Thread anti-permeation structure of workpiece in chemical heat treatment

Abstract

The utility model discloses a kind of chemical heat treatment workpiece thread anti-infiltration structures, including workpiece to be handled, stainless steel sleeve and sealing ring, the one end of workpiece to be handled includes outer thread structure, stainless steel sleeve is provided with the inner thread structure matched with the outer thread structure of workpiece to be handled, the one end of stainless steel sleeve connection after screwing with workpiece to be handled is provided with annular groove, sealing ring is set in annular groove.The utility model embodiment of a kind of chemical heat treatment workpiece thread anti-infiltration structure, by designing special stainless steel sleeve and soft metal washer combination structure, effectively prevent the processing medium infiltration workpiece thread in chemical heat treatment process, ensure the dimensional accuracy and performance stability of thread part, improve the qualified rate of workpiece chemical heat treatment, simplify anti-infiltration operation process, reduce production cost, reduce the harm to environment and human body simultaneously.

Description

Technical Field

[0001] This utility model relates to the field of chemical heat treatment technology, and in particular to a thread-proof structure for workpieces in chemical heat treatment. Background Technology

[0002] In chemical heat treatment processes, such as carburizing, nitriding, and carbonitriding, the treatment medium needs to be in full contact with the workpiece surface to achieve the desired material property changes. However, if the treatment medium seeps into the threaded parts of the workpiece, it will cause changes in thread dimensions and abnormal surface hardness, affecting the thread fitting accuracy and performance, and in severe cases, even rendering the workpiece unusable.

[0003] Currently, common methods for preventing leakage in workpiece threads during chemical heat treatment include applying anti-leakage coatings and using rubber plugs. Applying anti-leakage coatings has drawbacks such as uneven application and easy peeling after curing. Furthermore, the composition of anti-leakage coatings is complex, with some containing harmful substances, posing potential threats to operator health and the environment. When using rubber plugs, the rubber is prone to aging and deformation at high temperatures, leading to seal failure and ineffective prevention of the treatment medium from entering the threads. Summary of the Invention

[0004] In view of the aforementioned deficiencies in the prior art, the technical problem to be solved by this utility model is that existing methods for preventing seepage into workpiece threads during chemical heat treatment suffer from problems such as uneven coating application, easy peeling of the coating after curing, toxic and harmful anti-seepage coatings, and poor anti-seepage effect. This utility model provides a workpiece thread anti-seepage structure for chemical heat treatment. By designing a special combination structure of stainless steel sleeve and soft metal washer, it effectively prevents the treatment medium from seeping into the workpiece threads during chemical heat treatment, ensuring the dimensional accuracy and performance stability of the threaded parts, improving the pass rate of chemical heat treatment of workpieces, simplifying the anti-seepage operation process, reducing production costs, and simultaneously reducing harm to the environment and human health.

[0005] To achieve the above objectives, this utility model provides a thread-proof structure for workpieces in chemical heat treatment, including a workpiece to be treated, a stainless steel sleeve, and a sealing ring. One end of the workpiece to be treated includes an external thread structure, and the stainless steel sleeve is provided with an internal thread structure that matches the external thread structure of the workpiece to be treated. After the stainless steel sleeve is screwed in, the end connected to the workpiece to be treated is provided with an annular groove, and the sealing ring is disposed in the annular groove.

[0006] Furthermore, the stainless steel sleeve is designed to be made of 304 or 316 stainless steel.

[0007] Furthermore, the stainless steel sleeve has a wall thickness of 5mm and its length matches the length of the external thread structure of the workpiece to be processed.

[0008] Furthermore, the sealing ring is set as a soft metal gasket.

[0009] Furthermore, the thickness of the soft metal gasket is set to 0.5-4mm.

[0010] Furthermore, the soft metal gasket is made of copper.

[0011] Furthermore, the outer diameter of the soft metal washer is larger than the outer diameter of the annular groove, while the inner diameter of the soft metal washer is smaller than the inner diameter of the annular groove.

[0012] Furthermore, the depth of the annular groove is 1.5 mm and the width is 2 mm.

[0013] Technical effect

[0014] 1. High-efficiency seepage prevention: The seepage prevention structure of the workpiece thread in chemical heat treatment of this utility model forms a double seepage prevention barrier through the threaded fit between the stainless steel sleeve and the workpiece thread, and the sealing effect of the soft metal washer at the connection. The soft metal washer can tightly fit the surface of the connection after being compressed, effectively preventing the treatment medium from seeping into the threaded part during the chemical heat treatment process. The seepage prevention effect is significant and can greatly improve the pass rate of chemical heat treatment of workpiece.

[0015] 2. Stable performance: The stainless steel sleeve is made of high-temperature and corrosion-resistant stainless steel. Under the high temperature and processing medium environment of chemical heat treatment, it can maintain good structural stability and protective performance, continuously provide reliable protection for the threads, avoid leakage failure due to external environmental factors, and ensure the dimensional accuracy and performance stability of the workpiece threads during chemical heat treatment.

[0016] 3. Easy to operate: The assembly process of this seepage prevention structure is simple and easy to understand. No complicated operations or special tools are required. The assembly of the seepage prevention structure can be completed by simply screwing it in according to the conventional threaded connection method. This greatly simplifies the seepage prevention operation process before chemical heat treatment, improves production efficiency, and reduces labor intensity and production costs.

[0017] 4. Environmental Protection and Safety: This invention avoids the use of seepage-proof coatings and other materials containing harmful substances, reducing harm to the environment and the health of operators, and meeting the requirements of green environmental protection and safe production. Furthermore, the soft metal gaskets and stainless steel sleeves can be reused under certain conditions, further reducing production costs and resource waste.

[0018] The following will further explain the concept, specific structure and technical effects of this utility model in conjunction with the accompanying drawings, so as to fully understand the purpose, features and effects of this utility model. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of a stainless steel sleeve for preventing leakage of workpiece threads during chemical heat treatment, according to a preferred embodiment of this utility model.

[0020] Figure 2 This is a cross-sectional view of a stainless steel sleeve for preventing leakage of workpiece threads during chemical heat treatment, which is a preferred embodiment of this utility model.

[0021] Figure 3 This is a schematic diagram of a workpiece to be treated in a preferred embodiment of the present invention, showing a thread-proof structure for workpieces during chemical heat treatment.

[0022] Figure 4 This is a schematic diagram of a sealing ring for a workpiece thread anti-leakage structure in a preferred embodiment of the present invention during chemical heat treatment;

[0023] Figure 5 This is a schematic diagram of a preferred embodiment of the thread-proof structure for workpieces in chemical heat treatment according to this utility model.

[0024] Figure 6 This is a cross-sectional schematic diagram of a workpiece thread anti-seepage structure in a chemical heat treatment process, which is a preferred embodiment of this utility model. Detailed Implementation

[0025] To make the technical problems, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0026] In the following description, specific details, such as particular internal procedures and techniques, are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of the present invention. However, those skilled in the art will understand that the present invention may be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, devices, and circuits are omitted so as not to obscure the description of the present invention with unnecessary detail.

[0027] like Figure 1-6 As shown, this utility model embodiment provides a thread-proof structure for workpieces in chemical heat treatment, including a workpiece 2 to be treated, a stainless steel sleeve 1, and a sealing ring 3. One end of the workpiece 2 to be treated includes an external thread structure 21. The thread-proof structure in this utility model embodiment is designed for workpieces with external thread structures (including but not limited to bolts). In this embodiment, the stainless steel sleeve 1 is provided with a space 11 that matches the workpiece to be treated, and is provided with an internal thread structure 12 that matches the external thread structure 21 of the workpiece 2 to be treated. After the stainless steel sleeve 1 is screwed on, the end connected to the workpiece to be treated is provided with an annular groove 13, and the sealing ring 3 is disposed in the annular groove 13.

[0028] In this embodiment of the invention, the stainless steel sleeve 1 is made of 304 or 316 stainless steel. In this embodiment, 316 stainless steel is preferred, as it has excellent high-temperature resistance and corrosion resistance. Its wall thickness is rationally designed according to the workpiece dimensions and chemical heat treatment process parameters to ensure that the stainless steel sleeve will not deform or corrode under high temperature and processing medium conditions, continuously providing reliable anti-seepage protection for the threads. The wall thickness of the stainless steel sleeve is set to 5mm, and its length matches the external thread of the workpiece. Its inner wall is tapped with an internal thread 12 that matches the external thread of the workpiece. At the connection point where the inner wall of the stainless steel sleeve and the workpiece thread are screwed together, an annular groove 13 with a depth of 1.5mm and a width of 2mm is machined.

[0029] In this embodiment of the invention, the sealing ring 3 is a soft metal washer. In this embodiment, the soft metal washer is made of copper. The thickness of the soft metal washer is 0.5-4mm. The outer diameter is slightly larger than the outer diameter of the annular groove, and the inner diameter is slightly smaller than the inner diameter of the annular groove. This size design ensures that the soft metal washer is securely embedded in the annular groove and is compressed when the thread is tightened, tightly fitting the surface of the stainless steel sleeve and the workpiece thread, forming a good sealing effect. Specifically, the outer diameter being larger than the annular groove is within a tolerance range of 0.05-0.10mm, and the inner diameter being slightly smaller than the annular groove is within a tolerance range of 0.05-0.10mm.

[0030] In a preferred embodiment of this utility model, a method for preventing seepage from the threads of a workpiece during chemical heat treatment is provided, using the seepage-proof structure described above. The method includes the following steps:

[0031] The process involves machining the workpiece to be processed, specifically creating external threads. Based on the workpiece's design requirements, high-precision machining equipment is used to precisely manufacture standard-compliant external threads. Strict control is maintained over parameters such as thread profile, pitch, and diameter to ensure machining accuracy. The workpiece's dimensions are M12*1.5.

[0032] Prepare a stainless steel sleeve and tap an internal thread on its inner wall. Then, machine an annular groove at the opening of the stainless steel sleeve. Select a suitable 304 or 316 stainless steel sheet, roll it into a cylindrical shape using a rolling process, and then weld it using welding processes such as argon arc welding. After welding, grind and polish the weld to ensure a smooth and flat surface. Next, use a CNC machine tool to tap the inner wall of the stainless steel sleeve to machine an internal thread that matches the external thread of the workpiece. Machine an annular groove at the corresponding position on the inner wall of the stainless steel sleeve. The size of the annular groove is precisely designed according to the specifications of the soft metal washer to ensure that the washer can be smoothly embedded and has suitable compression space.

[0033] Prepare a soft metal washer and grind its edges. Select a soft metal sheet according to the size of the annular groove, and use a stamping die to make an annular soft metal washer. After stamping, grind the edges of the washer to remove burrs and prevent scratching the stainless steel sleeve and workpiece threads.

[0034] The processed workpiece and stainless steel sleeve are subjected to surface treatment; the processed stainless steel sleeve and workpiece are subjected to surface cleaning treatment to remove oil, impurities and other contaminants. Then, the stainless steel sleeve is passivated as needed to further improve its corrosion resistance.

[0035] Accurately embed the soft metal washer into the annular groove of the stainless steel sleeve, then screw the stainless steel sleeve onto the threaded part of the workpiece to be treated. Use a torque wrench to tighten the stainless steel sleeve to the specified torque value, allowing the soft metal washer to be fully compressed and deformed, filling the gap at the joint and forming a reliable leak-proof sealing structure. Before chemical heat treatment, install the workpiece with the leak-proof structure, and then proceed with the subsequent chemical heat treatment process.

[0036] This utility model provides a specific example to illustrate a thread-proofing structure and method for workpieces during chemical heat treatment. The workpiece to be treated has an external thread with a thread specification of M12×1.5. The stainless steel sleeve is made of 316 stainless steel with a wall thickness of 5mm. Its inner wall is tapped with an M12×1.5 internal thread that matches the external thread of the workpiece. At the connection point where the inner wall of the stainless steel sleeve and the workpiece thread are screwed together, an annular groove with a depth of 1.5mm and a width of 2mm is machined. A soft metal washer is made of pure copper with a thickness of 2mm, an outer diameter of 15mm, and an inner diameter of 13mm. The soft metal washer is embedded in the annular groove. The specific method is as follows:

[0037] 1. Machining the threads of the workpiece: Using a high-precision CNC lathe, the external threads of the workpiece are precisely machined according to the design requirements. All parameters are strictly controlled to ensure that the accuracy of the external threads meets the standards.

[0038] 2. Processing the stainless steel sleeve: Select 316 stainless steel sheet of appropriate specifications, roll it into a cylindrical shape using a rolling process, and weld it using argon arc welding. After welding, grind the weld seam to make the surface smooth and flat. Then, use a CNC machine tool to tap the inner wall of the stainless steel sleeve to process an M12×1.5 internal thread, and process an annular groove in the corresponding position.

[0039] 3. Preparation of soft metal washers: Select high-purity pure copper plates and use stamping dies to make ring-shaped soft metal washers through stamping process. After stamping, the edges of the washers are finely polished to remove burrs.

[0040] 4. Surface treatment: The processed stainless steel sleeve and the workpiece to be treated are cleaned to remove oil and impurities. Then the stainless steel sleeve is passivated to enhance its corrosion resistance.

[0041] 5. Assembly: Accurately embed the soft metal washer into the annular groove of the stainless steel sleeve, then screw the stainless steel sleeve onto the workpiece thread. Use a torque wrench to tighten the stainless steel sleeve to the specified torque value (e.g., 25 N·m), allowing the soft metal washer to be fully compressed and deformed, achieving a reliable anti-seepage seal. Afterwards, install the workpiece with the assembled anti-seepage structure into the chemical heat treatment equipment for carburizing treatment. During the treatment process, this anti-seepage structure effectively prevents the carburizing medium from penetrating into the workpiece thread, ensuring the dimensional accuracy and performance of the thread. This utility model provides a workpiece thread anti-seepage structure and method for chemical heat treatment, which is a purely mechanical anti-seepage structure, requiring no additional anti-seepage agent, simple to manufacture and operate, low in cost, and pollution-free.

[0042] The preferred embodiments of this utility model have been described in detail above. It should be understood that those skilled in the art can make numerous modifications and variations based on the concept of this utility model without creative effort. Therefore, all technical solutions that can be obtained by those skilled in the art based on the concept of this utility model through logical analysis, reasoning, or limited experimentation on the basis of existing technology should be within the scope of protection defined by the claims.

Claims

1. A leak-proof structure for workpiece threads during chemical heat treatment, characterized in that, The device includes a workpiece to be processed, a stainless steel sleeve, and a sealing ring. One end of the workpiece to be processed has an external thread structure. The stainless steel sleeve has an internal thread structure that matches the external thread structure of the workpiece to be processed. After the stainless steel sleeve is screwed on, the end connected to the workpiece to be processed has an annular groove. The sealing ring is disposed in the annular groove.

2. The anti-seepage structure for workpiece threads in chemical heat treatment as described in claim 1, characterized in that, The stainless steel sleeve is made of 304 or 316 stainless steel.

3. The anti-seepage structure for workpiece threads in chemical heat treatment as described in claim 2, characterized in that, The stainless steel sleeve has a wall thickness of 5mm and its length matches the length of the external thread structure of the workpiece to be processed.

4. The anti-seepage structure for workpiece threads in chemical heat treatment as described in claim 1, characterized in that, The sealing ring is a soft metal gasket.

5. The anti-seepage structure for workpiece threads in chemical heat treatment as described in claim 4, characterized in that, The thickness of the soft metal washer is set to 0.5-4mm.

6. The anti-seepage structure for workpiece threads in chemical heat treatment as described in claim 4, characterized in that, The soft metal washer is made of copper.

7. The anti-seepage structure for workpiece threads in chemical heat treatment as described in claim 4, characterized in that, The outer diameter of the soft metal washer is larger than the outer diameter of the annular groove, and the inner diameter of the soft metal washer is smaller than the inner diameter of the annular groove.

8. The anti-seepage structure for workpiece threads in chemical heat treatment as described in claim 5, characterized in that, The annular groove has a depth of 1.5 mm and a width of 2 mm.

9. The anti-seepage structure for workpiece threads in chemical heat treatment as described in claim 7, characterized in that, The outer diameter is larger than the size of the annular groove within a tolerance range of 0.05-0.10 mm, and the inner diameter is slightly smaller than the size of the annular groove within a tolerance range of 0.05-0.10 mm.

10. The anti-seepage structure for workpiece threads in chemical heat treatment as described in claim 1, characterized in that, The inner wall of the stainless steel sleeve is tapped with an M12×1.5 internal thread that matches the external thread of the workpiece.

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