Full penetration high frequency welded square and rectangular tube

Abstract

The utility model discloses a kind of full penetration high-frequency welding square rectangular tubes, it is related to metal pipe manufacturing technical field, including: by strip steel is curled and high-frequency welded and formed pipe body, the cross section of the pipe body is square or rectangle, with multiple side walls and corner portion, full penetration corner weld is formed at at least one corner portion of the pipe body, and inside the corner portion, integrally formed with the inner convex reinforcing gasket along the length direction of pipe body, for improving the structural strength and reliability of corner weld;The utility model provides sufficient and controllable molten metal source for high-frequency welding by prepositioning metal filler at the edge of strip steel, effectively overcomes the defect such as unmelting, slag inclusion caused by heat fluctuation or insufficient extrusion, makes corner weld realize stable, uniform full penetration one-time, greatly improves the density, strength and corrosion resistance of weld itself.

Description

Technical Field

[0001] This utility model relates to the field of metal pipe manufacturing technology, and in particular to a fully penetrated high-frequency welded square and rectangular tube. Background Technology

[0002] High-frequency welded square and rectangular tubes are widely used in building structures, machinery manufacturing, vehicle chassis, bridge railings, and other fields due to their excellent cross-sectional properties and high production efficiency. The production process typically involves cold-bending steel strips into square or rectangular tubes, then utilizing the skin effect and proximity effect of high-frequency current to instantly heat the metal at the tube blank's edge to a molten state, achieving welding under the action of extrusion rollers.

[0003] However, traditional high-frequency welded square and rectangular tubes face a common technical challenge: achieving stable and reliable full penetration in the corner welds is difficult. The reason is as follows: First, at the corners of rectangular tubes, the current path is concentrated, and the heat generated is intense and difficult to control, which can easily lead to overheating or incomplete welding. Second, the corners are stress concentration areas, and during the welding and extrusion process, the flow and stress state of the molten metal are complex, which can easily lead to defects such as incomplete fusion and slag inclusions. In addition, the butt joint surface formed at the corners of some traditionally formed tube blanks is a concave V-shape, which is not conducive to heat accumulation and full extrusion and fusion of molten metal.

[0004] These corner welding defects significantly reduce the overall strength of square and rectangular tubes, especially their resistance to bending, torsion, and fatigue, posing a potential threat to structural safety. Although these defects can be improved through subsequent welding repairs or special heat treatments, this increases production costs and process complexity.

[0005] Therefore, there is an urgent need for an innovative solution that can address the above problems by starting with the welding structure itself and ensuring high-quality full penetration at the corners of square and rectangular tubes. Utility Model Content

[0006] To achieve the above objectives, this utility model provides a fully penetrated high-frequency welded square and rectangular tube. The utility model provides the following technical solution, including: The tube is formed by rolling and high-frequency welding of strip steel. The cross-section of the tube is square or rectangular, with multiple sidewalls and corners. A fully penetrated corner weld is formed at at least one corner of the tube. On the inner side of the corner, an inwardly convex reinforcing liner is integrally formed along the length of the tube to improve the structural strength and reliability of the corner weld.

[0007] Furthermore, the reinforcing gasket has a triangular cross-section to guide and contain molten weld metal and optimize stress distribution.

[0008] Furthermore, the strip has metal fillers pre-placed on its two side edges at positions corresponding to the corners after forming, to provide additional molten metal during high-frequency welding to ensure the formation of a full penetration weld and the reinforcing liner.

[0009] Furthermore, the metal filler is made of the same material as the base steel strip, which is used to ensure the metallurgical compatibility and mechanical properties of the weld zone are consistent.

[0010] Furthermore, the metal filler is fixed to the edge of the strip by rolling or welding to achieve a stable bond between the filler and the base material for subsequent forming and welding.

[0011] Furthermore, a support member is provided on the side of the reinforcing liner facing away from the corner weld, which extends into the tube body to enhance overall rigidity and resistance to deformation.

[0012] Furthermore, the end of the support member is connected to an integrally formed connecting block. The cross-section of the connecting block is triangular, and its two mutually perpendicular outer surfaces are respectively attached to the two adjacent inner sidewalls of the tube body to distribute and transmit the supporting force to the inner wall of the tube body, forming a stable triangular support structure.

[0013] Compared with the prior art, the beneficial effects achieved by this utility model are: 1. This utility model provides a sufficient and controllable source of molten metal for high-frequency welding by pre-placing metal filler at the edge of the strip steel. This effectively overcomes defects such as incomplete fusion and slag inclusions caused by heat fluctuations or insufficient extrusion, enabling stable and uniform full penetration of the corner weld in one go. This greatly improves the density, strength, and corrosion resistance of the weld itself. The one-piece molded triangular reinforcing gasket transforms the traditional line contact at the corner into surface support, not only eliminating stress concentration caused by geometric abrupt changes but also efficiently dispersing the stress at the weld to the side walls. This structure transforms the corner from a traditional weak point into a structurally strong area, significantly improving the bending, torsional, and fatigue resistance of the square and rectangular tube.

[0014] 2. This utility model constructs a stable internal triangular support frame by using support members set on the reinforcing liner and triangular connecting blocks at their ends to form surface contact with the inner wall of the pipe. This design extends local reinforcement to overall reinforcement, effectively suppressing local instability and deformation of the pipe under complex loads. It is particularly suitable for applications with large spans, heavy loads, or extremely high stiffness requirements. The core innovation of this utility model focuses on the pretreatment of the strip steel. It requires minimal modification to existing high-frequency welded pipe production lines, is easy to implement and promote, and solves process problems through optimized structural design, avoiding expensive subsequent processing and welding procedures. While improving product quality, it achieves better cost control. Attached Figure Description

[0015] The accompanying drawings are provided to further understand the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention and do not constitute a limitation thereof.

[0016] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 This is a schematic diagram of the connection structure between the steel strip and the metal filler of this utility model; Figure 3 This is a front view of the present invention.

[0017] In the diagram: 1. Pipe body; 2. Side wall; 3. Corner; 4. Corner weld; 5. Reinforcing gasket; 6. Strip steel; 7. Metal filler; 8. Support; 9. Connecting block. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this utility model. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0019] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0020] Example 1: As mentioned above, traditional high-frequency welded square and rectangular tubes suffer from inherent problems such as concentrated current at the corners, unfavorable welding due to the V-shaped opening, and complex extrusion stress, resulting in unstable penetration and susceptibility to defects in the corner welds. Therefore, please refer to... Figure 1 This embodiment provides a basic structure for a fully penetrated high-frequency welded square and rectangular tube. The square and rectangular tube includes a tube body 1 formed in one step by cold bending and rolling a single strip steel 6 and high-frequency resistance welding (HFW). The cross-section of the tube body 1 is rectangular, and it has four side walls 2 and four corners 3. The core innovation of this utility model lies in the fact that a fully penetrated corner weld 4 is formed at at least one corner 3 of the pipe body, and an inwardly protruding reinforcing pad 5 is integrally formed with the corner weld 4 on the inner side of the corner 3 along the entire length of the pipe body 1. The reinforcing pad 5 spans the inner side of the corner weld 4, and its cross-section is preferably triangular. This triangular structure can effectively guide the flow and filling of molten metal during welding, and plays a role in smoothly dispersing the corner stress to the two side walls 2 in the finished product.

[0021] Example 2: To address the problem of insufficient molten metal and poor heat control in traditional processes, which makes it difficult to achieve stable full penetration at the corners, please refer to... Figure 2 In order to achieve the structure described in Embodiment 1, this utility model provides a preferred method for strip pretreatment and welding; First, the strip steel is pre-treated. On both sides of the strip steel 6 in the width direction, protruding metal filler 7 is pre-formed by rolling (or welding). The material of the metal filler 7 is exactly the same as that of the base material of the strip steel 6, for example, Q235B steel, to ensure that the two have the same melting point and welding performance, and to ensure the metallurgical compatibility and mechanical properties of the weld area. Next, forming and welding are carried out. The pre-treated strip steel 6 is fed into the cold bending forming unit, which gradually rolls it into a rectangular tube blank. During this process, the metal fillers 7 pre-placed on both sides of the strip steel are precisely guided to the future corner 3 docking position. In this embodiment, preferably, the cross-sectional shape of the pre-formed protruding metal filler 7 is an equilateral triangle. After the strip steel is rolled into shape, the inclined surfaces of the equilateral triangle metal fillers 7 on both sides dock with each other to form a combined cross section of an isosceles right triangle. Then, the formed tube blank is passed through a high-frequency welding machine, and the docking seam is heated by the induction coil, so that the metal filler 7 and the adjacent base material edge melt rapidly. Then, sufficient pressure is applied to the molten interface by the extrusion roller, so that the molten metal filler 7 and the base metal are fully fused and crystallized, and finally the full penetration corner weld 4 and the internal reinforcing gasket 5 are formed simultaneously.

[0022] Example 3: Please refer to Figure 1 and Figure 3 Based on Embodiment 1, in order to meet the application scenarios with higher stiffness requirements, such as large-span structures and heavy machinery chassis, this embodiment provides an enhanced solution.

[0023] In this scheme, a support member 8 is provided on the side of the reinforcing gasket 5 facing away from the corner weld 4, that is, on the side facing the center of the pipe body 1. The support member 8 can be a solid metal rod or a pipe. The end of the support member 8 is connected to a connecting block 9 by welding or integral molding. The cross-section of the connecting block 9 is triangular, and its two finely machined outer surfaces are respectively in large-area surface contact and fixed connection with the two inner sidewalls adjacent to the pipe body 1. The connection method can be by fillet weld, spot welding or adhesive.

[0024] This support structure creates a stable triangular support frame inside the tube, effectively transferring the local reinforcement at the corners to the entire tube cross-section, thereby greatly enhancing the overall stiffness and deformation resistance of the rectangular tube.

[0025] The working process and principle of this utility model: In the manufacturing process of this utility model, the pre-placed metal filler 7 fundamentally solves the problems of insufficient molten metal and difficulty in heat control, ensuring the formation of a fully penetrated weld. The reinforcing liner 5 after molding transforms the fragile weld into a robust internal reinforcing rib, while the optional internal support structure further enhances the performance to a new level. When the final product is subjected to bending and torsional loads, the force flow is efficiently dispersed through the reinforcing liner 5 and the support frame, avoiding stress concentration, thus exhibiting mechanical properties and fatigue life far exceeding those of traditional square and rectangular tubes.

[0026] The parts not covered in this utility model are the same as or can be implemented using existing technologies.

[0027] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A fully penetrated high-frequency welded square and rectangular tube, comprising a tube body (1) formed by rolling and high-frequency welding of strip steel (6), wherein the cross-section of the tube body (1) is square or rectangular, and has multiple side walls (2) and corners (3), characterized in that: A fully penetrated corner weld (4) is formed at at least one corner (3) of the tube body (1), and an inwardly protruding reinforcing liner (5) is integrally formed on the inner side of the corner (3) along the length direction of the tube body (1); a support member (8) is provided on the side of the reinforcing liner (5) facing away from the corner weld (4).

2. The fully penetrated high-frequency welded square and rectangular tube according to claim 1, characterized in that: The cross-section of the reinforcing liner (5) is triangular.

3. The fully penetrated high-frequency welded square and rectangular tube according to claim 1, characterized in that: The strip (6) has metal fillers (7) pre-placed on its two sides at positions corresponding to the corners (3) after forming.

4. The fully penetrated high-frequency welded square and rectangular tube according to claim 3, characterized in that: The material of the metal filler (7) is the same as that of the strip steel (6).

5. A fully penetrated high-frequency welded square and rectangular tube according to claim 3, characterized in that: The metal filler (7) is fixed to the edge of the strip (6) by rolling or welding.

6. The fully penetrated high-frequency welded square and rectangular tube according to claim 1, characterized in that: The end of the support member (8) is connected to an integrally formed connecting block (9). The cross-section of the connecting block (9) is triangular, and its two mutually perpendicular outer surfaces are respectively attached to the two adjacent inner walls of the tube body (1).

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