Reducer pipe machining method, oil and gas hose connector and manufacturing method of oil and gas hose connector

Abstract

The invention relates to the field of pipe manufacturing, in particular to a reducer pipe machining method, an oil and gas hose connector and a manufacturing method thereof.The method comprises the steps that a circular pipe is subjected to gradient heating, so that the material yield strength of a pipe section to be subjected to diameter shrinkage of the circular pipe is distributed in a gradient mode in the axial direction of the circular pipe, and the gradient direction of the material yield strength is opposite to the diameter shrinkage direction; the circular pipe subjected to gradient heating is fed into a reducing die, and the reducing die is used for reducing the diameter of the circular pipe; the wall thickness change rate of the reducing pipe section is monitored, and the material flow rate is obtained according to a pre-stored wall thickness change rate-material flow rate mapping table; and the output pressure of a press is adjusted according to the material flow rate, so that the deformation rate of the reducing pipe section in the reducing mold is matched with the material flow rate. According to the reducer pipe machining method, the oil and gas hose connector and the manufacturing method of the oil and gas hose connector, reducing deformation is accurately controlled, and the concentricity precision of the reducing pipe section and the assembling coaxiality consistency of the oil and gas hose connector are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of pipe manufacturing, and in particular to a method for processing a reducer pipe, an oil and gas hose connector and a manufacturing method thereof. Background Art

[0002] In the oil and gas transportation sector, hose fittings are critical connecting components, and their structural strength and sealing performance are directly related to the safety and reliability of the pipeline system. Oil and gas hose fittings are typically assembled from a core tube, a central sleeve, and a side sleeve with a reducer. The central and side sleeves are coaxially sleeved onto the core tube. This special structure requires the reducer to have extremely high concentricity accuracy (the error must be controlled within a few threads) after the reduction process to ensure that the side sleeves meet assembly requirements with the central sleeve and the core tube.

[0003] Currently, to achieve extremely high concentricity accuracy, reducer pipe sections are machined. This processing method results in material waste and significantly increases product manufacturing costs. Alternatively, a press-fit reduction die can be used. A press applies axial pressure to the round tube, causing it to plastically deform under the constraints of the reduction die, thereby reducing the diameter of the pipe fitting. However, the traditional press-fit reduction die processing method has significant technical bottlenecks: on the one hand, the pressure output of the press is difficult to precisely control, which can easily lead to uneven force on the reducer pipe section during the reduction process; on the other hand, the structural design of the reduction die has limited ability to suppress concentricity errors, making it difficult to control the concentricity error within a very small range (within a few wires) in actual processing. This technical limitation makes it difficult for the concentricity accuracy of the reduced pipe after processing to meet the assembly requirements of oil and gas hose connectors, affecting the overall performance and service life of the connector. Summary of the Invention

[0004] To this end, the purpose of the present invention is to overcome the problem that the concentricity of the reduced diameter pipe section processed by the existing medium-pressure machine in conjunction with the reducing die cannot meet the requirements, and to provide a reducer processing method, an oil and gas hose joint and its manufacturing method, to accurately control the reduction deformation, improve the concentricity accuracy of the reduced diameter pipe section, and the assembly coaxiality consistency of the oil and gas hose joint.

[0005] In the first aspect, in order to solve the above technical problems, the present invention provides a method for processing a reducer tube, comprising: Gradual heating is performed on the circular tube so that the yield strength of the material of the section of the circular tube to be reduced is distributed in a gradient along the axial direction of the circular tube, and the gradient direction of the yield strength of the material is opposite to the direction of reduction; The round tube after gradient heating is sent into a diameter reducing die, and the diameter of the round tube is reduced by the diameter reducing die; monitoring the wall thickness change rate of the reduced diameter pipe section and obtaining the material flow rate according to a pre-stored wall thickness change rate-material flow rate mapping table; The output pressure of the press is adjusted according to the material flow rate, so that the deformation rate of the reduced diameter pipe section in the reduced diameter die matches the material flow rate.

[0006] In one embodiment of the present invention, the output pressure of the press is adjusted according to the material flow rate so that the deformation rate of the reduced pipe section in the reducing die matches the material flow rate, including obtaining the axial displacement change of the reducing die per unit time, and determining the actual deformation rate of the reduced pipe section based on the axial displacement change; obtaining the material flow rate according to a pre-stored wall thickness change rate-material flow rate mapping table, and taking the material flow rate as the target deformation rate; calculating the difference between the target deformation rate and the actual deformation rate; if the difference is greater than 0, increasing the output pressure of the press; if the difference is less than 0, reducing the output pressure of the press.

[0007] In one embodiment of the present invention, the increasing step size of the output pressure of the press is 0.5 MPa; or / and the decreasing step size of the output pressure of the press is 0.3 MPa.

[0008] In one embodiment of the present invention, the pipe section to be reduced in diameter of the circular pipe is heated by a segmented induction heating system, wherein the segmented induction heating system includes at least three independently controlled induction coils, each of which sequentially covers the pipe section to be reduced in diameter along the axial direction; wherein the power of the induction coil gradually increases along the reduction direction of the pipe section to be reduced in diameter.

[0009] In one embodiment of the present invention, when the section of the circular tube to be reduced in diameter is heated by the segmented induction heating system, the outer wall of the circular tube is wrapped with a ceramic fiber insulation sleeve.

[0010] In one embodiment of the present invention, the axial temperature difference of the gradient heating is 50°C~150°C, and the surface temperature T of the tube section to be reduced when entering the reduction die satisfies: T≥T0-50°C; T0 represents the recrystallization temperature of the material.

[0011] In one embodiment of the present invention, the reducing die includes a die core and a die sleeve, the cone angle θ of the continuous cone surface of the die core is 5°~15°, the guide cone angle β of the die sleeve is 3°~10°, and θ>β.

[0012] In a second aspect, to solve the above technical problems, the present invention further provides an oil and gas hose connector, comprising a core tube, a sleeve, and a reducer, wherein the reducer is manufactured by the reducer processing method; The sleeve and the reducer are both coaxially sleeved outside the core tube; wherein the sleeve is located in the axial middle of the core tube and is fixed thereto, and the two reducers are respectively located on both sides of the sleeve and are fixed thereto.

[0013] In one embodiment of the present invention, shoulders are symmetrically provided on both sides of the sleeve in the axial direction, and an extension is provided on the sleeve on the axial outside of the shoulder, with an inclined transition between the shoulder and the extension; The end pipe section of the reducer located near the reducer section surrounds the extension portion, and the end surface of the end pipe section is located at the inclined transition and welded to the sleeve; A radial gap is provided between the reducer and the core tube; and a reducer cavity is formed between the reducer section of the reducer and the outer tube wall of the core tube.

[0014] In a third aspect, in order to solve the above technical problems, the present invention also provides a method for manufacturing an oil and gas hose connector, which is used to manufacture the oil and gas hose connector. The manufacturing method includes: Provide core tube; Providing a sleeve, wherein the sleeve is coaxially sleeved outside the core tube and located in the middle of the core tube in the axial direction; Welding the core tube to the sleeve at both axial ends; Providing a reducer, wherein the reducer is coaxially sleeved outside the core tube, and an end pipe section of the reducer located near the reducer section surrounds the extension portion; The reducer and the sleeve are welded at the inclined transition.

[0015] The above technical solution of the present invention has the following beneficial effects compared with the prior art: The reducer processing method, oil and gas hose connector, and manufacturing method thereof described in the present invention achieve concentricity accuracy of the reduced diameter pipe section within ±0.03 mm through the coordinated optimization of gradient heating and dynamic pressure regulation, thereby resolving the technical problem of insufficient concentricity of the reduced diameter pipe section during processing, meeting the high-precision assembly requirements of the oil and gas hose connector, and improving the overall performance and reliability of the oil and gas hose connector.

[0016] Gradient heating is used to create a gradient in the yield strength of the circular tube section to be reduced along the axial direction, with the gradient direction opposite to the reduction direction. This allows for directional flow control during the reduction process. Compared to no heating or uniform heating, this method effectively avoids excessive thinning on the inner side of the reduced section (closest to the mold) due to concentrated compressive stress, and insufficient thinning on the outer side due to delayed stress transfer. This allows the cross-sectional shape of the reduced tube to more closely resemble an ideal circle, keeping the concentricity error of the reduced section within a very small range (e.g., ±0.02mm), significantly improving the coaxial consistency during assembly with the core tube and sleeve.

[0017] The press output pressure is dynamically adjusted based on the real-time monitoring of the wall thickness change rate to match the deformation rate of the reduced pipe section with the material flow rate. This closed-loop control mechanism can effectively suppress excessive local deformation caused by pressure fluctuations or uneven mold gaps, avoid eccentricity caused by uneven force during the reduction process, further ensure the geometric symmetry of the reduced pipe section, and meet the stringent requirements of oil and gas hose joints for high-precision concentricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the contents of the present invention more clearly understood, the present invention is further described in detail below based on specific embodiments of the present invention in conjunction with the accompanying drawings.

[0019] Figure 1 Flowchart of a method for processing a reducer tube in a preferred embodiment of the present invention; Figure 2 This is a schematic structural diagram of a reducer obtained by processing in a preferred embodiment of the present invention; Figure 3 Flow chart of adjusting the output pressure of a press according to the material flow rate in a preferred embodiment of the present invention; Figure 4 This is a structural diagram of an oil and gas hose connector in a preferred embodiment of the present invention; Figure 5 for Figure 4 A schematic diagram of an axial cross-section of the oil and gas hose connector shown; Figure 6 Flowchart of a method for manufacturing an oil and gas hose connector in a preferred embodiment of the present invention.

[0020] Description of the accompanying drawings: 2-core tube; 4-sleeve; 41-shoulder; 42-extension; 43-welding point; 6-reducing tube; 61-end tube section; 8-radial gap; 10-reducing cavity. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the accompanying drawings and specific embodiments so that those skilled in the art can better understand the present invention and implement it. However, the embodiments are not intended to limit the present invention.

[0022] The purpose of the embodiments of the present invention is to solve the problem in the prior art that the concentricity of the reduced diameter pipe section processed by the medium-pressure machine in conjunction with the reducing die cannot meet the requirements. Because this problem cannot be solved, the edge sleeve used for the oil and gas hose connector can only be manufactured by machining, but the material waste of machining is extremely great, resulting in high manufacturing costs.

[0023] Example 1: The present invention uses a press machine with a reducing die to process a portion of a round tube into a reduced diameter tube section, thereby solving the problem that the concentricity of the reduced diameter tube section does not meet the requirements and replacing machining to produce a reducing sleeve for oil and gas hose connectors. Figure 1 As shown, an embodiment of the present invention discloses a method for processing a variable diameter pipe, comprising: S100, performing gradient heating on the circular tube so that the yield strength of the material of the section of the circular tube to be reduced is distributed in a gradient along the axial direction of the circular tube, and the gradient direction of the yield strength of the material is opposite to the direction of reduction; S200, sending the round tube after gradient heating into a diameter reducing die, and reducing the diameter of the round tube by the diameter reducing die; S300, monitoring the wall thickness change rate of the reduced diameter pipe section, and obtaining the material flow rate according to a pre-stored wall thickness change rate-material flow rate mapping table; S400: Adjusting the output pressure of the press according to the material flow rate, so that the deformation rate of the reduced diameter pipe section in the reduced diameter die matches the material flow rate.

[0024] In specific application scenarios, before the round tube is reduced in diameter using a press and a reducing die, the section of the round tube to be reduced is heated. The purpose of heating is to change the yield strength of the material. The higher the temperature, the lower the yield strength. The yield strength of the material is the critical stress value when the metal material undergoes plastic deformation, that is, the minimum stress required for the material to enter the plastic deformation stage from the elastic deformation stage. The lower the yield strength, the easier it is for the material to undergo plastic deformation.

[0025] The purpose of gradient heating is to provide a controllable mechanical environment for subsequent diameter reduction deformation by regulating the distribution of material yield strength; the explanation of the gradient direction of material yield strength being opposite to the diameter reduction direction is as follows: taking the positive direction of the X-axis as the axial direction of the circular tube as an example, the diameter of the reduced tube section obtained after the diameter reduction treatment gradually decreases "from left to right", that is, the left end is the large diameter end and the right end is the small diameter end; while the yield strength gradually increases "from left to right", that is, the yield strength of the small diameter section is the lowest and the yield strength of the large diameter end is the highest; the lower the yield strength, the easier it is to plastically deform; conversely, the higher the yield strength, the less likely it is to plastically deform. Specifically, refer to Figure 2 As shown in the figure, with B→A as the reduction direction, the diameter at position A of the reduction pipe section is the smallest, and the diameter at position B is the largest; through gradient heating, the material yield strength at position A is the lowest, and it is most susceptible to plastic deformation; the material yield strength at position B is the highest, and it is least susceptible to plastic deformation.

[0026] Through gradient heating, the yield strength of the circular tube section to be reduced is distributed in a gradient along the axial direction, with the gradient direction opposite to the reduction direction. This results in a lower yield strength on the inside (closest to the mold) and a higher yield strength on the outside (away from the mold). This internal stress difference drives directional material flow, balancing the internal and external deformation rates and preventing uneven wall thickness. Compared to no heating or uniform heating methods, this method effectively avoids excessive thinning on the inside (closest to the mold) of the reduced section due to concentrated compressive stress and insufficient thinning on the outside (away from the mold) due to delayed stress transfer. The cross-sectional shape of the reduced tube is closer to an ideal circle, thus controlling the concentricity error of the reduced section to an extremely small range (e.g., ±0.02mm), significantly improving the coaxial consistency during assembly with the core tube and sleeve.

[0027] Subsequently, the round tube after gradient heating is sent into the reducing die. The press and the reducing die cooperate to perform controllable plastic deformation of the section of the round tube to be reduced under the constraint of the reducing die to ensure the uniformity of the wall thickness of the reduced section.

[0028] During the reduction process, the wall thickness change data of the reduced pipe section is obtained in real time to provide feedback basis for dynamic pressure control. In specific application scenarios, 4 to 8 distributed optical fiber sensors (such as FBG fiber grating sensors) are evenly arranged along the circumferential direction at the position of the reduced pipe section in the reduction mold, with a sensor spacing of ≤10mm and a coverage length of ≥50mm. The wall thickness of the reduced pipe section is measured in real time by the optical fiber sensor, and the wall thickness change per unit time is calculated to obtain the wall thickness change rate.

[0029] A wall thickness change rate-material flow rate mapping table is established through experiments or simulations, which includes multiple sets of preset wall thickness change rates and corresponding material flow rate data; the material flow rate is extracted from the mapping table based on the obtained wall thickness change rate, and the output pressure of the press is adjusted according to the material flow rate, so that the deformation rate of the reduced pipe section in the reduced die matches the material flow rate.

[0030] It should be noted that the wall thickness change rate is the amount of reduction in wall thickness in the reduced diameter section of a circular tube per unit time, measured in mm / s. A distributed fiber optic sensor array collects real-time wall thickness data for this section, and the wall thickness difference at adjacent time points is calculated as the wall thickness change rate. The material flow rate is the speed at which the material moves along the axial direction (in the direction of reduction) of the circular tube per unit time, i.e., the length of time the material flows into the reduced diameter section per unit time, measured in mm / s.

[0031] While gradient heating can preset the material's yield strength distribution, the actual shrinking process is subject to dynamic changes in material flow rate, influenced by factors such as temperature fluctuations and mold friction. By real-time monitoring of the wall thickness change rate (reflecting the deformation rate), the press pressure is dynamically adjusted to ensure a consistent match between the two, avoiding excessive thinning on the inside due to excessive pressure or insufficient thinning on the outside due to insufficient pressure. The yield strength gradient formed by gradient heating provides the fundamental driving force for material flow, while dynamic pressure regulation further precisely controls flow direction and rate. The combination of these two ensures wall thickness uniformity of ±0.02mm in the shrinking pipe section.

[0032] Based on the above embodiments, Figure 3 As shown, the output pressure of the press is adjusted according to the material flow rate so that the deformation rate of the reduced pipe section in the reducing die matches the material flow rate, including obtaining the axial displacement change of the reducing die per unit time, and determining the actual deformation rate of the reduced pipe section according to the axial displacement change; obtaining the material flow rate according to a pre-stored wall thickness change rate-material flow rate mapping table, and taking the material flow rate as the target deformation rate; calculating the difference between the target deformation rate and the actual deformation rate; if the difference is greater than 0, increasing the output pressure of the press; if the difference is less than 0, reducing the output pressure of the press.

[0033] In a specific application scenario, when a press cooperates with a reducing die to perform a reducing process, the press moves axially toward the tube. The tube is constrained by the reducing die and undergoes radial reduction. A high-precision linear displacement sensor (such as a magnetostrictive displacement sensor) is installed on the reducing die drive mechanism (such as a hydraulic cylinder or servo motor screw) of the press to monitor the axial feed displacement Δx of the reducing die in real time. This is used to calculate the feed rate of the reducing die (i.e., the feed displacement per unit time). Since the deformation rate of the tube is slightly lower than the feed rate of the reducing die, a deformation efficiency coefficient λ=0.8~0.95 is introduced. The actual deformation rate of the reduced tube section is calculated by taking the product of the deformation efficiency coefficient and the feed rate of the reducing die.

[0034] If the difference between the target deformation rate and the actual deformation rate is greater than 0, it means that the current deformation rate is too low and the press output pressure is increased; conversely, if the difference between the target deformation rate and the actual deformation rate is less than 0, it means that the current deformation rate is too high and the press output pressure is reduced; if the difference between the two is within the set threshold range (such as ±0.005mm / s), the current pressure is maintained.

[0035] Based on the above embodiment, the press output pressure is increased in increments of 0.5 MPa; or / and, the press output pressure is decreased in increments of 0.3 MPa. Adjusting the pressure with a fixed increment allows for rapid response to deviations between the material flow rate and deformation rate. Furthermore, this fixed increment creates a "stepped" pressure adjustment, aligning pressure changes with material flow conditions and avoiding wall thickness fluctuations or mold impact caused by sudden pressure changes.

[0036] In addition, the optimal combination of increasing the step size to 0.5 MPa and reducing the step size to 0.3 MPa was determined through orthogonal experiments. Increasing the step size by 0.5 MPa can cover more than 80% of the scenarios where the material flow rate is insufficient; reducing the step size by 0.3 MPa can avoid more than 90% of the risk of excessive wall thickness.

[0037] Based on the above embodiment, the section of the circular tube to be reduced in diameter is heated by a segmented induction heating system, wherein the segmented induction heating system includes at least three independently controlled induction coils, each of which sequentially covers the section of the tube to be reduced in diameter along the axial direction; wherein the power of the induction coil gradually increases along the reduction direction of the section of the tube to be reduced in diameter.

[0038] In a specific application scenario, a segmented induction heating system is used to pre-treat the section of the circular tube to be reduced in diameter. The system includes at least three (preferably three to five) independently controlled induction coils, which are arranged in sequence along the axial direction of the circular tube, namely the first induction coil, the second induction coil, and the third induction coil (and so on). Each coil is controlled by an independent power supply and temperature closed-loop control module; the first induction coil covers the large-diameter end (i.e., the thicker side after the future reduction, corresponding to the outer side); the second induction coil covers the middle of the tube section; the third induction coil covers the small-diameter end (i.e., the thinner side after the future reduction, corresponding to the inner side); the first induction coil is set to the lowest power to ensure the lowest temperature at the large-diameter end (such as power P1); the second induction coil is set to medium power to ensure the moderate temperature in the middle (such as power P2); and the third induction coil (small-diameter end) is set to the highest power to ensure the highest temperature at the small-diameter end (such as power P3), with P1 < P2 < P3. The segmented induction heating system heats the round tube in independent segments. The axial temperature distribution can be flexibly set and adjusted in real time as required to achieve the optimal match between the yield strength gradient and the diameter reduction process.

[0039] Furthermore, when the segmented induction heating system is used to heat the section of the circular tube to be reduced in diameter, the outer wall of the circular tube is wrapped with a ceramic fiber insulation sleeve. The thermal insulation performance of the ceramic fiber insulation sleeve suppresses radial heat diffusion, establishes a stable axial temperature gradient, reduces external thermal interference, and then regulates the material yield strength distribution and drives directional plastic deformation.

[0040] It should be noted that: in terms of position, the round tube is inside, the ceramic fiber insulation sleeve wraps the round tube, and the induction coil is arranged around the ceramic fiber insulation sleeve. The number of turns, diameter and spacing of the induction coil are designed according to the heating power, frequency and round tube size.

[0041] Based on the above embodiment, the axial temperature difference of the gradient heating is 50°C-150°C, and the surface temperature T of the tube section to be reduced when entering the reduction die satisfies: T≥T0-50°C; T0 represents the recrystallization temperature of the material.

[0042] The axial temperature difference refers to the temperature difference between one axial end of the pipe section to be reduced. This axial temperature difference drives the yield strength gradient, balances the deformation rates of the inner and outer walls, and determines wall thickness uniformity. In the high-temperature zone, near the recrystallization temperature, atomic diffusion increases, dislocation movement resistance decreases, and yield strength decreases significantly. In the low-temperature zone, atomic diffusion decreases, dislocation movement resistance increases, and yield strength approaches its original value. An axial temperature difference of 50°C to 150°C balances deformation rate and stability. In some scenarios, an axial temperature difference of 100°C achieves optimal wall thickness uniformity in the reduced section, significantly improving the life of the reduction die.

[0043] The surface temperature T refers to the surface temperature of the round tube when the diameter-reducing section enters the diameter-reducing die. Its lower limit is the material recrystallization temperature T0 minus 50°C, which ensures the material's plastic deformation ability, avoids thermal cracking and work hardening, and controls the stability of the microstructure. When T≥T0-50°C, the atomic diffusion capacity is sufficient to support dynamic recrystallization and eliminate work hardening during the diameter reduction process. The resistance to dislocation movement is significantly reduced, and the material flow stress is reduced by 50%~80%.

[0044] In one embodiment of the present invention, the reducing die includes a die core and a die sleeve, the cone angle θ of the continuous cone surface of the die core is 5°~15°, the guide cone angle β of the die sleeve is 3°~10°, and θ>β.

[0045] In specific application scenarios, the continuous cone angle θ of the die core refers to the angle between the cone surface of the compression section of the reduction die and the axial direction. The continuous cone angle θ determines the balance between the axial compression force and radial flow resistance during tube reduction, affecting the uniformity of material flow and die life. By adjusting θ, the ratio of the axial and circumferential components of the metal flow in the tube can be changed, thereby regulating the wall thinning rate and avoiding localized excessive thinning or thickening. When θ is within the range of 5° to 15°, the ratio of the axial and circumferential components of the metal flow in the tube is moderate, forming a stable "shear-extrusion" composite deformation mode, ensuring uniform material flow along the circumference into the reduction section and avoiding wall thickness fluctuations caused by uneven flow.

[0046] The die sleeve's guide taper angle, β, refers to the angle between the die's entrance cone and the axial direction. It determines the initial contact state of the tube as it enters the reduction die, impacting alignment accuracy and deformation stability. Optimizing β reduces friction between the tube and the reduction die, avoiding cracking or wrinkling caused by localized stress concentration. When β is within the 3° to 10° range, the contact area between the tube and the die is moderate, resulting in low friction (friction coefficient μ ≤ 0.15), reducing the risk of surface scratches and improving the finished product's surface quality.

[0047] The core taper angle θ (5°-15°) must be greater than the sleeve guide taper angle β (3°-10°). This ensures a smoother guiding effect at the entry section (sleeve) of the reduction die, while more concentrated deformation occurs in the compression section (core), creating a graded deformation pattern of "guiding first, then compression." Furthermore, a θ > β setting creates a smoother stress gradient within the reduction die, buffering the material flow differences between the inside and outside of the tube and preventing cracking or wrinkling caused by stress concentration.

[0048] Example 2: Reference Figure 4 and Figure 5 As shown, the embodiment of the present invention discloses an oil and gas hose connector, comprising a core tube 2, a sleeve 4 and a reducer 6, wherein the reducer 6 is manufactured by the reducer processing method described above; The sleeve 4 and the reducer 6 are both coaxially sleeved outside the core tube 2; wherein, the sleeve 4 is located in the axial middle of the core tube 2 and is fixed thereto, and the two reducers 6 are respectively located on both sides of the sleeve 4 and are fixed thereto.

[0049] Specifically, the sleeve 4 is symmetrically provided with shoulders 41 on both sides of the axial direction, and the sleeve 4 is provided with an extension portion 42 on the axial outside of the shoulder portion 41, and an inclined transition is formed between the shoulder portion 41 and the extension portion 42; The end pipe section 61 of the reducer 6 located near the reducer section surrounds the extension portion 42, and the end surface of the end pipe section 61 is welded to the sleeve 4 at the inclined transition. A radial gap 8 is defined between the reducer 6 and the core tube 2 ; a reducing cavity 10 is formed between the reducing section of the reducer 6 and the outer wall of the core tube 2 .

[0050] The oil and gas hose connector disclosed in the embodiment of the present invention is manufactured by the reducer processing method described in Example 1, and the concentricity accuracy is within ±0.03 mm, so that the coaxiality accuracy of the oil and gas hose connector obtained by assembling the core tube 2, the sleeve 4 and the reducer 6 is significantly improved, meeting the assembly requirements of the oil and gas hose connector.

[0051] Example 3: Reference Figure 6 As shown, an embodiment of the present invention discloses a method for manufacturing an oil and gas hose connector, which is used to manufacture the oil and gas hose connector. The manufacturing method includes: Provide core tube; Providing a sleeve, wherein the sleeve is coaxially sleeved outside the core tube and located in the middle of the core tube in the axial direction; Welding the core tube to the sleeve at both axial ends; Providing a reducer, wherein the reducer is coaxially sleeved outside the core tube, and an end pipe section of the reducer located near the reducer section surrounds the extension portion; The reducer and the sleeve are welded at the inclined transition.

[0052] The manufacturing method of the oil and gas hose joint disclosed in the embodiment of the present invention adopts the reducer processing method described in Example 1 to manufacture the reducer, and the concentricity accuracy is within ±0.03mm. The coaxiality accuracy of the oil and gas hose joint obtained by assembling the core tube 2, the sleeve 4 and the reducer 6 is significantly improved, meeting the structural strength and sealing requirements of the oil and gas hose connection.

[0053] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will appreciate that other variations or modifications can be made based on the above description. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A method for processing a reducer pipe, characterized in that: include, Gradual heating is performed on the circular tube so that the yield strength of the material of the section of the circular tube to be reduced is distributed in a gradient along the axial direction of the circular tube, and the gradient direction of the yield strength of the material is opposite to the direction of reduction; The round tube after gradient heating is sent into a diameter reducing die, and the diameter of the round tube is reduced by the diameter reducing die; monitoring the wall thickness change rate of the reduced diameter pipe section and obtaining the material flow rate according to a pre-stored wall thickness change rate-material flow rate mapping table; The output pressure of the press is adjusted according to the material flow rate, so that the deformation rate of the reduced diameter pipe section in the reduced diameter die matches the material flow rate.

2. The method for processing a reducer according to claim 1, wherein: Adjusting the output pressure of the press according to the material flow rate so that the deformation rate of the reduced diameter pipe section in the reduced diameter die matches the material flow rate, including: Obtaining the axial displacement change of the diameter-reducing die per unit time, and determining the actual deformation rate of the diameter-reducing pipe section based on the axial displacement change; Obtaining a material flow rate according to a pre-stored wall thickness change rate-material flow rate mapping table, and taking the material flow rate as a target deformation rate; Calculating a difference between the target deformation rate and the actual deformation rate; If the difference is greater than 0, increasing the output pressure of the compressor; If the difference is less than 0, the output pressure of the compressor is reduced.

3. The method for processing a reducer according to claim 2, wherein: The output pressure of the press is increased in steps of 0.5 MPa; or / and, the output pressure of the press is decreased in steps of 0.3 MPa.

4. The method for processing a reducer according to claim 1, wherein: The section of the circular tube to be reduced in diameter is heated by a segmented induction heating system, wherein the segmented induction heating system includes at least three independently controlled induction coils, each of which sequentially covers the section of the tube to be reduced in diameter along the axial direction; wherein the power of the induction coil gradually increases along the reduction direction of the section of the tube to be reduced in diameter.

5. The method for processing a reducer according to claim 4, wherein: When the section of the circular tube to be reduced in diameter is heated by the segmented induction heating system, the outer wall of the circular tube is wrapped with a ceramic fiber heat-insulating sleeve.

6. The method for processing a reducer according to claim 1 or 4, characterized in that: The axial temperature difference of the gradient heating is 50° C. to 150° C., and the surface temperature T of the tube section to be reduced when entering the reduction die satisfies: T≥T0-50° C.; T0 represents the recrystallization temperature of the material.

7. The method for processing a reducer according to claim 1, wherein: The reducing die includes a die core and a die sleeve, the cone angle θ of the continuous cone surface of the die core is 5°~15°, the guide cone angle β of the die sleeve is 3°~10°, and θ>β.

8. Oil and gas hose connector, including core tube, sleeve and reducer, characterized by: The reducer is made based on the reducer processing method according to any one of claims 1 to 7; The sleeve and the reducer are both coaxially sleeved outside the core tube; wherein the sleeve is located in the axial middle of the core tube and is fixed thereto, and the two reducers are respectively located on both sides of the sleeve and are fixed thereto.

9. The oil and gas hose connector according to claim 8, characterized in that: The sleeve is symmetrically provided with shoulders on both sides of the axial direction, and the sleeve is provided with an extension portion on the axial outer side of the shoulder, and an inclined transition is formed between the shoulder and the extension portion; The end pipe section of the reducer located near the reducer section surrounds the extension portion, and the end surface of the end pipe section is located at the inclined transition and welded to the sleeve; A radial gap is provided between the reducer and the core tube; and a reducer cavity is formed between the reducer section of the reducer and the outer tube wall of the core tube.

10. A method for manufacturing an oil and gas hose connector, for manufacturing the oil and gas hose connector according to claim 8 or 9, characterized in that: The manufacturing method includes, Provide core tube; Providing a sleeve, wherein the sleeve is coaxially sleeved outside the core tube and located in the middle of the core tube in the axial direction; Welding the core tube to the sleeve at both axial ends; Providing a reducer, wherein the reducer is coaxially sleeved outside the core tube, and an end pipe section of the reducer located near the reducer section surrounds the extension portion; The reducer and the sleeve are welded at the inclined transition.

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