CN116926284A - Processing technology of high-precision gear - Google Patents

Processing technology of high-precision gear Download PDF

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Publication number
CN116926284A
CN116926284A CN202310824557.6A CN202310824557A CN116926284A CN 116926284 A CN116926284 A CN 116926284A CN 202310824557 A CN202310824557 A CN 202310824557A CN 116926284 A CN116926284 A CN 116926284A
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China
Prior art keywords
tooth
treatment
blank
cold extrusion
die
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CN202310824557.6A
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Chinese (zh)
Inventor
张春宾
赵俊平
李少兵
吴永强
戴勇
王祖勇
樊晓光
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Dongfeng Trucks Co ltd
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Dongfeng Trucks Co ltd
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Priority to CN202310824557.6A priority Critical patent/CN116926284A/en
Publication of CN116926284A publication Critical patent/CN116926284A/en
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C21D1/32—Soft annealing, e.g. spheroidising
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00—Extruding metal; Impact extrusion
    • B21C23/002—Extruding materials of special alloys so far as the composition of the alloy requires or permits special extruding methods of sequences
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
    • B21C23/00—Extruding metal; Impact extrusion
    • B21C23/02—Making uncoated products
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C21D1/30—Stress-relieving
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/32—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for gear wheels, worm wheels, or the like
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C8/00—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C8/06—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases
    • C23C8/08—Solid state diffusion of only non-metal elements into metallic material surfaces; Chemical surface treatment of metallic material by reaction of the surface with a reactive gas, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using gases only one element being applied
    • C23C8/20—Carburising

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Thermal Sciences (AREA)
  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Child & Adolescent Psychology (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Forging (AREA)

Abstract

The application relates to a processing technology of a high-precision gear, which comprises the following steps: spheroidizing annealing treatment is carried out on the tooth blank so as to reduce the hardness of the tooth blank below a first hardness threshold value; after the spheroidizing annealing treatment is finished, carrying out cold extrusion treatment on the tooth blank so as to form a tooth shape of the tooth blank, wherein the tooth surface of the tooth blank with the tooth shape has a tooth surface design allowance; after the cold extrusion treatment is finished, carrying out stress relief annealing treatment on the tooth blank; and after the stress relief annealing treatment is finished, performing precise cold extrusion treatment on the tooth blank to obtain the high-precision gear, wherein the extrusion amount of the tooth surface in the precise cold extrusion treatment is equal to the design allowance of the tooth surface. The application is a cold extrusion treatment procedure for the first time, extrudes to obtain a blank with tooth shape, and leaves a tooth surface allowance which is the extrusion amount for the second time. The method improves the precision of the part by extruding the tooth surface twice, and the precision of the final part can meet the production requirement.

Description

Processing technology of high-precision gear
Technical Field
The application relates to the technical field of automobile part manufacturing, in particular to a processing technology of a high-precision gear.
Background
At present, the domestic straight gear cold extrusion process has been widely applied, and the main process is as follows: blank-warm forging-cold extrusion-carburizing and quenching-grinding teeth, the tooth form precision of the part after cold extrusion is usually 8.5 grade, and the tooth direction precision is usually 9 grade. The gear tooth form precision and the gear tooth direction precision after cold extrusion are low, and in addition, the tooth form precision and the gear tooth direction precision after carburizing and quenching are reduced by at least 1 grade due to the existence of internal stress.
In the aspect of precision cold extrusion, a paper describes that warm forging preforming and cold finishing are adopted, preformed parts are provided with finishing tooth form allowance, the gear precision is improved through cold finishing, and the gear direction precision can reach 8 stages.
However, the precision of the loading part is at least 7 levels, so that the gear precision is improved by carrying out finish machining on the tooth surface, for example, a planetary straight gear is additionally provided with a gear grinding process, an inner gear ring is additionally provided with a precision inserting rolling process, and the production cost is greatly increased.
Disclosure of Invention
The embodiment of the application provides a processing technology of a high-precision gear, and the precision of the gear manufactured by the processing technology after heat treatment can meet the production requirement, so that the processing technology can cancel the tooth surface finish machining procedure, and achieve the purpose of reducing the cost.
The embodiment of the application provides a processing technology of a high-precision gear, which comprises the following steps of:
spheroidizing annealing treatment is carried out on the tooth blank so that the hardness of the tooth blank is reduced below a first hardness threshold value;
after the spheroidizing annealing treatment is finished, carrying out cold extrusion treatment on the tooth blank so as to enable the tooth blank to form a tooth shape, wherein the tooth surface of the tooth blank with the tooth shape is provided with a tooth surface design allowance;
after the cold extrusion treatment is finished, carrying out stress relief annealing treatment on the tooth blank so as to reduce the hardness of the tooth blank below a second hardness threshold value;
after the stress relief annealing treatment is finished, performing precise cold extrusion treatment on the tooth blank to obtain a high-precision gear;
wherein the extrusion amount of the tooth surface in the precision cold extrusion treatment is equal to the tooth surface design allowance.
In some embodiments, the spheroidizing annealing process comprises: preserving heat for 10-12 h at 750-770 ℃, then cooling to 670-690 ℃ and preserving heat for 22-26 h, and then cooling with a furnace.
In some embodiments, the stress relief annealing process comprises: heat preservation is carried out for 7 to 9 hours at 790 to 810 ℃, then the temperature is reduced to 720 to 740 ℃ for 1 to 3 hours, then the temperature is reduced to 670 to 690 ℃ for 1 to 3 hours, then the temperature is reduced to 530 to 550 ℃ for 4 to 5 hours, and then the furnace is cooled.
In some embodiments, the cold extrusion process comprises: the die-in temperature of the tooth blank is 75-85 ℃, the working temperature of the die is 180-220 ℃, the die-out temperature of the tooth blank is 220-260 ℃, and the size of the die is obtained based on the single side of the tooth surface allowance, the die-out temperature and the linear expansion coefficient corresponding to the die-out temperature.
In some embodiments, the precision cold extrusion process comprises: the die-in temperature of the tooth blank is 95-105 ℃, the working temperature of the die is 105-125 ℃, the die-out temperature of the tooth blank is 115-135 ℃, and the size of the die is obtained based on the single side of the tooth surface allowance, the die-out temperature and the linear expansion coefficient corresponding to the die-out temperature.
In some embodiments, the first hardness threshold is 145HB;
and/or the second hardness threshold is 135HB.
In some embodiments, the process further comprises, prior to spheroidizing annealing the tooth blank: sawing the bar stock to a specified size, heating and then finishing upsetting and punching on forging equipment.
In some embodiments, after the spheroidizing annealing process is completed and before the cold extrusion process is performed on the tooth blank, the processing process further includes: shot blasting and polymer lubrication are sequentially performed.
In some embodiments, after the stress relief annealing process is completed and before the precision cold extrusion process is performed on the tooth blank, the process further comprises: and (5) high polymer lubrication treatment.
In some embodiments, after the tooth blank is subjected to the precision cold extrusion treatment, the processing technology further includes: carburizing and quenching treatment.
The technical scheme provided by the application has the beneficial effects that:
in the processing technology of the high-precision gear provided by the embodiment of the application, the tooth blank is subjected to spheroidizing annealing treatment so as to reduce the hardness of the tooth blank to a certain hardness value, thereby facilitating the subsequent cold extrusion treatment, wherein in the cold extrusion treatment process, a die for cold extrusion treatment can be designed in advance based on the shape, the size and the like of the high-precision gear to be obtained, the die is provided with a tooth surface design allowance, and after cold extrusion treatment, the tooth blank is provided with a tooth shape, the tooth surface of the tooth blank with the tooth shape is provided with the tooth surface design allowance, and the tooth surface design allowance is the tooth surface extrusion amount in the next precision cold extrusion treatment process. After cold extrusion treatment, stress relief annealing treatment is carried out to reduce the thermal stress of the tooth blank. Then, the precise cold extrusion treatment is carried out, the extrusion amount of the tooth surface is equal to the design allowance of the tooth surface in the cold extrusion treatment procedure, and finally, the carburizing and quenching treatment is carried out, thus obtaining the high-precision gear.
In the application, the first time is the cold extrusion treatment procedure, the blank with tooth shape is extruded, the first time die leaves the tooth surface allowance, and the allowance is the extrusion amount of the second time precise cold extrusion treatment. That is, the precision of the part is improved by extruding the tooth surface twice, and the precision of the final part can meet the production requirement, so that the tooth surface finish machining process can be omitted by adopting the high-precision gear machining process provided by the application, and the aim of reducing the cost is fulfilled.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for the description of the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a flow chart of a processing process of a high-precision gear according to an embodiment of the present application.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present application more apparent, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application, and it is apparent that the described embodiments are some embodiments of the present application, but not all embodiments of the present application. All other embodiments, which can be made by those skilled in the art based on the embodiments of the application without making any inventive effort, are intended to be within the scope of the application.
The embodiment of the application provides a processing technology of a high-precision gear, and the precision of the gear manufactured by the processing technology after heat treatment can meet the production requirement, so that the processing technology can cancel the tooth surface finish machining procedure, and achieve the purpose of reducing the cost.
Referring to fig. 1, an embodiment of the present application provides a processing technology of a high-precision gear, including the steps of:
101: the bar is sawn to a specified size, then heated, and then upset punching is completed on the forging equipment.
102: under the protection atmosphere, performing spheroidizing annealing treatment on the tooth blank so as to reduce the hardness of the tooth blank to be below a first hardness threshold value; the first hardness threshold may be determined according to actual process requirements, e.g., as an example, the first hardness threshold may be selected from 140HB to 145HB, e.g., the first hardness threshold is 145HB. Too high hardness can lead to too large extrusion force, affect die life, and also can lead to poor part accuracy after extrusion.
Specifically, the spheroidizing annealing treatment includes: preserving heat for 10-12 h at 750-770 ℃, then reducing to 670-690 ℃ and preserving heat for 22-26 h, and then cooling with a furnace, wherein the hardness can be reduced to 140HB, and the grains are equiaxed.
103: and (3) performing shot blasting on the tooth blank subjected to spheroidizing annealing, and after finishing the shot blasting, continuing to perform necessary machining and then performing polymer lubrication.
The above-mentioned necessary working includes, in particular, turning of the tube blank.
104: after the polymer lubrication treatment is completed, cold extrusion treatment is carried out on the tooth blank on a press machine so as to form the tooth shape of the tooth blank.
In step 104, the cold extrusion process is followed by a tooth blank having not only a tooth form, but also a tooth surface of the tooth blank having a tooth surface design margin.
The design allowance of the tooth surface is reserved for the next cold extrusion, namely the tooth blank with the tooth shape after the cold extrusion treatment, and the tooth surface is reserved for the next cold extrusion.
105: and after the cold extrusion treatment is finished, carrying out stress relief annealing treatment on the tooth blank in a protective atmosphere so as to enable the hardness of the tooth blank to be reduced below a second hardness threshold value, and after the stress relief annealing treatment is finished, continuing to carry out necessary processing and then carrying out polymer lubrication treatment.
Specifically, the stress relief annealing treatment includes: heat preservation is carried out for 7 to 9 hours at 790 to 810 ℃, then the temperature is reduced to 720 to 740 ℃ for 1 to 3 hours, then the temperature is reduced to 670 to 690 ℃ for 1 to 3 hours, then the temperature is reduced to 530 to 550 ℃ for 4 to 5 hours, and then the furnace is cooled.
The second hardness threshold is less than the first hardness threshold, and the second hardness threshold may be determined according to actual process requirements, for example, the second hardness threshold may be selected from 130HB to 135HB, such as the second hardness threshold being 135HB, as an example.
After stress relief annealing treatment, the hardness can be reduced to below 135HB, the grains are equiaxed, and the grains at the deformed part are finer.
The stress relief annealing is performed on the basis of spheroidizing annealing and cold extrusion, so that the annealing temperature is set to 790-810 ℃, the structure is more refined, the heat preservation at 720-740 ℃ is the highest temperature after the structure is transformed, the structure stress is reduced, and the heat preservation at 530-550 ℃ is the heat stress reduction.
The necessary processing before the polymer lubrication treatment can comprise finish machining of the upper end face, the lower end face and the outer circle so as to ensure the roundness and the coaxiality of the outer circle and ensure the flatness and the perpendicularity of the two end faces.
For the stress relief annealing, the residual stress can be measured, an X-ray diffraction method is generally adopted to measure the residual stress on the tooth surface of the stress relief annealed part, the measured stress value is within a certain range interval, and the stress relief annealing of the part is considered to be qualified. The range can be determined according to the actual part index requirements, for example, in the range of-20-20 Mpa, and the stress can be considered to be removed.
106: and after the stress relief annealing treatment is finished, performing precise cold extrusion treatment on the tooth blank.
In step 106, the extrusion amount of the tooth surface in the precision cold extrusion process is equal to the design margin of the tooth surface.
107: and after the precision cold extrusion treatment is finished, carburizing and quenching treatment is carried out, so that the high-precision gear is obtained.
Wherein, the carburizing and quenching treatment is to put the parts into a multipurpose furnace for carburizing treatment, put the parts into the multipurpose furnace, heat up to 920-940 ℃, keep the temperature for 180 minutes, and carry out the carburizing treatment. After the furnace is cooled to 830-850 ℃, the parts are placed in quenching oil with the temperature of 110-130 ℃ for quenching for 40 minutes. The effective hardening layer depth of the part is 0.7-1.0mm, the carbide grade is less than or equal to 5, the residual austenite grade is less than or equal to 5, the surface hardness is HRC58-63, and the core hardness is HRC30-38, so that the carburized and quenched part is qualified.
In the processing technology of the high-precision gear provided by the embodiment of the application, the tooth blank is subjected to spheroidizing annealing treatment so as to reduce the hardness of the tooth blank to a certain hardness value, thereby facilitating the subsequent cold extrusion treatment, wherein in the cold extrusion treatment process, a die for cold extrusion treatment can be designed in advance based on the shape, the size and the like of the high-precision gear to be obtained, the die is provided with a tooth surface design allowance, and after cold extrusion treatment, the tooth blank is provided with a tooth shape, the tooth surface of the tooth blank with the tooth shape is provided with the tooth surface design allowance, and the tooth surface design allowance is the tooth surface extrusion amount in the next precision cold extrusion treatment process. After cold extrusion treatment, stress relief annealing treatment is carried out to reduce the thermal stress of the tooth blank. Then, the precise cold extrusion treatment is carried out, the extrusion amount of the tooth surface is equal to the design allowance of the tooth surface in the cold extrusion treatment procedure, and finally, the carburizing and quenching treatment is carried out, thus obtaining the high-precision gear.
In the application, the first time is the cold extrusion treatment procedure, the blank with tooth shape is extruded, the first time die leaves the tooth surface allowance, and the allowance is the extrusion amount of the second time precise cold extrusion treatment. That is, the precision of the part is improved by extruding the tooth surface twice, and the precision of the final part can meet the production requirement, so that the tooth surface finish machining process can be omitted by adopting the high-precision gear machining process provided by the application, and the aim of reducing the cost is fulfilled.
The applicant has shown from a number of experimental studies that the extrusion is preferably controlled between 0.15 and 0.25 mm. If the extrusion amount is less than 0.15mm, the plastic deformation of the gear is too small, even the extrusion amount is too small, the part only elastically deforms, the extruded part elastically returns, and the accuracy of the extruded gear cannot reach the expected effect. If the extrusion amount exceeds 0.25mm, the parts undergo severe plastic deformation, and at the moment, the precision of the parts can be reduced along with the increase of the extrusion amount, and the precision of the final gear cannot reach the expectations.
In the step 104, the cold extrusion process includes: the die entering temperature of the tooth blank is 75-85 ℃, the working temperature of the die is 180-220 ℃, and the die stripping temperature of the tooth blank is 220-260 ℃, wherein the die used for cold extrusion treatment can be designed in advance, and specifically, the size of the die can be obtained based on the shape and the size of the high-precision gear to be manufactured, the tooth surface allowance unilateral, the die stripping temperature and the linear expansion coefficient corresponding to the die stripping temperature. That is, the size of the die used for the cold extrusion process is reversely pushed out by the shape and size of the high-precision gear to be manufactured, the single side of the tooth surface margin, the die-out temperature, and the linear expansion coefficient corresponding to the die-out temperature.
In the step 106, the precision cold extrusion process includes: the die entering temperature of the tooth blank is 95-105 ℃, the working temperature of the die is 105-125 ℃, and the die stripping temperature of the tooth blank is 115-135 ℃, wherein the die used for the precise cold extrusion treatment can be designed in advance, and specifically, the size of the die is obtained based on the shape and the size of the high-precision gear to be manufactured, the tooth surface allowance unilateral, the die stripping temperature and the linear expansion coefficient corresponding to the die stripping temperature. That is, the size of the die used for the precision cold extrusion process is inversely pushed out by the shape and size of the high-precision gear to be manufactured, the single side of the tooth surface margin, the die-out temperature, and the linear expansion coefficient corresponding to the die-out temperature.
Example 1:
example 1 provides a transmission planetary spur gear of 20CrMnTi.
The processing technology of the planetary straight gear of the gearbox comprises the following steps:
101: the bar is sawn to a specified size, then heated, and then upset punching is completed on the forging equipment.
102: and (3) carrying out spheroidizing annealing treatment on the tooth blank in a protective atmosphere so as to reduce the hardness of the tooth blank to 140-145 HB.
Specifically, the spheroidizing annealing treatment includes: heat preservation is carried out for 10 hours at 760 ℃, then heat preservation is carried out for 24 hours after the temperature is reduced to 680 ℃, and then furnace cooling is carried out, at this time, the hardness can be reduced to 140-145 HB, and the grains are equiaxed.
103: and (3) performing shot blasting on the tooth blank subjected to spheroidizing annealing, and after finishing the shot blasting, continuing to perform necessary machining and then performing polymer lubrication.
The above-mentioned necessary working includes, in particular, turning of the tube blank.
104: after the polymer lubrication treatment is finished, cold extrusion treatment is carried out on the tooth blank on a press machine, so that the tooth blank forms tooth shape, and the precision of the gear after cold extrusion can reach 7.5 grade.
In step 104, the cold extrusion process is followed by a tooth blank having not only a tooth form, but also a tooth surface of the tooth blank having a tooth surface design margin.
The design allowance of the tooth surface is reserved for the next cold extrusion, namely the tooth blank with the tooth shape after the cold extrusion treatment, and the tooth surface is reserved for the next cold extrusion.
In the step 104, the cold extrusion process includes: the die entering temperature of the tooth blank is kept at 80+/-5 ℃, the working temperature of the die is kept at 200+/-5 ℃, the die stripping temperature of the tooth blank is kept at 230+/-5 ℃, the design allowance of the tooth surface, namely the single side of the tooth surface allowance is 0.15mm, and the size of the die is designed according to the linear expansion coefficient of the tooth blank at 230 ℃ and the design allowance of the tooth surface.
105: and after the cold extrusion treatment is finished, carrying out stress relief annealing treatment on the tooth blank under a protective atmosphere, and after the stress relief annealing treatment is finished, continuing to carry out necessary processing and then carrying out macromolecule lubrication treatment.
Specifically, the stress relief annealing treatment includes: preserving heat at 800 ℃ for 8 hours, then cooling to 730 ℃ for 2 hours, then cooling to 680 ℃ for 2 hours, then cooling to 530 ℃ for 4 hours, and then cooling with a furnace. At this time, the hardness can be reduced to below 135HB, and the grains at the deformation part are more refined.
The destressing annealing is performed on the basis of spheroidizing annealing and cold extrusion, so that the annealing temperature of 800 ℃ is set, the structure is further refined, the purpose of 730 ℃ heat preservation is to preserve heat at the highest temperature after the structure is transformed, the structure stress is reduced, and the purpose of 530 ℃ heat preservation is to reduce the thermal stress.
The necessary processing before the polymer lubrication treatment can comprise finish machining of the upper end face, the lower end face and the outer circle so as to ensure the roundness and the coaxiality of the outer circle and ensure the flatness and the perpendicularity of the two end faces.
106: after the stress relief annealing treatment is completed, the gear blank is subjected to precise cold extrusion treatment, and the gear precision after the precise cold extrusion can reach 6 levels.
In step 106, the extrusion amount of the tooth surface in the precision cold extrusion process is equal to the design margin of the tooth surface.
In the step 106, the precision cold extrusion process includes: the die-in temperature of the tooth blank is kept at 100+/-5 ℃, the working temperature of the die is kept at 110+/-5 ℃, the die-out temperature of the tooth blank is kept at 120+/-5 ℃, and the die size is designed according to the linear expansion coefficient of the tooth blank at 120 ℃ and the design allowance of the tooth surface.
107: after the precision cold extrusion treatment is finished, carburizing and quenching treatment is carried out, so that the high-precision gear is obtained, the gear precision is 6-6.5, and the product use requirement is met.
Example 2:
example 2 provides a transmission annulus gear of material 20MnCr5.
The processing technology of the internal gear of the gearbox comprises the following steps:
101: the bar is sawn to a specified size, then heated, and then upset punching is completed on the forging equipment.
102: and (3) carrying out spheroidizing annealing treatment on the tooth blank in a protective atmosphere so as to reduce the hardness of the tooth blank to 140-145 HB.
Specifically, the spheroidizing annealing treatment includes: heat preservation is carried out for 10 hours at 760 ℃, then heat preservation is carried out for 24 hours after the temperature is reduced to 680 ℃, and then furnace cooling is carried out, at this time, the hardness can be reduced to 140-145 HB, and the grains are equiaxed.
103: and (3) performing shot blasting on the tooth blank subjected to spheroidizing annealing, and after finishing the shot blasting, continuing to perform necessary machining and then performing polymer lubrication.
The above-mentioned necessary working includes, in particular, turning of the tube blank.
104: after the polymer lubrication treatment is finished, cold extrusion treatment is carried out on the tooth blank on a press machine, so that the tooth blank forms tooth shape, and the precision of the gear after cold extrusion can reach 7.5 grade.
In step 104, the cold extrusion process is followed by a tooth blank having not only a tooth form, but also a tooth surface of the tooth blank having a tooth surface design margin.
The design allowance of the tooth surface is reserved for the next cold extrusion, namely the tooth blank with the tooth shape after the cold extrusion treatment, and the tooth surface is reserved for the next cold extrusion.
In the step 104, the cold extrusion process includes: the die entering temperature of the tooth blank is kept at 80+/-5 ℃, the working temperature of the die is kept at 215+/-5 ℃, the die stripping temperature of the tooth blank is kept at 250+/-5 ℃, the tooth surface design allowance, namely the single side of the tooth surface allowance is 0.2mm, and the die size is designed according to the linear expansion coefficient of the tooth blank at 250 ℃ and the tooth surface design allowance.
105: and after the cold extrusion treatment is finished, carrying out stress relief annealing treatment on the tooth blank under a protective atmosphere, and after the stress relief annealing treatment is finished, continuing to carry out necessary processing and then carrying out macromolecule lubrication treatment.
Specifically, the stress relief annealing treatment includes: preserving heat at 800 ℃ for 8 hours, then cooling to 730 ℃ for 2 hours, then cooling to 680 ℃ for 2 hours, then cooling to 530 ℃ for 4 hours, and then cooling with a furnace. At this time, the hardness can be reduced to below 135HB, and the grains at the deformation part are more refined.
The destressing annealing is performed on the basis of spheroidizing annealing and cold extrusion, so that the annealing temperature of 800 ℃ is set, the structure is further refined, the purpose of 730 ℃ heat preservation is to preserve heat at the highest temperature after the structure is transformed, the structure stress is reduced, and the purpose of 530 ℃ heat preservation is to reduce the thermal stress.
The necessary processing before the polymer lubrication treatment can comprise finish machining of the upper end face, the lower end face and the outer circle so as to ensure the roundness and the coaxiality of the outer circle and ensure the flatness and the perpendicularity of the two end faces.
106: after the stress relief annealing treatment is completed, the gear blank is subjected to precise cold extrusion treatment, and the gear precision after the precise cold extrusion can reach 6-6.5 levels.
In step 106, the extrusion amount of the tooth surface in the precision cold extrusion process is equal to the design margin of the tooth surface.
In the step 106, the precision cold extrusion process includes: the die-in temperature of the tooth blank is kept at 100+/-5 ℃, the working temperature of the die is kept at 110+/-5 ℃, the die-out temperature of the tooth blank is kept at 120+/-5 ℃, and the die size is designed according to the linear expansion coefficient of the tooth blank at 120 ℃ and the design allowance of the tooth surface.
107: after the precision cold extrusion treatment is completed, carburizing and quenching treatment is carried out, so that the high-precision gear is obtained, the gear precision is 6.5 grade, and the product use requirement is met.
Example 3:
example 3 provides a gearbox sun gear of material 20CrMnTi.
The processing technology of the gearbox sun gear comprises the following steps:
101: the bar is sawn to a specified size, then heated, and then upset punching is completed on the forging equipment.
102: and (3) carrying out spheroidizing annealing treatment on the tooth blank in a protective atmosphere so as to reduce the hardness of the tooth blank to 140-145 HB.
Specifically, the spheroidizing annealing treatment includes: heat preservation is carried out for 10 hours at 760 ℃, then heat preservation is carried out for 24 hours after the temperature is reduced to 680 ℃, and then furnace cooling is carried out, at this time, the hardness can be reduced to 140-145 HB, and the grains are equiaxed.
103: and (3) performing shot blasting on the tooth blank subjected to spheroidizing annealing, and after finishing the shot blasting, continuing to perform necessary machining and then performing polymer lubrication.
The above-mentioned necessary working includes, in particular, turning of the tube blank.
104: after the polymer lubrication treatment is finished, cold extrusion treatment is carried out on the tooth blank on a press machine, so that the tooth blank forms tooth shape, and the precision of the gear after cold extrusion can reach 7.5 grade.
In step 104, the cold extrusion process is followed by a tooth blank having not only a tooth form, but also a tooth surface of the tooth blank having a tooth surface design margin.
The design allowance of the tooth surface is reserved for the next cold extrusion, namely the tooth blank with the tooth shape after the cold extrusion treatment, and the tooth surface is reserved for the next cold extrusion.
In the step 104, the cold extrusion process includes: the die entering temperature of the tooth blank is kept at 80+/-5 ℃, the working temperature of the die is kept at 200+/-5 ℃, the die stripping temperature of the tooth blank is kept at 230+/-5 ℃, the design allowance of the tooth surface, namely the single side of the tooth surface allowance is 0.18mm, and the size of the die is designed according to the linear expansion coefficient of the tooth blank at 230 ℃ and the design allowance of the tooth surface.
105: and after the cold extrusion treatment is finished, carrying out stress relief annealing treatment on the tooth blank under a protective atmosphere, and after the stress relief annealing treatment is finished, continuing to carry out necessary processing and then carrying out macromolecule lubrication treatment.
Specifically, the stress relief annealing treatment includes: preserving heat at 800 ℃ for 8 hours, then cooling to 730 ℃ for 2 hours, then cooling to 680 ℃ for 2 hours, then cooling to 530 ℃ for 4 hours, and then cooling with a furnace. At this time, the hardness can be reduced to below 135HB, and the grains at the deformation part are more refined.
The destressing annealing is performed on the basis of spheroidizing annealing and cold extrusion, so that the annealing temperature of 800 ℃ is set, the structure is further refined, the purpose of 730 ℃ heat preservation is to preserve heat at the highest temperature after the structure is transformed, the structure stress is reduced, and the purpose of 530 ℃ heat preservation is to reduce the thermal stress.
The necessary processing before the polymer lubrication treatment can comprise finish machining of the upper end face, the lower end face and the outer circle so as to ensure the roundness and the coaxiality of the outer circle and ensure the flatness and the perpendicularity of the two end faces.
106: after the stress relief annealing treatment is completed, the gear blank is subjected to precise cold extrusion treatment, and the gear precision after the precise cold extrusion can reach 6 levels.
In step 106, the extrusion amount of the tooth surface in the precision cold extrusion process is equal to the design margin of the tooth surface.
In the step 106, the precision cold extrusion process includes: the die-in temperature of the tooth blank is kept at 100+/-5 ℃, the working temperature of the die is kept at 110+/-5 ℃, the die-out temperature of the tooth blank is kept at 125+/-5 ℃, and the die size is designed according to the linear expansion coefficient of the tooth blank at 125 ℃ and the design allowance of the tooth surface.
107: after the precision cold extrusion treatment is finished, carburizing and quenching treatment is carried out, so that the high-precision gear is obtained, the gear precision is 6-6.5, and the product use requirement is met.
Example 4:
example 4 provides a transmission annulus gear of material 20MnCr5.
The processing technology of the internal gear of the gearbox comprises the following steps:
101: the bar is sawn to a specified size, then heated, and then upset punching is completed on the forging equipment.
102: and (3) carrying out spheroidizing annealing treatment on the tooth blank in a protective atmosphere so as to reduce the hardness of the tooth blank to 140-145 HB.
Specifically, the spheroidizing annealing treatment includes: heat preservation is carried out for 10 hours at 760 ℃, then heat preservation is carried out for 24 hours after the temperature is reduced to 680 ℃, and then furnace cooling is carried out, at this time, the hardness can be reduced to 140-145 HB, and the grains are equiaxed.
103: and (3) performing shot blasting on the tooth blank subjected to spheroidizing annealing, and after finishing the shot blasting, continuing to perform necessary machining and then performing polymer lubrication.
The above-mentioned necessary working includes, in particular, turning of the tube blank.
104: after the polymer lubrication treatment is finished, cold extrusion treatment is carried out on the tooth blank on a press machine, so that the tooth blank forms tooth shape, and the precision of the gear after cold extrusion can reach 7.5 grade.
In step 104, the cold extrusion process is followed by a tooth blank having not only a tooth form, but also a tooth surface of the tooth blank having a tooth surface design margin.
The design allowance of the tooth surface is reserved for the next cold extrusion, namely the tooth blank with the tooth shape after the cold extrusion treatment, and the tooth surface is reserved for the next cold extrusion.
In the step 104, the cold extrusion process includes: the die entering temperature of the tooth blank is kept at 80+/-5 ℃, the working temperature of the die is kept at 215+/-5 ℃, the die stripping temperature of the tooth blank is kept at 250+/-5 ℃, the tooth surface design allowance, namely the single side of the tooth surface allowance is 0.1mm, and the die size is designed according to the linear expansion coefficient of the tooth blank at 250 ℃ and the tooth surface design allowance.
105: and after the cold extrusion treatment is finished, carrying out stress relief annealing treatment on the tooth blank under a protective atmosphere, and after the stress relief annealing treatment is finished, continuing to carry out necessary processing and then carrying out macromolecule lubrication treatment.
Specifically, the stress relief annealing treatment includes: preserving heat at 800 ℃ for 8 hours, then cooling to 730 ℃ for 2 hours, then cooling to 680 ℃ for 2 hours, then cooling to 530 ℃ for 4 hours, and then cooling with a furnace. At this time, the hardness can be reduced to below 135HB, and the grains at the deformation part are more refined.
The destressing annealing is performed on the basis of spheroidizing annealing and cold extrusion, so that the annealing temperature of 800 ℃ is set, the structure is further refined, the purpose of 730 ℃ heat preservation is to preserve heat at the highest temperature after the structure is transformed, the structure stress is reduced, and the purpose of 530 ℃ heat preservation is to reduce the thermal stress.
The necessary processing before the polymer lubrication treatment can comprise finish machining of the upper end face, the lower end face and the outer circle so as to ensure the roundness and the coaxiality of the outer circle and ensure the flatness and the perpendicularity of the two end faces.
106: after the stress relief annealing treatment is completed, the gear blank is subjected to precise cold extrusion treatment, and the gear precision after the precise cold extrusion can reach 6.5 levels.
In step 106, the extrusion amount of the tooth surface in the precision cold extrusion process is equal to the design margin of the tooth surface.
In the step 106, the precision cold extrusion process includes: the die-in temperature of the tooth blank is kept at 100+/-5 ℃, the working temperature of the die is kept at 110+/-5 ℃, the die-out temperature of the tooth blank is kept at 125+/-5 ℃, and the die size is designed according to the linear expansion coefficient of the tooth blank at 125 ℃ and the design allowance of the tooth surface.
107: after the precision cold extrusion treatment is completed, carburizing and quenching treatment is carried out, so that the high-precision gear is obtained, the gear precision is 7.0 grade, and the use requirement of the product is not met.
Example 5:
example 5 provides a transmission annulus gear of material 20MnCr5.
The processing technology of the internal gear of the gearbox comprises the following steps:
101: the bar is sawn to a specified size, then heated, and then upset punching is completed on the forging equipment.
102: and (3) carrying out spheroidizing annealing treatment on the tooth blank in a protective atmosphere so as to reduce the hardness of the tooth blank to 140-145 HB.
Specifically, the spheroidizing annealing treatment includes: heat preservation is carried out for 10 hours at 760 ℃, then heat preservation is carried out for 24 hours after the temperature is reduced to 680 ℃, and then furnace cooling is carried out, at this time, the hardness can be reduced to 140-145 HB, and the grains are equiaxed.
103: and (3) performing shot blasting on the tooth blank subjected to spheroidizing annealing, and after finishing the shot blasting, continuing to perform necessary machining and then performing polymer lubrication.
The above-mentioned necessary working includes, in particular, turning of the tube blank.
104: after the polymer lubrication treatment is finished, cold extrusion treatment is carried out on the tooth blank on a press machine, so that the tooth blank forms tooth shape, and the precision of the gear after cold extrusion can reach 7.5 grade.
In step 104, the cold extrusion process is followed by a tooth blank having not only a tooth form, but also a tooth surface of the tooth blank having a tooth surface design margin.
The design allowance of the tooth surface is reserved for the next cold extrusion, namely the tooth blank with the tooth shape after the cold extrusion treatment, and the tooth surface is reserved for the next cold extrusion.
In the step 104, the cold extrusion process includes: the die entering temperature of the tooth blank is kept at 80+/-5 ℃, the working temperature of the die is kept at 215+/-5 ℃, the die stripping temperature of the tooth blank is kept at 250+/-5 ℃, the tooth surface design allowance, namely the single side of the tooth surface allowance is 0.4mm, and the die size is designed according to the linear expansion coefficient of the tooth blank at 250 ℃ and the tooth surface design allowance.
105: and after the cold extrusion treatment is finished, carrying out stress relief annealing treatment on the tooth blank under a protective atmosphere, and after the stress relief annealing treatment is finished, continuing to carry out necessary processing and then carrying out macromolecule lubrication treatment.
Specifically, the stress relief annealing treatment includes: preserving heat at 800 ℃ for 8 hours, then cooling to 730 ℃ for 2 hours, then cooling to 680 ℃ for 2 hours, then cooling to 530 ℃ for 4 hours, and then cooling with a furnace. At this time, the hardness can be reduced to below 135HB, and the grains at the deformation part are more refined.
The destressing annealing is performed on the basis of spheroidizing annealing and cold extrusion, so that the annealing temperature of 800 ℃ is set, the structure is further refined, the purpose of 730 ℃ heat preservation is to preserve heat at the highest temperature after the structure is transformed, the structure stress is reduced, and the purpose of 530 ℃ heat preservation is to reduce the thermal stress.
The necessary processing before the polymer lubrication treatment can comprise finish machining of the upper end face, the lower end face and the outer circle so as to ensure the roundness and the coaxiality of the outer circle and ensure the flatness and the perpendicularity of the two end faces.
106: after the stress relief annealing treatment is completed, the gear blank is subjected to precise cold extrusion treatment, and the gear precision after the precise cold extrusion can reach 6.5-7.0 levels.
In step 106, the extrusion amount of the tooth surface in the precision cold extrusion process is equal to the design margin of the tooth surface.
In the step 106, the precision cold extrusion process includes: the die-in temperature of the tooth blank is kept at 100+/-5 ℃, the working temperature of the die is kept at 110+/-5 ℃, the die-out temperature of the tooth blank is kept at 135+/-5 ℃, and the die size is designed according to the linear expansion coefficient of the tooth blank at 135 ℃ and the design allowance of the tooth surface.
107: after the precision cold extrusion treatment is completed, carburizing and quenching treatment is carried out, so that the high-precision gear is obtained, the gear precision is 7.5 grade, and the use requirement of the product is not met.
In the description of the present application, it should be noted that the azimuth or positional relationship indicated by the terms "upper", "lower", etc. are based on the azimuth or positional relationship shown in the drawings, and are merely for convenience of describing the present application and simplifying the description, and are not indicative or implying that the apparatus or element in question must have a specific azimuth, be constructed and operated in a specific azimuth, and thus should not be construed as limiting the present application. Unless specifically stated or limited otherwise, the terms "mounted," "connected," and "coupled" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present application can be understood by those of ordinary skill in the art according to the specific circumstances.
It should be noted that in the present application, relational terms such as "first" and "second" and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
The foregoing is only a specific embodiment of the application to enable those skilled in the art to understand or practice the application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. The processing technology of the high-precision gear is characterized by comprising the following steps of:
spheroidizing annealing treatment is carried out on the tooth blank so that the hardness of the tooth blank is reduced below a first hardness threshold value;
after the spheroidizing annealing treatment is finished, carrying out cold extrusion treatment on the tooth blank so as to enable the tooth blank to form a tooth shape, wherein the tooth surface of the tooth blank with the tooth shape is provided with a tooth surface design allowance;
after the cold extrusion treatment is finished, carrying out stress relief annealing treatment on the tooth blank so as to reduce the hardness of the tooth blank below a second hardness threshold value;
after the stress relief annealing treatment is finished, performing precise cold extrusion treatment on the tooth blank to obtain a high-precision gear;
wherein the extrusion amount of the tooth surface in the precision cold extrusion treatment is equal to the tooth surface design allowance.
2. The process for manufacturing a high-precision gear according to claim 1, wherein:
the spheroidizing annealing treatment comprises: preserving heat for 10-12 h at 750-770 ℃, then cooling to 670-690 ℃ and preserving heat for 22-26 h, and then cooling with a furnace.
3. The process for manufacturing a high-precision gear according to claim 1, wherein:
the stress relief annealing treatment comprises: heat preservation is carried out for 7 to 9 hours at 790 to 810 ℃, then the temperature is reduced to 720 to 740 ℃ for 1 to 3 hours, then the temperature is reduced to 670 to 690 ℃ for 1 to 3 hours, then the temperature is reduced to 530 to 550 ℃ for 4 to 5 hours, and then the furnace is cooled.
4. The process for manufacturing a high-precision gear according to claim 1, wherein:
the cold extrusion process includes: the die-in temperature of the tooth blank is 75-85 ℃, the working temperature of the die is 180-220 ℃, the die-out temperature of the tooth blank is 220-260 ℃, and the size of the die is obtained based on the shape and the size of the high-precision gear to be manufactured, the tooth surface allowance single side, the die-out temperature and the linear expansion coefficient corresponding to the die-out temperature.
5. The process for manufacturing a high-precision gear according to claim 1, wherein:
the precision cold extrusion treatment comprises the following steps: the die-in temperature of the tooth blank is 95-105 ℃, the working temperature of the die is 105-125 ℃, the die-out temperature of the tooth blank is 115-135 ℃, and the size of the die is obtained based on the shape and the size of the high-precision gear to be manufactured, the tooth surface allowance single side, the die-out temperature and the linear expansion coefficient corresponding to the die-out temperature.
6. The process for manufacturing a high-precision gear according to claim 1, wherein:
the first hardness threshold is 145HB;
and/or the second hardness threshold is 135HB.
7. The process for manufacturing a high-precision gear according to claim 1, wherein:
before the tooth blank is subjected to spheroidizing annealing treatment, the processing technology further comprises the following steps: sawing the bar stock to a specified size, heating and then finishing upsetting and punching on forging equipment.
8. The process for manufacturing a high-precision gear according to claim 1, wherein:
after the spheroidizing annealing treatment is finished and before the cold extrusion treatment is carried out on the tooth blank, the processing technology further comprises the following steps: shot blasting and polymer lubrication are sequentially performed.
9. The process for manufacturing a high-precision gear according to claim 1, wherein:
after the stress relief annealing treatment is completed and before the precise cold extrusion treatment is carried out on the tooth blank, the processing technology further comprises the following steps: and (5) high polymer lubrication treatment.
10. The process for manufacturing a high-precision gear according to claim 1, wherein:
after the tooth blank is subjected to the precise cold extrusion treatment, the processing technology further comprises the following steps: carburizing and quenching treatment.
CN202310824557.6A 2023-07-06 2023-07-06 Processing technology of high-precision gear Pending CN116926284A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310824557.6A CN116926284A (en) 2023-07-06 2023-07-06 Processing technology of high-precision gear

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310824557.6A CN116926284A (en) 2023-07-06 2023-07-06 Processing technology of high-precision gear

Publications (1)

Publication Number Publication Date
CN116926284A true CN116926284A (en) 2023-10-24

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