Manufacturing method of welded square tube

Abstract

The invention relates to a method for manufacturing a welded square tube, which comprises the following steps of: rolling a plate, keeping a butt joint seam at the top end of a round tube, extruding the round tube to form a square tube in an inclined state, enabling the butt joint seam to be positioned on one edge of the top of the square tube, welding the butt joint seam, enabling a welding seam to be positioned on one edge of the square tube, and welding the square tube. Therefore, the technical problem that the strength and attractiveness of the square tube are reduced due to the fact that the welding seam is located in the middle of the side wall of the square tube is solved, the strength and attractiveness of the welded square tube are improved, the technological process of forming grooves in the two side edges of a plate can be omitted, the production process is simplified, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of sheet metal processing, and particularly relates to a method for manufacturing a welded square tube. Background Art

[0002] Square tubes are widely used in the manufacturing and construction fields. Square tubes can be divided into seamless square tubes and welded square tubes according to different production processes. Seamless square tubes need to be rolled with seamless round tubes as the base material. This type of square tube is expensive due to its high material cost and is often used in high-end manufacturing fields. Welded square tubes are made of ordinary plates by curling and welding. Their material cost is low, so the price of the finished square tube is also lower and the user acceptance is higher.

[0003] Patent No. ZL 201010107817.0 discloses a square tube, a frame structure, a method for manufacturing the square tube, and an apparatus for manufacturing the square tube. The square tube is the welded square tube described in the present invention. This prior art method involves first bending a sheet of material four times at obtuse angles, then externally pressing the sheet to convert the obtuse angles into right angles, butting the two edges of the sheet together to form a square tube, and then welding the two butted edges of the sheet to form the welded square tube.

[0004] The welded square tube produced by this manufacturing method has a weld located in the middle of one side wall of the square tube. This requires cutting of both sides of the plate before welding so that a welding groove can be formed when the two sides of the plate are butted together, which increases the difficulty of processing. At the same time, the weld being located in the middle of the side wall also reduces the strength and aesthetics of the welded square tube.

[0005] The invention patent with patent number ZL 202110959623.1 discloses a multi-specification square tube rolling forming system. Although the system rolls the plate into a square tube at one time by rolling, it still cannot overcome the technical problem that the square tube weld is located in the middle of the side wall. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide a method for manufacturing a welded square tube, which solves the technical problem that the weld seam of the square tube is located in the middle of the side wall, resulting in reduced strength and aesthetics of the welded square tube.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is: a method for manufacturing a welded square tube, characterized in that it includes the following specific steps: a. Plate pretreatment: Grind away the garbage on the plate surface; b. Sheet rolling: The sheet that has completed step a is introduced into a multi-pass roller rolling mechanism. The sheet passes through each roller group in sequence and is gradually rolled into a round tube. The two sides of the sheet are turned up and abut against each other at the top of the round tube. c. Round tube roller squaring: The round tube obtained in step b is introduced into the multi-pass square tube extrusion mechanism downstream of the multi-pass roller-type rounding mechanism. The round tube is extruded by the square tube extrusion roller group in each pass to gradually form an inclined square tube. One edge of the square tube is at the top, and the two sides of the plate converge on the edge at the top of the square tube. d. Welding: welding the welding groove of the pipe obtained in step c using welding equipment; e. Weld surface treatment: Surface treatment of the weld of the square tube after step d, including scraping off the weld protrusion, grinding the weld surface, air cooling, flaw detection and water cooling of the weld; f. Shaping: Introduce the square tube completed in step e into the Turkish head for straightening.

[0008] As a preferred solution, after completing step b, step d is directly performed, and then steps c, e, and f are performed in sequence.

[0009] As a preferred solution, the multi-pass roller rolling mechanism includes a plurality of forming roller frames arranged in sequence, and any forming roller frame is rotatably connected to two roller shafts arranged in parallel up and down, and the two roller shafts on the same forming roller frame are respectively fixedly sleeved with a support roller and a pressure roller, and a rolling cavity is formed between the support roller and the pressure roller. Each roller shaft is driven to rotate by a driving mechanism, and the driving mechanism includes a motor and a reducer that are mutually transmission-connected, and the output shaft of the reducer is transmission-connected to each roller shaft through a gear transmission pair and a universal joint.

[0010] As a preferred solution, the multi-pass square tube extrusion mechanism includes a plurality of extrusion roller frames arranged in sequence and an inclined bed supporting each extrusion roller frame. The inclined bed has an inclined table top, and each extrusion roller frame is vertically connected to the table top. Any extrusion roller frame is rotatably connected to two rotating shafts arranged in parallel up and down and parallel to the table top. The rotating shafts are arranged along the inclined direction of the table top. A pressing wheel is respectively sleeved on the two rotating shafts. Both pressing wheels are provided with extrusion grooves. The extrusion groove on the upstream pressing wheel is an arc groove that matches the circular tube, and the extrusion groove on the downstream is a flat-bottomed U-shaped groove. The shape of the extrusion groove on each intermediate pressing wheel gradually transitions from an arc groove to a flat-bottomed U-shaped groove from upstream to downstream. Each rotating shaft is driven to rotate by a driving mechanism. The driving mechanism includes a motor and a reducer that are mutually transmission-connected. The output shaft of the reducer is transmission-connected to each rotating shaft through a gear transmission pair and a universal joint.

[0011] As a preferred solution, a butt joint guide ring is provided in the extrusion groove of the upper pressing wheel. The cross section of the butt joint guide ring is triangular, and the two side edges of the plate are respectively in contact with the two side surfaces of the butt joint guide ring.

[0012] As a preferred solution, the inclined bed includes an inclined base plate, the lower edge of the base plate is hinged to the frame, the upper part of the base plate is connected to the frame through at least one cylinder, the two ends of the cylinder are hinged to the base plate and the frame respectively, and multiple cylinders are arranged along the square tube conveying direction.

[0013] The beneficial effects of the present invention are as follows: the present invention first rolls the plate into a circle and keeps the butt joint located at the top end of the round tube, then extrude the round tube to form a square tube in an inclined state, so that the butt joint is located on an edge at the top end of the square tube, and then welds the butt joint so that the weld is located on an edge of the square tube, thereby avoiding the technical problem of reduced strength and aesthetics of the square tube caused by the weld being located in the middle of the side wall of the square tube, improving the strength and aesthetics of the welded square tube, and omitting the process of opening grooves on both sides of the plate, simplifying the production process, and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings, wherein: Figure 1 Schematic diagram of the arrangement structure of the multi-pass roller-type rolling mechanism of the present invention; Figure 2 This is a schematic diagram of the specific structure of one pass of the multi-pass roller-type rolling mechanism of the present invention; Figure 3 This is a schematic diagram of the specific structure of one pass of the multi-pass square tube extrusion mechanism of the present invention; Figure 4 yes Figure 3 A magnified view of part A in FIG; Figures 1 to 4 In: 1. Forming roller frame; 101. Roller shaft; 102. Support roller; 103. Press roller; 104. Rolling cavity; 2. Motor; 3. Reducer; 4. Gear transmission pair; 5. Universal joint; 6. Extrusion roller frame; 7. Inclined bed; 701. Bottom plate; 702. Cylinder; 8. Table; 9. Rotating shaft; 10. Press roller; 11. Extrusion groove; 12. Butt joint guide ring; 13. Frame. DETAILED DESCRIPTION

[0015] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. Example 1

[0016] The manufacturing method of the welded square tube comprises the following specific steps: a. Plate pretreatment: Grind away the debris on the plate surface. A grinder can be used to grind the plate surface to remove the debris on the plate surface.

[0017] b. Sheet rolling: The sheet that has completed step a is introduced into a multi-pass roller rolling mechanism. The sheet passes through each roller group in sequence and is gradually rolled into a round tube. The two sides of the sheet are turned up and abut against each other at the top of the round tube. c. Roller squaring of round tubes: The round tube obtained in step b is introduced into the multi-pass square tube extrusion mechanism downstream of the multi-pass roller-type rounding mechanism. The round tube is extruded by the square tube extrusion roller group in each pass to gradually form an inclined square tube. One edge of the square tube is located at the top, and the two sides of the plate converge on the edge at the top of the square tube, forming a V-shaped welding groove between the two sides of the plate; d. Welding: Using welding equipment to weld the welding groove of the square tube completed in step c; e. Weld surface treatment: Surface treatment of the weld of the square tube after step d, including scraping off the weld protrusion, grinding the weld surface, air cooling, flaw detection and water cooling of the weld; f. Shaping: Introduce the square tube completed in step e into the Turkish head for straightening.

[0018] like Figure 1 and Figure 2 As shown, the multi-pass roller-type rolling mechanism described in this embodiment includes multiple sequentially arranged forming roller frames 1. Each forming roller frame 1 is rotatably connected to two vertically parallel roller shafts 101. A support roller 102 and a pressure roller 103 are fixedly sleeved onto each of the two roller shafts 101 on the same forming roller frame 1. A rolling cavity 104 is formed between the support rollers 102 and the pressure roller 103. Each roller shaft 101 is driven to rotate by a drive mechanism comprising a motor 2 and a reducer 3 in transmission connection with each other. The output shaft of the reducer 3 is transmission-connected to each roller shaft 101 via a gear pair 4 and a universal joint 5. The rotation of each roller shaft 101 drives the support rollers 102 and the pressure roller 103, squeezing and rolling the sheet material. The drive mechanisms for each pass of the multi-pass roller-type rolling mechanism share a common motor 2 and reducer 3 to maintain a consistent drive speed.

[0019] like Figure 3 and Figure 4As shown, the multi-pass square tube extrusion mechanism in this embodiment includes a plurality of extrusion roller frames 6 arranged in sequence along the pipe conveying direction and an inclined bed 7 supporting each extrusion roller frame 6. The inclined bed 7 has an inclined table 8. Each extrusion roller frame 6 is vertically connected to the table 8. Any extrusion roller frame 6 is rotatably connected to two rotating shafts 9 arranged in parallel up and down and parallel to the table 8. The rotating shaft 9 is arranged along the inclined direction of the table 8. A pressing wheel 10 is respectively sleeved on the two rotating shafts 9. Both pressing wheels 10 are provided with an extrusion groove 11. The extrusion groove 11 on the upstream pressing wheel 10 is an arc groove that matches the round tube, and the extrusion groove 11 of the downstream pressing wheel 10 is a flat-bottomed U-shaped groove. The shape of the extrusion groove 11 on each intermediate pressing wheel 10 gradually transitions from an arc groove to a flat-bottomed U-shaped groove from upstream to downstream. Each rotating shaft 9 is driven to rotate by a driving mechanism. The driving mechanism includes a motor 2 and a reducer 3 that are mutually transmission-connected. The output shaft of the reducer 3 is transmission-connected to each rotating shaft 9 through a gear transmission pair 4 and a universal joint 5. The rotation of each rotating shaft 9 drives each pressing wheel 10 to rotate, thereby squeezing the round tube and gradually transforming the round tube into a square tube.

[0020] In this embodiment, a butt joint guide ring 12 is provided in the extrusion groove 11 of the upper pressing wheel 10. The cross section of the butt joint guide ring 12 is triangular, and the two side edges of the plate are respectively in contact with the two side surfaces of the butt joint guide ring 12.

[0021] In this embodiment, the inclined bed 7 includes an inclined base plate 701. The lower edge of the base plate 701 is hinged to the frame 13. The upper portion of the base plate 701 is connected to the frame 13 via at least one cylinder 702. The ends of the cylinder 702 are respectively hinged to the base plate 701 and the frame 13. Multiple cylinders 702 are arranged along the conveying direction of the square tubes.

[0022] By using this special inclined bed 7, the inclination of the inclined bed 7 can be adjusted according to user needs, thereby adjusting the position of the weld on the welded square tube. The weld can be adjusted to one side or the middle of an edge of the welded square tube, which can meet more user needs.

[0023] In this embodiment, the welding equipment and weld surface treatment equipment used in steps d, e, and f are all conventional equipment, and users can choose them according to their needs. For example, the welding equipment can use a laser welder or an argon arc welder, the weld protrusion scraping device can use a scraper or a milling cutter, the grinding device for weld grinding can be an angle grinder, the weld air-cooling and water-cooling equipment can be a fan and a sprinkler head, and the flaw detection device can be an RT flaw detector. Example 2

[0024] The manufacturing method of the welded square tube comprises the following specific steps: a. Plate pretreatment: Grind away the debris on the plate surface. A grinder can be used to grind the plate surface to remove the debris on the plate surface.

[0025] b. Sheet rolling: The sheet that has completed step a is introduced into a multi-pass roller rolling mechanism. The sheet passes through each roller group in sequence and is gradually rolled into a round tube. The two sides of the sheet are turned up and abut against each other at the top of the round tube. d. Welding: Using welding equipment to weld the welding groove of the pipe completed in step b; c. Round tube roller squaring: The round tube obtained in step d is introduced into the multi-pass square tube extrusion mechanism downstream of the multi-pass roller-type rounding mechanism. The round tube is extruded by the square tube extrusion roller group in each pass to gradually form an inclined square tube. One edge of the square tube is at the top, and both sides of the plate converge on the edge at the top of the square tube. e. Weld surface treatment: Surface treatment of the weld of the square tube after step d, including scraping off the weld protrusion, grinding the weld surface, air cooling, flaw detection and water cooling of the weld; f. Shaping: Introduce the square tube completed in step e into the Turkish head for straightening.

[0026] After completing step b, proceed directly to step d, and then proceed to steps c, e, and f in sequence.

[0027] The multi-pass roller rolling mechanism used in this embodiment is the same as that in Example 1, and the multi-pass square tube extrusion mechanism is also basically the same as that in Example 1, except that in the multi-pass square tube extrusion mechanism in this embodiment, the pressing wheel 10 is not provided with a butt joint guide ring.

[0028] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some embodiments of its application, and are not intended to limit the present invention. It should be noted that a person skilled in the art can make several modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for manufacturing a welded square tube, characterized in that: The specific steps include: a. Plate pretreatment: Grind away the garbage on the plate surface; b. Plate rolling: The plate completed in step a is introduced into a multi-pass roller rolling mechanism, and the plate is gradually rolled into a round tube by passing through each pass of the rolling roller group, and the two sides of the plate are turned up and abutted against each other at the top of the round tube; c. Rolling round tube square: The round tube obtained in step b is introduced into the multi-pass square tube extrusion mechanism downstream of the multi-pass roller-type rounding mechanism. The round tube is extruded by the square tube extrusion roller group of each pass to gradually form an inclined square tube. One edge of the square tube is located at the top, and both sides of the plate converge on an edge at the top of the square tube. d. Welding: welding the welding groove of the pipe completed in step c using welding equipment; e. Weld surface treatment: Surface treatment of the weld of the square tube completed in step d, including scraping off the welding protrusion, grinding the weld surface, air cooling, flaw detection and water cooling of the weld; f. Shaping: Introduce the square tube completed in step e into the Turkish head for straightening.

2. The method for manufacturing a welded square tube according to claim 1, characterized in that: After completing step b, proceed directly to step d, and then proceed to steps c, e, and f in sequence.

3. The method for manufacturing a welded square tube according to claim 1 or 2, characterized in that: The multi-pass roller rolling mechanism includes a plurality of forming roller frames arranged in sequence, and any forming roller frame is rotatably connected to two roller shafts arranged in parallel up and down, and a support roller and a pressure roller are fixedly sleeved on the two roller shafts on the same forming roller frame respectively, and a rolling cavity is formed between the support roller and the pressure roller, and each roller shaft is driven to rotate by a driving mechanism, and the driving mechanism includes a motor and a reducer which are transmission-connected to each other, and the output shaft of the reducer is transmission-connected to each roller shaft through a gear transmission pair and a universal joint.

4. The method for manufacturing a welded square tube according to claim 1, characterized in that: The multi-pass square tube extrusion mechanism includes a plurality of extrusion roller frames arranged in sequence and an inclined bed supporting each extrusion roller frame, the inclined bed having an inclined table top, each extrusion roller frame being vertically connected to the table top, any extrusion roller frame being rotatably connected with two rotating shafts arranged in parallel up and down and parallel to the table top, the rotating shafts being arranged along the inclined direction of the table top, a pressing wheel being respectively sleeved on the two rotating shafts, both pressing wheels being provided with extrusion grooves, the extrusion groove on the upstream pressing wheel being an arc groove matching the round tube, the extrusion groove on the downstream being a flat-bottomed U-shaped groove, the shape of the extrusion groove on each intermediate pressing wheel gradually transitioning from an arc groove to a flat-bottomed U-shaped groove from the upstream to the downstream, each rotating shaft being driven to rotate by a driving mechanism, the driving mechanism comprising a motor and a reducer connected to each other in transmission, the output shaft of the reducer being connected to each rotating shaft in transmission through a gear transmission pair and a universal joint.

5. The method for manufacturing a welded square tube according to claim 4, characterized in that: A butt joint guide ring is arranged in the extrusion groove of the upper pressing wheel, the cross section of the butt joint guide ring is triangular, and the edges on both sides of the plate are respectively attached to the two side surfaces of the butt joint guide ring.

6. The method for manufacturing a welded square tube according to claim 4, characterized in that: The inclined bed includes an inclined bottom plate, the lower edge of the bottom plate is hinged on the frame, the upper part of the bottom plate is connected to the frame through at least one cylinder, the two ends of the cylinder are respectively hinged to the bottom plate and the frame, and multiple cylinders are arranged along the square tube conveying direction.

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