VW93M magnesium alloy inclined wall cylindrical forging and method of manufacture

Abstract

This invention provides a method for manufacturing VW93M magnesium alloy inclined-wall cylindrical forgings that have excellent overall mechanical properties and are suitable for the manufacture of missile cabins. [Solution] A VW93M magnesium alloy ingot is subjected to stepwise homogenization annealing, the resulting homogenized ingot is upset and drawn into ingots, the resulting upset and drawn forged material is sequentially upset and cylindrical forging, the resulting cylindrical forged material is die forged, and then T5 heat treatment is performed to obtain a VW93M magnesium alloy inclined wall cylindrical forging. Based on the high-strength, heat-resistant VW93M magnesium alloy, which has a lower density than aluminum alloy, this invention employs a composite forming process of upset and drawn into ingots + cylindrical forging + die forging to successfully manufacture a VW93M magnesium alloy inclined wall cylindrical forging with excellent overall mechanical properties, making it suitable for the manufacture of missile cabins.

Description

【Technical Field】 【0001】 The present invention relates to the technical field of magnesium alloy deformation processing, and particularly to a VW93M magnesium alloy inclined wall cylindrical forging and a manufacturing method thereof. 【Background Art】 【0002】 In order to reduce the resistance during flight, the missile casing is usually designed with an outer shape having a certain taper. Therefore, the cabin part in the central part of the missile is usually required to be manufactured into an inclined wall cylindrical member. Due to the connection between the cabin parts, a large end frame or flange ring structure for bolt connection needs to be designed at one end of the cabin. Currently, this type of inclined wall cylindrical cabin cannot be manufactured using the ring rolling process. Therefore, this cabin is usually manufactured by riveting an aluminum truss and an aluminum outer plate. The flange ring (end frame) is usually manufactured by cutting an aluminum plate. Both are usually connected by bolts. The missile cabin manufactured in this way uses a large amount of aluminum materials and steel (titanium, aluminum) rivets (bolts), the assembly process is complicated, and the total mass of the cabin is large. 【0003】 Magnesium alloy is the lightest metal structural material currently applicable industrially. Patent Document 1 discloses a manufacturing method of a VW93M magnesium alloy medium-thick plate. Specifically, a VW93M magnesium alloy medium-thick plate is manufactured using multiple high-speed multi-directional free forging processes. This VW93M magnesium alloy medium-thick plate has high strength and good plasticity. The shape of the forging has an important influence on the selection of the forming process, the formulation of the process route, and the mechanical properties. How to manufacture an inclined wall cylindrical forging with excellent comprehensive mechanical properties is a technical problem that needs to be solved urgently at present. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 China patent CN117259635B [Overview of the project] [Problems that the invention aims to solve] 【0005】 The object of the present invention is to provide a VW93M magnesium alloy inclined wall cylindrical forging, a method for manufacturing it, and its use. The density of the VW93M magnesium alloy of the present invention is lower than that of aluminum alloy, and the VW93M magnesium alloy inclined wall cylindrical forging has excellent overall mechanical properties and is suitable for the manufacture of missile cabins. [Means for solving the problem] 【0006】 To achieve the objectives of the above invention, the present invention provides the following technical solutions. 【0007】 The present invention provides a method for manufacturing a VW93M magnesium alloy inclined wall cylindrical forging, comprising the steps of: obtaining a homogenized ingot by performing stepwise homogenization annealing on a VW93M magnesium alloy ingot; obtaining an upset and draw forging material by performing upset and draw division on the homogenized ingot, wherein the number of upset and draw divisions is 1 to 2, and each upset and draw division includes sequential upsetting, drawing, and heat retention treatments, wherein the reduction amount in the main deformation direction during the upsetting treatment in each upset and draw division is 30% or more, and the forging press speed for each upset and draw division is independently 1 to 10 mm / s; and upsetting treatment on the upset and draw forging material. The process includes the steps of: sequentially performing shaping and cylindrical forging to obtain a cylindrical forged material, performing upsetting on the upset and drawn forged material with a reduction in the main deformation direction of 30% or more, a forging press speed of 1 to 10 mm / s, and the cylindrical forging process including multiple cylindrical forging processes performed in the radial direction, with the deformation amount of each cylindrical forging process not exceeding 8%; performing die forging on the cylindrical forged material to obtain a formed forged product, with a press speed of 0.1 to 6 mm / s for the die forging; and performing T5 heat treatment on the formed forged product to obtain the VW93M magnesium alloy inclined wall cylindrical forged product. 【0008】 Preferably, the diameter of the VW93M magnesium alloy ingot is 400 to 550 mm, and the stepwise homogenization annealing includes sequentially performing a first annealing and a second annealing, wherein the temperature of the first annealing is 400 to 440°C, the holding time for the first annealing is 5 to 8 hours, the temperature of the second annealing is 500 to 540°C, and the holding time for the second annealing is 20 to 25 hours. 【0009】 Preferably, the process further includes separating the homogenized ingot before the upsetting and drawing process to obtain cast rods with a diameter of 400-500 mm and a length of 800-1250 mm. 【0010】 Preferably, a first heat treatment is further included between the separation and the upsetting and drawing of the mass, wherein the temperature of the first heat treatment is 420 to 530°C and the holding time of the first heat treatment is 7 to 11 hours. 【0011】 Preferably, the upsetting process for each upset-drawn mass involves one forging press to achieve the target height, the drawing process involves 8 to 12 forging presses to achieve the target height, the temperature of the heat retention process for each upset-drawn mass is independently 420 to 500°C, and the duration of the heat retention process for each upset-drawn mass is independently 2 to 3 hours. 【0012】 Preferably, the upsetting process is performed on the upset-drawn forged material, involving one forging press to achieve the target height, and the number of cylindrical forging processes does not exceed eight. 【0013】 Preferably, the process further includes performing a second heat treatment on the cylindrical forging material before the die forging, wherein the second heat treatment is performed at a temperature of 420-500°C and holds for 7-11 hours. 【0014】 Preferably, the T5 heat treatment is performed at a temperature of 200-250°C and with a holding time of 14-24 hours. 【0015】 The present invention provides a VW93M magnesium alloy inclined wall cylindrical forging manufactured by the manufacturing method described above. 【0016】 The present invention provides for the use of the VW93M magnesium alloy inclined wall cylindrical forging described in the above technical solution in the manufacture of a missile cabin. [Effects of the Invention] 【0017】 The beneficial effects of the present invention are as follows. Based on the high-strength and tough VW93M magnesium alloy in a wide temperature range, the present invention adopts a composite forming process of installation extraction and block division + cylindrical forging shaping + die forging shaping to successfully manufacture a VW93M magnesium alloy inclined wall cylindrical forging. Among them, the density of the VW93M magnesium alloy is smaller than that of the aluminum alloy, and the VW93M magnesium alloy inclined wall cylindrical forging has excellent comprehensive mechanical properties and is suitable for the manufacture of missile cabins. 【Brief Description of the Drawings】 【0018】 [Figure 1] It is a physical diagram of a magnesium alloy ingot with a diameter of 460 mm obtained after semi-continuous casting in Example 1 of the present invention. [Figure 2] It is a physical diagram of a cylindrical forged material obtained after cylindrical forging shaping in Example 1 of the present invention. [Figure 3] It is a physical diagram of a VW93M magnesium alloy inclined wall cylindrical forging manufactured in Example 1 of the present invention. [Figure 4] It is a characteristic evaluation diagram of the low-magnification metal structure of the VW93M magnesium alloy inclined wall cylindrical forging manufactured in Example 1. [Figure 5] It is a characteristic evaluation diagram of the high-magnification electron backscatter diffraction (EBSD) of the VW93M magnesium alloy inclined wall cylindrical forging manufactured in Example 1. . [Figure 6] It is a morphological diagram of the tensile fracture surface of the VW93M magnesium alloy inclined wall cylindrical forging manufactured in Example 1. 【Modes for Carrying Out the Invention】 【0019】 The present invention provides a method for manufacturing a VW93M magnesium alloy inclined wall cylindrical forging. Steps include: performing stepwise homogenization annealing on a VW93M magnesium alloy ingot to obtain a homogenized ingot; performing upsetting and drawing on the homogenized ingot to obtain an upsetting and drawing forged material, wherein the number of upsetting and drawing steps is 1 to 2, and each upsetting and drawing step includes sequential upsetting, drawing, and heat retention treatments, the reduction amount in the main deformation direction of the upsetting step in each upsetting and drawing step is 30% or more, and the forging press speed for each upsetting and drawing step is independently 1 to 10 mm / s; and upsetting the upsetting and drawing forged material The process includes the steps of: sequentially performing processing and cylindrical forging to obtain a cylindrical forged material, performing upsetting on the upset-drawn forged material with a reduction amount of 30% or more in the main deformation direction, a forging press speed of 1 to 10 mm / s, and the cylindrical forging process including multiple cylindrical forging processes performed in the radial direction, with the deformation amount of each cylindrical forging process not exceeding 8%; performing die forging on the cylindrical forged material to obtain a formed forged product, with a press speed of 0.1 to 6 mm / s for the die forging; and performing T5 heat treatment on the formed forged product to obtain a VW93M magnesium alloy inclined wall cylindrical forged product. 【0020】 At present, in the related art, the cabin part in the central part of the missile is usually required to be manufactured into an inclined wall cylindrical member. A large amount of aluminum alloy is used in the manufacture of the missile cabin, and a large amount of rivets (bolts) made of steel (titanium, aluminum) are used. The assembly process is complicated and the total mass of the cabin is large. The Mg-Gd-Y-Zr series alloy is superior to the aluminum alloy in terms of comprehensive mechanical properties such as high-temperature mechanical properties and low-temperature mechanical properties, and its density is about 1 / 3 lower than that of the aluminum alloy. Since the diameter and depth of the inclined wall cylindrical member are large and the cylinder wall has a certain taper, it is difficult to manufacture an inclined wall cylindrical forging using the forging process, and the manufacturing difficulty of large free forging materials of high-quality high rare earth magnesium alloy is also large. At present, there is no relevant research and successful example of the manufacturing process of high-strength magnesium alloy inclined wall cylindrical forgings. The present invention is based on the high-strength heat-resistant VW93M magnesium alloy, adopts a composite forming process of installation extraction block + cylindrical forging shaping + die forging forming, and successfully manufactures a VW93M magnesium alloy inclined wall cylindrical forging with excellent comprehensive mechanical properties, which is suitable for the manufacture of missile cabins. Hereinafter, the method of the present invention will be described in detail. 【0021】 This invention provides a method for obtaining a homogenized ingot by performing stepwise homogenization annealing on a VW93M magnesium alloy ingot. As one embodiment of the present invention, the diameter (Φ) of the VW93M magnesium alloy ingot may be 400 to 550 mm, and moreover, 440 to 480 mm, specifically 440 mm, 450 mm, 460 mm, 470 mm, or 480 mm, and the composition of the VW93M magnesium alloy ingot may include, by mass percentage, Gd 8.0 to 9.6%, Y 1.8 to 3.2%, Zr 0.3 to 0.7%, Ag 0.02 to 0.5%, Er 0.02 to 0.3%, with the remainder being Mg and unavoidable impurities, and Gd 8.8 to 9.2%, Y 2.0 to 2.6%, Zr 0.4 to 0.5%, Ag 0.1 to 0.3%, Er It may further contain 0.2-0.3%, with the remainder being Mg and unavoidable impurities, specifically, Gd 8.98%, Y 2.33%, Zr 0.44%, Ag 0.24%, Er 0.28%, with the remainder being Mg and unavoidable impurities. In one embodiment of the present invention, the VW93M magnesium alloy ingot may be manufactured by a semi-continuous casting method, and the present invention does not particularly limit the specific operating steps and conditions of the semi-continuous casting method, but rather uses operating steps and conditions that are familiar to those skilled in the art. In the embodiment of the present invention, a high-quality VW93M magnesium alloy ingot can be manufactured using a semi-continuous casting method, and defects such as inclusions, pores, porosity, and core cracks can be reduced, and by controlling the number of defects, the tendency to crack in subsequent deformation processes can be reduced, and the formability of the magnesium alloy in subsequent forging and die forging deformation processes can be improved. 【0022】 As one embodiment of the present invention, the stepwise homogenization annealing may include sequentially performing a first annealing and a second annealing, the temperature of the first annealing may be 400 to 440°C, specifically 400°C, 410°C, 420°C, 430°C, or 440°C, the holding time may be 5 to 8 hours, specifically 5 hours, 6 hours, 7 hours, or 8 hours, the temperature of the second annealing may be 500 to 540°C, specifically 500°C, 510°C, 520°C, 530°C, or 540°C, and the holding time may be 20 to 25 hours, specifically 20 hours, 21 hours, 22 hours, 23 hours, 24 hours, or 25 hours. In the embodiments of the present invention, the VW93M magnesium alloy ingot can be heated together with the furnace to the temperature for the first annealing, maintained at that temperature for the first annealing, then heated to the temperature for the second annealing, maintained at that temperature for the second annealing, and finally air-cooled to room temperature. In the embodiments of the present invention, the purpose of employing stepwise homogenization annealing is to ensure that the large ingot is heated steadily during the homogenization process, to avoid cracking due to rapid temperature changes, to make the structural components uniform, to improve plasticity, and to reduce deformation resistance. 【0023】 After obtaining a homogenized ingot, the present invention performs upsetting and drawing on the homogenized ingot to obtain an upsetting and drawing forged material. In one embodiment of the present invention, before the upsetting and drawing, the homogenized ingot may be further separated to obtain a cast rod having a diameter of 400 to 500 mm and a length of 800 to 1350 mm, wherein the diameter of the cast rod may be further 400 to 430 mm, specifically 400 mm, 410 mm, 420 mm, or 430 mm, and the length may be further 900 to 1250 mm, specifically 900 mm, 950 mm, 1000 mm, 1050 mm, 1100 mm, 1150 mm, 1200 mm, or 1250 mm. As one embodiment of the present invention, the invention may further include sequentially performing mechanical turning and flaw detection before the separation, and the present invention does not particularly limit the specific operating steps and conditions of the mechanical turning and flaw detection, and operating steps and conditions familiar to those skilled in the art may be adopted. 【0024】 As one embodiment of the present invention, a first heat treatment may be further included between the separation and the upsetting and drawing of the mass, the temperature of the first heat treatment may be 420 to 530°C, specifically 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, 500°C, 510°C, 520°C, or 530°C, and the holding time may be 7 to 11 hours, specifically 7 hours, 8 hours, 9 hours, 10 hours, or 11 hours. 【0025】 In the present invention, the number of upsetting and drawing operations may be 1 to 2, and each upsetting and drawing operation includes sequential upsetting, drawing, and heat retention treatments, and the reduction amount in the main deformation direction (i.e., axial direction) of the upsetting operation in each upsetting and drawing operation is 30% or more, for example, 30 to 50%, specifically 30%, 35%, 40%, 45%, or 50%, and the forging press speed for each upsetting and drawing operation is independently 1 to 10 mm / s, and further may be 1 to 5 mm / s, specifically 1 mm / s, 2 mm / s, 3 mm / s, 4 mm / s, or 5 mm / s. 【0026】 In one embodiment of the present invention, the upsetting process for each upsetting and drawing block may consist of one forging press to achieve the target height, and the drawing process may consist of 8 to 12 forging presses, specifically 5, 6, 7, 8, 9, 10, 11, or 12, to achieve the target height, and the reduction amount of each forging press in the drawing process may be 10 to 30%, specifically 10%, 15%, 20%, 25%, or 30%. In the embodiment of the present invention, the upsetting process, which consists of one forging press to achieve the target height, is to ensure forging penetration, and the number of forging presses in the drawing process is limited to the above range, with the aim of avoiding insufficient deformation due to insufficient number of presses and cracking due to excessive temperature drop caused by excessive forging presses. 【0027】 In one embodiment of the present invention, the temperature of the heat retention treatment for each upsetting and drawing batch may be independently 420 to 500°C, specifically 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, or 500°C, and the heat retention treatment time may be independently 2 to 3 hours, specifically 2 hours, 2.5 hours, or 3 hours. In this embodiment of the present invention, by limiting the heat retention treatment conditions to the above range, not only is the risk of over-combustion avoided, but the good plastic deformation capacity of the magnesium alloy is also ensured, as too high a temperature poses a risk of over-combustion, and too low a temperature makes it prone to cracking. 【0028】 In one embodiment of the present invention, the length of the upset-drawn forged material may be 400 to 700 mm, specifically 400 mm, 450 mm, 500 mm, 550 mm, 600 mm, 650 mm, or 700 mm. 【0029】 As an embodiment of the present invention, taking as an example the number of upsetting and drawing ingots is two, specifically, the homogenized ingot is subjected to the following in sequence: first upsetting, first drawing, first heat retention, second upsetting, second drawing, and second heat retention, and the length of the forged material after the first upsetting may be 400 to 600 mm (specifically 400 mm, 450 mm, 500 mm, 550 mm, or 600 mm, preferably 400 mm), and the length of the forged material after the first drawing may be 500 to 700 mm (specifically 500 mm, 550 mm, 600 mm, 650 mm, or 700 mm, preferably The length of the forged material may be 400 to 600 mm (specifically 400 mm, 450 mm, 500 mm, 550 mm, or 600 mm, preferably 450 mm), and the length of the forged material after the second drawing process may be 500 to 700 mm (specifically 500 mm, 550 mm, 600 mm, or 700 mm, preferably 500 mm), and the forged material may then be 500 to 700 mm (specifically 500 mm, 550 mm, 600 mm, 65), and the forged material may then be 500 to 700 mm (specifically 500 mm, 550 mm, 600 mm, or 650 mm, preferably 500 mm), and the forged material may then be 500 to 700 mm (specifically 500 mm, 550 mm, 600 mm, 650 mm, or 700 mm), and the forged material may then be 500 to 700 mm (specifically 500 mm, 550 mm, 600 mm, or 700 mm), and the forged material may then be 50 【0030】 In one embodiment of the present invention, the upsetting and drawing process can be performed specifically by a hydraulic press, and the upper and lower die plates to be used can be preheated to 360-460°C, specifically 400°C, before the upsetting and drawing process. 【0031】 After obtaining an upset-drawn forged material, the present invention sequentially performs upsetting and cylindrical forging shaping on the upset-drawn forged material to obtain a cylindrical forged material. In the present invention, the reduction amount in the main deformation direction during upsetting of the upset-drawn forged material is 30% or more, for example, it may be 30-50%, specifically 30%, 35%, 40%, 45%, or 50%, and the forging press speed is 1-10 mm / s, and may be even 1-5 mm / s, specifically 1 mm / s, 2 mm / s, 3 mm / s, 4 mm / s, or 5 mm / s. In one embodiment of the present invention, upsetting is performed on the upset-drawn forged material by performing one forging press to reach a target height. In the present invention, the cylindrical forging process includes multiple cylindrical forging processes performed along the radial direction, wherein the deformation amount of each cylindrical forging process does not exceed 8%, and may be, for example, 3 to 8%, specifically 3%, 4%, 5%, 6%, 7%, or 8%. In one embodiment of the present invention, the number of cylindrical forging processes does not exceed 8, and may be, for example, 3 to 8, specifically 3, 4, 5, 6, 7, or 8. 【0032】 As one embodiment of the present invention, the cylindrical forged material is round in shape, the diameter of the end face may be 700 to 850 mm, specifically 700 mm, 730 mm, 745 mm, 780 mm, 810 mm, or 850 mm, preferably 745 mm, the maximum diameter may be 770 to 850 mm, specifically 770 mm, 800 mm, 820 mm, or 850 mm, preferably 770 mm, and the height may be 250 to 340 mm, specifically 250 mm, 280 mm, 300 mm, 330 mm, 332 mm, or 340 mm, preferably 330 to 332 mm. 【0033】 In one embodiment of the present invention, specifically, one upsetting treatment is performed on the upset-drawn forged material to obtain a cylindrical forged material with a height of 350 to 450 mm (specifically, it may be 440 to 450 mm). Next, the cylindrical surface is subjected to a cylindrical forging treatment eight or fewer times until the bulge in the waist disappears (i.e., the forging press direction covers the entire circumferential direction of the forged material). Finally, it is cooled in air to obtain a round, mochi-shaped forged material (i.e., a cylindrical forged material). In this embodiment of the present invention, the purpose of performing multiple multidirectional cylindrical forging treatments with small deformation amounts along the radial direction is to increase the deformation amount of the outer surface of the cylindrical forged material, improve the uniformity of the structure, reduce the amount of subsequent machining, and improve the utilization rate of the material. 【0034】 In the embodiments of the present invention, the homogenized ingot is subjected to upsetting and drawing, and the upsetting and drawing forged material is sequentially subjected to upsetting and cylindrical forging. Specifically, the material is divided by free forging, and by rationally setting the forging press temperature (i.e., the temperature of the heat retention treatment), forging press speed, number of forging presses, and reduction amount, it is advantageous to avoid cracking of the magnesium alloy while maintaining good plastic deformation capacity. Embodiments of the present invention have been verified through numerous experiments, and as a result, by performing multiple multi-directional cylindrical forging processes with small strain amounts using a forging press temperature of 420-500°C, a single reduction amount of 30-50% (specifically, possibly 40%) for upsetting, and a single reduction amount of 10-30% (specifically, possibly 15%) for drawing, the objectives of improving the uniformity of the material structure, reducing the bulge width of the waist of the forged material, reducing the amount of subsequent machining, and improving material utilization are achieved. This series of forging press processes, when combined with a forging press speed of 1-10 mm / s (furthermore, possibly 1-5 mm / s), successfully forges a round, crack-free forged material (i.e., cylindrical forged material). 【0035】 After obtaining a cylindrical forged material, the present invention performs die forging on the cylindrical forged material to obtain a formed forged product. In one embodiment of the present invention, the cylindrical forged material is further subjected to a second heat treatment before die forging, the temperature of the second heat treatment may be 420 to 500°C, specifically 420°C, 430°C, 440°C, 450°C, 460°C, 470°C, 480°C, 490°C, or 500°C, and the holding time may be 7 to 11 hours, specifically 7 hours, 8 hours, 9 hours, 10 hours, or 11 hours. In the embodiment of the present invention, by limiting the conditions of the second heat treatment to the above range, the risk of over-combustion is avoided, as well as the good plastic deformation ability of the magnesium alloy is ensured, as too high a temperature poses a risk of over-combustion, and too low a temperature makes it prone to cracking. 【0036】 In one embodiment of the present invention, before the second heat treatment, the cylindrical forged material is turned into a cylindrical forged material with a diameter of 720 to 820 mm (specifically, it may be 750 mm) and a height of 280 to 340 mm (specifically, it may be 325 mm), inspected for defects, then a chamfer of R20 is set on both sides, and a concave positioning recess with a depth of 5 mm and a diameter of 100 mm is polished in the center of both sides of the round forged material. In this embodiment of the present invention, setting a chamfer of dimension R20 on both the upper and lower sides of the round forged material before die forging is to avoid the problem of local stress concentration in the forged material during the die forging process, which makes it prone to cracking, and polishing a concave positioning recess on both sides of the round forged material is to ensure that the forged material can be centered during the subsequent die forging process, and that the metal material flows uniformly along the circumferential direction. 【0037】 As one embodiment of the present invention, the die used for die forging includes an upper die and a lower die, the upper die being a frustoconical punch with a demolding angle of 5°, the lower die (female die) having a straight wall cavity in the portion of its bottom with a height of ≤100 mm (i.e., 0 to 100 mm), and the lower die (female die) having an inclined wall cavity with a demolding angle of 0.5° in the portion of its bottom with a height of >100 mm. Before performing die forging, the upper and lower dies can be preheated to 380 to 480°C (specifically, 400°C) and kept warm for 15 hours. In the embodiments of the present invention, designing the bottom of the female mold as a straight-walled cavity allows the forging material to be centered during subsequent die forging, ensuring that the metal material flows uniformly along the circumferential direction. Preheating the upper and lower molds to the above temperature range compensates for temperature loss in the forged product during the forging process, provides good heat retention to the forged product, and not only ensures the deformation capacity of the magnesium alloy but also improves production efficiency to some extent. 【0038】 In this invention, the press speed (lower die descent speed) for die forging is 0.1 to 6 mm / s, and specifically may be 0.1 mm / s, 0.2 mm / s, 0.3 mm / s, 0.4 mm / s, 0.6 mm / s, 0.8 mm / s, 1 mm / s, 2 mm / s, 3 mm / s, 4 mm / s, 5 mm / s, or 6 mm / s. By employing die forging and a program-controlled press speed, this invention ensures consistency in the performance of each product, guarantees accurate external dimensions of the product, and provides assurance for mass production. As one embodiment of the present invention, when performing die forging, the die is pressed until it is clamped (specifically, the forging press can be stopped when the upper die is pressed to an unreduced amount of 35-40 mm), and an inclined wall cylindrical member having a bottom is obtained, the height of which is 700-800 mm, the outer diameter of the bottom is 720-760 mm, the outer diameter of the opening is 820-860 mm, the wall thickness is 50-90 mm, and the thickness of the bottom is 30-50 mm. After demolding the inclined wall cylindrical member, it is quenched and cooled in water to obtain a formed forged product. As another embodiment of the present invention, when performing die forging, when pressing the upper die to a predetermined unreduced amount, the metal material is prevented from overflowing from the female die opening and from coming into direct contact with the air over a large area, thereby reducing the temperature drop at the opening of the forged product and improving the consistency of the performance of each part of the forged product. In one embodiment of the present invention, the total transition time for quenching and cooling the inclined wall cylindrical member in water after demolding may be less than 300 s, and the total usage time from when the inclined wall cylindrical member contacts the water surface until it is completely immersed in water may be 15 to 20 s. 【0039】 In press deformation of large magnesium alloys, a large amount of deformation heat is easily generated, leading to over-combustion of the forged material. The surface is subjected to frictional forces between the extrusion cylinder and extrusion die, resulting in uneven deformation and a tendency for surface cracking. In the embodiments of the present invention, rationally setting the die forging temperature and die forging speed is advantageous for smooth die forging, and designing a concave positioning recess during the die forging stage is advantageous for uniform flow of the metal material along the circumferential direction. Embodiments of the present invention have been verified by numerous experiments, which have shown that by employing a press temperature of 420-500°C (i.e., the temperature of the second heat treatment) and a press speed of 0.1-6 mm / s, it is possible to successfully forge formed forged products without surface cracks. 【0040】 After obtaining a formed forged product, the present invention performs a T5 heat treatment on the formed forged product to obtain a VW93M magnesium alloy inclined wall cylindrical forged product. In one embodiment of the present invention, the temperature of the T5 heat treatment may be 200 to 250°C, specifically 200°C, 210°C, 220°C, 230°C, 240°C, or 250°C, and the holding time may be 14 to 24 hours, specifically 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, or 24 hours, and after the holding time is completed, it can be removed from the furnace and air-cooled. In the embodiment of the present invention, by performing a T5 heat treatment on the formed forged product under the above conditions, precipitation strengthening is formed in the alloy matrix, and excellent overall mechanical properties are obtained. 【0041】 This invention successfully manufactures semi-finished magnesium alloy inclined-wall cylindrical forgings for missile cabins, which are highly tough and can withstand a wide temperature range. They are based on a high-strength, heat-resistant VW93M magnesium alloy and employ a composite forming process of upsetting, drawing, cylindrical forging, and die forging. The result is a semi-finished product with no surface cracks, uniform microstructure, internal metallurgical quality meeting Class A standards in ultrasonic testing, and excellent overall mechanical properties. This can be used to replace large inclined-wall cylindrical complex members made of other materials, which are equipped with longitudinal reinforcing ribs on the cylindrical wall, a bottom plate, and end frames or flange rings at both ends of the cylindrical wall. This solves the problem of difficulty in forming semi-finished products with complex inclined-wall cylindrical structures. At the same time, the die forging extrusion integral forming process of this invention eliminates bolted connections between the cabin facade and the cabin bottom end frame (flange ring) in conventional missile cabin structures, fundamentally improving structural reliability, avoiding the risk of bolted connection member failure under overload conditions at the connection point, avoiding the risk of electrochemical corrosion due to the connection of dissimilar metal materials, and is advantageous for long-term storage and use in the harsh environment of missile cabins. For missile-type weapons, using magnesium alloy material throughout the cabin has significant application value as it helps reduce weight, improve fuel efficiency, and enhance guidance accuracy. 【0042】 The present invention provides a VW93M magnesium alloy inclined wall cylindrical forging manufactured by the manufacturing method described in the above technical solution. In one embodiment of the present invention, the dimensions of the VW93M magnesium alloy inclined wall cylindrical forging may be a height of 700 to 800 mm (specifically 730 to 736 mm), an outer diameter of the bottom of 720 to 760 mm (specifically 740 to 750 mm), an outer diameter of the opening of 820 to 860 mm (specifically 830 to 840 mm), a wall thickness of 50 to 90 mm (specifically 55 to 65 mm), and a bottom thickness of 30 to 50 mm (specifically 35 to 40 mm). 【0043】 As one embodiment of the present invention, the VW93M magnesium alloy inclined wall cylindrical forged product has excellent overall mechanical properties. 【0044】 At -55°C, the axial yield strength is ≥350 MPa (specifically, it may be 366 MPa), the tensile strength is ≥440 MPa (specifically, it may be 466 MPa), and the elongation is ≥9% (specifically, it may be 10.1%). At -55°C, the tangential yield strength is ≥320 MPa (specifically, it may be 337 MPa), the tensile strength is ≥430 MPa (specifically, it may be 441 MPa), and the elongation is ≥9% (specifically, it may be 11.4%). At -55°C, the radial yield strength is ≥240 MPa (specifically, it may be 253 MPa), the tensile strength is ≥370 MPa (specifically, it may be 405 MPa), and the elongation is ≥7% (specifically, it may be 7.5%). 【0045】 At room temperature, the axial yield strength is ≥240 MPa (specifically 256-261 MPa), tensile strength is ≥380 MPa (specifically 404-410 MPa), and elongation is ≥8% (specifically 8.2-11.9%). At room temperature, the tangential yield strength is ≥240 MPa (specifically 243-265 MPa), tensile strength is ≥370 MPa (specifically 381-403 MPa), and elongation is ≥8% (specifically 9.0-11.9%). At room temperature, the radial yield strength is ≥200 MPa (specifically 215-234 MPa), tensile strength is ≥340 MPa (specifically 355-375 MPa), and elongation is ≥5% (specifically 7.0-8.1%). 【0046】 At a high temperature of 200°C, the axial yield strength is ≥220 MPa (specifically, it may be 241-251 MPa), the tensile strength is ≥350 MPa (specifically, it may be 352-359 MPa), and the elongation is ≥10% (specifically, it may be 11.3-14.1%). At a high temperature of 200°C, the tangential yield strength is ≥220 MPa (specifically, it may be 228-248 MPa), the tensile strength is ≥330 MPa (specifically, it may be 340-352 MPa), and the elongation is ≥10% (specifically, it may be 10.8-13.1%). At a high temperature of 200°C, the radial yield strength is ≥200 MPa (specifically, it may be 208-230 MPa), the tensile strength is ≥300 MPa (specifically, it may be 319-343 MPa), and the elongation is ≥10% (specifically, it may be 10.5-12.3%). 【0047】 The present invention provides the use of the VW93M magnesium alloy inclined wall cylindrical forging described in the above technical solution in the manufacture of a missile cabin. The present invention employs a magnesium alloy improved based on the Mg-Gd-Y-Zr alloy system, and the VW93M magnesium alloy inclined wall cylindrical forging manufactured by forging extrusion integral molding technology can be used as a semi-finished product of a missile cabin, and a missile cabin structure in which the outer plate, reinforcing ribs and flange ring (end frame) are integrated by machining in the later stages can be manufactured. On the one hand, the use of magnesium alloy, which is a lightweight metallic material, significantly reduces the weight of the cabin, and on the other hand, this type of integral molding process eliminates the mechanical connection between the truss and the outer plate of the cylindrical side wall of the cabin section, and between the truss and the flange ring (end frame) at the bottom of the cylindrical section of the cabin section, improving structural reliability and avoiding the risk of electrochemical corrosion between dissimilar metallic materials, which is advantageous for long-term storage and use of the missile cabin in harsh environments. The present invention does not particularly limit the specific method of use of the VW93M magnesium alloy inclined wall cylindrical forging, and any method familiar to those skilled in the art may be used. 【0048】 The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Clearly, the embodiments described are only a subset of the present invention, not all embodiments. All other embodiments obtained by those skilled in the art without creative work based on the embodiments of the present invention are within the scope of the protection of the present invention. 【0049】 Example 1 The magnesium alloy in this embodiment has the following composition: Mg-8.98Gd-2.33Y-0.44Zr-0.24Ag-0.28Er, that is, by mass percentage, it contains Gd 8.98%, Y 2.33%, Zr 0.44%, Ag 0.24%, and Er 0.28%, with the remainder being Mg and unavoidable impurities. The method for manufacturing a sloping wall cylindrical forging using a magnesium alloy of the above composition includes the following steps. 【0050】 (1) Based on the composition of the magnesium alloy, a magnesium alloy ingot with a diameter of 460 mm is manufactured by a semi-continuous casting method (shown in Figure 1). 【0051】 (2) The magnesium alloy ingot is heated to 400°C together with the furnace and kept at that temperature for 5 hours, then heated to 510°C and kept at that temperature for 20 hours, and then air-cooled to room temperature to obtain a homogenized ingot. 【0052】 (3) The homogenized ingot is subjected to mechanical turning, flaw detection, and cutting in sequence to obtain a cast rod with a diameter of 420 mm and a length of 1250 mm. 【0053】 (4) The cast rod is heated to 500°C and kept warm for 7 hours. After warming, the cast rod is placed in a hydraulic press (the upper and lower free-forging die plates to be used are preheated to 400°C) and upset and draw-out is performed twice to obtain upset and draw-forged material. Specifically, the first upset and draw-out involves sequentially performing one upset process (forging press once to reach a target height, specifically 400 mm) and one draw-out process (forging press five times to reach a target height, specifically 500 mm), and then keeping warm at 480°C for 2 hours. Specifically, the second upset and draw-out involves sequentially performing one upset process (forging press once to reach a target height, specifically 450 mm) and one draw-out process (forging press five times to reach a target height, specifically 500 mm), and then keeping warm at 470°C for 2.5 hours. The forging press speed for each upsetting and drawing process is 3 mm / s. The reduction amount in the main deformation direction (i.e., the axial direction of the cast bar) for each upsetting process is 40%, and the reduction amount for each drawing process is 15%. 【0054】 The uplifted and drawn forged material is subjected to one uplift process and one cylindrical forging process in sequence, with a forging press speed of 3 mm / s for the uplift process and a reduction of 40% in the main deformation direction (i.e., the axial direction of the cast rod). The uplift process involves one forging press to reach a target height (specifically 450 mm), and the one cylindrical forging process includes four cylindrical forging processes (the deformation amount of each cylindrical forging process does not exceed 8%). The cylindrical forging process does not cause the waist of the forged material to bulge (i.e., the forging press direction covers the circumferential direction of the entire forged material), and finally, it is cooled in air to obtain a round, mochi-shaped forged material with an end face diameter of 745 mm, a maximum diameter of 770 mm, and a height of 330 mm (i.e., the cylindrical forged material shown in Figure 2). 【0055】 (5) The cylindrical forged material is turned into a cylindrical forged material with a diameter of 750 mm and a height of 325 mm, inspected for defects, then chamfered on both sides with a radius of R20 (fillet radius of R20), and concave positioning recesses with a depth of 5 mm and a diameter of 100 mm are polished in the center of both sides of the forged material. The obtained forged material is heated to 480°C and kept warm for 10 hours, and then die forging is performed. The die used for die forging includes an upper die and a lower die. The upper die is a frustoconical punch with a demolding angle of 5°, the lower die (female die) has a straight wall cavity in the lower part with a height of ≤100 mm (i.e., 0 to 100 mm), and the lower die (female die) has an inclined wall cavity with a demolding angle of 0.5° in the lower part with a height of >100 mm. The upper and lower dies are preheated to 400°C before use and kept warm for 15 hours. During the die forging process, the lowering speed of the upper die is 1 mm / s, and the press is continued until the die is clamped (specifically, the forging press is stopped when the upper die is pressed down to an unreduced amount of 40 mm), to obtain a cylindrical member with an inclined wall and a bottom, the height of which is 730 mm, the outer diameter of the bottom is 740 mm, the outer diameter of the opening is 830 mm, the wall thickness is 55 mm, and the thickness of the bottom is 40 mm. After that, the mold is released and the member is quenched and cooled in water to obtain a formed forged product. 【0056】 (6) The formed forged product is subjected to T5 heat treatment. Specifically, the formed forged product is heated to 230°C and kept warm for 22 hours. After the warming period, it is removed from the furnace and air-cooled to obtain a VW93M magnesium alloy inclined wall cylindrical forged product (shown in Figure 3). 【0057】 Example 2 (1) A cast rod with a diameter of 420 mm and a length of 900 mm is manufactured by referring to the method of Example 1. 【0058】 (2) The cast rod is heated to 500°C and kept warm for 7 hours. After warming, the cast rod is placed in a hydraulic press (the upper and lower free-forging die plates to be used are preheated to 200°C) and upset and draw-out is performed twice to obtain upset and draw-forged material. Specifically, the first upset and draw-out involves sequentially performing one upset process (forging press once to reach a target height, specifically 400 mm) and one draw-out process (forging press five times to reach a target height, specifically 500 mm), and then keeping warm at 480°C for 2 hours. Specifically, the second upset and draw-out involves sequentially performing one upset process (forging press once to reach a target height, specifically 450 mm) and one draw-out process (forging press five times to reach a target height, specifically 500 mm), and then keeping warm at 470°C for 2.5 hours. The forging press speed for each upsetting and drawing process is 3 mm / s. The reduction amount in the main deformation direction (i.e., the axial direction of the cast bar) for each upsetting process is 40%, and the reduction amount for each drawing process is 15%. 【0059】 The uplifted and drawn forged material is subjected to one uplift process and one cylindrical forging process in sequence, with a forging press speed of 3 mm / s for the uplift process and a reduction of 40% in the main deformation direction (i.e., the axial direction of the cast rod). The uplift process involves one forging press to reach a target height (specifically 450 mm), and the one cylindrical forging process includes four cylindrical forging processes (the deformation amount of each cylindrical forging process does not exceed 8%), and the cylindrical forging process does not cause the waist of the forged material to bulge (i.e., the forging press direction covers the circumferential direction of the entire forged material). Finally, it is cooled in air to obtain a round, mochi-shaped forged material (i.e., cylindrical forged material) with an end face diameter of 745 mm, a maximum diameter of 770 mm, and a height of 332 mm. 【0060】 (3) The cylindrical forged material is turned into a round forged material with a diameter of 750 mm and a height of 325 mm, inspected for defects, then chamfered on both sides with a radius of R20 (fillet radius of R20), and concave positioning recesses with a depth of 5 mm and a diameter of 100 mm are polished in the center of both sides of the forged material. The obtained forged material is heated to 480°C and kept warm for 10 hours, and then die forging is performed. The die used for die forging includes an upper die and a lower die. The upper die is a frustoconical punch with a demolding angle of 5°, the lower die (female die) has a straight wall cavity in the lower part with a height of ≤100 mm (i.e., 0 to 100 mm), and the lower die (female die) has an inclined wall cavity with a demolding angle of 0.5° in the lower part with a height of >100 mm. The upper and lower dies are preheated to 400°C before use and kept warm for 15 hours. During the die forging process, the lowering speed of the upper die was 2 mm / s, and the press was continued until the die was clamped (specifically, the forging press was stopped when the upper die was pressed down to an unreduced amount of 35 mm), to obtain a cylindrical member with an inclined wall and a bottom, the height of which was 736 mm, the outer diameter of the bottom being 740 mm, the outer diameter of the opening being 830 mm, the wall thickness being 55 mm, and the thickness of the bottom being 35 mm. After that, the mold was released and the product was quenched and cooled in water to obtain a formed forged product. 【0061】 (4) The formed forged product is subjected to T5 heat treatment. Specifically, the formed forged product is heated to 230°C and kept warm for 22 hours. After the warming period, it is removed from the furnace and air-cooled to obtain a VW93M magnesium alloy inclined wall cylindrical forged product. 【0062】 Test Example 1 The VW93M magnesium alloy inclined wall cylindrical forging produced in Example 1 was characterized, and the specific results are as follows. 【0063】 Figure 4 is a low-magnification characterization diagram of the microstructure of the VW93M magnesium alloy inclined-wall cylindrical forging produced in Example 1. The results show that the alloy structure of the VW93M magnesium alloy inclined-wall cylindrical forging is consistent and there are no obvious coarse precipitates or inclusions. 【0064】 Figure 5 shows the high-magnification electron backscatter diffraction (EBSD) characterization of the VW93M magnesium alloy inclined-wall cylindrical forging produced in Example 1, where (a) is the contrast diagram and (b) is the IPF diagram. The results indicate that the alloy of the VW93M magnesium alloy inclined-wall cylindrical forging has recrystallized sufficiently and that the microstructure is uniform. 【0065】 Figure 6 shows the morphology of the tensile fracture surface of the VW93M magnesium alloy inclined wall cylindrical forging manufactured in Example 1 (tensile sample taken along the axial direction of the forging). The results show that the VW93M magnesium alloy inclined wall cylindrical forging does not contain any obvious non-metallic inclusions. 【0066】 Test Example 2 The mechanical properties of the VW93M magnesium alloy inclined-wall cylindrical forgings produced in Example 1 and Example 2 were tested according to GB / T228.1-2021, and the results are shown in Tables 1 to 3. From Tables 1 to 3, it was found that the VW93M magnesium alloy inclined-wall cylindrical forgings produced by the present invention have excellent mechanical properties. 【0067】 Table 1 Mechanical properties of VW93M magnesium alloy inclined wall cylindrical forgings in Examples 1-2 (at room temperature) TIFF2026100784000002.tif227150 【0068】 Table 2 Mechanical properties of VW93M magnesium alloy inclined wall cylindrical forgings in Examples 1-2 (200°C) TIFF2026100784000003.tif236149 【0069】 Table 3 Mechanical properties of VW93M magnesium alloy inclined wall cylindrical forgings in Example 1 (-55°C) TIFF2026100784000004.tif70150 【0070】 The foregoing are merely preferred embodiments of the present invention, and those skilled in the art can make some modifications and improvements without departing from the principles of the present invention, and these modifications and improvements should be considered within the scope of protection.

Claims

[Claim 1] A method for manufacturing a VW93M magnesium alloy inclined wall cylindrical forging, The process involves performing stepwise homogenization annealing on a VW93M magnesium alloy ingot to obtain a homogenized ingot, The homogenized ingot is subjected to upsetting and drawing to obtain upsetting and drawing forged material, the number of upsetting and drawing steps is 1 to 2, each upsetting and drawing step includes sequential upsetting, drawing, and heat retention, the reduction amount in the main deformation direction during upsetting in each upsetting and drawing step is 30% or more, the forging press speed for each upsetting and drawing step is independently 1 to 10 mm / s, each upsetting and drawing step involves one forging press to reach the target height, each drawing step involves 8 to 12 forging presses to reach the target height, each heat retention temperature for each upsetting and drawing step is independently 420 to 500°C, and each heat retention time for each upsetting and drawing step is independently 2 to 3 hours. The process involves sequentially performing an upsetting treatment and cylindrical forging on the upset-drawn forged material to obtain a cylindrical forged material, wherein the reduction amount in the main deformation direction during the upsetting treatment on the upset-drawn forged material is 30% or more, the forging press speed is 1 to 10 mm / s, the cylindrical forging shaping includes multiple cylindrical forging treatments performed in the radial direction, the deformation amount of each cylindrical forging treatment does not exceed 8%, and an upsetting treatment is performed on the upset-drawn forged material with one forging press to achieve a target height, the number of cylindrical forging treatments does not exceed 8. The cylindrical forged material is subjected to die forging to obtain a formed forged product, and the press speed for die forging is 0.1 to 6 mm / s. A manufacturing method characterized by comprising the step of performing a T5 heat treatment on the formed forged product to obtain the VW93M magnesium alloy inclined wall cylindrical forged product. [Claim 2] The manufacturing method according to claim 1, characterized in that the diameter of the VW93M magnesium alloy ingot is 400 to 550 mm, the stepwise homogenization annealing includes sequentially performing a first annealing and a second annealing, the temperature of the first annealing is 400 to 440°C, the holding time for the first annealing is 5 to 8 hours, the temperature of the second annealing is 500 to 540°C, and the holding time for the second annealing is 20 to 25 hours. [Claim 3] The manufacturing method according to claim 2, further comprising separating the homogenized ingot before the upsetting and drawing process to obtain a cast rod having a diameter of 400 to 500 mm and a length of 800 to 1250 mm. [Claim 4] The manufacturing method according to claim 3, further comprising a first heat treatment between the separation and the upsetting and drawing of the mass, wherein the temperature of the first heat treatment is 420 to 530°C and the holding time of the first heat treatment is 7 to 11 hours. [Claim 5] The process further includes performing a second heat treatment on the cylindrical forging material before the die forging process, The manufacturing method according to claim 1, characterized in that the second heat treatment is performed at a temperature of 420 to 500°C and for a holding time of 7 to 11 hours. [Claim 6] The manufacturing method according to claim 1, characterized in that the T5 heat treatment is performed at a temperature of 200 to 250°C and for a holding time of 14 to 24 hours.

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