Anti-fatigue heat-resistant high-speed steel cutter and preparation method thereof

Abstract

The present application relates to the technical field of metal surface plating treatment, in particular to a kind of anti-fatigue heat-resistant high-speed steel cutter and its preparation method, comprising the following steps: pickling and cleaning;Multi-layer gradient deposition.Cr-FeSiB prepared by the primer layer realizes firm metallurgical bonding with the matrix through Cr, and absorbs stress and passivates crack by the unique structure of FeSiB amorphous alloy, providing an innovative solution to solve the bonding force and toughness bottleneck.TiAlCN-SiC transition layer inherits the high hardness and thermal stability of TiAlCN, and significantly improves the toughness and high-temperature stability of the layer body using SiC, achieving perfect gradient transition of performance.

Description

Technical Field

[0001] This invention relates to the field of metal surface coating technology, specifically to a fatigue-resistant and heat-resistant high-speed steel cutting tool and its preparation method. Background Technology

[0002] In high-speed cutting of difficult-to-machine materials such as high-speed steel, cutting tools often face a series of technical bottlenecks, including insufficient bonding strength, poor toughness, decreased wear resistance, and high-temperature adhesion. Traditional single or simple composite coatings, due to abrupt changes in interlayer properties, weak interfacial bonding, insufficient toughness, and poor high-temperature stability, are unable to meet the stringent requirements of modern high-efficiency machining for tool life and stability. Especially in the machining of high-speed steel, the workpiece material is prone to adhesion to the tool surface, leading to fluctuations in cutting force, work hardening, and premature tool failure, which severely restricts machining efficiency and surface quality.

[0003] While existing coating technologies have made some progress in terms of hardness and wear resistance, they still fall short in achieving a synergistic improvement in high bonding strength, high toughness, and excellent thermal fatigue resistance between the coating and the substrate. For example, conventional undercoating methods often fail to balance metallurgical bonding and stress buffering, transition layers frequently lack effective toughening and thermal stability design, and functional layers still have limitations in high-temperature lubrication and oxidation resistance. Furthermore, the surface condition of the high-speed steel substrate before magnetron sputtering has a decisive influence on the coating bonding strength and defect rate. Traditional pickling and activation processes suffer from incomplete cleaning, uneven activation, and susceptibility to over-corrosion, making it difficult to provide an ideal highly active and clean coating surface.

[0004] Therefore, there is an urgent need to develop a new type of high-speed steel cutting tool and its supporting manufacturing process. Through innovative design of coating structure and optimization of substrate pretreatment process, the above-mentioned technical problems can be systematically solved, and the overall service performance of the cutting tool can be comprehensively improved. Summary of the Invention

[0005] To address the shortcomings of existing technologies, the present invention aims to provide a fatigue-resistant and heat-resistant high-speed steel cutting tool and its preparation method.

[0006] A fatigue-resistant and heat-resistant high-speed steel cutting tool includes a high-speed steel cutting tool substrate and a Cr-FeSiB base layer, a TiAlCN-SiC transition layer, and a Y2O3-TiAlCN main layer that are magnetron sputtered and deposited on the surface of the high-speed steel cutting tool substrate from the inside to the outside. In the Cr-FeSiB base layer, the atomic ratios of Cr, Fe, Si, and B, expressed as percentages, are 60-70%, 20-25%, 5-10%, and 1-5%, respectively. In the TiAlCN-SiC transition layer, the atomic ratios of Ti, Al, C, N, and Si, expressed as percentages, are 15-20%, 50-60%, 10-15%, 10-15%, and 1-5%, respectively. In the Y2O3-TiAlCN host layer, the atomic percentages of Y, O, Ti, Al, C and N are 0.5-2%, 1-3%, 30-40%, 30-40%, 15-20%, and 10-15%, respectively.

[0007] Furthermore, the high-speed steel tool base is one of M2, M35 or M42.

[0008] A method for preparing a fatigue-resistant and heat-resistant high-speed steel cutting tool includes the following steps: S1: Pickling and Cleaning The high-speed steel tool substrate is subjected to pickling, pulse current connection and cleaning to obtain the treated high-speed steel tool substrate; S2: Multi-layer gradient deposition Cr and FeSiB targets are turned on, and Cr-FeSiB is deposited in a pure Ar atmosphere to magnetron sputter Cr-FeSiB as a base layer on a high-speed steel tool substrate to obtain a tool with a base layer. Keep the FeSiB target at low power, turn on the TiAl and SiC targets, and introduce a mixture of N2 and CH4 gas, while turning off the FeSiB target. This forms a TiAlCN-SiC transition layer on the bottom layer tool, resulting in a transition layer tool. With the SiC target turned off, the graphene composite target embedded with Y2O3 was turned on and co-sputtered with the TiAl target to deposit the final Y2O3-TiAlCN host layer in an Ar / N2 atmosphere, thus obtaining a fatigue-resistant and heat-resistant high-speed steel cutting tool.

[0009] Furthermore, the thickness of the Cr-FeSiB underlayer is 0.1-1 μm, the thickness of the TiAlCN-SiC transition layer is 1-5 μm, and the thickness of the Y2O3-TiAlCN main layer is 2-10 μm.

[0010] Furthermore, step S1 specifically includes: Place the high-speed steel substrate in a vacuum chamber and preheat it to 60-70℃ for 30-40 minutes. Then immerse it in a water-based pickling solution to completely submerge the high-speed steel substrate. Finally, treat it with ultrasonic waves at 40-60kHz for 5-10 minutes. In the last 2 minutes of pickling, the high-speed steel workpiece is connected to a pulsed current, set as the cathode of the pulsed current, and a pulsed current with a density of 10-20 mA / cm² and a pulse frequency of 100 Hz is applied. Finally, it is taken out of the water-based pickling solution, rinsed 2-3 times with ultrapure water mixed with oxygen, and air-dried to obtain the treated high-speed steel tool substrate.

[0011] Furthermore, the preparation process of the water-based pickling solution is as follows: Measure 800-850 parts by weight of deionized water and pour it into the reactor. Place the reactor on a magnetic stirrer and start stirring at a speed of 300-400 r / min. Weigh 10-20 parts by weight of aminosulfonic acid and slowly add it to the deionized water while stirring continuously. After it is completely dissolved, weigh 4-6 parts by weight of citric acid and add it to the reactor while stirring. Stir until it is completely dissolved and the solution is clear. Adjust the magnetic stirrer speed to 500-600 r / min, weigh 0.2-0.4 parts by mass of cerium sulfate, add the cerium sulfate powder to the reactor, weigh 0.75-1.5 parts by mass of hydroxyurea, add the hydroxyurea to the reactor, and stir until completely dissolved; Add 0.03-0.05 parts by weight of fluorocarbon surfactant and 0.06-1 parts by weight of alkynol corrosion inhibitor, stir at 500-600 r / min for 15-30 minutes to obtain water-based pickling solution.

[0012] Furthermore, in the N2 and CH4 mixture, the volume ratio of N2 to CH4 is (4-5):1.

[0013] Furthermore, the volume ratio of Ar to N2 in the Ar / N2 atmosphere is (3-4):1.

[0014] The present invention has the following advantages: 1. The Cr-FeSiB underlayer prepared in this invention achieves a strong metallurgical bond with the substrate through Cr, and utilizes the unique structure of the FeSiB amorphous alloy to absorb stress and passivate cracks, providing an innovative solution to the bottleneck of bonding strength and toughness. The core advantage of the TiAlCN-SiC transition layer lies in the formation of a composite structure of "nanocrystalline TiAlCN embedded in an amorphous SiC matrix". While inheriting the high hardness and thermal stability of TiAlCN, it utilizes SiC to significantly improve the toughness and high-temperature stability of the layer, achieving a perfect gradient transition of performance. The outermost Y2O3-TiAlCN functional layer toughens and provides lubrication through the pull-out and bridging effect of graphene, while the presence of Y2O3 also significantly improves the coating's resistance to high-temperature oxidation and thermal stability. The three work synergistically to endow the tool with exceptional bonding strength, fatigue resistance, wear resistance, and thermal shock resistance, providing a systematic solution specifically for the problems of tool sticking, hardening, and high temperature in high-speed steel machining.

[0015] 2. The water-based pickling solution prepared in this invention provides an efficient cleaning and activation solution for the pretreatment of high-speed steel before magnetron sputtering through the synergistic effect of multiple components. Its core advantages lie in the fact that sulfamic acid, as the main acid, can effectively and uniformly dissolve the oxide scale and passivation film on the surface of high-speed steel, while avoiding excessive corrosion of the substrate; citric acid, by complexing the dissolved metal ions, prevents their redeposition and surface contamination. The innovative redox cycle system composed of cerium sulfate and hydroxyurea can continuously disrupt the most stable passivation layer, achieving deep chemical activation of the surface. The addition of fluorocarbon surfactants significantly improves the solution's penetration ability, ensuring that impurities in micro-crevices are effectively removed, while alkynyl alcohol corrosion inhibitors, through selective adsorption, suppress the risk of over-corrosion of the substrate material and maintain the uniformity of the surface morphology. This series of synergistic effects ultimately provides the magnetron sputtering process with a clean, highly active substrate surface with an ideal microstructure. This is a key prerequisite for achieving high bonding strength, excellent uniformity, and low defect rate in the coating, directly determining the comprehensive performance and service reliability of the subsequent coating. Attached Figure Description

[0016] Figure 1 This is a flowchart illustrating the preparation method of the fatigue-resistant and heat-resistant high-speed steel cutting tool of the present invention. Detailed Implementation

[0017] Example 1: A fatigue-resistant and heat-resistant high-speed steel cutting tool includes a high-speed steel cutting tool substrate and a Cr-FeSiB base layer, a TiAlCN-SiC transition layer and a Y2O3-TiAlCN main layer sequentially magnetron sputtered on the surface of the high-speed steel cutting tool substrate from the inside to the outside. The high-speed steel cutting tool substrate is M2. In the Cr-FeSiB base layer, the atomic ratios of Cr, Fe, Si, and B, expressed as percentages, are 60%, 25%, 10%, and 5%, respectively. In the TiAlCN-SiC transition layer, the atomic ratios of Ti, Al, C, N, and Si, expressed as percentages, are 15%, 50%, 15%, 15%, and 5%, respectively. In the Y2O3-TiAlCN host layer, the atomic percentages of Y, O, Ti, Al, C and N are 0.5%, 1%, 30%, 40%, 18.5% and 10%, respectively.

[0018] A method for preparing fatigue-resistant and heat-resistant high-speed steel cutting tools, such as... Figure 1 As shown, it includes the following steps: S1: Pickling and Cleaning The high-speed steel substrate was placed in a vacuum chamber and preheated at 60°C for 30 minutes. Then it was immersed in a water-based pickling solution, ensuring that the water-based pickling solution completely submerged the high-speed steel substrate. Finally, it was treated with 40kHz ultrasound for 5 minutes. In the last 2 minutes of pickling, the high-speed steel workpiece is connected to a pulsed current, set as the cathode of the pulsed current, and a pulsed current with a density of 10 mA / cm² and a pulse frequency of 100 Hz is applied. Finally, it is taken out of the water-based pickling solution, rinsed twice with ultrapure water mixed with oxygen, and air-dried to obtain the treated high-speed steel tool substrate.

[0019] The preparation process of water-based pickling solution is as follows: Measure 800 parts by mass of deionized water and pour it into the reactor. Place the reactor on a magnetic stirrer and start stirring at 300 r / min. Weigh 10 parts by mass of aminosulfonic acid and slowly add it to the deionized water while stirring continuously. After it is completely dissolved, weigh 4 parts by mass of citric acid and add it to the reactor while stirring. Stir until it is completely dissolved and the solution is clear. Adjust the magnetic stirrer speed to 500 r / min, weigh 0.2 parts by mass of cerium sulfate, add the cerium sulfate powder to the reactor, weigh 0.75 parts by mass of hydroxyurea, add the hydroxyurea to the reactor, and stir until completely dissolved; Add 0.03 parts by weight of fluorocarbon surfactant and 0.06 parts by weight of alkynol corrosion inhibitor, stir at 500 r / min for 15-30 minutes to obtain water-based pickling solution.

[0020] S2: Multi-layer gradient deposition Cr and FeSiB targets are turned on, and Cr-FeSiB is deposited in a pure Ar atmosphere to magnetron sputter Cr-FeSiB as a base layer on a high-speed steel tool substrate to obtain a tool with a base layer. Keep the FeSiB target at low power, turn on the TiAl and SiC targets, and introduce a mixed gas of N2 and CH4 with a volume ratio of 4:1. At the same time, turn off the FeSiB target to form a TiAlCN-SiC transition layer on the bottom layer tool to obtain the transition layer tool. With the SiC target turned off, the graphene composite target embedded with Y2O3 was turned on and co-sputtered with the TiAl target to deposit the final Y2O3-TiAlCN host layer in an Ar / N2 atmosphere. The volume ratio of Ar to N2 in the Ar / N2 atmosphere was 3:1, resulting in a fatigue-resistant and heat-resistant high-speed steel cutting tool.

[0021] The thickness of the Cr-FeSiB underlayer is 0.1 μm, the thickness of the TiAlCN-SiC transition layer is 1 μm, and the thickness of the Y2O3-TiAlCN main layer is 2 μm.

[0022] Example 2: A fatigue-resistant and heat-resistant high-speed steel cutting tool includes a high-speed steel cutting tool substrate and a Cr-FeSiB base layer, a TiAlCN-SiC transition layer and a Y2O3-TiAlCN main layer sequentially magnetron sputtered on the surface of the high-speed steel cutting tool substrate from the inside to the outside. The high-speed steel cutting tool substrate is M2. In the Cr-FeSiB base layer, the atomic ratios of Cr, Fe, Si, and B, expressed as percentages, are 70%, 20%, 5%, and 5%, respectively. In the TiAlCN-SiC transition layer, the atomic ratios of Ti, Al, C, N, and Si, expressed as percentages, are 20%, 50%, 14%, 15%, and 1%, respectively. In the Y2O3-TiAlCN host layer, the atomic percentages of Y, O, Ti, Al, C, and N are 2%, 3%, 30%, 30%, 20%, and 15%, respectively.

[0023] A method for preparing fatigue-resistant and heat-resistant high-speed steel cutting tools, such as... Figure 1 As shown, it includes the following steps: S1: Pickling and Cleaning The high-speed steel substrate was placed in a vacuum chamber and preheated at 65°C for 35 minutes. Then it was immersed in a water-based pickling solution, ensuring that the water-based pickling solution completely submerged the high-speed steel substrate. Finally, it was treated with 50kHz ultrasound for 8 minutes. In the last 2 minutes of pickling, the high-speed steel workpiece is connected to a pulsed current, set as the cathode of the pulsed current, and a pulsed current with a density of 15mA / cm² and a pulse frequency of 100Hz is applied. Finally, it is taken out of the water-based pickling solution, rinsed twice with ultrapure water mixed with oxygen, and air-dried to obtain the treated high-speed steel tool substrate.

[0024] The preparation process of water-based pickling solution is as follows: Measure 825 parts by mass of deionized water and pour it into the reactor. Place the reactor on a magnetic stirrer and start stirring at 350 r / min. Weigh 15 parts by mass of aminosulfonic acid and slowly add it to the deionized water while stirring continuously. After it is completely dissolved, weigh 5 parts by mass of citric acid and add it to the reactor while stirring. Stir until it is completely dissolved and the solution is clear. Adjust the magnetic stirrer speed to 550 r / min, weigh 0.3 parts by mass of cerium sulfate, add the cerium sulfate powder to the reactor, weigh 1 part by mass of hydroxyurea, add the hydroxyurea to the reactor, and stir until completely dissolved; Add 0.04 parts by weight of fluorocarbon surfactant and 0.08 parts by weight of alkynol corrosion inhibitor, stir at 550 r / min for 20 minutes to obtain water-based pickling solution.

[0025] S2: Multi-layer gradient deposition Cr and FeSiB targets are turned on, and Cr-FeSiB is deposited in a pure Ar atmosphere to magnetron sputter Cr-FeSiB as a base layer on a high-speed steel tool substrate to obtain a tool with a base layer. Keep the FeSiB target at low power, turn on the TiAl and SiC targets, and introduce a mixed gas of N2 and CH4 with a volume ratio of N2 to CH4 of 4.5:1. At the same time, turn off the FeSiB target to form a TiAlCN-SiC transition layer on the bottom layer tool, thus obtaining the transition layer tool. With the SiC target turned off, the graphene composite target embedded with Y2O3 was turned on and co-sputtered with the TiAl target to deposit the final Y2O3-TiAlCN host layer in an Ar / N2 atmosphere. The volume ratio of Ar to N2 in the Ar / N2 atmosphere was 3.5:1, resulting in a fatigue-resistant and heat-resistant high-speed steel cutting tool.

[0026] The thickness of the Cr-FeSiB underlayer is 0.5 μm, the thickness of the TiAlCN-SiC transition layer is 3 μm, and the thickness of the Y2O3-TiAlCN main layer is 6 μm.

[0027] Example 3: A fatigue-resistant and heat-resistant high-speed steel cutting tool includes a high-speed steel cutting tool substrate and a Cr-FeSiB base layer, a TiAlCN-SiC transition layer and a Y2O3-TiAlCN main layer sequentially magnetron sputtered on the surface of the high-speed steel cutting tool substrate from the inside to the outside. The high-speed steel cutting tool substrate is M2. In the Cr-FeSiB base layer, the atomic ratios of Cr, Fe, Si, and B, expressed as percentages, are 70%, 24%, 5%, and 1%, respectively. In the TiAlCN-SiC transition layer, the atomic ratios of Ti, Al, C, N, and Si, expressed as percentages, are 15%, 60%, 10%, 10%, and 5%, respectively. In the Y2O3-TiAlCN host layer, the atomic percentages of Y, O, Ti, Al, C, and N are 2%, 3%, 40%, 30%, 15%, and 10%, respectively.

[0028] A method for preparing fatigue-resistant and heat-resistant high-speed steel cutting tools, such as... Figure 1 As shown, it includes the following steps: S1: Pickling and Cleaning The high-speed steel substrate was placed in a vacuum chamber and preheated at 70°C for 40 minutes. Then it was immersed in a water-based pickling solution, ensuring that the water-based pickling solution completely submerged the high-speed steel substrate. Finally, it was treated with 60kHz ultrasound for 10 minutes. In the last 2 minutes of pickling, the high-speed steel workpiece is connected to a pulsed current, set as the cathode of the pulsed current, and a pulsed current with a density of 20mA / cm² and a pulse frequency of 100Hz is applied. Finally, it is taken out of the water-based pickling solution, rinsed 3 times with ultrapure water mixed with oxygen, and air-dried to obtain the treated high-speed steel tool substrate.

[0029] The preparation process of water-based pickling solution is as follows: Measure 850 parts by mass of deionized water and pour it into the reactor. Place the reactor on a magnetic stirrer and start stirring at 400 r / min. Weigh 20 parts by mass of aminosulfonic acid and slowly add it to the deionized water while stirring continuously. After it is completely dissolved, weigh 6 parts by mass of citric acid and add it to the reactor while stirring. Stir until it is completely dissolved and the solution is clear. Adjust the magnetic stirrer speed to 600 r / min, weigh 0.4 parts by mass of cerium sulfate, add the cerium sulfate powder to the reactor, weigh 1.5 parts by mass of hydroxyurea, add the hydroxyurea to the reactor, and stir until completely dissolved; Add 0.05 parts by mass of fluorocarbon surfactant and 1 part by mass of alkynol corrosion inhibitor, stir at 600 r / min for 30 minutes to obtain water-based pickling solution.

[0030] S2: Multi-layer gradient deposition Cr and FeSiB targets are turned on, and Cr-FeSiB is deposited in a pure Ar atmosphere to magnetron sputter Cr-FeSiB as a base layer on a high-speed steel tool substrate to obtain a tool with a base layer. Keep the FeSiB target at low power, turn on the TiAl and SiC targets, and introduce a mixed gas of N2 and CH4 with a volume ratio of 5:1. At the same time, turn off the FeSiB target to form a TiAlCN-SiC transition layer on the bottom layer tool to obtain the transition layer tool. With the SiC target turned off, the graphene composite target embedded with Y2O3 was turned on and co-sputtered with the TiAl target to deposit the final Y2O3-TiAlCN host layer in an Ar / N2 atmosphere. The volume ratio of Ar to N2 in the Ar / N2 atmosphere was 4:1, resulting in a fatigue-resistant and heat-resistant high-speed steel cutting tool.

[0031] The thickness of the Cr-FeSiB underlayer is 1 μm, the thickness of the TiAlCN-SiC transition layer is 5 μm, and the thickness of the Y2O3-TiAlCN main layer is 10 μm.

[0032] Comparative Example 1: Compared with Example 1, the difference of Comparative Example 1 is that aminosulfonic acid is not added in step S1, but citric acid is replaced by an equal mass of aminosulfonic acid. The other steps remain unchanged, and it is referred to as Comparative Example 1.

[0033] Comparative Example 2: Compared with Example 1, the difference of Comparative Example 2 is that citric acid is not added in step S1, but citric acid is replaced by aminosulfonic acid in equal mass. The other steps remain unchanged, and it is referred to as Comparative Example 2.

[0034] The surface contact angles before and after step S1 in Examples 1-3 and Comparative Examples 1-2 were tested, and the results are shown in Table 1.

[0035] Table 1

[0036] As can be seen from Table 1, in Example 1-3, a compound system of aminosulfonic acid and citric acid was used in step S1. The surface contact angle after pickling was significantly reduced from about 79° to about 68°, indicating that the contaminants were effectively removed and the surface wettability was improved, providing a cleaner active surface for subsequent coating bonding.

[0037] The contact angles of Comparative Example 1 (citric acid only) and Comparative Example 2 (sulfamic acid only) decreased significantly, only to 74.1° and 75.2°, respectively. This indicates that the cleaning effect of a single pickling component is far inferior to that of a compound system, possibly due to insufficient complexing ability or residual oxide layer.

[0038] It should be understood that those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Parts not described in detail in this specification are prior art known to those skilled in the art.

Claims

1. A fatigue-resistant and heat-resistant high-speed steel cutting tool, characterized in that, It includes a high-speed steel tool substrate and, from the inside out, a Cr-FeSiB base layer, a TiAlCN-SiC transition layer, and a Y2O3-TiAlCN main layer, which are sequentially magnetron sputtered onto the surface of the high-speed steel tool substrate. In the Cr-FeSiB base layer, the atomic ratios of Cr, Fe, Si, and B, expressed as percentages, are 60-70%, 20-25%, 5-10%, and 1-5%, respectively. In the TiAlCN-SiC transition layer, the atomic ratios of Ti, Al, C, N, and Si, expressed as percentages, are 15-20%, 50-60%, 10-15%, 10-15%, and 1-5%, respectively. In the Y2O3-TiAlCN host layer, the atomic percentages of Y, O, Ti, Al, C and N are 0.5-2%, 1-3%, 30-40%, 30-40%, 15-20%, and 10-15%, respectively.

2. The fatigue-resistant and heat-resistant high-speed steel cutting tool according to claim 1, characterized in that, The high-speed steel tool base is one of M2, M35 or M42.

3. A method for preparing a fatigue-resistant and heat-resistant high-speed steel cutting tool according to claim 2, characterized in that, Includes the following steps: S1: Pickling and Cleaning The high-speed steel tool substrate is subjected to pickling, pulse current connection and cleaning to obtain the treated high-speed steel tool substrate; S2: Multi-layer gradient deposition Cr and FeSiB targets are turned on, and Cr-FeSiB is deposited in a pure Ar atmosphere to magnetron sputter Cr-FeSiB as a base layer on a high-speed steel tool substrate to obtain a tool with a base layer. Keep the FeSiB target at low power, turn on the TiAl and SiC targets, and introduce a mixture of N2 and CH4 gas, while turning off the FeSiB target. This forms a TiAlCN-SiC transition layer on the bottom layer tool, resulting in a transition layer tool. The SiC target is turned off, and the graphene composite target embedded with Y2O3 is turned on. The target is co-sputtered with the TiAl target to deposit the final Y2O3-TiAlCN host layer in an Ar / N2 atmosphere, thus obtaining a fatigue-resistant and heat-resistant high-speed steel tool. The volume ratio of Ar to N2 in the Ar / N2 atmosphere is (3-4):

1.

4. The method for preparing a fatigue-resistant and heat-resistant high-speed steel cutting tool according to claim 3, characterized in that, The thickness of the Cr-FeSiB underlayer is 0.1-1 μm, the thickness of the TiAlCN-SiC transition layer is 1-5 μm, and the thickness of the Y2O3-TiAlCN main layer is 2-10 μm.

5. The method for preparing a fatigue-resistant and heat-resistant high-speed steel cutting tool according to claim 3, characterized in that, Step S1 is as follows: Place the high-speed steel substrate in a vacuum chamber and preheat it to 60-70℃ for 30-40 minutes. Then immerse it in a water-based pickling solution to completely submerge the high-speed steel substrate. Finally, treat it with ultrasonic waves at 40-60kHz for 5-10 minutes. In the last 2 minutes of pickling, the high-speed steel workpiece is connected to a pulsed current, set as the cathode of the pulsed current, and a pulsed current with a density of 10-20 mA / cm² and a pulse frequency of 100 Hz is applied. Finally, it is taken out of the water-based pickling solution, rinsed 2-3 times with ultrapure water mixed with oxygen, and air-dried to obtain the treated high-speed steel tool substrate.

6. The method for preparing a fatigue-resistant and heat-resistant high-speed steel cutting tool according to claim 5, characterized in that, The preparation process of water-based pickling solution is as follows: Measure 800-850 parts by weight of deionized water and pour it into the reactor. Place the reactor on a magnetic stirrer and start stirring at a speed of 300-400 r / min. Weigh 10-20 parts by weight of aminosulfonic acid and slowly add it to the deionized water while stirring continuously. After it is completely dissolved, weigh 4-6 parts by weight of citric acid and add it to the reactor while stirring. Stir until it is completely dissolved and the solution is clear. Adjust the magnetic stirrer speed to 500-600 r / min, weigh 0.2-0.4 parts by mass of cerium sulfate, add the cerium sulfate powder to the reactor, weigh 0.75-1.5 parts by mass of hydroxyurea, add the hydroxyurea to the reactor, and stir until completely dissolved; Add 0.03-0.05 parts by weight of fluorocarbon surfactant and 0.06-1 parts by weight of alkynol corrosion inhibitor, stir at 500-600 r / min for 15-30 minutes to obtain water-based pickling solution.

7. The method for preparing a fatigue-resistant and heat-resistant high-speed steel cutting tool according to claim 3, characterized in that, In a mixture of N2 and CH4, the volume ratio of N2 to CH4 is (4-5):1.

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