A spinning forming method for a 5A06 aluminum alloy thin-wall special-shaped cylinder

Abstract

The application discloses a spinning forming method for a 5A06 aluminum alloy thin-wall special-shaped cylinder body, belongs to the technical field of precise plastic forming, and aims to solve the problems of poor workpiece size precision, low production efficiency, and too many welds affecting strength of existing thin-wall special-shaped cylinder body plate rolling and welding forming technology. The application adopts a process of "plate material-heat spinning preforming-machining-multi-pass power spinning forming" to form the workpiece, adopts an equal-wall-thickness plate material, adopts multiple spinning processes to form the workpiece, adopts heat spinning forming in the first spinning process, and adopts power spinning forming processes in the second spinning process to the last spinning process. The machining process is performed after the first-pass heat spinning is completed, and annealing heat treatment is performed after each pass is completed.

Description

Summary of the Invention

[0001] For 5A06 aluminum alloy thin-walled irregular cylindrical bodies that have both straight cylindrical sections and curved generatrix cylindrical sections, a forming method of "sheet composite spinning + heat treatment" is adopted. Specifically, sheet hot spinning is first used, followed by machining and two room temperature high-pressure spinning processes. An annealing process is matched during the spinning process to finally achieve the overall forming of the 5A06 aluminum alloy thin-walled irregular cylindrical body.

[0002] The technical solution adopted in this invention includes the following steps:

[0003] Step 1: Design the overall forming process of the long straight section curved cylinder, which includes three spinning passes, each pass consisting of several ordinary spinning and compound spinning passes;

[0004] Step 2: Select a 22mm thick aluminum alloy round sheet as the spinning blank;

[0005] Step 3: Calculate the spinning path and mold outer surface shape for each pass, and determine the machining process after each pass of spinning;

[0006] Step 4: Mount the blank selected in Step 2 and the hot swirl die determined in Step 3 onto the spinning machine;

[0007] Step 5: Based on the spinning route determined in Step 3, perform one hot spinning pass at a spinning temperature of 340℃.

[0008] Step 6: Perform annealing heat treatment at 320℃ for 2 hours on the blank obtained in Step 5.

[0009] Step 7: Perform machining on the heat-treated blank obtained in Step 6 to remove the oxide scale on the surface after one hot spinning pass, and ensure that the wall thickness at each location meets the theoretical requirements for the thickness of the subsequent two shearing and spinning passes.

[0010] Step 8: Perform the subsequent second and third spinning processes based on the calculations in Step 3.

[0011] Step 9: Perform annealing heat treatment at 320℃ for 2 hours on the final workpiece, and machine the large and small ends to cut to size, completing the overall spinning process of the front curved cylinder.

[0012] Advantages and excellent effects of the present invention: The present invention explores a spinning processing method to replace the current process of "roll welding + machining + segmented welding", which improves material utilization by 50%, processing efficiency by 100%, and mechanical properties by 10%, and can realize the integral forming of straight cylinder sections and curved busbar cylinder sections. Attached Figure Description

[0013] Figure 1It is a multi-pass spinning process, including: 101, spinning blank, 102, blank after the first pass, 103, blank after machining after the first pass, 104, blank after the second pass, and 105, final formed part after the third pass. Figure 2 It is a series of spinning processes and the trajectory of each spinning wheel, where 201 is the first spinning stroke of the first series, 202 is the second spinning stroke of the first series, 203 is the third spinning stroke of the first series, 204 is the fourth spinning stroke of the first series, 205 is the fifth spinning stroke of the first series, and 206 is the sixth spinning stroke of the first series. Figure 3 This describes the three-pass spinning process and the names and locations of the components involved, including: 1. Tail ejector rod, 2. Tail ejector block, 3. Spinning blank, and 4. Core mold. Figure 4 It refers to the final spinning process and the names of the corresponding blank positions and components during the spinning process, including 5, blank curved cylinder part, 6, blank straight cylinder part, 7, R spinning wheel, and 8, double conical spinning wheel. Detailed Implementation

[0014] The embodiments of the present invention will be further described below with reference to the accompanying drawings.

[0015] See Figure 1 The spinning process for thin-walled, irregularly shaped aluminum alloy cylinders includes the following steps:

[0016] Step 1: Design the integral forming process of aluminum alloy thin-walled irregular cylinder, which includes one hot spinning pass, intermediate machining, two and three room temperature high-strength spinning passes, annealing and final machining.

[0017] Step Two: Calculate the spinning path, die outer surface shape, and blank shape for each spinning pass to determine the machining process between spinning passes: Using the wall thickness and shape of the three-pass part as the target, and based on the shear spinning sinusoidal law, while maintaining the maximum thinning rate of 5A06 aluminum alloy, reverse-engineer the inner and outer surfaces of the blanks for the second and third spinning passes with equal wall thickness. Based on the reverse-engineered shapes of the second and third passes, determine the shape of the blank after machining for the first pass, and reserve machining allowances for the inner and outer surfaces, determining the inner and outer surface profiles of the blank for the first pass. A single hot-spinning pass will shape the sheet metal as shown in Figure 102 to meet the machining requirements after spinning. To improve the die fit in each pass and enhance the final forming accuracy, a 5-10% negative deviation rate is reserved for the wall thickness of each spinning pass.

[0018] Step 3: Select a 22mm thick circular sheet of 5A06 aluminum alloy as the spinning blank. Based on the maximum radius of the beveled edge and the volume of the straight edge determined in Step 2, determine the radius of the circular sheet.

[0019] Step 4: Adjust the spinning machine, install the R24 spinning wheel, clamp the round sheet blank selected in Step 3 and the first-pass mold determined in Step 2 onto the spinning machine, preheat it to 340℃ using a propane spray gun, and spin according to the spinning route determined in Step 2. During the process, the spray gun provides additional heat to the spinning position. After spinning is completed, unload the material and air cool it.

[0020] Step 5: Clean the surface of the blank obtained in Step 4 to remove dust and oil, then perform vacuum annealing heat treatment at 320℃ for 2 hours. The heating time is 2 hours, and after reaching the temperature, it is held at that temperature for 2 hours, then removed from the furnace and air-cooled.

[0021] Step Six: Perform turning machining on the heat-treated blank obtained in Step Five to remove the oxide scale on the surface after one hot spinning pass. After machining, the wall thickness of the blank at various points meets the theoretical requirements for the thickness of the subsequent second and third shearing and spinning passes.

[0022] Step 7: Based on the spinning path and die calculated in Step 2, perform the subsequent second and third spinning processes. The radius of the spinning wheel for the curved cylindrical section is R20, and three wheels are used for synchronous spinning; the straight section uses a double-conical wheel with three wheels staggered for spinning.

[0023] Step 9: Perform vacuum annealing heat treatment on the final workpiece at 320℃ for 2 hours. After annealing, cut the large and small ends to the target size to complete the overall spinning process of the aluminum alloy thin-walled irregular cylinder.

[0024] The specific spinning paths and mold outer surface shapes for each pass described in step two are as follows:

[0025] 1) One time

[0026] The shape and spinning path of the secondary hot spun die are shown below. Figure 2 Among them, 201, 202, 203, 204, 205, and 206 are spinning routes. The straight section of the billet is formed into the straight section of the subsequent passes, and the curved section is formed into the curved section of the subsequent passes.

[0027] 2) Second pass

[0028] The second spinning path and die shape are shown below. Figure 3 The overall spinning route is determined as follows: first, the curved generatrix section is shaped by three synchronous spinning wheels using R-type spinning wheels, and then the straight section is shaped by three staggered spinning wheels using double-conical spinning wheels.

[0029] 3) Three rounds

[0030] The three-pass spinning path is shown below. Figure 4 The second-pass blanks are annealed and machined, and then the thickness direction meets the requirements of the third-pass spinning method, which is the same as the second-pass spinning method.

[0031] In this embodiment, taking one pass as an example: the blank 3 is clamped onto the core mold 4 via the tail ejector rod 1 and tail ejector block 2, with a spinning wheel radius (R) of 24mm. The blank is preheated using a propane spray gun to 340℃, and then fed along the spinning path at the spinning wheel radius (R) position for processing. The blank completes hot spinning under the constraints of the spinning wheel radius (R) and the mold's outer surface. After spinning, the blank is unloaded and air-cooled to room temperature.

[0032] During the overall spinning process, the spindle speed is 50-100 rpm and the spinning wheel feed speed is 60-120 mm / min.

Claims

1. A method for spinning a thin-walled irregular cylindrical body made of 5A06 aluminum alloy, characterized in that, Includes the following steps: Step 1: Design the overall forming process of the long straight section curved cylinder, which includes three spinning passes, each pass consisting of several ordinary spinning and compound spinning passes; Step 2: Select a 22mm thick aluminum alloy round sheet as the spinning blank; Step 3: Calculate the spinning path and mold outer surface shape for each pass, and determine the machining process after each pass of spinning; Step 4: Clamp and fix the spinning blank selected in Step 2 and the corresponding mandrel determined in Step 3 on the spinning machine; Step 5: Perform one hot spin according to the spinning route determined in Step 4, with a spinning temperature of 340℃.

2. Step Six: Perform annealing heat treatment at 320℃ for 2 hours on the blank obtained in Step Five.

3. Step 7: Perform machining on the heat-treated blank obtained in Step 6 to remove the oxide scale on the surface after one hot spinning pass, and ensure that the wall thickness at each location meets the theoretical requirements for the thickness of the subsequent two shearing and spinning passes.

4. Step 8: Perform the subsequent second and third spinning forming based on the calculations in Step 3.

5. Step Nine: Perform annealing heat treatment at 320℃ for 2 hours on the final workpiece, and machine the large and small ends to cut to size, completing the overall spinning process of the front curved cylinder.

6. The spinning forming method for a thin-walled irregular cylindrical body of 5A06 aluminum alloy according to claim 1, characterized in that, The starting point of the first pass of hot spinning in step one is at the part where the thickness of the circular blank is less than the theoretical thickness requirement of shear spinning. The total number of spinning passes is m, and the value of m is in the range of 5≤m≤7. This ensures that the thickness of the spun blank after spinning is greater than the theoretical thickness of shear spinning at the corresponding position.

7. The spinning forming method for a thin-walled irregular cylindrical body of 5A06 aluminum alloy according to claim 1, characterized in that, The machining process between the first and second passes described in step three removes the oxide scale and machining allowance from the surface after the first rotary pass, achieving the thickness theoretically required for shearing the curved generatrix area in the latter two passes.

8. The spinning forming method for a thin-walled irregular cylindrical body of 5A06 aluminum alloy according to claim 1, characterized in that, In the aforementioned spinning forming method, the workpiece is annealed after each pass.

9. A spinning forming method for a thin-walled irregular cylindrical body of 5A06 aluminum alloy according to any one of claims 1, characterized in that, In step four, a round hole is used to position the hot spinning mold and the blank. The diameter of the round hole ranges from 20 to 40 mm.

10. A spinning forming method for a thin-walled irregular cylindrical body of 5A06 aluminum alloy according to any one of claims 1, characterized in that, In the spinning process described in step five, after the blank is preheated in the resistance furnace, a propane spray gun is used to keep it warm during the spinning process, and the holding temperature is 340-380℃.

11. A spinning forming method for a thin-walled irregular cylindrical body of 5A06 aluminum alloy according to any one of claims 1, characterized in that, The annealing process described in step six involves holding at 320℃ for 2 hours followed by furnace cooling. The heat treatment equipment is a trolley-type resistance furnace.

12. A spinning forming method for a thin-walled irregular cylindrical body of 5A06 aluminum alloy according to any one of claims 1, characterized in that, The machining steps described in step seven are performed between the first and second spinning passes. After machining, the curved generatrix portion becomes a cylinder with equal wall thickness. The thickness and curvature meet the requirements for the final spinning part to be sheared and spun. The positioning holes of the blank and the first-pass mold are enlarged and machined to meet the positioning requirements.

13. A spinning forming method for a 5A06 aluminum alloy thin-walled irregular cylindrical body according to any one of claims 1, characterized in that, Step eight describes the second and third spinning passes using a three-wheel horizontal spinning machine, with different spinning wheels used for the curved and straight cylinders. The curved cylinder is spun synchronously using an R-wheel, with a spindle speed of 40-80 rpm and a feed rate of 0.5-1 mm / s; the straight cylinder is spun using a double-conical spinning wheel with staggered spacing, a spindle speed of 80-120 rpm and a feed rate of 1-1.2 mm / s.

14. A spinning forming method for a thin-walled irregular cylindrical body of 5A06 aluminum alloy according to any one of claims 1, characterized in that, The second and third spinning and annealing heat treatments described in steps eight and nine are performed using a trolley-type resistance furnace, with the process involving holding at 320℃ for 2 hours followed by furnace cooling.

15. A spinning forming method for a thin-walled irregular cylindrical body of 5A06 aluminum alloy according to any one of claims 1, characterized in that, The final machining described in step nine involves using a lathe or a large vertical milling machine for cutting. During machining, the inside of the cylinder is supported by a nylon liner, and the outside is fixed using a circular alignment fixture.

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