A sleeve-type push tube head for reducing the rolling ear of an automatic pipe mill
The design of the sleeve-type pusher head solves the problem of earing in thin-walled steel pipes, improves yield and rolling efficiency, and reduces the generation of earing and manual turning time.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- LAIGANG GRP YANTAI STEEL PIPE CO LTD
- Filing Date
- 2025-07-16
- Publication Date
- 2026-06-02
AI Technical Summary
When automatic tube rolling mills roll thin-walled steel pipes, especially at the tail end of the thin-walled steel pipes, earing is easily generated, which leads to a decrease in yield and low rolling efficiency.
The sleeve-type pusher head features a design where the inner cavity of the barrel gradually decreases in size. Combined with a cylinder connecting rod and a rotating structure, this design ensures that the tail end of the steel pipe does not expand during the pushing process. Furthermore, the guide platform and retractable pipe stop prevent jamming, allowing the steel pipe to be smoothly flipped and removed.
It effectively reduces the formation of rolled ears, improves yield and rolling efficiency, reduces manual turning time, and extends the production cycle.
Smart Images
Figure CN224309294U_ABST
Abstract
Description
Technical Field
[0001] This solution relates to the field of steel pipe processing, specifically to a sleeve-type pusher head that reduces the rolling of ears in automatic pipe rolling mills. Background Technology
[0002] The process flow of the automatic tube rolling mill:
[0003] The heated solid billet is pierced by a piercing mill to form a hollow tube, which is then fed into an automatic tube rolling mill. The automatic tube rolling mill reduces the diameter and wall thickness of the tube to form a rough tube, which is then fed into a sizing mill. The sizing mill evens out the wall thickness of the rough tube to improve its accuracy, resulting in a sizing rough tube. This is then fed into a sizing mill, which regularizes the outer diameter of the sizing rough tube to form a high-temperature finished tube. Subsequently, it undergoes cooling, straightening, and finishing to obtain the final finished steel pipe. Note: For the sake of simplicity, the pierced tube (circular cross-section), rolled rough tube (elliptical cross-section), sizing rough tube (circular cross-section), and high-temperature finished tube (circular cross-section) mentioned above are all referred to as steel pipes when applicable in the following description.
[0004] An automatic tube rolling mill consists of three parts: a main unit, a front-end unit, and a back-end unit. The main unit is equipped with a set of work rolls, each with a circular groove machined into it. The tube blank fed from the piercing mill is rolled in an annular die formed by the circular groove and a mandrel. Each set of work rolls comprises at least two roll bodies, which together form a complete circular die. Figure 2 As shown, the gap at the junction of the work rolls is called roll gap 211. During the rolling process, the steel pipe 25 is squeezed into roll gap 211, which produces what is known in the industry as the rolled ear.
[0005] Automatic tube rolling mill operation process: The slots of two active rotating rolls close to form a circular die. The push rod 23 pushes the mandrel 24 and is located inside the die. The pusher head 26 pushes the steel pipe 25 from the tail end and feeds it into the die from the front table 29 for one pass of rolling. After rolling: the steel pipe 25 enters the back table, the upper roll 21 is raised, the mandrel 24 falls off and leaves the rolling line. At the same time, the lower roll of the return roll 22 is raised and closes with the upper roll of the return roll 22 to form a return die. The rotation direction of the return roll 22 is opposite to the rolling direction, so it can clamp the steel pipe 25 and return the steel pipe 25 to the front table 29. After the steel pipe 25 is returned: the upper roll 21 is pressed down and closes with the lower roll, the mandrel 24 returns to the rolling line in front of the die, and the lower return roll 22 descends to avoid the steel pipe 25, preparing for the next pass of rolling.
[0006] Since its inception, the automatic tube rolling mill has had the problem of rolled ears, especially during the rolling process of thin-walled tubes, where rolled ears are particularly prone to occur at the tail of the steel tube.
[0007] The commonly used conical pusher head 26 is driven by a pneumatic cylinder 28, pushing the rough tube forward from the tail of the steel pipe 25. The reason for using a conical pusher head 26 is that the conical part 31 needs to be inserted into the inner cavity of the rough tube head to achieve close contact with the steel pipe 25, so that the conical pusher head 26 can rotate under the drive of the rotating mechanism 27, causing the steel pipe 25 to rotate 90°. Figure 1 The schematic conical pusher head 26 includes a conical part 31 and a cylindrical part 32. The conical part 31 is inserted into the inner cavity of the tail end of the steel pipe 25 and is in close contact with the steel pipe 25 so that it can drive the steel pipe 25 to rotate 90° later. The diameter of the cylindrical step at the joint end of the cylinder 32 and the conical part 31 is greater than or equal to the diameter of the steel pipe 25, which plays the role of pushing the tail end of the steel pipe 25.
[0008] When the conical pusher head 26 pushes the tail end of the steel pipe 25 into the die, the steel pipe 25 is in a high temperature state and the wall thickness is relatively thin. The radial dimension of the tail end of the steel pipe 25 expands. When it enters the die for rolling, the expanded tail end enters the roll gap 211, so the tail end will be rolled into an ear until it breaks.
[0009] As the number of rolling passes increases and the wall thickness of the steel pipe 25 decreases, the pushing force of the pusher head 26 causes the tail end of the steel pipe 25 to expand radially more severely, resulting in a larger rolled ear after the roll pass is rolled.
[0010] In the rolling process of thin-walled steel pipe 25, three rolling passes are generally required. After the first pass, the first ear problem occurs:
[0011] The first pass feed orifice type: The head of the tapered pusher head 26 inserts into the inner cavity of the rough tube. Because the rough tube wall is thin and its bending resistance is weak at high temperatures, the thrust of the tapered pusher head 26 easily causes the tail of the rough tube to deform and expand. Figure 2 As shown, the diameter of the tail-end enlargement 251 is larger than the size of the roll groove bottom 212, so the tail-end enlargement 251 corresponding to the roll gap 211 will enter the roll gap 211, and the rolled portion of the roll gap 211 is in the shape of a first ear, as shown. Figure 3 The shown is a 252mm ferrule;
[0012] After the second rolling pass, the first rolled ear will break, resulting in the second rolled ear problem:
[0013] During the second rolling pass, the steel pipe 25 is rotated 90° so that the steel pipe 25 located at the roll gap 211 position in the first pass is transferred to the bottom of the groove 212 position. Therefore, the first ear will be rolled exactly corresponding to the bottom of the groove 212. The first ear is pressed down and is in a stacked rolling state. After the steel pipe 25 ear is stacked, the ear position is generally in a broken state. At the same time, in the second rolling pass, the conical pusher head 26 once again expands the tail of the steel pipe 25. The expanded tail portion 251 of the rough pipe corresponding to the roll gap 211 re-enters the roll gap 211, and the first ear appears again. However, the position of the first ear this time is 90° different from the first ear produced in the previous pass.
[0014] After the third rolling pass, the second rolled ear was broken, resulting in a new third rolled ear problem:
[0015] In the third rolling pass, the steel pipe 25 is flipped 90° again. At this time, the second ear is rolled by the bottom of the groove 212 and broken. At the same time, the conical pusher head 26 causes the tail end of the steel pipe 25 to expand. Thus, the tail end of the steel pipe 25 is pushed by the conical pusher head 26 three times in a row, causing the tail end to expand. The expanded area spreads inward along the length of the pipe body. The roll gap 211 rolls out the third ear again. As a result, the tail end of the steel pipe 25 breaks repeatedly, and the broken tail ends become longer and longer.
[0016] After three rolling passes, the steel pipe is removed from the rolling line and enters the sizing mill process. The sizing mill pass is designed to fit the diameter of the steel pipe. The rolled ears and broken parts at the tail of the steel pipe are pressed down, forming a broken tail shape. The length is generally around 300mm (or more), which must be cut off, thus seriously affecting the yield.
[0017] Furthermore, the rolling of the end ears of thin-walled steel pipes further increases the difficulty and time required for turning the pipes. Turning the rough pipes is difficult or impossible, requiring manual turning with pipe wrenches to rotate them 90°. Each rotation adds at least 3-5 seconds to the interval time, and two rotations (requiring two 90° rotations in three rolling passes) take 6-10 seconds. This increases the interval time, delays rolling, lengthens the rolling cycle, and severely impacts rolling efficiency and output.
[0018] The industry has done a lot of work in researching and improving the conical pusher head to reduce the formation of earing, but with little success. No research has been reported in other areas, so the earing problem persists. Currently, the yield rate of thin-walled steel pipes in the industry is around 88%, while that of medium-thick-walled steel pipes is around 92%. The 4% difference is mainly due to the fact that the earing problem has not been effectively overcome.
[0019] Therefore, it is urgent to study and solve the relevant problems of ear clamping. Utility Model Content
[0020] The technical problem this invention aims to solve is how to reduce the occurrence of earing during the rolling process of steel pipes, especially during the rolling of thin-walled pipes.
[0021] The specific technical solution of this utility model to solve the above-mentioned technical problems is as follows:
[0022] A sleeve-type pusher head for reducing the ear crushing of automatic pipe rolling mills has an overall sleeve-shaped barrel body. The inner diameter D1 of the open end of the barrel body is larger than the inner diameter D2 of the bottom end of the barrel body. The inner wall of the barrel body smoothly transitions from the open end to the bottom end of the barrel body, and D1 > outer diameter of the rough pipe end D3 > D2, where D1 is larger than D3 (generally 10-20mm) and D3 is larger than D2 (generally 2-5mm) to facilitate the sleeve-type pusher head to clamp the tail of the steel pipe to be processed.
[0023] A cylinder connecting rod is fixedly connected to the outside of the bottom end of the sleeve-type push tube head.
[0024] Compared with the existing technology, this solution has the following advantages: After the tail end of the steel pipe enters the inner cavity of the sleeve-type pusher head, because the bottom diameter of the inner cavity is smaller than the outer diameter of the end of the steel pipe, when the steel pipe is pushed into the hole, the tail end of the steel pipe is restricted and contracted by the barrel wall of the sleeve-type pusher head, and cannot expand. This avoids the situation where the pipe head expands during the pushing process, which could lead to the problem of ear rolling in subsequent processes.
[0025] Furthermore, the cylinder connecting rod or the barrel body is provided with a rotating structure. Based on this rotating structure, the sleeve-type pusher head can be driven to rotate 90° by an external drive mechanism, such as a gear, sprocket, or crank arm connecting rod, to adjust the position of the steel pipe for the next processing step and further reduce the occurrence of earing.
[0026] Furthermore, it also includes a guide platform for guiding the steel pipe into the barrel. Since the steel pipe is placed between rollers or inclined plates on the front platform, and the sleeve-type pusher head is also set between two rollers or inclined plates, when the tail end face of the steel pipe is close to the sleeve-type pusher head, its lowest point is often lower than the lowest point of the sleeve-type pusher head, making it impossible to smoothly enter the sleeve-type pusher head. Therefore, a guide platform is further set on the sleeve-type pusher head to guide the tail end of the steel pipe smoothly into the sleeve-type pusher head.
[0027] Furthermore, the barrel is rotatably mounted on the guide platform, meaning that the guide platform can move back and forth along the axial direction synchronously with the sleeve-type pusher head, but does not rotate with the circumferential rotation of the sleeve-type pusher head, ensuring that the guide platform can always guide the steel pipe into the sleeve-type pusher head, and does not hinder the sleeve-type pusher head from carrying the steel pipe to rotate 90°.
[0028] Furthermore, it also includes a retractable pipe stopper, which is retractably installed inside the barrel. This solution eliminates the need for an additional pipe stopper. When the sleeve-type pipe pusher head is needed to clamp the steel pipe, the retractable pipe stopper is retracted inside the sleeve-type pipe pusher head. When the sleeve-type pipe pusher head is not needed to clamp the steel pipe, the pipe stopper extends out of the sleeve-type pipe pusher head to prevent the tail end of the steel pipe from entering the inner cavity of the sleeve-type pipe pusher head.
[0029] Furthermore, the retractable tube stopper includes a tube stop plate, a connecting rod, and a limiting plate. The tube stop plate and the limiting plate are fixedly connected together via the connecting rod. The bottom of the barrel has a through hole for the connecting rod to pass through. A return spring is provided between the limiting plate and the bottom plate of the barrel. It also includes a stop wall, which abuts against the limiting plate when the sleeve-type pusher head retracts to the zero position to restrict the tube stopper from retracting along with the sleeve-type pusher head.
[0030] The above describes the structure of a telescopic pipe stopper. In conjunction with a stop wall positioned between the sleeve-type pusher head and the cylinder, when the sleeve-type pusher head is no longer needed to receive the steel pipe, the cylinder drives the sleeve-type pusher head to move backward, carrying the telescopic pipe stopper. When the limit plate of the telescopic pipe stopper abuts against the stop wall, the telescopic pipe stopper can no longer move backward. The cylinder continues to pull the sleeve-type pusher head backward. At this time, the spring at the bottom of the sleeve-type pusher head is compressed, and the pipe stopper plate moves outward relative to the sleeve-type pusher head until it reaches outside the opening end of the sleeve-type pusher head. Any incoming steel pipe will then be blocked outside the sleeve-type pusher head's barrel by the pipe stopper plate, preventing the pipe head from getting stuck inside the sleeve-type pusher head and being unable to be pulled out, thus affecting the steel pipe's removal from the rolling mill. Attached Figure Description
[0031] Figure 1 This is a schematic diagram analyzing the causes of ear-crushing.
[0032] Figure 2 yes Figure 1 Schematic diagram of the cross-sectional structure along the middle AA direction;
[0033] Figure 3 This is a diagram of a clamped ear;
[0034] Figure 4 This is a schematic diagram of the first embodiment of the sleeve-type pusher head of this utility model;
[0035] Figure 5 This is a cross-sectional schematic diagram of the first embodiment of the sleeve-type push tube head of this utility model;
[0036] Figure 6 This is a schematic diagram of the second embodiment of the sleeve-type pusher head of this utility model;
[0037] Figure 7 This is a schematic diagram of the first state of the third embodiment of the sleeve-type pusher head of this utility model;
[0038] Figure 8 This is a schematic diagram of the second state of the third embodiment of the sleeve-type pusher head of this utility model.
[0039] The following is a list of component names represented by the reference numerals in the attached diagram:
[0040] 20. Roller conveyor; 21. Upper roll; 22. Upper return roll; 23. Top rod; 24. Top head; 25. Steel pipe; 26. Pusher head; 27. Rotating mechanism; 28. Pneumatic cylinder; 29. Front stage; 211. Roll gap; 212. Gutter bottom; 251. Expansion section; 31. Conical section; 32. Cylinder; 411. Barrel body; 412. Baffle plate; 413. Connecting rod; 414. Stop wall; 415. Limiting plate; 416. Return spring; 417. Guide table; 418. Cylinder connecting rod; 419. Gear. Detailed Implementation
[0041] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.
[0042] Example 1:
[0043] like Figure 4 , Figure 5 As shown, a sleeve-type pusher head 26 for reducing the earing of an automatic pipe rolling mill has an overall sleeve-shaped barrel 411. The inner diameter D1 of the open end of the barrel 411 is larger than the inner diameter D2 of the bottom end. The inner wall of the barrel 411 smoothly transitions from the open end to the bottom end, and D1 > outer diameter of the rough pipe end D3 > D2, where D1 is greater than D3 (10-20mm or larger) and D3 is greater than D2 (2-5mm or larger) to facilitate the sleeve-type pusher head 26 to clamp the rough pipe to be processed. In this embodiment, when the sleeve-type pusher head 26 is in use, the end of the steel pipe 25 will be inserted into the sleeve-type barrel 411. Since the inner diameter D2 of the barrel 411 is smaller than the outer diameter D3 of the rough pipe (2-5mm, or larger), the steel pipe 25 will be clamped in the sleeve-type pusher head 26. As needed, the sleeve-type pusher head 26 can rotate the steel pipe 25 by 90 degrees. When pushing the steel pipe 25 into the rolling mill pass, the barrel wall of the sleeve-type pusher head 26 will restrict the expansion of the end of the steel pipe 25, thereby avoiding the problem of earing during the rolling process caused by the expansion of the end. And the steel pipe 25 is pulled out from the sleeve-type pusher head 26 by the pulling force during the rolling of the rolling mill.
[0044] There are many techniques to achieve a 90° rotation of the sleeve-type pusher head 26. For example, in this case, a square cylinder connecting rod 418 is fixed to the bottom of the barrel 411. A sprocket, gear 419, or other drive structure can be further fixed to this cylinder connecting rod 418, and the 90° rotation can be achieved by an external actuator. Additionally, this example includes... Figure 1 The barrel 411 also has a ring of teeth forming a gear 419 on the outer periphery of its bottom. It can also be directly meshed with the teeth on the barrel 411 by an external actuator to achieve rotation of the sleeve-type push tube head 26.
[0045] In the final process, when it is not necessary to push the steel pipe 25 into the rolling mill pass again, an independently set pipe stopper should be used to intercept the steel pipe 25 in front of the sleeve-type pipe pusher head 26 to prevent the tail end of the steel pipe 25 from getting stuck in the sleeve-type pipe pusher head 26 and being unable to be pulled out, thus preventing it from being successfully sent to the next process.
[0046] Example 2:
[0047] like Figure 6 As shown, this example adds a guide platform 417 based on embodiment 1. The sleeve-type pusher head 26 is provided with a groove, and the guide platform 417 is provided with a rib. The groove and the rib are adapted to each other, thereby realizing that the sleeve-type pusher head 26 can be rotatably set on the guide platform 417. The guide platform 417 can move back and forth along the axial direction synchronously with the sleeve-type pusher head 26, but does not rotate with the circumferential rotation of the sleeve-type pusher head 26, ensuring that the guide platform 417 can always guide the steel pipe 25 into the sleeve-type pusher head 26, and does not hinder the sleeve-type pusher head 26 from carrying the raw pipe to rotate 90°. The purpose of setting up the guide platform 417 is as follows: the raw pipe is conveyed based on the roller conveyor 20, and the sleeve-type pusher head 26 is set between the two roller conveyors 20. When the tail end of the steel pipe 25 is close to the sleeve-type pusher head 26, its lowest point is often lower than the lowest point of the sleeve-type pusher head 26, which makes it impossible to smoothly enter the sleeve-type pusher head 26. Therefore, the guide platform 417 is further set on the sleeve-type pusher head 26 to guide the end of the raw pipe into the sleeve-type pusher head 26.
[0048] Of course, in Embodiment 1, the guide platform 417 is not provided. Instead, the steel pipe 25 can be lifted to a certain height by an additional steel pipe 25 lifting device so that the steel pipe 25 can smoothly enter the sleeve-type pusher head 26.
[0049] Example 3:
[0050] like Figure 7As shown, this example adds a retractable pipe stopper to the existing embodiment 1. The pipe stopper is retractably installed inside the barrel 411 and includes a pipe stopper plate 412, a connecting rod 413, and a limiting plate 415. The pipe stopper plate 412 and the limiting plate 415 are fixedly connected together via the connecting rod 413. The bottom of the barrel 411 has a through hole for the connecting rod 413 to pass through. A return spring 416 is provided between the limiting plate 415 and the bottom plate of the barrel 411. A stop wall 414 is also included, which abuts against the limiting plate 415 when the sleeve-type pusher head 26 retracts to the zero position to restrict the pipe stopper from retracting along with the sleeve-type pusher head 26.
[0051] Guided by the guide plate 417, the tail end of the steel pipe 25 enters the inner cavity of the sleeve-type pusher head 26 and is squeezed tightly.
[0052] If a 90° rotation is not required, the sleeve-type pusher head 26, under the push of the external cylinder, feeds the steel pipe 25 into the die for rolling, and the rolling tension disengages the tail end of the steel pipe 25 from the inner cavity of the sleeve.
[0053] If a 90° rotation is required, an external actuator drives the sleeve-type pusher head 26 to rotate the steel pipe 25 by 90°, and then feeds the steel pipe 25 into the die for rolling. There are many types of structures that drive the sleeve-type pusher head 26 to rotate 90°, such as gears, sprockets, and crank arm connecting rods.
[0054] After the final rolling pass is completed, the steel pipe 25 no longer needs to be pushed into the die again, so there is no need to prevent the end from expanding. Before the steel pipe 25 is returned to the front end 29, the cylinder pulls the sleeve-type push head 26 back to the origin zero position. When the stop wall 414 abuts against the limit plate 415 of the telescopic tube stopper, the cylinder further pulls the sleeve-type push head 26 back, and the return spring 416 will be compressed. Under the drive of the cylinder connecting rod, the sleeve-type push head 26 continues to retreat a certain distance. The corresponding tube stopper plate 412 of the telescopic tube stopper moves to the entrance of the sleeve-type push head 26. The diameter of the tube stopper plate 412 is larger than the inner diameter of the steel pipe 25, so it can block the returned steel pipe 25 and prevent the tail end of the steel pipe 25 from getting stuck in the inner cavity of the sleeve-type push head 26. The material feeding device can then push the steel pipe 25 away from the rolling line.
[0055] In this example, the tail end of the steel pipe 25 enters the inner cavity of the sleeve-type pusher head 26. When the steel pipe 25 is pushed forcefully into the feed hole, the tail end of the steel pipe 25 cannot expand, thus eliminating the ear roll.
[0056] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.
Claims
1. A sleeve-type pusher head for reducing the camber of an automatic tube rolling mill, characterized in that, The device includes a sleeve-shaped barrel, which has a bottom end and an open end. The inner diameter D1 of the open end of the barrel is greater than the inner diameter D2 of the bottom end. The inner wall of the barrel smoothly transitions from the open end to the bottom end, and D1 > outer diameter of the rough tube end D3 > D2, so that the sleeve-type pusher head can clamp the rough tube to be processed. A cylinder connecting rod is fixedly connected to the bottom end of the sleeve-type push tube head.
2. The sleeve-type pusher head for reducing the rolling ears of an automatic tube rolling mill according to claim 1, characterized in that, The cylinder connecting rod or barrel body is provided with a rotating structure.
3. The sleeve-type pusher head for reducing the rolling ears of an automatic tube rolling mill according to claim 1 or 2, characterized in that, It also includes a guide platform for guiding the steel pipe into the barrel.
4. The sleeve-type pusher head for reducing the rolling ears of an automatic tube rolling mill according to claim 3, characterized in that, The barrel is rotatably mounted on the guide platform.
5. The sleeve-type pusher head for reducing the rolling ears of an automatic tube rolling mill according to claim 4, characterized in that, It also includes a retractable pipe stopper, which is retractably disposed within the barrel.
6. The sleeve-type pusher head for reducing the rolling ears of an automatic tube rolling mill according to claim 5, characterized in that, The retractable tube stopper includes a tube stop plate, a connecting rod, and a limiting plate. The tube stop plate and the limiting plate are fixedly connected together via the connecting rod. The bottom of the barrel is provided with a through hole for the connecting rod to pass through. A return spring is provided between the limiting plate and the bottom plate of the barrel. It also includes a stop wall, which is used to abut against the limiting plate when the sleeve-type push tube head returns to the zero position to limit the tube stopper from retracting with the sleeve-type push tube head.