Ultrasonic rolling composite lubricating treatment method for drawing die
By using an ultrasonic rolling composite lubrication treatment method, combined with ultrasonic rolling equipment and a new type of lubricating grease, the problem of insufficient lubrication and damage to stretching dies under high speed and high pressure was solved. This improved the hardness and smoothness of the die surface and enhanced the lubrication effect, ensuring processing quality and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-12-09
- Publication Date
- 2026-03-13
AI Technical Summary
Traditional stretching dies are prone to scratches, adhesion, and cracking during use, and the lubrication is insufficient under single ultrasonic rolling treatment, which cannot meet the requirements of high-speed and high-pressure stretching conditions.
An ultrasonic rolling composite lubrication treatment method is adopted, which includes mold pretreatment, ultrasonic rolling, grease coating and stretching. By combining ultrasonic rolling equipment with a new type of low-friction, high-temperature resistant grease, the surface performance and lubrication effect of the mold are improved.
It improves the surface hardness and smoothness of the mold, ensures long-term friction reduction and wear resistance during the stretching process, solves the mold damage problem caused by traditional lubrication methods, and meets the needs of long-term continuous stretching processing.
Smart Images
Figure CN121649288A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of mold surface treatment technology, and in particular to a method for ultrasonic rolling composite lubrication treatment of stretching dies. Background Technology
[0002] Drawing dies are widely used in parts forming and processing, and their surface properties directly affect the workpiece processing quality and die life. Traditional drawing dies usually use a single lubricant or a coated lubrication method. During long-term use, the die surface is prone to problems such as scratches, adhesion, and cracking, which leads to accelerated die failure, reduced workpiece surface quality, and seriously affects production efficiency and product qualification rate.
[0003] Ultrasonic rolling, as a surface modification process, uses the synergistic effect of static rolling and high-frequency ultrasonic vibration to induce plastic deformation on the workpiece surface, achieving grain refinement and roughness reduction. However, molds treated with ultrasonic rolling alone still suffer from insufficient lubrication under high-speed, high-pressure tensile conditions; while traditional greases are difficult to adapt to the special morphology of the mold surface after ultrasonic rolling, and have limited high-temperature resistance and friction-reducing properties. Therefore, there is an urgent need to develop a composite treatment technology that combines ultrasonic rolling with specialized greases to synergistically improve mold surface properties and lubrication effects. Summary of the Invention
[0004] The purpose of this invention is to address the shortcomings of the prior art by proposing a method for ultrasonic rolling composite lubrication treatment of stretching dies.
[0005] To achieve the above objectives, the technical solution adopted by this invention is: a method for ultrasonic rolling composite lubrication treatment of stretching dies, comprising the following steps:
[0006] Step 1: Mold pretreatment: Select a drawing die made of mold steel, clean its surface to remove surface oil, oxide scale and impurities, and ensure that the original roughness of the mold surface to be treated is 0.4-0.6μm;
[0007] Step 2: Ultrasonic rolling treatment: The stretching die is clamped on a CNC lathe and rolled using an ultrasonic rolling device. The hardened cutting head of the ultrasonic rolling device presses the die surface at a feed speed of 50-100 mm / min, accompanied by a static pressure of 400 N and an ultrasonic power of 200 W, and rolls back and forth 3 times along the surface of the die to be treated.
[0008] Step 3: Grease Coating: After the mold has cooled to 20-25℃ after ultrasonic rolling, a new type of low-friction, high-temperature resistant grease is applied to its working surface; the grease includes base oil, thickener and additives;
[0009] Step 4: Stretching process application: The grease-coated stretching die is installed on the die holder of a high-performance hydraulic press for stretching and forming.
[0010] Preferably, the ultrasonic rolling equipment described in step two is compatible with the CKD6140i CNC lathe. During the rolling process, the hardened cutting head extrudes and stretches the surface of the mold at a set feed speed, accompanied by high-frequency ultrasonic vibration.
[0011] Preferably, when applying the grease, a rubber blade is used to remove the excess portion, ensuring that only a thin, uniform grease film remains on the surface of the stretching die, with the film thickness controlled at 5-10 μm.
[0012] Preferably, the base oil is a mixture of mineral oil and polyalphaolefin at a mass ratio of 1:2, and has a kinematic viscosity of 68 cst at 40°C. The thickener is polyurea, and the thickener accounts for 8-12% of the total mass of the grease. The additive is molybdenum dialkyl dithiophosphate, and the additive accounts for 1.5-2.5% of the total mass of the grease.
[0013] Preferably, the grease has a cone penetration of 260 (0.1 mm) at 25°C.
[0014] Preferably, in step four, the coaxiality deviation of the mold base is ≤0.03mm, and the hydraulic press is started for stretching and forming.
[0015] Preferably, the hydraulic press controls the stretching process parameters as follows: stretching force 50-200kN, stretching speed 5-20mm / min, stretching stroke accuracy ±0.05mm, and real-time monitoring of stretching force fluctuation ≤±5%, stretching speed fluctuation ≤±3%, and mold working temperature ≤80℃ during the stretching process.
[0016] Preferably, after stretching and forming in step four, the workpiece is inspected for dimensional accuracy and surface quality to ensure that the processing quality meets the standards.
[0017] Compared with the prior art, the present invention has the following beneficial effects:
[0018] This invention can improve the surface hardness and smoothness of stretching dies through ultrasonic rolling treatment, and achieve long-term friction reduction and wear resistance during the stretching process through special grease coating. At the same time, it can ensure process stability through full-process monitoring. It solves the problems in the prior art where traditional lubrication methods are prone to causing scratches, adhesion, and cracking on the surface of stretching dies, or where single ultrasonic rolling treatment lacks suitable lubrication and cannot meet the needs of long-term continuous stretching processing. Attached Figure Description
[0019] Figure 1 A comparison of the surface roughness reduction of each group in the orthogonal experiment of ultrasonic rolling parameters; Figure 2Comparison of surface morphology and three-dimensional morphology of No. 5 mold steel before and after ultrasonic rolling;
[0020] Figure 3 Comparison of microhardness of specimens in different groups after ultrasonic rolling;
[0021] Figure 4 Curves of friction coefficients of specimens under different ultrasonic rolling parameters;
[0022] Figure 5 This is a comparison diagram of the wear volume of each group of specimens after ultrasonic rolling;
[0023] Figure 6 The wear morphology, three-dimensional morphology and cross-sectional view of some groups of specimens are shown.
[0024] Figure 7 The wear morphology, three-dimensional morphology, and cross-sectional views of another group of specimens are shown.
[0025] Figure 8 This is a diagram showing the main effects of friction performance analysis.
[0026] Figure 9 Comparison of friction and wear of samples #5 and #9 under dry friction and grease lubrication;
[0027] Figure 10 Comparison of wear morphology of samples #5 and #9 under dry friction and grease lubrication;
[0028] Figure 11 This is a comparison image of the surface state of the mold after treatment by the method of the present invention and that of the untreated mold;
[0029] Figure 12 These are the parameters for ultrasonic rolling. Detailed Implementation
[0030] The following description is intended to disclose the invention and enable those skilled in the art to implement it. The preferred embodiments described below are merely examples, and other obvious variations will occur to those skilled in the art.
[0031] like Figures 1-12 The method for ultrasonic rolling composite lubrication treatment of stretching dies, as shown, includes the following steps:
[0032] Step 1: Mold pretreatment: Select a drawing die made of mold steel, clean its surface to remove surface oil, oxide scale and impurities, and ensure that the original roughness of the mold surface to be treated is 0.4-0.6μm;
[0033] Step 2: Ultrasonic rolling treatment: The stretching die is clamped on a CNC lathe and rolled using an ultrasonic rolling machine. The hardened cutting head of the ultrasonic rolling machine presses the die surface at a feed speed of 50-100 mm / min, accompanied by a static pressure of 400 N and an ultrasonic power of 200 W. The die is rolled back and forth 3 times along the surface to be treated.
[0034] Step 3: Grease application: After the mold has cooled to 20-25℃ after ultrasonic rolling, apply a new type of low-friction, high-temperature resistant grease to its working surface; the grease includes base oil, thickener and additives;
[0035] Step 4: Stretching process application: The grease-coated stretching die is installed on the die holder of a high-performance hydraulic press for stretching and forming.
[0036] In step two, the ultrasonic rolling equipment is adapted to the CKD6140i CNC lathe. During the rolling process, the hardened cutting head extrudes and stretches the mold surface at a set feed speed, accompanied by high-frequency ultrasonic vibration.
[0037] When applying grease, use a rubber blade to remove excess grease, ensuring that only a thin, uniform grease film remains on the surface of the stretching die, with the film thickness controlled at 5-10 μm.
[0038] The base oil is made by mixing mineral oil and polyalphaolefin in a mass ratio of 1:2, and has a kinematic viscosity of 68 cst at 40°C. The thickener is polyurea, and the thickener accounts for 8-12% of the total mass of the grease. The additive is molybdenum dialkyl dithiophosphate, and the additive accounts for 1.5-2.5% of the total mass of the grease.
[0039] The grease has a cone penetration of 260 (0.1 mm) at 25°C.
[0040] In step four, if the coaxiality deviation of the mold base is ≤0.03mm, start the hydraulic press for stretching and forming.
[0041] The hydraulic press controls the stretching process parameters as follows: stretching force 50-200kN, stretching speed 5-20mm / min, stretching stroke accuracy ±0.05mm, and real-time monitoring of stretching force fluctuation ≤±5%, stretching speed fluctuation ≤±3%, and mold working temperature ≤80℃ during the stretching process.
[0042] After stretching and forming in step four, the workpiece is inspected for dimensional accuracy and surface quality to ensure that the processing quality meets the standards.
[0043] The above method can be implemented using the following process system, which includes a mold pretreatment system, an ultrasonic rolling system, a grease coating system, and a stretching application and monitoring system. The mold pretreatment system includes: mold surface cleaning tools (degreaser, high-pressure air gun) and a surface roughness testing instrument. The mold pretreatment system is mainly used to ensure that the mold surface condition meets the standards before ultrasonic rolling, laying the foundation for subsequent processing. The degreaser, used in conjunction with the high-pressure air gun, removes oil, scale, and impurities from the mold surface, preventing contaminants from affecting the rolling effect. The surface roughness testing instrument is used to measure the original roughness of the mold surface to be treated, ensuring it is controlled within the range of 0.4-0.6 μm, meeting the initial surface requirements of the ultrasonic rolling process.
[0044] The ultrasonic rolling system includes: a CKD6140i CNC lathe, an ultrasonic rolling device (including a hardened cutting head), an ultrasonic rolling parameter control system, and a die clamping structure. The ultrasonic rolling system is mainly used for surface plastic deformation treatment of stretching dies made of die steel, achieving grain refinement, roughness reduction, and hardness improvement. The CKD6140i CNC lathe provides a stable processing platform for ultrasonic rolling, ensuring coaxiality and processing accuracy after die clamping. The hardened cutting head of the ultrasonic rolling device presses the die surface at a feed speed of 50-100 mm / min, accompanied by high-frequency ultrasonic vibration. The surface modification of the die is achieved through the synergistic effect of static rolling and ultrasonic vibration. The ultrasonic rolling parameter control system is used to set and lock the optimal process parameters (static pressure 400 N, ultrasonic power 200 W, reciprocating rolling times 3 times) to avoid parameter fluctuations during processing. The die clamping structure is used to fix the stretching die, ensuring no displacement of the die during rolling and guaranteeing uniform surface treatment.
[0045] The grease coating system includes: a novel low-friction, high-temperature resistant grease, a rubber blade, and a grease film thickness detection tool. The grease coating system is mainly used to form a uniform and stable protective lubricating film on the surface of the mold after ultrasonic rolling, improving the friction reduction and anti-wear performance during the mold stretching process. The novel low-friction, high-temperature resistant grease is composed of base oil (mineral oil and polyalphaolefin mixed at a mass ratio of 1:2, kinematic viscosity 68 cst at 40℃), thickener (polyurea, accounting for 8-12% of the total grease mass), and additive (molybdenum dialkyl dithiophosphate MoDDP, accounting for 1.5-2.5% of the total grease mass), and has a cone penetration of 260 (0.1 mm) at 25℃, exhibiting excellent high-temperature resistance and friction reduction performance. The rubber blade is used to scrape the grease along the surface texture of the mold, removing excess grease to control the lubricating film thickness (5-10 μm) and avoid uneven film thickness affecting the lubrication effect. The grease film thickness detection tool is used to verify the film thickness in real time to ensure that the coating quality meets the standards.
[0046] The stretching processing application and monitoring system includes: a high-performance hydraulic press (including a die holder and a coaxiality adjustment structure), a stretching parameter control system (tensioning force, speed, and stroke adjustment modules), a real-time monitoring module (force sensor, speed sensor, and temperature sensor), and workpiece quality inspection equipment (dimensional accuracy gauges and surface roughness testers). The system is primarily used to realize the actual stretching application of the treated die and ensure process stability and workpiece quality compliance. The die holder of the high-performance hydraulic press is used to install the composite-treated stretching die, and the coaxiality adjustment structure can control the coaxiality deviation of the die to ≤0.03mm, avoiding eccentric stretching. Die damage; The stretching parameter control system is used to set the stretching process parameters (stretching force 50-200kN, stretching speed 5-20mm / min, stretching stroke accuracy ±0.05mm) and synchronously control the hydraulic press to execute; The real-time monitoring module monitors the stretching force fluctuation value (≤±5%), stretching speed fluctuation value (≤±3%), and die working temperature (≤80℃) through force sensors, speed sensors, and temperature sensors respectively to ensure the stability of processing parameters; The workpiece quality inspection equipment is used to inspect the workpiece dimensional accuracy (tolerance grade IT8-IT10) and surface roughness (Ra≤1.6μm) after stretching and forming to verify the die processing effect.
[0047] When using this process system, the stretching die is first cleaned using a die pretreatment system to remove surface oil and impurities, and its original surface roughness is checked and ensured to be 0.4-0.6μm. Then, the pretreated die is clamped onto the die clamping structure of a CKD6140i CNC lathe. The ultrasonic rolling parameter control system is used to set the process parameters to 400N static pressure, 200W power, and 3 rolling cycles. The ultrasonic rolling equipment is then started, and a hardened cutting head performs rolling treatment along the die surface. After the die cools to 20-25℃, a new type of low-friction, high-temperature resistant grease is applied to the die's working surface using a rubber blade. Excess grease is scraped off, and the grease film thickness is checked using a film thickness detection tool to ensure it is 5-10μm thick. Finally, the grease-coated die is installed on the die holder of a high-performance hydraulic press. The coaxiality deviation is adjusted to ≤0.03mm. The stretching process parameters are set using the stretching parameter control system, the hydraulic press is started, and the processing is monitored by a real-time monitoring module. After stretching, the workpiece dimensions and surface quality are verified using a workpiece quality inspection device.
[0048] The following is an example illustrating the specific steps of this method:
[0049] Example 1: Orthogonal Experiment of Ultrasonic Rolling Process
[0050] Experimental materials: Mold steel specimens with a surface roughness of approximately 0.5 μm were selected and machined into square specimens with a side length of 25 mm;
[0051] Experimental equipment: CKD6140i CNC lathe, ultrasonic rolling equipment, UMT-2 ball-and-plate friction and wear testing machine, white light interferometer;
[0052] Orthogonal experimental design: Three factors were set (static pressure: 400N, 600N, 800N; power: 200W, 400W, 600W; rolling cycles: 1, 3, 5), resulting in a total of 9 sets of process parameters (e.g., ...). Figure 12 (as shown)
[0053] Experimental procedure: The specimens were subjected to ultrasonic rolling treatment according to the parameters of each group, followed by friction and wear test (ambient temperature 25℃, load 100N, stroke 5mm, reciprocating frequency 5Hz, friction time 3600s). The surface roughness, wear morphology and wear mark size were detected by white light interferometer.
[0054] Results Analysis: Main effect analysis showed that static pressure had the most significant impact on the friction coefficient and wear amount. Specimen #5 exhibited the largest decrease in surface roughness and the smallest wear volume. Figure 1 As shown. Figure 2 As shown, a and c are the unrolled parts of part #5, and b and d are the rolled parts of part #5. It can be seen that the surface quality of the workpiece is significantly improved after ultrasonic rolling treatment. Figure 3 The figures show the microhardness values of nine mold steel samples. 10# is a control sample without ultrasonic rolling. It can be seen that the hardness of the mold steel improved after ultrasonic rolling, with sample 9# showing the greatest increase in hardness. Figure 4 The friction coefficient curves of the steel disc surfaces are shown, where #1-9 represent the friction coefficient curves of ultrasonically rolled steel discs, and #10 represents the friction coefficient curve of unrolled steel discs. It can be seen that there is a trend of first increasing and then decreasing throughout the entire process. For #1, #2, #3, #4, #5, #6, #7, #8, and #10, after different running-in times, the friction coefficient eventually decreases to a constant value. This behavior is attributed to the protective lubricating film formed by friction. However, the friction coefficient curve of #4 fluctuates at 3100s, indicating that the lubricating film has been damaged.
[0055] For #1, #2, #3, #5, #6, #7, #8, and #9, the friction pairs begin to contact within 0-70 seconds. The protrusions on the friction surfaces collide with each other, causing a significant increase in the coefficient of friction (COF). During the subsequent break-in process, the COF gradually decreases and stabilizes at around 0.09, indicating that a lubricating film forms on the friction pair surface and remains stable during subsequent friction. The friction coefficients of #2, #5, and #6 reach their lowest point at 400s and 500s and then remain stable. The friction coefficients of #1, #3, #7, and #9 reach their lowest point at 1200s and 1400s and then stabilize, while the friction coefficient of #8 reaches its lowest point at 2700s and then stabilizes. For #4, the friction pairs begin to contact within 0-40 seconds, and the protrusions on the friction pairs collide with each other, causing a significant increase in the friction coefficient. However, this increase does not stabilize during subsequent friction and exhibits some fluctuations. The friction coefficient of #4 stabilized after 1500s, but then fluctuated drastically after 3100s, indicating that the lubricating film was damaged. This fluctuation is likely due to wear debris generated during the test damaging the lubricating film, causing the friction coefficient to suddenly increase after its initial decrease.
[0056] from Figure 4 As can be seen, the friction coefficient of the steel disc stabilized rapidly after ultrasonic rolling, without a significant decrease. When the friction coefficient quickly reaches a stable state, it means that the interaction force between the contact surfaces also tends to stabilize, reducing additional wear caused by fluctuations in the friction coefficient and thus reducing friction. This indicates that ultrasonic rolling can improve the surface properties of the steel disc, rapidly stabilize the friction coefficient, and increase the disc's wear-reducing ability.
[0057] Figure 5 The bar chart shows the wear volume of the mold steel disc, where #1-9 represent the wear volume of the steel disc under different ultrasonic rolling parameters, and #10 represents the wear volume of the steel disc without ultrasonic rolling. Compared with #10, the wear volume of the steel discs after ultrasonic rolling is reduced. The largest reductions are seen in #2, #5, and #6, at 74.65%, 74.68%, and 73.18% respectively, while the smallest reductions are seen in #1, #3, and #8, within 20%-30%. This indicates that ultrasonic rolling can improve the surface properties of the steel disc, reduce its wear rate, and increase its wear resistance. Figure 6 and Figure 7 This indicates the wear morphology of the steel discs for molds #1-#10, and... Figure 5 The results were consistent.
[0058] Example 2: Optimization of Ultrasonic Rolling Process
[0059] Process parameters and evaluation indicators: Independent variables: static pressure (unit: N), ultrasonic power (unit: W), number of rolling cycles (unit: times);
[0060] Evaluation indicators: average friction coefficient of the steel disc, cumulative wear amount (unit: mg);
[0061] Main effects analysis diagram: Figure 8 This is a main effect analysis diagram of the influence of the above three parameters on friction performance, where... Figure 8 (a) The influence law of the corresponding average friction coefficient, Figure 8 (b) The influence of wear amount.
[0062] The influence of process parameters on wear: Figure 8 (a) shows the main effect analysis results, and the order of significance of the three process parameters on the average friction coefficient of the steel disc is: static pressure > ultrasonic power ≈ number of rolling cycles. The influence law and mechanism of each parameter are as follows: (1) Static pressure and ultrasonic power: With the increase of static pressure or ultrasonic power, the average friction coefficient of the steel disc shows a trend of "first decreasing and then increasing". The core mechanism is that the static pressure and ultrasonic power jointly determine the actual rolling pressure during the ultrasonic rolling process. When the rolling pressure is small, the grinding marks on the surface of the steel disc cannot be effectively flattened, the surface roughness is high, and the friction coefficient is large. When the rolling pressure gradually increases to a suitable range, the grinding marks are completely flattened, the surface flatness is improved, and the friction coefficient is reduced to the minimum. When the rolling pressure exceeds the yield strength limit of the steel disc, uneven plastic deformation occurs in the rolling area, the surface morphology deteriorates, and the average friction coefficient increases. (2) Number of rolling cycles: With the increase of the number of rolling cycles, the average friction coefficient of the steel disc shows a continuous decreasing trend.
[0063] The influence of process parameters on wear: Figure 8(b) shows the main effect analysis results, and the order of significance of the three process parameters on the wear of the steel disc is: static pressure > ultrasonic power > rolling times. The influence law and mechanism of each parameter are as follows: (1) Static pressure: As the static pressure increases, the wear of the steel disc shows a trend of "first decreasing and then increasing". The core mechanism is that when the static pressure is small, the grain refinement of the workpiece surface is insufficient, the work hardening effect is not obvious, the surface hardness is low, resulting in a large wear; as the static pressure increases to a suitable range, the grain refinement and grain boundary dislocation entanglement effect are enhanced, the surface deformation resistance is improved, and the wear is significantly reduced; when the static pressure exceeds the yield strength limit of the steel disc, the workpiece surface produces uneven plastic deformation, and even surface cracks and other damage, resulting in a further increase in wear. (2) Ultrasonic power and rolling times: As the ultrasonic power or rolling times increase, the wear of the steel disc shows a continuous decreasing trend. Its mechanism of action is as follows: increasing the ultrasonic power can enhance the impact and plastic deformation effect of ultrasonic vibration on the workpiece surface, and increasing the number of rolling cycles can accumulate the surface work hardening effect. Both can promote the refinement of grains and the entanglement of grain boundary dislocations on the workpiece surface, improve the degree of surface work hardening, and thus enhance the surface wear resistance and reduce the amount of wear.
[0064] Determination of optimal ultrasonic rolling process parameters: combined with Figure 8 (a) and Figure 8 Based on the main effect analysis results in (b), and considering the dual objectives of minimizing the average friction coefficient and minimizing wear, the optimal combination of process parameters for ultrasonic rolling of the steel disc in this embodiment is determined as follows:
[0065] Static pressure: 400N, ultrasonic power: 200W, rolling cycles: 3 times.
[0066] By using the above-mentioned optimal process parameters for ultrasonic rolling, the steel disc can obtain the best friction performance, namely a lower average coefficient of friction and a minimum amount of wear, thus meeting the requirements for high wear resistance.
[0067] Example 3: Performance Test of Novel Lubricating Grease
[0068] Grease preparation: Mineral oil and polyalphaolefin (1:2) are mixed in proportion as base oil, polyurea thickener and MoDDP additive are added, stirred evenly, and the cone penetration is adjusted to 260 (0.1 mm).
[0069] Comparative experiment: The specimen (5#) after optimal parameter treatment in Example 1 and the specimen (9#) with the greatest increase in hardness were selected and subjected to friction and wear tests with dry friction and coating with new grease, respectively.
[0070] Result: As Figure 9 , Figure 10As shown, after coating with the new grease, the wear volume of the specimen decreased by 66%, the coefficient of friction stabilized at around 0.09, and the lubricating film did not rupture during the entire test, demonstrating significant friction reduction and anti-wear effects.
[0071] Example 4: Practical Application Verification of Composite Technology
[0072] Die processing: Select a stretching die (made of die steel), and perform ultrasonic rolling and grease coating according to the method of this invention;
[0073] Tensile test: The treated mold is installed on a high-performance hydraulic press. Key parameters such as tensile speed and pressure are controlled and monitored in real time during the processing of the parts.
[0074] Comparative test: such as Figure 11 As shown, compared with a mold without any surface treatment, after the same stretching process, the untreated mold surface showed obvious cracks and large-area scratches, while the mold surface treated by the present invention had no scratches or cracks, and the workpiece dimensional accuracy and surface quality met the requirements.
[0075] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention. The scope of protection claimed by the appended claims and their equivalents is defined.
Claims
1. A method for ultrasonic rolling composite lubrication treatment of stretching dies, characterized in that: Includes the following steps: Step 1: Mold pretreatment: Select a drawing die made of mold steel, clean its surface to remove surface oil, oxide scale and impurities, and ensure that the original roughness of the mold surface to be treated is 0.4-0.6μm; Step 2: Ultrasonic rolling treatment: The stretching die is clamped on a CNC lathe and rolled using an ultrasonic rolling device. The hardened cutting head of the ultrasonic rolling device presses the die surface at a feed speed of 50-100 mm / min, accompanied by a static pressure of 400 N and an ultrasonic power of 200 W, and rolls back and forth 3 times along the surface of the die to be treated. Step 3: Grease Coating: After the mold has cooled to 20-25℃ after ultrasonic rolling, a new type of low-friction, high-temperature resistant grease is applied to its working surface; the grease includes base oil, thickener and additives; Step 4: Stretching process application: The grease-coated stretching die is installed on the die holder of a high-performance hydraulic press for stretching and forming.
2. The ultrasonic rolling composite lubrication treatment method for stretching dies according to claim 1, characterized in that: The ultrasonic rolling equipment described in step two is compatible with the CKD6140i CNC lathe. During the rolling process, the hardened cutting head extrudes and stretches the surface of the mold at a set feed speed, accompanied by high-frequency ultrasonic vibration.
3. The ultrasonic rolling composite lubrication treatment method for stretching dies according to claim 1, characterized in that: When applying the grease, a rubber blade is used to remove the excess, ensuring that only a thin, uniform grease film remains on the surface of the stretching die, with the film thickness controlled at 5-10 μm.
4. The ultrasonic rolling composite lubrication treatment method for stretching dies according to claim 1, characterized in that: The base oil is a mixture of mineral oil and polyalphaolefin at a mass ratio of 1:2, and has a kinematic viscosity of 68 cst at 40°C. The thickener is polyurea, and the thickener accounts for 8-12% of the total mass of the grease. The additive is molybdenum dialkyl dithiophosphate, and the additive accounts for 1.5-2.5% of the total mass of the grease.
5. The ultrasonic rolling composite lubrication treatment method for stretching dies according to claim 1, characterized in that: The grease has a cone penetration of 260 (0.1 mm) at 25°C.
6. The method for ultrasonic rolling composite lubrication treatment of stretching dies according to claim 1, characterized in that: If the coaxiality deviation of the mold base in step four is ≤0.03mm, start the hydraulic press for stretching and forming.
7. The ultrasonic rolling composite lubrication treatment method for stretching dies according to claim 6, characterized in that: The hydraulic press controls the stretching process parameters as follows: stretching force 50-200kN, stretching speed 5-20mm / min, stretching stroke accuracy ±0.05mm, and real-time monitoring of stretching force fluctuation ≤±5%, stretching speed fluctuation ≤±3%, and mold working temperature ≤80℃ during the stretching process.
8. The method for ultrasonic rolling composite lubrication treatment of stretching dies according to claim 1, characterized in that: After stretching and forming in step four, the workpiece is inspected for dimensional accuracy and surface quality to ensure that the processing quality meets the standards.