa and lower due to the fact that the pure copper material does not have a strengthening phase; on the other hand, the temperature rise of the motor rotor is high during the motor operation, which usually exceeds 200 ℃, and the strength of the material is reduced obviously when the material is used at a higher temperature. Considering the use environment of the end ring, high conductivity and high strength are very important design parameters, so that a protective ring is generally designed to be sleeved on the end ring outside the Cu-HCP end ring, the self weight of the motor is increased, and the load of the motor is increased; and the design of the end ring and the protective ring also increases the manufacturing cost of the motor.
In addition, when the end ring is used, the end ring needs to be in braze welding connection with the guide bar, the groove-shaped part of the end ring is designed into an annular groove on the end face of the ring, more solder is needed during braze welding, and the silver solder is adopted as a common solder material, so that the cost of the motor is increased.
Accordingly, there is a need for a high strength, high conductivity end ring for a squirrel cage asynchronous traction motor that addresses these problems.
Disclosure of Invention
In order to solve the technical problem, the invention provides a preparation method for an end ring of a squirrel-cage asynchronous traction motor.
The technical scheme of the invention is that the preparation method for the squirrel-cage asynchronous traction motor end ring mainly comprises the following steps:
s1: selecting and weighing corresponding raw materials according to the chemical compositions and the weight percentage of the Cu-Cr-Zr copper alloy end ring;
s2: smelting the raw materials, adding the raw materials during smelting, and ensuring that the vacuum degree is lower than 5Pa during smelting; after all alloy elements are smelted, casting to obtain the required ingot casting specification; the vacuum intermediate frequency induction furnace smelting method has the advantages that: 1. the whole process of melting, refining and alloying of the metal is carried out in a vacuum state, so that pollution caused by interaction of the same gas phase is avoided; 2. under the vacuum condition, the zirconium has strong deoxidizing capacity, other deoxidizing agents do not need to be added, and the pollution problem caused by the adoption of a metal deoxidizing agent for deoxidation is solved; 3. the vacuum induction melting furnace process can accurately control the chemical components of the alloy, can control active elements such as Al, Ti, B and the like with strong affinity with oxygen and nitrogen in a small range, and can evaporate and remove low-melting-point volatile metal impurities such as Pb, Bi, Sn, Sb and the like, thereby playing an important role in improving the performance of materials.
S3: forging the obtained cast ingot, wherein the forging comprises heating, cake upsetting, punching, hole expanding and plane surface;
s4: carrying out solid solution treatment on the end ring obtained by forging, controlling the solid solution temperature to be 950 +/-30 ℃, keeping the temperature for 1-2h, and cooling by water; carrying out aging treatment on the end ring obtained by solid solution, controlling the aging temperature to be 430 +/-30 ℃, keeping the temperature for 3-5h, and cooling by air; through solution and aging treatment, the alloy can be fully strengthened, and higher mechanical properties can be obtained.
S5: and after the end ring obtained by the aging treatment is roughly processed, the rough processing mainly removes most of cutting allowance, ensures that the surface roughness meets the requirement, and sequentially performs performance detection, machining and finished product detection to obtain the finished end ring.
Further, the chemical composition and weight percentage of the Cu-Cr-Zr copper alloy end ring are as follows: cr: 0.5-1.2%; zr: 0.03-0.3%; fe is less than or equal to 0.08 percent; si is less than or equal to 0.1 percent; others are less than or equal to 0.2 percent; cu: and (4) the balance. Impurities such as Fe, Si and the like are specified, the electrical property of the end ring is better, and Fe and Si influence the conductivity of the material.
Further, the smelting is carried out by adopting a vacuum intermediate frequency induction furnace, and the adding mode of each raw material is as follows: cu is added in an electrolytic copper plate mode, and Cr and Zr are added in an intermediate alloy mode. Through vacuum induction melting treatment, the content of O (oxygen) in the material is lower, low-melting-point impurity elements such as zinc, lead, tin and the like are volatile, and the purity of the material is higher.
Further, as another technical scheme of the invention, the smelting specifically comprises: 1) equally dividing an electrolytic copper plate into 2 parts, electrolyzing one part of the electrolytic copper plate, placing the electrolytic copper plate in a crucible of a vacuum intermediate frequency induction melting furnace, vacuumizing, adding a Cr intermediate alloy into the crucible of the vacuum intermediate frequency induction melting furnace, ensuring that the vacuum degree is lower than 5Pa in the melting process, controlling the melting power to be 310 and 340kW, reacting for 15-25min, preserving the heat for 25-35min, and then casting into a Cu-Cr ingot; 2) electrolyzing the other part of the electrolytic copper plate, adding the other part of the electrolytic copper plate into a crucible of an electron beam melting furnace, vacuumizing, adding Zr intermediate alloy into the crucible of the electron beam melting furnace, ensuring that the vacuum degree is lower than 1Pa in the melting process, controlling the melting power to be 250-270W, keeping the melting rate to be 21-24kg/h, preserving the temperature for 30-45min, and then casting into a Cu-Zr cast ingot; 3) carrying out electroslag remelting in an inert atmosphere by taking a Cu-Cr cast ingot as a consumable electrode, adding the Cu-Zr cast ingot into a crucible, heating until the Cu-Cr cast ingot is completely molten, slowly lowering the consumable electrode into molten liquid, electrifying to start an arc, adjusting the remelting voltage to 25-40V and the current to 3.7-6.5kA, melting and mixing the consumable electrode and the Cu-Zr, preserving the heat for 1-3h, and casting to obtain the required cast ingot specification; wherein the inert atmosphere is argon, but is not limited thereto. The Cu-Cr cast ingot is obtained by vacuum medium-frequency induction melting, the Cu-Zr cast ingot is obtained by electron beam melting, and then is subjected to mixed melting through electroslag remelting, so that the electrical property, the mechanical property and the like can be effectively improved, and the subsequently prepared end ring has higher strength, higher elongation and higher conductivity.
Furthermore, the casting temperature is 1250-1300 ℃, the casting principle is that the casting speed is firstly slow and then fast and then slow, and the later-stage slow speed is used for ensuring sufficient feeding and eliminating the metallurgical defects in the cast ingot.
Furthermore, a plurality of single grooves (2) are circumferentially arranged on the groove-shaped part (1) at the joint of the finished end ring and the guide bar at equal intervals. The groove-shaped part (1) is designed to be a single groove (2) at the joint with the conducting bar, so that the welding is convenient, and the welding flux is saved.
Further, the forging specifically includes the steps of:
(1) the heating temperature of the cast ingot is 900-950 ℃, the starting forging temperature is not lower than 850 ℃, the preheating temperature of the tool and the clamp is 250-350 ℃, and the final forging temperature is not lower than 650 ℃; the initial forging temperature is not lower than 850 ℃ and has the advantage that the material is easier to thermally deform when the initial forging temperature is 850 ℃ to 950 ℃, and the final forging temperature is not lower than 650 ℃ and has the advantage that the material is not easy to crack when the thermal deformation is carried out when the temperature is higher than 650 ℃;
(2) cake upsetting: discharging the heated cast ingot out of the furnace, and upsetting the cake, wherein the height of the upset cake is the design height of the forge piece, and the diameter of the upset cake is the free size;
(3) punching: punching the copper cake after cake upsetting, and punching a hole in the center of the copper cake by selecting a punch with a proper diameter to form a ring;
(4) reaming: reaming the punched ring, wherein the reaming diameter is the designed diameter of the forge piece;
(5) plane: and (5) carrying out plane treatment on the ring subjected to hole expansion, wherein the plane height is the design height of the forge piece. The forging method has the advantages that: 1. tools and equipment used for free forging are simple, the universality is good, excessive tools and dies are not required for products of multiple varieties and multiple specifications, and the cost is low; 2. compared with a cast end ring, the free forging eliminates the defects of shrinkage cavity, shrinkage porosity, air holes and the like, so that the end ring has higher mechanical property; 3. simple shape and flexible operation.
Further, the performance detection specifically includes: the end ring obtained by rough machining is subjected to chemical component detection, mechanical property detection, electrical property detection and ultrasonic flaw detection, the specific performance requirements are as shown in the following table 1,
table 1 end ring performance requirements (room temperature)
Further, the machining specifically comprises: and (4) finish turning the end ring qualified for detection, and then performing milling groove machining, wherein the size meets the requirement of a design drawing.
Further, the finished product detection specifically comprises: and (3) carrying out size detection on the machined end ring, detecting the appearance and boxing the end ring after the end ring is qualified in size, checking boxing information and checking the packaging box.
The invention has the beneficial effects that:
(1) the end ring has higher strength, higher elongation and higher conductivity; the copper alloy end ring can meet the requirements of high power and high rotating speed of an asynchronous traction rotor, and can stably run under severe working conditions.
(2) The copper alloy end ring designed by the invention has the advantages of low content of alloy elements, high conductivity and high tensile strength, so that the strength of the copper alloy end ring can be greatly improved without excessively sacrificing the conductivity of the copper alloy end ring, a protective ring is not required to be designed to be sleeved on the end ring in a hot manner, the conformity of a motor is reduced, and the manufacturing cost of the motor is also saved.
(3) According to the copper alloy end ring designed by the invention, the groove-shaped part is designed to be a single groove at the joint with the conducting bar, so that the welding is convenient, and the welding flux is saved.
Drawings
FIG. 1 is a schematic view of the overall structure of the end ring of the present invention, wherein 1-slot type section, 2-single slot.
FIG. 2 is a schematic diagram of the overall structure of a Cu-HCP end-ring.
FIGS. 3-4 are metallographic images of Cu-Cr-Zr copper alloy end rings at 100 Xmagnification.
Detailed Description
The technical solution of the present invention is further described in detail with reference to the following examples, but the scope of the present invention is not limited thereto.
Example 1
A preparation method for an end ring of a squirrel-cage asynchronous traction motor mainly comprises the following steps:
s1: according to the chemical compositions and weight percentages of the Cu-Cr-Zr copper alloy end ring, Cr: 0.5 percent; zr: 0.03 percent; cu: the balance, wherein the Fe content is not more than 0.08 percent, the Si content is not more than 0.1 percent, and corresponding raw materials are selected and weighed;
s2: smelting by adopting a vacuum medium-frequency induction furnace, wherein the oxygen content in the material is lower, low-melting-point impurity elements such as zinc, lead, tin and the like are volatile, the purity of the material is higher, Cu is added in an electrolytic copper plate mode during smelting, Cr and Zr are added in an intermediate alloy mode, and the vacuum degree is ensured to be lower than 5Pa in the smelting process; after all alloy elements are smelted, casting to obtain the required specification of an ingot, wherein the casting temperature is 1250 ℃, the casting principle is that the casting is performed at first slow and then fast and then slow, and the slow speed is performed at the later stage so as to ensure sufficient feeding and eliminate the metallurgical defects in the ingot; the vacuum intermediate frequency induction furnace smelting method has the advantages that: 1. the whole process of melting, refining and alloying of the metal is carried out in a vacuum state, so that pollution caused by interaction of the same gas phase is avoided; 2. under the vacuum condition, the zirconium has strong deoxidizing capacity, other deoxidizing agents do not need to be added, and the pollution problem caused by the adoption of a metal deoxidizing agent for deoxidation is solved; 3. the vacuum induction melting furnace process can accurately control the chemical components of the alloy, can control active elements such as Al, Ti, B and the like with strong affinity with oxygen and nitrogen in a small range, and can evaporate and remove low-melting-point volatile metal impurities such as Pb, Bi, Sn, Sb and the like, thereby playing an important role in improving the performance of materials.
S3: forging the obtained ingot, wherein the forging specifically comprises the following steps,
(1) heating the cast ingot at 900 ℃, forging starting temperature not lower than 850 ℃, preheating the tooling and the fixture at 250 ℃, and finish forging temperature not lower than 650 ℃; the initial forging temperature is not lower than 850 ℃ and has the advantage that the material is easier to thermally deform when the initial forging temperature is 850 ℃ to 950 ℃, and the final forging temperature is not lower than 650 ℃ and has the advantage that the material is not easy to crack when the thermal deformation is carried out when the temperature is higher than 650 ℃;
(2) cake upsetting: discharging the heated cast ingot out of the furnace, and upsetting the cake, wherein the height of the upset cake is the design height of the forge piece, and the diameter of the upset cake is the free size;
(3) punching: punching the copper cake after cake upsetting, and punching a hole in the center of the copper cake by selecting a punch with a proper diameter to form a ring;
(4) reaming: reaming the punched ring, wherein the reaming diameter is the designed diameter of the forge piece;
(5) plane: and (5) carrying out plane treatment on the ring subjected to hole expansion, wherein the plane height is the design height of the forge piece. The forging method has the advantages that: 1. tools and equipment used for free forging are simple, the universality is good, excessive tools and dies are not required for products of multiple varieties and multiple specifications, and the cost is low; 2. compared with a cast end ring, the free forging eliminates the defects of shrinkage cavity, shrinkage porosity, air holes and the like, so that the end ring has higher mechanical property; 3. the shape is simple, and the operation is flexible;
s4: carrying out solid solution treatment on the forged end ring, controlling the solid solution temperature at 920 ℃, keeping the temperature for 1h, and cooling by water; carrying out aging treatment on the end ring obtained by solid solution, wherein the aging temperature is controlled at 400 ℃, the heat preservation time is 3h, and the cooling mode adopts air cooling; through solution and aging treatment, the alloy can be fully strengthened, and higher mechanical properties can be obtained.
S5: after rough machining is carried out on the end ring obtained through ageing treatment, most of cutting allowance is mainly removed through rough machining, surface roughness is guaranteed to meet requirements, chemical composition, mechanical property, electrical property and ultrasonic flaw detection are carried out on the end ring obtained through rough machining, finish turning is carried out on the end ring qualified in detection, milling groove machining is carried out after finish turning is carried out, the size meets the requirements of design drawings, size detection is carried out on the end ring after machining, appearance is detected and boxing is carried out after the size is qualified, boxing information is checked, a packaging box is checked, a finished end ring is obtained, and a plurality of single grooves 2 are circumferentially arranged on a groove-shaped portion 1 of the joint of the finished end ring and a guide bar at equal intervals. The groove-shaped part 1 is designed to be a single groove 2 at the joint with the conducting bar, so that the welding is convenient and the welding flux is saved.
Example 2
A preparation method for an end ring of a squirrel-cage asynchronous traction motor mainly comprises the following steps:
s1: according to the chemical compositions and weight percentages of the Cu-Cr-Zr copper alloy end ring, Cr: 0.9 percent; zr: 0.25 percent; cu: the balance, wherein the Fe content is not more than 0.08 percent, the Si content is not more than 0.1 percent, and corresponding raw materials are selected and weighed;
s2: smelting by adopting a vacuum medium-frequency induction furnace, wherein the oxygen content in the material is lower, low-melting-point impurity elements such as zinc, lead, tin and the like are volatile, the purity of the material is higher, Cu is added in an electrolytic copper plate mode during smelting, Cr and Zr are added in an intermediate alloy mode, and the vacuum degree is ensured to be lower than 5Pa in the smelting process; after all alloy elements are smelted, casting to obtain the required ingot casting specification, wherein the casting temperature is 1280 ℃, the casting principle is that the casting is performed at a low speed and then at a high speed, and the casting speed is slowed down at the later stage so as to ensure sufficient feeding and eliminate the metallurgical defects in the ingot casting; the vacuum intermediate frequency induction furnace smelting method has the advantages that: 1. the whole process of melting, refining and alloying of the metal is carried out in a vacuum state, so that pollution caused by interaction of the same gas phase is avoided; 2. under the vacuum condition, the zirconium has strong deoxidizing capacity, other deoxidizing agents do not need to be added, and the pollution problem caused by the adoption of a metal deoxidizing agent for deoxidation is solved; 3. the vacuum induction melting furnace process can accurately control the chemical components of the alloy, can control active elements such as Al, Ti, B and the like with strong affinity with oxygen and nitrogen in a small range, and can evaporate and remove low-melting-point volatile metal impurities such as Pb, Bi, Sn, Sb and the like, thereby playing an important role in improving the performance of materials.
S3: forging the obtained ingot, wherein the forging specifically comprises the following steps,
(1) the heating temperature of the cast ingot is 935 ℃, the forging starting temperature is not lower than 850 ℃, the preheating temperature of the tool and the fixture is 310 ℃, and the final forging temperature is not lower than 650 ℃; the initial forging temperature is not lower than 850 ℃ and has the advantage that the material is easier to thermally deform when the initial forging temperature is 850 ℃ to 950 ℃, and the final forging temperature is not lower than 650 ℃ and has the advantage that the material is not easy to crack when the thermal deformation is carried out when the temperature is higher than 650 ℃;
(2) cake upsetting: discharging the heated cast ingot out of the furnace, and upsetting the cake, wherein the height of the upset cake is the design height of the forge piece, and the diameter of the upset cake is the free size;
(3) punching: punching the copper cake after cake upsetting, and punching a hole in the center of the copper cake by selecting a punch with a proper diameter to form a ring;
(4) reaming: reaming the punched ring, wherein the reaming diameter is the designed diameter of the forge piece;
(5) plane: and (5) carrying out plane treatment on the ring subjected to hole expansion, wherein the plane height is the design height of the forge piece. The forging method has the advantages that: 1. tools and equipment used for free forging are simple, the universality is good, excessive tools and dies are not required for products of multiple varieties and multiple specifications, and the cost is low; 2. compared with a cast end ring, the free forging eliminates the defects of shrinkage cavity, shrinkage porosity, air holes and the like, so that the end ring has higher mechanical property; 3. the shape is simple, and the operation is flexible;
s4: carrying out solid solution treatment on the forged end ring, controlling the solid solution temperature at 950 ℃, keeping the temperature for 1.5h, and cooling by water; carrying out aging treatment on the end ring obtained by solid solution, controlling the aging temperature at 430 ℃, keeping the temperature for 4h, and cooling in an air cooling mode; through solution and aging treatment, the alloy can be fully strengthened, and higher mechanical properties can be obtained.
S5: after rough machining is carried out on the end ring obtained through ageing treatment, most of cutting allowance is mainly removed through rough machining, surface roughness is guaranteed to meet requirements, chemical composition, mechanical property, electrical property and ultrasonic flaw detection are carried out on the end ring obtained through rough machining, finish turning is carried out on the end ring qualified in detection, milling groove machining is carried out after finish turning is carried out, the size meets the requirements of design drawings, size detection is carried out on the end ring after machining, appearance is detected and boxing is carried out after the size is qualified, boxing information is checked, a packaging box is checked, a finished end ring is obtained, and a plurality of single grooves 2 are circumferentially arranged on a groove-shaped portion 1 of the joint of the finished end ring and a guide bar at equal intervals. The groove-shaped part 1 is designed to be a single groove 2 at the joint with the conducting bar, so that the welding is convenient and the welding flux is saved.
Example 3
A preparation method for an end ring of a squirrel-cage asynchronous traction motor mainly comprises the following steps:
s1: according to the chemical compositions and weight percentages of the Cu-Cr-Zr copper alloy end ring, Cr: 1.2 percent; zr: 0.3 percent; cu: the balance, wherein the Fe content is not more than 0.08 percent, the Si content is not more than 0.1 percent, and corresponding raw materials are selected and weighed;
s2: smelting by adopting a vacuum medium-frequency induction furnace, wherein the oxygen content in the material is lower, low-melting-point impurity elements such as zinc, lead, tin and the like are volatile, the purity of the material is higher, Cu is added in an electrolytic copper plate mode during smelting, Cr and Zr are added in an intermediate alloy mode, and the vacuum degree is ensured to be lower than 5Pa in the smelting process; after all alloy elements are smelted, casting to obtain the required specification of the cast ingot, wherein the casting temperature is 1300 ℃, the casting principle is that the casting is performed at first slow and then fast and then slow, and the slow speed is performed at the later stage so as to ensure sufficient feeding and eliminate the metallurgical defects in the cast ingot; the vacuum intermediate frequency induction furnace smelting method has the advantages that: 1. the whole process of melting, refining and alloying of the metal is carried out in a vacuum state, so that pollution caused by interaction of the same gas phase is avoided; 2. under the vacuum condition, the zirconium has strong deoxidizing capacity, other deoxidizing agents do not need to be added, and the pollution problem caused by the adoption of a metal deoxidizing agent for deoxidation is solved; 3. the vacuum induction melting furnace process can accurately control the chemical components of the alloy, can control active elements such as Al, Ti, B and the like with strong affinity with oxygen and nitrogen in a small range, and can evaporate and remove low-melting-point volatile metal impurities such as Pb, Bi, Sn, Sb and the like, thereby playing an important role in improving the performance of materials.
S3: forging the obtained ingot, wherein the forging specifically comprises the following steps,
(1) the heating temperature of the cast ingot is 950 ℃, the forging starting temperature is not lower than 850 ℃, the preheating temperature of a tool and a fixture is 350 ℃, and the final forging temperature is not lower than 650 ℃; the initial forging temperature is not lower than 850 ℃ and has the advantage that the material is easier to thermally deform when the initial forging temperature is 850 ℃ to 950 ℃, and the final forging temperature is not lower than 650 ℃ and has the advantage that the material is not easy to crack when the thermal deformation is carried out when the temperature is higher than 650 ℃;
(2) cake upsetting: discharging the heated cast ingot out of the furnace, and upsetting the cake, wherein the height of the upset cake is the design height of the forge piece, and the diameter of the upset cake is the free size;
(3) punching: punching the copper cake after cake upsetting, and punching a hole in the center of the copper cake by selecting a punch with a proper diameter to form a ring;
(4) reaming: reaming the punched ring, wherein the reaming diameter is the designed diameter of the forge piece;
(5) plane: and (5) carrying out plane treatment on the ring subjected to hole expansion, wherein the plane height is the design height of the forge piece. The forging method has the advantages that: 1. tools and equipment used for free forging are simple, the universality is good, excessive tools and dies are not required for products of multiple varieties and multiple specifications, and the cost is low; 2. compared with a cast end ring, the free forging eliminates the defects of shrinkage cavity, shrinkage porosity, air holes and the like, so that the end ring has higher mechanical property; 3. the shape is simple, and the operation is flexible;
s4: carrying out solid solution treatment on the forged end ring, controlling the solid solution temperature at 980 ℃, keeping the temperature for 2h, and cooling by water; carrying out aging treatment on the end ring obtained by solid solution, wherein the aging temperature is controlled at 460 ℃, the heat preservation time is 5h, and the cooling mode adopts air cooling; through solution and aging treatment, the alloy can be fully strengthened, and higher mechanical properties can be obtained.
S5: after rough machining is carried out on the end ring obtained through ageing treatment, most of cutting allowance is mainly removed through rough machining, surface roughness is guaranteed to meet requirements, chemical composition, mechanical property, electrical property and ultrasonic flaw detection are carried out on the end ring obtained through rough machining, finish turning is carried out on the end ring qualified in detection, milling groove machining is carried out after finish turning is carried out, the size meets the requirements of design drawings, size detection is carried out on the end ring after machining, appearance is detected and boxing is carried out after the size is qualified, boxing information is checked, a packaging box is checked, a finished end ring is obtained, and a plurality of single grooves 2 are circumferentially arranged on a groove-shaped portion 1 of the joint of the finished end ring and a guide bar at equal intervals. The groove-shaped part 1 is designed to be a single groove 2 at the joint with the conducting bar, so that the welding is convenient and the welding flux is saved.
Example 4
This embodiment is substantially the same as embodiment 2 except that:
in step S2, the smelting specifically includes: 1) equally dividing an electrolytic copper plate into 2 parts, electrolyzing one part of the electrolytic copper plate, placing the electrolytic copper plate into a crucible of a vacuum intermediate frequency induction smelting furnace, vacuumizing, adding a Cr intermediate alloy into the crucible of the vacuum intermediate frequency induction smelting furnace, controlling the smelting power to be 310kW during the smelting process, reacting for 15min, preserving heat for 25min, and then casting into a Cu-Cr ingot; 2) electrolyzing the other part of the electrolytic copper plate, adding the other part of the electrolytic copper plate into a crucible of an electron beam melting furnace, vacuumizing, adding Zr intermediate alloy into the crucible of the electron beam melting furnace, ensuring that the vacuum degree is lower than 1Pa in the melting process, controlling the melting power to be 250W, the melting rate to be 21kg/h, preserving the temperature for 30min, and then casting into a Cu-Zr cast ingot; 3) carrying out electroslag remelting in an inert atmosphere by taking a Cu-Cr cast ingot as a consumable electrode, adding the Cu-Zr cast ingot into a crucible, heating until the Cu-Cr cast ingot is completely molten, slowly descending the consumable electrode into molten liquid, electrifying to start an arc, adjusting the remelting voltage to 25V and the current to 3.7kA to melt and mix the consumable electrode and the Cu-Zr, preserving the heat for 1h, and casting to obtain the required specification of the cast ingot; wherein the inert atmosphere is argon, but is not limited thereto. The Cu-Cr cast ingot is obtained by vacuum medium-frequency induction melting, the Cu-Zr cast ingot is obtained by electron beam melting, and then is subjected to mixed melting through electroslag remelting, so that the electrical property, the mechanical property and the like can be effectively improved, and the subsequently prepared end ring has higher strength, higher elongation and higher conductivity.
Example 5
This embodiment is substantially the same as embodiment 2 except that:
in step S2, the smelting specifically includes: 1) equally dividing an electrolytic copper plate into 2 parts, electrolyzing one part of the electrolytic copper plate, placing the electrolytic copper plate into a crucible of a vacuum intermediate frequency induction smelting furnace, vacuumizing, adding a Cr intermediate alloy into the crucible of the vacuum intermediate frequency induction smelting furnace, controlling the smelting power to be 330kW during the smelting process, reacting for 20min, preserving the heat for 30min, and then casting into a Cu-Cr ingot; 2) electrolyzing the other part of the electrolytic copper plate, adding the other part of the electrolytic copper plate into a crucible of an electron beam melting furnace, vacuumizing, adding Zr intermediate alloy into the crucible of the electron beam melting furnace, ensuring that the vacuum degree is lower than 1Pa in the melting process, controlling the melting power to be 250W, the melting rate to be 23kg/h, preserving the temperature for 40min, and then casting into a Cu-Zr cast ingot; 3) carrying out electroslag remelting in an inert atmosphere by taking a Cu-Cr cast ingot as a consumable electrode, adding the Cu-Zr cast ingot into a crucible, heating until the Cu-Cr cast ingot is completely molten, slowly descending the consumable electrode into molten liquid, electrifying to start an arc, adjusting remelting voltage to 35V and current to 5.3kA to melt and mix the consumable electrode and the Cu-Zr, preserving heat for 1-3h, and casting to obtain the required specification of the cast ingot; wherein the inert atmosphere is argon, but is not limited thereto. The Cu-Cr cast ingot is obtained by vacuum medium-frequency induction melting, the Cu-Zr cast ingot is obtained by electron beam melting, and then is subjected to mixed melting through electroslag remelting, so that the electrical property, the mechanical property and the like can be effectively improved, and the subsequently prepared end ring has higher strength, higher elongation and higher conductivity.
Example 6
This embodiment is substantially the same as embodiment 2 except that:
in step S2, the smelting specifically includes: 1) equally dividing an electrolytic copper plate into 2 parts, electrolyzing one part of the electrolytic copper plate, placing the electrolytic copper plate into a crucible of a vacuum intermediate frequency induction smelting furnace, vacuumizing, adding a Cr intermediate alloy into the crucible of the vacuum intermediate frequency induction smelting furnace, controlling the smelting power to be 340kW during the smelting process, reacting for 25min, preserving the heat for 35min, and then casting into a Cu-Cr ingot; 2) electrolyzing the other part of the electrolytic copper plate, adding the other part of the electrolytic copper plate into a crucible of an electron beam melting furnace, vacuumizing, adding Zr intermediate alloy into the crucible of the electron beam melting furnace, ensuring that the vacuum degree is lower than 1Pa in the melting process, controlling the melting power to be 270W, controlling the melting rate to be 24kg/h, preserving the temperature for 45min, and then casting into a Cu-Zr cast ingot; 3) carrying out electroslag remelting in an inert atmosphere by taking a Cu-Cr cast ingot as a consumable electrode, adding the Cu-Zr cast ingot into a crucible, heating until the Cu-Cr cast ingot is completely molten, slowly descending the consumable electrode into molten liquid, electrifying to start an arc, adjusting remelting voltage to 40V and current to 6.5kA to melt and mix the consumable electrode and the Cu-Zr, preserving heat for 3h, and casting to obtain the required specification of the cast ingot; wherein the inert atmosphere is argon, but is not limited thereto. The Cu-Cr cast ingot is obtained by vacuum medium-frequency induction melting, the Cu-Zr cast ingot is obtained by electron beam melting, and then is subjected to mixed melting through electroslag remelting, so that the electrical property, the mechanical property and the like can be effectively improved, and the subsequently prepared end ring has higher strength, higher elongation and higher conductivity.
Wherein, the specific performance requirements of the performance detection are as the following table 1,
table 1 end ring performance requirements (room temperature)
Demonstration of experiments
The most common material of the motor rotor end ring at present is Cu-HCP, and the main alloy elements in the material comprise the following components in percentage by mass: cu is more than or equal to 99.95 percent, Bi is less than or equal to 0.0005 percent, P: 0.002-0.007% of Pb, less than or equal to 0.005% of Pb, less than or equal to 0.03% of other impurities, typical values of tensile strength, yield strength, elongation and hardness are as follows: 200Mpa, 40Mpa, 35% and 45 HB; the groove-shaped part of the end ring of the most common motor rotor at present is designed into an annular groove at the end face of the ring, and the shape of the annular groove is shown in figure 2;
the Cu-HCP end ring has higher conductivity due to the fact that the material of the Cu-HCP end ring is pure copper, the conductivity reaches 57MS/m, but the tensile strength is about 200MPa and lower due to the fact that the pure copper material does not have a strengthening phase; on the other hand, the temperature rise of the motor rotor is high during the motor operation, which usually exceeds 200 ℃, and the strength of the material is reduced obviously when the material is used at a higher temperature. Considering the usage environment of the end ring, high conductivity and high strength are very important design parameters. Therefore, a protective ring is generally designed to be sleeved on the end ring outside the Cu-HCP end ring, so that the weight of the motor is increased, and the load of the motor is increased; and the design of the end ring and the protective ring also increases the manufacturing cost of the motor.
In addition, when the end ring is used, the end ring needs to be in braze welding connection with the guide bar, the groove-shaped part of the end ring is designed into an annular groove on the end face of the ring, more solder is needed during braze welding, and the silver solder is adopted as a common solder material, so that the cost of the motor is increased.
In examples 1 to 3, the copper alloy end ring according to the present invention was CuCrZr, and the conductivity of the copper alloy end ring was 43.5MS/m due to its low content of alloying elements, and the tensile strength of the copper alloy end ring was 380MPa due to precipitation strengthening, so that the strength of the copper alloy end ring could be greatly improved without sacrificing the conductivity thereof too much. And a protective ring is not required to be designed to be sleeved on the end ring in a hot manner, so that the conformity of the motor is reduced, and the manufacturing cost of the motor is saved.
In addition, as shown in fig. 1, the end ring of copper alloy according to the present invention has a groove-shaped portion, which is designed to be a single groove at a connection portion with the conductive bar, thereby facilitating soldering and saving solder.
Meanwhile, experimental examples 2 and 4-6 are selected to prepare Cu-Cr-Zr copper alloy end rings respectively for experimental comparison, and are sequentially recorded as experimental examples 1-4, and the results are as follows:
experimental example 2: the tensile strength is 380MPa, the yield strength is 280MPa, the elongation is 15%, the hardness is 110HB, and the electric conductivity is 43.5 MS/m;
experimental example 4: the tensile strength is 385MPa, the yield strength is 285MPa, the elongation is 13%, the hardness is 113HB, and the electric conductivity is 45.1 MS/m;
experimental example 5: the tensile strength is 395MPa, the yield strength is 290MPa, the elongation is 13%, the hardness is 120HB, and the electric conductivity is 45.5 MS/m;
experimental example 6: the tensile strength is 380MPa, the yield strength is 280MPa, the elongation is 14%, the hardness is 118HB, and the electric conductivity is 44.7 MS/m;
therefore, the effects of the experimental examples 4-6 are better than that of the experimental example 2, the tensile strength, the yield strength, the elongation, the hardness, the electric conductivity and the like are improved, and particularly, the Cu-Cr-Zr copper alloy end ring prepared in the experimental example 5 has the best performance.
Finally, it should be noted that: the above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.
Claims (5)
1. A preparation method for an end ring of a squirrel-cage asynchronous traction motor is characterized by mainly comprising the following steps:
s1: according to the chemical compositions and the weight percentages of the Cu-Cr-Zr copper alloy end ring, the chemical compositions and the weight percentages of the Cu-Cr-Zr copper alloy end ring are as follows: cr: 0.5-1.2%; zr: 0.03-0.3%; fe is less than or equal to 0.08 percent; si is less than or equal to 0.1 percent; others are less than or equal to 0.2 percent; cu: selecting and weighing corresponding raw materials for the rest;
s2: smelting the raw materials, adding the raw materials during smelting, and ensuring that the vacuum degree is lower than 5Pa during smelting; after all alloy elements are smelted, casting to obtain the required ingot casting specification;
wherein the smelting specifically comprises the following steps: 1) equally dividing an electrolytic copper plate into 2 parts, electrolyzing one part of the electrolytic copper plate, placing the electrolytic copper plate in a crucible of a vacuum intermediate frequency induction melting furnace, vacuumizing, adding a Cr intermediate alloy into the crucible of the vacuum intermediate frequency induction melting furnace, ensuring that the vacuum degree is lower than 5Pa in the melting process, controlling the melting power to be 310 and 340kW, reacting for 15-25min, preserving the heat for 25-35min, and then casting into a Cu-Cr ingot; 2) electrolyzing the other part of the electrolytic copper plate, adding the other part of the electrolytic copper plate into a crucible of an electron beam melting furnace, vacuumizing, adding Zr intermediate alloy into the crucible of the electron beam melting furnace, ensuring that the vacuum degree is lower than 1Pa in the melting process, controlling the melting power to be 250-270W, keeping the melting rate to be 21-24kg/h, preserving the temperature for 30-45min, and then casting into a Cu-Zr cast ingot; 3) carrying out electroslag remelting in an inert atmosphere by taking a Cu-Cr cast ingot as a consumable electrode, adding Cu-Zr into a crucible, heating until the Cu-Zr is completely molten, slowly lowering the consumable electrode into molten liquid, electrifying to start an arc, adjusting remelting voltage to 25-40V and current to 3.7-6.5kA, melting and mixing the consumable electrode and the Cu-Zr, preserving heat for 1-3h, and casting to obtain the required cast ingot specification; wherein the inert atmosphere is argon;
s3: forging the obtained cast ingot, wherein the forging comprises heating, cake upsetting, punching, hole expanding and plane surface;
s4: carrying out solid solution treatment on the end ring obtained by forging, controlling the solid solution temperature to be 950 +/-30 ℃, keeping the temperature for 1-2h, and cooling by water; carrying out aging treatment on the end ring obtained by solid solution, controlling the aging temperature to be 430 +/-30 ℃, keeping the temperature for 3-5h, and cooling by air;
s5: and after rough machining is carried out on the end ring obtained by aging treatment, performance detection, mechanical machining and finished product detection are carried out in sequence to obtain the finished end ring, and a plurality of single grooves (2) are circumferentially arranged on a groove-shaped part (1) at the joint of the finished end ring and the guide bar at equal intervals.
2. The method for preparing an end ring for a squirrel-cage asynchronous traction motor according to claim 1, characterized in that said forging comprises in particular the steps of:
(1) the heating temperature of the cast ingot is 900-950 ℃, the starting forging temperature is not lower than 850 ℃, the preheating temperature of the tool and the clamp is 250-350 ℃, and the final forging temperature is not lower than 650 ℃;
(2) cake upsetting: discharging the heated cast ingot out of the furnace, and upsetting the cake, wherein the height of the upset cake is the design height of the forge piece, and the diameter of the upset cake is the free size;
(3) punching: punching the copper cake after cake upsetting, and punching a hole in the center of the copper cake by selecting a punch with a proper diameter to form a ring;
(4) reaming: reaming the punched ring, wherein the reaming diameter is the designed diameter of the forge piece;
(5) plane: and (5) carrying out plane treatment on the ring subjected to hole expansion, wherein the plane height is the design height of the forge piece.
3. The method for preparing the squirrel-cage asynchronous traction motor end ring according to claim 1, wherein the performance detection is specifically as follows: and (4) detecting chemical components, mechanical properties, electrical properties and ultrasonic flaw detection of the end ring obtained by rough machining.
4. The method for preparing the end ring of the squirrel-cage asynchronous traction motor according to claim 1, wherein the machining is specifically as follows: and (4) finish turning the end ring qualified for detection, and then performing milling groove machining, wherein the size meets the requirement of a design drawing.
5. The method for preparing the squirrel-cage asynchronous traction motor end ring according to claim 1, wherein the finished product detection is specifically as follows: and (3) carrying out size detection on the machined end ring, detecting the appearance and boxing the end ring after the end ring is qualified in size, checking boxing information and checking the packaging box.
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| CN111621665A (en) * | 2020-06-16 | 2020-09-04 | 西安斯瑞先进铜合金科技有限公司 | Preparation method of copper-zirconium end ring material for train asynchronous motor |
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