A reinforcing structure for a weld of a stainless steel tank

Abstract

The present application relates to a kind of weld reinforcement structure for stainless steel tank, belong to aerospace vehicle propellant tank structure technical field;First tank bottom, first short shell, barrel section, second short shell and second tank bottom;Wherein, first tank bottom and second tank bottom are hemispherical shell structure;First short shell, second short shell, barrel section are barrel section structure;First short shell, barrel section and second short shell are in turn horizontal coaxial butt joint;First tank bottom is coaxially installed at the axial outer end of first short shell;Second tank bottom is coaxially installed at the axial outer end of second short shell;The open end of first tank bottom is inserted into first short shell, and the outer wall of first tank bottom is butt joint with the inner wall of first short shell;The open end of second tank bottom is inserted into second short shell, and the outer wall of second tank bottom is butt joint with the inner wall of second short shell;The present application solves the problem that the welding performance of reinforcing material cannot be reinforced by partition thickness design, realizes the purposes such as high performance, low cost manufacturing of stainless steel tank.

Description

Technical Field

[0001] This invention belongs to the technical field of propellant tank structure for aerospace launch vehicles, and relates to a weld reinforcement structure for stainless steel tanks. Background Technology

[0002] The propellant tank is a key component of the launch vehicle's propulsion and structural systems, playing a crucial role in force transmission, shape maintenance, and propellant storage and delivery. It accounts for approximately 50-60% of the rocket's structural weight, thus requiring extremely high levels of lightweight design and reliability. Due to its large size, the tank cannot be formed as a single piece; a manufacturing process typically involves shaping it into sections and then welding them together. However, the welding process significantly degrades the properties of the base material, substantially weakening the tank's load-bearing capacity. Therefore, reinforcing the welded structure has always been a top priority in propellant tank design.

[0003] For aluminum alloy storage tanks, the performance degradation caused by welding is generally compensated for by locally thickening the weld seams and their heat-affected zones. This is mainly because aluminum alloys have relatively low hardness, are easier to machine, and their service performance can be uniformly controlled through subsequent heat treatment. Therefore, for aluminum alloy storage tanks, the weld seams and their heat-affected zones can be designed to be thicker, while the non-welded areas can be designed to be thinner, thus achieving the design concept of compensating for strength differences with thickness differences.

[0004] In recent years, stainless steel has shown great promise for applications in reusable, low-cost, and rapidly manufactured cryogenic propellant tanks due to its advantages such as low-temperature toughness, high-temperature resistance, processability, and low cost. However, welding stainless steel results in significant performance degradation due to martensite degradation to austenite and dislocation annihilation, leading to substantial differences in mechanical properties between the weld and the base material, posing a severe challenge to the service life of the components. Furthermore, the high hardness of stainless steel makes machining extremely difficult, rendering traditional thick-plate machining methods for aluminum alloys unsuitable and preventing the use of zoned thickness designs to compensate for the strength differences between the weld and the base material. Therefore, the development of new stainless steel weld reinforcement structures is urgently needed.

[0005] In summary, there are some problems with the welding process for stainless steel storage tanks, mainly including the following:

[0006] (1) When stainless steel is formed and then welded, there is deformation martensite degradation and dislocation annihilation, which severely degrades the mechanical properties of the weld and greatly weakens the service performance of the component.

[0007] (2) Stainless steel has high hardness and is difficult to machine, so it is not possible to follow the technical route of forming aluminum alloys by thick plate and then machining them. Summary of the Invention

[0008] The technical problem solved by this invention is to overcome the shortcomings of the prior art and propose a weld reinforcement structure for stainless steel storage tanks. This solves the problem that the welding performance of the reinforcement material cannot be weakened by partition thickness design, thereby achieving the goals of high performance and low cost manufacturing of stainless steel storage tanks.

[0009] The solution of the present invention is:

[0010] A welded seam reinforcement structure for a stainless steel storage tank includes a first tank bottom, a first short shell, a cylindrical section, a second short shell, and a second tank bottom;

[0011] The first and second box bottoms are both hemispherical shell structures; the first short shell, the second short shell, and the cylindrical section are all cylindrical section structures; the first short shell, the cylindrical section, and the second short shell are sequentially and horizontally coaxially connected; the first box bottom is coaxially installed at the axial outer end of the first short shell; the second box bottom is coaxially installed at the axial outer end of the second short shell; the open end of the first box bottom extends into the first short shell, and the outer wall of the first box bottom is connected to the inner wall of the first short shell; the open end of the second box bottom extends into the second short shell, and the outer wall of the second box bottom is connected to the inner wall of the second short shell.

[0012] In the above-mentioned weld reinforcement structure for a stainless steel storage tank, both the first short shell and the second short shell include multiple stainless steel plates; the stainless steel plates are rectangular; the multiple stainless steel plates are spliced ​​together circumferentially and rolled into a ring structure; the splicing seams of the multiple stainless steel plates are welded.

[0013] In the above-mentioned welded seam reinforcement structure for a stainless steel storage tank, the cylindrical section is formed by rolling one or more stainless steel plates into a ring structure and welding them at the joints of the stainless steel plates.

[0014] In the aforementioned weld reinforcement structure for a stainless steel storage tank, the specific welding method at the joint of the stainless steel plates is as follows:

[0015] Step 1: Perform the first welding treatment at the joint of the stainless steel plates;

[0016] Step 2: Apply weld reinforcement patches to the joints of the stainless steel plates after the first weld.

[0017] Step 3: Perform a second welding process on the weld reinforcement plate.

[0018] In the above-mentioned weld reinforcement structure for a stainless steel storage tank, in step one, the first welding process is to directly weld the splice seam.

[0019] In the above-mentioned weld reinforcement structure for stainless steel storage tank, in step two, the weld reinforcement sheet is arranged along the axial direction, the weld reinforcement sheet is attached to the inner wall of two adjacent stainless steel plates, and the weld reinforcement sheet covers the splice seam.

[0020] In the above-mentioned weld reinforcement structure for stainless steel storage tanks, the weld reinforcement sheet is a double-wave-shaped sheet structure; the two waves are symmetrically arranged along the center line; the center line of the weld reinforcement sheet coincides with the splice seam.

[0021] In the aforementioned weld reinforcement structure for a stainless steel storage tank, the wave period 'a' of the weld reinforcement sheet is 98-102 mm; the distance 'b' from the trough to the center line is 24-26 mm; the distance 'c' from the crest to the trough is 99-101 mm; both the crest and trough are straight structures with the same width, and the width 'd' of the trough is 38-42 mm; the crest and trough are connected by a hypotenuse with an angle 'α' of 5°-7°; and the transition between the crest and hypotenuse, and between the trough and hypotenuse, is achieved through rounded corners with a radius 'r' of 9-11 mm.

[0022] In the above-mentioned weld reinforcement structure for a stainless steel storage tank, in step three, during the second welding, each wave of the weld reinforcement piece is welded to the corresponding stainless steel plate.

[0023] In the above-mentioned weld reinforcement structure for stainless steel storage tanks, during the second welding, only the beveled edge of the weld reinforcement piece is welded; TIG welding is used, and the width of each weld is 18-22mm.

[0024] The beneficial effects of this invention compared to the prior art are:

[0025] (1) In terms of design, this invention improves the structural strength and reliability. The weld reinforcement plate can effectively compensate for welding defects, eliminate the negative impact of the decline in mechanical properties after welding on the overall structural strength, and solve the problem of insufficient load-bearing capacity of the main structure.

[0026] (2) This invention avoids extensive machining of aluminum alloy components, shortens the manufacturing cycle, and effectively reduces the sensitivity of welding process. Even if the welding parameters fluctuate slightly, the reinforcement design can still provide sufficient safety margin.

[0027] (3) This invention reduces redundant materials while ensuring strength, achieving lightweight design. The weld reinforcement plate design only strengthens weak areas, balancing economy and mechanical performance. At the same time, it alleviates stress concentration, prevents crack initiation and propagation, improves fatigue life, and ensures the reusability of related structures. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall stainless steel storage tank of the present invention;

[0029] Figure 2 This is a schematic diagram showing the location of the weld reinforcement piece of the present invention;

[0030] Figure 3 This is a schematic diagram of the shape of the weld reinforcement piece of the present invention;

[0031] Figure 4 This is a schematic diagram showing the dimensions of the weld reinforcement plate of the present invention. Detailed Implementation

[0032] The present invention will be further described below with reference to the embodiments.

[0033] This invention provides a weld reinforcement structure for stainless steel storage tanks, which solves the problem that the weakening of the welding performance of the reinforcement material cannot be compensated by partition thickness design, and achieves the goals of high performance and low cost manufacturing of stainless steel storage tanks.

[0034] Stainless steel storage tanks use welded seam reinforcement structures, such as Figure 1 As shown, the structure specifically includes a first box bottom 1, a first short shell 2, a cylindrical section 3, a second short shell 4, and a second box bottom 5. Both the first box bottom 1 and the second box bottom 5 are hemispherical shell structures; the first short shell 2, the second short shell 4, and the cylindrical section 3 are all cylindrical section structures; the first short shell 2, the cylindrical section 3, and the second short shell 4 are sequentially and horizontally coaxially connected; the first box bottom 1 is coaxially installed at the axial outer end of the first short shell 2; the second box bottom 5 is coaxially installed at the axial outer end of the second short shell 4; the open end of the first box bottom 1 extends into the first short shell 2, and the outer wall of the first box bottom 1 is connected to the inner wall of the first short shell 2; the open end of the second box bottom 5 extends into the second short shell 4, and the outer wall of the second box bottom 5 is connected to the inner wall of the second short shell 4.

[0035] Both the first short shell 2 and the second short shell 4 consist of multiple stainless steel plates; the stainless steel plates are rectangular in structure; the multiple stainless steel plates are spliced ​​together circumferentially and rolled into a ring structure; the joints of the multiple stainless steel plates are welded. The cylindrical section 3 is made by rolling one or more stainless steel plates into a ring structure and welding them at the joints of the stainless steel plates.

[0036] The specific method for welding the joints of stainless steel plates is as follows:

[0037] Step 1: Perform the first welding treatment at the joint of the stainless steel plates; the first welding treatment is to weld the joint directly.

[0038] Step 2: Apply weld reinforcement patches to the joints of the stainless steel plates after the first welding.

[0039] like Figure 2 As shown, the weld reinforcement plate is arranged axially, attached to the inner wall of two adjacent stainless steel plates, and covers the joint. Figure 3 As shown, the weld reinforcement plate has a double-wave-shaped sheet structure; the two waves are symmetrically arranged along the center line; the center line of the weld reinforcement plate coincides with the splice seam.

[0040] like Figure 4As shown, the wave period a of the weld reinforcement plate is 98-102mm; the distance b from the trough to the center line is 24-26mm; the distance c from the crest to the trough is 99-101mm; both the crest and trough are straight structures with the same width, and the width d of the trough is 38-42mm; the crest and trough are connected by a hypotenuse with an angle α of 5°-7°; the transition between the crest and the hypotenuse, and between the trough and the hypotenuse, is achieved by a rounded corner with a radius r of 9-11mm.

[0041] Step 3: Perform a second welding process on the weld reinforcement plate.

[0042] During the second welding, each wave of the weld reinforcement sheet is welded to the corresponding stainless steel plate. Only the beveled edges of the weld reinforcement sheet are welded; TIG welding is used, and each weld is 18-22mm wide.

[0043] The cylindrical section is composed of stainless steel plates and weld reinforcement plates. Multiple stainless steel plates are joined together to form a single cylindrical section by longitudinal seam welding. Local weld reinforcement plates are installed at the longitudinal weld seams to control the weakening of the weldability of the stainless steel.

[0044] The core idea of ​​this invention is to add a weld reinforcement plate after the weld zone. The weld reinforcement plate is connected to the main structure by spot welding / lap welding, so that the weld reinforcement plate and the main structure together constitute the weld zone, thereby improving the structural load-bearing capacity.

[0045] In terms of design, this invention enhances structural strength and reliability. The weld reinforcement plate effectively compensates for welding defects, eliminates the negative impact of post-weld mechanical property degradation on the overall structural strength, and solves the problem of insufficient load-bearing capacity of the main structure.

[0046] In terms of manufacturing, this invention significantly improves the tolerance of the manufacturing process while maintaining economic efficiency. It avoids extensive machining of aluminum alloy components, shortens the manufacturing cycle, and effectively reduces the sensitivity of welding processes. Even with slight fluctuations in welding parameters, the reinforcement design still provides sufficient safety margin.

[0047] Furthermore, in terms of service performance, the balance between lightweighting and performance is optimized. Redundant materials are reduced to achieve lightweighting while maintaining strength. Reinforcement designs only strengthen weak areas, balancing economy and mechanical performance. Simultaneously, stress concentration is alleviated, crack initiation and propagation are prevented, fatigue life is improved, and the reusability of related structures is ensured.

[0048] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A weld reinforcement structure for a stainless steel storage tank, characterized in that: It includes the first box bottom (1), the first short shell (2), the cylindrical section (3), the second short shell (4), and the second box bottom (5); Among them, the first box bottom (1) and the second box bottom (5) are both hemispherical shell structures; the first short shell (2), the second short shell (4), and the cylindrical section (3) are all cylindrical section structures; the first short shell (2), the cylindrical section (3), and the second short shell (4) are connected horizontally and coaxially in sequence; the first box bottom (1) is coaxially installed at the axial outer end of the first short shell (2); the second box bottom (5) is coaxially installed at the axial outer end of the second short shell (4); the open end of the first box bottom (1) extends into the first short shell (2), and the outer wall of the first box bottom (1) is connected to the inner wall of the first short shell (2); the open end of the second box bottom (5) extends into the second short shell (4), and the outer wall of the second box bottom (5) is connected to the inner wall of the second short shell (4); The first short shell (2) and the second short shell (4) both include multiple stainless steel plates; the stainless steel plates are rectangular; the multiple stainless steel plates are spliced ​​together circumferentially and rolled into a ring structure; the splicing seams of the multiple stainless steel plates are welded. The cylindrical section (3) is made by rolling one or more stainless steel plates into a ring structure and welding them at the joints of the stainless steel plates. The specific method for welding the joints of stainless steel plates is as follows: Step 1: Perform the first welding treatment at the joint of the stainless steel plates; Step 2: Apply weld reinforcement patches to the joints of the stainless steel plates after the first weld. The weld reinforcement plate is set along the axial direction, and the weld reinforcement plate is attached to the inner wall of two adjacent stainless steel plates, and the weld reinforcement plate covers the splice seam. The weld reinforcement plate has a double-wave-shaped sheet structure; the two waves are symmetrically arranged along the center line; the center line of the weld reinforcement plate coincides with the splice seam; The wave period 'a' of the weld reinforcement plate is 98-102 mm; the distance 'b' from the trough to the centerline is 24-26 mm; the distance 'c' from the crest to the trough is 99-101 mm; both crests and troughs are straight structures with the same width, and the width 'd' of the trough is 38-42 mm; the crests and troughs are connected by a bevel, with a bevel angle of... The angle is 5°-7°; the transition between the crest and the hypotenuse, and between the trough and the hypotenuse, is achieved through rounded corners with a radius r of 9-11 mm. Step 3: Perform a second welding process on the weld reinforcement plate; During the second welding, each wave of the weld reinforcement sheet was welded to the corresponding stainless steel plate.

2. The weld reinforcement structure for a stainless steel storage tank according to claim 1, characterized in that: In step one, the first welding process involves directly welding the joint.

3. The weld reinforcement structure for a stainless steel storage tank according to claim 2, characterized in that: During the second welding, only the beveled edge of the weld reinforcement plate is welded; TIG welding is used, and the width of each weld is 18-22mm.

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