Spherical cavity part and preparation method and application thereof

Abstract

The invention belongs to the technical field of part preparation, and particularly discloses a spherical cavity part and a preparation method and application thereof.The preparation method is based on differential pressure forming and vacuum heat treatment and comprises the steps that firstly, a deformation plate and a fixing part are welded to form a closed space, and the deformation plate is made of high-quality steel and other materials with the room-temperature ductility larger than 25%; argon tungsten-arc welding is adopted for multi-layer and multi-pass welding, and it is guaranteed that the weld strength is larger than 600 MPa; and then heating and vacuumizing in a vacuum heat treatment furnace, bulging the deformed plate into a hemisphere by utilizing pressure difference, and finally cutting and welding to obtain a target spherical cavity part. The problems that in a traditional technology, spherical cavity parts have many defects, the material utilization rate is low, and precision is poor are solved, the material utilization rate is greatly increased, the qualified rate of finished products reaches 90% or above, cost is reduced, the period is shortened, and the prepared spherical cavity parts can be applied to the fields of aerospace, chemical engineering, energy and the like.

Description

Technical Field

[0001] The present invention belongs to the technical field of parts preparation, and in particular relates to a spherical cavity part and a preparation method and application thereof. Background Art

[0002] Spherical cavity components are widely used in a wide range of fields, including aerospace, chemical engineering, and energy. Examples include propellant tanks in aerospace, reaction vessels in chemical engineering, and gas storage devices in energy. These components require excellent sealing, structural strength, and dimensional accuracy to ensure stable operation under complex operating conditions. However, current methods for fabricating spherical cavity components present numerous challenges.

[0003] Traditionally, casting processes for spherical cavity parts are prone to uneven shrinkage during solidification, leading to defects such as pores and shrinkage within the parts. This not only reduces the strength and sealing of the parts but can also pose safety risks such as leakage and rupture during use. Furthermore, casting processes are highly dependent on molds, resulting in long mold design and manufacturing cycles and high costs, making them difficult to meet the demands of small-batch, high-variety production. Some companies use machining to produce spherical cavity parts, using cutting, grinding, and other methods to shape the raw materials into the desired shape. However, this method results in significant material removal and material utilization rates typically below 30%, resulting in significant resource waste and increased production costs. Furthermore, the complex curved structures of spherical cavities necessitate multiple clamping and positioning during machining. Machining accuracy is significantly affected by factors such as equipment accuracy and tool wear, making it difficult to ensure dimensional accuracy and surface quality. This is particularly true for high-precision spherical cavity parts for aerospace applications, where the yield rate of finished products after machining is low. Therefore, there is an urgent need to develop new methods for preparing spherical cavity parts to overcome the shortcomings of existing technologies.

[0004] In view of this, this invention is proposed. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a spherical cavity part and its preparation method and application. The present invention is based on a spherical cavity part preparation method based on pressure differential forming and vacuum heat treatment. Through precise pressure differential control and heat treatment process, it can effectively solve the problems of many internal defects of parts, low material utilization, poor processing accuracy, low production efficiency and so on in the prior art, and significantly improve the comprehensive performance and preparation efficiency of spherical cavity parts.

[0006] The purpose of the present invention is to solve the problem through the following technical solutions:

[0007] In a first aspect, the present invention provides a method for preparing a spherical cavity part, the method being based on pressure differential forming and vacuum heat treatment, and specifically comprising the following steps:

[0008] S1. Welding the deformed plate required for preparing the spherical cavity part to the top of the fixing part, and forming a closed space corresponding to the spherical cavity part between the two after welding;

[0009] S2. Place the welded deformed plate and the fixing member in a vacuum heat treatment furnace, heat to a set temperature, and then evacuate the furnace to bulge the deformed plate into a hemispherical shape using a pressure difference;

[0010] S3. After the expansion is completed in the low-pressure and high-temperature environment of the vacuum furnace, the temperature of the vacuum furnace is first lowered to below 150°C, and then the vacuum furnace is inflated to atmospheric pressure. Finally, the expanded hemisphere is taken out of the vacuum furnace;

[0011] S4, performing wire cutting to separate the hemisphere;

[0012] S5. Weld the two hemispheres into a complete target spherical cavity part by submerged arc welding.

[0013] Furthermore, the deformable plate is made of a material with a room temperature elongation greater than 25%, and the material includes any one of high-quality steel, pure titanium plate or pure aluminum plate.

[0014] Furthermore, in S1, the deformable plate and the fixing piece are welded by tungsten inert gas arc welding, and the welding method is multi-layer and multi-pass welding, and the weld strength after welding is greater than 600 MPa.

[0015] Furthermore, in S1, the shape of the enclosed space is a hollow cylinder, and its volume is: V1 = π × (D / 2) 2 ×H;

[0016] Among them, V1 is the volume of the enclosed space; D is the diameter of the bottom of the hollow cylinder, which is also the diameter of the spherical cavity part; H is the height of the hollow cylinder.

[0017] Furthermore, in S2, the set temperature is 0.7-0.8 times the melting point of the deformed plate material, and the holding time in the vacuum heat treatment furnace is 2-8 hours, so as to soften the deformed plate.

[0018] Furthermore, in S2, after the vacuum heat treatment furnace is evacuated, the vacuum degree in the furnace reaches 1.0×10 -4 Pa below, at this time, the deformation plate forms a layer greater than 1.0×10 5 The pressure difference of Pa is used to cause the deformed plate to bulge into a hemisphere.

[0019] Furthermore, in S2, the volume of the hemisphere after expansion satisfies the following relationship:

[0020] P1V1 / T1=P2V2 / T2;

[0021] Among them, P1 is atmospheric pressure, V1 is the volume of the initial enclosed space, and T1 is room temperature; P2 is the air pressure inside the hemisphere after expansion, V2 is the volume of the hemisphere after expansion, and T2 is the heating temperature of the vacuum heat treatment furnace.

[0022] Furthermore, in S5, when the two hemispheres are welded by submerged arc welding, an I-shaped groove structure is adopted.

[0023] It should be noted that the present invention has no special requirements on the shape and material of the fixing member, as long as the fixing member does not deform when the deformable plate deforms during the heating process.

[0024] In a second aspect, the present invention further provides a spherical cavity part, which is prepared based on the above preparation method.

[0025] In a third aspect, the present invention provides an application based on the above-mentioned spherical cavity part, wherein the spherical cavity part is used for a propellant tank in the aerospace field, a reaction vessel in the chemical field, or a gas storage device in the energy field.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] The present invention is based on a preparation method of pressure differential forming and vacuum heat treatment. By precisely controlling process parameters, it avoids the problem of internal defects of parts in the casting process, greatly improves the utilization rate of materials, and ensures dimensional accuracy so that the qualified rate of finished products reaches more than 90%. At the same time, it simplifies the process flow, reduces mold, raw material and processing costs, and shortens the production cycle. It can be widely used in propellant tanks, reaction vessels, gas storage devices, etc. in the fields of aerospace, chemical industry, energy, etc., and significantly improves the comprehensive performance and preparation efficiency of spherical cavity parts. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, serve to explain the principles of the invention.

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0030] Figure 1 Flowchart of the method for preparing the spherical cavity part of the present invention;

[0031] Figure 2 This is a schematic diagram of the structure before expansion when preparing a spherical cavity part according to the present invention;

[0032] Figure 3 This is a schematic diagram of the structure after expansion when preparing a spherical cavity part in the present invention.

[0033] in:

[0034] 1 is a deformable plate; 2 is a fixing part. DETAILED DESCRIPTION

[0035] Exemplary embodiments will be described in detail herein, examples of which are illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all possible embodiments consistent with the present invention. Rather, they are merely examples of arrangements consistent with certain aspects of the present invention as detailed in the appended claims.

[0036] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the present invention is described in further detail below with reference to the accompanying drawings and embodiments.

[0037] See also Figure 1 The present invention provides a method for preparing a spherical cavity part, which specifically includes the following steps:

[0038] 1) Welding to form a closed space: The deformed plate 1 required for preparing the spherical cavity part is welded to the top of the fixing part 2, and tungsten inert gas arc welding is used in a multi-layer and multi-pass welding method to ensure that the weld strength after welding is greater than 600MPa, and a closed space corresponding to the target spherical cavity part is formed between the two. Figure 2 As shown. The shape of the enclosed space is a hollow cylinder, and its volume satisfies the formula V1=π×(D / 2)2×H, where V1 is the volume of the enclosed space, D is the diameter of the bottom of the hollow cylinder (equivalent to the diameter of the spherical cavity part), and H is the height of the hollow cylinder. By adjusting D and H, the required volume of the enclosed space can be determined, providing a basis for subsequent bulging. At the same time, the deformation plate 1 is made of a material with a room temperature elongation greater than 25%, including high-quality steel, pure titanium plate or pure aluminum plate, etc., to ensure that it has good deformation ability in subsequent hot processing and does not shrink and deform after cooling. In addition, the thickness of the deformation plate 1 is selected according to actual conditions and is generally set to 3mm to 10mm.

[0039] 2) Pressure differential bulging: Place the welded deformed plate 1 and the fixing part 2 in a vacuum heat treatment furnace and heat to 0.7 to 0.8 times the melting point of the deformed plate 1 material. Keep the temperature for 2 to 8 hours to fully soften the deformed plate 1. After reaching the set temperature, evacuate the vacuum heat treatment furnace to a vacuum degree of 1.0×10 -4 Pa below, at this time, the deformation plate 1 forms a larger than 1.0×10 5 Pa, under the action of this pressure difference, the deformed plate 1 bulges into a hemispherical shape, such as Figure 3 The volume of the hemisphere after bulging follows the relationship P1V1 / T1=P2V2 / T2; where P1 is atmospheric pressure, V1 is the volume of the initial enclosed space, T1 is room temperature, P2 is the pressure inside the hemisphere after bulging, V2 is the volume of the hemisphere after bulging, and T2 is the heating temperature of the vacuum heat treatment furnace. This formula can be used to accurately control the bulging process.

[0040] 3) Cooling and removal: After the expansion is completed in the low-pressure and high-temperature environment of the vacuum furnace, the cooling system of the vacuum furnace is started, and a step-by-step cooling method is adopted. The temperature is first reduced to 0.3 to 0.4 times the melting point of the deformed plate 1 at a rate of 10 to 15 ° C / min, and then the temperature is continued to be reduced to below 150 ° C at a rate of 5 to 8 ° C / min. During this process, the temperature changes in the vacuum furnace are monitored and recorded in real time to ensure a smooth cooling process and avoid internal stress or deformation of the hemisphere due to a sudden drop in temperature. When the temperature drops to the target value, high-purity nitrogen (purity ≥ 99.99%) is slowly filled into the vacuum furnace through the inflation valve, and the inflation speed is controlled at 0.05 to 0.1 MPa / min until the pressure in the furnace reaches atmospheric pressure. Finally, after confirming that the air pressure inside the furnace is consistent with the outside air pressure and the temperature is suitable for operation, open the vacuum furnace door, use a special high-temperature resistant clamp to carefully remove the expanded hemisphere, place it on a clean and flat cooling platform and let it cool naturally to room temperature to avoid scratches or bumps on the surface of the hemisphere, which will affect the quality of subsequent processing.

[0041] 4) Wire cutting and splitting: The hemisphere obtained by bulging is subjected to wire cutting to split it into two parts.

[0042] 5) Welding assembly: The two semicircular spheres are welded together by submerged arc welding, using an I-shaped groove structure during welding, and finally a complete target spherical cavity part is obtained.

[0043] In order to further verify the efficacy of the present invention, the inventors conducted the following specific experiments:

[0044] Example 1 (Preparation of an aluminum spherical cavity part with a diameter of 300 mm)

[0045] 1) Welding to Create a Confined Space: A pure aluminum plate with a room-temperature elongation greater than 30% was selected as the deforming plate 1, measuring Φ600 × 4 mm. A steel ingot measuring Φ400 × 250 mm was used as the fixing element 2. The pure aluminum plate was welded to the top of the aluminum ingot using a multi-pass, multi-layer tungsten inert gas arc welding method. Before welding, the weld area was cleaned to remove surface oil and oxide film. During welding, the welding current was controlled at 70A and the welding voltage was 10V. Three layers were welded, and the weld seam was polished after each layer to ensure a smooth surface. Post-weld testing confirmed a weld strength of 650 MPa.

[0046] Determine the diameter D of the target spherical cavity part to be 300 mm. According to the formula H=V2*P2*T1 / (P1*T2*0.7854*D 2 ) mm. To ensure the bulging effect, the height of the hollow cylinder is selected as H = 20 mm, so the volume of the enclosed space V1 = π × (300 / 2)2 × 20 ≈ 1413000 mm3. Through precise processing, a hollow cylindrical enclosed space that meets the volume requirements is formed between the deformable plate 1 and the fixing member 2.

[0047] 2) Pressure differential bulging: Place the welded components in a vacuum heat treatment furnace. Given that the melting point of pure aluminum is 660°C, set the heating temperature to 660×0.8=528°C. Heat the vacuum heat treatment furnace to the set temperature at a heating rate of 50°C / h and hold for 2 hours to fully soften the aluminum. Once the temperature stabilizes, start the vacuum pump and draw the vacuum level in the furnace to 1.0×10 -4 Pa. At this time, the pressure difference formed inside and outside the deformed plate 1 is greater than 1.0×10 5 Pa, the pure aluminum plate gradually expands into a hemisphere under the action of the pressure difference. During the expansion process, the expansion volume is monitored and controlled in real time according to the formula P1V1 / T1=P2V2 / T2 to ensure that the hemisphere size meets the expected requirements.

[0048] 3) Cooling and removal: After the expansion is completed in the low-pressure and high-temperature environment of the vacuum furnace, the cooling system of the vacuum furnace is started, and a step-by-step cooling method is adopted. The temperature is first reduced to 200°C at a rate of 10°C / min, and then the temperature is continued to be reduced to 100°C at a rate of 5°C / min. During this process, the temperature changes in the vacuum furnace are monitored and recorded in real time to ensure that the cooling process is smooth and to avoid internal stress or deformation of the hemisphere due to a sudden drop in temperature. When the temperature drops to the target value, high-purity nitrogen (purity ≥99.99%) is slowly filled into the vacuum furnace through the inflation valve, and the inflation speed is controlled at 0.05MPa / min until the air pressure in the furnace reaches atmospheric pressure. Finally, after confirming that the air pressure in the furnace is consistent with the outside world and the temperature is suitable for operation, the vacuum furnace door is opened, and a special high-temperature resistant clamp is used to carefully remove the expanded hemisphere, and it is placed on a clean and flat cooling platform to cool naturally to room temperature to avoid scratches or bumps on the surface of the hemisphere, which affects the quality of subsequent processing.

[0049] 4) Wire Cutting: Using a high-precision wire cutting machine, a 0.15mm diameter molybdenum wire is used as the electrode wire, and the discharge gap is set to 0.02mm. The bulged hemisphere is cut according to the designed cutting path, splitting it into two parts. The cutting accuracy is controlled within ±0.05mm.

[0050] 5) Welding Assembly: The two semicircular spheres were welded using submerged arc welding. Before welding, the weld groove was cleaned to ensure it was free of oil and impurities. An I-shaped groove was used. During welding, the welding current was controlled at 300A, the arc voltage at 32V, and the welding speed at 300mm / min. After welding, the weld was polished and inspected for flaws. The test results showed that the weld was of good quality, free of defects such as pores and cracks. The final result was an aluminum spherical cavity part with a diameter of 300mm.

[0051] Testing showed that the aluminum spherical cavity component obtained in this example met design requirements for dimensional accuracy, exhibited excellent surface quality, and was free of internal defects. A hydraulic pressure test, maintained at 1.5 MPa for 30 minutes, revealed no leakage and excellent sealing. A tensile test also demonstrated that the tensile strength of the component met the performance requirements of pure aluminum plate, verifying the feasibility and effectiveness of the present preparation method.

[0052] Example 2 (Preparation of a titanium spherical cavity part with a diameter of 200 mm)

[0053] 1) Welding to Create a Confined Space: A pure titanium plate with a room-temperature elongation greater than 35% was selected as the deforming plate 1, measuring Φ400 × 4 mm. A steel ingot measuring Φ300 × 250 mm was used as the fixing element 2. The pure titanium plate was welded to the top of the titanium ingot using a multi-pass, multi-layer tungsten inert gas arc welding method. Before welding, the weld area was cleaned to remove surface oil and oxide film. During welding, the welding current was controlled at 90A and the welding voltage was 12V. Three welding layers were performed, and after each layer, the weld was polished to ensure a smooth surface. Post-weld testing confirmed a weld strength of 700 MPa.

[0054] Determine the diameter D of the target spherical cavity part to be 200 mm. According to the formula H=V2*P2*T1 / (P1*T2*0.7854*D 2 ) mm. To ensure the bulging effect, the height of the hollow cylinder is selected as H = 15 mm, so the volume of the enclosed space V1 = π × (200 / 2)2 × 15 ≈ 471000 mm3. Through precise processing, a hollow cylindrical enclosed space that meets the volume requirements is formed between the deformable plate 1 and the fixing member 2.

[0055] 2) Pressure differential bulging: Place the welded components in a vacuum heat treatment furnace. Given that the melting point of pure titanium is 1668°C, set the heating temperature to 1668×0.7≈1168°C. Heat the vacuum heat treatment furnace to the set temperature at a heating rate of 60°C / h and hold for 6 hours to fully soften the pure titanium. Once the temperature stabilizes, start the vacuum pump and reduce the vacuum level in the furnace to 1.0×10 -4 Pa. At this time, the pressure difference formed inside and outside the deformed plate 1 is greater than 1.0×105 Pa, the pure titanium plate gradually expands into a hemisphere under the action of the pressure difference. During the expansion process, the expansion volume is monitored and controlled in real time according to the formula P1V1 / T1=P2V2 / T2 to ensure that the hemisphere size meets the expected requirements.

[0056] 3) Cooling and removal: After the expansion is completed in the low-pressure and high-temperature environment of the vacuum furnace, the cooling system of the vacuum furnace is started, and a step-by-step cooling method is adopted. The temperature is first reduced to 670°C at a rate of 15°C / min, and then the temperature is continued to be reduced to 130°C at a rate of 8°C / min. During this process, the temperature changes in the vacuum furnace are monitored and recorded in real time to ensure that the cooling process is smooth and to avoid internal stress or deformation of the hemisphere due to a sudden drop in temperature. When the temperature drops to the target value, high-purity nitrogen (purity ≥99.99%) is slowly filled into the vacuum furnace through the inflation valve, and the inflation speed is controlled at 0.1MPa / min until the air pressure in the furnace reaches atmospheric pressure. Finally, after confirming that the air pressure in the furnace is consistent with the outside world and the temperature is suitable for operation, the vacuum furnace door is opened, and a special high-temperature resistant clamp is used to carefully remove the expanded hemisphere, and it is placed on a clean and flat cooling platform to cool naturally to room temperature to avoid scratches or bumps on the surface of the hemisphere, which affects the quality of subsequent processing.

[0057] 4) Wire Cutting: Using a high-precision wire cutting machine, a 0.25mm diameter molybdenum wire is used as the electrode wire, and the discharge gap is set to 0.02mm. The bulged hemisphere is cut according to the designed cutting path, splitting it into two parts. The cutting accuracy is controlled within ±0.05mm.

[0058] 5) Welding Assembly: The two semicircular spheres were welded using submerged arc welding. Before welding, the weld groove was cleaned to ensure it was free of oil and impurities. An I-shaped groove was used. During welding, the welding current was controlled at 200A and the arc voltage was 20V. After welding, the weld was polished and inspected for flaws. The results showed good weld quality, free of defects such as pores and cracks. The resulting titanium spherical cavity part had a diameter of 200mm.

[0059] Testing showed that the titanium spherical cavity component obtained in this example met design requirements for dimensional accuracy, exhibited excellent surface quality, and was free of internal defects. A hydraulic pressure test, maintaining a pressure of 1.5 MPa for 30 minutes, revealed no leakage and excellent sealing. A tensile test also demonstrated that the tensile strength of the component met the performance requirements of pure titanium plate material, verifying the feasibility and effectiveness of the preparation method.

[0060] Example 3 (Preparation of a 400mm diameter steel spherical cavity part)

[0061] 1) Welding to Create a Confined Space: A 20mm steel plate with a room-temperature elongation greater than 25% was selected as the deforming plate 1, measuring Φ700 x 8mm. A steel ingot measuring Φ500 x 400mm was used as the fixing element 2. The pure steel plate was welded to the top of the ingot using a multi-pass, multi-layer tungsten inert gas arc welding method. Before welding, the weld area was cleaned to remove surface oil and oxide film. During welding, the welding current was controlled at 120A and the voltage at 18V. Three layers were welded, and the weld seam was polished after each layer to ensure a smooth surface. Post-weld testing confirmed a weld strength of 680MPa.

[0062] Determine the diameter D of the target spherical cavity part to be 400 mm. According to the formula H=V2*P2*T1 / (P1*T2*0.7854*D 2 ) mm. To ensure the bulging effect, the height of the hollow cylinder is selected as H = 30 mm, so the volume of the enclosed space V1 = π × (400 / 2)2 × 30 ≈ 3768000 mm3. Through precise processing, a hollow cylindrical enclosed space that meets the volume requirements is formed between the deformable plate 1 and the fixing member 2.

[0063] 2) Pressure differential bulging: Place the welded components in a vacuum heat treatment furnace. Given that the melting point of 20 steel is approximately 1500°C, set the heating temperature to 1500×0.75=1125°C. Heat the vacuum heat treatment furnace to the set temperature at a heating rate of 60°C / h and hold for 8 hours to fully soften the pure aluminum plate. Once the temperature stabilizes, start the vacuum pump and draw the vacuum level in the furnace to 1.0×10 -4 Pa. At this time, the pressure difference formed inside and outside the deformed plate 1 is greater than 1.0×10 5 Pa, the pure aluminum plate gradually expands into a hemisphere under the action of the pressure difference. During the expansion process, the expansion volume is monitored and controlled in real time according to the formula P1V1 / T1=P2V2 / T2 to ensure that the hemisphere size meets the expected requirements.

[0064] 3) Cooling and removal: After the expansion is completed in the low-pressure and high-temperature environment of the vacuum furnace, the cooling system of the vacuum furnace is started, and a step-by-step cooling method is adopted. The temperature is first reduced to 525°C at a rate of 12°C / min, and then the temperature is continued to be reduced to 100°C at a rate of 6°C / min. During this process, the temperature changes in the vacuum furnace are monitored and recorded in real time to ensure that the cooling process is smooth and to avoid internal stress or deformation of the hemisphere due to a sudden drop in temperature. When the temperature drops to the target value, high-purity nitrogen (purity ≥99.99%) is slowly filled into the vacuum furnace through the inflation valve, and the inflation speed is controlled at 0.08MPa / min until the air pressure in the furnace reaches atmospheric pressure. Finally, after confirming that the air pressure in the furnace is consistent with the outside world and the temperature is suitable for operation, the vacuum furnace door is opened, and a special high-temperature resistant clamp is used to carefully remove the expanded hemisphere, and it is placed on a clean and flat cooling platform to cool naturally to room temperature to avoid scratches or bumps on the surface of the hemisphere, which affects the quality of subsequent processing.

[0065] 4) Wire Cutting: Using a high-precision wire cutting machine, a 0.2mm diameter molybdenum wire is used as the electrode wire, and the discharge gap is set to 0.02mm. The bulged hemisphere is cut according to the designed cutting path, dividing it into two parts. The cutting accuracy is controlled within ±0.05mm.

[0066] 5) Welding Assembly: The two semicircular spheres were welded using submerged arc welding. Before welding, the weld groove was cleaned to ensure it was free of oil and impurities. An I-shaped groove was used. During welding, the welding current was controlled at 200A, the arc voltage at 32V, and the welding speed at 300mm / min. After welding, the weld was polished and inspected for flaws. The test results showed that the weld was of good quality, free of defects such as pores and cracks. The final result was a 400mm diameter steel spherical cavity component.

[0067] Testing showed that the spherical steel cavity component obtained in this example met design requirements for dimensional accuracy, exhibited excellent surface quality, and was free of internal defects. A hydraulic pressure test, maintaining a pressure of 1.5 MPa for 30 minutes, revealed no leakage and excellent sealing. A tensile test also confirmed that the tensile strength of the component met the performance requirements of the steel plate material, verifying the feasibility and effectiveness of the preparation method.

[0068] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0069] It should be understood that the present invention is not limited to the above description and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing a spherical cavity part, characterized in that: The preparation method is based on pressure differential forming and vacuum heat treatment, and specifically includes the following steps: S1. Welding a deformed plate (1) required for preparing a spherical cavity part to the top of a fixing part (2), and forming a closed space corresponding to the spherical cavity part between the two after welding; S2, placing the welded deformed plate (1) and the fixing member (2) in a vacuum heat treatment furnace, heating them to a set temperature and then evacuating the furnace, and using the pressure difference to bulge the deformed plate (1) into a hemispherical shape; S3. After the expansion is completed in the low-pressure and high-temperature environment of the vacuum furnace, the temperature of the vacuum furnace is first lowered to below 150°C, and then the vacuum furnace is inflated to atmospheric pressure. Finally, the expanded hemisphere is taken out of the vacuum furnace; S4, performing wire cutting to separate the hemisphere; S5. Weld the two hemispheres into a complete target spherical cavity part by submerged arc welding.

2. The method for preparing a spherical cavity part according to claim 1, characterized in that: The deformed plate (1) is made of a material with a room temperature elongation greater than 25%, and the material includes any one of high-quality steel, pure titanium plate or pure aluminum plate.

3. The method for preparing a spherical cavity part according to claim 1, characterized in that: In S1, the deformable plate (1) and the fixing member (2) are welded by tungsten inert gas arc welding, and the welding method is multi-layer multi-pass welding, and the weld strength after welding is greater than 600 MPa.

4. The method for preparing a spherical cavity part according to claim 1, characterized in that: In S1, the shape of the enclosed space is a hollow cylinder, and its volume is: V1 = π × (D / 2) 2 ×H; Among them, V1 is the volume of the enclosed space; D is the diameter of the bottom of the hollow cylinder, which is also the diameter of the spherical cavity part; H is the height of the hollow cylinder.

5. The method for preparing a spherical cavity part according to claim 1, characterized in that: In S2, the set temperature is 0.7 to 0.8 times the melting point of the deformed plate (1) material, and the holding time in the vacuum heat treatment furnace is 2 to 8 hours, so as to soften the deformed plate (1).

6. The method for preparing a spherical cavity part according to claim 5, characterized in that: In S2, after the vacuum heat treatment furnace is evacuated, the vacuum degree in the furnace reaches 1.0×10 -4 Pa, the deformation plate (1) forms a larger than 1.0×10 5 The pressure difference of Pa is used to cause the deformable plate (1) to bulge into a hemispherical shape.

7. The method for preparing a spherical cavity part according to claim 1, characterized in that: In S2, the volume of the hemisphere after bulging satisfies the following relationship: P1V1 / T1=P2V2 / T2; Among them, P1 is atmospheric pressure, V1 is the volume of the initial enclosed space, and T1 is room temperature; P2 is the air pressure inside the hemisphere after expansion, V2 is the volume of the hemisphere after expansion, and T2 is the heating temperature of the vacuum heat treatment furnace.

8. The method for preparing a spherical cavity part according to claim 1, characterized in that: In S5, when the two hemispheres are welded by submerged arc welding, an I-shaped groove structure is adopted.

9. A spherical cavity part, characterized in that: The spherical cavity part is prepared based on the preparation method according to any one of claims 1 to 8.

10. An application of the spherical cavity part according to claim 9, characterized in that: The spherical cavity part is used for a propellant tank in the aerospace field, a reaction vessel in the chemical field, or a gas storage device in the energy field.

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