High-frequency quenching treatment process for electric tool accessories

Abstract

The invention relates to the field of metal heat treatment, and discloses a high-frequency quenching treatment process for electric tool accessories. The high-frequency quenching treatment process for the electric tool accessories comprises the following steps that S1, to-be-treated accessories are subjected to pre-cleaning and batch charging; s2, carrying out high-frequency heating treatment on the assembled to-be-treated accessory to obtain a pretreated accessory; s3, the pretreated accessory is subjected to quenching cooling treatment through quenching oil, and a quenched accessory is obtained; s4, the quenched accessory is subjected to post-cleaning and post-tempering treatment, and a tempered accessory is obtained; and S5, the tempered accessory is subjected to post-treatment, and the electric tool accessory is obtained. The tempering temperature is greater than the quenching cooling temperature, the temperature difference between the tempering temperature and the quenching cooling temperature is 20-40 DEG C, and the hardness of the quenched accessory-the hardness of the tempered accessory is greater than or equal to 2HRC. Through high-frequency quenching treatment and tempering treatment, the hardness difference of the parts subjected to quenching treatment and tempering treatment is controlled, the motor tool parts have the advantages of being uniform in hardness, not prone to deformation and free of cracks, and the batch production yield is high.

Description

Technical Field

[0001] This application relates to the field of metal heat treatment. More specifically, it relates to a high-frequency quenching treatment process for electric tool accessories. Background Art

[0002] High-frequency quenching is a heat treatment process that utilizes the principle of electromagnetic induction to cause the surface of the accessory to generate an induced current and rapidly heat to the quenching temperature under the action of a high-frequency alternating magnetic field, and then rapidly cool. It can significantly improve the surface hardness, wear resistance, and fatigue strength of the accessory, while the core still maintains good toughness. Currently, it is widely used in fields such as automobiles, machinery manufacturing, military, aerospace, etc., to process parts such as gears, shafts, and molds to meet their high requirements for surface hardness and wear resistance under complex working conditions.

[0003] As a common type of shaft accessory, electric tool accessories are generally made of alloy structural steel, with the characteristics of small size, compact structure, and high requirements for coaxiality and precision. The requirements for their high-frequency quenching process are more stringent.

[0004] In the prior art, the performance stability of accessories is generally adjusted by controlling the process parameters of high-frequency quenching, such as time and temperature, or by performing multiple high-frequency quenching processes. However, due to the characteristics of electric tool accessories, in the actual mass production process, it is difficult to ensure the uniformity of heating and cooling during the processing of accessories, resulting in problems such as local deformation, uneven hardness, or cracks in the accessories, thereby affecting the yield rate of batch production of accessories. Summary of the Invention

[0005] In order to solve the problem of low yield rate of electric tool accessories with small size and high overall structural precision in the mass production process, this application provides a high-frequency quenching treatment process for electric tool accessories.

[0006] This application provides a high-frequency quenching treatment process for electric tool accessories, adopting the following technical solutions: A high-frequency quenching treatment process for electric tool accessories includes the following steps: S1. Pre-clean and batch load the accessories to be processed; S2. Perform high-frequency heating treatment on the loaded accessories to be processed to obtain pre-treated accessories; S3. Quench and cool the pre-treated accessories with quenching oil to obtain quenched accessories; S4. Post-clean the quenched accessories and then perform tempering treatment to obtain tempered accessories; S5. Post-treat the tempered accessories to obtain electric tool accessories; During quenching and tempering processes, the tempering temperature is higher than the quenching temperature, and the temperature difference between the tempering temperature and the quenching temperature is 20 - 40°C. It is controlled that the hardness of the quenched fitting - the hardness of the tempered fitting ≥ 2HRC.

[0007] By adopting the above - mentioned technical solution, it can effectively solve the problems of deformation, uneven hardness or cracks caused by uneven heating and cooling during the high - frequency quenching process of power tool fittings. The fittings can effectively remove surface oil stains and impurities through pre - cleaning, ensuring the uniformity of subsequent high - frequency heating treatment. The high - frequency heating treatment enables the surface of the fittings to quickly reach the quenching temperature, significantly improving the surface hardness while reducing the possibility of core deformation. The quenching and cooling treatment uses quenching oil to ensure a uniform and appropriate - depth cooling process, further enhancing the surface performance of the fittings and inhibiting crack generation. The tempering treatment relieves internal stress and optimizes the overall toughness and stability of the fittings. By reasonably controlling the quenching and cooling temperature and the tempering temperature, the tempering temperature is higher than the quenching temperature, ensuring that the temperature difference is maintained within the range of 20 - 40°C, thereby optimizing the thermal stress distribution and reducing the unevenness in the treatment of batch fittings; controlling the difference between the hardness of the quenched fittings and the tempered fittings ≥ 2HRC ensures that the surface of the fittings has sufficient hardness to improve wear resistance, while the core still maintains good toughness, balancing the stress on the fittings, further improving the performance stability and the yield rate of batch production of the obtained power tool fittings, reducing the situations of local deformation, uneven hardness or cracks, and enhancing the yield rate of batch production.

[0008] The applicant found in mass production that after the fittings are batch - loaded, the intervals between a large number of fittings are small. In the high - frequency quenching process, the quality difference between the fittings in the middle position and those in the edge position is large. If the interval between the fittings is increased, the number of workpieces in batch loading will decrease, and the processing efficiency will be reduced. Therefore, the small - batch production process is not applicable to mass production. Through the above - mentioned process of this application, through high - frequency heating treatment, quenching treatment and tempering treatment, and controlling the temperature difference and hardness difference of the fittings during quenching and tempering treatments, the thermal stress distribution is optimized, the unevenness in the treatment of batch fittings is reduced, and the yield rate of mass production of the fittings is improved.

[0009] Preferably, the high - frequency heating current in the S2 step is 960 - 1080A, the heating time is 6.8 - 7.8s, and the holding time after heating is 38 - 51min.

[0010] By adopting the above technical solution, the relatively optimal high-frequency heating current and time can ensure that a batch of fittings can quickly reach the ideal quenching temperature within a moderate time range, improve the heating efficiency and reduce the defects caused by uneven temperature; the holding time after heating is 38 - 51 min, which helps the heat to fully conduct inside the batch of fittings, ensuring the temperature consistency of the fittings at each position of the batch loading tooling and the core and surface of a single fitting, and improving the uniformity and stability of the subsequent quenching treatment.

[0011] Preferably, the quenching and cooling temperature in the step S3 is 40 - 90 °C, the quenching and cooling time is 1 - 2 min, and the quenching depth ≥ 1.08 mm.

[0012] By adopting the above technical solution, the relatively optimal quenching and cooling time and temperature can effectively ensure the stability of the cooling performance of the quenching oil, avoid the problem of uneven cooling caused by too high or too low temperature, and thus reduce the risks of uneven hardness, deformation and cracks of the fittings. At the same time, the quenching depth ≥ 1.08 mm ensures the thickness of the quenched layer, improves the hardness and wear resistance of the surface of the fittings, and meets the performance requirements of the electric tool fittings under the working conditions.

[0013] Preferably, the viscosity of the quenching oil at 40 °C is 16 - 25 mm2 / s.

[0014] By adopting the above technical solution, controlling the viscosity of the quenching oil at 40 °C to be 16 - 25 mm 2 / s can effectively adjust the cooling rate during quenching. During quenching, the surface of the fittings is cooled quickly and evenly, avoiding problems such as uneven hardness, deformation or cracks caused by too fast or too slow cooling rate, thereby improving the hardness consistency and overall quality of the fittings after quenching.

[0015] Preferably, the tempering time is 40 - 60 min.

[0016] By adopting the above technical solution, controlling the tempering treatment time within the range of 40 - 60 min can effectively ensure the temperature uniformity and stress release effect of the fittings during tempering. Reduce the problems of stress residue caused by too short tempering time or material property degradation caused by too long tempering time, thereby improving the overall performance stability of the fittings and the consistency of batch production.

[0017] Preferably, the post-treatment includes sandblasting treatment. Steel sand is used to sandblast the tempered fittings, the sandblasting pressure is 0.3 - 0.5 MPa, the particle size of the steel sand is 0.1 mm - 0.2 mm, and the hardness of the steel sand is 55 - 60 HRC.

[0018] By adopting the above technical solutions, sandblasting can effectively remove the scale and impurities on the surface of tempered fittings, improve the surface cleanliness and roughness, and thus enhance the adhesion of the subsequent coating of the fittings. At the same time, by controlling the sandblasting pressure to be 0.3 - 0.5 MPa, it is ensured that the sandblasting process can achieve the cleaning effect without causing excessive damage to the surface of the fittings. The particle size of the steel sand is 0.1 mm - 0.2 mm, which can ensure the cleaning efficiency while avoiding surface scratches caused by too large particles or incomplete cleaning caused by too small particles. Selecting steel sand with a hardness of 55 - 60 HRC can match the hardness requirements of power tool fittings, effectively clean the surface while maintaining the dimensional accuracy and shape integrity of the fittings, and reduce problems such as deformation or cracks of the fittings.

[0019] Preferably, the quenching oil is composed of 95.5 - 97 wt% of a quenching oil matrix and 3 - 4.5 wt% of a penetration coolant, and the penetration coolant is composed of polyisobutylene bis-succinimide, triethylene glycol diacetate, and diethylene glycol.

[0020] By adopting the above technical solutions, when the commonly used quenching oil is applied to the batch production process, its penetration and infiltration performance for the batch-loaded fittings is relatively low. Therefore, in this application, by adding a relatively optimal proportion of penetration coolant to the quenching oil matrix, and the penetration coolant is composed of polyisobutylene bis-succinimide, triethylene glycol diacetate, and diethylene glycol, the cooling performance and penetration ability of the quenching oil can be significantly improved.

[0021] Preferably, the weight ratio of polyisobutylene bis-succinimide, triethylene glycol diacetate, and diethylene glycol is 1:(0.2 - 0.5):(1.2 - 1.5).

[0022] By adopting the above technical solutions, further optimizing the weight ratio of polyisobutylene bis-succinimide, triethylene glycol diacetate, and diethylene glycol can significantly improve the penetration and cooling performance of the quenching oil. Polyisobutylene bis-succinimide has significant penetration and dispersion performance, which can enable the quenching oil to quickly penetrate and disperse to the surface of a large number of fittings. Through the further synergistic effect with triethylene glycol diacetate and diethylene glycol, the cooling uniformity of the quenching oil can be improved, enabling the fittings located in the middle position of the batch-loading tooling to also come into contact with the quenching oil for quenching in a timely manner, reducing the quenching non-uniformity of the batch of fittings, and improving the surface performance and overall batch quality of the fittings.

[0023] Preferably, the material of the fitting is 4140 alloy structural steel.

[0024] By adopting the above technical solutions, 4140 alloy structural steel is commonly used for power tool fittings, which has good hardness, wear resistance, and toughness, and can meet the high requirements of power tool fittings for dimensional accuracy, coaxiality, and overall precision.

[0025] Preferably, the hardness of the quenched fitting is 56 - 61 HRC, and the hardness of the tempered fitting is 50 - 53 HRC.

[0026] By adopting the above technical solution, the hardness is adjusted to balance the stress of the fitting, avoiding problems of local deformation or cracks caused by uneven hardness or a large difference in hardness, thereby significantly improving the yield rate and overall performance stability of the electric tool fitting.

[0027] In summary, the present application includes at least one of the following beneficial technical effects: 1. The high-frequency quenching treatment process of the electric tool fitting of the present application, through the optimized design of steps such as pre-cleaning, high-frequency heating treatment, quenching cooling, tempering, and post-treatment, controls the temperature difference between the tempering temperature and the quenching cooling temperature to be 20 - 40 °C, and ensures that the hardness difference between the quenched fitting and the tempered fitting is ≥2 HRC, solving the problem of low yield rate caused by uneven heating and cooling during the mass production of electric tool fittings, and improving the yield rate of mass production.

[0028] 2. The quenching cooling treatment adopts a specific temperature range (40 - 90 °C) and time (1 - 2 min) and combines with quenching oil. Taking the quenching oil as the matrix, a penetration coolant composed of polyisobutylene bis-succinimide, triethylene glycol diacetate, and diethylene glycol is added in a preferred proportion, ensuring that the quenching depth is ≥1.08 mm, enabling the fittings located in the middle position of the batch loading tooling to come into contact with the quenching oil for quenching in a timely manner, reducing the quenching non-uniformity of the batch of fittings, and improving the surface performance and overall batch quality of the fittings.

[0029] 3. Controlling the optimal high-frequency heating current, time, and holding time after heating can ensure that the batch of fittings can quickly reach the ideal quenching temperature within a moderate time range, improving the heating efficiency and reducing defects caused by uneven temperature, ensuring the consistency of the temperature of the fittings at each position of the batch loading tooling and the core and surface of a single fitting, and improving the uniformity and stability of the subsequent quenching treatment. Description of the Drawings Figure 1 is a flowchart of a high-frequency quenching treatment process for an electric tool fitting in Embodiment 1 of the present application. Detailed Embodiments

[0031] The following combines the attached Figure 1 and embodiments to further elaborate on the present application.

[0032] The following are the sources and specifications of some raw materials of the present application. The raw materials used in the preparation examples and embodiments of the present application can all be obtained commercially, including but not limited to the raw materials of the following models and manufacturers. Raw materials with the same performance can all be used: 1. Polyisobutylene bis-succinimide: Model T154; 2. Triethylene glycol diacetate: CAS No. 111-21-7, content 99%; 3. Diethylene glycol: CAS No. 111-46-6, content 99%; 4. Commercially available quenching oil: SASO-QUENCH G100, viscosity at 40°C is 16-25mm 2 / s; 5. High frequency quenching machine: input voltage 380V±10%, frequency 50-60Hz. Example

[0033] Example 1 Example 1 discloses a high-frequency quenching process for electric tool accessories, referring to Figure 1 . The following steps are included: S1. The parts to be processed are sprayed with water for cleaning, and then 100 parts to be processed are placed horizontally on the loading tooling, with 20 parts in a row, a total of 5 rows, and a 2mm interval between two parts in the same row, and a 3cm interval between each row, to complete batch loading. The parts are 4140 alloy structural steel shafts, 15cm long and 0.8cm in diameter, with a toothed structure in the middle along the length direction; S2. Use a high-frequency quenching machine, adjust the frequency to 50 Hz, perform high-frequency heating treatment on the batch-assembled accessories to be processed, control the high-frequency heating current to 960A, the heating time to 7s, and the holding time after heating to 51min to obtain pre-treated accessories; S3, quenching and cooling the pretreated parts using commercially available quenching oil, the quenching and cooling temperature is 40° C., the quenching and cooling time is 1 min, the quenching depth is 1.08 mm, and the quenched parts are obtained. The hardness of the quenched parts is 56 HRC; S4. The quenched parts are spray-cleaned with a commercially available quenching oil cleaning agent, dried, and then tempered at a tempering temperature of 60° C. for 60 min to obtain tempered parts. The hardness of the tempered parts is 53 HRC. The quenching oil cleaning agent can be any type and can be purchased commercially, so it is not limited here. S5. Use steel grit to sandblast the tempered accessories. The sandblasting pressure is 0.3 MPa. The particle size of the steel grit is 0.1 mm. The hardness of the steel grit is 55 HRC. The steel grit model is G25, and electric tool accessories are obtained.

[0034] Example 2-3 The difference between Example 2-3 and Example 1 is that the preparation process parameters are different, see Table 1 below for details.

[0035] Table 1 Parameters of Examples 1-3 Example 4 The difference between Example 4 and Example 1 is that in step S2, the heating time is 5 s, and the others are the same as those in Example 1.

[0036] Example 5 The difference between Example 5 and Example 1 is that in step S3, the quenching and cooling time is 4 min.

[0037] Example 6 The difference between Example 6 and Example 1 is that the quenching oil is different. The quenching oil in Example 6 consists of 95.5 wt% commercially available quenching oil as the matrix and 4.5 wt% penetration coolant. The penetration coolant consists of polyisobutylene bis-succinimide, triethylene glycol diacetate and diethylene glycol with a weight ratio of 1:0.2:1.2, and the others are the same as those in Example 1.

[0038] Example 7 The difference between Example 7 and Example 1 is that the quenching oil in Example 7 consists of 97 wt% commercially available quenching oil as the matrix and 3 wt% penetration coolant. The penetration coolant consists of polyisobutylene bis-succinimide, triethylene glycol diacetate and diethylene glycol with a weight ratio of 1:0.5:1.5, and the others are the same as those in Example 1.

[0039] Example 8 The difference between Example 8 and Example 6 is that the dosage of the penetration coolant is 92 wt% and the dosage of the penetration coolant is 8 wt%, and the others are the same as those in Example 6.

[0040] Example 9 The difference between Example 9 and Example 6 is that polyisobutylene bis-succinimide in the penetration coolant is replaced with polyisobutylene in equal amount, and the others are the same as those in Example 6.

[0041] Example 10 The difference between Example 10 and Example 6 is that triethylene glycol diacetate in the penetration coolant is replaced with diethylene glycol in equal amount, and the others are the same as those in Example 6.

[0042] Example 11 The difference between Example 11 and Example 6 is that diethylene glycol in the penetration coolant is replaced with neopentyl glycol in equal amount, and the others are the same as those in Example 6.

[0043] Comparative Example Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the temperature of quenching and cooling is 110 °C, and the others are the same as those in Example 1.

[0044] Comparative Example 2 The difference between Comparative Example 2 and Example 1 is that the tempering temperature is 100°C, and the others are the same as in Example 1.

[0045] Performance detection test The following is a performance test on the power tool accessories prepared in Examples 1-11 and Comparative Examples 1-2: 1. Hardness test: Select 50 accessories from 100 accessories, with 10 accessories selected from each row. The 10 accessories include 4 accessories at the middle positions and 6 accessories at the edge positions. Use a Rockwell hardness tester to detect the hardness at the left, middle, and right positions of each accessory, and take the average value. If 50 ≤ hardness ≤ 53, it is considered qualified. Count the number of qualified accessories, calculate the qualification rate, and test and record the test results.

[0046] 2. Martensite grade test: Select 50 accessories from 100 accessories, with 10 accessories selected from each row. The 10 accessories include 4 accessories at the middle positions and 6 accessories at the edge positions. Use a metallurgical microscope to test the martensite grade. A grade of 6 is considered qualified. Count the number of qualified accessories, calculate the qualification rate, and test and record the test results.

[0047] The following are the performance test data of the power tool accessories prepared in Examples 1-11 and Comparative Examples 1-2. For details, see Table 2 below.

[0048] Table 2 Performance data table of Examples 1-11 and Comparative Examples 1-2 Combining Examples 1-3 and Example 4, it can be seen that by optimizing the high-frequency heating time, the batch qualification rate of the prepared accessories is improved. This may be because the relatively optimal high-frequency heating time improves the heating uniformity of the batch of accessories.

[0049] Combined with Examples 1-3, Example 5, and Comparative Examples 1-2, it can be seen that in Example 5, the quenching time was increased, and the batch qualification rate of the produced fittings decreased. This may be because the quenching time was too long, resulting in large changes in the internal stress of the fittings, and problems such as insufficient hardness and deformation were likely to occur. The hardness and metallographic structure of the fittings at different positions were non-uniform, thus reducing the batch qualification rate of the fittings. In Comparative Example 1, the quenching temperature was increased, making the quenching temperature higher than the tempering temperature. The qualification rates of the hardness and metallographic structure of the batch of fittings both decreased significantly. This may be because the internal stress inside the batch of fittings could not be released well, resulting in non-uniform performance of the fittings at local and different positions, reducing the batch qualification rate of the fittings. In Comparative Example 2, the tempering temperature was increased, making the temperature difference between the tempering temperature and the quenching temperature greater than 40°C. The qualification rates of the hardness and metallographic structure of the produced batch of fittings decreased. This may be because the change in the temperature difference made the thermal stress distribution of the batch of fittings non-uniform, thereby reducing the batch qualification rate of the fittings.

[0050] Combined with Examples 1-3 and Examples 6-11, it can be seen that by using quenching oil as the matrix and adding a relatively optimal proportion of a penetration coolant composed of polyisobutylene bis-succinimide, triethylene glycol diacetate, and diethylene glycol to the quenching oil, the batch qualification rate of the fittings can be further improved. Compared with Example 6, in Example 8, the dosage of the penetration coolant was increased, and the performance of the produced batch of fittings decreased significantly. This may be because the relatively large dosage of the penetration coolant damaged the emulsion system stability of the quenching oil matrix, producing a counter-effect, thus significantly reducing the batch qualification rate of the fittings. Compared with Example 6, in Examples 9-11, the component raw materials of the penetration coolant were changed, and the batch qualification rate of the produced fittings also decreased. This may be because the synergistic effect of the three components was reduced, resulting in a decrease in the dispersion and penetration uniformity of the batch of fittings.

[0051] This specific embodiment is only an explanation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications without creative contributions to this embodiment as needed, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A high-frequency quenching treatment process for electric tool accessories, characterized in that, It includes the following steps: S1. Perform pre - cleaning and batch loading on the parts to be processed; S2. Perform high - frequency heating treatment on the loaded parts to be processed to obtain pre - treated parts; S3. Perform quenching and cooling treatment on the pre - treated parts with quenching oil to obtain quenched parts; S4. Perform post - cleaning on the quenched parts and then perform tempering treatment to obtain tempered parts; S5. Perform post - treatment on the tempered parts to obtain power tool parts; During the quenching and cooling treatment and the tempering treatment, the tempering temperature is higher than the quenching and cooling temperature, the temperature difference between the tempering temperature and the quenching and cooling temperature is 20 - 40°C, and it is controlled that the hardness of the quenched parts - the hardness of the tempered parts ≥ 2HRC.

2. The high-frequency quenching treatment process of the electric tool accessory according to claim 1, characterized in that: The high - frequency heating current in step S2 is 960 - 1080A, the heating time is 6.8 - 7.8s, and the holding time after heating is 38 - 51min.

3. The high-frequency quenching treatment process of the electric tool accessory according to claim 1, characterized in that: The quenching and cooling temperature in step S3 is 40 - 90°C, the quenching and cooling time is 1 - 2min, and the quenching depth ≥ 1.08mm.

4. The high-frequency quenching treatment process of the electric tool accessory according to claim 1, characterized in that: The viscosity of the quenching oil at 40 °C is 16 - 25 mm 2 / s.

5. The high-frequency quenching treatment process of the electric tool accessory according to claim 1, characterized in that: The tempering time is 40 - 60min.

6. The high-frequency quenching treatment process for the electric tool accessory according to claim 1, characterized in that: The post - treatment includes sandblasting treatment. The tempered parts are sandblasted with steel sand. The sandblasting pressure is 0.3 - 0.5MPa, the particle size of the steel sand is 0.1mm - 0.2mm, and the hardness of the steel sand is 55 - 60 HRC.

7. The high-frequency quenching treatment process for the electric tool accessory according to claim 1, characterized in that: The quenching oil is composed of 95.5 - 97wt% of a quenching oil matrix and 3 - 4.5wt% of a penetration coolant. The penetration coolant is composed of polyisobutylene bis - succinimide, triethylene glycol diacetate, and diethylene glycol.

8. The high-frequency quenching treatment process of the electric tool accessory according to claim 7, characterized in that: The weight ratio of polyisobutylene bis - succinimide, triethylene glycol diacetate, and diethylene glycol is 1:(0.2 - 0.5):(1.2 - 1.5).

9. The high-frequency quenching treatment process of the electric tool accessory according to claim 1, characterized in that: The material of the parts is 4140 alloy structural steel.

10. The high-frequency quenching treatment process of the electric tool accessory according to claim 9, characterized in that: The hardness of the quenched parts is 56 - 61HRC, and the hardness of the tempered parts is 50 - 53HRC.

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