Manufacturing device and manufacturing method of a metallurgical composite corrosion-resistant alloy liner pipe fitting

Abstract

This invention relates to the field of metallurgical composite corrosion-resistant alloy liner pipe fittings, and in particular to a manufacturing apparatus for such fittings. The apparatus comprises a clamping and fixing unit, a circumferential expansion unit, a hydraulic unit, a worktable unit, a heating unit, and a control unit. The clamping and fixing unit and the circumferential expansion unit are mounted on the worktable unit. The clamping and fixing unit secures the pipe to be processed on the worktable unit. The circumferential expansion unit extends into the pipe to be processed, pressing it from the inner circumference outwards, thereby bonding the liner and the base pipe. The hydraulic unit provides power to the clamping and fixing unit and the circumferential expansion unit. The heating unit heats the circumferential expansion unit and the pipe to be processed. The control unit schedules the operation of the apparatus. The invention also includes a method. This invention effectively solves the problems of protective integrity of FBE coated pipes and welding connections in engineering sites, reducing costs and improving production efficiency while ensuring the protective integrity of the pipeline.

Description

Technical Field

[0001] This invention relates to the field of metallurgical composite corrosion-resistant alloy liner pipe fittings, and in particular to a manufacturing apparatus and method for metallurgical composite corrosion-resistant alloy liner pipe fittings. Background Technology

[0002] Pipeline systems are indispensable for offshore oil and gas extraction facilities, and pipe fittings are an important component of these systems. FPSO and other offshore oil and gas extraction equipment are very expensive, have high operating costs, and require extremely stringent safety and reliability standards for pipelines.

[0003] Since the media transported by offshore oil and gas pipeline systems are mostly highly corrosive, the pipeline systems used must be protected against internal corrosion. FBE coating is the most effective, reliable, and cost-effective form of pipeline corrosion protection, and it is also the most widely used. However, FBE coating also has drawbacks. During pipeline welding, the high temperatures generated can damage the coating at the pipe ends. Therefore, FBE-coated pipelines all require protective integrity treatment.

[0004] The main methods to ensure the integrity of FBE coated pipeline protection include: flange connection, connection welding + robot internal patching, inner lining sliding sleeve connection, corrosion-resistant alloy short section connection, and corrosion-resistant alloy overlay welding connection.

[0005] The corrosion-resistant alloy short section connection method involves welding a corrosion-resistant alloy pipe short section with the same wall thickness and inner / outer diameter as the base pipe to both ends of the base pipe. Then, an overall FBE (Frost-Resistant Epoxy) inner coating is applied. During on-site installation, the connection welding is performed directly. The corrosion-resistant alloy section serves to prevent corrosion and block welding heat. This method is relatively simple, but its disadvantages include the large amount of corrosion-resistant alloy used and high cost.

[0006] Corrosion-resistant alloy surfacing connection involves welding a corrosion-resistant alloy layer onto the inner wall of a section at one end of the base pipe. Compared to corrosion-resistant alloy short joints, this method uses less corrosion-resistant alloy and is less expensive. However, its disadvantage is low production efficiency. For example, welding a 100mm long, 3-4mm thick corrosion-resistant alloy layer onto both ends of a base pipe with an outer diameter of 406mm takes approximately 10 hours (excluding the stress-relieving heating process), resulting in low production efficiency. Summary of the Invention

[0007] The purpose of this invention is to provide a manufacturing apparatus and method for metallurgical composite corrosion-resistant alloy liner pipe fittings, which mainly solves the problems existing in the prior art.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is to provide a manufacturing apparatus for metallurgical composite corrosion-resistant alloy liner pipe fittings, used to fit and composite the liner pipe onto the inner wall of the base pipe, wherein the fitted liner pipe and the base pipe form a pipe to be processed, characterized in that it includes a clamping and fixing unit, a circumferential expansion unit, a hydraulic unit, a worktable unit, a heating unit and a control unit.

[0009] The clamping and fixing unit and the circumferential expansion unit are mounted on the worktable unit; the worktable unit is provided with a circular pipe positioning slot for positioning and installing the circumferential expansion unit and the pipe to be processed; the positioned pipe to be processed is fixed on the worktable unit by the clamping and fixing unit and pressed from the outside of the circumference inward; the circumferential expansion unit extends into the inside of the pipe to be processed and squeezes the pipe to be processed from the inside of the circumference outward, thereby combining the liner and the base pipe;

[0010] The hydraulic unit is connected to the clamping and fixing unit and the circumferential expansion unit, providing them with fixing and compressing power, and driving the clamping and fixing unit and the circumferential expansion unit to move; the heating unit is used to heat the circumferential expansion unit and the pipe to be processed;

[0011] The control unit is electrically connected to the hydraulic unit and the heating unit, and schedules the operation of the hydraulic unit and the heating unit.

[0012] Furthermore, the clamping and fixing unit includes a first clamping mold and a second clamping mold; the first clamping mold and the second clamping mold have the same structure and size, and their clamping surfaces are semi-cylindrical surfaces; the curvature of the semi-cylindrical surface matches the outer diameter of the pipe to be processed; the first clamping mold and the second clamping mold move towards each other under the drive of the hydraulic unit to clamp or release the pipe to be processed.

[0013] Furthermore, the circumferential expansion unit includes an expansion module and an jacking module; the expansion module extends into the pipe to be processed and fits against the inner wall of the pipe to be processed; the shape of the jacking module matches the expansion module; the jacking module fits against the expansion module and, driven by the hydraulic unit, squeezes the expansion module; after being compressed, the expansion module squeezes the liner and the base pipe radially from the inside to the outside.

[0014] Furthermore, the expansion module includes a first expansion mold and a second expansion mold; the first expansion mold and the second expansion mold are the same size and are both provided with positioning pins;

[0015] The first expansion mold and the second expansion mold are positioned by the positioning pin to complete the mold closing, and after the mold closing, a mold-closed cylinder with frustum cavities at both ends is formed; the bottom surface of the frustum cavity faces outward; after the mold closing, the contact surface of the first expansion mold and the second expansion mold is a plane perpendicular to the end face of the mold-closed cylinder.

[0016] Furthermore, the jacking module includes a fixed punch and a moving punch; the fixed punch and the moving punch are installed opposite to each other and are both attached to the expansion module; the fixed punch is installed on the worktable unit; the moving punch is located at the opposite position of the fixed punch; the moving punch is connected to the hydraulic unit; driven by the hydraulic unit, the moving punch moves closer to the fixed punch and squeezes the expansion module.

[0017] Furthermore, the hydraulic unit includes a clamping hydraulic cylinder and a pushing hydraulic cylinder; there are multiple clamping hydraulic cylinders, all of which are driven and connected to the clamping and fixing unit, thereby fixing the pipe to be processed from the outside of the circumference; the pushing hydraulic cylinder is driven and connected to the circumferential expansion unit, thereby squeezing the pipe to be processed from the inside of the circumference outward; the clamping hydraulic cylinder and the pushing hydraulic cylinder operate according to the instructions of the control unit.

[0018] The present invention also provides a manufacturing method using the above-mentioned metallurgical composite corrosion-resistant alloy liner pipe fitting manufacturing apparatus, for fitting and bonding the liner pipe to the inner wall of the base pipe, characterized by comprising the steps of:

[0019] Step S100: Pre-process the base pipe and the liner pipe, and then fit the liner pipe into the base pipe to form the pipe to be processed;

[0020] Step S200: Select the clamping and fixing unit and the circumferential expansion unit that match the diameter of the pipe to be processed;

[0021] In step S300, the control unit is used to operate the heating unit to raise the temperature of the pipe to be processed to the composite temperature, while simultaneously heating the circumferential expansion unit; during heating, a protective gas is used to prevent oxidation of the composite surface of the base pipe and the liner pipe;

[0022] Step S400: Using the circular tube positioning slot, install the tube to be processed, the clamping and fixing unit, and the circumferential expansion unit on the worktable unit;

[0023] Step S500: Using the control unit, the hydraulic unit is manipulated to drive the clamping and fixing unit and the circumferential expansion unit to squeeze the liner and the base tube against each other, so that the liner and the base tube undergo a compound reaction under high temperature and pressure.

[0024] Step S600: Remove the pipe to be processed; using the control unit, operate the heating unit to raise the temperature of the pipe to be processed to the composite temperature, while simultaneously heating the circumferential expansion unit; during heating, use a protective gas to prevent oxidation of the composite surface of the base pipe and the liner pipe;

[0025] Step S700: Using the circular tube positioning slot, rotate the tube to be processed 90 degrees in a horizontal position and reinstall it on the worktable unit; then install the clamping and fixing unit and the circumferential expansion unit on the worktable unit.

[0026] Step S800: Using the control unit, the hydraulic unit is manipulated to drive the clamping and fixing unit and the circumferential expansion unit to squeeze the liner and the base tube, so that the liner and the base tube undergo a compound reaction under high temperature and pressure.

[0027] Step S900: Heat treatment is performed on the composite base tube and the liner tube to improve the microstructure and mechanical properties of the base tube, while restoring the solid solution strengthening of the liner tube.

[0028] Further, step S100 includes the following steps:

[0029] Step S110: The base tube is rounded, the inner surface is precision machined and ground to ensure that the inner diameter tolerance and surface roughness meet the standards.

[0030] Step S120: Use an organic solvent to degrease, clean, and dry the composite surface of the base tube and the liner tube.

[0031] Furthermore, steps S500 and S800 include the following steps:

[0032] Step S510: Using the control unit, the hydraulic unit is operated to drive the clamping and fixing unit to provide clamping pressure, and the pipe to be processed is fixed from the outside of the circumference to the inside.

[0033] Step S520: Using the control unit, the hydraulic unit is operated to drive the circumferential expansion unit to provide expansion pressure, expanding the pipe to be processed from the inner side of the circumference outward; with the cooperation of the clamping and fixing unit, the clamping pressure and the expansion pressure together press the liner and the base pipe, causing the liner to undergo plastic deformation and squeeze the inner wall of the base pipe;

[0034] Step S530: Using the control unit, the hydraulic unit is operated to drive the circumferential expansion unit and the clamping and fixing unit to maintain the clamping pressure and the expansion pressure between the liner and the base tube for a continuous metallurgical fusion time.

[0035] Step S540: Using the control unit, operate the hydraulic unit to drive the circumferential expansion unit out of the pipe to be processed, release the expansion pressure, thereby releasing the pressure between the liner and the base pipe;

[0036] In step S550, the control unit is used to operate the hydraulic unit to drive the clamping and fixing unit to release the pipe to be processed, thereby releasing the clamping pressure and facilitating disassembly.

[0037] Further, step S520 includes the following steps:

[0038] In step S521, the control unit operates the hydraulic unit to drive the circumferential expansion unit to increase the expansion pressure, thereby increasing the pressure between the liner and the base tube, causing them to adhere and begin to squeeze against each other.

[0039] Step S522: When the pressure between the liner and the base tube reaches the first pressure threshold, the control unit operates the hydraulic unit to drive the circumferential expansion unit to increase the expansion pressure, and at the same time drive the clamping and fixing unit to synchronously increase the clamping pressure.

[0040] In step S523, when the pressure between the liner and the base tube reaches the second pressure threshold, the control unit operates the hydraulic unit to maintain the output of the expansion pressure and the clamping pressure, thereby stabilizing the pressure between the liner and the base tube near the second pressure threshold.

[0041] In view of the above technical features, the present invention provides a manufacturing apparatus and method for a metallurgical composite corrosion-resistant alloy liner pipe fitting. Based on a double-layer pipe design, and through a dedicated device, a connecting pipe fitting is realized that simultaneously possesses a carbon steel layer and a corrosion-resistant alloy layer, with the interlayer bonded as a metallurgical composite. Compared with the prior art, it has significant advantages: by utilizing this double-layer pipe fitting for prefabricated connection with an FBE-coated pipe, the problem of the protective integrity of the FBE-coated pipe and the welding connection problem on the engineering site can be effectively solved. Compared with corrosion-resistant alloy short sections and corrosion-resistant alloy overlay welding technology, this technology reduces costs and improves production efficiency while ensuring the protective integrity of the pipeline. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the system connection of a preferred embodiment of the manufacturing apparatus for metallurgical composite corrosion-resistant alloy liner pipe fittings of the present invention;

[0043] Figure 2 This is a schematic diagram of a preferred embodiment of the manufacturing apparatus for metallurgical composite corrosion-resistant alloy liner pipe fittings of the present invention;

[0044] Figure 3This is a top view of the expansion module in a preferred embodiment of the manufacturing apparatus for the metallurgical composite corrosion-resistant alloy liner pipe fittings of the present invention.

[0045] Figure 4 yes Figure 3 Longitudinal section along section AA;

[0046] Figure 5 A schematic diagram of the assembly and installation of a preferred embodiment of the manufacturing apparatus for metallurgical composite corrosion-resistant alloy liner pipe fittings of the present invention;

[0047] Figure 6 This is a flowchart of a preferred embodiment of the manufacturing method of the manufacturing apparatus for metallurgical composite corrosion-resistant alloy liner pipe fittings of the present invention;

[0048] Figure 7 This is a flowchart of a sub-method of the extrusion composite process in a preferred embodiment of the manufacturing method of the manufacturing apparatus for metallurgical composite corrosion-resistant alloy liner pipe fittings of the present invention.

[0049] In the diagram: 100 - clamping and fixing unit, 200 - circumferential expansion unit, 300 - hydraulic unit, 400 - worktable unit, 500 - heating unit, 600 - control unit, 700 - pipe to be processed;

[0050] 101 - First clamping mold; 102 - Second clamping mold;

[0051] 210 - Expansion module, 211 - First expansion mold, 212 - Second expansion mold, 213 - Positioning pin;

[0052] 220 - Ejection module, 221 - Fixed punch, 222 - Moving punch;

[0053] 301 - Clamping hydraulic cylinder; 302 - Pushing hydraulic cylinder;

[0054] 401-Round pipe fitting positioning groove

[0055] 701 - Liner, 702 - Base pipe. Detailed Implementation

[0056] The present invention will be further described below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0057] Please see Figures 1 to 5This invention discloses a manufacturing apparatus for a metallurgical composite corrosion-resistant alloy liner pipe fitting, used to fit and composite a liner 701 onto the inner wall of a base pipe 702, the fitted liner 701 and the base pipe 702 forming a pipe 700 to be processed. The liner 701 is a corrosion-resistant alloy pipe, and the base pipe 702 is a carbon steel pipe.

[0058] The liner 701 fitting can be made of Inconel 625 nickel-based corrosion-resistant alloy pipe with an outer diameter of Φ308mm, a wall thickness of 3mm, and a length of 300mm. Alternatively, it can be made of Inconel 625 nickel-based corrosion-resistant alloy sheet with a wall thickness of 3mm, cut to a length of 300mm and a width of 967.6mm. The 300*967.6mm sheet is welded and rolled into a cylinder and then fixed by a loose weld to form a transition cylinder with a diameter of 308mm. The base pipe 702 fitting has an outer diameter of Φ325mm, a wall thickness of 8mm, an inner diameter of 309mm, and a length of 300mm. It is made of Q345B low-alloy steel, hot-rolled, normalized, seamless pipe.

[0059] As shown in the figure, a preferred embodiment of the present invention includes a clamping and fixing unit 100, a circumferential expansion unit 200, a hydraulic unit 300, a worktable unit 400, a heating unit 500, and a control unit 600.

[0060] The workbench unit 400 serves as the base of the manufacturing apparatus, arranged horizontally, with a circular tube positioning slot 401 on its upper surface. The circumferential expansion unit 200 and the tube to be processed 700 are positioned on the surface of the workbench unit 400 using the circular tube positioning slot 401, and then assembled. The clamping and fixing unit 100 is also mounted on the workbench unit 400, located around the tube to be processed 700. In operation, the clamping and fixing unit 100 retracts inward, pressing from the outer circumference inward to clamp and fix the tube to be processed 700 onto the workbench unit 400. Meanwhile, the expansion unit 200 extends into the tube to be processed 700, squeezing it from the inner circumference outward, thereby pressing the liner 701 and the base tube 702 together to establish a high-pressure environment. The hydraulic unit 300 is the power source for the clamping and fixing unit 100 and the circumferential expansion unit 200, driving their operation and providing power to fix and extrude the tube 700 to be processed. The heating unit 500 heats the circumferential expansion unit 200 and the tube 700 to establish a high-temperature environment during extrusion. This, combined with the high-pressure environment established by the clamping and fixing unit 100 and the circumferential expansion unit 200, promotes the bonding between the liner 701 and the base tube 702. The control unit 600 is the core of the manufacturing apparatus control; it is electrically connected to the hydraulic unit 300 and the heating unit 500, scheduling the operation of the hydraulic unit 300, such as controlling the opening and closing of the hydraulic system and configuring operating parameters, thereby driving the clamping and fixing unit 100 and the circumferential expansion unit 200, while simultaneously scheduling the operation of the heating unit 500. The heating unit 500 can be a medium-frequency induction heating device, a resistance heating furnace, or a gas furnace.

[0061] The clamping and fixing unit 100 is further composed of a first clamping mold 101 and a second clamping mold 102. The first clamping mold 101 and the second clamping mold 102 have the same structure and size, and are installed opposite each other, forming a clamping space between them that matches the shape of the pipe 700 to be processed. Specifically, the clamping surfaces of both the first clamping mold 101 and the second clamping mold 102 are semi-cylindrical surfaces. The curvature of this semi-cylindrical surface matches the outer diameter of the pipe 700 to be processed. The movable ends of the two clamping hydraulic cylinders 301 in the hydraulic unit 300 are respectively connected to the first clamping mold 101 and the second clamping mold 102, driving the first clamping mold 101 and the second clamping mold 102 to move. When the clamping hydraulic cylinders 301 are activated, the first clamping mold 101 and the second clamping mold 102 move towards each other, thereby clamping or placing the pipe 700 to be processed between them, preventing it from yielding or radial displacement. When the clamping hydraulic cylinder 301 resets, the pipe to be processed 700 is released. In this embodiment, the length of the first clamping mold 101 and the second clamping mold 102 is 300mm, and the diameter of the cylindrical clamping surface of the mold is 325mm.

[0062] The circumferential expansion unit 200 includes an expansion module 210 and an ejection module 220. The expansion module 210 consists of a first expansion mold 211 and a second expansion mold 212. The first expansion mold 211 and the second expansion mold 212 are the same size and both are equipped with locating pins 213. The first expansion mold 211 and the second expansion mold 212 are positioned using the locating pins 213, and then interlock to form a closed-end cylinder with frustum-shaped cavities at both ends. The outer diameter of the cylinder matches the inner diameter of the pipe 700 to be processed. The bottom surface of the frustum-shaped cavities faces outwards, and after mold closing, the contact surface between the first expansion mold 211 and the second expansion mold 212 is a plane, which is perpendicular to the end face of the closed-end cylinder. In the initial expansion state, the closed-end expansion module 210 extends into the pipe 700 to be processed, fitting against the inner wall of the pipe 700. In this embodiment, the length of the first expansion mold 211 and the second expansion mold 212 is 300mm, the outer diameter of the mold closing cylinder is 300mm, the diameter of the top surface of the end frustum cavity is 25mm, and the taper of the frustum is 45 degrees.

[0063] The ejector module 220 consists of a fixed punch 221 and a moving punch 222. The fixed punch 221 is mounted on the worktable unit 400 and fits against the lower end of the expansion module 210. The shape of the fixed punch 221 matches the frustum cavity at the lower end of the expansion module 210, is embedded and fixed at the center of the worktable unit 400, and remains stationary during expansion. The moving punch 222 is mounted opposite to the fixed punch 221, fits against the upper end of the expansion module 210, and is connected to the hydraulic unit 300. The shape of the moving punch 222 matches the frustum cavity at the upper end of the expansion module 210. In this embodiment, both the fixed punch 221 and the moving punch 222 are conical structures, and the taper is the same as the taper of the frustum cavities at both ends of the molded cylinder formed after the first expansion mold 211 and the second expansion mold 212 are closed. The bottom surface of the cone of the fixed punch 221 faces downward, and the bottom surface of the cone of the moving punch 222 faces upward. During the expansion process, the moving punch 222 is driven downward by the pusher hydraulic cylinder 302 in the hydraulic unit 300, approaching the lower fixed punch 221. As the fixed punch 221 and the moving punch 222 approach each other, they push aside the first expansion mold 211 and the second expansion mold 212, separating them and pressing the inner wall of the tube 700 to be processed radially from the inside to the outside, thereby pressing the liner 701 against the base tube 702. After the liner 701 yields circumferentially, it continues to apply pressure to the inner wall of the outer wall of the base tube 702. Under certain temperature conditions, the pressure between the liner 701 and the base tube 702 causes the outer wall of the liner 701 to undergo metallurgical bonding with the inner wall of the base tube 702. In this embodiment, the taper of the fixed punch 221 and the moving punch 222 is 45 degrees, the small end diameter is 55 mm, and the large end diameter is 224 mm.

[0064] The hydraulic unit 300 includes a clamping hydraulic cylinder 301 and a pushing hydraulic cylinder 302. The number of clamping hydraulic cylinders matches the number of clamping molds in the clamping and fixing unit 100, which is two in this embodiment. These two cylinders are driven and connected to the first clamping mold 101 and the second clamping mold 102, respectively, to push the first clamping mold 101 and the second clamping mold 102 closer together, thereby fixing the pipe 700 to be processed from the outer circumference. The pushing hydraulic cylinder 302 is driven and connected to the circumferential expansion unit 200, specifically to the moving punch 222, pushing the moving punch 222 towards the fixed punch 221, generating an expansion pressure from the inner circumference outwards. Both the clamping hydraulic cylinder 301 and the pushing hydraulic cylinder 302 are controlled by the control unit 600 and operate according to the instructions of the control unit 600. In this embodiment, the hydraulic unit 300 provides a system pressure of 60 MPa, a maximum clamping force output of 1200 tons, and a maximum pushing force output of 1200 tons.

[0065] Please see Figure 6 The present invention also provides a manufacturing method using the above-mentioned metallurgical composite corrosion-resistant alloy liner pipe fitting manufacturing apparatus, for fitting and bonding the liner pipe to the inner wall of the base pipe. A preferred embodiment includes the following steps:

[0066] Step S1: Pre-treat the base pipe and liner.

[0067] The base pipe and the liner pipe are pretreated separately to form the pipe to be processed.

[0068] Step S11: Pre-treat the inner surface of the base tube.

[0069] The base tube is rounded, its inner surface is precision-machined and ground to ensure that its inner diameter tolerance and surface roughness meet the standards. In this embodiment, the diameter tolerance is less than or equal to ±0.02 mm, and the surface roughness Ra is less than or equal to 0.8 μm.

[0070] Step S12, Clean the composite surface

[0071] Organic solvents are used to degrease, clean, and dry the composite surfaces of the base tube and liner to ensure that the composite surfaces meet the composite process standards.

[0072] Step S13: Install the base pipe and liner pipe.

[0073] Insert the liner into the base tube, aligning the two ends of the base tube and the liner.

[0074] Step S2: Adapt the processing unit.

[0075] Based on the diameter of the pipe to be processed, select clamping and fixing units and circumferential expansion units that match its dimensions. Specifically, the inner diameter of the clamping surfaces of the first and second clamping dies matches the outer diameter of the base pipe, while the outer diameters of the first and second expansion dies match the inner diameter of the liner pipe, ensuring that the outer diameter is smaller than the inner diameter of the liner pipe, but the diameter difference is no greater than 2mm. Simultaneously, the lengths of the closing cylinders of the base pipe fitting, the liner pipe fitting, and the first and second expansion dies are the same. The difference between the inner diameter of the base pipe fitting and the outer diameter of the liner pipe fitting is less than or equal to 1mm.

[0076] Step S3, first heating.

[0077] The control unit manipulates the heating unit to raise the temperature of the pipe to be processed to the composite temperature, while simultaneously heating the circumferential expansion unit. This ensures that the pipe remains stable during the expansion process, preventing a temperature drop due to heat conduction to the first and second expansion dies. A protective gas is used during heating to prevent oxidation of the composite surface of the base pipe and liner.

[0078] In this embodiment, the base tube is heated to 1150 degrees Celsius and the liner tube is heated to 1200 degrees Celsius using the medium-frequency induction heating device of the heating unit. At the same time, the circumferential expansion unit is heated to 1050 degrees Celsius using the gas furnace in the heating unit.

[0079] Step S4: Install the pipe to be processed.

[0080] Using the circular tube positioning slots on the workbench unit, the base tube, liner tube, clamping and fixing unit, and circumferential expansion unit are positioned in sequence and then assembled and installed on the workbench unit.

[0081] Specifically, a high-temperature release agent is applied to the conical portions of the fixed and moving punches in the circumferential expansion unit, as well as to the expansion surface of the closing cylinder formed by the first and second expansion dies. Next, the pipe to be processed is placed on the worktable unit, between the first and second clamping dies in the clamping and fixing unit. Then, the first and second expansion dies in the circumferential expansion unit are closed and placed inside the pipe to be processed, above the fixed punch, and then the moving punch is placed. When the closing cylinder is placed on the fixed punch, the lower end face of the closing cylinder maintains a certain distance from the composite worktable surface. The first and second expansion dies are fixedly connected using locating pins when they are closed. After installation, the axes of the fixed punch, closing cylinder, base pipe, and liner pipe are aligned.

[0082] Step S5, first extrusion compounding.

[0083] Using the control unit, the hydraulic unit drives the clamping and fixing unit and the circumferential expansion unit to squeeze the liner and the base tube against each other, causing the liner and the base tube to undergo a complex reaction under high temperature and pressure.

[0084] Step S6, second heating.

[0085] Remove the pipe to be processed. After the first extrusion bonding, the temperature of the pipe will drop, so a second heating is required to ensure the bonding effect. Using the control unit, operate the heating unit to raise the temperature of the pipe to be processed back to the bonding temperature, while simultaneously heating the circumferential expansion unit. During heating, a protective gas is used to prevent oxidation of the bonding surfaces of the base pipe and the liner.

[0086] In this embodiment, the medium-frequency induction heating device of the heating unit is used to heat the pipe to be processed after the first composite process to 1150 degrees Celsius. At the same time, the gas furnace in the heating unit is used to heat the circumferential expansion unit to 1050 degrees Celsius.

[0087] Step S7: Install the pipe to be processed.

[0088] Using the circular tube positioning slot on the worktable unit, the tube to be processed, the clamping and fixing unit, and the circumferential expansion unit are positioned in sequence, and then assembled and installed on the worktable unit.

[0089] Because both the clamping and fixing unit and the circumferential expansion unit contain only two sub-dies, the resulting extrusion pressure is not uniformly distributed along the circumference. It tends to favor the clamping direction of the first and second clamping dies, which is also the separation direction of the first and second expansion dies. Therefore, to balance the pressure difference, during this installation, the pipe to be processed is rotated 90 degrees horizontally and then reinstalled on the workbench unit. This ensures that the second extrusion is perpendicular to the first extrusion, compensating for any longitudinal composite gaps that may have been created during the first extrusion due to the circumferential movement of the first and second expansion dies, resulting in better composite quality.

[0090] Step S8, second extrusion compounding.

[0091] Using the control unit, the hydraulic unit drives the clamping and fixing unit and the circumferential expansion unit to squeeze the liner and the base tube against each other, causing the liner and the base tube to undergo a complex reaction under high temperature and pressure.

[0092] Step S9, heat treatment

[0093] In scenarios where the liner is an alloy tube, the composite base tube and liner are removed, and then heat-treated to improve the microstructure and mechanical properties of the base tube, while restoring the solid solution strengthening of the liner, resulting in the final product. In scenarios where the liner is a sheet metal roll welded together, Inconel 625 welding wire is first used to fill the gaps caused by extrusion expansion, followed by heat treatment.

[0094] Please see Figure 7 The first extrusion (step S5) and the second extrusion (step S8) described above include the following sub-steps:

[0095] Step S51: Clamp the pipe fitting to be processed.

[0096] Using the control unit, multiple clamping hydraulic cylinders in the hydraulic unit are operated to drive the corresponding first and second clamping molds in the clamping and fixing unit. These molds adhere to the pipe to be processed from the outside along the circumferential direction, providing clamping pressure from the outside inwards along the circumferential direction, thus fixing the pipe to be processed on the worktable. The initial clamping pressure is 50 tons.

[0097] Step S52: Extrude the pipe to be processed.

[0098] Using the control unit, the hydraulic cylinder in the hydraulic unit is operated to press the moving punch against the fixed punch. As the moving punch approaches the fixed punch, its conical surface first engages with the frustum cavity at the top of the die-forming cylinder, then continues to descend. The first and second expansion molds in the expansion module are separated, expanding the tube to be processed from the inner circumference outwards, providing expansion pressure. Under the combined action of the clamping pressure provided by the clamping and fixing unit and the expansion pressure of the circumferential expansion unit, the liner and base tube are compressed, promoting the composite reaction.

[0099] Step S521, the circumferential expansion unit expands to provide extrusion pressure.

[0100] In the first stage, the control unit operates the hydraulic unit, driving the circumferential expansion unit to increase the expansion pressure. The liner and the base pipe come into contact and begin to squeeze each other, with the squeezing pressure continuously increasing. In this embodiment, when the expansion pressure reaches 45 tons, in the scenario where the liner is an alloy pipe, the liner undergoes plastic deformation and squeezes the inner wall of the base pipe. In the scenario where the liner is a plate rolled and welded pipe, the weld cracks due to incomplete welding, and after the corrosion-resistant alloy layer of the liner combines with the base pipe, a longitudinal gap is formed in the inner lining layer.

[0101] In step S522, the circumferential expansion unit and the clamping and fixing unit simultaneously increase the extrusion pressure.

[0102] Once the pressure between the liner and the base tube reaches the first pressure threshold, the control unit operates the hydraulic unit to simultaneously increase the expansion pressure by driving the circumferential expansion unit and the clamping and fixing unit. At this point, the extrusion pressure rises further.

[0103] In this embodiment, the first pressure threshold is 50 tons, which is consistent with the clamping pressure.

[0104] Step S523: The set extrusion pressure is reached.

[0105] When the pressure between the liner and the base tube reaches the second pressure threshold, the control unit operates the hydraulic unit to maintain the output of expansion pressure and clamping pressure, thereby stabilizing the pressure between the liner and the base tube near the second pressure threshold, at which point the pressure no longer rises further.

[0106] In this embodiment, the second pressure threshold is 1161 tons, corresponding to a pressure of 20 MPa between the base pipe and the liner. Under this pressure and temperature, the metallurgical composite reaction begins.

[0107] Step S53: Maintain the extrusion pressure.

[0108] Using the control unit, the hydraulic unit drives the circumferential expansion unit and the clamping and fixing unit to maintain clamping pressure and expansion pressure between the liner and the base tube, and to maintain the metallurgical fusion time.

[0109] Depending on the materials of the base pipe and the liner, the metallurgical fusion time is between 10 and 30 minutes.

[0110] Step S54: Release the squeezing pressure.

[0111] Using the control unit, the push hydraulic cylinder in the hydraulic unit is operated to drive the moving punch away from the fixed punch and out of the pipe to be processed, thereby releasing the pressure between the liner and the base pipe.

[0112] Step S55: Release the pipe to be processed.

[0113] Using the control unit, multiple clamping hydraulic cylinders in the hydraulic unit are operated to drive the first clamping mold and the second clamping mold in the clamping and fixing unit respectively, moving them away from the pipe to be processed, releasing the clamping pressure, and facilitating disassembly.

[0114] In scenarios where the liner is an alloy tube, its performance was checked: The composite strength of the composite tube was sampled and tested. The results showed good interfacial bonding, with the interlayer bonding being metallurgical bonding, and the bonding strength exceeding 300 MPa. Regarding element diffusion, from the 625 nickel-based alloy layer to the carbon steel base tube layer, the content of elements such as chromium, nickel, and molybdenum decreased, while the iron content increased. Diffusion of elements such as chromium, nickel, and molybdenum was clearly visible in the 625 nickel-based alloy layer, with chromium carbides mainly precipitating at the grain boundaries, with a diffusion distance of approximately 40 μm.

[0115] When the liner is made of rolled and welded sheet metal, its performance is checked: the composite pipe made of corrosion-resistant alloy plate should have an interlayer bonding strength higher than 300MPa. Moreover, compared with seamless corrosion-resistant alloy pipe, it is easier to obtain materials, has lower processing costs, and lower requirements for the hydraulic system.

[0116] In terms of application, a metallurgical composite pipe with an outer diameter of Φ325mm and a length of 300mm, processed using this technology, is sawn into 100mm short sections, which are then welded to pipe fittings with an outer diameter of Φ325mm and a wall thickness of 8mm. After that, FBE internal coating and pipe end beveling are carried out in sequence, which can solve the problems of pipe fitting connection welding and FBE coating protection integrity on the construction site.

[0117] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A manufacturing apparatus for a metallurgical composite corrosion-resistant alloy liner pipe fitting, used to fit and composite a liner pipe onto the inner wall of a base pipe, wherein the fitted liner pipe and the base pipe form a pipe fitting to be processed, characterized in that, It includes a clamping and fixing unit, a circumferential expansion unit, a hydraulic unit, a worktable unit, a heating unit, and a control unit; The clamping and fixing unit and the circumferential expansion unit are mounted on the worktable unit; the worktable unit is provided with a circular pipe positioning slot for positioning and installing the circumferential expansion unit and the pipe to be processed; the positioned pipe to be processed is fixed on the worktable unit by the clamping and fixing unit and pressed from the outside of the circumference inward; the circumferential expansion unit extends into the inside of the pipe to be processed and squeezes the pipe to be processed from the inside of the circumference outward, thereby combining the liner and the base pipe; The hydraulic unit is connected to the clamping and fixing unit and the circumferential expansion unit, providing them with fixing and compressing power, and driving the clamping and fixing unit and the circumferential expansion unit to move; the heating unit is used to heat the circumferential expansion unit and the pipe to be processed; The control unit is electrically connected to the hydraulic unit and the heating unit, and schedules the operation of the hydraulic unit and the heating unit; The clamping and fixing unit includes a first clamping mold and a second clamping mold; the first clamping mold and the second clamping mold have the same structure and size, and their clamping surface is a semi-cylindrical surface; the curvature of the semi-cylindrical surface matches the outer diameter of the pipe to be processed; the first clamping mold and the second clamping mold move towards each other under the drive of the hydraulic unit to clamp or release the pipe to be processed; The circumferential expansion unit includes an expansion module and an jacking module; the expansion module extends into the pipe to be processed and fits against the inner wall of the pipe to be processed; the shape of the jacking module matches the expansion module; the jacking module fits against the expansion module and, driven by the hydraulic unit, squeezes the expansion module; after being compressed, the expansion module squeezes the liner and the base pipe radially from the inside to the outside; The expansion module includes a first expansion mold and a second expansion mold; the first expansion mold and the second expansion mold are the same size and are both provided with positioning pins; The first expansion mold and the second expansion mold are positioned by the positioning pin to complete the mold closing, and after the mold closing, a mold-closed cylinder with frustum cavities at both ends is formed; the bottom surface of the frustum cavity faces outward; after the mold closing, the contact surface of the first expansion mold and the second expansion mold is a plane perpendicular to the end face of the mold-closed cylinder; The jacking module includes a fixed punch and a moving punch; the fixed punch and the moving punch are installed opposite each other and are both attached to the expansion module; the fixed punch is installed on the worktable unit; the moving punch is located at the opposite position of the fixed punch; the moving punch is connected to the hydraulic unit; driven by the hydraulic unit, the moving punch moves closer to the fixed punch and squeezes the expansion module.

2. The manufacturing apparatus for metallurgical composite corrosion-resistant alloy liner pipe fittings according to claim 1, characterized in that, The hydraulic unit includes clamping hydraulic cylinders and pushing hydraulic cylinders; there are multiple clamping hydraulic cylinders, all of which are driven and connected to the clamping and fixing unit, thereby fixing the pipe to be processed from the outside of the circumference; the pushing hydraulic cylinders are driven and connected to the circumferential expansion unit, thereby squeezing the pipe to be processed from the inside of the circumference outward; the clamping hydraulic cylinders and the pushing hydraulic cylinders operate according to the instructions of the control unit.

3. A method for manufacturing pipe fittings using the manufacturing apparatus of the metallurgical composite corrosion-resistant alloy liner as described in claim 1, for fitting and bonding the liner to the inner wall of a base pipe, characterized in that, Includes the following steps: Step S100: Pre-process the base pipe and the liner pipe, and then fit the liner pipe into the base pipe to form the pipe fitting to be processed; Step S200: Select the clamping and fixing unit and the circumferential expansion unit that match the diameter of the pipe to be processed; Step S300: Using the control unit, the heating unit is operated to raise the temperature of the tube to be processed to the composite temperature, while the circumferential expansion unit is heated; during heating, a protective gas is used to prevent oxidation of the composite surface of the base tube and the liner tube; Step S400: Using the circular tube positioning slot, install the tube to be processed, the clamping and fixing unit, and the circumferential expansion unit on the worktable unit; Step S500: Using the control unit, the hydraulic unit is manipulated to drive the clamping and fixing unit and the circumferential expansion unit to squeeze the liner and the base tube against each other, so that the liner and the base tube undergo a compound reaction under high temperature and pressure. Step S600: Remove the pipe to be processed; using the control unit, operate the heating unit to raise the temperature of the pipe to be processed to the composite temperature, while simultaneously heating the circumferential expansion unit; during heating, use a protective gas to prevent oxidation of the composite surface of the base pipe and the liner pipe; Step S700: Using the circular tube positioning slot, rotate the tube to be processed 90 degrees in a horizontal position and reinstall it on the worktable unit; then install the clamping and fixing unit and the circumferential expansion unit on the worktable unit. Step S800: Using the control unit, the hydraulic unit is manipulated to drive the clamping and fixing unit and the circumferential expansion unit to squeeze the liner and the base tube, so that the liner and the base tube undergo a compound reaction under high temperature and pressure. Step S900: Heat treatment is performed on the composite base tube and the liner tube to improve the microstructure and mechanical properties of the base tube, while restoring the solid solution strengthening of the liner tube.

4. The manufacturing method according to claim 3, characterized in that, Step S100 includes the following steps: Step S110: The base tube is rounded, the inner surface is precision machined and ground to ensure that the inner diameter tolerance and surface roughness meet the standards. Step S120: Use an organic solvent to degrease, clean, and dry the composite surface of the base tube and the liner.

5. The manufacturing method according to claim 3, characterized in that, Steps S500 and S800 include the following steps: Step S510: Using the control unit, the hydraulic unit is operated to drive the clamping and fixing unit to provide clamping pressure, and the pipe to be processed is fixed from the outside of the circumference to the inside. Step S520: Using the control unit, the hydraulic unit is operated to drive the circumferential expansion unit to provide expansion pressure, expanding the pipe to be processed from the inner side of the circumference outward; with the cooperation of the clamping and fixing unit, the clamping pressure and the expansion pressure together press the liner and the base pipe, causing the liner to undergo plastic deformation and squeeze the inner wall of the base pipe; Step S530: Using the control unit, the hydraulic unit is operated to drive the circumferential expansion unit and the clamping and fixing unit to maintain the clamping pressure and the expansion pressure between the liner and the base tube for a continuous metallurgical fusion time. Step S540: Using the control unit, operate the hydraulic unit to drive the circumferential expansion unit out of the pipe to be processed, release the expansion pressure, thereby releasing the pressure between the liner and the base pipe; In step S550, the control unit is used to operate the hydraulic unit to drive the clamping and fixing unit to release the pipe to be processed, thereby releasing the clamping pressure and facilitating disassembly.

6. The manufacturing method according to claim 5, characterized in that, Step S520 includes the following steps: In step S521, the control unit operates the hydraulic unit to drive the circumferential expansion unit to increase the expansion pressure, thereby increasing the pressure between the liner and the base tube, causing them to adhere and begin to squeeze against each other. Step S522: When the pressure between the liner and the base tube reaches the first pressure threshold, the control unit operates the hydraulic unit to drive the circumferential expansion unit to increase the expansion pressure, and at the same time drive the clamping and fixing unit to synchronously increase the clamping pressure. In step S523, when the pressure between the liner and the base tube reaches the second pressure threshold, the control unit operates the hydraulic unit to maintain the output of the expansion pressure and the clamping pressure, thereby stabilizing the pressure between the liner and the base tube near the second pressure threshold.

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