Local salt bath sulfur-nitrogen-carbon ternary co-permeation method
By using a copper protective layer in local salt bath sulfur-nitrocarbon ternary co-permeable, combined with the soaking treatment of hydrogen peroxide and ammonium chloride solution, the shortcomings of the protective layer in the co-permeable process and the safety hazards in the deplating process are solved, and a safer and more efficient local sulfur-nitrocarbon ternary co-permeable effect is achieved.
Patent Information
- Application Number
- CN202510148660.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-11
- Publication Date
- 2025-05-09
AI Technical Summary
During the local salt bath sulfur-nitrocarbon ternary co-penetration process, it is difficult for the protective layer to effectively protect the non-co-penetration areas, and the existing deplating methods have safety risks.
Copper is used as the material for the protective layer, and after co-permeation treatment, the protective layer is safely removed by soaking hydrogen peroxide and ammonium chloride solution.
Effective protection of non-co-seepage areas is achieved, and the risk of hydrogen generation and fire is avoided through a safe removal process.
Smart Images
Figure CN119956290A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of material surface treatment, in particular to a method for local salt bath sulfur-nitrogen-carbon ternary co-penetration. Background Art
[0002] Salt bath sulfur-nitrogen-carbon ternary co-penetration is a chemical heat treatment process in which sulfur, carbon and nitrogen are simultaneously infiltrated into the workpiece in a salt bath medium containing cyanide and sulfide. This process can significantly improve the wear resistance, friction reduction, anti-seizure and contact fatigue strength of the workpiece. In actual production, it is often necessary to perform local sulfur-nitrogen-carbon ternary co-penetration on the workpiece. In order to achieve local ternary co-penetration, it is necessary to plate a protective layer in the non-penetration area of the workpiece before performing salt bath sulfur-nitrogen-carbon ternary co-penetration, and remove the coating after co-penetration. In the related art, the non-penetration area of the workpiece is generally protected by plating a protective layer made of tin. However, due to the strong corrosiveness of the salt bath medium used in salt bath sulfur-nitrogen-carbon ternary co-penetration, the protective layer is often difficult to provide a good protective effect on the non-penetration area during the co-penetration process. In addition, in the related art, the method of removing the protective layer in the non-penetration area is to use a strong acid or a strong base to strip the plated protective layer, but this method will produce hydrogen during the stripping process, which is easy to cause fire in large-scale production processes and poses a safety hazard. Summary of the invention
[0003] The problem solved by the present invention is at least one of the following problems: when a workpiece is subjected to local salt bath sulfur-nitrogen-carbon ternary co-penetration, the protective layer often fails to provide a good protective effect on the non-penetrated area; how to more safely remove the protective layer from the non-penetrated area.
[0004] In order to solve the above problems, the present invention provides a method for local salt bath sulfur-nitrogen-carbon ternary permeation, comprising:
[0005] Step S1, plating a protective layer on the non-co-penetration area of the workpiece to obtain a pre-treated workpiece; wherein the material of the protective layer is copper;
[0006] Step S2, placing the pretreated workpiece in a sulfur-nitrocarburizing agent for salt bath sulfur-nitrocarburizing treatment to obtain a first intermediate workpiece;
[0007] Step S3, placing the first intermediate workpiece in a hydrogen peroxide solution for a first immersion treatment to obtain a second intermediate workpiece;
[0008] Step S4, placing the second intermediate workpiece in an ammonium chloride solution for a second immersion treatment to obtain a sulfur-nitrocarburized part.
[0009] Optionally, in step S1, the protective layer has a thickness of 10 μm to 20 μm.
[0010] Optionally, in step S3, the mass fraction of the hydrogen peroxide solution is 2% to 4%.
[0011] Optionally, in step S3, the first immersion treatment lasts for 10 to 15 minutes.
[0012] Optionally, in step S3, the temperature of the first immersion treatment is 35°C to 45°C.
[0013] Optionally, in step S3, the mass fraction of the ammonium chloride solution is 15% to 20%.
[0014] Optionally, in step S4, the second immersion treatment time is 30 minutes to 40 minutes.
[0015] Optionally, in step S4, the temperature of the second immersion treatment is 35°C to 45°C.
[0016] Optionally, in step S2, the temperature of the salt bath sulfur-nitrocarburizing treatment is 555°C to 575°C.
[0017] Optionally, in step S2, the salt bath sulfur-nitrogen-carbon co-diffusion treatment time is 120 min to 180 min.
[0018] Compared with the related art, the present invention coats the non-co-penetration area of the workpiece with a protective layer made of copper before the workpiece is subjected to salt bath sulfur-nitrogen-carbon ternary co-penetration treatment. The protective layer has stronger anti-corrosion performance and can stably exist during the co-penetration treatment process, thereby having a better protective effect on the non-co-penetration area, so as to achieve local sulfur-nitrogen-carbon ternary co-penetration of the workpiece. In addition, in the present invention, after the workpiece is subjected to salt bath sulfur-nitrogen-carbon ternary co-penetration treatment, the workpiece is first immersed in hydrogen peroxide to oxidize the copper in the protective layer to copper oxide, and then the workpiece is immersed in ammonium chloride solution. The ammonium chloride hydrolyzes water to produce hydrochloric acid, and the hydrochloric acid reacts with the copper oxide to generate water-soluble copper chloride, thereby achieving safe removal of the protective layer. In summary, when the workpiece is subjected to local salt bath sulfur-nitrogen-carbon ternary co-penetration using the method of the present invention, the protective layer can have a better protective effect on the non-co-penetration area, and can safely and efficiently remove the protective layer in the non-co-penetration area. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 It is a schematic diagram of the process flow of the local salt bath sulfur-nitrogen-carbon ternary permeation method. DETAILED DESCRIPTION
[0020] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although certain embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be interpreted as being limited to the embodiments described herein. On the contrary, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the drawings and embodiments of the present invention are only for exemplary purposes and are not intended to limit the scope of protection of the present invention.
[0021] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.
[0022] The term "including" and its variations used in this article are open inclusions, that is, "including but not limited to"; the term "based on" is "based at least in part on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one other embodiment"; the term "some embodiments" means "at least some embodiments"; the term "optionally" means "optional embodiments". The relevant definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in the present invention are used to distinguish different objects, rather than to describe a specific order or a primary and secondary relationship. In addition, the terms "first" and "second" are used only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, the meaning of "multiple" is two or more.
[0023] like Figure 1 As shown, a method for local salt bath sulfur-nitrogen-carbon ternary co-penetration provided by an embodiment of the present invention comprises:
[0024] Step S1, plating a protective layer on the non-co-penetration area of the workpiece to obtain a pre-treated workpiece; wherein the material of the protective layer is copper;
[0025] Step S2, placing the pretreated workpiece in a sulfur-nitrocarburizing agent for salt bath sulfur-nitrocarburizing treatment to obtain a first intermediate workpiece;
[0026] Step S3, placing the first intermediate workpiece in a hydrogen peroxide solution for a first immersion treatment to obtain a second intermediate workpiece;
[0027] Step S4, placing the second intermediate workpiece in an ammonium chloride solution for a second immersion treatment to obtain a sulfur-nitrocarburized part.
[0028] In the embodiment of the present invention, before the workpiece is subjected to salt bath sulfur-nitrogen-carbon co-penetration treatment, a protective layer made of copper is plated on the non-penetration area of the workpiece. The protective layer has stronger anti-corrosion performance and can stably exist during the co-penetration treatment process, thereby having a good protective effect on the non-penetration area, so as to achieve local sulfur-nitrogen-carbon ternary co-penetration of the workpiece. In addition, in the embodiment of the present invention, after the workpiece is subjected to salt bath sulfur-nitrogen-carbon co-penetration treatment, the workpiece is first immersed in hydrogen peroxide to oxidize the copper in the protective layer to copper oxide, and then the workpiece is immersed in ammonium chloride solution. The ammonium chloride hydrolyzes water to produce hydrochloric acid, and the hydrochloric acid reacts with the copper oxide to generate water-soluble copper chloride, thereby achieving safe removal of the protective layer. In summary, when the workpiece is subjected to local salt bath sulfur-nitrogen-carbon ternary co-penetration using the method of the embodiment of the present invention, the protective layer can have a good protective effect on the non-penetration area, and can safely and efficiently remove the protective layer in the non-penetration area.
[0029] In some embodiments of the present invention, in the step S1, the thickness of the protective layer is 10 μm to 20 μm.
[0030] In some embodiments of the present invention, in step S3, the mass fraction of the hydrogen peroxide solution is 2% to 4%.
[0031] In some embodiments of the present invention, in step S3, the time of the first immersion treatment is 10 minutes to 15 minutes, and the temperature of the first immersion treatment is 35° C. to 45° C.; thereby, the copper in the protective layer can be quickly oxidized into copper oxide.
[0032] In some embodiments of the present invention, in step S3, the mass fraction of the ammonium chloride solution is 15% to 20%.
[0033] In some embodiments of the present invention, in step S4, the time of the second immersion treatment is 30 minutes to 40 minutes; the temperature of the second immersion treatment is 35°C to 45°C; thereby, copper oxide can be quickly converted into water-soluble copper chloride, thereby achieving safe and efficient removal of the protective layer.
[0034] In some embodiments of the present invention, in step S2, the temperature of the salt bath sulfur-nitrogen-carbon co-diffusion treatment is 555° C. to 575° C.; and the time of the salt bath sulfur-nitrogen-carbon co-diffusion treatment is 120 min to 180 min.
[0035] The present invention is further described below in conjunction with specific embodiments.
[0036] Example 1
[0037] A1. A protective layer is plated on the non-co-penetration area of the workpiece to obtain a pretreated workpiece; wherein the material of the protective layer is copper; the thickness of the protective layer is 15 μm, and the material of the workpiece is 45# steel.
[0038] A2. Placing the pretreated workpiece in a sulfur-nitrocarburizing agent for salt bath sulfur-nitrocarburizing treatment to obtain a first intermediate workpiece; the temperature of the salt bath sulfur-nitrocarburizing treatment is 560° C. and the time is 150 min.
[0039] A3. Place the first intermediate workpiece in a hydrogen peroxide solution for a first immersion treatment to obtain a second intermediate workpiece; the mass fraction of the hydrogen peroxide solution is 3%, the first immersion treatment time is 12.5 minutes, and the temperature is 40°C.
[0040] A4. Place the second intermediate workpiece in an ammonium chloride solution for a second immersion treatment to obtain a sulfur-nitrogen-carbon co-diffusion part; the mass fraction of the ammonium chloride solution is 17.5%, the second immersion treatment time is 35 minutes, and the temperature is 40°C.
[0041] Example 2
[0042] A1. A protective layer is plated on the non-co-penetration area of the workpiece to obtain a pretreated workpiece; wherein the material of the protective layer is copper; the thickness of the protective layer is 10 μm, and the material of the workpiece is 45# steel.
[0043] A2. Placing the pretreated workpiece in a sulfur-nitrocarburizing agent for salt bath sulfur-nitrocarburizing treatment to obtain a first intermediate workpiece; the temperature of the salt bath sulfur-nitrocarburizing treatment is 555° C. and the time is 180 min.
[0044] A3. Place the first intermediate workpiece in a hydrogen peroxide solution for a first immersion treatment to obtain a second intermediate workpiece; the mass fraction of the hydrogen peroxide solution is 2%, the first immersion treatment time is 15 minutes, and the temperature is 45°C.
[0045] A4. Place the second intermediate workpiece in an ammonium chloride solution for a second immersion treatment to obtain a sulfur-nitrogen-carbon co-diffusion part; the mass fraction of the ammonium chloride solution is 15%, the second immersion treatment time is 40 minutes, and the temperature is 45°C.
[0046] Example 3
[0047] A1. A protective layer is plated on the non-co-penetration area of the workpiece to obtain a pretreated workpiece; wherein the material of the protective layer is copper; the thickness of the protective layer is 20 μm, and the material of the workpiece is 45# steel.
[0048] A2. Placing the pretreated workpiece in a sulfur-nitrocarburizing agent for salt bath sulfur-nitrocarburizing treatment to obtain a first intermediate workpiece; the temperature of the salt bath sulfur-nitrocarburizing treatment is 575° C. and the time is 120 min.
[0049] A3. Place the first intermediate workpiece in a hydrogen peroxide solution for a first immersion treatment to obtain a second intermediate workpiece; the mass fraction of the hydrogen peroxide solution is 4%, the first immersion treatment time is 10 minutes, and the temperature is 35°C.
[0050] A4. Place the second intermediate workpiece in an ammonium chloride solution for a second immersion treatment to obtain a sulfur-nitrogen-carbon co-diffusion part; the mass fraction of the ammonium chloride solution is 20%, the second immersion treatment time is 30 minutes, and the temperature is 35°C.
[0051] Comparative Example 1
[0052] The difference from Example 1 is that in step A1, the material of the protective layer is tin.
[0053] Comparative Example 2
[0054] A protective layer is plated on the non-co-penetration area of the workpiece to obtain a pretreated workpiece; wherein the material of the protective layer is copper; the thickness of the protective layer is 15 μm, and the material of the workpiece is 45# steel.
[0055] The pretreated workpiece is placed in a sulfur-nitrocarburizing agent for salt bath sulfur-nitrocarburizing treatment to obtain a first intermediate workpiece; the temperature of the salt bath sulfur-nitrocarburizing treatment is 560° C. and the time is 150 minutes.
[0056] The first intermediate workpiece is immersed in a hydrochloric acid aqueous solution to obtain a sulfur-nitrocarburized part; the mass fraction of the hydrochloric acid aqueous solution is 10%, the first immersion treatment time is 20 minutes, and the temperature is 40° C. Hydrogen is generated during the immersion treatment.
[0057] Experimental example
[0058] The appearance of the sulfur-nitrocarburized parts prepared in Examples 1 to 3 and Comparative Examples 1 to 2 was tested, and the results are shown in Table 1. It can be seen from Table 1 that, compared with Comparative Example 1, the protective layers in Examples 1 to 3 and Comparative Example 2 have better protective effects on the non-co-carburized area of the workpiece. The hydrogen generation during the preparation of sulfur-nitrocarburized parts in Examples 1 to 3 and Comparative Examples 1 to 2 was monitored, and the results are shown in Table 1. It can be seen from Table 1 that hydrogen was generated during the preparation of the sulfur-nitrocarburized parts in Comparative Example 2, and no hydrogen was generated during the preparation of the sulfur-nitrocarburized parts in Examples 1 to 3 and Comparative Example 1, and the preparation process was safer.
[0059] Table 1
[0060]
[0061]
[0062] Although the present invention is disclosed as above, the protection scope of the present invention is not limited thereto. Those skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention, and these changes and modifications will fall within the protection scope of the present invention.
Claims
1. A method for local salt bath sulfur-nitrogen-carbon ternary permeation, characterized in that: include: Step S1, plating a protective layer on the non-co-penetration area of the workpiece to obtain a pre-treated workpiece; wherein the material of the protective layer is copper; Step S2, placing the pretreated workpiece in a sulfur-nitrocarburizing agent for salt bath sulfur-nitrocarburizing treatment to obtain a first intermediate workpiece; Step S3, placing the first intermediate workpiece in a hydrogen peroxide solution for a first immersion treatment to obtain a second intermediate workpiece; Step S4, placing the second intermediate workpiece in an ammonium chloride solution for a second immersion treatment to obtain a sulfur-nitrocarburized part.
2. The method for local salt bath sulfur-nitrogen-carbon ternary co-penetration according to claim 1, characterized in that: In the step S1, the thickness of the protective layer is 10 μm to 20 μm.
3. The method of local salt bath sulfur-nitrogen-carbon ternary co-penetration according to claim 1, characterized in that: In step S3, the mass fraction of the hydrogen peroxide solution is 2% to 4%.
4. The method for local salt bath sulfur-nitrogen-carbon ternary co-penetration according to claim 1, characterized in that: In step S3, the first immersion treatment takes 10 to 15 minutes.
5. The method for local salt bath sulfur-nitrogen-carbon ternary co-penetration according to claim 4, characterized in that: In step S3, the temperature of the first immersion treatment is 35°C to 45°C.
6. The method for local salt bath sulfur-nitrogen-carbon ternary co-penetration according to claim 1, characterized in that: In step S3, the mass fraction of the ammonium chloride solution is 15% to 20%.
7. The method for local salt bath sulfur-nitrogen-carbon ternary co-penetration according to claim 1, characterized in that: In step S4, the second immersion treatment takes 30 to 40 minutes.
8. The method for local salt bath sulfur-nitrogen-carbon ternary co-penetration according to claim 7, characterized in that: In step S4, the temperature of the second immersion treatment is 35°C to 45°C.
9. The method for local salt bath sulfur-nitrogen-carbon ternary co-penetration according to claim 1, characterized in that: In the step S2, the temperature of the salt bath sulfur-nitrocarburizing treatment is 555°C to 575°C.
10. The method for local salt bath sulfur-nitrogen-carbon ternary co-penetration according to claim 9, characterized in that: In the step S2, the salt bath sulfur-nitrocarburizing treatment takes 120 minutes to 180 minutes.