A method for determining the surface strengthening process of a spinning wheel
By strengthening the surface of the spinning wheel through a surface composite QPQ salt bath treatment process, the problems of low surface strength and short service life of the spinning wheel are solved, and the high wear resistance and service life of the spinning wheel are achieved.
Patent Information
- Application Number
- CN202411603416.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-11
- Publication Date
- 2026-01-30
- Estimated Expiration
- 2044-11-11
AI Technical Summary
The surface strength of the rotating wheel is low and its service life is short. Existing surface strengthening technologies are costly and the process is not stable enough.
The surface of the spinning wheel is strengthened by a surface composite QPQ salt bath treatment process. Through a process of preheating, heating, salt bath heat preservation and exhaust cooling, a 5-8 μm thick strengthening layer is formed, which improves the hardness and wear resistance of the spinning wheel.
The service life of the spinning wheel is increased by 10%, the wear resistance is optimal, the hardness meets the working requirements of the spinning wheel, and the processing cost is reduced.
Smart Images
Figure CN119351940B_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the field of mechanical processing, and particularly relates to a method for determining a surface strengthening process of a spinning roller. BACKGROUND
[0002] Metal spinning forming is a progressive and continuous incremental forming process in which local micro-deformation is accumulated to complete the forming. In each processing moment, the contact area between the spinning roller and the workpiece is small, which can be approximated as point deformation. Therefore, the spinning force is relatively small compared with other pressure processing technologies such as forging, rolling and extrusion. The spinning process can be realized by a small pressure equipment to process large size parts, which is a typical 'low load forming' labor-saving forming process. The force diagram of the contact between the spinning roller and the workpiece is shown in FIG. 1. Figure 1 As shown in the figure, the force between the spinning roller and the workpiece surface during the spinning process is complex. The decompositions of the resultant force P in the radial direction, axial direction and tangential direction are P L , P R and P T' , respectively. The three-direction force determines the complexity and wearability of the spinning roller working condition, in which P L and P R have a direct impact on the wear of the spinning roller. The working profile of the spinning roller is in contact with the workpiece under heavy load and small contact surface extrusion. The spinning roller body is connected with the transmission part. Therefore, the working profile of the spinning roller needs to have high quenching hardness, strength, stiffness, wear resistance and the ability to resist small deformation and certain impact, and needs to have high toughness. The main body of the spinning roller needs to have high strength and toughness, while the hardness cannot be too high, so as to avoid stress concentration and cracking at the sharp corners such as keyways, which affects the rigidity and structural stability of the spinning roller as a whole.
[0003] During the entire spinning forming process, the extrusion force between the contact area of the spinning roller and the workpiece is very large, which can reach several gigapascals. The spinning roller and the workpiece are subjected to severe friction. The apparent quality condition (shape, accuracy, roughness, hardness, etc.) of the working part of the spinning roller will also be directly reflected on the outer surface of the workpiece, as shown in FIG. 2. Figure 2
[0004] According to statistics, currently, one spinning roller needs to be replaced and repaired once for every 180-200 medium and small diameter cylindrical products. It is necessary to select a suitable surface strengthening process to improve the comprehensive performance of the spinning roller surface, reduce failure and prolong the service life. The currently mature surface modification technologies include surface carburizing, surface nitriding, carbonitriding, nitrocarburizing and QPQ technology. Through the strengthening treatment of the surface of the part, the strength of the surface layer material or the prestress state of the surface layer material can be improved to effectively inhibit the generation and development of fatigue cracks, thereby improving the working performance and service life of the spinning roller.
[0005] At present, there are few studies on the surface strengthening technology of spiral gears at home and abroad, and the surface strengthening technology of gears and Cr12MoV die steel can be referred to. At present, the advanced surface strengthening methods include laser cladding, ultrasonic rolling and ultrasonic shot peening technology. In the paper "Study on Wear Resistance of Cr12MoV Die Steel Laser Cladding Composite Ultra-hard Layer[J]. Forging Technology", 2019, 44(08), by Bi Yan et al., a millimeter-level cladding layer is formed by using SKD11 powder laser cladding method, and a micron-level ultra-hard vanadium carbide layer is formed on the laser cladding layer by using TD thermal diffusion method. The composite ultra-hard layer is combined closely, and the wear life is significantly improved.
[0006] In the paper "Research Status and Application of Ultrasonic Shot Peening Surface Strengthening Technology", by Cong Jiahui et al., the influence of ultrasonic shot peening on the surface integrity, fatigue strength and corrosion resistance of materials is summarized, the application status of ultrasonic shot peening is summarized, and it is pointed out that the ultrasonic shot peening technology needs to be combined with basic theory to explore the optimal process parameters and conduct in-depth research to realize the balance of strengthening quality and efficiency, reduce processing cost, and promote large-scale engineering application of ultrasonic shot peening. Dai Qilong et al. theoretically analyzed the ultrasonic rolling process, established a theoretical model of the surface roughness of the sample after ultrasonic rolling, and verified the theoretical model by experiment. Secondly, single factor experiment and orthogonal experiment of ultrasonic rolling were carried out by using ultrasonic rolling device, and the influence law and degree of each process parameter on surface integrity were obtained. The above surface strengthening technologies are in the stage of experiment or popularization and use, and the cost is high, and the process scheme is not stable enough.
[0007] Mature surface strengthening technologies include surface carburizing, surface nitriding, carbonitriding, nitrocarburizing and QPQ technology. Steel carburizing is to heat low-carbon steel to high temperature in a carbon-rich medium, so that active carbon atoms can penetrate into the surface of the steel to obtain a high-carbon layer. Subsequently, quenching and low-temperature tempering are carried out to make the surface have high hardness, wear resistance and fatigue resistance, while the matrix still maintains sufficient strength and toughness. Similarly, steel nitriding is a chemical heat treatment process that allows nitrogen atoms to penetrate the surface of the steel to form a hard nitrogen-rich layer. At present, the above technologies have been maturely applied to engineering practice, and the process method is stable and suitable for batch customization. On this basis, the process of nitriding and carburizing at the same time to promote the diffusion of nitrogen atoms is called nitrocarburizing. QPQ technology is a salt bath liquid nitriding technology, which realizes the combination of nitriding process and oxidation process, generates a double-layer nitriding layer on the surface of the base material, and has the characteristics of high hardness and high wear resistance. SUMMARY
[0008] In order to overcome the low surface strength and short service life of the spiral gear in the prior art, the present application provides a method for determining the surface strengthening process of the spiral gear.
[0009] 1. A method for determining the surface strengthening process of a spiral gear, characterized in that the specific process is:
[0010] Step 1, preparing test block:
[0011] The test block has multiple blocks, which are divided into three test groups, respectively, nitriding treatment test group, nitrocarburizing treatment test group and surface composite QPQ salt bath treatment test group.
[0012] The material of the test block is the same as the runner body; the surface roughness of the test block is ≤Ra0.8.
[0013] Step 2, different nitriding treatment test:
[0014] The surface nitriding treatment test, nitrocarburizing treatment test and surface composite QPQ salt bath treatment test are respectively carried out on the test block of the nitriding treatment test group, the test block of the nitrocarburizing treatment test group and the test block of the surface composite QPQ salt bath treatment test group. Through the analysis of the test data, the surface strengthening process of the runner is determined.
[0015] The nitriding treatment test group is subjected to nitriding treatment. The process route of the surface nitriding treatment is preheating-heating-heat preservation-exhaust cooling, and a strengthened layer with a thickness of 9-12μm is obtained.
[0016] The nitrocarburizing process route is preheating-heating-heat preservation-exhaust cooling; the nitriding layer is the strengthened layer of the test block.
[0017] The surface composite QPQ salt bath treatment process route is preheating-heating-salt bath heat preservation-exhaust cooling; a strengthened layer with a thickness of 5-8μm is obtained.
[0018] Among them: the process of surface nitriding treatment test of the test block of the nitriding treatment test group is that the test blocks in the nitriding treatment test group are heated to 520-550℃ by the heating furnace at a heating rate of 10-15℃ / min. When the test blocks are preheated to 200℃, nitrogen is introduced. After the test blocks are heated to 520-550℃, heat preservation is started; the heat preservation time is 30h. After the heat preservation is over, the furnace is cooled to room temperature. In the nitriding treatment, the ammonia decomposition rate of the nitrogen is 30%-50%.
[0019] The process of surface nitrocarburizing treatment test of the test block of the nitrocarburizing treatment test group is that the test blocks in the nitrocarburizing treatment test group are heated to 630-690℃ by the heating furnace at a heating rate of 10-15℃ / min. When the test blocks are heated to 630-690℃, heat preservation is started; the heat preservation time is 120-180min. After the heat preservation is over, the furnace is cooled to room temperature, and a nitriding layer with a thickness of 5-6μm is obtained on the surface. In the nitrocarburizing treatment, the ammonia gas is introduced at a rate of 200L / min, and the methanol is introduced at a rate of 30mL / min.
[0020] The test block of the surface composite QPQ salt bath treatment test group is preheated to 200 DEG C. The preheated test block is placed in a nitriding salt bath pool at 530-590 DEG C, and is kept for 60-120 min. After the keeping, it is cooled to room temperature.
[0021] Step 3, determining the surface strengthening mode of the runner:
[0022] The surface hardness and friction and wear performance of each strengthened layer obtained by the surface nitriding treatment test, the nitrocarburizing treatment test and the surface composite QPQ salt bath treatment test in step 2 are tested respectively, and the following results are obtained: the surface hardness of the surface nitriding process is HV1075, the friction coefficient is 0.706, and the wear amount is 0.903 / 10 6 μm 3 ; the surface hardness of the nitrocarburizing process is HV1037, the friction coefficient is 0.713, and the wear amount is 3.002 / 10 6 μm 3 ; the surface hardness of the surface composite QPQ salt bath process is HV959, the friction coefficient is 0.749, and the wear amount is 0.557 / 10 6 μm 3 .
[0023] The surface hardness and friction and wear performance of each strengthened layer are comprehensively determined, and the surface composite QPQ salt bath method is determined as the surface strengthening mode of the runner.
[0024] Step 4, strengthening of the runner surface:
[0025] The surface composite QPQ salt bath process is used to strengthen the runner surface. Specifically
[0026] The surface composite QPQ salt bath process is used to strengthen the runner surface. Specifically
[0027] The surface composite QPQ salt bath process is used to strengthen the runner surface. Specifically
[0028] The technical problem solved by the application is that, by carrying out surface strengthening research on Cr12MoV material, the QPQ technology is used to strengthen the runner, the strengthened runner is applied to work under complex working conditions of high load, high wear resistance and contact fatigue resistance, and the strengthening effect is verified.
[0029] Table 1 Cr12MoV test block surface strengthening process test scheme
[0030] Group number Strengthening process Hardness to be achieved after strengthening 1 Surface nitriding ≥ HV 780 2 Nitrocarburizing ≥ HV 780 3 Surface composite QPQ salt bath treatment ≥ HV 780
[0031] Carrying out wear test experiment, respectively carrying out friction and wear test on the above 3 groups of test pieces on the friction and wear test machine, recording the wear amount and surface hardness of each group of test pieces with the increase of load size and wear time, selecting the optimal surface strengthening method, the test scheme is shown in table 2.
[0032] Table 2 wear amount comparison test scheme of Cr12MoV test block
[0033] Group number Wear time Wear amount 1 Surface nitriding 2 Nitrocarburizing 3 Surface composite QPQ salt bath treatment
[0034] Compared with the prior art, the beneficial effects obtained by the present application are:
[0035] The test pieces are respectively subjected to surface nitriding treatment, nitrocarburizing treatment and surface composite QPQ salt bath treatment, based on the research results of the process parameters of the three surface strengthening methods, see the attached Figure 3 -Appendix Figure 5 , the surface hardness and friction and wear performance of the test pieces under different surface strengthening systems are compared and analyzed. Through the analysis of the test data, it is concluded that the wear resistance after the surface composite QPQ salt bath treatment is the best, and the hardness meets the working requirements of the spinning wheel, and a surface strengthening method of the spinning wheel is determined.
[0036] The composite QPQ salt bath treatment is selected to strengthen the surface of the spinning wheel, see the attached Figure 6 The service life of the spinning wheel is verified on the spinning equipment, and it is confirmed that the service life of the spinning wheel after the composite QPQ salt bath treatment is improved by 10% compared with the spinning wheel without strengthening treatment. BRIEF DESCRIPTION OF DRAWINGS
[0037] Figure 1 is the force diagram of the spinning wheel and the workpiece in contact.
[0038] Figure 2 is the direct reflection of the spinning wheel defect on the surface of the product.
[0039] Figure 3 is the influence law of surface nitriding process parameters on the thickness of the nitriding layer; wherein, Figure 3 a is the influence of temperature on the thickness of the nitriding layer, Figure 3 b is the influence of time on the thickness of the nitriding layer.
[0040] Figure 4 is the influence law of nitrocarburizing process parameters on the thickness of the nitriding layer; wherein, Figure 4 a is the influence of co-diffusion time on the thickness of the nitriding layer, Figure 4 b is the influence of co-diffusion temperature on the thickness of the nitriding layer.
[0041] Figure 5 is the influence law of surface composite QPQ salt bath treatment process parameters on the thickness of the nitriding layer; wherein, Figure 5 a is the influence of temperature on the thickness of the nitriding layer,Figure 5 b is the effect of time on case depth.
[0042] Figure 6 is the surface nitriding process curve.
[0043] Figure 7 is the surface nitriding case scanning structure.
[0044] Figure 8 is the nitrocarburizing process curve.
[0045] Figure 9 is the nitrocarburized case scanning structure.
[0046] Figure 10 is the surface composite QPQ salt bath treatment process curve.
[0047] Figure 11 is the surface composite QPQ salt bath treated case scanning structure.
[0048] Figure 12 is the flow chart of the present application. DETAILED DESCRIPTION
[0049] Step 1, preparing test blocks:
[0050] The test blocks are made of Cr12MoV high-carbon die steel which is the same as the base material of the runner. The surface roughness of the test blocks is ≦Ra0.8.
[0051] The test blocks are divided into three test groups, i.e. the nitriding treatment test group, the nitrocarburizing treatment test group and the surface composite QPQ salt bath treatment test group.
[0052] Step 2, different nitriding treatment tests:
[0053] The test pieces are respectively subjected to surface nitriding treatment test, nitrocarburizing treatment test and surface composite QPQ salt bath treatment test by using conventional process. The runner surface strengthening process is determined through analysis of the test data.
[0054] The present application carries out nitriding treatment, nitrocarburizing treatment and surface composite QPQ salt bath treatment by using different process parameters, specifically:
[0055] I. Nitriding treatment test
[0056] The nitriding treatment test group is subjected to nitriding treatment by using conventional method. The process route of the surface nitriding treatment is preheating-heating-heat preservation-exhaust cooling, and the specific process is as follows:
[0057] The test pieces in the nitriding treatment group are heated to 520-550℃ by the heating furnace at a heating rate of 10-15℃ / min. Nitrogen is introduced when the test pieces are preheated to 200℃. The test pieces are kept at the temperature after being heated to 520-550℃. The keeping time is 30h. The surface nitriding process curve is shown in Fig. 1. After the keeping, the test pieces are cooled to room temperature in the furnace. A 9-12μm thick nitriding layer is obtained on the surface of the test pieces, which is the strengthening layer. Figure 7
[0058] In the nitriding treatment, the ammonia decomposition rate of the nitrogen is 30%-50%.
[0059] The nitriding layer is observed to be combined and compact by the scanning electron microscope picture as shown in Fig. 2. The bright white layer on the surface of the test piece is the strengthening layer. Figure 8
[0060] II Nitrocarburizing treatment
[0061] The nitrocarburizing process route is preheating-heating-keeping-venting and cooling. The specific process is as follows:
[0062] The test pieces in the nitrocarburizing treatment group are heated to 630-690℃ by the heating furnace at a heating rate of 10-15℃ / min. The test pieces are kept at the temperature after being heated to 630-690℃. The keeping time is 120-180min. The nitrocarburizing process curve is shown in Fig. 3. After the keeping, the test pieces are cooled to room temperature in the furnace. A 5-6μm thick nitriding layer is obtained on the surface of the test pieces, which is the strengthening layer. Figure 9
[0063] In the nitrocarburizing treatment, the ammonia gas is introduced at a rate of 200L / min and the methanol is introduced at a rate of 30mL / min.
[0064] The nitriding layer is observed to be combined and compact by the scanning electron microscope picture as shown in Fig. 4. The bright white layer on the surface of the test piece is the strengthening layer. Figure 10 III Surface composite QPQ salt bath treatment
[0065] The test pieces in the surface composite QPQ salt bath treatment group are treated by the surface composite QPQ salt bath treatment by using the conventional process. The surface composite QPQ salt bath treatment process route is preheating-heating-salt bath keeping-venting and cooling. The specific process is as follows:
[0066] The test pieces are preheated to 200℃. The preheated test pieces are put into a 530-590℃ nitriding salt bath pool for keeping for 60-120min. The surface composite QPQ salt bath treatment process curve is shown in Fig. 5. After the keeping, the test pieces are cooled to room temperature. A 5-8μm thick nitriding layer is obtained, which is the strengthening layer.
[0067] Figure 11
[0068] The penetration layer is combined and dense by scanning electron microscope, as shown in the figure. The bright white layer on the surface of the test block is the strengthened layer. Figure 12
[0069] Table 3 Process parameters of each example in step 2
[0070]
[0071]
[0072] Step 3, determining the best surface strengthening method:
[0073] According to the conventional method, the surface hardness and friction and wear performance of the strengthened layer obtained by different processes in step 2 are tested, respectively. The surface hardness of the surface nitriding process is HV1075, the friction coefficient is 0.706, and the wear amount is 0.903 / 10 6 μm 3 ; the surface hardness of the nitrocarburizing process is HV1037, the friction coefficient is 0.713, and the wear amount is 3.002 / 10 6 μm 3 ; the surface hardness of the surface composite QPQ salt bath process is HV959, the friction coefficient is 0.749, and the wear amount is 0.557 / 10 6 μm 3 .
[0074] The test results show that the surface nitriding process, the nitrocarburizing process and the surface composite QPQ salt bath process meet the hardness requirements of the runner.
[0075] The wear performance analysis results show that the wear resistance of the surface composite QPQ salt bath process is the best, followed by the surface nitriding, and the wear resistance of the nitrocarburizing is poor.
[0076] The surface hardness and friction and wear performance of each strengthened layer show that the comprehensive performance of the surface composite QPQ salt bath process is the best.
[0077] Table 4 Surface hardness of test sample penetration layer under different process conditions
[0078] Group number Strengthening process Hardness achieved after strengthening 1 Surface nitriding HV 1075 2 Nitrocarburizing HV 1037 3 QPQ technology HV 959
[0079] Table 5 Friction and wear performance of test sample under different process conditions
[0080] Group number Wear time Friction coefficient wear amount ( / 10 6 μm 3 )]]> 1 Surface nitriding 0.706 0.903 2 Nitrocarburizing 0.713 3.002 3 QPQ technology 0.749 0.577
[0081] Step 4, strengthening the surface of the runner:
[0082] The surface of the runner is strengthened by the surface composite QPQ salt bath process. Specifically
[0083] According to the surface composite QPQ salt bath treatment process described in step 2, the surface of the spinning wheel is surface composite QPQ salt bath treated by using a conventional process.
[0084] The surface composite QPQ salt bath treatment process route is preheating-heating-salt bath holding-degassing cooling, and the specific process is as follows:
[0085] Each test block is preheated to 200℃. The preheated test block is placed in a nitriding salt bath pool at 530-590℃, and is held for 60-120min. After holding, it is cooled to room temperature to obtain a 5-8μm thick infiltration layer, i.e. a strengthening layer. A spinning wheel with a surface subjected to strengthening treatment is obtained.
[0086] To verify the effect of the application, the spinning wheel with a surface subjected to strengthening treatment is tested. The test results prove that the spinning wheel with the surface subjected to strengthening treatment has a coating peeling off after being machined to 220 workpieces, and the service life is increased by 10% compared with the spinning wheel without the surface subjected to strengthening treatment.
[0087] Table 6 Machining quantity and spinning wheel surface hardness relationship
[0088]
[0089] Table 7 Machining quantity and spinning wheel fillet wear amount relationship
[0090]
Claims
1. A method of determining a spin wheel surface enhancement process, characterized by, The specific process is: Step 1, preparing test blocks: The test blocks are divided into three test groups, namely, a nitriding treatment test group, a nitrocarburizing treatment test group and a surface composite QPQ salt bath treatment test group; Step 2, different nitriding treatment tests: The test blocks in the nitriding treatment test group, the test blocks in the nitrocarburizing treatment test group and the test blocks in the surface composite QPQ salt bath treatment test group are respectively subjected to surface nitriding treatment test, nitrocarburizing treatment test and surface composite QPQ salt bath treatment test; through analysis of the test data, the surface strengthening process of the runner is determined; The test blocks in the nitriding treatment test group are subjected to nitriding treatment; the process route of the surface nitriding treatment is preheating-heating-heat preservation-exhaust cooling, and a strengthened layer with a thickness of 9-12 μm is obtained; The process route of the nitrocarburizing treatment is preheating-heating-heat preservation-exhaust cooling; the nitriding layer is the strengthened layer of the test blocks; The process route of the surface composite QPQ salt bath treatment is preheating-heating-salt bath heat preservation-exhaust cooling; A strengthened layer with a thickness of 5-8 μm is obtained; The process of the surface nitriding treatment test of the test blocks in the nitriding treatment test group is that the test blocks in the nitriding treatment test group are heated to 520-550 ℃ at a heating rate of 10-15 ℃ / min through a heating furnace; During the heating process, nitrogen is introduced when the test blocks are preheated to 200 ℃; heat preservation is started when the test blocks are heated to 520-550 ℃; the heat preservation time is 30 h; after the heat preservation is completed, the test blocks are cooled to room temperature in the furnace; In the nitriding treatment, the ammonia decomposition rate of the nitrogen is 30%-50%; The process of the surface nitrocarburizing treatment test of the test blocks in the nitrocarburizing treatment test group is that the test blocks in the nitrocarburizing treatment test group are heated to 630-690 ℃ at a heating rate of 10-15 ℃ / min through a heating furnace; heat preservation is started when the test blocks are heated to 630-690 ℃; the heat preservation time is 120-180 min; after the heat preservation is completed, the test blocks are cooled to room temperature in the furnace, and a nitriding layer with a thickness of 5-6 μm is obtained on the surface of the test blocks; In the nitrocarburizing treatment, the ammonia introduction amount is 200 L / min, and the methanol introduction amount is 30 mL / min; In the surface composite QPQ salt bath treatment, the test blocks in the surface composite QPQ salt bath treatment test group are preheated to 200 ℃; the preheated test blocks are placed in a nitriding salt bath pool at 530-590 ℃, and heat preservation is performed for 60-120 min; after the heat preservation is completed, the test blocks are cooled to room temperature; Step 3, determining the surface strengthening method of the runner: The surface hardness and friction and wear properties of each strengthened layer obtained by the surface nitriding treatment, the nitrocarburizing treatment and the surface composite QPQ salt bath treatment in step 2 are tested respectively, and it is obtained that the surface hardness of the surface nitriding process is HV1075, the friction coefficient is 0.706, the wear amount is 0.903 / 10 6 μm 3 ; the surface hardness of the nitrocarburizing process is HV1037, the friction coefficient is 0.713, the wear amount is 3.002 / 10 6 μm 3 ; the surface hardness of the surface composite QPQ salt bath process is HV959, the friction coefficient is 0.749, the wear amount is 0.557 / 10 6 μm 3 ; The surface composite QPQ salt bath method is determined as the surface strengthening method of the runner by comprehensively considering the surface hardness and friction and wear properties of the strengthened layers; Step 4, strengthening the surface of the runner: The surface of the runner is strengthened by using the surface composite QPQ salt bath process; Specifically: The surface of the runner is subjected to surface composite QPQ salt bath treatment according to the process of the surface composite QPQ salt bath treatment described in step 2; and a runner with a surface subjected to strengthening treatment is obtained.
2. The method of determining a superfinishing process of a raceway surface as recited in claim 1, wherein, The material of the test blocks is the same as that of the runner body; the surface roughness of the test blocks is ≤Ra 0.8.