Metal hose machining method for removing stress without heat treatment and obtained metal hose

Abstract

The invention belongs to the field of metal hose machining, and particularly relates to a metal hose machining method for removing stress without heat treatment and an obtained metal hose, and the metal hose machining method comprises the steps that 1, a corrugated pipe is manufactured through a cold forming technology; 2, the woven mesh is evenly wound on the outer side of the corrugated pipe, and it is ensured that the woven mesh is tightly attached to the corrugated pipe; 3, sleeving the outer side of the woven mesh with the processed outer retaining ring, so that the outer retaining ring, the woven mesh and the corrugated pipe are tightly combined together; step 4, welding and connecting the welding joint with the corrugated pipe, the woven mesh and the outer retaining ring by adopting a TIG (Tungsten Inert Gas) automatic welding process; in the welding process, high-temperature-resistant rubber is adopted for the parts, making contact with the corrugated pipe, the welding connector and the outer retaining ring, of the tool clamp, and tiny thermal expansion displacement is allowed to be generated during welding of a workpiece; and 5, stress relief treatment is conducted on the assembled and welded metal corrugated pipe through a vibration aging method.

Description

Technical Field

[0001] This invention relates to the field of metal hose processing, and more specifically to a method for processing metal hoses without heat treatment to relieve stress, and the resulting metal hose. Background Technology

[0002] Currently, the manufacturing process of metal flexible hoses includes multiple steps such as the fabrication of the corrugated pipe, the braided mesh, the outer buckle, and the welding of the end joints to the corrugated pipe, braided mesh, and outer buckle. However, residual stress is generally generated during the manufacturing process. The common method for removing residual stress in metal corrugated pipes is heat treatment, which eliminates residual stress through a heating and cooling process. However, heat treatment has some drawbacks, such as requiring specialized heating equipment and insulation devices, resulting in high energy consumption and cost. Heat treatment may also cause changes in the microstructure and properties of the corrugated pipe, affecting its performance. Furthermore, heat treatment processes cause environmental pollution, which does not meet the requirements of sustainable development. Summary of the Invention

[0003] In order to solve the technical problems existing in the prior art, the present invention discloses a method for processing metal hoses without heat treatment to relieve stress and the resulting metal hoses.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for processing stress-relief metal hoses without heat treatment, comprising the following steps: Step 1: The corrugated pipe is manufactured using a cold forming process; Step 2: Wrap the braided mesh evenly around the outside of the corrugated pipe, ensuring that the braided mesh fits tightly against the corrugated pipe; Step 3: Place the processed outer buckle on the outside of the woven mesh to tightly connect the outer buckle, the woven mesh, and the corrugated pipe together. Step 4: Using the TIG automatic welding process, the welded joint is welded to the corrugated pipe, braided mesh and outer buckle; and during the welding process, the parts of the tooling fixture that contact the corrugated pipe, welded joint and outer buckle are made of high temperature resistant rubber, which allows the workpiece to undergo slight thermal expansion displacement during welding. Step 5: Use vibration aging method to relieve stress on the assembled and welded metal bellows.

[0005] As a further technical solution, the cold forming process in step 1 includes roll forming or hydroforming.

[0006] As a further technical solution, the corrugated pipe in step 1 is made of stainless steel 304 or 316L.

[0007] As a further technical solution, corrugated pipes are processed using stainless steel strips with a thickness of 0.1-0.3mm.

[0008] As a further technical solution, stainless steel wire with a diameter of 0.1-0.2mm is used to process the woven mesh.

[0009] As a further technical solution, the weaving tension of the woven mesh is controlled at 5 N - 8 N.

[0010] As a further technical solution, the thickness of the outer buckle is 0.3-0.5mm.

[0011] As a further technical solution, the wall thickness of the welded joint is controlled at 0.8-1mm, and the welding current is 50A-80A.

[0012] As a further technical solution, in step 5, the metal bellows is placed on a vibration aging device, and the frequency and amplitude of the vibrator are adjusted to make the metal bellows resonate. During the resonance process, the residual stress inside the metal is released and homogenized, thereby achieving the purpose of stress removal without heat treatment.

[0013] Secondly, the present invention also provides a metal hose, which is obtained by the aforementioned heat-free stress-relief metal hose processing method.

[0014] The beneficial effects of this invention are as follows: 1. This invention employs a cold-forming process to manufacture the corrugated pipe, TIG-welded joints, braided mesh, and outer retaining rings. Simultaneously, it utilizes high-temperature resistant rubber tooling fixtures to optimize constraints and alleviate assembly stress caused by thermal expansion and contraction. Furthermore, a final step employs vibration aging technology to remove stress, avoiding the drawbacks of traditional heat treatment processes, reducing production costs, and minimizing environmental pollution. Specifically, the cold-forming process generates beneficial residual compressive stress in the corrugated pipe, improving its fatigue life and load-bearing capacity; TIG automatic welding ensures welding quality, reducing welding defects and stress concentration; and vibration aging technology effectively eliminates residual stress, improving the dimensional stability and performance of the corrugated pipe.

[0015] 2. Control the wall thickness of the welded joint, the stainless steel strip used for processing the bellows, and the outer buckle to a set thickness, making them thinner than existing technologies, thereby reducing heat input. Attached Figure Description

[0016] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0017] Figure 1This is a schematic diagram of the metal flexible hose structure disclosed in some embodiments of the present invention; Figure 2 This is a flowchart of the processing of a metal flexible hose disclosed in some embodiments of the present invention; The diagram exaggerates the spacing or dimensions between parts to show their positions; the diagram is for illustrative purposes only.

[0018] 1. Corrugated pipe; 2. Braided mesh; 3. External buckle; 4. Welded joint; Detailed Implementation It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0019] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless otherwise expressly indicated by the invention, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. For ease of description, the words "up," "down," "left," and "right" appearing in this invention only indicate that they are consistent with the up, down, left, and right directions of the accompanying drawings themselves, and do not limit the structure. They are merely for the purpose of facilitating the description of this invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0020] As described in the background section, there are shortcomings in the existing technology. In order to solve the above-mentioned technical problems, the present invention proposes a method for processing metal hoses without heat treatment to relieve stress, and the resulting metal hoses.

[0021] Example 1 In a typical embodiment of the present invention, such as Figure 1 As shown, this embodiment provides a heat-free stress-relieving metal hose, which consists of a corrugated pipe 1, a braided mesh 2, an outer buckle 3, and welded joints at both ends 4. The specific processing steps are as follows: Figure 2 As shown; Step 1: The corrugated pipe is manufactured using a cold forming process; Step 2: Wrap the braided mesh evenly around the outside of the corrugated pipe, ensuring that the braided mesh fits tightly against the corrugated pipe; Step 3: Place the processed outer buckle on the outside of the woven mesh to tightly connect the outer buckle, the woven mesh, and the corrugated pipe together. Step 4: Using the TIG automatic welding process, the welded joint is welded to the corrugated pipe, braided mesh and outer buckle; and during the welding process, the parts of the tooling fixture that contact the corrugated pipe, welded joint and outer buckle are made of high temperature resistant rubber, which allows the workpiece to undergo slight thermal expansion displacement during welding. Step 5: Use vibration aging method to relieve stress on the assembled and welded metal bellows.

[0022] The specific forming process of each step in the metal hose process is explained below; Step 1: The corrugated pipe 1 is formed using a cold forming process. Stainless steel 304 or 316L is selected as the material for the corrugated pipe 1. It should have good corrosion resistance, strength and toughness to ensure welding quality. Stainless steel strip with a thickness of 0.1-0.3mm is selected to process the corrugated pipe 1. The thickness of the stainless steel strip is thinner than that of the existing technology, thereby reducing heat input. Specifically, the cold forming process in this step can employ roll forming or hydroforming to process the metal sheet into a corrugated tube with a predetermined corrugated shape and size. In roll forming, the synergistic action of multiple sets of rollers gradually forms the corrugations on the metal sheet. Precise control of the roller shape, size, and motion parameters ensures the corrugation accuracy and quality of the tube. In hydroforming, the metal blank is placed in a specific mold, and high-pressure liquid is applied internally to cause the blank to expand uniformly and form corrugations. Strict control of the hydraulic pressure and loading speed ensures the forming quality of the corrugated tube. This cold forming process avoids the material property changes caused by high temperatures in traditional hot forming processes. Simultaneously, it generates beneficial residual compressive stress during the forming process, offsetting some of the tensile stress during use and improving the fatigue life and load-bearing capacity of the corrugated tube. Step 2: Weaving Woven Mesh 2. Woven mesh 2 is made using stainless steel wire with a diameter of 0.1-0.2mm. Specifically, an intelligent system is used to weave Woven Mesh 2, strictly controlling the weaving parameters. The spindle speed of the weaving machine is adjustable, with the spindle speed at both ends 15%-20% higher than that in the middle. The weaving tension is controlled at 5-8N. During the weaving process, a tension sensor monitors the stress in the woven mesh. When the stress fluctuation exceeds ±1N, the spindle speed is automatically adjusted to ensure the stress uniformity of the woven mesh, eliminating the need for subsequent heat treatment.

[0023] Step 3: Process the outer retaining ring 3. Select an outer retaining ring 3 with a thickness of 0.3-0.5mm. The outer retaining ring 3 can be a readily available outer retaining ring that meets the thickness requirements. Step 4: Assemble the corrugated pipe 1, braided mesh 2, and outer buckle 3 formed in Steps 1, 2, and 3 according to the design requirements. Specifically, first, evenly wrap the braided mesh 2 around the outside of the corrugated pipe 1 to ensure that the braided mesh 2 and the corrugated pipe 1 fit tightly together; then, put the processed outer buckle 3 on the outside of the braided mesh 2 so that the outer buckle 3, the braided mesh 2, and the corrugated pipe 1 are tightly combined together.

[0024] Step 4: Using TIG (Tungsten Inert Gas) automated welding process, weld joint 4 is connected to corrugated pipe 1, braided mesh 2, and outer retaining ring 3. The wall thickness of weld joint 4 is controlled within 0.8-1mm, and the welding current is between 50A and 80A. During the welding process, parameters such as welding current, voltage, welding speed, and shielding gas flow rate are strictly controlled to ensure welding quality. The TIG automated welding process has advantages such as high welding quality, aesthetically pleasing welds, and a small heat-affected zone, effectively ensuring the strength and sealing of weld joint 4 and avoiding stress concentration and material performance degradation caused by welding. This welding method uses an external gas as a shielding medium, and the metal is melted by the electric arc between the tungsten electrode and the workpiece to form a weld. During the welding process, the tungsten electrode does not melt and only serves as an electrode. At the same time, argon or helium gas is introduced through the nozzle of the welding torch for protection, and additional metal can be added as needed. After welding using this method, the welded joint 4 is subjected to visual inspection and non-destructive testing, such as ultrasonic testing and radiographic testing, to ensure that the welded joint 4 is free from defects such as cracks, porosity, and incomplete penetration.

[0025] Furthermore, during the TIG automatic welding process, the contact areas between the tooling fixture and the bellows 1, welding joint 4, and outer retaining ring 3 are made of high-temperature resistant rubber. This allows for slight thermal expansion displacement of the workpiece during welding, avoiding the "restraint stress" caused by rigid clamping. In this step, the welding tooling fixture is made of high-performance high-temperature resistant rubber, which can maintain excellent elasticity and stability in high-temperature environments. This type of tooling can provide more reasonable and flexible constraint conditions, alleviate assembly stress caused by thermal expansion and contraction, and avoid damage to the workpiece surface.

[0026] Step 5: Stress relief treatment is performed on the assembled and welded metal bellows using vibration aging technology. The metal bellows obtained in Step 4 is placed on a vibration aging device. By adjusting the frequency and amplitude of the vibrator, the metal bellows resonates. During the resonance process, the residual stress inside the metal is released and homogenized, thereby achieving stress removal without heat treatment. Vibration aging technology has advantages such as simple operation, high efficiency, low cost, and no environmental pollution, and can effectively improve the dimensional stability and performance of metal bellows.

[0027] This embodiment employs a cold forming process to manufacture the bellows 1, the TIG automatic welding joint 4, the bellows 1, the braided mesh 2, and the outer retaining ring 3. Simultaneously, high-temperature resistant rubber tooling fixtures are used to optimize constraints and alleviate assembly stress caused by thermal expansion and contraction. Furthermore, vibration aging technology is used in the final step to remove stress, avoiding the drawbacks of traditional heat treatment processes, reducing production costs, and minimizing environmental pollution. Specifically, the cold forming process generates beneficial residual compressive stress in the bellows, improving its fatigue life and load-bearing capacity; TIG automatic welding ensures welding quality, reducing welding defects and stress concentration; vibration aging technology effectively eliminates residual stress, improving the dimensional stability and performance of the bellows. Moreover, the wall thickness of the welding joint, the stainless steel strip used to process the bellows, and the outer retaining ring are controlled within a set thickness, making them thinner than existing technologies, thereby reducing heat input.

[0028] Example 2 Furthermore, this embodiment also provides a metal hose, which is manufactured using the processing technology described in Embodiment 1; since the metal hose is manufactured using the above-mentioned processing technology, it also possesses all the advantages described above.

[0029] Furthermore, in Examples 1 and 2, by precisely thinning the raw materials used for welding, the heat input during the welding process can be effectively reduced. This measure not only reduces the heat-affected zone of the base material but also suppresses welding deformation and grain coarsening, thereby improving the mechanical properties and corrosion resistance of the joint. It is particularly suitable for the manufacture of heat-sensitive materials and thin-walled structures.

[0030] In Examples 1 and 2, high-performance high-temperature resistant rubber was used to manufacture the welding fixtures, which can maintain excellent elasticity and stability in high-temperature environments. This type of fixture can provide more reasonable and flexible constraints, alleviating assembly stress caused by thermal expansion and contraction, while preventing damage to the workpiece surface. In Examples 1 and 2, a cold forming process is introduced to manufacture the corrugated pipe, replacing the traditional hot working method. This significantly improves forming accuracy and surface quality while avoiding material phase transformation and oxidation. Combined with TIG automatic welding technology, high-quality welding of connecting components is achieved, resulting in aesthetically pleasing welds with low rates of defects such as porosity and slag inclusions. Furthermore, vibration aging treatment replaces thermal aging, effectively eliminating residual stress while saving energy and reducing consumption. This not only reduces environmental pollution and energy costs associated with heat treatment but also avoids deformation and oxidation problems that may occur during thermal aging.

[0031] In Examples 1 and 2, the cold forming process of the present invention significantly improves the fatigue life and overall load-bearing capacity of the bellows under cyclic loads by introducing a controllable residual compressive stress layer on the material surface; the TIG automatic welding process, with its stable arc and precise heat input, greatly improves the consistency and reliability of welding, reduces stress concentration areas, and thus extends the service life of the components; the vibration aging technology promotes the homogenization and relaxation of residual stress through high-frequency micro-amplitude vibration, enhances the dimensional stability and deformation resistance of the bellows, and ultimately improves its comprehensive performance under complex working conditions.

[0032] Finally, it should be noted that relational terms such as first and second are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for processing stress-relieving metal hoses without heat treatment, characterized in that, Includes the following steps: Step 1: The corrugated pipe is manufactured using a cold forming process; Step 2: Wrap the braided mesh evenly around the outside of the corrugated pipe, ensuring that the braided mesh fits tightly against the corrugated pipe; Step 3: Place the processed outer buckle on the outside of the woven mesh to tightly connect the outer buckle, the woven mesh, and the corrugated pipe together. Step 4: Using the TIG automatic welding process, the welded joint is welded to the corrugated pipe, braided mesh and outer buckle; and during the welding process, the parts of the tooling fixture that contact the corrugated pipe, welded joint and outer buckle are made of high temperature resistant rubber, which allows the workpiece to undergo slight thermal expansion displacement during welding. Step 5: Use vibration aging method to relieve stress on the assembled and welded metal bellows.

2. The method for processing stress-relieved metal hoses without heat treatment as described in claim 1, characterized in that, The cold forming process in step 1 includes roll forming or hydroforming.

3. The method for processing stress-relieved metal hoses without heat treatment as described in claim 1, characterized in that, In step 1, the corrugated pipe is made of stainless steel 304 or 316L.

4. The method for processing stress-relieved metal hoses without heat treatment as described in claim 1, characterized in that, Corrugated pipes are made from stainless steel strips with a thickness of 0.1-0.3mm.

5. The method for processing stress-relieved metal hoses without heat treatment as described in claim 1, characterized in that, The weaving tension of the woven mesh is controlled between 5 N and 8 N.

6. The method for processing stress-relieved metal hoses without heat treatment as described in claim 1, characterized in that, Stainless steel wire with a diameter of 0.1-0.2mm is used to process the woven mesh.

7. The method for processing stress-relieved metal hoses without heat treatment as described in claim 1, characterized in that, The thickness of the outer buckle is 0.3-0.5mm.

8. The method for processing stress-relieved metal hoses without heat treatment as described in claim 1, characterized in that, In step 5, the wall thickness of the welded joint is controlled at 0.8-1mm, and the welding current is 50A-80A.

9. The method for processing stress-relieved metal hoses without heat treatment as described in claim 1, characterized in that, In step 5, the metal bellows is placed on a vibration aging device. By adjusting the frequency and amplitude of the vibrator, the metal bellows resonates. During the resonance process, the residual stress inside the metal is released and homogenized.

10. A metal flexible hose, characterized in that, It is obtained by the heat-free stress-relief metal hose processing method described in any one of claims 1-9.

Images