Four-roll centering large-diameter steel pipe socket forming manufacturing equipment and cold pressing forming method

Abstract

The present application belongs to the technical field of steel pipe processing equipment, and particularly relates to a four-roll centering large-diameter steel pipe socket forming manufacturing equipment and a cold pressure forming method. The equipment comprises a supporting structure, a limiting structure, a forming mechanism and a power mechanism; the socket upper profiling roller, the socket lower profiling roller, the side centering roller a and the side centering roller b of the forming mechanism form a four-roll centering clamping structure; three groups of supporting oil cylinders with pressure sensors are arranged below the socket lower profiling roller, and a hydraulic lifting pipe supporting mechanism is arranged at the discharge end. During processing, the steel pipe is positioned and radially centered by the four rollers, and the turnover oil cylinder and the limiting wheel realize bidirectional axial locking; the hydraulic motor drives the roller body to drive the steel pipe to feed and extrude forming; the pressure sensor collects signals, and the lifting height of the supporting oil cylinder and the hydraulic lifting pipe supporting mechanism is synchronously adjusted to suppress the self-weight sagging deformation of the steel pipe. The present application effectively reduces the socket ovality and wall thickness deviation, can be adapted to the integrated cold pressure forming of 600-6000mm pipe diameter steel pipe sockets, and improves the steel pipe forming quality and production efficiency.

Description

Technical Field

[0001] This invention belongs to the technical field of steel pipe processing equipment, specifically relating to a four-roll centering large-diameter steel pipe socket forming manufacturing equipment and a cold pressing forming method. Background Technology

[0002] Large-diameter steel pipes are widely used in key projects such as municipal water supply and drainage, agricultural water diversion, and oil and gas transportation. Socket connections have become the mainstream connection technology in pipeline construction due to their convenient assembly, strong sealing performance, and low maintenance costs. The forming accuracy and structural stability of the steel pipe socket directly determine the quality of the pipeline connection and its safety. Roll forming is a classic process for processing large-diameter steel pipe sockets. It uses rotating rollers to extrude and plastically deform the metal at the pipe end, expanding the diameter and pressing out the socket's arc and conical surface. Currently, mainstream double-roller steel pipe socket forming equipment relies on upper and lower roller clamping for positioning. When processing large-diameter, long steel pipes, radial offset is prone to occur, resulting in excessive socket ellipticity. This leads to insufficient fit of the subsequent rubber ring assembly, easily causing pipeline leakage. Furthermore, during the roll forming of long steel pipes, the middle section is suspended, causing downward deformation under its own weight. This can easily lead to localized thinning of the pipe wall or even tearing and cracking during the forming process, resulting in large deviations in the socket wall thickness. In addition, the roller pressing equipment relies on the upper and lower rollers to evenly squeeze the tube end, which requires repeated fine-tuning of the roller gap and multiple pre-pressing passes. It cannot apply precise pressure at fixed points to the gradually tapered, arc transition section and sealing step required by the socket, making it difficult to achieve precise one-piece molding. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art and address the technical problems of large ovality, large wall thickness deviation, and difficulty in integral molding of the socket in existing equipment, this invention provides a four-roll centering large-diameter steel pipe socket forming and manufacturing equipment and a cold pressing forming method.

[0004] According to a first aspect of the present invention, a four-roll centering large-diameter steel pipe socket forming manufacturing equipment is provided, comprising a support structure, a limiting structure, a forming mechanism, and a power mechanism; the support structure includes a base fixed to the ground, a main frame rigidly fixed above the base, and a hydraulic lifting support mechanism fixed to the right end of the main frame, wherein two sets of support wheels are provided on the upper part of the crossbeam of the hydraulic lifting support mechanism; the limiting structure includes a tilting cylinder and a limiting wheel, the tilting cylinder being fixed to the left end of the main frame, and the limiting wheel being fixed to the upper end of the hydraulic lifting support mechanism; the forming mechanism includes four rollers: an upper socket forming roller, a lower socket forming roller, a side centering roller a, and a side centering roller b; the four rollers are mounted in the middle of the main frame; the upper socket forming roller and the lower socket forming roller are vertically clamped and paired, and the side centering roller a... The four rollers are symmetrically installed on the left and right sides with the side centering roller b, forming a four-roller centering clamping structure. The power mechanism includes a hydraulic station, a hydraulic motor, side centering roller support cylinder a, side centering roller support cylinder b, socket lower contouring roller support cylinder a, socket lower contouring roller support cylinder b, and socket lower contouring roller middle support cylinder. The hydraulic station is fixed on the base, and the hydraulic motor is fixed to the main frame and connected to the socket upper contouring roller by gear transmission. The side centering roller support cylinder a and side centering roller support cylinder b drive the side centering roller a and side centering roller b respectively. The lower ends of the socket lower contouring roller support cylinder a, socket lower contouring roller support cylinder b, and socket lower contouring roller middle support cylinder are all connected to the base, and the upper ends are all connected to the socket lower contouring roller. All three sets of socket lower contouring roller support cylinders are equipped with pressure sensors.

[0005] According to a second aspect of the present invention, a method for cold pressing and forming a large-diameter steel pipe socket using a four-roll centering large-diameter steel pipe socket forming and manufacturing equipment is provided, comprising the following steps:

[0006] Centering and leveling: Place the steel pipe above the lower conforming roller of the socket. Side centering rollers a and b clamp inward to complete radial centering. Together with the upper and lower conforming rollers of the socket, they form a four-roller centering structure. The hydraulic lifting support mechanism lifts the tail of the steel pipe, while the lower conforming roller and the middle support cylinder of the lower conforming roller lift the middle section of the steel pipe to correct the horizontality of the steel pipe's central axis.

[0007] Axial locking: The tilting cylinder extends and abuts against the left end face of the steel pipe, fixing the axial position of the steel pipe and restricting its axial sliding;

[0008] Feeding and extrusion: The hydraulic motor drives the upper conforming roller of the socket to rotate at a constant speed, which in turn drives the lower conforming roller, side centering roller a, and side centering roller b to rotate. Relying on the friction of the roller surface, the steel pipe is fed axially at a constant speed. The end of the steel pipe enters the arc cavity between the upper conforming roller and the lower conforming roller of the socket, realizing cold extrusion plastic deformation.

[0009] Dynamic follow-up support: During the steel pipe feeding process, the pressure sensor collects pressure signals and adjusts the lifting height of the following cylinders in real time: the lower forming roller support cylinder a, the lower forming roller support cylinder b, the middle support cylinder of the lower forming roller, and the hydraulic lifting support mechanism, so as to keep the steel pipe axis horizontal throughout the process.

[0010] Forming and unloading: After the end of the steel pipe is extruded to form a gradually rounded standard socket, the hydraulic motor reverses, and the lower forming roller support cylinders a, b, and the middle forming roller support cylinder descend to lift the pressed steel pipe.

[0011] The beneficial effects of this invention are as follows:

[0012] This invention discloses a four-roller centering large-diameter steel pipe socket forming and manufacturing equipment, which has significant technical advantages and practical value compared with traditional steel pipe socket forming equipment. This equipment adopts a four-roller centering clamping structure. Through the coordinated operation of the upper and lower conforming rollers and the double-sided centering rollers, it can effectively suppress radial offset during the steel pipe forming process, significantly reduce the ellipticity error of the large-diameter steel pipe socket, effectively improve the roundness forming accuracy of the socket, and ensure the sealing and stability of subsequent steel pipe assembly. Simultaneously, the equipment innovatively adopts a multi-point support structure with a lower conforming roller and three sets of hydraulic cylinders, which can support the pipe body in all directions, effectively reduce the vertical deformation caused by the self-weight of the large-diameter steel pipe, accurately control the socket forming thickness, significantly reduce the socket wall thickness deviation, and improve the overall uniformity and product qualification rate of the steel pipe socket forming. Furthermore, the roller curvature of the upper and lower contour rollers on this equipment precisely matches the standard pipe socket profile, enabling one-time integral forming of sockets for pipes with diameters ranging from 600 to 6000 mm. This significantly simplifies the process, effectively reduces equipment investment costs, and improves the production efficiency and processing quality of large-diameter steel pipe socket forming. This invention's large-diameter steel pipe socket cold pressing forming method utilizes the aforementioned equipment to achieve a complete processing flow. Four rollers are used for radial positioning and bidirectional limiting for axial locking. Dynamic follow-up support is implemented throughout the entire steel pipe feeding and forming process, avoiding forming defects caused by the sagging of long steel pipes. The process is continuous and controllable, eliminating the need for repeated roller adjustments and multiple pre-pressing passes, further improving the production efficiency and processing quality of large-diameter steel pipe socket forming. Attached Figure Description

[0013] Figure 1 This is a front view of a four-roll centering large-diameter steel pipe socket forming and manufacturing equipment according to the present invention.

[0014] Figure 2 This is a left view of a four-roll centering large-diameter steel pipe socket forming and manufacturing equipment according to the present invention.

[0015] Figure 3 This is a right view of a four-roll centering large-diameter steel pipe socket forming and manufacturing equipment according to the present invention.

[0016] Figure 4 This is a top view of a four-roll centering large-diameter steel pipe socket forming and manufacturing equipment according to the present invention.

[0017] Reference numerals in the attached drawings: 1-base, 2-main frame, 3-hydraulic lifting and supporting mechanism, 4-tilting cylinder, 5-limit wheel, 6-upper conforming roller of the socket, 7-lower conforming roller of the socket, 8-side centering roller a, 9-side centering roller b, 10-hydraulic station, 11-hydraulic motor, 12-side centering roller support cylinder a, 13-side centering roller support cylinder b, 14-lower conforming roller support cylinder a, 15-lower conforming roller support cylinder b, 16-middle support cylinder of the lower conforming roller of the socket, 17-steel pipe. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] like Figure 1-4 As shown, the present invention provides a four-roll centering large-diameter steel pipe socket forming and manufacturing equipment, including: a support structure, a limiting structure, a forming mechanism and a power mechanism.

[0020] The supporting structure includes: a base 1, a main frame 2, and a hydraulic lifting and supporting mechanism 3. The base 1 is fixed to the ground and provides bottom support for the entire equipment. The main frame 2 is rigidly fixed above the base 1 and supports the limiting structure, forming mechanism, and power mechanism. The hydraulic lifting and supporting mechanism 3 is fixed to the right end of the main frame 2 and supports the steel pipe 17. The hydraulic lifting and supporting mechanism 3 can slide up and down to accommodate steel pipes 17 of different diameters, reducing deformation of the steel pipe 17 under gravity. Two sets of support wheels are provided on the upper part of the crossbeam of the hydraulic lifting and supporting mechanism 3 to accommodate the rotational movement of the steel pipe 17.

[0021] The limiting structure includes: a tilting cylinder 4 and a limiting wheel 5. The tilting cylinder 4 is fixed to the left end of the main frame 2 and is used to axially limit the left end of the steel pipe 17 to prevent the steel pipe 17 from sliding to the left during the rolling process. The limiting wheel 5 is fixed to the upper end of the hydraulic lifting support mechanism 3 and is used to axially limit the right end of the steel pipe 17 to prevent the steel pipe 17 from sliding to the right during the rolling process.

[0022] The forming mechanism includes: an upper socket shaping roller 6, a lower socket shaping roller 7, a side centering roller a 8, and a side centering roller b 9. The upper socket shaping roller 6, lower socket shaping roller 7, side centering roller a 8, and side centering roller b 9 are fixed to the middle of the main frame 2 via bearings. The left end of the upper socket shaping roller 6 has a socket shaping section with a larger cross-section; except for this left-end section, the cross-sectional shape and size of the rest of the upper socket shaping roller 6 are the same. The left end of the lower socket shaping roller 7 has a socket shaping section with a smaller cross-section; except for this left-end section, the cross-sectional shape and size of the rest of the lower socket shaping roller 7 are the same. The left-end shaping sections of both the upper socket shaping roller 6 and the lower socket shaping roller 7 are detachable arc molds. The contour curvature of these molds is consistent with the standard pipe socket contour, adapting to the one-piece forming of various pipe diameter socket shapes ranging from 600 to 6000 mm. The upper and lower conforming rollers 6 and 7 form a vertical clamping feed roller, which uses the friction of the rollers to drive the steel pipe 17 axially for extrusion forming. Both the upper and lower conforming rollers 6 and 7 have internal cooling channels that circulate cooling water during operation, reducing temperature stress and lowering the risk of cold-pressing cracking at the pipe end. The lower conforming roller 7 supports the steel pipe 17, reducing vertical deformation under its own weight and lowering wall thickness deviation during socket forming. Side centering rollers a 8 and b 9 are symmetrically installed, forming a four-roller centering clamping structure with the upper and lower conforming rollers 6 and 7. This structure constrains the radial displacement of the steel pipe 17 from four directions (upper, lower, left, and right), achieving precise centering of the steel pipe 17 and reducing socket ovality. Both side centering rollers a 8 and b 9 have built-in hydraulic buffer structures for flexible centering, reducing damage to the anti-corrosion surface of the outer wall of the steel pipe 17.

[0023] The power mechanism includes: a hydraulic station 10, a hydraulic motor 11, a side centering roller support cylinder a 12, a side centering roller support cylinder b 13, a socket lower contouring roller support cylinder a 14, a socket lower contouring roller support cylinder b 15, and a socket lower contouring roller center support cylinder 16. The hydraulic station 10 is fixed to the base 1 and drives the hydraulic components to provide power. The hydraulic motor 11 is fixed to the main frame 2 and drives the socket upper contouring roller 6 to rotate via gears, causing the steel pipe 17, the socket lower contouring roller 7, the side centering roller a 8, and the side centering roller b 9 to move synchronously. The lower ends of the side centering roller support cylinders a 12 and b 13 are both connected to the base 1, and their upper ends are respectively connected to the left ends of the side centering rollers a 8 and b 9. The right ends of side centering rollers a8 and b9 are respectively equipped with hydraulic cylinders of the same structure and symmetrically distributed for support, thereby providing symmetrical support force at both ends of side centering rollers a8 and b9, reducing the deflection deformation of the roller body during operation, and ensuring centering accuracy. The lower forming roller support cylinders a14, b15, and 16 are all connected to the base 1 at their lower ends and to the lower forming roller 7 at their upper ends. All three cylinders are equipped with pressure sensors to follow the steel pipe feed and adjust the lifting height and support pressure of the corresponding cylinders and hydraulic lifting support mechanism in real time, ensuring that the lower forming roller 7 is horizontal, reducing the vertical deformation caused by the weight of the steel pipe 17, and reducing the wall thickness deviation during socket forming.

[0024] This invention provides a method for cold-pressing a large-diameter steel pipe socket using a four-roll centering system, comprising the following steps: The steel pipe 17 is hoisted and placed above the lower conforming roller 7. The hydraulic lifting and supporting mechanism 3 is adjusted to lift and support the tail of the steel pipe 17, ensuring its right end face abuts against the limiting wheel 5. Side centering rollers a 8 and b 9 clamp inward to complete radial centering, forming a four-roll centering structure with the upper conforming roller 6 and the lower conforming roller 7. The middle section of the steel pipe 17 is supported by the lower conforming roller 7 and the middle support cylinder 16, correcting the horizontal alignment of the steel pipe 17's central axis. The tilting cylinder 4 is activated to press against the left end face of the steel pipe 17, fixing its axial position and preventing axial slippage. The hydraulic motor 11 is started, driving the upper conforming roller 6 to rotate at a constant speed, which in turn drives the lower conforming roller 7, side centering roller a 8, and side centering roller b 9 to rotate. Relying on friction, the steel pipe 17 is slowly fed forward, its end gradually entering the arc-shaped cavity of the upper conforming roller 6 and the lower conforming roller 7. During the continuous feeding of the steel pipe 17, the pressure sensor collects pressure signals and adjusts the lifting height of the lower conforming roller support cylinder a 14, the lower conforming roller support cylinder b 15, the middle support cylinder 16, and the hydraulic lifting support mechanism 3 in real time, always keeping the axis of the steel pipe 17 horizontal and suppressing vertical deformation caused by its own weight. Under the pressure of the upper conforming roller 6 and the lower conforming roller 7, the end of the steel pipe 17 undergoes uniform plastic deformation, forming a gradually curved standard socket in one extrusion process. Once processing is complete, hydraulic motor 11 reverses, side centering rollers a8 and b9, upper and lower conforming rollers 6 and 7 are released, lower conforming roller support cylinders a14 and b15 and lower conforming roller center support cylinder 16 descend, and the pressed steel pipe 17 is hoisted and removed.

[0025] The control method in this application is automatic control through a controller. The control circuit of the controller can be implemented by simple programming by those skilled in the art and is common knowledge in the field. This part is not the innovation of this invention. Furthermore, this application is mainly used to protect the structure, shape and their combination. Therefore, this application will not explain the control method and circuit connection in detail. The device is powered by an external power supply.

[0026] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A four-roll centering large-diameter steel pipe socket forming and manufacturing equipment, characterized in that, The system includes a support structure, a limiting structure, a forming mechanism, and a power mechanism. The support structure comprises a base fixed to the ground, a main frame rigidly fixed above the base, and a hydraulic lifting support mechanism fixed to the right end of the main frame. Two sets of support wheels are installed on the upper part of the crossbeam of the hydraulic lifting support mechanism. The limiting structure includes a tilting cylinder and limiting wheels. The tilting cylinder is fixed to the left end of the main frame, and the limiting wheels are fixed to the upper end of the hydraulic lifting support mechanism. The forming mechanism includes four rollers: an upper conforming roller for the socket, a lower conforming roller for the socket, and a lower conforming roller for the socket. The four rollers include a side centering roller a and a side centering roller b; the four roller bearings are assembled in the middle of the main frame; the upper and lower conforming rollers of the socket are vertically clamped and paired, and the side centering rollers a and b are symmetrically installed on the left and right sides. The four rollers together form a four-roller centering clamping structure; the power mechanism includes a hydraulic station, a hydraulic motor, a side centering roller support cylinder a, a side centering roller support cylinder b, a lower conforming roller support cylinder a, a lower conforming roller support cylinder b, and a middle support cylinder for the lower conforming roller. The hydraulic station is fixed on the base, and the hydraulic motor is fixed on the main frame and connected to the conforming roller on the socket by gear transmission; Side centering roller support cylinders a and b drive side centering rollers a and b respectively; the lower ends of the lower bearing support cylinders a, b, and the middle support cylinder of the lower bearing profile roller are all connected to the base, and the upper ends are all connected to the lower bearing profile roller. All three sets of lower bearing profile roller support cylinders are equipped with pressure sensors.

2. The four-roll centering large-diameter steel pipe socket forming and manufacturing equipment according to claim 1, characterized in that, The left ends of both the upper and lower conforming rollers are equipped with detachable arc conforming section molds, the outline of which matches the outline of the standard pipe socket; both side centering rollers a and b have built-in hydraulic buffer structures; and cooling channels are opened inside both the upper and lower conforming rollers.

3. The four-roll centering large-diameter steel pipe socket forming and manufacturing equipment according to claim 1, characterized in that, The hydraulic lifting support mechanism can slide up and down to adapt to steel pipes of different diameters; the pressure sensors configured in the lower conforming roller support cylinder a, lower conforming roller support cylinder b, and the middle support cylinder of the lower conforming roller are used to follow the steel pipe feed and adjust the lifting height and support pressure of the corresponding cylinders and the hydraulic lifting support mechanism in real time.

4. A method for cold-pressing a large-diameter steel pipe socket using the equipment described in any one of claims 1-3, characterized in that, Includes the following steps: Centering and leveling: Place the steel pipe above the lower conforming roller of the socket. Side centering rollers a and b clamp inward to complete radial centering. Together with the upper and lower conforming rollers of the socket, they form a four-roller centering structure. The hydraulic lifting support mechanism lifts the tail of the steel pipe, while the lower conforming roller and the middle support cylinder of the lower conforming roller lift the middle section of the steel pipe to correct the horizontality of the steel pipe's central axis. Axial locking: The tilting cylinder extends and abuts against the left end face of the steel pipe, fixing the axial position of the steel pipe and restricting its axial sliding; Feeding and extrusion: The hydraulic motor drives the upper conforming roller of the socket to rotate at a constant speed, which in turn drives the lower conforming roller, side centering roller a, and side centering roller b to rotate. Relying on the friction of the roller surface, the steel pipe is fed axially at a constant speed. The end of the steel pipe enters the arc cavity between the upper conforming roller and the lower conforming roller of the socket, realizing cold extrusion plastic deformation. Dynamic follow-up support: During the steel pipe feeding process, the pressure sensor collects pressure signals and adjusts the lifting height of the following cylinders in real time: the lower forming roller support cylinder a, the lower forming roller support cylinder b, the middle support cylinder of the lower forming roller, and the hydraulic lifting support mechanism, so as to keep the steel pipe axis horizontal throughout the process. Forming and unloading: After the end of the steel pipe is extruded to form a gradually rounded standard socket, the hydraulic motor reverses, and the lower forming roller support cylinders a, b, and the middle forming roller support cylinder descend to lift the pressed steel pipe.

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