A continuous straightening method for high-precision thin seamless tubes and its connecting tooling

Abstract

The present invention relates to a continuous straightening method for high-precision thin seamless tubes. Through the end plugs and tail plugs at both ends of the tubes, the straightening feeding speed and the supporting rollers cooperate, and by utilizing the rotational speed difference between the front and rear tubes during the straightening process, the self-locking and self-unlocking of the end plugs and tail plugs are completed, thereby realizing the continuous straightening of the tubes without stopping the machine and without interruption. This method can change the intermittent feeding mode of the tubes into automatic continuous straightening, enabling the ends to be more fully stressed, reducing the differences and straightening marks between the thin ends and the middle parts during the straightening process, improving the uniform consistency in the length direction of the tubes, meeting the high-precision requirements, reducing the part that needs to be cut off at the ends, and at the same time eliminating the operation of lifting the straightening rollers manually to place each tube into the straightening machine before straightening, thus improving the straightening efficiency.

Description

Technical Field

[0001] The present invention relates to a straightening method for pipe materials, in particular to a continuous straightening method for high-precision thin and seamless pipes and its connecting tooling. Background Art

[0002] At present, with the development of science and technology, while various equipment designs pursue performance advancement, more stringent requirements are also put forward in terms of size and uniformity. High-precision thin-walled seamless pipes are often used in special fields such as nuclear power, aviation, and aerospace, and more stringent requirements are imposed on the shape. Generally, the above-mentioned pipe materials need to pass through internal eddy current detection and high-standard surface dimension inspection, and even a slight change in diameter in the radial direction will result in final non-conformance or partial rejection.

[0003] During the processing of the above-mentioned pipe materials, after heat treatment, it is necessary to improve the straightness through a straightening process. The straightening machines on the market are mainly equipment based on the three-point straightening principle. By multiple groups of upper and lower straightening rolls biting into the pipe material, rotation plus radial movement is used to achieve the straightening of its entire length. However, when straightening the head and tail ends of the pipe material, there is always a section in a semi-free state. The straightening force is insufficient and uneven, resulting in certain differences in dimensions and properties between the head and tail parts and the middle section. There will be situations where the internal eddy current detection and high-standard surface dimension inspection cannot meet the requirements, leading to non-conformance or partial rejection.

[0004] By increasing the length of a single pipe material, the proportion of end rejection can be relatively reduced. However, due to reasons such as cold rolling and heat treatment of high-precision seamless pipes in other processes, the length of a single pipe material is limited and cannot be increased indefinitely. And during the straightening process, the pipe material is in a high-speed rotation process, and conventional pipe connection cannot be carried out. Simply allowing the pipe material to be continuously fed without being connected into a whole cannot achieve uniform straightening of the ends. At the same time, when multiple pipe materials are connected into a whole in a certain way, after the straightening is completed, during the discharging process, due to limited space, it is necessary to disassemble them into single pipes for discharging. The entire process is continuously completed in a very short time and is difficult to be intervened manually. Summary of the Invention

[0005] To solve the above problems, the present invention provides a continuous straightening method for high-precision thin and seamless pipes, and the specific technical solution is as follows:

[0006] A continuous straightening method for high-precision thin and seamless pipes, comprising the following steps:

[0007] Step 1: Respectively install an end plug and a tail plug at both ends of the pipe to be straightened;

[0008] Step 2: Use the feeding and conveying device to send the straight pipe to be straightened into the straightening machine. The end of the straight pipe to be straightened with an end plug faces the straightening machine. Then, the straightening machine starts to straighten. Control the distance between the two adjacent straight pipes to be straightened, and ensure that the speed of the straightening rolls of the straightening machine in the feeding direction is V1. During the straightening process, the straightening machine also drives the straight pipe to be straightened to rotate;

[0009] Step 3: Adjust the speed of the feeding and conveying device to V2, and V2 > V1. During the straightening process of the previous straight pipe to be straightened in the straightening machine, the end plug of the latter straight pipe to be straightened is inserted into the tail plug of the previous straight pipe to be straightened, and through the rotation of the previous straight pipe to be straightened, the end plug on the latter straight pipe to be straightened is connected to the tail plug on the previous straight pipe to be straightened;

[0010] Step 4: When the straight pipe to be straightened completes straightening and leaves the straightening machine, the feeding speed on the discharging and conveying device is V3, and V3 > V1. The tail plug of the straightened pipe is separated from the end plug of the pipe being straightened;

[0011] Step 5: Repeat Step 3 and Step 4 to continuously complete the straightening operation of the pipes of the same specification, and centrally remove the end plugs and tail plugs at both ends of the pipes at the discharging place.

[0012] Preferably, the end plug and the tail plug are connected by threads.

[0013] Preferably, the difference between V2 and V1 is 0.02 - 0.08 m / s; the difference between V3 and V1 is 0.02 - 0.08 m / s.

[0014] Preferably, both the feeding and conveying device and the discharging and conveying device include idler rollers and pressure rollers, and the pipe is located between the idler rollers and the pressure rollers.

[0015] Further, an annular driving groove is provided on the idler roller, and the pipe is located in the driving groove.

[0016] Among them, several annular driving teeth are provided in the driving groove.

[0017] A connecting tooling for a continuous straightening method of a high-precision thin and seamless pipe. The end plug includes an end connecting column and an end inserting column, and the tail plug includes a tail connecting column and a tail inserting column; a thread or a tapered thread is provided on the end connecting column, and a threaded hole matching the thread or a tapered threaded hole matching the tapered thread is provided on the tail connecting column. The diameters of the end plug and the tail plug are the same as the diameter of the straight pipe to be straightened.

[0018] Preferably, several end opening grooves are provided on the end inserting column; several tail opening grooves are provided on the tail inserting column;

[0019] Preferably, both the end insertion post and the tail insertion post are conical.

[0020] Preferably, a plurality of end strengthening protrusions are provided on the end insertion post; a plurality of tail strengthening protrusions are provided on the tail insertion post.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] A continuous straightening method for a high-precision thin and seamless tube provided by the present invention completes the self-locking and self-unlocking of the end plug and the tail plug by means of the end plugs and tail plugs at both ends of the tube, the straightening feeding speed and the cooperating of the idler rollers, and utilizes the rotational speed difference of the tubes before and after during the straightening process, so as to achieve continuous straightening of the tubes without stopping the machine and without interruption. Description of the Drawings

[0023] Figure 1 is a schematic diagram of Step 2;

[0024] Figure 2 is a schematic diagram of Step 3;

[0025] Figure 3 is a schematic diagram after straightening is completed;

[0026] Figure 4 is a schematic diagram of Step 4;

[0027] Figure 5 is a schematic diagram of the structure of the end plug;

[0028] Figure 6 is a schematic diagram of the structure of the tail plug;

[0029] Figure 7 is a schematic diagram of the structure of the idler roller. Detailed Embodiments

[0030] The present invention will be further described below in conjunction with the accompanying drawings.

[0031] By means of the end plugs 4 and tail plugs 5 at both ends of the tube, the straightening feeding speed and the cooperating of the idler rollers 9, and utilizing the rotational speed difference of the tubes before and after during the straightening process, the self-locking and self-unlocking of the end plug 4 and the tail plug 5 are completed, so as to achieve continuous straightening of the tubes without stopping the machine and without interruption.

[0032] This method can change the intermittent feeding mode of the tube into automatic continuous straightening, the ends of the tube are more fully stressed, reduce the differences and straightening marks between the thin and fine ends and the middle part during the straightening process, improve the uniform consistency in the length direction of the tube, meet the high-precision requirements, reduce the part that needs to be cut off at the end, and at the same time eliminate the operation of lifting the straightening rollers manually and putting the tube into the straightening machine 7 before straightening each tube, improving the straightening efficiency.

[0033] Embodiment 1

[0034] like Figures 1 to 7 As shown, a continuous straightening method for high-precision thin seamless pipes includes the following steps:

[0035] Step 1: Install the end plug 4 and the tail plug 5 into the two ends of the pipe 1 to be straightened respectively;

[0036] Step 2: Use the feeding conveying device 6 to feed the pipe 1 to be straightened into the straightening machine 7, the end of the pipe 1 to be straightened equipped with the end plug 4 faces the straightening machine 7, and then the straightening machine 7 starts straightening, the straightening roller of the straightening machine 7 drives the pipe to rotate forward, the distance between the front and rear pipes 1 to be straightened is controlled, and the speed of the straightening roller of the straightening machine 7 in the feeding direction is stabilized at V1;

[0037] Step 3: Adjust the speed of the feed conveyor 6 to V2, and V2>V1, during the straightening process of the previous tube 1 to be straightened in the straightening machine 7, the end plug 4 of the next tube 1 to be straightened is inserted into the tail plug 5 of the previous tube 1 to be straightened, and the end plug 4 on the next tube 1 to be straightened is connected with the tail plug 5 on the previous tube 1 to be straightened by the rotation of the previous tube 1 to be straightened in the straightening machine 7;

[0038] Step 4: When the pipe is straightened and leaves the straightening machine 7, the feeding speed on the discharging conveying device 8 is V3, and V3>V1, and the tail plug 5 of the straightened pipe is separated from the end plug 4 of the straightening pipe;

[0039] Step 5: Repeat steps 3 and 4 to continuously complete the straightening operation of the pipe of this specification, and remove the end plugs 4 and tail plugs 5 at both ends of the pipe at the unloading point.

[0040] The end plugs 4 and the tail plugs 5 connect the pipes to form an integral structure. When the length of a single pipe is limited, continuous straightening of multiple pipes can be achieved, which significantly reduces the end effect and improves the straightening efficiency and yield rate.

[0041] The end plug 4 and the tail plug 5 automatically realize locking and unlocking between the front and rear pipes.

[0042] The end plug 4 and the tail plug 5 are connected by a tapered thread, which is convenient for docking and tightening and loosening.

[0043] like Figure 7 As shown, the feed conveying device 6 and the discharge conveying device 8 both include a roller 9 and a pressure roller, and the pipe is located between the roller 9 and the pressure roller. The roller 9 is provided with an annular driving groove 91, and the pipe is located in the driving groove 91. The driving groove 91 can increase the contact area with the pipe and improve the friction force, and can also align the end plug 4 with the tail plug 5.

[0044] In order to further increase the frictional force and prevent the circumferential rotation of the pipe, a number of annular drive teeth 92 are provided in the drive groove 91. The drive teeth 92 increase the frictional force with the pipe and can effectively prevent the rotation of the pipe, so that the pipes on the feeding conveying device 6 and the discharging conveying device 8 can be connected to and separated from the pipe in the straightening machine 7.

[0045] Feeding conveying devices 6 and discharging conveying devices 8 are respectively provided at both ends of the straightening machine 7. The pipe on the feeding conveying device 6 is called the pipe to be straightened 1, the pipe on the straightening machine 7 is called the straightened pipe 2, and the pipe that has been straightened on the discharging conveying device 8 is called the straight pipe 3.

[0046] The speed of the feeding conveying device 6 is V2 = V1 + 0.02 m / s. During the straightening process, the straightened pipe 2 in the straightening rollers has circumferential movement, while the subsequent pipe to be straightened 1 only has axial transmission. Utilizing this difference and the design of the thread helix directions of the end plug 4 and the tail plug 5 at the end of the pipe, the tail plug 5 of the straightened pipe 2 can naturally screw into and bite with the end plug 4 at the end of the pipe to be straightened 1.

[0047] The speed of the discharging conveying device 8 is V3 = V1 + 0.03 m / s. When the idler roller 9 of the discharging conveying device 8 is conveying, the straightened pipe 3 that has been straightened has lost the circumferential rotational force of the straightening rollers, while the straightened pipe 2 being straightened is still rotating. There is a circumferential rotation difference between the straight pipe 3 and the straightened pipe 2, and this difference is just opposite to the helix direction during feeding. Utilizing this rotation difference, the end plug 4 of the straightened pipe 2 and the tail plug 5 of the straight pipe 3 can naturally unscrew, so as to realize the unlocking and separation of the straightened pipe 2 and the straight pipe 3.

[0048] Embodiment 2

[0049] As Figure 5 and Figure 6 shown, a connecting tooling for a continuous straightening method of a high-precision thin seamless pipe includes an end plug 4 and a tail plug 5. The end plug 4 includes an end connecting column 41 and an end inserting column 43, and the tail plug 5 includes a tail connecting column 51 and a tail inserting column 53; a tapered thread 42 is provided on the end connecting column 41, a tapered screw hole 52 matching the tapered thread 42 is provided on the tail connecting column 51, and the diameters of the end plug 4 and the tail plug 5 are the same as the diameter of the pipe to be straightened 1.

[0050] Both the end inserting column 43 and the tail inserting column 53 are tapered to facilitate insertion into the ends of the pipe. Among them, a number of end opening grooves 44 are provided on the end inserting column 43; a number of tail opening grooves 54 are provided on the tail inserting column 53; the end opening grooves 44 and the tail opening grooves 54 form a cross groove, so that the end inserting column 43 and the tail inserting column 53 have a certain elasticity, which can not only facilitate insertion into both ends of the pipe, but also be tightened at the observed ends.

[0051] In order to further prevent the end plug 4 and the tail plug 5 from falling off and rotating during observation, a plurality of end reinforcement protrusions 45 are provided on the end insertion column 43; a plurality of tail reinforcement protrusions 55 are provided on the tail insertion column 53. The end reinforcement protrusions 45 and the tail reinforcement protrusions 55 are both arranged along the axis, and the protrusion height is 0.2mm, so as to increase the tensioning force inside the pipe.

[0052] The technical principle of the present invention is described above in conjunction with specific embodiments. These descriptions are only for explaining the principle of the present invention and cannot be interpreted as limiting the protection scope of the present invention in any way. Based on the explanations herein, those skilled in the art can associate other specific implementations of the present invention without paying creative labor, and these methods will fall within the protection scope of the claims of the present invention.

Claims

1. A continuous straightening method for high-precision thin seamless tubes, characterized in that, it includes the following steps: Step 1: Insert the end plug (4) and the tail plug (5) into both ends of the straightening tube (1) to be straightened respectively; Step 2: Use the feeding conveying device (6) to send the straightening tube (1) to be straightened into the straightening machine (7). The end of the straightening tube (1) with the end plug (4) faces the straightening machine (7). Then the straightening machine (7) starts to straighten. Control the distance between the two straightening tubes (1) before and after, and stabilize the speed of the straightening rolls of the straightening machine (7) in the feeding direction at V1. During the straightening process of the straightening machine (7), the straightening tube (1) to be straightened is also driven to rotate; Step 3: Adjust the speed of the feeding conveying device (6) to V2, and V2 > V1. During the straightening process of the previous straightening tube (1) in the straightening machine (7), the end plug (4) of the latter straightening tube (1) is inserted onto the tail plug (5) of the previous straightening tube (1), and the end plug (4) on the latter straightening tube (1) is connected to the tail plug (5) on the previous straightening tube (1) by the rotation of the previous straightening tube (1); Step 4: When the straightening tube (1) finishes straightening and leaves the straightening machine (7), the feeding speed on the discharging conveying device (8) is V3, and V3 > V1. The tail plug (5) of the straightened pipe is separated from the end plug (4) of the pipe being straightened; Step 5: Repeat Step 3 and Step 4 to continuously complete the straightening operation of the same specification pipes. Collect the end plug (4) and the tail plug (5) at both ends of the pipe at the discharging place; The end plug (4) is threadedly connected to the tail plug (5).

2. The continuous straightening method for high-precision thin seamless tubes according to claim 1, characterized in that, the difference between V2 and V1 is 0.02 - 0.08 m / s; the difference between V3 and V1 is 0.02 - 0.08 m / s.

3. The continuous straightening method for high-precision thin seamless tubes according to claim 1, characterized in that, both the feeding conveying device (6) and the discharging conveying device (8) include idler rollers (9) and pressure rollers, and the pipe is located between the idler rollers (9) and the pressure rollers.

4. The continuous straightening method for high-precision thin seamless tubes according to claim 3, characterized in that, the idler roller (9) is provided with an annular driving groove (91), and the pipe is located in the driving groove (91).

5. The continuous straightening method for high-precision thin seamless tubes according to claim 4, characterized in that, several annular driving teeth (92) are provided in the driving groove (91).

6. The continuous straightening method for high-precision thin seamless tubes according to claim 1, characterized in that, The end plug (4) includes an end connecting column (41) and an end inserting column (43), and the tail plug (5) includes a tail connecting column (51) and a tail inserting column (53); a tapered thread (42) is provided on the end connecting column (41), and a tapered screw hole (52) matching the tapered thread (42) is provided on the tail connecting column (51). The diameters of the end plug (4) and the tail plug (5) are the same as the diameter of the straightening pipe (1) to be straightened.

7. A continuous straightening method for a high-precision thin and seamless pipe according to claim 6, characterized in that a plurality of end opening grooves (44) are provided on the end inserting column (43); a plurality of tail opening grooves (54) are provided on the tail inserting column (53).

8. A continuous straightening method for a high-precision thin and seamless pipe according to claim 6, characterized in that both the end inserting column (43) and the tail inserting column (53) are tapered.

9. A continuous straightening method for a high-precision thin and seamless pipe according to claim 6, characterized in that a plurality of end reinforcing protrusions (45) are provided on the end inserting column (43); a plurality of tail reinforcing protrusions (55) are provided on the tail inserting column (53).

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