A method for preparing a black wear-resistant and corrosion-resistant high-toughness modified layer on the surface of a steel material
By forming a gradient composite phase layer on the surface of steel materials through low-temperature ion nitriding and atmospheric oxidation processes, the problem of insufficient wear resistance and corrosion resistance of steel materials is solved, and efficient and environmentally friendly modified layer preparation is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- HARBIN ENG UNIV
- Filing Date
- 2023-12-01
- Publication Date
- 2026-06-19
AI Technical Summary
Existing steel materials have poor wear resistance and corrosion resistance, and surface modification methods are complex and easily cause environmental pollution.
A gradient composite phase layer is formed on the surface of steel material by low-temperature ion nitriding and post-oxidation process, including iron nitrides on the surface and a high-nitrogen αN phase inside. A dense iron oxide layer is generated by atmospheric oxidation, forming a black, wear-resistant, corrosion-resistant, and high-toughness modified layer.
It significantly improves the wear resistance and corrosion resistance of steel materials, reduces the wear rate and increases the corrosion potential, avoids environmental pollution, and simplifies the process.
Smart Images
Figure CN117660872B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a method for preparing a modified layer on the surface of steel materials. Background Technology
[0002] Steel is one of the most widely used materials, found in both military and civilian applications, such as aircraft engine blades, spacecraft shells, petrochemical pipelines, and various medical devices. However, with the development of national science and technology and the improvement of people's living standards, the shortcomings of these steel materials have become increasingly apparent. The most significant is their poor wear resistance and corrosion resistance, resulting in a short service life in various fields and a susceptibility to various failure modes.
[0003] Treating steel materials to enhance their wear resistance and corrosion resistance without affecting other properties is particularly important. Currently, the main methods for improving wear resistance and corrosion resistance include alloying, machining, and surface modification. Surface modification, a commonly used method in the metalworking field, can alter the surface properties, including wear resistance and corrosion resistance, without changing the internal structure of the workpiece.
[0004] Nitriding and post-oxidation is an emerging surface modification method. The nitriding and post-oxidation process first generates a compound layer on the material surface through nitriding or carbonitriding, and forms a thermal diffusion layer inside. Then, oxidation is performed to form a compound layer and an oxide layer on the material surface, thereby enhancing the wear resistance and corrosion resistance.
[0005] Patent CN110777323A describes a conventional gas nitrocarburizing followed by oxidation process on the surface of a metal workpiece. In the nitrocarburizing stage, the temperature is not lower than 560°C, and nitriding is carried out for at least 3 hours in a mixed atmosphere of NH3, N2, and CO2. After this stage, a bright white layer is generated on the surface of the metal workpiece. In the oxidation stage, a mixed gas of water vapor and nitrogen is used. After oxidizing at a temperature of 430–450°C for 25–35 minutes in the first stage, the temperature is raised to 520–540°C for a second stage of oxidation for 10–20 minutes, thus preparing a corrosion-resistant composite layer. However, no wear-resistant effect is provided. Patent CN108893706A describes a conventional gas nitrocarburizing and post-oxidation composite treatment process for 10# steel. First, a mixed gas of NH3, N2, and CO2 is used for nitrocarburizing at 540–600℃ for 2–4 hours. Then, a composite gas of water vapor and nitrogen is used for post-oxidation at 400–510℃ for 1–3 hours. The resulting surface hardness can reach 450 HV. 0.1The above-mentioned methods not only improve corrosion resistance and wear resistance, but also enhance corrosion resistance and wear resistance. The improvement in corrosion resistance and wear resistance is mainly due to the formation of a composite layer consisting of a bright oxide layer and an ε-phase and γ-phase nitrocarburizing layer. Gong Ming et al. (Research on Ion Nitrocarburizing Combined with Subsequent Oxidation [D]. Qingdao University of Science and Technology, 2009) used an ion nitrocarburizing process at 510–570℃ followed by oxidation at 560℃ in a hydrogen + oxygen mixed gas atmosphere to prepare a composite diffusion layer of oxide layer + compound layer + diffusion layer on 40Cr steel samples. The layer after nitrocarburizing was a compound layer containing an ε-phase and a diffusion layer containing a γ-phase. The corrosion resistance and wear resistance of this composite diffusion layer were significantly improved compared to the base material. The nitriding used above is all conventional nitriding (temperature: 510~560℃) + post-oxidation process. Conventional nitriding usually forms a bright white layer containing ε phase, which is brittle and usually needs to be removed by grinding and polishing, which increases the complexity of the process. Post-oxidation treatment often uses traditional salt bath furnace treatment, which has environmental pollution and other problems. Therefore, new composite technologies are needed to improve and upgrade the process, simplify the process, and improve the quality of the modified layer. Summary of the Invention
[0006] In order to solve the problems of poor wear and corrosion resistance of existing steel materials, as well as the complexity and pollution of steel material surface modification methods, this invention proposes a method for preparing a black wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of steel materials.
[0007] The method for preparing a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of steel materials according to the present invention is carried out according to the following steps.
[0008] I. Steel material pretreatment steps: Grind the steel material and use a cleaning agent to clean the oil stains on the surface of the steel material;
[0009] II. Low-Temperature Nitriding of Steel Materials: The steel materials pretreated in Step I are fed into an ion nitriding furnace for low-temperature nitriding treatment. The nitrogen-to-hydrogen ratio is 1:(1-4), the furnace pressure is 100-300 Pa, the nitriding temperature is 380-500℃, and the nitriding time is 4-12 h. After the holding period, the materials are cooled to room temperature in the furnace and then removed from the furnace. A gradient composite phase layer of 20-200 μm is formed on the surface of the steel materials. The gradient composite phase layer consists of iron nitrides on the surface and α-nitrides inside. N Phase composition, without brittle ε phase; α N The nitrogen content of the phase gradually decreases from the surface to the interior;
[0010] III. Oxidation of steel materials after low-temperature nitriding: The steel materials after low-temperature nitriding in step II are placed in a heating and heat preservation equipment and oxidized in an atmospheric environment at a temperature of 450-510℃ for 0.5-8 hours to generate an oxide layer of 1-2μm on the surface of the steel materials.
[0011] IV. Post-treatment of steel materials after low-temperature nitriding and post-oxidation: The steel materials post-oxidized in step three are cleaned and rust removed to obtain a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of the steel materials.
[0012] The principle and effects of this invention are as follows:
[0013] This invention first employs low-temperature ion nitriding to generate a gradient composite phase layer on the surface of a steel sample. The gradient composite phase layer consists of iron nitride γ′-Fe4N on the surface and high nitrogen content α inside. N Phase composition, α N The nitrogen content of the phase gradually decreases from the surface to the interior, and it does not contain brittle ε-Fe. 2～3 The nitrogen phase enhances the bonding between the subsequent oxide layer and the infiltrated layer, effectively preventing oxide layer detachment and improving the toughness of the composite modified layer. Furthermore, this invention employs conventional heat treatment heating and holding equipment, utilizing residual air within the furnace or introducing convective air, resulting in a high nitrogen content α-phase on the surface of the infiltrated layer. N Phase decomposition occurs, and nitrogen atoms diffuse into the material interior, thereby generating more low-nitrogen α-molecules. N This process further increases the effective hardened layer thickness of the infiltration layer, while simultaneously generating a dense Fe3O4 iron oxide layer on the surface of the steel material. Therefore, a gradient composite modified layer is formed, reducing the wear rate of the steel material by more than 88%, increasing the corrosion potential, slightly reducing the corrosion current, and increasing the corrosion polarization resistance, thus significantly improving both the wear resistance and corrosion resistance of the steel material.
[0014] Compared to conventional nitriding, the low-temperature nitriding method of this invention, due to its lower nitriding temperature, can improve the material's abrasion resistance and corrosion resistance while achieving smaller deformation and lower residual stress, and also offers advantages such as high efficiency and strong controllability. In the post-oxidation process, the equipment used in this invention is simple, using only air to complete the oxidation step and obtain a black, wear-resistant, and corrosion-resistant high-toughness modified layer. Compared to the quenching-polishing-quenching process, it does not use harmful substances such as cyanate salts, and the products of each process are non-toxic and harmless to the environment. Attached Figure Description
[0015] Figure 1 The image shows the polarization curve of the steel material after treatment in Example 1.
[0016] Figure 2 This is a wear rate diagram of the steel material treated in Example 1;
[0017] Figure 3 This is an indentation diagram of the composite modified layer of the steel material treated in Example 3;
[0018] Figure 4 This is an indentation diagram of the composite modified layer of steel material after comparative treatment. Detailed Implementation
[0019] The technical solution of the present invention is not limited to the specific embodiments listed below, but also includes any reasonable combination of the specific embodiments.
[0020] Specific Implementation Method 1: The method for preparing a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of steel materials in this implementation method is carried out according to the following steps.
[0021] I. Steel material pretreatment steps: Grind the steel material and use a cleaning agent to clean the oil stains on the surface of the steel material;
[0022] II. Low-Temperature Nitriding of Steel Materials: The steel materials pretreated in Step I are fed into an ion nitriding furnace for low-temperature nitriding treatment. The nitrogen-to-hydrogen ratio is 1:(1-4), the furnace pressure is 100-300 Pa, the nitriding temperature is 380-500℃, and the nitriding time is 4-12 h. After the holding period, the materials are cooled to room temperature in the furnace and then removed from the furnace. A gradient composite phase layer of 20-200 μm is formed on the surface of the steel materials. The gradient composite phase layer consists of iron nitrides on the surface and α-nitrides inside. N Phase composition, without brittle ε phase; α N The nitrogen content of the phase gradually decreases from the surface to the interior;
[0023] III. Oxidation of steel materials after low-temperature nitriding: The steel materials after low-temperature nitriding in step II are placed in a heating and heat preservation equipment and oxidized in an atmospheric environment at a temperature of 450-510℃ for 0.5-8 hours to generate an oxide layer of 1-2μm on the surface of the steel materials.
[0024] IV. Post-treatment of steel materials after low-temperature nitriding and post-oxidation: The steel materials post-oxidized in step three are cleaned and rust removed to obtain a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of the steel materials.
[0025] This embodiment first employs low-temperature ion nitriding to generate a gradient composite phase layer on the surface of the steel sample. The gradient composite phase layer consists of iron nitride γ′-Fe4N on the surface and high nitrogen content α inside. N Phase composition, α N The nitrogen content of the phase gradually decreases from the surface to the interior, and it does not contain brittle ε-Fe. 2～3 The nitrogen phase enhances the bonding between the subsequent oxide layer and the infiltrated layer, effectively preventing oxide layer detachment and improving the toughness of the composite modified layer. Furthermore, this embodiment employs conventional heat treatment heating and holding equipment, utilizing residual air within the furnace or introducing convective air, resulting in a high nitrogen content α-phase on the surface of the infiltrated layer. N Phase decomposition occurs, and nitrogen atoms diffuse into the material interior, thereby generating more low-nitrogen α-molecules. NThis process further increases the effective hardened layer thickness of the infiltration layer, while simultaneously generating a dense Fe3O4 iron oxide layer on the surface of the steel material. Therefore, a gradient composite modified layer is formed, reducing the wear rate of the steel material by more than 88%, increasing the corrosion potential, slightly reducing the corrosion current, and increasing the corrosion polarization resistance, thus significantly improving both the wear resistance and corrosion resistance of the steel material.
[0026] Compared to conventional nitriding, the low-temperature nitriding in this embodiment, due to its lower nitriding temperature, can improve the material's abrasion resistance and corrosion resistance while achieving smaller deformation and lower residual stress, and also offers advantages such as high efficiency and strong controllability. In the post-oxidation process, this embodiment uses simple equipment, employing only air to complete the oxidation step and obtain a black, wear-resistant, and corrosion-resistant modified layer. Compared to the quenching-polishing-quenching process, it does not use harmful substances such as cyanate salts, and the products of each process are non-toxic and harmless to the environment.
[0027] Specific Implementation Method Two: This implementation method differs from Specific Implementation Method One in that the steel material used in step one is alloy steel or carbon steel, etc.
[0028] Specific Implementation Method 3: This implementation method differs from Specific Implementation Method 1 or 2 in that the cleaning agent mentioned in step 1 is acetone or alcohol.
[0029] Specific Implementation Method Four: This implementation method differs from Specific Implementation Methods One to Three in that: in step two, the steel material undergoes low-temperature nitriding: the steel material pretreated in step one is sent into an ion nitriding furnace for low-temperature nitriding treatment, with a nitrogen-to-hydrogen ratio of 1:2, a furnace pressure of 100-300 Pa, a nitriding temperature of 380-500 °C, and a nitriding time of 4-12 h. After the heat preservation is completed, the material is cooled to room temperature with the furnace and then removed from the furnace.
[0030] Specific Implementation Method 5: This implementation method differs from Specific Implementation Methods 1 to 4 in that: in step 2, the steel material is subjected to low-temperature nitriding: the steel material after the pretreatment in step 1 is sent into an ion nitriding furnace for low-temperature nitriding treatment, the nitrogen-hydrogen ratio is 1:(1-4), the furnace pressure is 100Pa, the nitriding temperature is 380-500℃, the nitriding time is 4-12h, and after the heat preservation is completed, it is cooled to room temperature with the furnace and then taken out of the furnace.
[0031] Specific Implementation Method Six: This implementation method differs from Specific Implementation Methods One to Five in that: in step two, the steel material undergoes low-temperature nitriding: the steel material pretreated in step one is sent into an ion nitriding furnace for low-temperature nitriding treatment, with a nitrogen-to-hydrogen ratio of 1:(1-4), a furnace pressure of 100-300 Pa, a nitriding temperature of 420°C, and a nitriding time of 4 hours. After the heat preservation is completed, the material is cooled to room temperature with the furnace and then removed from the furnace.
[0032] Specific Implementation Method Seven: This implementation method differs from Specific Implementation Methods One to Six in that: Step Three: Post-oxidation of the surface of the steel material after low-temperature nitriding: The steel material after low-temperature nitriding in Step Two is placed in a heating and heat preservation device and oxidized in an atmospheric environment at a temperature of 510℃ for 0.5 to 8 hours.
[0033] Specific Implementation Method Eight: This implementation method differs from Specific Implementation Methods One to Seven in that: Step Three: Post-oxidation of the surface of the steel material after low-temperature nitriding: The steel material after low-temperature nitriding in Step Two is placed in a heating and heat preservation device and oxidized in an atmospheric environment at a temperature of 450-510℃ for 8 hours.
[0034] Specific Implementation Method Nine: This implementation method differs from Specific Implementation Methods One to Eight in that: Step Three: Post-oxidation of the surface of the steel material after low-temperature nitriding: The steel material after low-temperature nitriding in Step Two is placed in a heating and heat preservation device and oxidized in an atmospheric environment at 480°C for 4 hours.
[0035] Specific Implementation Method 10: This implementation method differs from Specific Implementation Methods 1 to 9 in that the heating and heat preservation equipment mentioned in step 3 is a tube furnace, muffle furnace, or box-type resistance furnace, etc.
[0036] Example 1:
[0037] I. Steel material pretreatment steps: Use 80#, 500#, and 1000# sandpaper to polish 30CrMnSiA in sequence, and use alcohol to clean the oil stains on the surface of the steel material;
[0038] II. Low-temperature nitriding of steel materials: The 30CrMnSiA pretreated in step one is sent into an ion nitriding furnace for low-temperature nitriding treatment. The nitrogen-hydrogen ratio is 1:3, the furnace pressure is 100Pa, the nitriding temperature is 420℃, the nitriding time is 6h, and after the heat preservation is completed, it is cooled to room temperature with the furnace and then taken out of the furnace.
[0039] III. Oxidation of steel materials after low-temperature nitriding: The steel materials after low-temperature nitriding in step II are placed in a tube furnace and oxidized at an atmospheric temperature of 510℃ for 8 hours.
[0040] IV. Post-treatment of steel materials after low-temperature nitriding and post-oxidation: The steel materials post-oxidized in step three are cleaned and rust removed to obtain a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of the steel materials.
[0041] Figure 1 This is a polarization curve of the steel material after treatment in Example 1; Figure 2 This is a wear rate diagram of the steel material after treatment in Example 1; an oxide layer was formed on the surface of the 30CrMnSiA after treatment in Example 1, and the surface appeared black; the wear rate of 30CrMnSiA in Example 1 was 1.59 × 10⁻⁶ before treatment.-6 kg / N·m decreased to 1.77×10 -7 The wear rate was reduced by 88.87% with a corrosion current of approximately 0.2V, while the corrosion potential was increased by approximately 0.2V with a corrosion current that remained essentially unchanged.
[0042] Example 2:
[0043] I. Steel material pretreatment steps: Use 80#, 500#, 1000#, 1500#, and 2000# sandpaper to polish 30CrMnSiA in sequence, and use acetone to clean the oil stains on the surface of the steel material.
[0044] II. Low-temperature nitriding of steel materials: The 30CrMnSiA pretreated in step one is sent into an ion nitriding furnace for low-temperature nitriding treatment. The nitrogen-hydrogen ratio is 1:3, the furnace pressure is 100Pa, the nitriding temperature is 420℃, the nitriding time is 4h, and after the heat preservation is completed, it is cooled to room temperature with the furnace and then taken out of the furnace.
[0045] III. Oxidation of steel materials after low-temperature nitriding: The steel materials after low-temperature nitriding in step II are placed in a tube furnace and oxidized at an atmospheric temperature of 480℃ for 4 hours.
[0046] IV. Post-treatment of steel materials after low-temperature nitriding and post-oxidation: The steel materials post-oxidized in step three are cleaned and rust removed to obtain a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of the steel materials.
[0047] In Example 2, an oxide layer was formed on the surface of the 30CrMnSiA treated with the treatment, and the surface appeared black. In Example 1, the wear rate of the 30CrMnSiA treated with the treatment was reduced by 52.38% compared with that before the treatment, and the corrosion potential was increased by about 0.2V while the corrosion current remained basically unchanged.
[0048] Example 3:
[0049] I. Steel material pretreatment steps: Use 80#, 500#, 1000#, 1500#, and 2000# sandpaper in sequence to polish 42CrMo, and use alcohol to clean the oil stains on the surface of the steel material.
[0050] II. Low-temperature nitriding of steel materials: The 42CrMo pretreated in step one is sent into an ion nitriding furnace for low-temperature nitriding treatment. The nitrogen-hydrogen ratio is 1:2, the furnace pressure is 200Pa, the nitriding temperature is 420℃, the nitriding time is 8h, and after the heat preservation is completed, it is cooled to room temperature with the furnace and then taken out of the furnace.
[0051] III. Post-oxidation of the surface of low-temperature nitrided steel materials: The steel materials after low-temperature nitriding in step II are placed in a tube furnace and oxidized in an atmospheric environment at 510℃ for 4 hours.
[0052] IV. Post-treatment of steel materials after low-temperature nitriding and post-oxidation: The steel materials post-oxidized in step three are cleaned and rust removed to obtain a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of the steel materials.
[0053] Comparative example:
[0054] The 42CrMo material was pretreated by mechanically grinding it with 80#, 500#, 1000#, 1500#, and 2000# sandpaper and polishing it with 2.5μm diamond polishing paste. The surface of the material was ultrasonically cleaned with alcohol and then dried immediately. The cleaned sample was then placed in an ion nitriding furnace, and the low-temperature nitriding process was adjusted to a nitrogen-hydrogen ratio of 1:2, a furnace pressure of 200Pa, a temperature of 540℃, and low-temperature nitriding for 8 hours. After completion, the sample was cooled with the furnace to room temperature, and then the furnace was opened to remove the stainless steel material for the post-oxidation step. The low-temperature nitrided stainless steel material was placed in a tube furnace, and gas was introduced by air convection. It was post-oxidized at 510℃ for 4 hours. At this time, an oxide layer was formed on the surface of the sample. After the sample was removed, it was derusted and cleaned, and the surface appeared black.
[0055] In Example 3, an oxide layer formed on the surface of the treated 42CrMo, resulting in a black surface; the corrosion current density of 42CrMo in Example 1 decreased from 12.09 μA / cm² before treatment. 2 Reduced to 7.902 μA / cm 2 The corrosion voltage increased from -0.545V to -0.446V; the wear rate of the treated 42CrMo in Example 1 was reduced by 41.25% compared with that before treatment.
[0056] Figure 3 This is an indentation diagram of the composite modified layer of the steel material treated in Example 3; Figure 3 It can be seen that there is no ε-phase nitriding layer in the composite modified layer of the steel material treated in Example 3, and only a few micro-cracks appeared around the indentation, indicating good toughness. Figure 4 The image shows the indentation pattern of the composite modified layer of the steel material after comparative treatment. It can be seen that the steel material after comparative treatment with the ε-phase nitriding layer has large areas of peeling around the indentation, indicating poor toughness.
[0057] Example 4:
[0058] I. Steel material pretreatment steps: Use 80#, 500#, 1000#, 1500#, and 2000# sandpaper in sequence to polish 42CrMo, and use alcohol to clean the oil stains on the surface of the steel material.
[0059] II. Low-temperature nitriding of steel materials: The 42CrMo pretreated in step one is sent into an ion nitriding furnace for low-temperature nitriding treatment. The nitrogen-hydrogen ratio is 1:2, the furnace pressure is 200Pa, the nitriding temperature is 420℃, the nitriding time is 8h, and after the heat preservation is completed, it is cooled to room temperature with the furnace and then taken out of the furnace.
[0060] III. Oxidation of steel materials after low-temperature nitriding: The steel materials after low-temperature nitriding in step II are placed in a tube furnace and oxidized at an atmospheric temperature of 480℃ for 4 hours.
[0061] IV. Post-treatment of steel materials after low-temperature nitriding and post-oxidation: The steel materials post-oxidized in step three are cleaned and rust removed to obtain a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of the steel materials.
[0062] In Example 4, an oxide layer formed on the treated 42CrMo surface, giving it a black appearance; the corrosion current density of 42CrMo in Example 1 decreased from 12.09 μA / cm² before treatment. 2 Reduced to 5.408 μA / cm 2 The corrosion voltage increased from -0.545V to -0.412V; the wear rate of the treated 42CrMo in Example 1 was reduced by 47.60% compared with that before treatment.
Claims
1. A method for preparing a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of steel materials, characterized in that: The method for preparing a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of steel materials is carried out according to the following steps. I. Steel Material Pretreatment Steps: Grind the steel material and clean the oil stains on the surface of the steel material with a cleaning agent; the steel material is alloy steel or carbon steel; II. Low-temperature nitriding of steel materials: The steel materials pretreated in step one are sent into an ion nitriding furnace for low-temperature nitriding treatment. The nitrogen-hydrogen ratio is 1:(1~4), the furnace pressure is 100~300Pa, the nitriding temperature is 380~500℃, the nitriding time is 4~12h, and after the heat preservation is completed, the materials are cooled to room temperature with the furnace and then taken out of the furnace. III. Oxidation of Steel Materials After Low-Temperature Nitriding: The steel materials after low-temperature nitriding in step II are placed in a heating and insulation equipment and oxidized at an atmospheric temperature of 450~510℃ for 0.5~8 hours to form an oxide layer on the surface of the steel materials; a gradient composite phase layer of 20~200μm is formed on the surface of the steel materials; the gradient composite phase layer consists of iron nitride γ′-Fe4N on the surface and α-nitride inside. N Phase composition, without brittle ε phase; α N The nitrogen content of the phase gradually decreases from the surface to the interior; IV. Post-treatment of steel materials after low-temperature nitriding and post-oxidation: The steel materials post-oxidized in step three are cleaned and rust removed to obtain a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of the steel materials.
2. The method for preparing a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of steel materials according to claim 1, characterized in that: The cleaning agent mentioned in step one is acetone or alcohol.
3. The method for preparing a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of steel materials according to claim 1, characterized in that: In step two, the steel material undergoes low-temperature nitriding: the steel material pretreated in step one is sent into an ion nitriding furnace for low-temperature nitriding treatment. The nitrogen-hydrogen ratio is 1:2, the furnace pressure is 100~300Pa, the nitriding temperature is 380~500℃, and the nitriding time is 4~12h. After the heat preservation is completed, the material is cooled to room temperature with the furnace and then removed from the furnace.
4. The method for preparing a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of steel materials according to claim 1, characterized in that: In step two, the steel material is subjected to low-temperature nitriding: the steel material pretreated in step one is sent into an ion nitriding furnace for low-temperature nitriding treatment. The nitrogen-hydrogen ratio is 1:(1~4), the furnace pressure is 100Pa, the nitriding temperature is 380~500℃, the nitriding time is 4~12h, and after the heat preservation is completed, it is cooled to room temperature with the furnace and then taken out of the furnace.
5. The method for preparing a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of steel materials according to claim 1, characterized in that: In step two, the steel material is subjected to low-temperature nitriding: the steel material pretreated in step one is sent into an ion nitriding furnace for low-temperature nitriding treatment. The nitrogen-hydrogen ratio is 1:(1~4), the furnace pressure is 100~300Pa, the nitriding temperature is 420℃, the nitriding time is 4h, and after the heat preservation is completed, it is cooled to room temperature with the furnace and then taken out of the furnace.
6. The method for preparing a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of steel materials according to claim 1, characterized in that: Step 3: Post-oxidation of the surface of the steel material after low-temperature nitriding: Place the steel material after low-temperature nitriding in Step 2 into a heating and heat preservation device and oxidize it in an atmospheric environment at 510℃ for 0.5~8 hours.
7. The method for preparing a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of steel materials according to claim 1, characterized in that: Step 3: Post-oxidation of the surface of the steel material after low-temperature nitriding: The steel material after low-temperature nitriding in Step 2 is placed in a heating and heat preservation device and oxidized in an atmospheric environment at a temperature of 450~510℃ for 8 hours.
8. The method for preparing a black, wear-resistant, corrosion-resistant, and high-toughness modified layer on the surface of steel materials according to claim 1, characterized in that: Step 3: Post-oxidation of the surface of the steel material after low-temperature nitriding: The steel material after low-temperature nitriding in Step 2 is placed in a heating and heat preservation device and oxidized in an atmospheric environment at 480℃ for 4 hours.
9. The method for preparing a black wear-resistant and corrosion-resistant high-toughness modified layer on the surface of a ferrous material according to claim 1, characterized in that: The heating and insulation equipment mentioned in step three is a tube furnace or a muffle furnace.