A pipe-making machine without welding marks and a pipe-making method

Abstract

The present invention relates to the technical field of pipe-making machines, and provides a pipe-making machine without weld marks and a pipe-making method, including a workbench; a roll forming mechanism with a feeding end and a discharging end, which is used to bend a sheet into a round pipe through multi-stage rolling; a welding mechanism arranged on the workbench, which is used to weld the joint of the round pipe; a waste heat recovery box located on the side of the welding mechanism away from the discharging end, the waste heat recovery box is sleeved on the round pipe, and the waste heat recovery box is used to collect the heat of the round pipe after welding; a return pipeline, one end of which is arranged on the waste heat recovery box, and the other end extends into the round pipe at the discharging end, and the return pipeline is used to preheat the round pipe to be welded. Through the above technical solution, the problem in the prior art that a large amount of heat remains after the straight seam welded pipe is welded, and if this heat cannot be dissipated in time, it may affect the quality of the weld seam and cause thermal deformation is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of pipe-making machines, and specifically, to a pipe-making machine without welding marks and a pipe-making method. Background Art

[0002] A high-frequency welded pipe machine is a mechanical device for manufacturing seamless steel pipes. It uses the electromagnetic induction and current thermal effect of high-frequency current to heat the edges of metal pipe blanks, enabling them to quickly reach the welding temperature and achieve welding. This welding method not only has high efficiency but also good welding quality because the heat is directly generated inside the metal, resulting in a fast and concentrated heating speed, which can instantly melt the metal edges to form high-quality welded joints.

[0003] A large amount of heat remains in the straight-seam welded pipe after welding because a large amount of heat energy is generated during the welding process. If this heat cannot be dissipated in time, it may affect the quality of the weld seam, causing thermal deformation and even affecting the performance of the entire pipe material. Utility Model Content

[0004] The present invention provides a pipe-making machine without welding marks and a pipe-making method, which solve the problem that a large amount of heat remains in the straight-seam welded pipe in the related art. If this heat cannot be dissipated in time, it may affect the quality of the weld seam and cause thermal deformation.

[0005] A pipe-making machine without welding marks for forming a circular pipe from a sheet includes:

[0006] A workbench;

[0007] A roll forming mechanism disposed on the workbench. The roll forming mechanism has a feeding end and a discharging end, and is used for bending the sheet into a circular pipe through multi-stage rolling;

[0008] A welding mechanism disposed on the workbench and on one side of the discharging end. The welding mechanism is used for welding the joint of the circular pipe;

[0009] A waste heat recovery box disposed on the workbench. The waste heat recovery box is located on the side of the welding mechanism away from the discharging end, and the waste heat recovery box is sleeved on the circular pipe. The waste heat recovery box is used for collecting the heat of the circular pipe after welding;

[0010] A return pipeline, one end of which is disposed on the waste heat recovery box and the other end extends into the circular pipe at the discharging end. The return pipeline is used for preheating the circular pipe to be welded.

[0011] Preferably, the roll forming mechanism includes:

[0012] Extrusion rollers, having a plurality of them, and the plurality of extrusion rollers are sequentially rotatably disposed on the workbench;

[0013] The grooving roller is rotatably arranged at the feeding end, and the grooving roller is used to extrude grooves on both sides of the plate. After the plate is bent, the grooves are located at the joint of the round pipe.

[0014] Preferably, the waste heat recovery box has round holes, the diameter of the round holes is the same as the diameter of the round pipe, the round pipe is slidably arranged and penetrates through the round holes, and further includes:

[0015] An air suction pump is arranged on the waste heat recovery box, and the air suction pump is used to transport the heat in the waste heat recovery box into the return pipeline.

[0016] Preferably, the return pipeline includes:

[0017] The first pipeline, one end of which is communicated with the air suction pump;

[0018] The branch pipeline, one end of which is communicated with the first pipeline, and the other end extends into the round pipe located at the discharging end;

[0019] The heat dissipation tank, the heat dissipation tank is communicated with the other end of the branch pipeline, and the heat dissipation tank is located in the round pipe, and the heat dissipation tank is used to heat the inner wall of the round pipe.

[0020] Preferably, the heat dissipation tank includes:

[0021] The tank body, which has a first air inlet, a second air inlet and an exhaust port;

[0022] The heat dissipation fins are arranged on the inner wall of the tank body, and the middle part of the heat dissipation fins has through holes;

[0023] The first spray pipe is arranged at the first air inlet, the first spray pipe is opposite to the through hole, and the first spray pipe is communicated with the return pipeline;

[0024] The air inlet pipe is arranged on the tank body, one end of the air inlet pipe is communicated with the outside, and the other end of the air inlet pipe is communicated with the second air inlet, and the air inlet pipe is used to transport the heat around the welding mechanism into the tank body.

[0025] Preferably, the heat dissipation tank further includes:

[0026] The annular pipe is arranged on the inner wall of the tank body, and the annular pipe is communicated with the air inlet pipe;

[0027] The impeller is rotatably arranged on the inner wall of the tank body, and the impeller is coaxially arranged with the first spray pipe, and the impeller is rotatably sleeved on the first spray pipe;

[0028] The second nozzle, there are several of them, and several of the second nozzles are arranged at intervals on the annular pipe. The second nozzles are communicated with the annular pipe, and the second nozzles are used to jet air to the impeller to drive the impeller to rotate.

[0029] Preferably, the heat dissipation fins are in a spiral shape, and the heat dissipation fins divide the inside of the tank into a spiral channel.

[0030] Preferably, it further includes:

[0031] A pressure relief pipeline, which is arranged on the tank body. The pressure relief pipeline has several pressure relief ports arranged at intervals, and several of the pressure relief ports are all communicated with the tank body;

[0032] An exhaust valve, which is arranged at one end of the pressure relief pipeline.

[0033] Preferably, it further includes:

[0034] A slag removal block, which is arranged on the workbench, and the slag removal block is used to remove the welding slag at the pipe joint.

[0035] A pipe manufacturing method includes the following steps:

[0036] S1. The sheet material enters the roll forming mechanism, and the roll forming mechanism bends the sheet material into a round pipe;

[0037] S2. The welding mechanism welds the joint of the round pipe;

[0038] S3. The waste heat recovery box collects the heat dissipated by the round pipe after welding;

[0039] S4. The return pipeline transports the heat collected by the waste heat recovery box to the place of the round pipe before welding.

[0040] The working principle and beneficial effects of the present invention are:

[0041] In the present invention, the sheet material starts from the feeding end and is bent into a round pipe through multi-stage roll forming. The round pipe reaches the welding mechanism, and the joint is quickly heated by high-frequency current and fused to form a seamless weld. After welding, the round pipe enters the waste heat recovery box, and the heat is collected and stored in the box body. The collected heat is re-injected into the round pipe to be welded through the return pipeline to achieve preheating. The preheated round pipe enters the welding cycle again, and the whole process continues until all the sheet materials are processed. Through an effective waste heat recovery and reuse system, it ensures efficient energy use during the welding process and minimizes the thermal stress after welding, thereby improving the quality of the finished steel pipe. Description of the Drawings

[0042] The following will further illustrate the above characteristics, technical features, advantages and their implementation manners of the present invention in a clear and understandable manner in combination with the accompanying drawings.

[0043] Figure 1 Schematic diagram of the overall structure of the present invention;

[0044] Figure 2 Schematic diagram of the welding mechanism structure of the present invention;

[0045] Figure 3 Schematic diagram of the radiator structure of the present invention;

[0046] Figure 4 Schematic diagram of the internal structure of the radiator of the present invention;

[0047] Figure 5 Front view of the internal structure of the radiator of the present invention;

[0048] Figure 6 Schematic diagram of the impeller structure of the present invention.

[0049] In the figure: 1, workbench; 101, feeding end; 102, discharging end; 2, plate; 3, roll forming mechanism; 301, grooving roll; 302, extrusion roll; 4, waste heat recovery box; 5, welding mechanism; 6, round pipe; 7, return pipeline; 701, first pipeline; 702, branch pipeline; 8, round hole; 9, heat dissipation tank; 901, tank body; 9011, first air inlet; 9012, second air inlet; 9013, exhaust port; 902, air inlet pipe; 903, exhaust valve; 904, pressure relief pipeline; 9041, pressure relief port; 10, suction pump; 11, impurity removal block; 12, first nozzle; 13, annular pipe; 14, impeller; 15, second nozzle; 16, heat dissipation fins; 17, spiral channel. Specific embodiments

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific embodiments of the present invention will be described below with reference to the accompanying drawings. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings, and other embodiments can also be obtained.

[0051] To make the drawings concise, only the parts related to the utility model are schematically shown in each drawing, and they do not represent the actual structure of the product. In addition, to make the drawings concise and easy to understand, in some drawings, components with the same structure or function are only schematically shown as one of them, or only one of them is marked. In this article, "one" not only means "only this one", but also can mean "more than one" situation, and "several" includes "two" and "more than two".

[0052] In this text, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "linkage" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] In addition, in the description of this application, the terms "first", "second", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0054] Refer to Figures 1 to 6 , which is an embodiment of the present invention. A tube-making machine without weld marks is proposed, which is used to make a sheet 2 into a round tube 6, and includes: a workbench 1; a roll forming mechanism 3, which is arranged on the workbench 1. The roll forming mechanism 3 has a feeding end 101 and a discharging end 102. The roll forming mechanism 3 is used to bend the sheet 2 into a round tube 6 through multi-stage roll pressing; a welding mechanism 5, which is arranged on the workbench 1 and on one side of the discharging end 102. The welding mechanism 5 is used to weld the joint of the round tube 6; a waste heat recovery box 4, which is arranged on the workbench 1. The waste heat recovery box 4 is located on the side of the welding mechanism 5 away from the discharging end 102. The waste heat recovery box 4 is sleeved on the round tube 6. The waste heat recovery box 4 is used to collect the heat of the round tube 6 after welding; a return pipeline 7, one end of which is arranged on the waste heat recovery box 4, and the other end extends into the round tube 6 at the discharging end 102. The return pipeline 7 is used to preheat the round tube 6 to be welded.

[0055] In the above solution, through an effective waste heat recovery and reuse system, the efficient energy use during the welding process and the minimization of thermal stress after welding are ensured, thereby improving the quality of the finished steel pipe. The roll forming mechanism 3 is arranged on the workbench 1 and includes a series of forming rollers arranged in a straight line, gradually bending the sheet 2 into the shape of a round pipe 6 from the feeding end 101 to the discharging end 102. The roll forming mechanism 3 ensures that the sheet 2 can pass smoothly through each roller and finally form the required size and shape of the round pipe 6. It is installed on the workbench 1, adjacent to the discharging end 102 of the roll forming mechanism 3. Using the electromagnetic induction principle of high-frequency current, the joint of the round pipe 6 is instantaneously heated to achieve seamless welding. The welding mechanism 5 needs to precisely control the current intensity and frequency to ensure the welding quality and speed. The waste heat recovery box 4 is located on the side of the welding mechanism 5 away from the discharging end 102 and can closely surround the newly welded round pipe 6. An endothermic device is provided inside the waste heat recovery box 4 to absorb the heat generated during the welding process, prevent the thermal deformation of the round pipe 6, and reduce energy waste. The waste heat recovery box 4 should also have good heat insulation performance to avoid heat dissipation to the external environment. One end of the return pipe 7 is connected to the waste heat recovery box 4, and the other end extends into the round pipe 6 to be welded. The function of the return pipe 7 is to use the recovered heat to preheat the part of the round pipe 6 that is about to enter the welding area, which can further improve the welding efficiency and quality while reducing energy consumption.

[0056] Working process: The sheet 2 starts from the feeding end 101 and is bent into a round pipe 6 through multi-stage roll forming. The round pipe 6 reaches the welding mechanism 5, and the joint is quickly heated by high-frequency current and fused to form a seamless weld. After welding, the round pipe 6 enters the waste heat recovery box 4, and the heat is collected and stored in the box. The collected heat is re-injected into the round pipe 6 to be welded through the return pipe 7 for preheating. The preheated round pipe 6 enters the welding cycle again, and the whole process continues until all the sheets 2 are processed.

[0057] Furthermore, the roll forming mechanism 3 includes: extrusion rollers 302, with several of them, and the several extrusion rollers 302 are sequentially rotatably arranged on the workbench 1; a grooving roller 301, rotatably arranged at the feeding end 101, and the grooving roller 301 is used to extrude grooves on both sides of the sheet 2. After the sheet 2 is bent, the grooves are located at the joint of the round pipe 6.

[0058] In the above solution, the extrusion roller 302 is composed of multiple independent rollers, which are arranged in sequence along the length direction of the workbench 1. Each roller has a certain inclination angle to ensure that the sheet 2 can be subjected to uniform pressure when passing through, so as to form a stable round tube 6 shape. These rollers are driven by a motor and can rotate independently or synchronously to adapt to sheets 2 of different thicknesses and materials, ensuring the stability and accuracy of the forming process. The grooving roller 301 is used to form grooves on both side edges of the sheet 2. This step occurs before the sheet 2 enters the bending process. The pressed grooves are located at both side edges of the sheet 2 and are used to make the protrusions occurring at the welding part fall into the grooves during welding, so that the surface of the round tube 6 is smooth and flat. The grooves can ensure that when the sheet 2 is bent into a round tube 6, these grooves can be accurately aligned to form the joint of the round tube 6, thus providing a flat and aligned welding surface for subsequent welding. The combined use of the grooving roller 301 and the extrusion roller 302 ensures that during the bending and forming process of the sheet 2, the joints at the edges of the material can obtain the best contact and matching state, which helps to improve the quality and efficiency of welding. In addition, by pre-forming grooves on the edges of the sheet 2, the stress concentration that may occur during the welding process can be reduced, further enhancing the mechanical properties and service life of the finished steel pipe.

[0059] Further, the waste heat recovery box 4 has a round hole 8, and the diameter of the round hole 8 is the same as the diameter of the round tube 6. The round tube 6 is slidably and penetratively arranged in the round hole 8. It further includes: an air suction pump 10, which is arranged on the waste heat recovery box 4, and the air suction pump 10 is used to transport the heat in the waste heat recovery box 4 into the return pipeline 7.

[0060] In the above solution, a round hole 8 matching the diameter of the round tube 6 is designed at the central position of the waste heat recovery box 4 to ensure that the round tube 6 can pass through smoothly without being blocked. The edge of the round hole 8 should be smooth to avoid any damage to the surface of the round tube 6 and also to retain heat to the maximum extent. The air suction pump 10 is installed on the waste heat recovery box 4, and its function is to extract air from the box body and transfer the heat in the air in the waste heat recovery box 4 to the return pipeline 7 at the same time. Usually, the inlet of the air suction pump 10 is directly aligned with the round hole 8 to capture the heat radiated from the surface of the round tube 6. A heat exchanger is designed inside the waste heat recovery box 4, or it is made of a material with good heat conduction performance to ensure that the heat can be effectively transferred from the surface of the round tube 6 to the air in the box body. The heat transfer mechanism needs to have good heat conduction performance and be able to withstand high temperatures to ensure long-term stable operation. One end of the return pipeline 7 is connected to the waste heat recovery box 4, and the other end extends into the round tube 6 to be welded. Through the action of the air suction pump 10, the heat is transferred from the waste heat recovery box 4 to the return pipeline 7 and then introduced into the round tube 6 to be welded for preheating. The return pipeline 7 should consider the uniformity of heat distribution to avoid local overheating, which may affect the structural integrity and welding quality of the round tube 6.

[0061] Operation process: After the welding of the round tube 6 is completed, during the movement of the round tube 6, through the round hole 8 of the waste heat recovery box 4, at this time, the surface of the round tube 6 still maintains a relatively high temperature. The heat exchanger inside the waste heat recovery box 4 absorbs the heat on the surface of the round tube 6 to prevent the heat from dissipating into the environment. The suction pump 10 is started to extract the hot air with heat from the waste heat recovery box 4 and transport it into the round tube 6 to be welded through the return pipeline 7. Before the round tube 6 to be welded enters the welding mechanism 5, it first receives preheating from the waste heat recovery box 4 through the return pipeline 7, thereby improving the welding efficiency and welding quality. This process is carried out cyclically to ensure that each new round tube 6 can be fully preheated before welding, and at the same time, the effective recovery and reuse of heat are realized.

[0062] Further, the return pipeline 7 includes: a first pipeline 701, one end of which is connected to the suction pump 10; a branch pipeline 702, one end of which is connected to the first pipeline 701 and the other end extends into the round tube 6 located at the discharge end 102; a heat dissipation tank 9, the heat dissipation tank 9 is connected to the other end of the branch pipeline 702, and the heat dissipation tank 9 is located inside the round tube 6, and the heat dissipation tank 9 is used to heat the inner wall of the round tube 6.

[0063] In the above solution, one end of the first pipeline 701 is tightly connected to the suction pump 10 for receiving the hot air extracted from the waste heat recovery box 4. The outer wall of the first pipeline 701 has a heat insulation layer to reduce the heat loss during transmission and ensure the efficient use of heat. The branch pipeline 702 is connected to the other end of the first pipeline 701 for dispersing and sending the heat into the round tube 6 to be welded. The branch pipeline 702 ensures that the heat can be evenly distributed in the entire internal space of the round tube 6. The heat dissipation tank 9 is located inside the round tube 6, one end of which is connected to the branch pipeline 702 and the other end extends deep into the round tube 6. Heat dissipation fins 16 are installed inside the heat dissipation tank 9 to increase the contact area with the inner wall of the round tube 6, so as to more effectively transfer the heat to the inner wall of the round tube 6. The welded round tube 6 passes through the round hole 8 of the waste heat recovery box 4, and the heat therein is absorbed by the heat exchanger in the box body. The suction pump 10 extracts the air containing heat from the waste heat recovery box 4 and transports it through the first pipeline 701. The heat reaches the branch pipeline 702 through the first pipeline 701 and then is distributed to a plurality of heat dissipation tanks 9 located inside the round tube 6. The heat dissipation tank 9 evenly transfers the heat to the round tube 6 to preheat the round tube 6.

[0064] Furthermore, the heat dissipation tank 9 includes: a tank body 901, having a first air inlet 9011, a second air inlet 9012 and an exhaust port 9013; a heat dissipation fin 16, which is arranged on the inner wall of the tank body 901, and the heat dissipation fin 16 has a through hole in the middle; a first nozzle 12, which is arranged at the first air inlet 9011, the first nozzle 12 is directly opposite to the through hole, and the first nozzle 12 is connected to the return pipe 7; an air intake pipe 902, which is arranged on the tank body 901, one end of the air intake pipe 902 is connected to the outside, and the other end of the air intake pipe 902 is connected to the second air inlet 9012, and the air intake pipe 902 is used to transfer the heat around the welding mechanism 5 to the tank body 901.

[0065] In the above scheme, the tank body 901 is the main structure of the heat dissipation tank 9, and has a first air inlet 9011, a second air inlet 9012 and an exhaust port 9013. The material of the tank body 901 should be selected from metals with good thermal conductivity, such as copper or aluminum, to ensure that heat can be transferred quickly. The heat dissipation fins 16 are arranged on the inner wall of the tank body 901, which increases the contact area between the tank body 901 and the inner wall of the circular tube 6, thereby improving the heat exchange efficiency. A through hole is designed in the middle of the heat dissipation fin 16 for direct impact of the directional hot air flow of the first nozzle 12 to ensure rapid and uniform distribution of heat. The first nozzle 12 is arranged at the first air inlet 9011, and its spraying direction is directly opposite to the through hole on the heat dissipation fin 16. The first nozzle 12 is connected to the return pipe 7, and is used to directly spray the hot air collected from the waste heat recovery box 4 onto the heat dissipation fin 16 to accelerate heat transfer. The air inlet pipe 902 is arranged on the tank body 901, one end of which is connected to the outside, especially to the high temperature area near the welding mechanism 5, and the other end is connected to the second air inlet 9012. The function of the air inlet pipe 902 is to introduce the extra heat generated during welding into the tank body 901 to increase the preheating effect.

[0066] Working process: The hot air collected from the waste heat recovery box 4 is transported to the first nozzle 12 through the return pipe 7. The first nozzle 12 directly aligns the hot air with the through holes on the heat dissipation fins 16 in a high-speed spraying manner, so that the hot air quickly diffuses and fills the entire tank body 901 and enters the deep part of the circular tube 6 from the exhaust port 9013 in the axial direction of the circular tube 6. The heat around the welding mechanism 5 is introduced into the tank body 901 through the air inlet pipe 902 as a supplementary heat source for preheating to enhance the preheating effect. This embodiment makes full use of the waste heat generated during the welding process and reduces energy waste. The heat dissipation fins 16 ensure full contact between the hot air and the inside of the tank body 901, thereby improving the heat exchange efficiency. The heat inside the tank body 901 is transferred to the inner wall of the circular tube 6 through the heat dissipation fins 16, and the circular tube 6 is preheated, thereby improving the welding efficiency and welding quality.

[0067] Further, the heat dissipation tank 9 further includes: an annular pipe 13 disposed on the inner wall of the tank body 901, and the annular pipe 13 is communicated with the air inlet pipe 902; an impeller 14 rotatably disposed on the inner wall of the tank body 901, and the impeller 14 is coaxially arranged with the first nozzle 12, and the impeller 14 is rotatably sleeved on the first nozzle 12; a plurality of second nozzles 15, and the plurality of second nozzles 15 are spaced apart on the annular pipe 13, the second nozzles 15 are communicated with the annular pipe 13, and the second nozzles 15 are used for jetting air to the impeller 14 to drive the impeller 14 to rotate.

[0068] In the above solution, the annular pipe 13 is fixed on the inner wall of the tank body 901 for the purpose of receiving the heat input from the air inlet pipe 902 and then evenly distributing it inside the tank body 901. The annular pipe is connected to the air inlet pipe 902 to ensure that the heat can be quickly and evenly transferred to all parts of the tank body 901. The impeller 14 is installed inside the tank body 901 and is coaxially arranged with the first nozzle 12, and the central axis of the impeller 14 is consistent with the jet direction of the first nozzle 12. The impeller 14 rotates under the push of the hot air flow, promoting the circulation, uniform mixing and even distribution of the heat inside the tank body 901. A plurality of second nozzles 15 are provided, and they are spaced apart on the annular pipe 13 and are communicated with the annular pipe 13. When the annular pipe 13 receives heat, the heat is ejected in the form of a high-speed air flow through the second nozzles 15, directly impacting the impeller 14 and driving the impeller 14 to rotate. The rotation of the impeller 14 drives the air flow inside the tank body 901, promoting the uniform mixing and even distribution of the heat at different positions and improving the preheating efficiency.

[0069] The heat enters the annular pipe 13 from the air inlet pipe 902 and then is ejected through a plurality of second nozzles 15. The high-speed air flow of the second nozzles 15 impacts the impeller 14, causing it to start rotating. The rotation of the impeller 14 drives the air inside the tank body 901 to form a circulating flow, promoting the mixing and even distribution of the heat. It ensures the uniformity of the heat inside the tank body 901, thereby improving the preheating effect on the circular pipe 6. Through the rotation of the impeller 14 and the circulation of the heat, the heat inside the tank body 901 can be more effectively transferred to the heat dissipation fins 16 and the inner wall of the circular pipe 6. It not only improves the welding efficiency but also ensures the consistency of the welding quality, reducing the welding defects caused by local overheating or uneven preheating.

[0070] Further, the heat dissipation fins 16 are in a spiral shape, and the heat dissipation fins 16 divide the inside of the tank body 901 to form a spiral channel 17.

[0071] In the above solution, the heat dissipation fins 16 are helical, that is, they are spirally distributed around the central axis of the tank body 901, rather than the traditional planar or vertical arrangement. The helical heat dissipation fins 16 can significantly increase the contact area with the hot air flow, and at the same time form a complex internal flow path, improving the heat exchange efficiency. The helical channel 17 formed by the separation of the helical heat dissipation fins 16 enables the hot air flow to form a helical flow pattern inside the tank body 901, which not only prolongs the residence time of the hot air flow inside the tank body 901, enhances the absorption and transfer of heat, but also promotes the full contact between the hot air flow and the inner wall of the circular tube 6, ensuring the uniformity of preheating. The hot air flow enters the tank body 901 from the first nozzle 12 and the second nozzle 15, and the rotation of the impeller 14 promotes the initial circulation of the air flow. The hot air flow flows along the helical channel 17 and makes full contact with the helical heat dissipation fins 16, and the heat is transferred to the inner wall of the circular tube 6 through the fins. The helical heat dissipation fins 16 ensure the uniform distribution of the hot air flow inside the tank body 901, avoiding the occurrence of local overheating or cold spots. The uniform distribution of heat improves the preheating effect, ensures the temperature consistency during the welding process, and thus improves the welding quality. The formation of the helical channel 17 makes the hot air flow stay inside the tank body 901 for a longer time, increasing the opportunity of heat transfer and improving the preheating efficiency. It not only saves energy, but also speeds up the production rhythm and improves the overall production efficiency.

[0072] Furthermore, it further includes: a pressure relief pipe 904, which is arranged on the tank body 901, and the pressure relief pipe 904 has a plurality of pressure relief openings 9041 arranged at intervals, and all the plurality of pressure relief openings 9041 are communicated with the tank body 901; an exhaust valve 903, which is arranged at one end of the pressure relief pipe 904.

[0073] In the above solution, the pressure relief pipe 904 is fixed on the tank body 901 and is used to adjust the pressure inside the tank body 901, prevent the accumulation of excessive pressure, and ensure the safe operation of the equipment. The pressure relief pipe 904 is provided with a plurality of pressure relief openings 9041 arranged at intervals, and these pressure relief openings 9041 are all communicated with the internal space of the tank body 901, and can quickly release the excessive pressure. The exhaust valve 903 is installed at one end of the pressure relief pipe 904 and is used to manually or automatically control the opening and closing of the pressure relief pipe 904. Before the pressure inside the tank body 901 reaches the preset safety upper limit, the exhaust valve 903 remains closed to maintain the heat and pressure environment inside the tank body 901. Once it is detected that the pressure inside the tank body 901 exceeds the set value, the exhaust valve 903 is automatically or manually opened, and the excess gas is released through the pressure relief pipe 904 to reduce the pressure inside the tank body 901 to within the safe range. The combination of the pressure relief pipe 904 and the exhaust valve 903 can effectively prevent excessive pressure caused by thermal expansion, gas accumulation or other factors, thereby avoiding potential safety accidents.

[0074] Further, it further includes: a slag removal block 11, which is arranged on the workbench 1 and is used to remove the welding slag at the pipe joint.

[0075] In the above solution, the slag removal block 11 is installed on the workbench 1, behind the welding mechanism 5 and in front of the waste heat recovery box 4, ensuring that the welding slag has been completely removed before the steel pipe enters the waste heat recovery box 4.

[0076] A pipe manufacturing method includes the following steps:

[0077] S1. The sheet 2 enters the roll forming mechanism 3, and the roll forming mechanism 3 bends the sheet 2 into a circular pipe 6;

[0078] S2. The welding mechanism 5 welds the joint of the circular pipe 6;

[0079] S3. The waste heat recovery box 4 collects the heat dissipated by the circular pipe 6 after welding;

[0080] S4. The return pipe 7 transports the heat collected by the waste heat recovery box 4 to the place of the circular pipe 6 before welding.

[0081] Specifically, first, the sheet 2 to be processed is placed at the feeding end 101 of the pipe making machine. When the sheet 2 passes through the grooving roller 301, grooves are extruded on both side edges, providing accurate alignment for subsequent welding. The sheet 2 continues to pass through the extrusion roller 302 and is gradually bent into the shape of a circular pipe 6 through multi-stage roll forming. After the circular pipe 6 is formed, the joint reaches the welding mechanism 5. The welding mechanism 5 utilizes the electromagnetic induction and current heat effect of high-frequency current to instantaneously heat the metal edge to the welding temperature to achieve seamless welding. After welding, the surface of the circular pipe 6 is still in a high-temperature state and is ready to enter the next step of waste heat recovery. The circular pipe 6 passes through the waste heat recovery box 4, and the heat exchanger in the box absorbs the heat on the surface of the circular pipe 6. The suction pump 10 pumps the hot air in the box to the return pipe 7, and the heat is reused. The return pipe 7 injects the collected heat back into the circular pipe 6 that is about to enter the welding area for preheating. The preheating process improves the welding efficiency and reduces the additional energy required for welding, achieving energy conservation. Before the waste heat recovery box 4, the circular pipe 6 passes through the slag removal block 11 to remove the welding slag that may remain during the welding process, ensuring the surface quality of the finished steel pipe.

[0082] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limitations. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A tube-making machine without weld marks, used to form a circular tube (6) from a sheet (2), comprising: A workbench (1); A roll forming mechanism (3), arranged on the workbench (1), the roll forming mechanism (3) having a feed end (101) and a discharge end (102), the roll forming mechanism (3) being used to bend the sheet (2) into a circular tube (6) through multiple stages of roll pressing; A welding mechanism (5), arranged on the workbench (1) and on one side of the discharge end (102), the welding mechanism (5) being used to weld the joint of the circular tube (6); A waste heat recovery box (4), arranged on the workbench (1), the waste heat recovery box (4) being located on the side of the welding mechanism (5) away from the discharge end (102), the waste heat recovery box (4) being sleeved on the circular tube (6), the waste heat recovery box (4) being used to collect the heat of the circular tube (6) after welding; the waste heat recovery box (4) has a round hole (8), the diameter of the round hole (8) being the same as the diameter of the circular tube (6), and the circular tube (6) sliding and passing through the round hole (8); A return pipeline (7), one end arranged on the waste heat recovery box (4), and the other end extending into the circular tube (6) at the discharge end (102), the return pipeline (7) being used to preheat the circular tube (6) to be welded; An air suction pump (10), arranged on the waste heat recovery box (4), the air suction pump (10) being used to transport the heat in the waste heat recovery box (4) into the return pipeline (7); The return pipeline (7) includes: A first pipeline (701), one end being communicated with the air suction pump (10); A branch pipeline (702), one end being communicated with the first pipeline (701), and the other end extending into the circular tube (6) at the discharge end (102); A heat dissipation tank (9), the heat dissipation tank (9) being communicated with the other end of the branch pipeline (702), and the heat dissipation tank (9) being located inside the circular tube (6), the heat dissipation tank (9) being used to heat the inner wall of the circular tube (6); The heat dissipation tank (9) includes: A tank body (901), having a first air inlet (9011), a second air inlet (9012) and an exhaust port (9013); Heat dissipation fins (16), arranged on the inner wall of the tank body (901), the middle of the heat dissipation fins (16) having a through hole, the heat dissipation fins being in a spiral shape, the heat dissipation fins (16) dividing the inside of the tank body (901) into a spiral channel (17); A first nozzle (12), arranged at the first air inlet (9011), the first nozzle (12) facing the through hole, the first nozzle (12) being communicated with the return pipeline (7); An air inlet pipe (902), arranged on the tank body (901), one end of the air inlet pipe (902) being communicated with the outside, and the other end of the air inlet pipe (902) being communicated with the second air inlet (9012), the air inlet pipe (902) being used to transport the heat around the welding mechanism (5) into the tank body (901); The heat dissipation tank (9) further includes: An annular pipe (13) disposed on the inner wall of the tank body (901), and the annular pipe (13) is communicated with the air inlet pipe (902); An impeller (14) rotatably disposed on the inner wall of the tank body (901), and the impeller (14) is coaxially arranged with the first nozzle (12), and the impeller (14) is rotatably sleeved on the first nozzle (12); A plurality of second nozzles (15) are spaced apart on the annular pipe (13), the second nozzles (15) are communicated with the annular pipe (13), and the second nozzles (15) are used for jetting air to the impeller (14) to drive the impeller (14) to rotate.

2. The pipe making machine without welding marks according to claim 1, characterized in that, The roll forming mechanism (3) includes: A plurality of extrusion rollers (302) are sequentially rotatably disposed on the workbench (1); A grooving roller (301) is rotatably disposed on the feeding end (101), and the grooving roller (301) is used for extruding grooves on both sides of the plate (2). After the plate (2) is bent, the grooves are located at the joint of the circular pipe (6).

3. The pipe-making machine without welding marks according to claim 1, characterized in that, It further includes: A pressure relief pipeline (904) is disposed on the tank body (901), and the pressure relief pipeline (904) has a plurality of pressure relief ports (9041) arranged at intervals, and the plurality of pressure relief ports (9041) are all communicated with the tank body (901); An exhaust valve (903) is disposed at one end of the pressure relief pipeline (904).

4. A pipe-making machine without weld marks according to claim 1, characterized in that, It further includes: A slag removing block (11) is disposed on the workbench (1), and the slag removing block (11) is used for removing the welding slag at the pipe joint.

5. A pipe manufacturing method, applied to a pipe manufacturing machine without weld marks according to any one of claims 1-4, characterized in that, It includes the following steps: S1. The plate (2) enters the roll forming mechanism (3), and the roll forming mechanism (3) bends the plate (2) into a circular pipe (6); S2. The welding mechanism (5) welds the joint of the circular pipe (6); S3. The waste heat recovery box collects the heat dissipated by the circular pipe (6) after welding; S4. The return pipeline (7) conveys the heat collected by the waste heat recovery box (4) to the circular pipe (6) before welding.

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