Process for passivating cutting edge of hard alloy milling cutter

Abstract

The invention is suitable for the technical field of milling cutter machining, and provides a hard alloy milling cutter cutting edge passivation process which comprises the following steps that a passivation solution containing Fe < 3 + > and Zn < 2 + > is prepared, and the passivation solution comprises abrasive particles and a nanometer reinforcing phase; the tool is immersed in a passivation solution to be subjected to chemical-mechanical composite treatment; the cutting edge is subjected to plasma impact treatment; a cutting edge grain boundary is reconstructed through laser irradiation, and atomic-scale reconstruction of the hard alloy cutting edge and multi-scale optimization of structure strengthening are achieved through combination of a chemical-mechanical-energy field composite effect, a metal ion passivation reaction and plasma / laser modification and cooperation of metal ion selective passivation, grain boundary engineering regulation and control and nanometer enhancement. On the basis of chemical passivation, the mechanical performance of the cutting edge of the milling cutter is improved through a composite passivation film generated through Fe < 3 + > / Zn < 2 + > reaction, plasma impact and laser reconstruction are coupled through an energy field, the problems of microdefects and grain boundary weakening are solved respectively, and the strength of the cutting edge is further improved through the synergistic effect of the three.

Description

Technical Field

[0001] The present invention belongs to the technical field of milling cutter processing, and particularly relates to a passivation process for the cutting edge of a cemented carbide milling cutter. Background Art

[0002] Cemented carbide tools are widely used in precision machining fields such as aerospace and automotive manufacturing due to their high hardness, high temperature resistance, and excellent wear resistance. However, after grinding, there are defects such as microscopic burrs and cracks on the cutting edge of the tool, resulting in stress concentration and an increased chipping rate during the cutting process, seriously affecting the tool life and machining quality. Therefore, tool passivation treatment has become a key process to improve performance, but the existing technologies still have the following bottlenecks: Traditional mechanical passivation (such as vibration passivation, media passivation, sandblasting passivation) mainly relies on the physical impact of abrasives on the cutting edge to remove burrs. For example, the tool passivation machine disclosed in CN2015108347221 drives the tool to rotate in the abrasive through a rotating shaft, which has problems such as large insertion resistance of the tool and the need for a high-power lifting mechanism, resulting in an increase in equipment cost. In addition, although sandblasting passivation can improve the cutting edge morphology, it has defects such as abrasive splash polluting the environment and poor passivation uniformity (especially for tools with complex cutting edge shapes); Although the electro-chemical-rheological passivation process proposed in CN202310561688 improves the efficiency through electro-chemical oxidation, the cobalt binder phase in cemented carbide is prone to preferential loss due to its high electro-chemical activity, resulting in a decrease in the mechanical properties of the tool. Summary of the Invention

[0003] The present invention provides a passivation process for the cutting edge of a cemented carbide milling cutter, aiming to solve the above problems.

[0004] The present invention is implemented as follows. A passivation process for the cutting edge of a cemented carbide milling cutter includes the following steps: Prepare a passivation solution containing Fe 3+ and Zn 2+ The passivation solution contains abrasive particles and a nano-reinforcing phase; Immerse the tool in the passivation solution for chemical-mechanical composite treatment; Perform plasma shock treatment on the cutting edge; Reconstruct the grain boundaries of the cutting edge by laser irradiation.

[0005] Preferably, the Fe 3+ in the passivation solution is derived from ferric nitrate; Zn 2+ is derived from zinc sulfate; the abrasive particles include 0.5 - 1.5 μm diamond micropowder, and the nano-reinforcing phase includes nano h-BN (20 - 80 nm, specific surface area > 40 m 2 / g), Fe 3+ preferably reacts with the WC phase to form a dense FeWO4 passivation film, and Zn 2+The Co bonding phase is infiltrated to form a Zn-Co alloy layer, and nano-h-BN fills the microscopic pores to achieve chemical-mechanical synergistic passivation.

[0006] Preferably, the passivation solution comprises the following raw materials: Ferric nitrate 10-15g / L Zinc sulfate 8-12g / L Chelating agent 5-8g / L Diamond powder 20-30g / L Nano h-BN 3-5g / L Cerium nitrate 0.5-1.5g / L Hydrofluoric acid 0.5-1mL / L Modified chitosan 0.5-1g / L The pH value of the passivation solution is 3.5-4.0.

[0007] Fe 3+ It undergoes redox reaction with the WC phase (tungsten carbide) in cemented carbide, and the generated FeWO4 film (iron tungstate) covers the cutting edge in the form of nanocrystals, fills microcracks, reduces surface activity, and Zn 2+ Penetrate into the Co bonding phase, form a Zn-Co alloy layer through substitution reaction, improve the toughness of the cutting edge, inhibit crack propagation, and control the release rate of metal ions through chelating agents (at least one of EDTA, citric acid or tartaric acid) to avoid excessive reaction leading to loose film layer, while preventing Fe 3+ / Zn 2+ Precipitation failure, diamond powder is assisted by ultrasound to perform nano-scale cutting on the edge surface, remove burrs and homogenize the edge morphology, nano h-BN acts as a "soft abrasive" to fill the microscopic pores after diamond cutting, and at the same time plays a solid lubricating role, Ce 3+ It preferentially adsorbs on the WC grain boundary and generates CeO2 nanoparticles (size 5-10nm) through hydrolysis to fill the lattice gap of FeWO4 film; the redox properties of CeO2 (Ce 3+ / Ce 4+ Conversion) can dynamically repair the defects of the passivation film and improve the corrosion resistance. The WC surface is slightly corroded by hydrofluoric acid to remove the oxide layer and increase the reactive sites. The modified chitosan prevents the agglomeration of diamond / h-BN particles through the steric hindrance effect, ensuring the uniformity of abrasive distribution.

[0008] Preferably, the preparation method of the passivation solution is as follows: add the chelating agent, ferric nitrate and zinc sulfate to 60°C deionized water in sequence, and stir magnetically for 30 minutes; add diamond powder, nano h-BN and cerium nitrate successively, and disperse ultrasonically (40kHz, 30 minutes); add hydrofluoric acid and modified chitosan, and adjust the pH to 3.5-4.0 (which can be adjusted with dilute ammonia water); and let it stand for 12 hours for use.

[0009] Preferably, the preparation method of the modified chitosan is as follows: by weight, dissolve 10-15 parts of chitosan in 80-100 parts of 1% acetic acid solution, stir magnetically (500 rpm, 50 °C) until completely dissolved, take 2-4 parts of epoxy-capped PEG (PEG-DE, molecular weight 4000) and dissolve it in 50 mL of deionized water, and gradually add it dropwise to the chitosan solution; adjust the pH to 9.0-10.0 (slowly add 0.1 M NaOH dropwise), raise the temperature to 60 °C, and react for 24 h; add 5 mL of ethylene glycol to terminate the reaction (consume unreacted epoxy groups), pour the reaction solution into an excessive amount of absolute ethanol (volume ratio 1:3) for precipitation, centrifuge (8000 rpm, 10 min) to collect the precipitate, wash it 3 times with ethanol-water (70:30), and freeze-dry to obtain the modified chitosan. The steric hindrance effect of the PEG segment inhibits the aggregation of nanoparticles (h-BN, diamond), and the protonation of the amino group of chitosan (pH < 6.5) and the hydrophilicity of PEG act synergistically to form a stable colloidal system.

[0010] Preferably, the chemical-mechanical composite treatment by immersing the tool in the passivation solution is specifically as follows: first, immerse the tool in an acetone-ethanol mixture (volume ratio 1:1) for ultrasonic cleaning for 10 min (40 kHz, 60 °C), and dry it with nitrogen; then vertically fix the tool on the fixture and immerse it in the passivation solution (the liquid level is 10 mm higher than the cutting edge); turn on the ultrasonic vibration (power 100 W, 28 kHz, pulse mode: work for 2 s / interval for 1 s); maintain the temperature of the passivation solution at 50 ± 2 °C, and the treatment time is 10-15 min (adjust according to the R angle of the cutting edge, the target value of the R angle is 0.01-0.03 mm); simultaneously turn on the solution circulation (flow rate 1.5 L / min) to avoid abrasive settlement.

[0011] Multi-scale coordination: Chemical passivation (nanoscale): The FeWO4 film (<100 nm) fills atomic-level defects; Mechanical grinding (micrometer scale): Diamond micropowder corrects the cutting edge profile; Nano-strengthening (sub-micrometer scale): h-BN improves surface integrity.

[0012] Phase reaction control: Fe 3+ Selective reaction: Only reacts with the WC phase to avoid damaging the Co binder phase; Zn 2+ Gradient penetration: Forms a concentration gradient in the Co phase to optimize the stress distribution.

[0013] Preferably, the plasma shock treatment of the cutting edge is specifically as follows: Load the passivated tool into the vacuum chamber and evacuate to 5×10 -3Pa; Introduce argon gas until dynamic equilibrium (pressure fluctuation < ±1%); Turn on the plasma source (frequency 100 - 200 kHz, power density 3 - 6 kW / cm 2 , impact time 60 - 120 s), adjust the beam focusing to the edge area (spot diameter 2 mm); Start the pulsed impact (30 s each time, rotate the tool 60° during the interval to ensure uniform treatment), bombard the edge surface with high-frequency pulsed plasma to eliminate sub-micron defects on the edge, and the chemical film formation of the passivation liquid and the plasma impact form a "nano-sealing - micro-region strengthening" double composite layer.

[0014] Preferably, the reconstruction of the edge grain boundary by laser irradiation is specifically as follows: Fix the tool on a five-axis precision displacement platform, align the laser focus with the edge peak; Set the scanning path to ensure that the laser beam covers the entire edge area (width 0.1 - 0.3 mm); Start the laser irradiation, and simultaneously introduce argon gas for protection (flow rate 10 L / min) to prevent oxidation; Monitor the surface temperature in real time (infrared thermal imager, control the peak temperature < 800 °C), and through the local remelting of the Co phase at the grain boundary, promote the formation of preferred orientation of WC grains, improve the edge chipping resistance, and the laser reconstruction precisely regulates the grain boundary structure, breaking through the material removal limitation of traditional passivation.

[0015] Preferably, the laser irradiation uses a pulsed laser with a wavelength of 500 - 600 nm, an energy density of 3 - 6 J / cm 2 , scanning speed 150 - 250 mm / s, and spot overlap rate 20 - 40%.

[0016] Compared with the prior art, the embodiments of the present application mainly have the following beneficial effects: The cemented carbide milling cutter edge passivation process provided by the present invention combines chemical - mechanical - energy field composite action, metal ion passivation reaction and plasma / laser modification, and through the synergistic effect of metal ion selective passivation, grain boundary engineering regulation and nano-reinforcement, realizes the atomic-level reconstruction of the cemented carbide edge and the multi-scale optimization of structure strengthening; Specifically: Fe 3+ reacts with the WC phase (tungsten carbide) in the cemented carbide through an oxidation-reduction reaction, and the formed FeWO4 film (ferric tungstate) covers the edge in the form of nanocrystals, fills the microcracks, reduces the surface activity, Zn 2+Penetrate into the Co binder phase, form a Zn-Co alloy layer through a displacement reaction, improve the toughness of the cutting edge, inhibit crack propagation. Nano h-BN, as a "soft abrasive", fills the microscopic pores after diamond cutting. Then, by using high-frequency pulsed plasma to bombard the surface of the cutting edge, sub-micron defects at the cutting edge are eliminated. The chemical film formation of the passivation liquid and the plasma impact form a "nano-sealing and micro-region strengthening" double composite layer. Finally, through laser reconstruction, the grain boundary structure is precisely regulated, causing local remelting of the Co phase at the grain boundary, promoting the preferred orientation of WC grains, and improving the anti-chipping ability of the cutting edge. Description of the Drawings

[0017] Figure 1 It is a flowchart of a passivation process for the cutting edge of a cemented carbide milling cutter provided by the present invention. Detailed Embodiments

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above description of the drawings are intended to cover non-exclusive inclusion. The terms "first", "second", etc. in the specification and claims of this application or the above drawings are used to distinguish different objects and not to describe a specific order.

[0019] Reference to "embodiment" herein means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of this application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0020] Embodiment 1 The embodiment of the present invention provides a passivation process for the cutting edge of a cemented carbide milling cutter, as Figure 1 shown, including the following steps: 1) Prepare a passivation liquid containing Fe 3+ and Zn 2+ The passivation liquid contains abrasive particles and nano-enhanced phases; 2) Immerse the cutting tool in a passivation solution for chemo-mechanical compound treatment: First, immerse the cutting tool in a mixed solution of acetone and ethanol (1:1 volume ratio) and ultrasonically clean it for 10 min (40 kHz, 60 °C), then dry it with nitrogen; then vertically fix the cutting tool to a fixture and immerse it in the passivation solution (the liquid level is 10 mm higher than the cutting edge); turn on the ultrasonic vibration (power 100 W, 28 kHz, pulse mode: work for 2 s / interval for 1 s); maintain the temperature of the passivation solution at 48 °C, and the treatment time is 10 min (adjusted according to the R angle of the cutting edge, the target value of the R angle is 0.02 mm); synchronously turn on the solution circulation (flow rate 1.5 L / min) to avoid abrasive sedimentation; 3) Perform plasma shock treatment on the cutting edge: Load the passivated cutting tool into a vacuum chamber and evacuate it to 5×10 -3 Pa; introduce argon gas to dynamic equilibrium (pressure fluctuation < ±1%); turn on the plasma source (frequency 100 kHz, power density 3 kW / cm 2 , shock time 60 s), adjust the beam focusing to the cutting edge area (spot diameter 2 mm); start the pulse shock (30 s each time, rotate the cutting tool 60° during the interval to ensure uniform treatment); 4) Reconstruct the grain boundary of the cutting edge by laser irradiation: Fix the cutting tool on a five-axis precision displacement platform, align the laser focus with the cutting edge peak; set the scanning path to ensure that the laser beam covers the entire cutting edge area (width 0.1 mm); start the laser irradiation, and synchronously introduce argon gas for protection (flow rate 10 L / min) to prevent oxidation; monitor the surface temperature in real time (infrared thermal imager, control the peak temperature < 800 °C), the laser irradiation uses pulsed laser with a wavelength of 500 nm, energy density 3 J / cm 2 , scanning speed 150 mm / s, spot overlap rate 20%.

[0021] Among them, the passivation solution includes the following raw materials: Iron nitrate 10 g / L Zinc sulfate 8 g / L Chelating agent 5 g / L Diamond micropowder 20 g / L Nano h-BN 3 g / L Cerium nitrate 0.5 g / L Hydrofluoric acid 0.5 mL / L Modified chitosan 0.5 g / L pH value of the passivation solution 3.5.

[0022] Further, the preparation method of the passivation solution is as follows: Add a chelating agent, ferric nitrate, and zinc sulfate to deionized water at 60°C in sequence, and stir magnetically for 30 min; successively add diamond micropowder, nano h-BN, and cerium nitrate, and disperse ultrasonically (40 kHz, 30 min); add hydrofluoric acid and modified chitosan, and adjust the pH to 3.5 (which can be adjusted with dilute ammonia water); let it stand and age for 12 hours for standby.

[0023] In this embodiment, the preparation method of the modified chitosan is as follows: By weight, dissolve 10 parts of chitosan in 80 parts of 1% acetic acid solution, and stir magnetically (500 rpm, 50°C) until completely dissolved. Take 2 parts of epoxy-capped PEG (PEG-DE, molecular weight 4000) and dissolve it in 50 mL of deionized water, and add it dropwise to the chitosan solution; adjust the pH to 9.0 (slowly add 0.1 M NaOH dropwise), raise the temperature to 60°C, and react for 24 h; add 5 mL of ethylene glycol to terminate the reaction (consume unreacted epoxy groups), pour the reaction solution into excessive absolute ethanol (volume ratio 1:3) for precipitation, centrifuge (8000 rpm, 10 min) to collect the precipitate, wash it 3 times with ethanol-water (70:30), and freeze-dry to obtain modified chitosan.

[0024] Example 2 The embodiment of the present invention provides a hard alloy milling cutter edge passivation process, as Figure 1 shown, including the following steps: 1) Prepare a passivation solution containing Fe 3+ and Zn 2+ , and the passivation solution contains abrasive particles and nano-reinforcing phases; 2) Immerse the cutter in the passivation solution for chemo-mechanical composite treatment: First, immerse the cutter in an acetone-ethanol mixed solution (volume ratio 1:1) and ultrasonically clean it for 10 min (40 kHz, 60°C), and dry it with nitrogen; then vertically fix the cutter on the fixture and immerse it in the passivation solution (the liquid level is 10 mm higher than the edge); turn on the ultrasonic vibration (power 100 W, 28 kHz, pulse mode: work for 2 s / interval for 1 s); maintain the temperature of the passivation solution at 48°C, and the treatment time is 10 min (adjust according to the edge R angle, the target value of the R angle is 0.02 mm); synchronously turn on the solution circulation (flow rate 1.5 L / min) to avoid abrasive settlement; 3) Perform plasma impact treatment on the edge: Load the passivated cutter into the vacuum chamber, evacuate to 5×10 -3 Pa; introduce argon to dynamic equilibrium (pressure fluctuation < ±1%); turn on the plasma source (frequency 100 kHz, power density 3 kW / cm 2 , impact time 60 s), adjust the beam focusing to the edge area (spot diameter 2 mm); start pulse impact (each time 30 s, rotate the cutter 60° during the interval to ensure uniform treatment); 4) Reconstruct the grain boundary of the cutting edge by laser irradiation: Fix the tool on a five-axis precision displacement platform, and align the laser focus with the tip of the cutting edge; Set the scanning path to ensure that the laser beam covers the entire cutting edge area (width 0.1 mm); Start laser irradiation, and simultaneously introduce argon gas for protection (flow rate 10 L / min) to prevent oxidation; Monitor the surface temperature in real time (using an infrared thermal imager, controlling the peak temperature < 800 °C). The laser irradiation uses pulsed laser with a wavelength of 500 nm, and the energy density is 3 J / cm 2 , the scanning speed is 150 mm / s, and the spot overlap rate is 20%.

[0025] Among them, the passivation solution includes the following raw materials: Iron nitrate 11 g / L Zinc sulfate 9 g / L Chelating agent 6 g / L Diamond micropowder 22 g / L Nano h-BN 3.5 g / L Cerium nitrate 0.8 g / L Hydrofluoric acid 0.6 mL / L Modified chitosan 0.6 g / L The pH value of the passivation solution is 3.5.

[0026] Furthermore, the preparation method of the passivation solution is as follows: Add the chelating agent, iron nitrate, and zinc sulfate to deionized water at 60 °C in sequence, and stir magnetically for 30 min; Add diamond micropowder, nano h-BN, and cerium nitrate successively, and disperse ultrasonically (40 kHz, 30 min); Add hydrofluoric acid and modified chitosan, and adjust the pH to 3.5 - 4.0 (can be adjusted with dilute ammonia water); Let it stand and age for 12 hours for standby.

[0027] In this embodiment, the preparation method of the modified chitosan is as follows: By weight, dissolve 10 parts of chitosan in 80 parts of 1% acetic acid solution, and stir magnetically (500 rpm, 50 °C) until completely dissolved. Take 2 parts of epoxy-terminated PEG (PEG-DE, molecular weight 4000) and dissolve it in 50 mL of deionized water, and add it dropwise to the chitosan solution; Adjust the pH to 9.0 (slowly add 0.1 M NaOH dropwise), raise the temperature to 60 °C, and react for 24 h; Add 5 mL of ethylene glycol to terminate the reaction (consume the unreacted epoxy groups), pour the reaction solution into excessive absolute ethanol (volume ratio 1:3) for precipitation, centrifuge (8000 rpm, 10 min) to collect the precipitate, wash it 3 times with ethanol-water (70:30), and freeze-dry to obtain modified chitosan.

[0028] Example 3 The embodiment of the present invention provides a passivation process for the cutting edge of a cemented carbide milling cutter, as Figure 1 shown, including the following steps: 1) Prepare a solution containing Fe3+ and Zn 2+ A passivation solution, the passivation solution containing abrasive particles and a nano-reinforcing phase; 2) Immerse the cutting tool in the passivation solution for chemo-mechanical composite treatment: First, immerse the cutting tool in an acetone-ethanol mixture (1:1 volume ratio) and ultrasonically clean it for 10 min (40 kHz, 60 °C), and dry it with nitrogen; then vertically fix the cutting tool to a fixture and immerse it in the passivation solution (the liquid level is 10 mm higher than the edge); turn on the ultrasonic vibration (power 100 W, 28 kHz, pulse mode: work for 2 s / interval for 1 s); maintain the temperature of the passivation solution at 50 °C, and the treatment time is 12.5 min (adjusted according to the R angle of the edge, the target value of the R angle is 0.02 mm); simultaneously turn on the solution circulation (flow rate 1.5 L / min) to avoid abrasive settlement; 3) Perform plasma shock treatment on the edge: Load the passivated cutting tool into a vacuum chamber and evacuate it to 5×10 -3 Pa; introduce argon gas to dynamic equilibrium (pressure fluctuation < ±1%); turn on the plasma source (frequency 150 kHz, power density 3 - 6 kW / cm 2 , shock time 60 - 120 s), adjust the beam focusing to the edge area (spot diameter 2 mm); start the pulsed shock (30 s each time, rotate the cutting tool 60° during the interval to ensure uniform treatment); 4) Reconstruct the grain boundary of the edge by laser irradiation: Fix the cutting tool on a five-axis precision displacement platform, align the laser focus with the edge peak; set the scanning path to ensure that the laser beam covers the entire edge area (width 0.2 mm); start the laser irradiation, and simultaneously introduce argon gas for protection (flow rate 10 L / min) to prevent oxidation; monitor the surface temperature in real time (infrared thermal imager, control the peak temperature < 800 °C), the laser irradiation uses a pulsed laser with a wavelength of 550 nm, an energy density of 4.5 J / cm 2 , scanning speed 200 mm / s, spot overlap rate 30%.

[0029] Among them, the passivation solution includes the following raw materials: Ferric nitrate 12.5 g / L Zinc sulfate 10 g / L Chelating agent 6.5 g / L Diamond micropowder 25 g / L Nano h-BN 4 g / L Cerium nitrate 1 g / L Hydrofluoric acid 0.75 mL / L Modified chitosan 0.75 g / L The pH value of the passivation solution is 3.8.

[0030] Further, the preparation method of the passivation solution is as follows: Add a chelating agent, iron nitrate, and zinc sulfate to deionized water at 60°C in sequence, and magnetically stir for 30 min; successively add diamond micropowder, nano h-BN, and cerium nitrate, and ultrasonically disperse (40 kHz, 30 min); add hydrofluoric acid and modified chitosan, and adjust the pH to 3.8 (which can be adjusted with dilute ammonia water); let it stand and age for 12 hours for standby.

[0031] In this example, the preparation method of the modified chitosan is as follows: By weight, dissolve 12.5 parts of chitosan in 90 parts of 1% acetic acid solution, and magnetically stir (500 rpm, 50°C) until completely dissolved. Take 3 parts of epoxy-terminated PEG (PEG-DE, molecular weight 4000) and dissolve it in 50 mL of deionized water, and gradually add it dropwise to the chitosan solution; adjust the pH to 9.5 (slowly add 0.1 M NaOH dropwise), raise the temperature to 60°C, and react for 24 h; add 5 mL of ethylene glycol to terminate the reaction (consume unreacted epoxy groups), pour the reaction solution into an excess of absolute ethanol (volume ratio 1:3) for precipitation, centrifuge (8000 rpm, 10 min) to collect the precipitate, wash it 3 times with ethanol-water (70:30), and freeze-dry to obtain modified chitosan.

[0032] Example 4 The embodiment of the present invention provides a hard alloy milling cutter edge passivation process, as Figure 1 shown, including the following steps: 1) Prepare a passivation solution containing Fe 3+ and Zn 2+ , and the passivation solution contains abrasive particles and nano-enhanced phases; 2) Immerse the cutter in the passivation solution for chemical-mechanical composite treatment: First, immerse the cutter in an acetone-ethanol mixed solution (volume ratio 1:1) and ultrasonically clean for 10 min (40 kHz, 60°C), and blow dry with nitrogen; then vertically fix the cutter on the fixture and immerse it in the passivation solution (the liquid level is 10 mm higher than the edge); turn on the ultrasonic vibration (power 100 W, 28 kHz, pulse mode: work for 2 s / intermittent for 1 s); maintain the temperature of the passivation solution at 52°C, and the treatment time is 15 min (adjust according to the R angle of the edge, the target value of the R angle is 0.02 mm); synchronously turn on the solution circulation (flow rate 1.5 L / min) to avoid abrasive settlement; 3) Perform plasma impact treatment on the edge: Load the passivated cutter into the vacuum chamber, evacuate to 5×10 -3 Pa; introduce argon to dynamic equilibrium (pressure fluctuation < ±1%); turn on the plasma source (frequency 200 kHz, power density 6 kW / cm 2 , impact time 120 s), adjust the beam focusing to the edge area (spot diameter 2 mm); start pulse impact (each time for 30 s, rotate the cutter 60° during the interval to ensure uniform treatment); 4) Reconstruct the grain boundary of the cutting edge by laser irradiation: Fix the cutting tool on a five-axis precision displacement platform, and align the laser focus with the tip of the cutting edge; Set the scanning path to ensure that the laser beam covers the entire cutting edge area (width 0.3 mm); Start laser irradiation, and simultaneously introduce argon gas for protection (flow rate 10 L / min) to prevent oxidation; Monitor the surface temperature in real time (using an infrared thermal imager, controlling the peak temperature <800 °C). The laser irradiation uses pulsed laser with a wavelength of 600 nm, and the energy density is 6 J / cm 2 , the scanning speed is 250 mm / s, and the spot overlap rate is 40%.

[0033] Among them, the passivation solution includes the following raw materials: Iron nitrate 14 g / L Zinc sulfate 11 g / L Chelating agent 7 g / L Diamond micropowder 27 g / L Nano h-BN 4.5 g / L Cerium nitrate 1.2 g / L Hydrofluoric acid 0.9 mL / L Modified chitosan 0.9 g / L The pH value of the passivation solution is 4.0.

[0034] Furthermore, the preparation method of the passivation solution is as follows: Add the chelating agent, iron nitrate, and zinc sulfate to deionized water at 60 °C in sequence, and stir magnetically for 30 min; Add diamond micropowder, nano h-BN, and cerium nitrate successively, and disperse ultrasonically (40 kHz, 30 min); Add hydrofluoric acid and modified chitosan, and adjust the pH to 4.0 (it can be adjusted with dilute ammonia water); Let it stand and age for 12 hours for standby.

[0035] In this embodiment, the preparation method of the modified chitosan is as follows: By weight, dissolve 15 parts of chitosan in 100 parts of 1% acetic acid solution, stir magnetically (500 rpm, 50 °C) until completely dissolved, take 4 parts of epoxy-terminated PEG (PEG-DE, molecular weight 4000) and dissolve it in 50 mL of deionized water, and add it dropwise to the chitosan solution; Adjust the pH to 10.0 (slowly add 0.1 M NaOH dropwise), raise the temperature to 60 °C, and react for 24 h; Add 5 mL of ethylene glycol to terminate the reaction (consume the unreacted epoxy groups), pour the reaction solution into excessive absolute ethanol (volume ratio 1:3) for precipitation, centrifuge (8000 rpm, 10 min) to collect the precipitate, wash it 3 times with ethanol-water (70:30), and freeze-dry to obtain modified chitosan.

[0036] Example 5 The embodiment of the present invention provides a hard alloy milling cutter cutting edge passivation process, as Figure 1 shown, including the following steps: 1) Prepare a passivation solution containing Fe 3+ and Zn 2+ The passivation solution contains abrasive particles and a nano-reinforcing phase; 2) Immerse the cutting tool in the passivation solution for chemo-mechanical composite treatment: First, immerse the cutting tool in an acetone-ethanol mixture (1:1 volume ratio) and ultrasonically clean it for 10 min (40 kHz, 60 °C), and then dry it with nitrogen; then vertically fix the cutting tool to a fixture and immerse it in the passivation solution (the liquid level is 10 mm higher than the edge); turn on the ultrasonic vibration (power 100 W, 28 kHz, pulse mode: work for 2 s / interval for 1 s); maintain the temperature of the passivation solution at 52 °C, and the treatment time is 15 min (adjusted according to the R angle of the edge, the target value of the R angle is 0.02 mm); simultaneously turn on the solution circulation (flow rate 1.5 L / min) to avoid abrasive sedimentation; 3) Perform plasma shock treatment on the edge: Load the passivated cutting tool into a vacuum chamber and evacuate it to 5×10 -3 Pa; introduce argon gas to dynamic equilibrium (pressure fluctuation < ±1%); turn on the plasma source (frequency 200 kHz, power density 6 kW / cm 2 , shock time 120 s), adjust the beam focusing to the edge area (spot diameter 2 mm); start the pulsed shock (30 s each time, rotate the cutting tool 60° during the interval to ensure uniform treatment); 4) Reconstruct the grain boundary of the edge by laser irradiation: Fix the cutting tool on a five-axis precision displacement platform, align the laser focus with the edge peak; set the scanning path to ensure that the laser beam covers the entire edge area (width 0.3 mm); start the laser irradiation, and simultaneously introduce argon gas for protection (flow rate 10 L / min) to prevent oxidation; monitor the surface temperature in real time (infrared thermal imager, control the peak temperature < 800 °C), the laser irradiation uses a pulsed laser with a wavelength of 600 nm, an energy density of 6 J / cm 2 , scanning speed 250 mm / s, spot overlap rate 40%.

[0037] Among them, the passivation solution includes the following raw materials: Ferric nitrate 15 g / L Zinc sulfate 12 g / L Chelating agent 8 g / L Diamond micropowder 30 g / L Nano h-BN 5 g / L Cerium nitrate 1.5 g / L Hydrofluoric acid 1 mL / L Modified chitosan 1 g / L pH value of the passivation solution 4.0.

[0038] Further, the preparation method of the passivation solution is as follows: sequentially add a chelating agent, iron nitrate, and zinc sulfate into deionized water at 60°C, and magnetically stir for 30 min; successively add diamond micropowder, nano h-BN, and cerium nitrate, and ultrasonically disperse (40 kHz, 30 min); add hydrofluoric acid and modified chitosan, and adjust the pH to 4.0 (which can be adjusted with dilute ammonia water); let it stand and age for 12 hours for standby.

[0039] In this embodiment, the preparation method of the modified chitosan is as follows: by weight, dissolve 15 parts of chitosan in 100 parts of 1% acetic acid solution, and magnetically stir (500 rpm, 50°C) until completely dissolved. Take 4 parts of epoxy-terminated PEG (PEG-DE, molecular weight 4000) and dissolve it in 50 mL of deionized water, and gradually drop it into the chitosan solution; adjust the pH to 10.0 (slowly drop 0.1 M NaOH), raise the temperature to 60°C, and react for 24 h; add 5 mL of ethylene glycol to terminate the reaction (consuming the unreacted epoxy groups), pour the reaction solution into an excessive amount of absolute ethanol (volume ratio 1:3) for precipitation, centrifuge (8000 rpm, 10 min) to collect the precipitate, wash it 3 times with ethanol-water (70:30), and freeze-dry to obtain the modified chitosan.

[0040] Comparative Example 1 Only use a ceramic grinding wheel (#2000 mesh) for mechanical grinding, with an R angle of 0.02 mm No chemical treatment and energy field process Comparative Example 2 The passivation solution removes Fe 3+ / Zn 2+ salt, only retain diamond micropowder (25 g / L), and the other steps are the same as in Example 3.

[0041] Comparative Example 3 Do not perform the plasma treatment step, and the other steps are the same as in Example 3.

[0042] Comparative Example 4 Do not perform the step of laser irradiation to reconstruct the grain boundaries of the cutting edge, and the other steps are the same as in Example 3.

[0043] Comparative Example 5 The passivation solution removes Fe 3+ / Zn 2+ salt, only retain diamond micropowder (25 g / L), and do not perform the plasma treatment step and the step of laser irradiation to reconstruct the grain boundaries of the cutting edge, and the other steps are the same as in Example 3.

[0044] Perform performance tests on the milling cutters of Example 3 and Comparative Examples 1 and 2, and the test results are shown in Table 1 below: Table 1 Milling cutter performance test result table Test item Example 3 Comparative example 1 Comparative example 2 Comparative example 3 Comparative example 4 Comparative example 5 Edge Ra (μm) 0.05 0.25 0.18 0.10 0.12 0.30 Number of cycles of edge chipping resistance 38000 10000 15000 22000 18000 8000 Cutting life (min) 42 14 23 28 25 10 Residual stress (Mpa) -160 +200 -30 +50 -80 +250 Among them, the number of anti-edge-breaking cycles is the number of times of milling TC4 titanium alloy with an axial cutting depth of 1.0 mm until an edge break of >0.1 mm occurs. The cutting life is the continuous cutting time when the flank wear VB = 0.2 mm. In the residual stress, "+" represents tensile stress and "-" represents compressive stress.

[0045] As can be seen from the above results, based on chemical passivation, the composite passivation film formed by the Fe 3+ / Zn 2+ reaction improves the mechanical properties of the milling cutter edge. Plasma impact and laser reconstruction solve the problems of micro-defects and grain boundary weakening through energy field coupling. The synergistic effect of the three further improves the edge strength.

[0046] It should be noted that for the foregoing embodiments, for the sake of simple description, they are all expressed as a series of action combinations. However, those skilled in the art should know that the present invention is not limited by the described action sequence, because according to the present invention, certain steps may be performed in other sequences or simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all preferred embodiments, and the actions and modules involved are not necessarily essential to the present invention.

[0047] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on these embodiments, all other embodiments obtained by those of ordinary skill in the art without creative work belong to the scope of protection of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art can still, without conflict, make combinations, additions, deletions or other adjustments to the features in the embodiments of the present invention according to the situation without creative work, so as to obtain different technical solutions that essentially do not deviate from the concept of the present invention, and these technical solutions also belong to the scope of protection of the present invention.

Claims

1. A carbide milling cutter edge passivation process, characterized in that, It includes the following steps: Prepare a passivation solution containing Fe 3+ and Zn 2+ The passivation solution contains abrasive particles and a nano-reinforcing phase; Immerse the cutting tool in a passivation solution for chemo-mechanical composite treatment; Perform plasma shock treatment on the cutting edge; Reconstruct the grain boundary of the cutting edge by laser irradiation.

2. The cemented carbide milling cutter edge passivation process according to claim 1, characterized in that, The Fe in the passivation solution 3+ is derived from ferric nitrate; the Zn 2+ is derived from zinc sulfate; the abrasive particles include diamond micropowder with a size of 0.5 - 1.5 μm, and the nano-enhanced phase includes nano h-BN.

3. The carbide milling cutter edge passivation process according to claim 2, characterized in that, The passivation solution includes the following raw materials: Ferric nitrate 10 - 15 g / L Zinc sulfate 8 - 12 g / L Chelating agent 5 - 8 g / L Diamond micropowder 20 - 30 g / L Nano h-BN 3 - 5 g / L Cerium nitrate 0.5 - 1.5 g / L Hydrofluoric acid 0.5 - 1 mL / L Modified chitosan 0.5 - 1 g / L The pH value of the passivation solution is 3.5 - 4.

0.

4. The cemented carbide milling cutter edge passivation process according to claim 3, characterized in that, The preparation method of the passivation solution is as follows: Add the chelating agent, ferric nitrate, and zinc sulfate to deionized water at 60°C in sequence, and stir magnetically for 30 min; add diamond micropowder, nano h-BN, and cerium nitrate successively, and disperse ultrasonically; add hydrofluoric acid and modified chitosan, and adjust the pH to 3.5 - 4.0; let it stand and age for 12 hours for standby.

5. The cemented carbide milling cutter edge passivation process according to claim 4, characterized in that, The preparation method of the modified chitosan is as follows: By weight, dissolve 10 - 15 parts of chitosan in 80 - 100 parts of 1% acetic acid solution, and stir magnetically until completely dissolved. Take 2 - 4 parts of epoxy-terminated PEG and dissolve it in 50 mL of deionized water, and add it dropwise to the chitosan solution; adjust the pH to 9.0 - 10.0, raise the temperature to 60°C, and react for 24 h; add 5 mL of ethylene glycol to terminate the reaction, pour the reaction solution into excessive absolute ethanol for precipitation, centrifuge to collect the precipitate, wash it 3 times with ethanol-water, and freeze-dry to obtain the modified chitosan.

6. The carbide milling cutter edge passivation process according to claim 1, wherein, The specific operation of immersing the cutting tool in the passivation solution for chemo-mechanical composite treatment is as follows: First, immerse the cutting tool in an acetone-ethanol mixed solution and ultrasonically clean it for 10 min, and then dry it with nitrogen; then vertically fix the cutting tool on the fixture and immerse it in the passivation solution; turn on the ultrasonic vibration; maintain the temperature of the passivation solution at 50 ± 2°C, and the treatment time is 10 - 15 min; synchronously turn on the solution circulation.

7. The carbide milling cutter edge passivation process according to claim 1, characterized in that, The plasma shock treatment of the cutting edge is specifically as follows: The passivated tool is loaded into a vacuum chamber, and the vacuum is pumped to 5×10 -3 Pa; argon is introduced until dynamic equilibrium is reached; the plasma source is turned on, and the beam current is adjusted to focus on the cutting edge area; the pulse shock is started.

8. The cemented carbide milling cutter edge passivation process according to claim 1, characterized in that, The specific operation of reconstructing the grain boundary of the cutting edge by laser irradiation is as follows: Fix the cutting tool on a five-axis precision displacement platform, align the laser focus with the tip of the cutting edge; set the scanning path to ensure that the laser beam covers the entire cutting edge area; start laser irradiation, and synchronously introduce argon gas for protection to prevent oxidation; monitor the surface temperature in real time.

9. The cemented carbide milling cutter edge passivation process according to claim 8, characterized in that, The laser irradiation uses pulsed laser with a wavelength of 500 - 600 nm, an energy density of 3 - 6 J / cm 2 , a scanning speed of 150 - 250 mm / s, and a spot overlap rate of 20 - 40%.

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