Thinning forming method for large cylindrical component with high inner ribs

Abstract

The invention discloses a thinning forming method for a large cylindrical component with high inner ribs. The method comprises the steps that a baffle is installed at the tail end of an inner core shaft, and a drawing outer die is installed on a middle closed type rack; and the cylindrical component with the inner ribs is conveyed to a heating furnace, and the heated cylindrical component with the inner ribs is hoisted and sleeved with the inner core shaft to form a combined structure. A propelling mechanism is connected with the tail end of the inner mandrel, and the head end of the inner mandrel is pushed to penetrate through the outer die ring by stretching a telescopic oil cylinder of the propelling mechanism; a traction mechanism is connected with the head end of the inner mandrel, and a telescopic oil cylinder of the traction mechanism shrinks to drive the combined structure to penetrate through a drawing outer die hole. When the baffle moves to one side of the closed rack in the middle, the traction mechanism and the propelling mechanism stop working, and single-pass thinning deformation of the cylindrical component with the inner rib is completed; and the pushing mechanism telescopic oil cylinder returns to drive the combined structure to exit from the outer mold hole. By means of the method, the thickness of the cylinder wall of the large cylindrical component with the inner rib and the large rib high-wall-thickness-ratio section characteristics can be effectively reduced.

Description

Technical Field

[0001] This invention relates to the field of metal processing technology, and in particular to a method for thinning and forming large cylindrical components with high internal ribs. Background Technology

[0002] Large cylindrical components with internal ribs are typically manufactured using extrusion processes, resulting in rib heights that are close to the cylinder wall thickness. For cylindrical components with a high rib-to-wall-thickness ratio, further wall thinning is required after extrusion to meet final dimensional requirements. Mechanical milling disrupts metal flow lines, reducing the component's mechanical properties and resulting in material waste. Conventional drawing processes such as mandrel drawing are difficult to effectively thin cylindrical components with internal ribs due to the non-uniform circumferential distribution of friction between the component and the inner and outer dies, and cracks or even breakage caused by differences in tensile deformation between the cylinder wall and internal ribs.

[0003] Patent CN118635292A proposes a method for processing cylindrical workpieces using a combination of spinning and cold drawing. The localized loading characteristics of spinning require a high degree of flow and filling ability of the metal material, indicating that it is only suitable for manufacturing plain cylindrical parts and cylindrical parts with short ribs (rib height <30mm). Furthermore, the localized inclusion characteristics of the spinning wheel can easily lead to non-coordinated deformation and stress concentration at geometrically abrupt transition areas such as the rib-wall transition zone, thereby causing micro-cracks and macro-defects.

[0004] Patent CN112588818A discloses a method for rolling and drawing profiles with internal ribs, which is mainly applicable to square cross-section profiles, but the rib filling height is limited. Therefore, it is necessary to propose a thinning forming method for large cylindrical components with high internal ribs to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for thinning and forming large cylindrical components with high internal ribs, so as to solve the problem that the existing technology is difficult to effectively achieve the thinning process of cylindrical components with high internal ribs.

[0006] This invention provides a method for thinning and forming a large cylindrical component with high internal ribs. The method employs a tooling for a combined drawing and extrusion forming of the cylindrical component with internal ribs. This tooling includes a closed frame, a traction mechanism, a propulsion mechanism, a baffle, an inner mandrel, and a drawing die. Three closed frames are arranged in parallel at intervals. The traction mechanism and propulsion mechanism are respectively located on the two side closed frames, and the drawing die is located on the middle closed frame. The traction mechanism and propulsion mechanism are each equipped with a telescopic cylinder. The two ends of the inner mandrel are connected to the telescopic cylinders of the traction mechanism and the propulsion mechanism, respectively. A baffle is installed at the tail end of the inner mandrel. The cross-sectional geometry and dimensions of the inner mandrel are consistent with the internal cross-sectional geometry and dimensions of the cylindrical component with internal ribs to be thinned. The cylindrical component with internal ribs is assembled onto the inner mandrel, with the tail end of the component contacting the baffle. The propulsion mechanism pushes the head end of the inner mandrel into the die hole of the drawing die, and the traction mechanism pulls the inner mandrel and the cylindrical component through the drawing die.

[0007] The method includes the following steps: Step 1: Install the baffle to the end of the inner mandrel and install the drawing outer mold into the middle closed frame.

[0008] Step two: Transport the cylindrical component with internal ribs to the heating furnace, wait for it to be heated to the preset temperature and held for the preset time.

[0009] Step 3: After heating, the inner ribbed cylindrical component is hoisted and fitted into the inner mandrel to form a combined structure; the telescopic cylinder of the propulsion mechanism is connected to the tail end of the inner mandrel, and the first end of the inner mandrel is pushed through the drawing outer mold by extending the telescopic cylinder of the propulsion mechanism.

[0010] Step four: Connect the telescopic cylinder of the traction mechanism to the first end of the inner mandrel. The traction mechanism and the propulsion mechanism start simultaneously. The telescopic cylinder of the traction mechanism retracts, driving the combined structure through the drawing outer mold hole. Under the squeezing action of the inner wall of the drawing outer mold and the outer wall of the inner mandrel, the cylinder wall of the cylindrical component with internal ribs is compressed and thinned. Wait for the baffle to move to one side of the middle closed frame, and the traction mechanism and the propulsion mechanism stop working, completing the single-pass thinning deformation of the cylindrical component with internal ribs.

[0011] Step 5: The telescopic cylinder of the traction mechanism is disconnected from the inner mandrel, and the telescopic cylinder of the propulsion mechanism returns, causing the combined structure to exit the drawing outer mold hole.

[0012] Step 6: Replace the drawing die with a different aperture and repeat steps 1 to 5 to complete the wall thinning of the cylindrical component with internal ribs; after the wall thickness of the cylindrical component with internal ribs is reduced to the target size, disconnect the traction mechanism and the propulsion mechanism from the inner mandrel, remove the combined structure and unload the cylindrical component with internal ribs.

[0013] Furthermore, the inner mandrel, the telescopic cylinder of the traction mechanism, the telescopic cylinder of the propulsion mechanism, and the drawing outer mold are coaxial.

[0014] Furthermore, the inner mandrel surface is machined with grooves that match the geometric shape of the ribs of the cylindrical component with internal ribs.

[0015] Furthermore, the moving speed of the telescopic cylinder is 0.1m / min to 0.6m / min.

[0016] Furthermore, in step two, the preset temperature range is 90℃~400℃, and the preset time is 30min~120min.

[0017] Furthermore, in step four, the traction mechanism and the propulsion mechanism move synchronously, and the moving speed of the traction mechanism is 0.1m / min to 0.6m / min.

[0018] Furthermore, in step six, drawing dies with different apertures are replaced to achieve thinning in each pass; the thinning rate of the first pass is set to 0~5% to shape and correct the wall thickness difference of the cylindrical component; the single-pass thinning rate of the intermediate passes is set to 5%~20% to reduce the wall thickness of the cylindrical component; the thinning rate of the final pass is set to <15% to accurately reduce the wall thickness of the cylindrical component to meet the final dimensional accuracy requirements.

[0019] Furthermore, in step six, the pressure generated by the drawing and extrusion mechanism during the thinning process does not exceed 10 MPa.

[0020] The beneficial effects of this invention are as follows: This invention uses a telescopic hydraulic cylinder in a traction mechanism to pull the combined structure through the outer mold hole. Under the compression of the outer wall of the inner mandrel and the inner wall of the drawing outer mold, as well as the axial constraint of the baffle, the internally ribbed cylindrical component experiences triaxial compressive stress during deformation. This avoids the deformation failure problems caused by surface cracks or even tensile fractures due to the varying stiffness of different parts of the cross-section of the internally ribbed cylindrical component during conventional long-rod drawing processes, where the metal particles in different parts undergo non-uniform flow under uniaxial tensile stress. Simultaneously, the triaxial compressive stress helps eliminate microscopic defects such as porosity and shrinkage cavities in the cylindrical component and achieves a fine-grain strengthening effect. Under conditions of complex cross-sectional characteristics with high ribs and high wall-to-thickness ratios, as well as large diameters, the wall thickness of the internally ribbed cylindrical component is effectively reduced, improving the machining accuracy, yield, and mechanical properties of the cylindrical component. Attached Figure Description

[0021] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort.

[0022] Figure 1This is a schematic diagram of the working state of the present invention. Figure 1 ; Figure 2 It is along Figure 1 Sectional view of AA; Figure 3 This is a schematic diagram of the working state of the present invention. Figure 2 ; Figure 4 This is a schematic diagram of the working state of the present invention. Figure 3 ; Figure 5 This is a schematic diagram of the working state of the present invention. Figure 4 ; Figure 6 This is a front view of the inner mandrel; Figure 7 This is a cross-sectional view of the inner mandrel; Figure 8 It is a cross-sectional view of a cylindrical component with internal reinforcement; Figure 9 This is a schematic diagram of size detection sampling according to an embodiment of the present invention.

[0023] Illustration: 1-Closed frame; 2-Traction mechanism; 3-Propulsion mechanism; 4-Baffle; 5-Cylindrical component with internal ribs; 6-Inner mandrel; 7-Outer drawing die. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. The technical solutions provided by various embodiments of this invention will be described in detail below with reference to the accompanying drawings.

[0025] Please see Figures 1 to 8 This invention provides a method for thinning and forming a large cylindrical component with high internal ribs. The method uses a tooling for drawing and extrusion composite forming of cylindrical components with internal ribs. The tooling includes: a closed frame 1, a traction mechanism 2, a propulsion mechanism 3, a baffle 4, an inner mandrel 6, and a drawing outer die 7.

[0026] Three closed frames 1 are arranged in parallel and fixed to the foundation. A traction mechanism 2 and a propulsion mechanism 3 are respectively mounted on the two closed frames 1 on either side. The drawing die 7 is mounted on the middle closed frame 1. A baffle 4 is installed at the tail end of the inner mandrel 6, and the baffle 4 is used to limit the axial movement of the inner ribbed cylindrical component 5. The traction mechanism 2 and the propulsion mechanism 3 are each equipped with a telescopic hydraulic cylinder. The tail end of the inner mandrel 6 is connected and fixed to the telescopic hydraulic cylinder of the propulsion mechanism 3. The propulsion mechanism 3 is used to push the inner ribbed cylindrical component 5 and one end of the inner mandrel 6 through the die hole of the drawing die 7, facilitating connection with the traction mechanism 2. The telescopic hydraulic cylinder of the traction mechanism 2 is connected to the head end of the inner mandrel 6. The traction mechanism 2, the propulsion mechanism 3, the inner mandrel 6, and the drawing die 7 are coaxial.

[0027] The internal cross-sectional geometry and dimensions of the internally ribbed cylindrical component 5 are consistent with those of the inner mandrel 6. The surface of the inner mandrel 6 is machined with grooves that match the geometric shape of the ribs in the cylindrical component 5. The internally ribbed cylindrical component 5 is assembled onto the inner mandrel 6, forming a combined structure while ensuring that the appearance and geometric dimensions of the ribs remain unchanged. The tail end of the internally ribbed cylindrical component 5 contacts the baffle 4. The pushing mechanism 3 pushes the inner mandrel 6 into the drawing die 7, and the traction mechanism 2 pulls the inner mandrel 6 and the cylindrical component 5 through the drawing die 7. This causes the cylindrical wall of the internally ribbed cylindrical component 5 to undergo plastic deformation under the pressure of the inner wall of the drawing die 7 and the outer wall of the inner mandrel 6, achieving a radial thinning effect.

[0028] The method for thinning and forming a large cylindrical component with high internal ribs includes the following steps: Step 1: Install the baffle 4 to the tail end of the inner mandrel 6, install the drawing outer mold 7 into the middle closed frame 1, and extend the telescopic cylinder of the traction mechanism 2 to one side of the middle closed frame 1.

[0029] Step 2: Transport the inner ribbed cylindrical component 5 to the heating furnace, wait for it to be heated to the preset temperature and held for the preset time.

[0030] Step 3: After heating, the internally ribbed cylindrical component 5 is hoisted and fitted into the inner mandrel 6 to form a combined structure. The baffle 4 is installed at the tail end of the inner mandrel 6. The pushing mechanism 3 is connected to the tail end of the inner mandrel 6, and the telescopic cylinder of the pushing mechanism 3 pushes the head end of the inner mandrel 6 through the drawing outer mold 7.

[0031] Step four: Connect the telescopic cylinder of traction mechanism 2 to the first end of inner mandrel 6. The telescopic cylinder of traction mechanism 2 and the telescopic cylinder of propulsion mechanism 3 are started simultaneously. The telescopic cylinder of traction mechanism 3 retracts, driving the combined structure through the die hole of drawing outer mold 7. Under the squeezing action of the inner wall of drawing outer mold 7 and the outer wall of inner mandrel 6, the wall thickness of the inner ribbed cylindrical component 5 is compressed and thinned. Wait for the baffle 4 to move to one side of the intermediate frame, and traction mechanism 2 and propulsion mechanism 3 stop working, completing the single-pass thinning deformation of inner ribbed cylindrical component 5.

[0032] Step 5: The traction mechanism 2 is disconnected from the inner mandrel 6, and the telescopic cylinder of the propulsion mechanism 3 returns, driving the combined structure to exit the drawing outer mold 7.

[0033] Step six: Replace the drawing die 7 with a different aperture, and repeat steps one through five to complete the wall thickness reduction of the internally ribbed cylindrical component 5. After the wall thickness of the internally ribbed cylindrical component 5 is reduced to the target size, disconnect the traction mechanism and the propulsion mechanism from the inner mandrel, remove the combined structure, and unload the internally ribbed cylindrical component 5.

[0034] The present invention will be described in detail below with reference to specific embodiments. Figure 9 This is a schematic diagram of dimensional inspection sampling according to an embodiment of the present invention, with units in mm. A 7003 aluminum alloy extruded ribbed cylindrical part is used as the object for wall thickness reduction, with an outer diameter of Φ410mm, an inner diameter of Φ400mm, and an internal rib height of 43mm. First, the geometric accuracy, such as roundness and straightness, and surface quality of the incoming cylindrical blank are inspected. The ends are trimmed to ensure a flat and vertical cross-section. Simultaneously, the end faces are chamfered and ground. Then, lubricant is applied to the surfaces of the cylindrical blank, the inner mandrel, and the outer mold. Next, the cylindrical blank is transported to a heating furnace for heating at 100℃-150℃ for 90 minutes. Afterward, the cylindrical blank is hoisted and fitted into the inner mandrel, and thinning and forming are performed according to steps one to six in the specific embodiment. The process is as follows: First pass: Outer die diameter Φ410mm, inner mandrel outer diameter Φ399.9mm; billet outer diameter Φ410mm, inner diameter Φ400mm. After deformation in this pass, the billet outer diameter is Φ410mm, and the inner diameter is Φ399.9mm. This pass is mainly used for billet shaping and wall thickness trimming; the thinning rate in this pass is approximately 0.

[0035] Second pass: Outer die diameter Φ409mm, inner mandrel outer diameter Φ399.9mm; billet outer diameter Φ410mm, inner diameter Φ399.9mm. After this pass, the billet outer diameter is Φ409mm and inner diameter is Φ399.9mm. This pass is used for rough wall reduction (wall reduction of approximately 0.5mm), with a reduction rate of approximately 10%.

[0036] Third pass: Outer die diameter Φ408mm, inner mandrel outer diameter Φ399.9mm; billet outer diameter Φ409mm, inner diameter Φ399.9mm. After this pass, the billet outer diameter is Φ408mm, and the inner diameter is Φ399.9mm. This pass is used for rough wall reduction (wall reduction of approximately 0.5mm), with a reduction rate of approximately 11.1%.

[0037] Fourth pass: Outer die diameter Φ407mm, inner mandrel outer diameter Φ399.9mm; billet outer diameter Φ408mm, inner diameter Φ399.9mm. After this pass, the billet outer diameter is Φ407mm and inner diameter is Φ399.9mm. This pass is used for rough wall reduction (wall reduction of approximately 0.5mm), with a reduction rate of approximately 12.5%.

[0038] Fifth pass: Outer die diameter Φ406mm, inner mandrel outer diameter Φ399.9mm; billet outer diameter Φ407mm, inner diameter Φ399.9mm. After this pass, the billet outer diameter is Φ406mm and inner diameter is Φ399.9mm. This pass is used for rough wall reduction (wall reduction of approximately 0.5mm), with a reduction rate of approximately 14.3%.

[0039] Sixth pass: Outer die diameter Φ405mm, inner mandrel outer diameter Φ399.9mm; billet outer diameter Φ406mm, inner diameter Φ399.9mm. After this pass, the billet outer diameter is Φ405mm and inner diameter is Φ399.9mm. This pass is used for rough wall reduction (wall reduction of approximately 0.5mm), with a reduction rate of approximately 16.7%.

[0040] Seventh pass: Outer die diameter Φ404mm, inner mandrel outer diameter Φ399.9mm; billet outer diameter Φ405mm, inner diameter Φ399.9mm. After this pass, the billet outer diameter is Φ404mm and inner diameter is Φ399.9mm. This pass is used for rough wall reduction (wall reduction of approximately 0.5mm), with a reduction rate of approximately 20%.

[0041] Eighth pass: Outer mold bore diameter Φ403.5mm, inner mandrel outer diameter Φ399.9mm; billet outer diameter Φ404mm, inner diameter Φ399.9mm. After this pass, the cylindrical part dimensions are: outer diameter Φ403.5mm, inner diameter Φ399.9mm. This pass is used for wall reduction and final forming (wall reduction of approximately 0.25mm), with a thinning rate of approximately 12.5%.

[0042] After multiple extrusion and drawing thinning processes, the wall thickness of the ribbed cylindrical component is within the range of 1.7mm-2.0mm. During the thinning process, the traction mechanism speed is controlled at 0.4m / min-0.6m / min, and the pressure generated by the drawing and extrusion mechanism does not exceed 10MPa to avoid the risk of forming failures such as surface scratches and tearing. To reduce the increase in deformation resistance caused by the accumulation of wall reduction, an intermediate annealing treatment at 400℃ is performed after the fifth deformation pass, with a holding time of 15min-25min. Table 1 shows the wall thickness measured at various locations across different cross-sections.

[0043] Table 1. Wall thickness measurement values ​​at different locations on different cross sections As can be seen from the above embodiments, the method for thinning and forming large cylindrical components with high internal ribs involves using a traction mechanism and a telescopic cylinder to pull the combined structure through the outer mold hole. The stress state of the cylindrical component with internal ribs in the gap between the outer wall of the inner mandrel and the inner wall of the outer mold is triaxial compressive stress. The rib section is constrained by the groove of the inner mandrel and deforms only along the axial direction. Under the action of triaxial compressive stress, the cylinder wall section flows simultaneously along the axial and radial directions, thereby achieving the effect of reducing the cross-sectional size. At the same time, this avoids deformation defects such as pull-out cracks caused by different axial tensile stresses on different parts of the cross-section of the cylindrical component with internal ribs during conventional long mandrel drawing. In addition, the compressive stress eliminates microscopic defects such as porosity and shrinkage cavities in the cylinder and achieves a fine grain strengthening effect. Under the condition that the component has complex cross-sectional characteristics with high ribs and high wall thickness ratio and large diameter, the wall thickness of the cylindrical component with internal ribs is effectively reduced, improving the processing accuracy, yield, and mechanical properties of the cylindrical component with internal ribs.

[0044] This solution can effectively reduce the wall thickness of large cylindrical components with high internal ribs (outer diameter 410mm, internal rib height 43mm). Compared with conventional drawing or spinning methods, this solution can reduce the wall thickness while maintaining the geometric dimensions and accuracy of the ribs, and the resulting cylindrical component has fewer deformation defects.

[0045] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0046] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented, for example, in sequences other than those illustrated or described herein.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for thinning and forming a large cylindrical component with high internal ribs, characterized in that, The method employs a tooling for combined drawing and extrusion forming of cylindrical components with internal ribs, the tooling comprising: The closed frame (1), traction mechanism (2), propulsion mechanism (3), baffle (4), inner mandrel (6), and drawing outer mold (7) are arranged in parallel intervals. The traction mechanism (2) and the propulsion mechanism (3) are respectively arranged on the closed frames (1) on both sides, and the drawing outer mold (7) is arranged on the closed frame (1) in the middle. The traction mechanism (2) and the propulsion mechanism (3) are respectively equipped with telescopic cylinders. The two ends of the inner mandrel (6) are respectively connected to the telescopic cylinder of the traction mechanism (2) and the propulsion mechanism (3). The telescopic cylinder is connected; the baffle (4) is installed at the tail end of the inner mandrel (6); the cross-sectional geometry and size of the inner mandrel (6) are consistent with the internal cross-sectional geometry and size of the inner ribbed cylindrical component (5) to be thinned; the inner ribbed cylindrical component (5) is assembled to the inner mandrel (6), and the tail end of the inner ribbed cylindrical component (5) contacts the baffle (4); the pushing mechanism (3) is used to push the head end of the inner mandrel (6) into the die hole of the drawing outer die (7), and the traction mechanism (2) is used to pull the inner mandrel (6) and the cylindrical component (5) through the drawing outer die (7); The method includes the following steps: Step 1: Install the baffle (4) to the tail end of the inner mandrel (6) and install the drawing outer mold (7) into the middle closed frame (1); Step 2: Transport the cylindrical component (5) with internal ribs to the heating furnace, wait for it to be heated to the preset temperature and held for the preset time; Step 3: After heating, the inner ribbed cylindrical component (5) is hoisted and fitted into the inner mandrel (6) to form a combined structure; the telescopic cylinder of the propulsion mechanism (3) is connected to the tail end of the inner mandrel (6), and the head end of the inner mandrel (6) is pushed through the drawing outer mold (7) by extending the telescopic cylinder of the propulsion mechanism (3). Step 4: Connect the telescopic cylinder of the traction mechanism (2) to the first end of the inner mandrel (6). The traction mechanism (2) and the propulsion mechanism (3) start simultaneously. The telescopic cylinder of the traction mechanism (2) retracts and drives the combined structure through the drawing outer mold (7) die hole. Under the squeezing action of the inner wall of the drawing outer mold (7) and the outer wall of the inner mandrel (6), the cylinder wall of the inner ribbed cylindrical component (5) is compressed and thinned. Wait for the baffle (4) to move to one side of the middle closed frame (1). The traction mechanism (2) and the propulsion mechanism (3) stop working, and the single-pass thinning deformation of the inner ribbed cylindrical component (5) is completed. Step 5: The telescopic cylinder of the traction mechanism (2) is disconnected from the inner mandrel (6), and the telescopic cylinder of the propulsion mechanism (3) returns to drive the combined structure out of the drawing outer mold (7) mold hole; Step 6: Replace the drawing die (7) with a different aperture and repeat steps 1 to 5 to complete the thinning of the cylindrical wall of the inner ribbed cylindrical component (5). After the cylindrical wall thickness of the inner ribbed cylindrical component (5) is reduced to the target size, disconnect the traction mechanism (2) and the propulsion mechanism (3) from the inner mandrel (6), remove the combined structure and unload the inner ribbed cylindrical component (5).

2. The method for thinning and forming a large cylindrical component with high internal ribs according to claim 1, characterized in that, The inner mandrel (6), the telescopic cylinder of the traction mechanism (2), the telescopic cylinder of the propulsion mechanism (3), and the drawing outer mold (7) are coaxial.

3. The method for thinning and forming a large cylindrical component with high internal ribs according to claim 1, characterized in that, The inner mandrel (6) has grooves on its surface that are consistent with the geometric shape of the ribs of the inner ribbed cylindrical component (5).

4. The method for thinning and forming a large cylindrical component with high internal ribs according to claim 1, characterized in that, The telescopic cylinder has a moving speed of 0.1 m / min to 0.6 m / min.

5. The method for thinning and forming a large cylindrical component with high internal ribs according to claim 1, characterized in that, In step two, the preset temperature range is 90℃~400℃, and the preset time is 30min~120min.

6. The method for thinning and forming a large cylindrical component with high internal ribs according to claim 1, characterized in that, In step four, the traction mechanism (2) and the propulsion mechanism (3) move synchronously, and the moving speed of the traction mechanism (2) is 0.1m / min to 0.6m / min.

7. The method for thinning and forming a large cylindrical component with high internal ribs according to claim 1, characterized in that, In step six, the drawing die (7) with different apertures is replaced to achieve thinning in one pass; the thinning rate of the first pass is set to 0~5% for shaping and correcting the wall thickness difference of the cylinder. The single-pass thinning rate of intermediate passes is set at 5% to 20% to reduce the wall thickness of cylindrical components; the pass thinning rate of the final pass is set at <15% to precisely reduce the wall thickness of cylindrical components to meet the final dimensional accuracy requirements.

8. The method for thinning and forming a large cylindrical component with high internal ribs according to claim 1, characterized in that, In step six, the pressure generated by the drawing and extrusion mechanism during the thinning and forming process shall not exceed 10 MPa.

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