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CN-122007697-A - Large box bottom and forming method thereof

CN122007697ACN 122007697 ACN122007697 ACN 122007697ACN-122007697-A

Abstract

The invention discloses a large-sized box bottom and a forming method thereof, which relate to the field of rocket structure manufacturing, wherein the large-sized box bottom comprises a bottom cover and a ring section, the plurality of ring segments are sequentially overlapped, the two adjacent ring segments are fixedly sealed, and the outer side edge of one ring segment positioned at the end part is fixedly and hermetically connected with the side edge of the bottom cover. The invention discloses a large box bottom forming method, which comprises the steps of designing a large box bottom into a bottom cover and a plurality of ring segment structures, designing a flat circular ring blank according to the structural size of the bottom cover, forming the flat circular ring blank into the bottom cover, designing corresponding conical ring blanks according to the structural size of each ring segment, forming the conical ring blanks into ring segments, sequentially splicing and fixing the bottom cover and the plurality of ring segments on a ring seam welding tool, respectively welding the butt joint areas of two adjacent ring segments along the ring direction, and welding the butt joint area of one ring segment tail end positioned at the top and the bottom cover along the ring direction to obtain the large box bottom. The invention has the advantages of good weld performance, high production efficiency and low manufacturing cost.

Inventors

  • FAN XIAOBO
  • YUAN SHIJIAN

Assignees

  • 大连理工大学

Dates

Publication Date
20260512
Application Date
20260413

Claims (9)

  1. 1. The large-scale box bottom forming method is characterized in that according to the structural design of an integral ring section, a flat welding blank is formed into the integral ring section and then is subjected to ring welding to form the large-scale box bottom, and the method comprises the following steps: S1, designing a large box bottom into a bottom cover and a plurality of ring section structures which are integrally formed; S2, designing a flat circular ring blank according to the structural size of the bottom cover, and forming the flat circular ring blank into the bottom cover; s3, designing a corresponding conical ring blank according to the structural size of each ring segment, and forming the conical ring blank into a ring segment; S4, sequentially splicing, installing and fixing the bottom cover and the plurality of ring segments on a ring seam welding tool, respectively welding the butt joint areas of two adjacent ring segments in the ring direction, and welding the tail end of one ring segment positioned at the top with the butt joint area of the bottom cover in the ring direction to obtain a large box bottom; The bottom cover is integrally formed by adopting a flat ring blank through a drawing or bulging process, the flat ring blank is an integral or flat splice welded round blank, and the ring section is integrally formed by adopting a conical ring blank through a bulging, flaring or necking process.
  2. 2. The method for forming a large bottom of a box according to claim 1, wherein the conical ring blank comprises a plurality of arc-shaped blanks which are connected end to end in sequence, the conical ring blank is formed by fixedly welding a flat plate rolled cone, and welding seams of the welding seams are reinforced in accordance with a base material during forming.
  3. 3. A large bottom forming method according to claim 1, wherein the profile of the abutting area between the adjacent ring segments or the ring segments and the bottom cover is designed as a transition profile, and the transition profile is locally bulging or rolling to an actual profile after welding along the circumferential direction.
  4. 4. The method for forming a large bottom of a tank as set forth in claim 3, wherein the radial arc length of the transition profile is 0.5% -25% smaller than the radial arc length of the actual profile.
  5. 5. The method for forming a large bottom according to claim 1, wherein the temperature in the forming process is normal temperature to-196 ℃.
  6. 6. The method of forming a large bottom of a container according to claim 1, wherein the bottom cover and the ring section are made of aluminum alloy, solid solution stainless steel or hard stainless steel.
  7. 7. The method of forming a large bottom of a container according to claim 1, wherein the welding process is one of friction stir welding, laser welding, argon arc welding, and electron beam welding.
  8. 8.A large box bottom manufactured based on the large box bottom forming method according to any one of claims 1-7 is characterized by comprising a bottom cover, wherein the bottom cover is a spherical or ellipsoidal cone bottom, the projection of the bottom cover on a virtual horizontal plane is of a circular structure, at least one ring section, when one ring section is arranged, the outer side edge of the ring section is fixedly and hermetically connected with the side edge of the bottom cover, when a plurality of ring sections are arranged, a plurality of ring sections are sequentially overlapped, two adjacent ring sections are fixedly sealed, and the outer side edge of one ring section positioned at the top is fixedly and hermetically connected with the side edge of the bottom cover.
  9. 9. The large bottom of claim 8, wherein the bottom cover and the ring segments are integrally formed.

Description

Large box bottom and forming method thereof Technical Field The invention relates to the technical field of rocket structure manufacturing, in particular to a large-sized box bottom and a forming method thereof. Background In the aerospace field, rocket body diameters of rockets continue to increase. The dry weight ratio of the fuel storage tank is 80% as the main body structure of the rocket, the fuel storage tank is generally composed of front and rear tank bottoms, a cylinder section, a short shell and other parts, not only bears the fuel storage function, but also needs to bear complex loads such as internal pressure, shaft pressure, vibration, impact and the like, and the operation reliability of the rocket is directly determined. The multiple increase in the diameter of the arrow presents challenges to the design and manufacture of the arrow structure, with the manufacture of large fuel tank bottoms being one of the core challenges. The large-sized box bottom is of a semi-ellipsoidal curved surface structure, has the characteristics of super-large diameter and super-thin wall thickness, the wall thickness of the 5 m-level aluminum alloy box bottom is only a few millimeters, the thickness of the 10 m-level stainless steel box bottom is less than 4mm, the defects of instability and wrinkling easily occur in the whole forming process, and meanwhile, the characteristics of arrow-shaped structural materials such as poor formability and deep structural cavities further increase the risk of cracking in the forming process. As shown in fig. 1, the manufacturing route of the existing large-sized box bottom generally adopts a mode of respectively forming a plurality of circular melon petals and top cover melon petals and then welding the circular melon petals and the top cover melon petals together. The manufacturing method has the inherent defects that firstly, the number of melon petals is large, the assembly welding period is long, the manufacturing of a box bottom can be completed usually in tens of days, secondly, the welding is carried out after the forming, the performance of a welding line is greatly lost, the deformation and weight increase problems are easily generated in the welding process, thirdly, the number of the welding lines is large, the reliability of the box bottom structure is reduced, and huge pressure is brought to the welding line evaluation work of the reusable rocket, so that the development requirements of low cost, high efficiency and high reliability of the rocket are difficult to meet. Therefore, there is a need to design a technical scheme with good weld performance, high production efficiency and low manufacturing cost. Disclosure of Invention The invention aims to provide a large-sized box bottom and a forming method thereof, which are used for solving the problems of the prior art, and have the advantages of good weld joint performance, high production efficiency and low manufacturing cost. In order to achieve the above object, the present invention provides the following solutions: The invention provides a large-scale box bottom forming method, which is characterized in that according to the structural design of an integral ring section, a flat plate welding blank is formed into the integral ring section and then is subjected to ring welding to form the large-scale box bottom, and the method comprises the following steps: S1, designing a large box bottom into a bottom cover and a plurality of ring section structures; S2, designing a flat circular ring blank according to the structural size of the bottom cover, and forming the flat circular ring blank into the bottom cover; s3, designing a corresponding conical ring blank according to the structural size of each ring segment, and forming the conical ring blank into a ring segment; S4, sequentially splicing, installing and fixing the bottom cover and the plurality of ring segments on a ring seam welding tool, respectively welding the butt joint areas of two adjacent ring segments in the ring direction, and welding the tail end of one ring segment positioned at the top with the butt joint area of the bottom cover in the ring direction to obtain the large box bottom. In one embodiment, the bottom cover is integrally formed by adopting a flat circular ring blank through a drawing or bulging process, the flat circular ring blank is an integral circular blank or a circular blank formed by splicing and welding a plurality of strip-shaped blanks, and the splice welding seam and the base material are reinforced in a consistent manner during forming. In one embodiment, the ring section is integrally formed by adopting a conical ring blank through bulging, flaring or necking processes, the conical ring blank comprises a plurality of arc-shaped blanks which are connected end to end in sequence, the conical ring blank is fixedly spliced and welded into the conical ring blank after a flat plate is coiled, and the spliced and welded welding