Flat welding ring suitable for high-frequency induction welding

Abstract

The utility model relates to a flat welding ring suitable for high-frequency induction welding, the axial section of the flat welding ring is rectangular, a welded pipe is a round pipe which is relatively sleeved, the inner side of the flat welding ring is tightly attached to a welded inner side pipe, and the bottom surface of the flat welding ring is tightly attached to the upper plane of a welded outer side pipe. The cross sections of the inner side pipe, the outer side pipe and the flat welding ring are coaxial circular rings, and the flat welding ring seals a corresponding gap needing to be welded. The method has the characteristics of reasonable design, good welding quality, fast heat absorption and melting and the like.

Description

Technical Field

[0001] This application relates to a flat welding ring suitable for high-frequency induction welding, which is mainly applicable to induction welding between multiple pipes. Background Technology

[0002] In recent years, with the rapid development of the air conditioning and refrigeration industry, the demand for brazing materials for compressor pipelines has been increasing, and the requirements for automation and precision in brazing methods have also become higher. Artificial flame welding is widely used for welding copper to copper alloys in compressor pipelines. Its advantages, such as flexibility, material diversity, and low cost, have made it a mainstream welding method. However, with the advancement of modern technology, flame welding has also encountered problems such as high skill requirements for technicians, unstable weld quality, significant safety hazards, and environmental concerns.

[0003] Induction welding is a process in which an electric current is applied to an induction coil, heating the weld edge under the influence of the skin effect and proximity effect, melting the metal, and rapidly cooling and solidifying to form a weld. It features high welding speed, environmental friendliness, high weld strength, and ease of automation. Currently, most induction-welded compressor tubes on the market use circular copper-phosphorus welding rings. However, these rings have a small contact area with the base material, often resulting in insufficient weld tightness. In particular, the center of mass of the circular welding ring is relatively far from the gap being welded, making it difficult for the melted ring to evenly fill the corresponding gap, easily leading to poor welds. Summary of the Invention

[0004] The technical problem solved by this application is to overcome the above-mentioned deficiencies in the prior art and to provide a flat welding ring suitable for high-frequency induction welding with reasonable structural design, good welding quality and fast heat absorption and melting.

[0005] The technical solution adopted by this application to solve the above-mentioned technical problems includes: a flat welding ring suitable for high-frequency induction welding, characterized in that the axial cross-section of the flat welding ring is rectangular, and the pipes to be welded are relatively nested circular pipes, so that the inner side of the flat welding ring can be tightly attached to the inner pipe to be welded, and the bottom surface of the flat welding ring can be tightly attached to the upper plane of the outer pipe to be welded. The cross-sections of the inner pipe, the outer pipe, and the flat welding ring are all coaxial circular rings, and the center of mass of the flat welding ring is close to the gap to be welded, thus sealing the gap to be welded. When the induction heating device is working, the flat welding ring melts relatively easily and flows down to seal the upper part of the gap to be welded, resulting in good welding quality and rapid heat absorption and melting.

[0006] The flat welding ring includes an inner flat ring and an outer flat ring. The gap consists of gap one and gap two. Gap one is the inner diameter of the outer tube minus the outer diameter of the middle tube, and gap two is the inner diameter of the middle tube minus the outer diameter of the inner tube. The cross-sections of the outer tube, the middle tube, the outer flat ring, the inner flat ring, and the inner tube are all coaxial circular rings. The inner diameter of the inner flat ring minus the outer diameter of the inner tube is ≤0.1 mm. The outer diameter of the outer flat ring is larger than the outer circle of gap two. The axial cross-sections of the inner and outer flat rings are both rectangles with an axial length greater than their circumferential length. This makes the center of mass of the inner and outer flat rings relatively close to the gaps that need to be welded, and after melting, they can flow relatively easily into the gaps, thereby increasing the penetration depth.

[0007] The four corners of the axial section of the inner flat ring have identical inner flat ring chamfered corners, and the radius of the inner flat ring chamfered corners is no greater than one-quarter of the side length of any side of the rectangle formed by the axial section of the inner flat ring. Similarly, the four corners of the axial section of the outer flat ring have identical outer flat ring chamfered corners, and the radius of the outer flat ring chamfered corners is no greater than one-quarter of the side length of any side of the rectangle formed by the axial section of the outer flat ring. Through this design, the flat welding ring of this application has both an approximately rectangular axial section and circumferentially rounded transitions on the outer sides, making it easy to manufacture and less likely to cause damage.

[0008] The inner and outer flat rings are tightly fitted onto the intermediate tube.

[0009] The inner flat ring is fitted onto the middle tube, and the outer flat ring is fitted onto the outer tube.

[0010] The gap is between 1 mm and 1.4 mm, and the penetration depth of the gap is between 4 mm and 5 mm.

[0011] The second gap is between 0.1 mm and 0.3 mm, and the second gap melt depth is between 4 mm and 5 mm.

[0012] Compared with the prior art, this application has the following advantages and effects: reasonable structural design, good welding quality, and fast heat absorption and melting. Attached Figure Description

[0013] Figure 1 This is a three-dimensional schematic diagram of the inner flat ring and the outer flat ring according to an embodiment of this application.

[0014] Figure 2 This is an assembly diagram of an embodiment of this application before welding.

[0015] Figure 3 This is a schematic diagram of the structure after welding in an embodiment of this application.

[0016] Figure 4 This is another assembly diagram before welding in an embodiment of this application.

[0017] Figure 5This is an application state explosion diagram of an embodiment of this application.

[0018] Figure 6 This is a cross-sectional view of the application state in an embodiment of this application.

[0019] Figure 7 This is a schematic diagram showing the deviation of the center of mass between round and flat welded rings of the same inner diameter, mass, and height when fitted onto the same pipe.

[0020] Figure 8 This is a schematic diagram of the axial cross-section of the inner and outer flat rings in an embodiment of this application.

[0021] In the diagram: 1: Outer tube; 12: Gap 1 between the outer tube and the intermediate tube; 2: Intermediate tube; 25: Gap 2 between the intermediate tube and the inner tube; 3: Outer flat ring; 4: Inner flat ring; 41: Center of mass of the inner flat ring; 5: Inner tube; 6: Induction heating device; 7: Melting (connecting) welding material; 8: Circular welding ring; 81: Center of mass of the circular welding ring. Detailed Implementation

[0022] The present application will be further described in detail below with reference to the accompanying drawings and embodiments. The following embodiments are explanations of the present application, but the present application is not limited to the following embodiments.

[0023] See Figures 1 to 8 The embodiment of this application is a flat welding ring, including an inner flat ring 4 and an outer flat ring 3. The axial (outward cross-section of the axis) sections of the inner and outer flat rings are rectangles with rounded transitions (chamfers) at the four corners. That is, the top and bottom surfaces of the flat welding ring are both planes, and the inner and outer surfaces of the flat welding ring are both coaxial rounded surfaces. This ensures that the inner flat ring 4 is tightly attached to the inner tube 5, and the bottom surface of the inner flat ring 4 is tightly attached to the upper surface of the middle tube 2. The combination of the outer flat ring 3 and the inner flat ring 4 basically covers the gap 12 between the outer tube 1 and the middle tube 2, as well as the gap 25 between the middle tube 2 and the inner tube 5 (the cross-sections of the outer tube 1, the middle tube 2, the outer flat ring 3, the inner flat ring 4, and the inner tube 5 are all coaxial circular rings. The center of mass of the outer flat ring 3 is as close as possible to the gap 12, and the center of mass of the inner flat ring 4 is as close as possible to the gap 25. The inner diameter of the inner flat ring 4 is equal to or slightly larger than the outer diameter of the inner tube 5, and the outer diameter of the outer flat ring 3 is larger than the outer circle of the gap 25, ensuring that the outer flat ring 3 and the inner flat ring 4 can quickly and in a short distance close the gap 12 and the gap 25 when they melt). When the induction heating device 6 is working, the outer flat ring 3 melts preferentially through skin and proximity effects and flows down to seal the upper part of the gap 12 between the outer tube 1 and the middle tube 2. The heat from the outer flat ring 3, the middle tube 2, the inner tube 5, and the induction heating device 6 is conducted to the inner flat ring 4. Then the inner flat ring 4 melts and flows down to seal the upper part of the gap 25 between the middle tube 2 and the inner tube 5, quickly and in large quantities filling the gap that needs to be welded, thus completing the welding.

[0024] The inner diameter of the inner flat ring 4 minus the outer diameter of the inner tube 5 in this application is ≤0.1 mm.

[0025] The gap 12 is between 1 mm and 1.4 mm, and the penetration depth of the gap 12 is between 4 mm and 5 mm.

[0026] The gap 25 is between 0.1 mm and 0.3 mm, and the penetration depth of the gap 25 is between 4 mm and 5 mm.

[0027] The axial cross sections of the inner flat ring 4 and the outer flat ring 3 (referring to...) Figure 8 The outermost solid cross-section on one side is a rectangle with an axial length greater than its circumferential length, which makes the mass centers of the inner flat ring 4 and the outer flat ring 3 relatively close to the corresponding gap, thus relatively increasing the melting depth.

[0028] This application comprises an inner flat ring 4 and an outer flat ring 3. Both the inner and outer sides of the inner flat ring 4 and the outer flat ring 3 are annular flat surfaces, which facilitates assembly and provides a large contact area with the parts to be welded. The inner flat ring 4 and the outer flat ring 3 are made of the same material, copper-phosphorus brazing filler metal.

[0029] In use, the inner flat ring 4 can be fitted with the outer flat ring 3. One particular example is... Figure 2 As shown, the contact surfaces of the inner flat ring 4 and the outer flat ring 3 are flat, and the two flat rings have an interference fit, preventing slippage after assembly. Another example is... Figure 4 As shown, the outer diameter of the inner flat ring 4 is slightly smaller than the inner diameter of the outer flat ring 3. For example, the difference between the inner diameter of the outer flat ring 3 and the outer diameter of the inner flat ring 4 is between 0.1 mm and 0.2 mm, which allows the outer flat ring 3 to be placed directly on the upper surface of the outer tube 1, which is beneficial for rapid heat absorption and melting.

[0030] During induction welding, the outer flat ring 3 melts preferentially due to the skin and proximity effects, while the inner flat ring 4 melts after heat conduction. This design can significantly increase the contact area between the brazing filler metal, the base metal, and the heating device. At the same time, the addition of antimony increases the resistance, resulting in increased welding magnetic field energy and reduced welding time.

[0031] This embodiment uses induction welding, with uniform heating power and welding time. Welding experiments were conducted on different welding rings, and the results are shown in the table below. When using a single circular welding ring (referring to a common welding ring with a circular cross-section from the axis outward), the first defect is that the contact area between the circular welding ring and the inner tube 5 and the intermediate tube 2 is small (at most line contact), resulting in slow heat conduction. The second defect is that after the solder melts, it can flow directly into the gap between the outer tube 1, the intermediate tube 2, and the outer tube 5. However, because the circular welding ring is far from the gap 12, and the melting process may be uneven, the welding ring that melts first in some areas tends to concentrate and flow down from a certain place, forming a weld bead, while other parts are still short of material, resulting in an incomplete weld formation and a tendency to have depressions. The third defect is that the center of mass of a circular welding ring with the same inner diameter, mass, and height is shifted outward compared to a flat welding ring. See [reference needed]. Figure 7This limits the welding height (penetration depth) of gap 25 and the height H of the connection between the upper plane of the intermediate tube 2 and the molten weld material of the inner tube 5, affecting the weld strength between the inner tube 5 and the intermediate tube 2. Furthermore, the flat weld ring can have its center of mass shifted further inward by increasing its height, a feature that cannot be achieved with a circular ring due to its circular cross-section. Using a double-ring circular weld ring also presents the same problem of slow heat conduction due to the small contact area, as well as the third defect mentioned above. When using inner and outer flat welding rings in this application, the contact area between the outer flat ring 3 and the inner flat ring 4, the contact area between the outer flat ring 3 and the upper surface of the outer tube 1, and the contact area between the inner flat ring 4 and the upper surface of the inner tube 5 and the intermediate tube 2 are all significantly increased, thereby increasing the heat conduction efficiency. After the inner flat ring 4 melts, its center of mass is closer to the gap 25, making it easier to flow directly into the gap 25 and fill it more deeply and fully, thus strengthening the fixation of the inner tube 5 and the intermediate tube 2. After the outer flat ring 3 melts, its center of mass is closer to the gap 12, making it easier to flow directly into the gap 12 and fill it more deeply and fully, thus strengthening the fixation of the outer tube 1 and the intermediate tube 2.

[0032] This application has the following characteristics:

[0033] 1. Replace manual flame welding with induction welding to improve automation and reduce manual labor intensity.

[0034] 2. Replacing welding rods and round welding rings with flat welding rings increases the contact area between the welding ring and the base material, as well as between the welding ring and each other, and shortens the circumferential distance between the welding ring and the gap being welded, thereby improving welding quality and production efficiency.

Claims

1. A flat welding ring suitable for high-frequency induction welding, characterized in that: The axial cross-section of the flat welding ring is rectangular, and the pipes to be welded are relatively nested circular pipes. The inner side of the flat welding ring is tightly attached to the inner pipe to be welded, and the bottom surface of the flat welding ring is tightly attached to the upper plane of the outer pipe to be welded. The cross-sections of the inner pipe, the outer pipe, and the flat welding ring are all coaxial circular rings, and the flat welding ring closes the gap corresponding to the gap to be welded.

2. The flat welding ring suitable for high-frequency induction welding according to claim 1, characterized in that: The flat welding ring includes an inner flat ring and an outer flat ring. The axial cross-section of the inner flat ring and the outer flat ring is rectangular. The gap consists of gap one and gap two. Gap one is the inner diameter of the outer tube minus the outer diameter of the middle tube, and gap two is the inner diameter of the middle tube minus the outer diameter of the inner tube. The cross-sections of the outer tube, the middle tube, the outer flat ring, the inner flat ring, and the inner tube are all coaxial circular rings. The inner diameter of the inner flat ring minus the outer diameter of the inner tube is ≤0.1 mm, and the outer diameter of the outer flat ring is larger than the outer circle of gap two.

3. The flat welding ring suitable for high-frequency induction welding according to claim 2, characterized in that: Both the inner and outer flat rings have rectangular cross-sections with an axial length greater than their circumferential length.

4. The flat welding ring suitable for high-frequency induction welding according to claim 2, characterized in that: The four corners of the axial section of the inner flat ring all have the same inner flat ring rounded chamfer, and the radius of the inner flat ring rounded chamfer is not greater than one-quarter of the length of any side of the rectangle formed by the axial section of the inner flat ring.

5. The flat welding ring suitable for high-frequency induction welding according to claim 2, characterized in that: The four corners of the axial section of the outer flat ring have the same outer flat ring rounded chamfer, and the radius of the outer flat ring rounded chamfer is not greater than one-quarter of the length of any side of the rectangle formed by the axial section of the outer flat ring.

6. The flat welding ring suitable for high-frequency induction welding according to claim 2, characterized in that: The inner and outer flat rings are tightly fitted onto the intermediate tube.

7. The flat welding ring suitable for high-frequency induction welding according to claim 2, characterized in that: The inner flat ring is fitted onto the middle tube, and the outer flat ring is fitted onto the outer tube.

8. The flat welding ring suitable for high-frequency induction welding according to claim 2, characterized in that: The gap is between 1 mm and 1.4 mm, and the penetration depth of the gap is between 4 mm and 5 mm.

9. The flat welding ring suitable for high-frequency induction welding according to claim 2, characterized in that: The second gap is between 0.1 mm and 0.3 mm, and the second gap melt depth is between 4 mm and 5 mm.

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