Process for preparing pipes with different thicknesses

Abstract

The invention relates to the technical field of unequal-thickness pipe production, in particular to a process for preparing unequal-thickness pipes, which is characterized in that pipes with the same outer diameter and different inner diameters are prepared by using a pipe coiling machine according to specific requirements, and then two coaxially butted pipes with the same outer diameter and different inner diameters are annularly welded by adopting a double-beam laser welding mode to form the unequal-thickness pipes. The process of preparing the pipe by adopting a pipe coiling machine and combining with double-beam laser welding is adopted to divide the preparation and forming of the pipe with different thicknesses into two steps, the problem of influencing the quality of the pipe with different thicknesses is concentrated in a welding link, and the double-beam laser welding can be used for preheating or cleaning an oxide layer and then performing deep penetration welding, so that the problems of air holes and splashing are reduced, and the welding quality and efficiency are improved; and the requirement for the welding platform device is low, the structure of the welding platform device can be simplified, and the probability that a machine breaks down is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of unequal thickness pipe production, in particular to a process for preparing unequal thickness pipe. BACKGROUND

[0002] Unequal thickness pipe, also known as unequal thickness metal pipe fittings (such as TRB pipe, TWB welded pipe, etc.), realizes material optimized distribution by thinning or thickening in specific areas, and has become a key technology for lightweight and high performance in the fields of automobiles and aerospace. For example, in the thickened door anti-collision pipe of automobile safety structure, the roll forming technology is used to realize consistent outer diameter and gradually changing inner diameter (such as 1.6 mm→2.9 mm gradient, etc.), the thickening in the collision area improves the impact resistance, and the thinning in the non-collision area reduces the weight by about 25%-40%, thereby avoiding the thickness limitation of traditional welding area. In the new energy three-electricity system, the hot gas expansion (HMGF) integrally formed unequal thickness aluminum alloy pipe is used to reduce 12 welds, the air tightness reaches 10-9 Pa·m3 / s, the thermal conductivity is >180 W / m·K, and the integrated liquid cooling plate improves the heat management efficiency; the high-frequency resistance welding (HFW) composite laser remelting technology is used to weld the aluminum-silicon coated pipe with different thicknesses, thereby eliminating the oxidation inclusions in the coating. In the field of aerospace, the isothermal forging + electron beam process is used to weld the seamless pipe (wall thickness 1.5-3 mm) of compressor Ti-6Al-4V, thereby reducing the weight by 40% and improving the thrust-to-weight ratio by 15%. For different application fields, use purposes and material properties of the workpiece, the roll forming, hot gas expansion and composite welding processes are used to prepare the unequal thickness pipe fittings.

[0003] Tailor welded blank (TWB) is a way of welding different thicknesses / materials of flat plates in advance by laser welding, TIG welding, etc., and then forming a pipe. TWB supports the assembly of different materials, different coatings or thicknesses (such as high-strength steel + aluminum alloy), and can realize curve splicing (automobile anti-collision beam). However, when TWB is formed by welding, the weld moves to the thick plate side, resulting in local thinning of the thin plate, and the welding speed is limited (about 15 m / min for laser welding), and its application scenarios include automobile instrument panel beam and dissimilar material cooling pipe.

[0004] Tailor rolled blank (TRB) is a way of directly producing plate materials with continuously changing thickness by dynamically adjusting the rolling gap through flexible rolling, and then cutting the pipe. The use of TRB to prepare unequal thickness pipe has no weld defect at the connection, uniform structure and high surface quality, and is suitable for automobile exposed parts. Since the continuous rolling speed can reach more than 100 m / min, the cost is 30% lower than that of TWB. However, the continuous rolling process is only suitable for plate materials of the same material and width, and cannot be compatible with dissimilar metals; for different thickness mutations, the rolling speed / pressure amount needs to be accurately matched, and once the rolling speed / pressure amount is not accurately matched, cracking and other problems are likely to occur, such as cracking during the rolling process of 22MnB5 high-strength steel.

[0005] Patch plate is to bond or weld a patch on the substrate locally, and remove the patch after forming to form a variable thickness area. This process can achieve precise local thickening, and has low requirements for equipment (can directly use existing coiled pipe line without special rolling mill), but the specific operation process is complicated, the automation feasibility is low, and the preparation efficiency is low in industrial large-scale production. SUMMARY

[0006] To solve the above technical problems, the purpose of the present application is to provide a process for preparing a variable thickness pipe.

[0007] To achieve the above purpose, the present application adopts the following technical solutions: A process for preparing a variable thickness pipe, comprising the following process steps: A, material selection and preparation: according to the performance requirements and application scenarios of the variable thickness pipe, selecting appropriate raw materials; after determining the raw materials, inspecting and treating the raw materials to ensure that the chemical composition and mechanical properties of the raw materials meet the requirements; at the same time, according to the shape and size of the variable thickness pipe, cutting and pretreating the raw materials into plate materials of the required shape and size; B, pipe material preparation by coiling machine: b1, plate material pretreatment: using a flattening machine to eliminate plate material rolling residual stress to ensure the flatness of the plate material, and adjusting the pressure value of the flattening machine according to the plate thickness; b2, roll forming: 3-4 groups of double-curved roll progressive bending plate material are set for rough forming, and the curvature radius R of the plate material is from ∞ to the target value to form a pipe embryo; 2-3 groups of universal roll closed pipe blank are set for fine forming, and the opening angle of the pipe embryo is from 180° to 0° to form a pipe material; b3, welding: welding the closed mouth of the pipe material; according to the material properties, size and application field of the pipe material, selecting a suitable welding process, and the welding process includes high-frequency resistance welding, TIG welding or laser welding; b4, sizing and correction: using 3-5 groups of conical roll to cold roll the pipe material to control the outer diameter tolerance of the pipe material within the target tolerance range; using 5-7 roll inclined roll straightening machine to eliminate the bending degree of the pipe material, and the straightness is ≤0.5mm / m; b5, preparing a pipe material with the required outer diameter and inner diameter size; C, double-beam laser ring welding: c1, pipe material loading and fixing: fixing two pipe materials with the same outer diameter and different inner diameters prepared in step B on the welding platform device, and the two clamps of the welding platform device fix the two pipe materials with the same outer diameter and different inner diameters, so that the central axes of the two pipe materials coincide; c2, laser ring welding process: two laser welders are arranged in series in front and back to form double-beam laser welding, which is divided into preheating and main welding. The first beam laser welds the pipe for preheating or cleaning the oxide layer, and the second beam laser welds the pipe for deep melting welding. During the welding process, the welding platform device drives the two pipes with coinciding central axes to rotate continuously and uniformly to realize ring welding of the two pipes rotating continuously and uniformly to form a variable thickness pipe. D, blanking of the variable thickness pipe: the variable thickness pipe is taken off from the welding platform device.

[0008] Further, before step A, preliminary demand planning is carried out: comprehensively consider the multi-dimensional factors of application scene, performance requirements and preparation feasibility of the variable thickness pipe, and clearly define the performance indicators of the variable thickness pipe, including strength, stiffness, impact resistance and lightweight degree.

[0009] Further, in step A, suitable raw materials include 22MnB5 steel, aluminum alloy and metal composite material.

[0010] Further, in step b1, the pressure value of the flattening machine is 50-200KN; in step b4, the target tolerance range of the outer diameter of the pipe is ±0.1mm.

[0011] Further, the welding platform device comprises a base, a fixed chuck, a movable chuck, a rotating driver, a welding mechanism and a translation driver. The bottom surface of the base is rotatably provided with a plurality of rollers, which form a support plane between the fixed chuck and the movable chuck. The two ends of the base are provided with two supports, the fixed chuck is rotatably connected to one support, the translation driver is installed on the other support, the movable chuck is installed on the translation end of the translation driver, the fixed chuck and the movable chuck are oppositely arranged, the central axes of the fixed chuck and the movable chuck coincide, the translation driver is used to drive the movable chuck to approach or move away from the fixed chuck, the rotating driver is installed on the support and is used to drive the fixed chuck or / and the movable chuck to rotate, the welding mechanism is located above the fixed chuck and the movable chuck, and the welding mechanism comprises a mounting seat and two laser welders arranged in series in front and back.

[0012] Further, the power range of the laser welder is 1-30KW, the wavelength of the laser emitted by the laser welder is 1064nm, and the photoelectric efficiency of the laser welder is 30%-40%; the distance between the two laser welders is 0.2-2.0mm.

[0013] Further, the welding mechanism further comprises a focal length adjusting module arranged on the mounting seat and a spacing adjusting module arranged on the adjusting end of the focal length adjusting module, and the two laser welders are arranged on the two adjusting ends of the spacing adjusting module, the spacing adjusting module is used for adjusting the spacing of the two laser welders, and the focal length adjusting module is used for adjusting the focal length of the laser welder.

[0014] Further, the welding platform device further comprises a lifting driving mechanism arranged on the base, and the two supports are arranged on the lifting ends of the lifting driving mechanism.

[0015] Further, in step D, the unequal-thickness pipe is taken off from the welding platform device by the mechanical arm; the control system analyzes and determines the coordinate position of the unequal-thickness pipe on the welding platform device, calculates the optimal motion trajectory of the mechanical arm according to the coordinate position, so that the mechanical arm moves along the optimal motion trajectory and clamps and discharges the unequal-thickness pipe to the discharging position.

[0016] Further, after step D, the unequal-thickness pipe is subjected to quality detection, the mechanical arm first clamps the unequal-thickness pipe into the detection device, the detection device detects the mechanical performance of the unequal-thickness pipe, verifies whether the wall thickness and cross-sectional shape of the unequal-thickness pipe meet the design accuracy, detects whether the transition area of the variable cross-section structure is smooth, detects whether there is a welding defect or material looseness in the unequal-thickness pipe, and simulates and analyzes the performance of the unequal-thickness pipe in collision; after the detection is completed, the mechanical arm discharges the detected unequal-thickness pipe to the good product area or the defective product area.

[0017] The beneficial effects of the present application are as follows: the present application uses the pipe winding machine to prepare pipe materials with the same outer diameter and different inner diameters according to specific requirements, and then adopts the double-beam laser welding method to perform ring welding on two pipe materials with the same outer diameter and different inner diameters which are coaxially connected to form an unequal-thickness pipe, the preparation and molding of the unequal-thickness pipe are divided into two steps by using the pipe winding machine to prepare pipe materials combined with the double-beam laser welding process, the problems affecting the quality of the unequal-thickness pipe are concentrated in the welding link, the double-beam laser welding can preheat or clean the oxide layer before deep penetration welding, reduces the problems of pores and spatter, improves the welding quality and efficiency, and has low requirements for the welding platform device, can simplify the structure of the welding platform device, and reduces the probability of machine failure. BRIEF DESCRIPTION OF DRAWINGS

[0018] Fig. 1 The process flowchart of the present application is shown.

[0019] Fig. 2 The process flowchart of the pipe winding machine of the present application is shown.

[0020] Fig. 3 The process flowchart of the double-beam laser ring welding of the present application is shown.

[0021] Fig. 4This is a schematic diagram of the welding platform device of the present invention.

[0022] Explanation of reference numerals in the attached figures: 1. Base; 2. Fixed chuck; 3. Movable chuck; 4. Rotary drive; 5. Welding mechanism; 6. Translation drive; 7. Roller; 8. Lifting drive mechanism; 9. Support; 10. Pipe. Detailed Implementation To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0023] like Figs. 1 to 4 As shown, the present invention provides a process for preparing tubes of unequal thickness, which includes the following process steps: A. Material Selection and Preparation: Select appropriate raw materials based on the performance requirements and application scenarios of the unequal thickness tubes; after determining the raw materials, inspect and process them to ensure that the chemical composition and mechanical properties of the raw materials meet the requirements; at the same time, cut and pre-process the raw materials into sheets of the required shape and size according to the shape and size of the unequal thickness tubes. B. Pipe rolling machine prepares 10 pipes: b1. Sheet pretreatment: Use a leveling machine to eliminate residual stress from sheet rolling and ensure the flatness of the sheet. Adjust the pressure value of the leveling machine according to the sheet thickness. b2. Roll forming: In rough forming, 3-4 sets of hyperbolic rollers are used to progressively bend the sheet metal, and the radius of curvature R of the sheet metal is changed from ∞ to the target value to form a tube blank; in fine forming, 2-3 sets of universal rollers are used to close the tube blank, and the opening angle of the tube blank is changed from 180° to 0° to form a tube. b3. Welding: Welding the closed ends of the pipe; Select the appropriate welding process according to the material properties, size and application of the pipe. Welding processes include high-frequency resistance welding, TIG welding or laser welding. b4. Sizing and straightening: Use 3-5 sets of tapered rollers to cold roll the tube and control the outer diameter tolerance of the tube within the target tolerance range; use a 5-7 roller skew roller straightener to eliminate the curvature of the tube, and the straightness ≤0.5mm / m; b5. Prepare pipes with the required outer and inner diameters 10; C. Dual-beam laser ring welding: c1. Loading and fixing of pipe 10: Fix two pipes 10 with the same outer diameter but different inner diameter prepared in step B onto the welding platform device. The two clamps of the welding platform device fix the two pipes 10 with the same outer diameter but different inner diameter, so that the central axes of the two pipes 10 coincide. c2, laser ring welding process: two laser welders are arranged in series in front and back to form double-beam laser welding, and the double-beam laser welding is divided into preheating and main welding, the first beam laser welding preheats or cleans the oxide layer of the pipe 10, and the second beam laser welding deeply melts the pipe 10; during the welding process, the welding platform device drives the two pipe 10s with coinciding central axes to continuously and uniformly rotate, so as to realize the ring welding process forming of the two continuously and uniformly rotating pipe 10s, and form the unequal-thickness pipe; D, unequal-thickness pipe blanking: taking the unequal-thickness pipe off the welding platform device.

[0024] According to the specific needs, the pipe winding machine is used to prepare the pipe 10 with the same outer diameter and different inner diameters, and the double-beam laser welding method is used to ring weld the two coaxially butted pipe 10s with the same outer diameter and different inner diameters to form the unequal-thickness pipe. The preparation and forming of the unequal-thickness pipe are divided into two steps by using the pipe winding machine to prepare the pipe 10 combined with the double-beam laser welding process, so that the problems affecting the quality of the unequal-thickness pipe are concentrated in the welding link, the double-beam laser welding can preheat or clean the oxide layer before deep melting, which reduces the problems of pores and splashes, improves the welding quality and efficiency, and has low requirements for the welding platform device, can simplify the structure of the welding platform device, reduces the probability of machine failure, avoids the use of different molds, improves the preparation feasibility of the unequal-thickness pipe, and can meet the preparation of unequal-thickness pipes of different materials.

[0025] In this embodiment, before step A, preliminary demand planning is carried out: comprehensively consider the application scene, performance requirements and preparation feasibility of the unequal-thickness pipe and other multi-dimensional factors, and determine the performance indicators of the unequal-thickness pipe, including strength, stiffness, impact resistance and lightweight degree.

[0026] In this embodiment, in step A, suitable raw materials include 22MnB5 steel, aluminum alloy and metal composite material.

[0027] In this embodiment, in step b1, the pressure value of the flattening machine is 50-200KN; in step b4, the target tolerance range of the outer diameter of the pipe is ±0.1mm.

[0028] In the embodiment, the welding platform device comprises a base 1, a fixed chuck 2, a movable chuck 3, a rotating driver 4, a welding mechanism 5 and a translation driver 6. A plurality of roller shafts 7 are rotatably arranged on the bottom surface of the base 1, and the plurality of roller shafts 7 form a support plane between the fixed chuck 2 and the movable chuck 3. Two supports 9 are arranged at the two ends of the base 1. The fixed chuck 2 is rotatably connected to one of the supports 9. The translation driver 6 is arranged on the other support 9. The movable chuck 3 is arranged on the translation end of the translation driver 6. The fixed chuck 2 and the movable chuck 3 are oppositely arranged. The central axis of the fixed chuck 2 coincides with the central axis of the movable chuck 3. The translation driver 6 is used to drive the movable chuck 3 to move close to or away from the fixed chuck 2. The rotating driver 4 is arranged on the support 9 and is used to drive the fixed chuck 2 and / or the movable chuck 3 to rotate. The welding mechanism 5 is arranged above the fixed chuck 2 and the movable chuck 3. The welding mechanism 5 comprises a mounting seat and two laser welders arranged in series in front of and behind the mounting seat.

[0029] In actual application, one end of a pipe 10 is clamped by the fixed chuck 2, and the other end of the pipe 10 is clamped by the movable chuck 3. The translation driver 6 drives the movable chuck 3 to move close to the fixed chuck 2 until the two pipes 10 are coaxially butted. Then, the rotating driver 4 drives the fixed chuck 2 and the movable chuck 3 to synchronously rotate at the same rotating direction and the same rotating speed, so that the two coaxially butted pipes 10 synchronously rotate at a constant speed on the support plane formed by the plurality of roller shafts 7. At the same time, the two laser welders arranged in series in front of and behind the mounting seat perform girth welding on the butting position of the two pipes 10. Compared with the traditional TIG welding and single-beam laser welding, the welding quality and efficiency of the present application have obvious advantages. The heat-affected zone width of the TIG welding and the single-beam laser welding is 3-5 mm and 0.5-1.0 mm respectively, and the heat-affected zone width of the double-beam laser welding is reduced to 0.3-0.8 mm. The porosity of the welding seam is reduced to about 2%. Taking aluminum alloy as an example, the joint strength of the welding seam of the double-beam laser welding reaches 88.5% of the base material, and the joint strength of the welding seam of the single-beam laser welding is only 58.3%. The yield rate is improved by 30%. In aerospace, the missile engine shell is welded by double-beam laser welding, and the welding seam meets the aerospace standard without the need for correction. In automobiles, the 2 mm aluminum alloy door beam is welded by double-beam laser welding, which reduces the weight by 30% and has no splashing. In ships, the aluminum alloy deck is welded by double-beam laser welding instead of MIG welding, the heat-affected zone is narrowed by 70%, and the corrosion resistance is improved.

[0030] Preferably, the laser welder can adopt a fiber laser.

[0031] In the embodiment, the power range of the laser welder is 1-30 KW, which is 100 times that of ordinary electric arc welding. The heat-affected zone width is 0.1-1.0 mm. The wavelength of the laser emitted by the laser welder is 1064 nm. The photoelectric efficiency of the laser welder is 30%-40%. The distance between the two laser welders is 0.2-2.0 mm. The structure design effectively improves the welding quality and efficiency.

[0032] In the embodiment, the welding mechanism 5 further comprises a focal length adjusting module arranged on the mounting seat and a spacing adjusting module arranged on the adjusting end of the focal length adjusting module, and the two laser welders are arranged on the two adjusting ends of the spacing adjusting module. The spacing adjusting module is used for adjusting the spacing of the two laser welders, and the focal length adjusting module is used for adjusting the focal length of the laser welder. The structure design makes the focal length and spacing of the two laser welders adjustable, and the power of each laser welder can be independently adjusted to meet the processing requirements of different materials and unequal-thickness pipes of different structures.

[0033] In the embodiment, the welding platform device further comprises a lifting driving mechanism 8 arranged on the base 1, and the two supports 9 are arranged on the lifting ends of the lifting driving mechanism 8. According to the different outer diameters of the unequal-thickness pipes of different specifications, the height of the two supports 9 along with the fixed chuck 2 and the movable chuck 3 is driven by the lifting driving mechanism 8, and the support plane formed by the plurality of rollers 7 can support the pipes 10 of different outer diameters, which is good in versatility.

[0034] In the embodiment, in step D, the unequal-thickness pipe is taken off from the welding platform device by the mechanical arm; the control system analyzes and determines the coordinate position of the unequal-thickness pipe on the welding platform device, calculates the optimal motion trajectory of the mechanical arm according to the coordinate position, so that the mechanical arm moves along the optimal motion trajectory and clamps and discharges the unequal-thickness pipe to the discharging position, which is beneficial to improve the automation degree and improve the production efficiency.

[0035] In the embodiment, after step D, the quality of the unequal-thickness pipe is detected. The mechanical arm first clamps and takes the unequal-thickness pipe to the detection device, the detection device detects the mechanical properties of the unequal-thickness pipe, ensures that the material meets the high-strength requirement of 1.5GPa or above, verifies whether the wall thickness and cross-sectional shape of the unequal-thickness pipe meet the design accuracy through precise measurement technology, detects whether the transition area of the variable cross-section structure is smooth, detects whether there is a welding defect (such as a pore, a crack) or a material loose problem in the unequal-thickness pipe through ultrasonic, X-ray and other technologies, and guarantees the structural integrity; the performance of the unequal-thickness pipe in the collision is evaluated through subsystem simulation analysis (such as side collision, column collision, and top pressure working condition), and it is ensured that the unequal-thickness pipe meets the requirements of bending resistance, energy absorption effect and passenger compartment protection; after the detection is completed, the mechanical arm discharges the detected unequal-thickness pipe to the good product area or the defective product area.

[0036] All the technical features in the embodiment can be freely combined according to actual needs.

[0037] The above embodiment is a preferred implementation scheme of the present application. In addition to this, the present application can also be implemented in other ways, and any obvious replacement without departing from the technical scheme concept is within the protection scope of the present application.

Claims

1. A process for making a variable wall thickness tube, characterized by: The process comprises the following steps: A. Material selection and preparation: select appropriate raw materials according to the performance requirements and application scenarios of the unequal-thickness pipe; after determining the raw materials, inspect and process the raw materials to ensure that the chemical composition and mechanical properties meet the requirements; at the same time, according to the shape and size of the unequal-thickness pipe, the raw materials are cut and pretreated into the required shape and size of the plate; B. Pipe material preparation machine (10): b1. Plate pretreatment: use a leveling machine to eliminate plate rolling residual stress and ensure the flatness of the plate; adjust the pressure value of the leveling machine according to the plate thickness; b2. Roll forming: 3-4 groups of double-curve rollers are set for progressive bending of the plate, and the curvature radius R of the plate is from ∞ to the target value to form a pipe embryo; 2-3 groups of universal rollers are set to close the pipe blank, and the opening angle of the pipe embryo is from 180° to 0° to form a pipe material; b3. Welding: weld the closed mouth of the pipe material; select a suitable welding process according to the material properties, size and application field of the pipe material, and the welding process includes high-frequency resistance welding, TIG welding or laser welding; b4. Sizing and correction: use 3-5 groups of conical rollers to cold roll the pipe material, and control the outer diameter tolerance of the pipe material within the target tolerance range; use a 5-7 roller inclined roller straightening machine to eliminate the bending degree of the pipe material, and the straightness is ≤0.5mm / m; b5. Prepare the pipe material (10) with the required outer diameter and inner diameter size; C. Double-beam laser ring welding: c1. Pipe material (10) loading and fixing: fix two pipe materials (10) with the same outer diameter and different inner diameters prepared in step B on the welding platform device, and fix the two pipe materials (10) with the same outer diameter and different inner diameters with the two clamps of the welding platform device, so that the central axes of the two pipe materials (10) coincide; c2. Laser ring welding process: two laser welders are arranged in series in front and back to form a double-beam laser weld, which is divided into preheating and main welding; the first beam laser welds preheat or cleans the oxide layer of the pipe material (10), and the second beam laser welds deep penetration welding; during welding, the welding platform device drives the two pipe materials (10) with coinciding central axes to rotate continuously and uniformly to realize ring welding of the two pipe materials (10) rotating continuously and uniformly to form an unequal-thickness pipe; D. Unequal-thickness pipe blanking: take the unequal-thickness pipe off the welding platform device.

2. A process for making a variable wall thickness tube as claimed in claim 1, wherein: Before step A, carry out preliminary demand planning: comprehensively consider the application scenarios, performance requirements and preparation feasibility of the unequal-thickness pipe, and determine the performance indicators of the unequal-thickness pipe, including strength, stiffness, impact resistance and lightweight degree.

3. A process for making a variable wall thickness tube as claimed in claim 1, wherein: In step A, the appropriate raw materials include 22MnB5 steel, aluminum alloy and metal composite materials.

4. A process for making a variable wall thickness tube as defined in claim 1 wherein: In step b1, the pressure value of the leveling machine is 50-200KN; in step b4, the target tolerance range of the outer diameter of the pipe material is ±0.1mm.

5. A process for making a variable wall thickness tube as defined in claim 1 wherein: The welding platform device comprises a base (1), a fixed chuck (2), a movable chuck (3), a rotating driver (4), a welding mechanism (5) and a translation driver (6), the bottom surface of the base (1) is rotationally provided with a plurality of roller shafts (7), the plurality of roller shafts (7) form a support plane, the support plane is located between the fixed chuck (2) and the movable chuck (3), two supports (9) are arranged at the two ends of the base (1), the fixed chuck (2) is rotationally connected to one support (9), the translation driver (6) is arranged on the other support (9), the movable chuck (3) is arranged on the translation end of the translation driver (6), the fixed chuck (2) and the movable chuck (3) are oppositely arranged, the central axis of the fixed chuck (2) coincides with the central axis of the movable chuck (3), the translation driver (6) is used for driving the movable chuck (3) to move close to or away from the fixed chuck (2), the rotating driver (4) is arranged on the support (9) and is used for driving the fixed chuck (2) or / and the movable chuck (3) to rotate, the welding mechanism (5) is located above the fixed chuck (2) and the movable chuck (3), and the welding mechanism (5) comprises a mounting seat and two laser welders arranged in series in front and behind the mounting seat.

6. A process for making a variable wall thickness tube as defined in claim 5 wherein: The power range of the laser welder is 1-30KW, the laser wavelength emitted by the laser welder is 1064nm, and the photoelectric efficiency of the laser welder is 30%-40%; the distance between the two laser welders is 0.2-2.0mm.

7. A process for making a variable wall thickness tube as defined in claim 5 wherein: The welding mechanism (5) further comprises a focal length adjusting module arranged on the mounting seat and a distance adjusting module arranged on the adjusting end of the focal length adjusting module, the two laser welders are arranged on the two adjusting ends of the distance adjusting module, the distance adjusting module is used for adjusting the distance between the two laser welders, and the focal length adjusting module is used for adjusting the focal length of the laser welder.

8. A process for making a variable wall thickness tube as defined in claim 5 wherein: The welding platform device further comprises a lifting driving mechanism (8) arranged on the base (1), and the two supports (9) are arranged on the lifting end of the lifting driving mechanism (8).

9. The process of claim 1 wherein: In step D, the unequal-thickness pipe is taken off from the welding platform device by the mechanical arm; the control system analyzes and determines the coordinate position of the unequal-thickness pipe on the welding platform device, calculates the optimal motion trajectory of the mechanical arm according to the coordinate position, so that the mechanical arm moves along the optimal motion trajectory and clamps and discharges the unequal-thickness pipe to the discharging position.

10. A process for making a variable wall thickness tube as defined in claim 9, wherein: After step D, the quality of the unequal-thickness pipe is detected, the mechanical arm first clamps the unequal-thickness pipe into the detection device, the detection device detects the mechanical performance of the unequal-thickness pipe, verifies whether the wall thickness and cross-sectional shape of the unequal-thickness pipe meet the design accuracy, detects whether the transition area of the variable cross-section structure is smooth, detects whether there is a welding defect or material looseness in the unequal-thickness pipe, and simulates and analyzes the performance of the unequal-thickness pipe in the collision; after the detection is completed, the mechanical arm discharges the detected unequal-thickness pipe to the good product area or the defective product area.

Images