Thin-wall titanium special-shaped flat can shell forming process

Abstract

The invention discloses a titanium thin-wall special-shaped flat can shell forming process. The cross section structure of a titanium thin-wall special-shaped flat can shell comprises a lower large arc surface, two small arc surfaces and a horizontal surface, wherein the two small arc surfaces are connected with the lower large arc surface and are symmetrically and vertically connected on two sides, and the horizontal surface is horizontally welded and connected with the upper edges of the two symmetrical side small arc surfaces. The forming process comprises the following manufacturing procedures of firstly pressing two small arc surfaces on the side edge, then rolling a large arc surface at the bottom, splicing two upper horizontal half planes together to form the same plane at the upper part, then tack welding, then welding and forming, and finally carrying out the operation procedures of heating, correcting, heat treatment, annealing and the like. The method comprises the steps of pressing, rolling, tack welding, welding, heating, sizing, heat treatment and sizing. By adopting the forming process, the flatness of the welding seam of the titanium thin-wall special-shaped flat can shell is effectively improved, the welding stress and the welding deformation are eliminated, and the overall processing and manufacturing quality of the titanium flat can shell is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of titanium irregular flat can shell forming technology for thin-walled structures, and particularly to a titanium thin-walled irregular flat can shell forming process. Background Technology

[0002] Titanium is used in many production fields due to its light weight, high strength and high corrosion resistance, such as aviation, marine and aerospace parts manufacturing, chemical equipment and parts production, and also widely used in the medical field due to its unique biological properties.

[0003] In the manufacturing and processing field, due to usage requirements, titanium thin-walled flat cans with irregular structures are manufactured. Their cross-sectional structure is similar to a semi-ellipse, with a flat top and comprising two small arcs on both sides and a large arc at the bottom. This type of flat can is typically formed by separately pressing or rolling the large arc at the bottom and the two small arcs on both sides, welding the two small vertical arcs to the ends of the bottom arc, and then welding a horizontal plate between the upper edges of the two small arcs. Finally, the finished product is formed by grinding the multiple welds.

[0004] In the current manufacturing process, firstly, the large number of scattered parts increases the number of welds, resulting in inconsistent shapes of the finished products. Due to the presence and unevenness of welding stress, the thin-walled, irregularly shaped flat can shells experience significant welding deformation, forming outward and inward angular deformations along the transverse direction of the weld; and significant wavy deformation along the longitudinal direction of the weld. This results in poor forming quality of the thin-walled, irregularly shaped flat can shells, increasing the need for multiple subsequent finishing processes, while also increasing manufacturing costs and extending the production cycle. Secondly, because most of these thin-walled, irregularly shaped flat can shells are irregularly curved structures, effective support and connection cannot be achieved during welding, leading to excessive accumulation of errors between components. This, in turn, affects the final forming accuracy and shape, significantly reducing the overall quality of the product. Furthermore, the increased number of welds also negatively impacts the long-term stability and safety of the product. Summary of the Invention

[0005] To address the aforementioned problems, this invention aims to provide a forming process for a thin-walled, irregularly shaped flat can shell made of titanium. The cross-sectional structure of the thin-walled titanium irregularly shaped flat can shell includes: a lower large arc surface, two smaller arc surfaces symmetrically connected vertically to the lower large arc surface, and an upper horizontal surface horizontally welded to the upper surface of the two symmetrical smaller arc surfaces. Through forming processes such as pressing, rolling, spot welding, welding, and heat treatment for shaping, the titanium flat blank is prepared into a one-piece thin-walled, irregularly shaped flat can shell, reducing weld seams, effectively ensuring the flatness and structural dimensions of the weld seams, eliminating welding stress, and greatly improving the overall manufacturing quality of the titanium flat can shell.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a forming process for a titanium thin-walled irregularly shaped flat can shell, wherein the thin-walled irregularly shaped flat can shell is composed of a large arc surface at the bottom, small arc surfaces on both sides, and a horizontal surface at the top. The forming process includes the following steps: S1. Using a mold that matches the inner and outer arc surfaces of the small arc surface, the two ends of the flat blank for forming the thin-walled irregular flat can shell are pressed into symmetrical small arc surfaces by external force of a press. S2. The middle part of the flat blank with two small arc surfaces on both sides is placed on a rolling machine and rolled to form the large arc surface. During the rolling of the large arc surface to reach the finished size, the straight edges of the outer small planes connected to the two symmetrical small arc surfaces are aligned to form the horizontal surface. S3. Spot weld the straight edge joint of the outer end small plane of the two symmetrical small arc surfaces, and then weld to form the integral weld and horizontal surface, and form a thin-walled irregular flat can shell. S4. Using a shaping fixture that matches the inner cavity size of the thin-walled irregular flat can shell, insert it into the inner cavity of the thin-walled irregular flat can shell to provide internal support and relative force reinforcement, and then place the whole in a heating furnace for annealing and heat shaping treatment.

[0007] Preferably, the alignment fixture is a segmented, detachable structure, comprising a left half and a right half.

[0008] Preferably, the alignment fixture is used as a reference to cut the left and right halves of the body into wedge-shaped mating structures at an angle of 5°~15°.

[0009] Specifically, the process of assembling the alignment fixture in step S4 is as follows: first, the entire left half is inserted into one side of the inner cavity of the thin-walled irregular flat can shell, then the small end of the right half is inserted from the small end of the left half, and then external forces are applied simultaneously from the large ends of the left half and the right half to make the outer walls of the left half and the right half gradually adhere to the inner wall of the flat can shell.

[0010] Specifically, the annealing heat straightening process in step S4 is as follows: the thin-walled irregular flat can shells equipped with straightening fixtures are stacked one on top of the other, and the horizontal surfaces of the upper and lower thin-walled irregular flat can shells are placed together, and then placed into a box-type heating furnace.

[0011] Specifically, the conditions for the annealing heat straightening process in step S4 are as follows: (a) Heat treatment method: electric furnace heating; (b) The furnace is filled with a protective gas: argon; (c) Temperature of the flat can shell entering the furnace: ≤150℃; (d) Heating rate: ≤150℃ / hour; (e) Annealing heating and holding temperature: 650±10℃; (f) Insulation time: 1.5 hours; (g) Cooling method: in-furnace cooling; (h) Exit temperature: ≤150℃.

[0012] The beneficial effects of this invention are as follows: This process, through steps such as pressing, rolling, spot welding, welding, and heating annealing, as well as shaping and finishing, produces a flat can shell with a high forming precision, forming an integral structure. This forming process improves the flatness of the weld seams of this titanium thin-walled irregularly shaped flat can shell, eliminates welding stress, reduces weld seams, and improves the overall manufacturing quality of this thin-walled irregularly shaped flat can shell. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the titanium thin-walled irregularly shaped flat can shell of the present invention.

[0014] Figure 2 This is a diagram illustrating the structure of each part of the flat can shell of the present invention.

[0015] Figure 3 This is a structural diagram of the flat plate blank for the flat can shell of the present invention.

[0016] Figure 4 This is a schematic diagram of the pressing and forming of the first small arc surface of the flat can shell of the present invention.

[0017] Figure 5 This is a schematic diagram of the pressing and forming of the second small arc surface of the flat can shell according to the present invention.

[0018] Figure 6 This is a schematic diagram of a plate rolling machine for forming a large circular arc of a flat can shell according to the present invention.

[0019] Figure 7 This is a schematic diagram of material placement during the large arc forming and rolling of the flat can shell according to the present invention.

[0020] Figure 8 This is a schematic diagram of the large arc forming and upper horizontal top surface forming of the flat can shell of the present invention.

[0021] Figure 9 This is a schematic diagram showing the deformation of the transverse outward convex corner of the weld seam during the original welding of the flat can shell of the present invention.

[0022] Figure 10 This is a schematic diagram showing the transverse concave corner deformation of the weld seam during the original welding of the flat can shell of the present invention.

[0023] Figure 11 This is a schematic diagram of the longitudinal wave deformation of the weld seam during the original welding of the flat can shell of the present invention.

[0024] Figure 12 This is a three-dimensional view of the calibration fixture of the present invention.

[0025] Figure 13 This is a three-dimensional view of the tooling separation of the present invention.

[0026] Figure 14 This is a diagram showing the installation method of the calibration fixture of the present invention.

[0027] Figure 15 This is a three-dimensional schematic diagram of the flat can shell placed with two planes touching each other before heat treatment according to the present invention.

[0028] Figure 16 This is a schematic diagram showing the placement of the box-type heating furnace and the flat can shell for heat straightening according to the present invention.

[0029] Figure 17 This is a schematic diagram of the heat treatment process for heating and reshaping the flat can shell of the present invention. Detailed Implementation

[0030] To enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0031] See attached document Figures 1-17 The diagram illustrates a forming process for a thin-walled, irregularly shaped flat can shell 10 made of titanium. The shell 10 is composed of a large arc surface 11 at the bottom, small arc surfaces 12 on both sides, and a horizontal surface 13 at the top. Figure 1 and Figure 2 The structure shown has an irregular cross-section with a large area and a small wall thickness. The shell is preferably made of industrial pure titanium, which has low density, high strength, and excellent corrosion resistance.

[0032] The thin-walled, irregularly shaped flat can shell 10 is formed using a flat blank 100 made of industrial pure titanium metal, which has low density, high strength, and excellent corrosion resistance. Figure 3 As shown in the figure, the part marked 110 is the formed large arc surface 11, the parts marked 120 on both sides are the formed small arc surfaces 12, and the parts marked 130 on both sides are the horizontal surfaces 13 formed by welding after butt joint. The forming process is: pressing - rolling - spot welding - welding - annealing and shaping. The specific forming process includes the following steps: S1, such as Figure 3 , Figure 4 and Figure 5 As shown, the forming operation of the small arc surface 12 is as follows: using a mold 20 (including a punch 21 and a die 22) that matches the inner and outer arc surfaces of the small arc surface 12, the two ends of the flat blank 100 that forms the thin-walled irregular flat can shell 10 are pressed into the symmetrical small arc surface 12 by the external force of a press.

[0033] S2, such as Figure 6 , Figure 7 and Figure 8 As shown, the forming operation of the large arc surface 11 is as follows: the middle part 110 of the flat blank 100, which has two small arc surfaces 12 on both sides, is placed on the rolling machine 30 for rolling. The 110 marked part on the flat blank 100 is placed on the two lower rollers 33 of the rolling machine 30. The upper roller 31 is pressed down by turning the screw 32 on the rolling machine 30 downward. The rolling machine 30 is started simultaneously. When the upper roller 31 and the lower roller 33 rotate at the same time, the flat blank 110 between the two symmetrical small arc surfaces 12 is rolled to form the large arc surface 11.

[0034] S3. The forming operation of the horizontal surface 13 is as follows: while the lower large arc 11 is rolled to gradually reach the finished size, the straight edges of the two small planes 130 marked with the two symmetrical side small arc surfaces 12 are gradually connected to each other to form the overall horizontal surface 13. The two small planes marked with the two 130 are then spot-welded together to form the overall horizontal surface 13 and a connecting weld 14 is formed (preferably, the two upper horizontal surfaces are welded together by tungsten inert gas welding (TIG) to form a fully penetrated weld). At the same time, a semi-finished thin-walled irregular flat can shell 10 is formed.

[0035] After welding the thin-walled, irregularly shaped flat can shell 10 to the horizontal plane 13, welding deformation may occur due to the presence of welding stress, resulting in angular deformation along the transverse direction of the weld (such as...). Figure 9 and Figure 10 (The welding deformation shown). Furthermore, due to the uneven welding stress, significant wavy deformation also occurs along the longitudinal direction of the weld (see attached image). Figure 11 As shown in the figure, the thin-walled irregular flat can shell 10 has poor forming quality, which increases the number of subsequent rework processes and also increases the manufacturing cost and production cycle. Therefore, the flat can shell 10 must be subjected to heat treatment for reshaping.

[0036] S4. When performing heat treatment to straighten the thin-walled, irregularly shaped flat can shell 10, the following method shall be used: Figure 12 and Figure 13 The shaping fixture 40 shown is fitted to the inner cavity of the thin-walled irregular flat can shell 10. After inserting it into the inner cavity of the thin-walled irregular flat can shell 10 to provide internal support and relative force, the whole is placed in a heating furnace for annealing and heat shaping treatment.

[0037] Because the thin-walled, irregularly shaped flat can shell 10 undergoes welding deformation after welding, it is not easy to smoothly insert the shaping fixture 40 into its inner cavity for support. Therefore, if Figure 13As shown, the straightening fixture 40 is manufactured as a segmented, detachable structure, including a left half 41 and a right half 42. Preferably, the straightening fixture 40 is cut at an angle of 5º~15º to form the left half 41 and right half 42 with a wedge-shaped fit structure, with its upper and lower center lines as a reference.

[0038] The specific installation procedure is as follows: Figure 14 As shown, firstly, the left half 41 of the straightening fixture 40 is inserted into one side of the inner cavity of the welded thin-walled irregular flat can shell 10. Then, the right half 42 is inserted from the small end of the left half 41 of the straightening fixture 40. Then, external forces are applied simultaneously from the large ends of the left half 41 and the right half 42 of the straightening fixture 40 to make the outer wall of the straightening fixture 40 gradually adhere to the inner wall of the thin-walled irregular flat can shell 10, thereby realizing the smooth insertion of the straightening fixture 40 into the inner cavity of the thin-walled irregular flat can shell 10 with welding deformation and achieving the supporting function.

[0039] like Figure 15 and Figure 16 As shown, the thin-walled irregularly shaped flat can shell 10 undergoes a heating and reshaping heat treatment using a box-type electric heating furnace 50. The furnace chamber is large enough to completely house the thin-walled irregularly shaped flat can shell 10 with the reshaping fixture 40 without touching the inner wall of the furnace chamber. When the thin-walled irregularly shaped flat can shell 10 is placed into the furnace chamber of the box-type heating furnace 50, with the horizontal surfaces 13 of the supported thin-walled irregularly shaped flat can shell 10 with the reshaping fixture 40 placed side by side and aligned. The furnace chamber is then sealed, and the furnace chamber of the box-type electric heating furnace 50 is filled with inert gas—argon—to replace the air in the furnace chamber and prevent oxidation of the surface of the thin-walled irregularly shaped flat can shell 10.

[0040] Because the horizontal surfaces 13 of the upper and lower thin-walled, irregularly shaped flat can shells 10 are in contact with each other, therefore, as Figure 15-16 As shown, the large arc surface 11 of the thin-walled, irregularly shaped flat can shell 10 at the bottom contacts the bottom surface of the furnace. To prevent tipping, pads can be used to support the large arc surface 11 on both sides to prevent tilting.

[0041] like Figure 17 The figure shown is a heat treatment process curve for heating and shaping the thin-walled irregular-shaped flat can shell 10. The heat treatment process specifications for heating and shaping the thin-walled irregular-shaped flat can shell 10 are as follows: (a) Heat treatment type: Post-weld stress-relief annealing; (b) Heat treatment method: electric furnace heating; (c) Furnace entry temperature of thin-walled irregularly shaped flat can shell 10; (d) The furnace is filled with a protective gas: argon (Ar); (e) Furnace entry temperature: ≤150℃; (f) Heating rate: ≤150℃ / hour; (g) Insulation temperature: 650±10℃; (h) Insulation time: 1.5 hours; (I) Cooling method: In-furnace cooling; (j) Exit temperature: ≤150℃.

[0042] During the heat treatment and heat preservation process of the thin-walled irregular-shaped flat can shell 10, the welding stress in the weld of the thin-walled irregular-shaped flat can shell 10 is gradually and completely eliminated. Utilizing the self-weight and supporting force of the thin-walled irregular-shaped flat can shell 10 and the shaping fixture 40, the inner cavity of the thin-walled irregular-shaped flat can shell 10 is made to completely fit and conform to the outer wall of the shaping fixture 40. This also reduces the lateral deformation of the weld of the thin-walled irregular-shaped flat can shell 10 (such as...). Figure 9 , Figure 10 (as shown) and longitudinal wave deformation (as shown) Figure 11 (As shown) completely disappears, allowing the thin-walled irregularly shaped flat can shell 10 to achieve the desired shape and size.

[0043] After the thin-walled irregular-shaped flat can shell 10 is heated and shaped according to the heat treatment process specifications, it is cooled in the furnace chamber of the box-type heating furnace 50. When the temperature drops below 150°C, the thin-walled irregular-shaped flat can shell 10 with the shaping fixture 40 is taken out and the shaping fixture 40 inside the thin-walled irregular-shaped flat can shell 10 is removed, thus completing the heating and shaping operation of the thin-walled irregular-shaped flat can shell 10.

[0044] The principle of this invention is as follows: a flat blank 100 is prepared into a structure with a large bottom arc surface 11 and symmetrical side small arc surfaces 12 by pressing and rolling, and the horizontal surface 13 is in a butt joint state. Then, a thin-walled irregular flat can shell 10 is formed by tack welding and welding. Finally, the thin-walled irregular flat can shell 10 is subjected to heat treatment of heating, shaping and annealing to achieve the required shape and size requirements and eliminate welding stress and welding deformation.

[0045] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Various changes and modifications can be made to the present invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A process for forming a titanium thin-walled, shaped, flat can shell, characterized in that, The thin-wall special-shaped flat can shell (10) is composed of a large circular surface (11) at the bottom, two small circular surfaces (12) at the sides and a horizontal surface (13) at the top, and the forming process comprises the following steps: S1, a die (20) matched with the inner and outer wall arc surfaces of the small circular surfaces (12) is used to press the two ends of the flat blank (100) of the thin-wall special-shaped flat can shell (10) inward at the corresponding position (120) of the equal length, so that the two small circular surfaces (12) are formed symmetrically; S2, the middle part (110) of the flat blank (100) with the two small circular surfaces (12) formed by pressing on both sides is placed on a plate rolling machine (30) to be rolled to form the large circular surface (11), and in the process of rolling the large circular surface (11) to gradually reach the finished product size, the straight edges of the outer end planes (130) connected with the two small circular surfaces (12) on the two sides are butted against each other to form the horizontal surface (13); S3, the two outer end planes (130) are fixed by spot welding at the positions where the straight edges of the two outer end planes (130) are butted against each other, and then welded to form a weld (14) and an integral horizontal surface (13), and a thin-wall special-shaped flat can shell (10) is formed; S4, a shape correcting tool (40) matched with the size of the inner cavity of the thin-wall special-shaped flat can shell (10) is used to support the inner cavity of the thin-wall special-shaped flat can shell (10) by being inserted into the inner cavity, and then the whole is placed in a heating furnace (50) for annealing and heat correction.

2. The process for forming a titanium thin-walled, shaped, flat can shell according to claim 1, wherein: The shape correcting tool (40) is a split detachable structure, comprising a left half part (41) and a right half part (42).

3. The process for forming a titanium thin-wall special-shaped can shell according to claim 2, characterized in that: The shape correcting tool (40) is cut into a wedge-shaped matching structure at an angle of 5º~15º based on the upper and lower center lines of the shape correcting tool (40).

4. The process for forming a titanium thin-wall special-shaped can shell according to claim 3, characterized in that, The process of assembling the shape correcting tool (40) in step S4 is as follows: first, the left half part (41) is assembled into the inner cavity of the thin-wall special-shaped flat can shell (10) on one side, then the right half part (42) is assembled into the inner cavity from the small end of the left half part (41), and then external force is applied to the large end of the left half part (41) and the right half part (42) at the same time, so that the outer wall of the left half part (41) and the right half part (42) gradually fits the inner wall of the flat can shell (10).

5. The process for forming a titanium thin-wall special-shaped can shell according to claim 4, characterized in that: The process of the annealing and heat correction in step S4 is as follows: the thin-wall special-shaped flat can shells (10) assembled with the shape correcting tool (40) are stacked up and down, the horizontal surfaces (13) of the upper and lower thin-wall special-shaped flat can shells (10) are matched, and then the stacked thin-wall special-shaped flat can shells (10) are assembled into a box-type heating furnace (50).

6. The process for forming a titanium thin-wall special-shaped can shell according to claim 5, characterized in that: The conditions of the annealing and heat correction in step S4 are as follows: (a) heat treatment method: electric furnace heating; (a) filling protective gas in the furnace: argon; (a) temperature of the flat can shell entering the furnace: ≤150℃; (a) heating rate: ≤150℃ / hour; (a) annealing and heating temperature: 650±10℃; (a) holding time: 1.5 hours; (a) cooling method: furnace cooling; (h) temperature of the flat can shell leaving the furnace: ≤150℃.

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