Stepped core rod and continuous pipe rolling mill
By using step core rods in continuous pipe rolling mills, the problem of thickening of the wall thickness at the head and tail ends in steel pipe rolling is solved, and uniform changes in wall thickness and improvement of production efficiency are achieved.
Patent Information
- Application Number
- CN202421536577.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-01
- Publication Date
- 2025-05-27
- Estimated Expiration
- 2034-07-01
AI Technical Summary
The existing continuous pipe rolling mills use mandrels of uniform thickness for steel pipe rolling, which can easily lead to thickening of the wall thickness of the steel pipe head and tail ends, reducing production efficiency.
A step core rod is adopted, including a head end thickness reduction part, a first transition part, a molding part, a second transition part and a tail end thickness reduction part. Through the design of these components, the wall thickness of the steel pipe head and tail ends is controlled to ensure that the central dimension of the steel pipe meets the molding standards.
The problem of thickening of the head and tail wall of the steel pipe is effectively controlled, reducing the cutting length of the head and tail ends, and improving the production efficiency of good products for steel pipe rolling.
Smart Images
Figure CN222902154U_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the technical field of steel pipe rolling, and more specifically, relates to a stepped mandrel and a continuous pipe rolling mill. Background Art
[0002] The continuous tube mill belongs to the longitudinal rolling process. During the production process, the tube blank used for the steel pipe is pierced into a hollow rough tube, and then the oxide scale on the inner wall is removed. The rough tube is sent to the front desk of the continuous rolling mill through the rough tube transverse movement device. The mandrel limiting mechanism inserts the cooled and lubricated mandrel into the rough tube. Through the joint action of the rough tube roller and the limiting mechanism, the rough tube and the mandrel enter the continuous tube mill for rolling at the same time.
[0003] At present, existing continuous tube rolling mills often use mandrels with uniform thickness to roll steel tubes.
[0004] The inventors have discovered that the existing continuous tube rolling mill uses a mandrel with uniform thickness to roll steel tubes, which easily leads to thickening of the wall thickness at the head and tail ends of the steel tube. The wall thickness at the head and tail ends of the steel tube exceeds the process requirements, so the two ends of the steel tube need to be cut off, reducing the production efficiency of good products of steel tube rolling. Utility Model Content
[0005] The purpose of the present application is to provide a stepped mandrel to solve the technical problem in the prior art that the existing continuous tube mill uses a mandrel with uniform thickness to roll steel tubes, which easily leads to thickening of the wall thickness at the head and tail ends of the steel tube and reduces the production efficiency.
[0006] In order to achieve the above-mentioned purpose, the technical solution adopted in the present application is: to provide a stepped mandrel, comprising:
[0007] The mandrel body is used to be inserted into the steel pipe; the mandrel body comprises a head end reduced thickness portion, a first transition portion, a forming portion, a second transition portion and a tail end reduced thickness portion which are connected in sequence;
[0008] A mounting member, used for mounting on the continuous tube mill, and detachably connected to the tail end reduced thickness portion;
[0009] Among them, during the rolling process of the steel pipe, the head end thickening portion and the tail end thickening portion are respectively used to expand the inner walls of the head and tail ends of the steel pipe to reduce the wall thickness of the steel pipe; the forming portion is used to abut against the inner wall of the steel pipe so that the size of the middle part of the steel pipe meets the forming standard.
[0010] Preferably, the outer diameters of the head end reduced thickness portion and the tail end reduced thickness portion are both larger than the outer diameter of the forming portion; and along the axial direction of the core rod body, the lengths of the head end reduced thickness portion and the tail end reduced thickness portion are both smaller than the length of the forming portion.
[0011] Preferably, the outer diameter of the first transition portion gradually decreases from the head end thickening portion toward the forming portion, and the outer diameter of the second transition portion gradually decreases from the tail end thickening portion toward the forming portion.
[0012] Preferably, the head end reduced thickness portion has an oblique frustum, and the outer diameter of the oblique frustum gradually decreases in a direction away from the forming portion;
[0013] Wherein, during the process of inserting the core rod body into the steel pipe, the inclined frustum is suitable for first abutting against the steel pipe.
[0014] Preferably, the tail end reduced thickness portion is provided with a boss, and the boss protrudes outward along the axial direction of the mandrel body; the mounting component comprises:
[0015] A mounting seat, used for mounting on the continuous tube mill, and coaxially arranged with the mandrel body;
[0016] A guide column, one end of which is fixedly connected to the boss, and the other end of which extends outwardly along the axial direction of the mandrel body and abuts against the mounting seat; the outer diameter of the guide column is larger than the outer diameter of the boss; and
[0017] A clamping member is hinged on the mounting seat, and the axis direction of the hinge shaft of the clamping member is perpendicular to the axis direction of the mandrel body;
[0018] Wherein, when the clamping member swings toward the core rod body, the clamping member is adapted to be clamped with the guide column to prevent the mounting seat and the guide column from moving in opposite directions.
[0019] Preferably, the clamping member has a groove, and when the clamping member is clamped with the guide post, the guide post is adapted to be embedded in the groove.
[0020] Preferably, the end of the clamping piece facing the mandrel body has an inclined surface, and the inclined surface extends downwardly in a direction away from the mandrel body; the end of the guide column facing away from the mandrel body has a conical surface, and the conical surface extends downwardly in a direction away from the mandrel body;
[0021] Wherein, when the mounting seat moves toward the guide column, the inclined surface is suitable for abutting against the conical surface.
[0022] Preferably, the mounting seat has a positioning groove on a side facing the core rod body; when the mounting seat moves toward the guide column, an end of the guide column facing away from the core rod body is suitable for being embedded in the positioning groove.
[0023] Preferably, an operating handle is provided on the upper side of the clamping member.
[0024] In the embodiment of the present application, when the steel pipe is fed into the continuous tube rolling mill, since the mandrel body is in a backward state relative to the steel pipe, the movement speed of the steel pipe is faster than the movement speed of the mandrel body. After being rolled by the continuous tube rolling mill, the wall thickness of the head end of the steel pipe is correspondingly thinned while the outer diameter of the steel pipe remains unchanged; when the thickened portion at the tail end is close to the tail end of the steel pipe, after being rolled by the continuous tube rolling mill, the wall thickness of the tail end of the steel pipe is correspondingly thinned while the outer diameter of the steel pipe remains unchanged.
[0025] After the rolling process is completed, the mandrel body quickly retreats and exits from the inside of the steel pipe, and finally a steel pipe with thinner wall thickness at both ends than the standard wall thickness is rolled out. The wall thickness thickening at the head and tail of the steel pipe is effectively alleviated and the wall thickness changes evenly, and the cutting length at the head and tail of the steel pipe is effectively shortened.
[0026] Compared with the prior art, the stepped mandrel provided in the embodiment of the present application can effectively control the problem of thickening of the wall thickness of the head and tail of the steel pipe when rolling the steel pipe, reduce the cutting length of the head and tail ends, and improve the production efficiency of good products in steel pipe rolling.
[0027] The technical solution adopted in the present application also provides a continuous tube rolling mill, comprising the stepped mandrel proposed in any of the aforementioned items.
[0028] The beneficial effects of the continuous tube mill provided in this embodiment are the same as those of the aforementioned stepped mandrel, and will not be described in detail here. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0030] Figure 1 The main structure diagram of the step mandrel provided in the embodiment of the present application is shown in FIG. Figure 1 ;
[0031] Figure 2 The main structure diagram of the step mandrel provided in the embodiment of the present application is shown in FIG. Figure 2 ;
[0032] Figure 3 A schematic diagram of the cross-sectional structure of a stepped mandrel provided in an embodiment of the present application;
[0033] Figure 4 for Figure 3 A schematic diagram of the cross-sectional structure of the mounting seat and the clamping member;
[0034] Among them, the reference numerals in the figure are:
[0035] 1. Mandrel body; 2. Reduced thickness portion at the head end; 21. Oblique frustum; 3. First transition portion; 4. Forming portion; 5. Second transition portion; 6. Reduced thickness portion at the tail end; 61. Boss; 7. Mounting member; 71. Mounting seat; 711. Positioning groove; 72. Guide column; 721. Conical surface; 73. Clip; 731. Groove; 732. Inclined surface; 733. Operating handle. DETAILED DESCRIPTION
[0036] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.
[0037] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.
[0038] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.
[0039] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.
[0040] Please also read Figures 1 to 4 Now, the step mandrel provided by the present application is described. The step mandrel comprises a mandrel body 1 and a mounting member 7.
[0041] The mandrel body 1 is used for being inserted into the interior of the steel pipe; the mandrel body 1 comprises a head end reduced thickness portion 2, a first transition portion 3, a forming portion 4, a second transition portion 5 and a tail end reduced thickness portion 6 which are connected in sequence.
[0042] The mounting member 7 is used for mounting on the continuous tube rolling mill, and is detachably connected to the tail end reduced thickness portion 6 .
[0043] Among them, during the steel pipe rolling process, the head end thickening portion 2 and the tail end thickening portion 6 are respectively used to expand the inner walls of the head and tail ends of the steel pipe to reduce the wall thickness of the steel pipe; the forming portion 4 is used to abut against the inner wall of the steel pipe so that the middle size of the steel pipe meets the forming standard.
[0044] The utility model can be used for all specifications of the expansion and reduction machine with a diameter reduction amount greater than 40 mm, and 5 to 7 stepped core rods can be used cyclically.
[0045] During the production process, the tube blank used for the steel pipe is perforated into a hollow rough tube, and then the turning hook turns the steel pipe to the nitrogen and borax spraying process for borax spraying to remove the oxide scale on the inner wall of the steel pipe. After passing through the steel pipe transverse movement device, the steel pipe is sent to the front desk of the continuous rolling mill. The limiting mechanism inserts the cooled and lubricated stepped mandrel into the steel pipe. Through the joint action of the steel pipe roller and the limiting mechanism, the steel pipe and the stepped mandrel enter the continuous rolling mill at the same time to start rolling.
[0046] After rolling is completed, the stepped mandrel enters the cooling station through the conveyor roller for water cooling. The cooling station can adjust the water volume according to the different temperatures of different areas of the stepped mandrel to ensure uniform cooling of the mandrel. The cooled mandrel passes through the cooling station transfer device and enters the stepped mandrel lubrication conveyor roller. The lubricated stepped mandrel is sent to the mandrel preparation position on the mandrel limiting mechanism through the mandrel transfer machine, waiting for the next steel pipe to be rolled, and repeating the above actions.
[0047] It should be noted that in the current continuous rolling production line, the continuous tube mill belongs to longitudinal rolling. During the rolling process, the head and tail of the steel pipe are obviously thickened, and the wall thickness of the head and tail exceeds the process requirements, resulting in an increase in the length of the head and tail of the steel pipe. The current common treatment method is to set a hydraulic small warehouse on the continuous tube mill with a head and tail sharpening function. That is, when the continuous tube mill bites and throws steel, the hydraulic small warehouse is used to press down the roller gap of the continuous tube mill, and at the same time, the roller speed of the continuous tube mill is adjusted to reduce the trend of thickening of the head and tail. This technology is difficult to adjust during use. The sharpening function controls the current rolled tube according to the length of the previous rough tube. The fluctuation of the rough tube length will affect the sharpening effect. At the same time, there will be a sudden change in wall thickness when the head and tail of the steel pipe are sharpened. After the subsequent tensioning and reducing machine, the sudden change in wall thickness will be aggravated, affecting the quality of the wall thickness of the head and tail of the steel pipe, resulting in an increase in the length of the head and tail.
[0048] In the embodiment of the present application, when the steel pipe is fed into the continuous rolling mill, since the mandrel body 1 is in a backward state relative to the steel pipe, the movement speed of the steel pipe is faster than the movement speed of the mandrel body 1. After being rolled by the continuous rolling mill, the wall thickness of the head end of the steel pipe is correspondingly thinned while the outer diameter of the steel pipe remains unchanged; when the tail end thickening portion 6 is close to the tail end of the steel pipe, after being rolled by the continuous rolling mill, the wall thickness of the tail end of the steel pipe is correspondingly thinned while the outer diameter of the steel pipe remains unchanged.
[0049] After the rolling process is completed, the mandrel body 1 quickly retreats and exits from the inside of the steel pipe, and finally a steel pipe with thinner wall thickness at both ends than the standard wall thickness is rolled out. The wall thickness increase at the head and tail of the steel pipe is effectively alleviated and the wall thickness changes evenly, and the cut length at the head and tail of the steel pipe is effectively shortened.
[0050] Compared with the prior art, the stepped mandrel provided in the embodiment of the present application can effectively control the problem of thickening of the wall thickness of the head and tail of the steel pipe when rolling the steel pipe, reduce the cutting length of the head and tail ends, and improve the production efficiency of good products in steel pipe rolling.
[0051] In some embodiments, please refer to Figures 1 to 4 As a specific embodiment of the stepped mandrel provided in the present application, the outer diameters of the head end reduced thickness portion 2 and the tail end reduced thickness portion 6 are both larger than the outer diameter of the forming portion 4; and, along the axial direction of the mandrel body 1, the lengths of the head end reduced thickness portion 2 and the tail end reduced thickness portion 6 are both smaller than the length of the forming portion 4.
[0052] The forming portion 4 is a core rod size designed according to normal process, the outer diameters of the head end reduced thickness portion 2 and the tail end reduced thickness portion 6 are increased, and the variable diameter areas are set between each section according to the steel pipe models of different specifications.
[0053] Among them, the outer diameter of the head end reduced thickness portion 2 is 0.3mm to 0.8mm larger than the outer diameter of the forming portion 4; the length of the head end reduced thickness portion 2 is 1.2m to 2.2m; the outer diameter of the tail end reduced thickness portion 6 is 0.5mm to 1.2mm larger than the outer diameter of the forming portion 4; the length of the tail end reduced thickness portion 6 is 1.5m to 2.2m.
[0054] By adopting the above technical scheme, since the outer diameters of the head end reduced thickness portion 2 and the tail end reduced thickness portion 6 are larger than the standard outer diameter, the wall thickness of the front end of the steel pipe is correspondingly thinned while the outer diameter of the steel pipe remains unchanged after rolling on a continuous tube rolling mill; when the tail end reduced thickness portion 6 approaches the rear end of the steel pipe, since the outer diameter of the tail end reduced thickness portion 6 is larger than the outer diameter of a standard mandrel, the wall thickness of the rear end of the steel pipe is correspondingly thinned while the outer diameter remains unchanged after rolling on a continuous tube rolling mill; finally, a steel pipe with a wall thickness of 0.20 to 0.60 mm thinner than the standard size at both ends is rolled out, thereby solving the problem of increased wall thickness at both ends of the steel pipe after rolling.
[0055] In some embodiments, please refer to Figures 1 to 4 As a specific embodiment of the stepped mandrel provided in the present application, the outer diameter of the first transition portion 3 gradually decreases from the head end thickening portion 2 to the forming portion 4, and the outer diameter of the second transition portion 5 gradually decreases from the tail end thickening portion 6 to the forming portion 4.
[0056] The lengths of the first transition portion 3 and the second transition portion 5 are 300 mm to 550 mm.
[0057] By adopting the above technical solution, the first transition portion 3 and the second transition portion 5 can achieve a buffer transition between the forming portion 4 and the head end thickening portion 2 and the tail end thickening portion 6, thereby avoiding a sudden change in wall thickness during the rolling process of the steel pipe and improving the forming quality of the steel pipe.
[0058] In some embodiments, please refer to Figures 1 to 4 As a specific embodiment of the stepped mandrel provided in the present application, the head end thickening portion 2 has an inclined frustum 21, and the outer diameter of the inclined frustum 21 gradually decreases in the direction away from the forming portion 4.
[0059] In the process of inserting the core rod body 1 into the steel pipe, the inclined frustum 21 is suitable for first contacting with the steel pipe.
[0060] By adopting the above technical solution, since the outer diameter of the small-diameter end of the inclined frustum 21 is smaller than the inner diameter of the steel pipe, the core rod body 1 can be easily and quickly aligned with the steel pipe port and inserted; at the same time, the inclined conical surface 721 also reduces the friction between the steel pipe and the core rod body 1 when the core rod body 1 moves in the steel pipe.
[0061] In some embodiments, please refer to Figures 1 to 4 As a specific embodiment of the stepped mandrel provided in the present application, the tail end reduced thickness portion 6 is provided with a boss 61, and the boss 61 protrudes outward along the axial direction of the mandrel body 1; the mounting component 7 includes a mounting seat 71, a guide column 72 and a clamping piece 73.
[0062] The mounting seat 71 is used for mounting on the continuous tube rolling mill, and is coaxially arranged with the mandrel body 1 .
[0063] One end of the guide column 72 is fixedly connected to the boss 61 , and the other end extends outwardly along the axial direction of the core rod body 1 and abuts against the mounting seat 71 ; the outer diameter of the guide column 72 is greater than the outer diameter of the boss 61 .
[0064] The clamping member 73 is hinged on the mounting seat 71 , and the axial direction of the hinge shaft of the clamping member 73 is perpendicular to the axial direction of the core rod body 1 .
[0065] When the clamping member 73 swings toward the core rod body 1 , the clamping member 73 is adapted to be clamped with the guide column 72 to prevent the mounting seat 71 and the guide column 72 from moving in opposite directions.
[0066] By adopting the above technical scheme, during the steel pipe rolling process, the mandrel body 1 is firstly inserted into the steel pipe at a set speed through the rod insertion device and runs to the position of the mounting component 7. At this time, the mounting seat 71 is engaged with the rod insertion device, and the clamping member 73 clamps and fixes the mandrel body 1 by clamping on the boss 61; then, the rod insertion device is separated from the mandrel body 1, and the mandrel body 1 is limitedly rolled under the clamping action of the mounting component 7. During the limited rolling process, the rod insertion device can return to the waiting position without occupying the rolling cycle time. After the steel pipe rolling is completed, the mounting component 7 clamps the mandrel body 1 and retreats at a high speed. After the mandrel body 1 exits the continuous rolling mill, the clamping member 73 is opened, and the transfer device can move the mandrel body 1 out of the rolling center line and enter the next limited rolling cycle, which effectively shortens the rolling cycle and improves production efficiency.
[0067] In some embodiments, please refer to Figures 1 to 4 As a specific implementation of the stepped mandrel provided in the present application, the clamping member 73 has a groove 731 , and when the clamping member 73 is clamped with the guide column 72 , the guide column 72 is suitable for being embedded in the groove 731 .
[0068] By adopting the above technical solution, the guide column 72 is embedded in the groove 731, so that the guide column 72 can be locked along the radial direction of the core rod body 1.
[0069] In some embodiments, please refer to Figures 1 to 4 As a specific embodiment of the stepped mandrel provided in the present application, the end of the clamping piece 73 facing the mandrel body 1 has a slope 732, and the slope 732 extends downwardly in a direction away from the mandrel body 1; the end of the guide column 72 facing away from the mandrel body 1 has a conical surface 721, and the conical surface 721 extends downwardly in a direction away from the mandrel body 1.
[0070] When the mounting seat 71 moves toward the guide post 72 , the inclined surface 732 is adapted to abut against the conical surface 721 .
[0071] By adopting the above technical solution, when the guide column 72 moves toward the mounting seat 71, the conical surface 721 can push up the inclined surface 732, thereby driving the clamping member 73 to swing upward; the guide column 72 continues to move toward the mounting seat 71 until the inclined surface 732 is separated from the conical surface 721, at which time the clamping member 73 swings downward due to its own gravity, thereby being clamped on the boss 61, thereby achieving automatic locking of the clamping member 73.
[0072] In some embodiments, please refer to Figures 1 to 4 As a specific embodiment of the stepped mandrel provided in the present application, the mounting seat 71 has a positioning groove 711 on the side facing the mandrel body 1; when the mounting seat 71 moves toward the guide column 72, the end of the guide column 72 facing away from the mandrel body 1 is suitable for being embedded in the positioning groove 711.
[0073] By adopting the above technical solution, during normal rolling, the guide post 72 is embedded in the positioning groove 711, which can prevent the guide post 72 from moving or swinging in its own radial direction, thereby affecting the rolling quality of the steel pipe.
[0074] In some embodiments, please refer to Figures 1 to 4 As a specific implementation of the stepped mandrel provided in the present application, an operating handle 733 is provided on the upper side of the clamping member 73 .
[0075] By adopting the above technical solution, after the steel pipe rolling is completed, the installation component 7 clamps the mandrel body 1 and retracts at high speed. After the mandrel body 1 exits the continuous rolling mill, the staff can open the clamping part 73 by holding the operating handle 733, which saves time and effort and improves production efficiency.
[0076] The technical solution adopted in the present application also provides a continuous tube rolling mill, comprising the stepped mandrel proposed in any of the aforementioned items.
[0077] The beneficial effects of the continuous tube mill provided in this embodiment are the same as those of the aforementioned stepped mandrel, and will not be described in detail here.
[0078] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.
Claims
1. Stepped mandrel, characterized in that: include: The mandrel body is used to be inserted into the steel pipe; the mandrel body comprises a head end reduced thickness portion, a first transition portion, a forming portion, a second transition portion and a tail end reduced thickness portion which are connected in sequence; A mounting member, used for mounting on the continuous tube mill, and detachably connected to the tail end reduced thickness portion; Among them, during the rolling process of the steel pipe, the head end thickening portion and the tail end thickening portion are respectively used to expand the inner walls of the head and tail ends of the steel pipe to reduce the wall thickness of the steel pipe; the forming portion is used to abut against the inner wall of the steel pipe so that the size of the middle part of the steel pipe meets the forming standard.
2. The stepped mandrel according to claim 1, characterized in that: The outer diameters of the head end reduced thickness portion and the tail end reduced thickness portion are both larger than the outer diameter of the forming portion; and along the axis direction of the core rod body, the lengths of the head end reduced thickness portion and the tail end reduced thickness portion are both smaller than the length of the forming portion.
3. The stepped mandrel according to claim 1, characterized in that: The outer diameter of the first transition portion gradually decreases from the head end thickening portion toward the forming portion, and the outer diameter of the second transition portion gradually decreases from the tail end thickening portion toward the forming portion.
4. The stepped mandrel according to claim 1, characterized in that: The head end reduced thickness portion has an oblique frustum, and the outer diameter of the oblique frustum gradually decreases in a direction away from the forming portion; Wherein, during the process of inserting the core rod body into the steel pipe, the inclined frustum is suitable for first abutting against the steel pipe.
5. The stepped mandrel according to claim 1, characterized in that: The tail end reduced thickness portion is provided with a boss, and the boss protrudes outward along the axial direction of the core rod body; the mounting component comprises: A mounting seat, used for mounting on the continuous tube mill, and coaxially arranged with the mandrel body; A guide column, one end of which is fixedly connected to the boss, and the other end of which extends outwardly along the axial direction of the mandrel body and abuts against the mounting seat; the outer diameter of the guide column is larger than the outer diameter of the boss; and A clamping member is hinged on the mounting seat, and the axis direction of the hinge shaft of the clamping member is perpendicular to the axis direction of the mandrel body; Wherein, when the clamping member swings toward the core rod body, the clamping member is adapted to be clamped with the guide column to prevent the mounting seat and the guide column from moving in opposite directions.
6. The stepped mandrel according to claim 5, characterized in that: The clamping piece is provided with a groove, and when the clamping piece is clamped with the guide post, the guide post is adapted to be embedded in the groove.
7. The stepped mandrel according to claim 5, characterized in that: The end of the clamping piece facing the mandrel body has an inclined surface, and the inclined surface extends downwardly in a direction away from the mandrel body; the end of the guide column facing away from the mandrel body has a conical surface, and the conical surface extends downwardly in a direction away from the mandrel body; Wherein, when the mounting seat moves toward the guide column, the inclined surface is suitable for abutting against the conical surface.
8. The stepped mandrel according to claim 5, characterized in that: The mounting seat has a positioning groove on one side facing the core rod body; when the mounting seat moves toward the guide column, the end of the guide column away from the core rod body is suitable for being embedded in the positioning groove.
9. The stepped mandrel according to claim 5, characterized in that: An operating handle is arranged on the upper side of the clamping member.
10. Continuous tube mill, characterized in that: Comprising the stepped mandrel according to any one of claims 1 to 9.