Special quenching oil for precision gears, preparation and use method

Abstract

The application discloses a quenching oil special for precision gears, a preparation method and a use method, the material of the precision gears is 20CrMnTi or 20Cr2Ni4 or 17CrNiMo6, and the quenching oil is characterized by comprising 20-80 parts of base oil, 2-10 parts of a cooling catalyst, 0.2-1.0 parts of a surfactant and 0.2-2 parts of an antioxidant. The cooling catalyst at least comprises a mixture of polyisobutylene maleic anhydride and any one of trimethylolpropane tris-n-nonylate, pentaerythritol tetra-n-nonylate and bis-pentaerythritol ester, and the mass ratio is (2-5):(1-2). The polyisobutylene maleic anhydride is applied to the field of quenching oil, when the polyisobutylene maleic anhydride and polyisobutylene are used as the cooling catalyst due to the similar properties, the service life of the quenching oil is unexpectedly prolonged on the basis of the optimal cooling characteristics, the anti-aging ability and the hot shear ability are improved, the generation of oil dirt is inhibited, the waste of the quenching oil in the quenching process is reduced, and the cost is lowered.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of metal heat treatment, in particular to a quenching oil special for precision gears, a preparation method and a use method. BACKGROUND

[0002] Quenching is the most important process in the heat treatment process. Quenching is a process of heating steel above the critical point, holding for a certain time, and then rapidly cooling in a quenching medium to obtain a martensitic structure. The purpose of quenching is to increase the hardness and wear resistance of steel, and to obtain good comprehensive mechanical properties of parts. Common quenching media include salt water, water, mineral oil, air, etc.

[0003] The commonly used materials for precision gears include medium carbon steel (such as 45 steel) and low and medium carbon alloy steel, such as 20Cr, 40Cr, 20CrMnTi, cast iron, cloth-wood or nylon, etc. During the quenching process of precision gears, excessive temperature or slow cooling speed will lead to poor quenching effect, thereby affecting the quality of the gears. Therefore, the temperature and cooling speed must be strictly controlled to ensure the quality of gear quenching.

[0004] Currently, the quenching oil for precision gears uses base oil, quenching agent, antioxidant, brightener and surfactant. The quenching agent is represented by polyisobutylene, and some technologies add polyol ester and dialkylnaphthalene to ensure the cooling performance, such as CN109593930A and CN105950844A. The antioxidant is represented by amine and phenolic antioxidant, such as CN105950844A. The amine will undergo oxidation reaction under high temperature, resulting in increased viscosity, discoloration and other phenomena. Especially for gears with complex surface structure, the hardness layer cannot be obtained with the same thickness as the tooth part at the tooth root, leading to uneven hardness and even micro-cracks. The brightener is represented by imidazoline oleate and methyl terpene resin, such as CN111304419A. The brightener will undergo decomposition reaction under high temperature, producing harmful substances. At the same time, due to the failure of the brightener, the adsorption amount of the quenching oil on the gear surface is increased, resulting in increased consumption. Therefore, the gear surface cannot be cleaned, and "mottling" phenomenon will occur during the tempering process. SUMMARY

[0005] The technical problem to be solved by the present application is how to ensure uniform and consistent quenching hardness of precision gears, without mottling during the tempering stage, and effectively reduce the addition of additives affecting the performance of the quenching oil while ensuring the antioxidant ability and cooling performance.

[0006] In order to solve the above technical problems, the inventors have summarized and obtained the technical scheme of the present application through practice. The present application adopts the following technical scheme:

[0007] The application discloses a quenching oil special for precision gears, and the precision gears are made of 20CrMnTi, 20Cr2Ni4 or 17CrNiMo6, and the quenching oil is characterized by comprising 20-80 parts of base oil, 2-10 parts of a cooling agent, 0.2-1.0 parts of a surfactant and 0.2-2 parts of an antioxidant.

[0008] The cooling agent comprises a mixture of polyisobutylene maleic anhydride and any one of trimethylolpropane trinormal nonanoate, pentaerythritol tetranormal nonanoate and bis-pentaerythritol ester, and the mass ratio is (2-5):(1-2).

[0009] The polyisobutylene maleic anhydride is introduced into the cooling agent of the quenching oil, the maleic anhydride is introduced on the basis of the superior cooling performance of polyisobutylene, the service life of the quenching oil is unexpectedly prolonged, the anti-aging ability and the hot shear ability are improved, the generation of oil dirt is inhibited, the waste of the quenching oil in the quenching process is reduced, the cost is lowered, the problem of oil mud dispersibility after the quenching oil is used for a period of time is solved, the cleaning performance of the quenching oil is maintained, the surface quality of the quenched gears is improved, the brightening effect is achieved, the surfactant is used in cooperation, the adsorption amount of the quenching oil on the surface of the parts is reduced, the consumption is reduced, the'mottling' phenomenon caused by the incomplete cleaning of the parts in the tempering process is reduced, the superior stability of the quenching oil at high temperature is achieved, the film breaking temperature is improved, and the uniformity of the quenching hardness of the precision gears is ensured.

[0010] Further, the cooling agent further comprises polyisobutylene, and the mass ratio of the polyisobutylene to the polyisobutylene maleic anhydride is 1:(3-6).

[0011] Further, the cooling agent comprises 1-2 parts of polyisobutylene maleic anhydride, 0.2-0.6 parts of polyisobutylene, and 0.2-1 parts of trimethylolpropane trinormal nonanoate.

[0012] Further, the kinematic viscosity of the base oil is 10-230 mm2 / s, and the acid value is less than or equal to 0.3 mgKOH / g.

[0013] Further, the surfactant is at least one of sodium dioctyl sulfosuccinate, sodium linear alkyl benzene sulfonate, cocodiethanolamide and N-tert-butyl-2-benzothiazole sulfenamide.

[0014] Further, the antioxidant comprises a mixture of phosphonate antioxidant and phenolic antioxidant, and the mass fraction ratio of the phosphonate antioxidant to the phenolic antioxidant is (3-5):1.

[0015] The phosphite antioxidant is combined with phenolic antioxidant and polyisobutylene maleic anhydride, and a synergistic effect is usually generated. The synergistic effect can improve the antioxidant effect of the antioxidant, and also can reduce the amount of the antioxidant, thereby reducing the environmental impact. The antioxidants can act together and complement each other to resist harmful substances such as free radicals and peroxides generated during the use of quenching oil. These harmful substances can cause problems such as oxidative degradation and discoloration of the material, thereby affecting the performance and service life of the material.

[0016] Meanwhile, a large amount of phosphite antioxidant and a small amount of phenolic antioxidant are used to improve the thermal oxidation stability, and the problems of oil stains and large amount of quenching oil adsorbed on the surface of the gear caused by the use of methacrylate polymer or amine antioxidant at high temperature are avoided.

[0017] Further, the phosphite antioxidant is at least one of triphenyl phosphite, tetra(2,4-di-tert-butylphenyl) 4,4'-biphenylene diphosphonite, diphenyl alkyl phosphite, and phenyl dialkyl phosphite.

[0018] Further, the phenolic antioxidant is at least one of 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol, and 2,6-di-tert-butyl-4-ethylphenol.

[0019] The application also discloses a preparation method of the quenching oil, and specifically comprises the following steps.

[0020] 1) Two-thirds of the total amount of base oil is weighed according to the proportion, 2-10 parts of a quenching agent are added and uniformly mixed at a temperature of 40-55 DEG C and in an inert gas atmosphere to obtain quenching oil A liquid;

[0021] 2) Half of the remaining amount of refined base oil is weighed according to the proportion, 0.2-3 parts of an antioxidant are added and uniformly mixed at a temperature of 30-45 DEG C and in an inert gas atmosphere to obtain quenching oil B liquid;

[0022] 3) Half of the remaining amount of refined base oil is weighed according to the proportion, 0.2-0.5 parts of a surfactant are added and uniformly mixed at a temperature of 30-45 DEG C and in an inert gas atmosphere to obtain quenching oil C liquid;

[0023] Quenching oil B liquid and quenching oil C liquid are simultaneously added dropwise into quenching oil A liquid under stirring, the dropwise adding speed of quenching oil C liquid is 1-3 times that of quenching oil B liquid, the dropwise adding speed of quenching oil C liquid is (0.2-0.6) parts / min, and the dropwise adding process is still in an inert gas atmosphere;

[0024] 4) After the quenching oil B and quenching oil C are added completely, cool to room temperature at a speed of 2-5℃ / min to obtain the quenching oil for precision gear.

[0025] Further, the quenching oil has a kinematic viscosity of 20-50mm2 / s and a using temperature of 40-130℃.

[0026] A method for using the quenching oil for precision gear, the using steps are as follows:

[0027] Heat the workpieces of 20Cr2Ni4 and 17CrNiMo6 to 830-860℃;

[0028] Heat the workpieces of 20CrMnTi to 880-900℃;

[0029] Put the gear workpieces into the quenching oil tank under a closed and inert atmosphere, and open the internal stirring of the quenching oil tank to make the internal quenching oil move up and down and rotate the gear for quenching and cooling treatment.

[0030] The quenching oil tank is provided with a coating structure which is suitable for sticking quenching oil to the root of the gear to reduce the tension between the quenching oil and the surface of the gear.

[0031] The coating structure comprises a rotating disc which is driven to rotate by a servo motor as a power source, a penetrating rod is installed in the middle of the rotating disc and is suitable for penetrating the quenching gear without differential motion in the circumferential direction, a coating ring is installed on the rotating disc, and bristles of a cotton or hemp product are installed on the inner side of the coating ring and are suitable for coating quenching oil at the first time when the quenching gear contacts the quenching oil; the servo motor is located outside the quenching oil tank.

[0032] A movable closure cover is provided on the top of the quenching oil tank, a lifter is provided on the inner top of the movable closure cover and is suitable for lowering the penetrating rod with the quenching gear, gas exchange pipes one and two are provided on the upper part of the movable closure cover, the gas exchange pipe one is suitable for introducing inert gas, and the gas exchange pipe two is suitable for leading out air when the inert gas is introduced, an oil fume condensation and recovery structure is provided on the top of the movable closure cover, the condensation and recovery structure comprises a plurality of condensation plates and a condenser which is suitable for providing a cooling atmosphere for the condensation plates and the atmosphere around the condensation plates, and a collection box is provided on the bottom of the plurality of condensation plates and is suitable for collecting and introducing quenching oil into the quenching oil tank.

[0033] In use, the penetrating rod with the quenching gear is hung by the lifter in the movable closure cover, the movable closure cover is adjusted to be located on the top of the quenching oil tank so that the quenching oil tank is in a closed state, the inert gas is introduced through the gas exchange pipe one and the air is led out through the gas exchange pipe two so that the movable closure cover is in an inert atmosphere.

[0034] The quenching gear is inserted into the quenching oil tank, and the quenching gear is driven by the servo motor to rotate, and the quenching gear is in contact with the quenching oil in the quenching oil tank, so that the quenching oil is coated on the quenching gear, and the quenching oil is coated on the quenching gear.

[0035] Compared with the prior art, the present application has the following advantages:

[0036] 1) In the research process, it is found that adding traditional quenching agents such as polyisobutylene and / or dialkylnaphthalene or their mixtures alone cannot achieve the purpose of adjusting the cooling speed of quenching oil.

[0037] In particular, the application of polyisobutylene maleic anhydride in the field of quenching oil makes use of the similar properties of polyisobutylene maleic anhydride and polyisobutylene as quenching agents, and makes use of its optimal cooling characteristics, unexpectedly prolongs the service life of quenching oil, improves its anti-aging ability, thermal shear ability, surface quality, flowability and viscosity, etc.

[0038] Due to the introduction of anhydride groups, the high-temperature resistance of the quenching oil is more superior, and the high-temperature condition can have superior stability, and the film breaking temperature is improved. When the mass ratio of polyisobutylene to polyisobutylene maleic anhydride is 1:6, the excellent anti-oxidation performance and high-temperature film breaking performance are exhibited, and when the mass ratio is higher than 1:4, the viscosity will increase, which is not conducive to the hardening treatment of the root position, and it is also not easy to clean, which will increase the consumption of quenching oil.

[0039] Polyisobutylene mainly improves the cooling speed of quenching oil, and has good effect, while trimethylolpropane tris-n-nonylate, pentaerythritol tetra-n-nonylate and bis-pentaerythritol ester are mainly used to realize precise control of the cooling performance of quenching oil in a small range, so as to be used for gears of different sizes.

[0040] When the quenching agent is selected from polyisobutylene maleic anhydride 1-2 parts, polyisobutylene 0.2-0.6 parts, trimethylolpropane tris-n-nonylate 0.2-1 parts, the cooling effect and anti-aging ability, thermal shear ability, surface quality, flowability, viscosity and other properties are optimal.

[0041] The quenching oil can meet the requirements of workpiece quenching quality, has stable cooling performance, oxidation resistance stability and safety stability during long-term use, is suitable for use under harsh conditions of high temperature and continuous operation for a long time (the continuous use time can be prolonged for a longer time; after being opened, it can be stored for more than 4 years without failure in the light-shielded, cool and dry place), and the input cost of the quenching oil is reduced due to the fact that the cooling characteristics of the quenching oil do not need to be remedied by frequently adding additives (especially brightener).

[0042] 2) The phosphonate antioxidant, the phenolic antioxidant and the polyisobutylene maleic anhydride are used together, a synergistic effect is generated, the antioxidant effect of the antioxidant is improved, the amount of the antioxidant is reduced, and the influence on the environment is reduced.

[0043] The phosphonate antioxidant, the phenolic antioxidant and the polyisobutylene maleic anhydride can jointly act and complement each other to resist harmful substances such as free radicals and peroxides generated during the use of the quenching oil. The harmful substances can cause problems such as oxidation degradation and discoloration of the material, thereby affecting the performance and service life of the material.

[0044] The phosphonate antioxidant and the phenolic antioxidant are used together to improve the thermal oxidation stability, and the problems of oil dirt and large amount of quenching oil adsorbed on the surface of a part caused by the fact that the methacrylate polymer or the amine antioxidant is used are avoided.

[0045] 3) The quenching oil tank and the movable closed cover are used together to make the quenching be in a closed and inert atmosphere, prevent the quenching oil from being seriously lost, prevent the surface of the workpiece from being oxidized by contacting air, ensure that the quenching oil is coated on the gear root at the first time when the quenching gear contacts the quenching oil, prevent the surface tension from being increased and the gear root from being unable to fully contact the quenching oil after repeated use, and ensure the quenching quality. BRIEF DESCRIPTION OF DRAWINGS

[0046] Fig. 1 It is a whole structure schematic diagram of quenching of the present application;

[0047] Fig. 2 It is a whole structure schematic diagram of the rotating disc of the present application;

[0048] Fig. 3 It is a whole structure top view of the rotating disc of the present application;

[0049] Fig. 4 It is a whole structure side sectional view of quenching of the present application. DETAILED DESCRIPTION

[0050] The technical solutions of the present application will be described in detail below in combination with specific embodiments.

[0051] The kinematic viscosity of the base oil is 10–230 mm² / s, and the acid value is ≤0.3 mg KOH / g.

[0052] A quenching oil for precision gears, wherein the precision gears are made of 20CrMnTi, 20Cr2Ni4, or 17CrNiMo6, comprising 20-80 parts base oil, 2-10 parts refrigerant, 0.2-1.0 parts surfactant, and 0.2-2 parts antioxidant;

[0053] The cooling agent includes a mixture of polyisobutylene maleic anhydride and any one of trimethylolpropane tri-n-nonanoate, pentaerythritol tetra-n-nonanoate and dipentaerythritol ester, in a mass ratio of (2-5):(1-2).

[0054] The surfactant is at least one of sodium dioctyl dibutyrate sulfonate, sodium linear alkylbenzene sulfonate, cocoyl diethanolamide, and N-tert-butyl-2-benzothiazole sulfenamide.

[0055] Among them, antioxidants include a mixture of phosphonate antioxidants and phenolic antioxidants, with a mass fraction ratio of (3-5):1 between phosphonate antioxidants and phenolic antioxidants.

[0056] Phosphate antioxidants are at least one of triphenyl phosphite, tetrakis(2,4-di-tert-butylphenyl)4,4'-biphenyl diphosphite, diphenylalkyl phosphite, and phenyl dialkyl phosphite.

[0057] The phenolic antioxidant is at least one of 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol, and 2,6-di-tert-butyl-4-ethylphenol.

[0058] Example 1: Quenching oil for precision gears. The precision gear material is 20CrMnTi. The main components of the quenching oil are: 50 parts base oil, 4 parts refrigerant, 0.3 parts surfactant, and 0.5 parts antioxidant. The refrigerant is preferably polyisobutylene maleic anhydride and trimethylolpropane tri-n-nonanoate in a ratio of 3:1. The surfactant is preferably sodium dioctyl dibutyrate sulfonate and cocoyl diethanolamide in a mass ratio of 2:1. The mass ratio of phosphonate antioxidants to phenolic antioxidants is 4:1. The phosphonate antioxidants are preferably triphenyl phosphite and diphenylalkyl phosphite in a mass ratio of 1:1. The phenolic antioxidants are 2,6-di-tert-butyl-4-methylphenol and 2-tert-butyl-4,6-dimethylphenol in a mass ratio of 1:1.

[0059] A method for preparing a quenching oil specifically for precision gears, comprising the following steps:

[0060] 1) Weigh two-thirds of the total amount of base oil, add 4 parts of quenching agent and mix evenly at a temperature of 40-55°C under an inert gas atmosphere to obtain quenching oil A liquid;

[0061] 2) Weigh half of the remaining amount of refined base oil, add 0.5 parts of antioxidant and mix evenly at a temperature of 30-45°C under an inert gas atmosphere to obtain quenching oil B liquid;

[0062] 3) Weigh half of the remaining amount of refined base oil, add 0.3 parts of surfactant and mix evenly at a temperature of 30-45°C under an inert gas atmosphere to obtain quenching oil C liquid;

[0063] While stirring, quenching oil B liquid and quenching oil C liquid are simultaneously added dropwise into quenching oil A liquid, the dropwise addition speed of quenching oil C liquid is 2 times that of quenching oil B liquid, the dropwise addition speed of quenching oil C liquid is 0.4 parts / min, and the dropwise addition process is still under an inert gas atmosphere;

[0064] 4) After quenching oil B liquid and quenching oil C liquid are completely added, cooling is carried out at a speed of 3°C / min to room temperature to obtain the precision gear special quenching oil, the kinematic viscosity of the quenching oil is 22 mm2 / s, and the use temperature is 60°C.

[0065] The quenching oil prepared in this example has good thermal oxidation stability, significant cooling effect, high film breaking temperature, good flowability, and good low-temperature detergency, especially for quenching treatment at the tooth root position, which can efficiently and high-quality complete quenching treatment, so that the precision gear of 20CrMnTi material has uniform and consistent quenching hardness, no cracks, uniform martensite internal organization, and no speckle after gear tempering, etc. After opening, it can be stored in the dark, cool and dry place for 4 years without failure. The main point is that the use of polyisobutylene maintains superior cooling effect, and the introduction of maleic anhydride fundamentally solves the side effects after the addition of brightener, while also maintaining almost equivalent effect.

[0066] The combination of phosphonate antioxidant, phenolic antioxidant and polyisobutylene maleic anhydride can reduce the use of antioxidant, and together resist harmful substances such as free radicals and peroxides generated during the use of quenching oil, so that the quenching oil slows down deterioration and oil dirt, and saves 1.5 kg of consumption per ton of gear workpiece.

[0067] Example 2, a quenching oil special for precision gears, the material of the precision gears is 20CrMnTi, the main components of the quenching oil and the components are as follows: 55 parts of base oil, 4.5 parts of quenching agent, 0.3 parts of surfactant and 0.6 parts of antioxidant, the quenching agent is preferably polyisobutylene maleic anhydride and trimethylolpropane tris-n-nonylate, the ratio is 3:1; the surfactant is preferably sodium dioctyl sulfosuccinate and cocamide diethanol, the mass ratio is 2:1; the mass ratio of phosphonate antioxidant and phenolic antioxidant is 3:1, the phosphonate antioxidant is preferably triphenyl phosphite and diphenyl alkyl phosphite, the mass ratio is 1:1, the mass ratio of phenolic antioxidant is 2,6-di-tert-butyl-4-methylphenol and 2-tert-butyl-4,6-dimethylphenol is 1:1.

[0068] A preparation method of a quenching oil special for precision gears, the preparation steps are as follows:

[0069] 1) Two-thirds of the total amount of base oil is weighed according to the proportion, 4 parts of quenching agent is added and mixed uniformly at a temperature of 40-55°C and under an inert gas atmosphere to obtain quenching oil A liquid;

[0070] 2) Half of the remaining amount of refined base oil is weighed according to the proportion, 0.5 parts of antioxidant is added and mixed uniformly at a temperature of 30-45°C and under an inert gas atmosphere to obtain quenching oil B liquid;

[0071] 3) Half of the remaining amount of refined base oil is weighed according to the proportion, 0.3 parts of surfactant is added and mixed uniformly at a temperature of 30-45°C and under an inert gas atmosphere to obtain quenching oil C liquid;

[0072] Quenching oil B liquid and quenching oil C liquid are simultaneously added dropwise into quenching oil A liquid while stirring, the dropwise adding speed of quenching oil C liquid is twice that of quenching oil B liquid, the dropwise adding speed of quenching oil C liquid is 0.4 parts / min, and the dropwise adding process is still under an inert gas atmosphere;

[0073] 4) After quenching oil B liquid and quenching oil C liquid are completely added, cooling to room temperature at a speed of 3°C / min to obtain the quenching oil special for precision gears, the kinematic viscosity of the quenching oil is 24 mm2 / s, and the use temperature is 75°C.

[0074] The quenching oil prepared by the embodiment has good thermal oxidation stability, remarkable cooling effect, high film breaking temperature, good fluidity, and good low-temperature detergency, so that the precision gear of 20CrMnTi material has uniform and consistent quenching hardness, no cracks, and uniform martensite internal organization, and the gear tempering has no mottling and other advantages. After opening, it can be stored in the dark, cool and dry place for 4 years without failure. The main point is that the use of polyisobutylene maintains superior cooling effect, and the introduction of maleic anhydride fundamentally solves the side effects after the addition of brightener, while almost equivalent effect can be maintained.

[0075] The phosphonate antioxidant, the phenolic antioxidant, and the polyisobutylene maleic anhydride are used together, which can reduce the use of antioxidants, jointly resist harmful substances such as free radicals and peroxides generated during the use of quenching oil, slow down the deterioration of quenching oil and the generation of oil dirt, and save 1.4 kg of consumption per ton of gear workpiece. The polyisobutylene maleic anhydride can not only act as an emulsifier but also disperse the insoluble substances in the quenching oil, prevent accumulation, and facilitate cleaning. The gear tempering has no mottling phenomenon.

[0076] In embodiment 3, the quenching oil for precision gears is prepared, the material of the precision gear is 20Cr2Ni4, and the main components and components of the quenching oil are as follows: 60 parts of base oil, 4 parts of quenching agent, 0.4 parts of surfactant, and 0.6 parts of antioxidant. The quenching agent is preferably polyisobutylene maleic anhydride and trimethylolpropane tris-n-nonylate, and the ratio is 4:1. The surfactant is preferably sodium dioctyl sulfonate and cocodiethanolamide, and the mass fraction is 2:1. The mass fraction ratio of phosphonate antioxidant and phenolic antioxidant is 4:1. The phosphonate antioxidant is preferably triphenyl phosphite and diphenyl alkyl phosphite, and the mass fraction ratio is 1:1. The phenolic antioxidant is 2,6-di-tert-butyl-4-methylphenol and 2-tert-butyl-4,6-dimethylphenol, and the mass fraction ratio is 1:1.

[0077] A preparation method of a quenching oil for precision gears is provided, and the preparation steps are as follows:

[0078] 1) Two-thirds of the total amount of base oil is weighed according to the proportion, 4 parts of quenching agent are added and mixed uniformly at a temperature of 40-55°C and in an inert gas atmosphere to obtain quenching oil A liquid;

[0079] 2) Half of the remaining amount of refined base oil is weighed according to the proportion, 0.6 parts of antioxidant are added and mixed uniformly at a temperature of 30-45°C and in an inert gas atmosphere to obtain quenching oil B liquid;

[0080] 3) Half of the remaining amount of refined base oil is weighed according to the proportion, 0.4 parts of surfactant are added and mixed uniformly at a temperature of 30-45°C and in an inert gas atmosphere to obtain quenching oil C liquid;

[0081] Quenching oil B liquid and quenching oil C liquid are simultaneously added dropwise into quenching oil A liquid while stirring, the dropwise adding speed of quenching oil C liquid is 2 times that of quenching oil B liquid, the dropwise adding speed of quenching oil C liquid is 0.4 parts / min, and the dropwise adding process is still kept in an inert gas atmosphere;

[0082] 4) After quenching oil B liquid and quenching oil C liquid are completely added, cooling is performed at a speed of 3 ℃ / min to room temperature to obtain the special quenching oil for precision gears, the kinematic viscosity of the quenching oil is 28 mm2 / s, and the use temperature is 80 ℃.

[0083] The quenching oil prepared in the embodiment has good thermal oxidation stability, significant cooling effect, high film breaking temperature, good fluidity, and good low-temperature detergency, so that the precision gears made of 20Cr2Ni4 material have uniform and consistent quenching hardness, no cracks, uniform internal organization form of martensite, and no speckles during gear tempering, and the like. After being opened, the quenching oil can be stored in a dark, cool, and dry place for 4 years without failure. The main point is that the use of polyisobutylene maintains superior cooling effect, and the introduction of maleic anhydride fundamentally solves the side effects after the addition of brightener, while almost equivalent effects can be maintained.

[0084] The phosphonate antioxidant is used in combination with the phenolic antioxidant and polyisobutylene maleic anhydride, which can reduce the use of antioxidants, and together resist harmful substances such as free radicals and peroxides generated during the use of quenching oil, so as to slow down the deterioration of quenching oil and the generation of oil dirt, and save 1.6 kg of consumption per ton of gear workpiece.

[0085] Example 4, a special quenching oil for precision gears, the material of the precision gear is 20Cr2Ni4, the main components of the quenching oil and each component are as follows: 65 parts of base oil, 5 parts of quenching agent, 0.4 parts of surfactant, and 0.7 parts of antioxidant, the quenching agent is preferably polyisobutylene maleic anhydride and trimethylolpropane tris-n-nonylate, the ratio is 4:1; the surfactant is preferably sodium dioctyl sulfosuccinate and cocamide diethanol, the mass fraction is 2:1; the mass fraction ratio of the phosphonate antioxidant and the phenolic antioxidant is 4:1, the phosphonate antioxidant is preferably triphenyl phosphite and diphenyl alkyl phosphite, the mass fraction ratio is 1:1, and the mass fraction ratio of the phenolic antioxidant is 2,6-di-tert-butyl-4-methylphenol and 2-tert-butyl-4,6-dimethylphenol is 1:1.

[0086] A preparation method of a special quenching oil for precision gears, the preparation steps are as follows:

[0087] 1) Two-thirds of the total amount of base oil is weighed according to the proportion, 5 parts of quenching agent are added and uniformly mixed at a temperature of 40 ℃ to 55 ℃ and kept in an inert gas atmosphere to obtain quenching oil A liquid;

[0088] 2) Take the remaining half of the refined base oil by proportion, add 0.7 parts of antioxidant and mix evenly at 30-45℃ and keep in inert gas atmosphere to obtain quenching oil B liquid;

[0089] 3) Take the remaining half of the refined base oil by proportion, add 0.4 parts of surfactant and mix evenly at 30-45℃ and keep in inert gas atmosphere to obtain quenching oil C liquid;

[0090] While stirring, quenching oil B liquid and quenching oil C liquid are added into quenching oil A liquid at the same time, the drop adding speed of quenching oil C liquid is twice that of quenching oil B liquid, the drop adding speed of quenching oil C liquid is 0.4 parts / min, and the drop adding process is still kept in inert gas atmosphere;

[0091] 4) After quenching oil B liquid and quenching oil C liquid are completely added, cool to room temperature at a speed of 3℃ / min to obtain the quenching oil for precision gear, the kinematic viscosity of the quenching oil is 30mm2 / s, and the use temperature is 100℃.

[0092] The quenching oil prepared in this example has good thermal oxidation stability, significant cooling effect, high film breaking temperature, good flowability, and good low temperature detergency, so that the precision gear of 20Cr2Ni4 material has uniform and consistent quenching hardness, no cracks, uniform internal organization form of martensite, and no speckle after gear tempering, etc. After opening, it can be stored in the dark, cool and dry place for 4 years without failure. The main point is that the use of polyisobutylene maintains superior cooling effect and introduces maleic anhydride to fundamentally solve the side effects after the addition of brightener, while also maintaining almost equivalent effect.

[0093] The phosphonate antioxidant, the phenolic antioxidant and the polyisobutylene maleic anhydride are used together, which can reduce the use of antioxidant, jointly resist harmful substances such as free radicals and peroxides generated during the use of quenching oil, so that the quenching oil appears to slow down deterioration and oil dirt, and 1.5kg of consumption per ton of gear workpiece is saved.

[0094] In example 5, the quenching oil for precision gear, the material of the precision gear is 17CrNiMo6, the main components of the quenching oil and each component are 70 parts of base oil, 6 parts of quenching agent, 0.6 parts of surfactant and 1.2 parts of antioxidant, the quenching agent is preferably polyisobutylene maleic anhydride and trimethylolpropane tris-n-nonylate with a ratio of 5:1; the surfactant is preferably sodium dioctyl sulfosuccinate and cocamide diethanol with a mass ratio of 2:1; the mass ratio of phosphonate antioxidant and phenolic antioxidant is 4:1, the phosphonate antioxidant is preferably triphenyl phosphite and diphenyl alkyl phosphite with a mass ratio of 1:1, and the mass ratio of phenolic antioxidant is 2,6-di-tert-butyl-4-methylphenol and 2-tert-butyl-4,6-dimethylphenol is 1:1.

[0095] A preparation method of a quenching oil special for precision gears, the preparation steps are as follows:

[0096] 1) Two-thirds of the total amount of base oil is weighed according to the proportion, 6 parts of a quencher are added and mixed uniformly at a temperature of 40-55°C and under an inert gas atmosphere to obtain quenching oil A liquid;

[0097] 2) Half of the remaining amount of refined base oil is weighed according to the proportion, 1.2 parts of an antioxidant are added and mixed uniformly at a temperature of 30-45°C and under an inert gas atmosphere to obtain quenching oil B liquid;

[0098] 3) Half of the remaining amount of refined base oil is weighed according to the proportion, 0.6 parts of a surfactant are added and mixed uniformly at a temperature of 30-45°C and under an inert gas atmosphere to obtain quenching oil C liquid;

[0099] Quenching oil B liquid and quenching oil C liquid are simultaneously added dropwise into quenching oil A liquid while stirring, the dropwise adding speed of quenching oil C liquid is 2 times that of quenching oil B liquid, the dropwise adding speed of quenching oil C liquid is 0.4 parts / min, and the dropwise adding process is still under an inert gas atmosphere;

[0100] 4) After quenching oil B liquid and quenching oil C liquid are completely added, cooling is performed to room temperature at a speed of 4°C / min to obtain the quenching oil special for precision gears, the kinematic viscosity of the quenching oil is 20-50 mm2 / s, and the use temperature is 120°C.

[0101] The quenching oil prepared in the example has good thermal oxidation stability, significant cooling effect, high film breaking temperature, good flowability, and good low-temperature detergency, so that the precision gear made of 17CrNiMo6 material has uniform and consistent quenching hardness, no cracks, uniform martensite internal organization, and no speckle after gear tempering, etc. After opening, it can be stored in the dark, cool and dry place for 4 years without failure. The main point is that the use of polyisobutylene maintains the superior cooling effect, and the introduction of maleic anhydride fundamentally solves the side effects after the addition of brightener, while almost equivalent effect is maintained.

[0102] The phosphonate antioxidant is used in combination with phenolic antioxidant and polyisobutylene maleic anhydride, which can reduce the use of antioxidant, jointly resist harmful substances such as free radicals and peroxides generated during the use of quenching oil, slow down the deterioration of quenching oil and oil dirt, and save 1.5 kg of consumption per ton of gear workpiece.

[0103] Example 6, a quenching oil special for precision gears, the material of the precision gears is 17CrNiMo6, the main components of the quenching oil and the components are as follows: 75 parts of base oil, 6 parts of quenching agent, 0.4 parts of surfactant and 0.8 parts of antioxidant, the quenching agent is preferably polyisobutylene maleic anhydride and trimethylolpropane tri-n-nonylate, the ratio is 2:1; the surfactant is preferably sodium dioctyl sulfosuccinate and cocodiethanolamide, the mass ratio is 2:1; the mass ratio of phosphonate antioxidant and phenolic antioxidant is 4:1, the phosphonate antioxidant is preferably triphenyl phosphite and diphenyl alkyl phosphite, the mass ratio is 1:1, the mass ratio of phenolic antioxidant is 2,6-di-tert-butyl-4-methylphenol and 2-tert-butyl-4,6-dimethylphenol is 1:1.

[0104] A preparation method of a quenching oil special for precision gears, the preparation steps are as follows:

[0105] 1) Two-thirds of the total amount of base oil is weighed according to the proportion, 6 parts of quenching agent is added and mixed uniformly at a temperature of 40-55°C and under an inert gas atmosphere to obtain quenching oil A liquid;

[0106] 2) Half of the remaining amount of refined base oil is weighed according to the proportion, 0.8 parts of antioxidant is added and mixed uniformly at a temperature of 30-45°C and under an inert gas atmosphere to obtain quenching oil B liquid;

[0107] 3) Half of the remaining amount of refined base oil is weighed according to the proportion, 0.4 parts of surfactant is added and mixed uniformly at a temperature of 30-45°C and under an inert gas atmosphere to obtain quenching oil C liquid;

[0108] Quenching oil B liquid and quenching oil C liquid are simultaneously added dropwise into quenching oil A liquid while stirring, the dropwise adding speed of quenching oil C liquid is twice that of quenching oil B liquid, the dropwise adding speed of quenching oil C liquid is 0.4 parts / min, and the dropwise adding process is still under an inert gas atmosphere;

[0109] 4) After quenching oil B liquid and quenching oil C liquid are completely added, cooling to room temperature at a speed of 3°C / min to obtain the quenching oil special for precision gears, the kinematic viscosity of the quenching oil is 30 mm2 / s, and the use temperature is 100°C.

[0110] The quenching oil prepared in the embodiment has good thermal oxidation stability, remarkable cooling effect, high film breaking temperature, good fluidity, and good low-temperature detergency, so that the precision gear of 17CrNiMo6 material has uniform and consistent quenching hardness, no cracks, and uniform martensite internal organization, and the gear tempering has no mottling and other advantages. After opening, it can be stored in the dark, cool and dry place for 4 years without failure. The main point is that the use of polyisobutylene maintains the superior cooling effect, and the addition of maleic anhydride fundamentally solves the side effects after the addition of brightener, while almost equivalent effects can be maintained.

[0111] The phosphonate antioxidant, the phenolic antioxidant, and the polyisobutylene maleic anhydride are used together, which can reduce the use of antioxidants, jointly resist harmful substances such as free radicals and peroxides generated during the use of quenching oil, slow down the deterioration of quenching oil, and save 1.4 kg of consumption per ton of gear workpiece.

[0112] In embodiment 7, the quenching oil for precision gears is prepared, the material of the precision gear is 20CrMnTi, and the main components and components of the quenching oil are as follows: 70 parts of base oil, 5 parts of cooling agent, 0.3 parts of surfactant, and 0.7 parts of antioxidant. The cooling agent is preferably polyisobutylene maleic anhydride and trimethylolpropane tris-n-nonylate with a ratio of 3:1; the surfactant is preferably sodium dioctyl sulfosuccinate and cocamide diethanol with a mass ratio of 2:1; the mass ratio of phosphonate antioxidant and phenolic antioxidant is 4:1; the phosphonate antioxidant is preferably triphenyl phosphite and diphenyl alkyl phosphite with a mass ratio of 1:1; and the mass ratio of phenolic antioxidant is 2,6-di-tert-butyl-4-methylphenol and 2-tert-butyl-4,6-dimethylphenol with a mass ratio of 1:1.

[0113] Polyisobutylene is also added as a cooling agent, and the mass ratio of polyisobutylene to polyisobutylene maleic anhydride is 1:4.

[0114] A preparation method of a quenching oil for precision gears, the preparation steps are as follows:

[0115] 1) Two-thirds of the total amount of base oil is weighed according to the proportion, 5 parts of cooling agent are added and mixed uniformly at a temperature of 40-55°C and in an inert gas atmosphere to obtain quenching oil A liquid;

[0116] 2) Half of the remaining amount of refined base oil is weighed according to the proportion, 0.7 parts of antioxidant are added and mixed uniformly at a temperature of 30-45°C and in an inert gas atmosphere to obtain quenching oil B liquid;

[0117] 3) Half of the remaining amount of refined base oil is weighed according to the proportion, 0.3 parts of surfactant are added and mixed uniformly at a temperature of 30-45°C and in an inert gas atmosphere to obtain quenching oil C liquid;

[0118] The quenching oil B and the quenching oil C were simultaneously added dropwise into the quenching oil A while stirring, the dropwise adding speed of the quenching oil C was 2 times of that of the quenching oil B, the dropwise adding speed of the quenching oil C was 0.4 parts / min, and the dropwise adding process was still kept in the inert gas atmosphere;

[0119] 4) After the quenching oil B and the quenching oil C were completely added, cooling was carried out to room temperature at a speed of 4 ℃ / min to obtain the quenching oil special for precision gears, the kinematic viscosity of the quenching oil was 28 mm2 / s, and the use temperature was 100 ℃.

[0120] The quenching oil prepared in the example has good thermal oxidation stability, significant cooling effect, high film breaking temperature, good fluidity and good low-temperature detergency, so that the precision gear made of 20CrMnTi material has uniform and consistent quenching hardness, no cracks, uniform martensite internal organization, and no speckle after gear tempering, etc. After opening, it can be stored in the dark, cool and dry place for 4 years without failure. The main point is that the use of polyisobutylene maintains superior cooling effect, and the introduction of maleic anhydride fundamentally solves the side effects after the addition of brightener, while almost equivalent effect can be maintained.

[0121] The phosphonate antioxidant is used together with the phenolic antioxidant and the polyisobutylene maleic anhydride, which can reduce the use of antioxidants, and together resist harmful substances such as free radicals and peroxides generated during the use of quenching oil, so that the quenching oil slows down the deterioration and oil dirt, and 1.1 kg of consumption per ton of gear workpiece is saved.

[0122] The difference from example 1 is that the proportion of polyisobutylene is increased, and this example is suitable for thin precision gears below 20 mm thick, which is beneficial to the consistency of core hardness and working surface hardness, and no cracks occur.

[0123] Comparative example 1

[0124] The components of the traditional gear quenching oil are: 50 parts of base oil, 4 parts of cold complexing agent, 0.5 parts of brightener, 0.3 parts of surfactant, and 0.5 parts of antioxidant, wherein the kinematic viscosity of the base oil is 10-230 mm2 / s, and the acid value is ≤0.3 mgKOH / g.

[0125] The cold complexing agent is a mixture of polyisobutylene and dialkyl naphthalene (the mass ratio of the two is 2:1).

[0126] The brightener is a mixture of imidazoline oleate and methyl terpene resin (the mass ratio is 1:1).

[0127] The antioxidant is alkylated diphenylamine (CAS No. 68921-45-9);

[0128] The surfactant is sodium dioctyl sulfosuccinate (CAS No. 577-11-7).

[0129] The preparation method is as follows:

[0130] 1) Two-thirds of the total amount of base oil is weighed proportionally, 4 parts of quenching agent are added and mixed uniformly at a temperature of 40-55°C and under an inert gas atmosphere to obtain quenching oil A liquid;

[0131] 2) Half of the remaining amount of refined base oil is weighed proportionally, 0.5 parts of antioxidant are added and mixed uniformly at a temperature of 30-45°C and under an inert gas atmosphere to obtain quenching oil B liquid;

[0132] 3) Half of the remaining amount of refined base oil is weighed proportionally, 0.3 parts of surfactant and 0.5 parts of brightener are added and mixed uniformly at a temperature of 30-45°C and under an inert gas atmosphere to obtain quenching oil C liquid;

[0133] While stirring, quenching oil B liquid and quenching oil C liquid are simultaneously added dropwise into quenching oil A liquid, the dropwise addition speed of quenching oil C liquid is twice that of quenching oil B liquid, the dropwise addition speed of quenching oil C liquid is 0.4 parts / min, and the dropwise addition process is still under an inert gas atmosphere;

[0134] 4) After quenching oil B liquid and quenching oil C liquid are completely added, cooling is performed at a speed of 4°C / min to room temperature to obtain quenching oil.

[0135] The cooling performance, thermal oxidation stability of the quenching oil and the gear surface state after quenching are comprehensively evaluated by using SH / T0219 heat treatment oil thermal oxidation stability test method, SH / T0220 heat treatment oil cooling performance test method and heat treatment oil brightness determination method, respectively.

[0136]

[0137] Any of examples 1 to 7 has lower carbon residue increase, lower viscosity ratio and almost equivalent brightness compared with comparative example 1.

[0138] In summary, the application of polyisobutylene maleic anhydride in quenching oil field is a bold attempt of the inventor, and the polyisobutylene maleic anhydride used in the application is mainly synthesized by heat synthesis of polyisobutylene and maleic anhydride as raw materials. The polyisobutylene maleic anhydride not only maintains the excellent cooling performance of quenching oil due to polyisobutylene, but also improves the high-temperature stability of quenching oil due to the introduction of maleic anhydride, thereby increasing the film breaking temperature and preventing the brittle skin phenomenon caused by rapid cooling, especially the rapid cooling of the tooth root position which is prone to cracks. At the same time, the low-temperature cleaning performance is improved to ensure the cleanliness of the gear working surface and reduce the residual quenching oil on the working surface to prevent the occurrence of tempering spots. In addition, the phosphonate antioxidant and phenolic antioxidant are used together to reduce the use of antioxidants and to jointly resist the harmful substances such as free radicals and peroxides generated during the use of quenching oil.

[0139] During the research, it was found that the polyisobutylene maleic anhydride must be used with a certain proportion of phosphonate antioxidant and phenolic antioxidant to exhibit excellent performance. During the experiment, the inventor tried to replace the phosphonate antioxidant and phenolic antioxidant in the application with other types of antioxidants, such as amine and phenolic antioxidants or amine and phosphonate antioxidants or methacrylate polymer antioxidant combined with one or more of amine, phenolic antioxidant, and phosphonate antioxidant. However, it was found that the effect was not ideal, which may be due to the special reaction of amine antioxidant and methacrylate polymer antioxidant caused by the introduction of maleic anhydride at high temperature, resulting in the failure of these antioxidants.

[0140] The technical solutions in the embodiments of the application will be clearly and completely described below with reference to the drawings in the embodiments of the application. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments of the application.

[0141] In the description of the application, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inner", "outer" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the application.

[0142] A use method of a precision gear special quenching oil, the use steps are as follows:

[0143] Heat the workpieces of 20Cr2Ni4 and 17CrNiMo6 materials to 830-860 DEG C;

[0144] Heat the workpieces of 20CrMnTi material to 880-900 DEG C;

[0145] For example,Figs. 1 to 4 As shown, the gear workpiece is placed in the quenching oil tank 1 under a closed and inert atmosphere, while the internal quenching oil tank 1 is stirred, the internal quenching oil is stirred up and down, and the gear is rotated for quenching cooling treatment;

[0146] The quenching oil tank 1 is provided with a coating structure, which is suitable for sticking quenching oil to the root of the gear to reduce the tension between the quenching oil and the surface of the gear;

[0147] The coating structure includes a rotating disc 2, which is connected with a servo motor 3 as a power source to drive the rotating disc 2 to rotate. The middle part of the rotating disc 2 is provided with a penetrating rod 4, which is suitable for penetrating the quenching gear and has no differential motion in the circumferential direction. The rotating disc 2 is provided with a coating ring 5, and the inner side of the coating ring 5 is provided with a brush 6 made of cotton and hemp products, which is suitable for coating quenching oil at the first time when the quenching gear contacts the quenching oil. The servo motor 3 is located outside the quenching oil tank 1.

[0148] The top of the quenching oil tank 1 is provided with a movable sealing cover 7, and the inner side of the movable sealing cover 7 is provided with a lifter 8 at the top. The lifter 8 is an electric hoist with an electromagnetic adsorption structure, which is suitable for lowering the penetrating rod 4 with the quenching gear. The movable sealing cover 7 is provided with an air exchange pipe one 9 and an air exchange pipe two 10. The air exchange pipe one 9 is suitable for introducing inert gas, and the air exchange pipe two 10 is suitable for leading out air when inert gas is introduced. The top of the movable sealing cover 7 is provided with an oil smoke condensation recovery structure 11, which includes a plurality of condensation plates 12 and a condenser 14 suitable for providing a cooling atmosphere to the condensation plates 12 and the atmosphere around the condensation plates 12. The condenser 14 is a traditional condensing device. The bottom of the plurality of condensation plates 12 is provided with a collection box 13, which is suitable for collecting quenching oil and introducing it into the quenching oil tank 1.

[0149] In use, the penetrating rod 4 with the quenching gear is hung by the lifter 8 in the movable sealing cover 1. The movable sealing cover 7 is adjusted to be located at the top of the quenching oil tank 1, so that the movable sealing cover 1 and the quenching oil tank 1 are in a closed state. Inert gas is introduced through the air exchange pipe one 9, and air is led out through the air exchange pipe two 10, so that the movable sealing cover 7 is in an inert atmosphere.

[0150] The lifter 8 lowers the penetrating rod 4 with the quenching gear into the rotating disc. During the lowering process, the brush coats the quenching oil at the first time when the quenching gear contacts the quenching oil, ensuring that the quenching oil is coated on the root of the gear. At the same time, the internal quenching oil tank 1 is stirred. After the lowering work is completed, the servo motor 3 starts to drive the quenching gear and the rotating disc 2 to rotate simultaneously.

[0151] The above merely describes preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto. The alternatives can be partial structure, device, method step alternatives, or complete technical solutions. According to the technical solutions of the present application and the inventive concept, equivalent replacement or change should be covered within the protection scope of the present application.

Claims

1. A method for using a precision gear quenching oil, characterized in that, The precision gear quenching oil comprises 20-80 parts base oil, 2-10 parts refrigerant, 0.2-1.0 parts surfactant, and 0.2-2 parts antioxidant. The cooling agent includes a mixture of polyisobutylene maleic anhydride and any one of trimethylolpropane tri-n-nonanoate, pentaerythritol tetra-n-nonanoate and dipentaerythritol ester, in a mass ratio of (2-5):(1-2). The usage steps are as follows: Workpieces made of 20Cr2Ni4 and 17CrNiMo6 materials are heated to 830-860℃; The 20CrMnTi workpiece is heated to 880°~900°; In a closed and inert atmosphere, the gear workpiece is placed in the quenching oil tank, and the stirring inside the quenching oil tank is turned on at the same time. The quenching oil inside is turned up and down, and the gear is rotated for quenching and cooling treatment. The quenching oil tank is equipped with a coating structure, which is suitable for adhering quenching oil to the root of the gear, thereby reducing the tension between the quenching oil and the gear surface. The coating structure includes a rotating disk with a servo motor connected to it as a power source to rotate it. A through rod is installed in the middle of the rotating disk, which is suitable for inserting the quenching gear and has no differential motion in the circumferential direction. A coating ring is installed on the rotating disk, and cotton and linen bristles are installed on the inner side of the coating ring. The bristles are suitable for applying quenching oil as soon as the quenching gear comes into contact with the quenching oil. The servo motor is located on the outside of the quenching oil tank. The top of the quenching oil tank is equipped with a movable closed cover. The top of the inner side of the movable closed cover is equipped with a lifter. The lifter is suitable for lowering the insert rod with the quenching gear inserted. The movable closed cover is equipped with a ventilation pipe one and a ventilation pipe two. The ventilation pipe one is suitable for introducing inert gas, and the ventilation pipe two is suitable for leading out air when inert gas is introduced. The top of the movable closed cover is equipped with an oil fume condensation and recovery structure. The condensation and recovery structure includes several condensation plates and a condenser suitable for providing a cooling atmosphere to the condensation plates and the atmosphere around the condensation plates. The bottom of the several condensation plates is equipped with a collection box, which is suitable for collecting quenching oil and introducing it into the quenching oil tank. When in use, the insert rod with the quenching gear is suspended by the lifter inside the movable enclosure. The movable enclosure is adjusted to be at the top of the quenching oil tank, so that the quenching oil tank is in a closed state. Inert gas is introduced through the first air exchange pipe and air is drawn out through the second air exchange pipe, so that the inside of the movable enclosure is inert atmosphere. The lifting device lowers the inserting rod containing the quenched gear into the rotating plate. During the lowering process, the brush bristles apply quenching oil as soon as the quenched gear comes into contact with the quenching oil, ensuring that the root of the gear is coated with quenching oil. At the same time, the stirring inside the quenching oil tank is started. After the lowering is completed, the servo motor starts and drives the quenched gear and the rotating plate to rotate simultaneously.

2. The method of using a precision gear quenching oil according to claim 1, characterized in that, The cooling agent also includes polyisobutylene, and the mass ratio of polyisobutylene to polyisobutylene maleic anhydride is 1:(3-6).

3. The method of using a precision gear quenching oil according to claim 2, characterized in that, The cooling agent comprises 1-2 parts of polyisobutylene maleic anhydride, 0.2-0.6 parts of polyisobutylene, and 0.2-1 parts of trimethylolpropane tri-n-nonanoate.

4. The method of using a precision gear quenching oil according to claim 1, characterized in that, The base oil has a kinematic viscosity of 10–230 mm² / s and an acid value of ≤0.3 mg KOH / g.

5. The method of using a precision gear quenching oil according to claim 1, characterized in that, The surfactant is at least one of sodium dioctyl dibutyrate sulfonate, sodium linear alkylbenzene sulfonate, cocoyl diethanolamide, and N-tert-butyl-2-benzothiazole sulfenamide.

6. The method of using a precision gear quenching oil according to claim 1, characterized in that, The antioxidants include a mixture of phosphonate antioxidants and phenolic antioxidants, with a mass fraction ratio of (3-5):1 for phosphonate antioxidants and phenolic antioxidants.

7. The method of using a precision gear quenching oil according to claim 6, characterized in that, The phosphonate antioxidant is at least one of triphenyl phosphite, tetrakis(2,4-di-tert-butylphenyl)4,4'-biphenyl diphosphite, diphenylalkyl phosphite, and phenyl dialkyl phosphite.

8. The method of using a precision gear quenching oil according to claim 6, characterized in that, The phenolic antioxidant is at least one of 2,6-di-tert-butyl-4-methylphenol, 2-tert-butyl-4,6-dimethylphenol, and 2,6-di-tert-butyl-4-ethylphenol.

9. The method of using a precision gear quenching oil according to claim 1, characterized in that, The preparation steps of the precision gear quenching oil are as follows: 1) Weigh two-thirds of the total amount of base oil according to the proportion, add 2 to 10 parts of refrigerant at a temperature of 40℃~55℃ and in an inert gas atmosphere, and mix evenly to obtain quenching oil A liquid. 2) Weigh out half of the remaining amount of refined base oil according to the proportion, add 0.2 to 3 parts of antioxidant at a temperature of 30℃~45℃ and under an inert gas atmosphere, mix evenly to obtain quenching oil B; 3) Weigh out half of the remaining amount of refined base oil according to the proportion, add 0.2 to 0.5 parts of surfactant at a temperature of 30℃ to 45℃ and under an inert gas atmosphere, and mix evenly to obtain quenching oil C liquid; While stirring, quenching oil B and quenching oil C are simultaneously added dropwise to quenching oil A. The dropwise acceleration of quenching oil C is 1 to 3 times that of quenching oil B, and the dropwise acceleration of quenching oil C is (0.2 to 0.6) parts / min. The dropwise addition process is still maintained in an inert gas atmosphere. 4) After all quenching oil B and quenching oil C have been added, cool to room temperature at a rate of 2-5℃ / min to obtain the precision gear quenching oil. The kinematic viscosity of the quenching oil is 20-50 mm² / s, and the operating temperature is 40-130℃.

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