Device and method for forming inner wall of copper alloy contraction and expansion section for liquid rocket engine

Abstract

The invention discloses a device and method for forming the inner wall of a copper alloy contraction and expansion section for a liquid rocket engine, and the device for forming the inner wall of the contraction and expansion section comprises the following steps: clamping a blank once, and forming the blank twice by using a hydraulic machine to obtain the inner wall of the contraction and expansion section with machining allowance; and carrying out heat treatment and machining on the inner wall of the convergent-divergent section with the machining allowance to obtain the inner wall of the convergent-divergent section. The required raw materials are light in weight, the material utilization rate is high, the production period is short, the machining efficiency is high, and the manufacturing cost of the inner wall of the copper alloy contraction and expansion section for the liquid rocket engine can be greatly reduced.

Description

Technical Field

[0001] The invention relates to a device and method for forming the inner wall of a copper alloy expansion section for a liquid rocket engine, belonging to the technical field of sheet metal forming. Background Art

[0002] The structure of the inner wall of the copper alloy expansion section for liquid rocket engines is a curved generatrix conical rotating body with a cylindrical section. It is a large-sized thin-walled part. The existing process method is forging and then machining to remove the excess. This process method uses hot extrusion or billet making + die forging to forge and then machining to remove the excess.

[0003] This process method is used for the inner wall of the copper alloy expansion section of liquid rocket engines. Since hot extrusion and die forging require heating, the forming of the forging during heating will affect the forging structure. In order to ensure the uniformity of the forging structure and the stability of the mechanical properties, plastic deformation must occur in all parts. The inner wall of the expansion section is a large-sized thin-walled part with a complex shape and it is difficult to accurately control the deformation. In order to ensure the uniformity of the structure and the stability of the mechanical properties, the process allowance of the inner and outer surface thickness is 15mm to 25mm, the material utilization rate is low, and the processing cycle is long; the price of copper alloy is relatively high, and the forging forming requires a resistance furnace, which has high energy consumption, resulting in a high processing cost for the inner wall of the expansion section. Summary of the invention

[0004] The technical problem solved by the present invention is: in view of the problems of high manufacturing cost and high energy consumption of the inner wall of the copper alloy expansion section for liquid rocket engines in the current prior art, a device and method for forming the inner wall of the copper alloy expansion section for liquid rocket engines are proposed.

[0005] The present invention solves the above technical problems by the following technical solutions:

[0006] A copper alloy expansion section inner wall forming device for a liquid rocket engine, comprising a forming block, a positioning plate, a lower die, a stripping plate, and an upper die, wherein:

[0007] The lower die is fixedly arranged on the workbench of the hydraulic press, and the pressure block is forced by the main slide of the hydraulic press to press the blank tube material; the blank tube material used to prepare the inner wall of the expansion section is clamped in the lower die, and a positioning plate is arranged on the outer periphery of the blank tube material to assist in clamping. The forming pressure block moves to the top of the blank tube material to press the blank tube material during the first plastic deformation process; the upper die is pressed on the top of the blank tube material by the main slide of the hydraulic press during the second plastic deformation process; the stripping plate is arranged at the bottom inner side of the lower die, and is used to lift up the prepared formed blank after the second plastic deformation is completed.

[0008] The formed blank includes a straight tube section and a curved generatrix tapered tube section. In the first plastic deformation process, the blank tube material is pressed by a pressing block so that the blank tube material is partially pressed into the lower die, which is used to prepare the straight tube section of the inner wall of the expansion section; in the second plastic deformation process, the blank tube material is pressed by an upper die so that the blank tube material is completely pressed into the lower die; before the second plastic deformation process, the forming pressing block is moved away and the upper die is moved to the same position.

[0009] The overall structure of the formed blank is trumpet-shaped, the height of the straight section is not less than 1 / 4 of the inner wall height of the expansion section, and the ratio of the diameter of the straight section to the diameter of the curved generatrix cone section is not greater than 0.6.

[0010] The stripper plate is lifted up by the hydraulic cylinder of the hydraulic press workbench, and the stripper plate lifts the prepared formed blank from the lower die; the upper die and the positioning plate are moved out of their original positions before the hydraulic cylinder applies force, leaving only the formed blank in the lower die; the formed blank is subjected to heat treatment and machining to obtain the inner wall of the expansion section.

[0011] The blank tube material is selected according to the forming requirements of the inner wall of the expansion section to be prepared. The inner diameter of the blank tube material is between the inner diameter of the straight tube section and the inner diameter of the large end of the curved generatrix tapered tube section. The blank tube material is made of copper alloy material. During the first plastic deformation, the small end of the blank tube material is pressed by a pressing block to achieve plastic deformation to prepare the straight tube section. During the second plastic deformation, the large end of the blank tube material is pressed by an upper mold to achieve plastic deformation to prepare the curved generatrix tapered tube section.

[0012] A forming method implemented by a forming device for an inner wall of a copper alloy expansion section for a liquid rocket engine comprises:

[0013] Select the blank tube material according to the forming requirements of the inner wall of the expansion section, and clamp it into the lower die through the positioning plate;

[0014] The lower die is fastened on the workbench of the hydraulic press, and the main slide of the hydraulic press is controlled to apply force to the pressing block to perform the first forming process, so that the small end of the blank undergoes plastic deformation, and the forming of the straight tube section is completed;

[0015] The pressing block and the positioning plate are removed, and the upper die is forced by the main slide of the hydraulic press to perform the second forming process, so that the large end of the blank undergoes plastic deformation, and the forming of the curved generatrix cone section is completed;

[0016] The hydraulic cylinder under the hydraulic press workbench applies force to the stripper plate, and the stripper plate lifts up the plastically deformed blank to complete the stripping.

[0017] The successfully returned formed blank is heat treated and machined to obtain the inner wall of the expansion section.

[0018] The successfully returned formed blank is heat treated to eliminate stress. After the stress is eliminated, the formed blank is machined to achieve contour finishing. The machining includes finishing the inner surface and finishing the outer surface. The finishing of the inner surface and finishing the outer surface is to perform excess cutting on the inner surface and the outer surface to meet the contour requirements; the contours of the finished inner surface and the finished outer surface are both set to be no more than 0.2mm.

[0019] Before the formed blank is heat treated, lubricant is applied to the outer surface and the lower mold surface to ensure that there are no scratches on the surface of the formed blank, the surface of the upper mold, and the surface of the lower mold; the contour of the formed blank is determined by measuring the thickness of the formed blank along the generatrix, and calculating the allowance of the fine-machined contour surface based on the thickness data.

[0020] The forming blank is heat treated by annealing to eliminate the stress of the forming blank, the outer surface of the forming blank is preliminarily processed, a reference surface is processed on the outer surface of the forming blank, the forming blank is clamped with the reference surface, and the inner surface is finely processed. The forming blank is clamped with the inner surface after fine processing as the reference, and the outer surface is finely processed. After the machining is completed, the inner wall of the expansion section is obtained.

[0021] The advantages of the present invention compared with the prior art are:

[0022] (1) The present invention provides a device and method for forming the inner wall of a copper alloy expansion section for a liquid rocket engine. The blank is clamped once, and a hydraulic press is used to form the blank twice to obtain the inner wall of the expansion section with a processing allowance; the inner wall of the expansion section with a processing allowance is heat treated and machined to obtain the inner wall of the expansion section. The process method requires a small weight of raw materials, has a high material utilization rate, a short production cycle, and high processing efficiency, which can greatly reduce the manufacturing cost of the inner wall of the copper alloy expansion section for a liquid rocket engine;

[0023] (2) Compared with traditional processing methods, the present invention greatly reduces the raw material copper alloy required. At the same time, through the forging forming method of the present invention, the machining allowances on the inner and outer surfaces are greatly reduced, which can improve material utilization and shorten the processing cycle. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of the inner wall structure of the expansion section provided by the present invention;

[0025] Figure 2 A schematic diagram of the rough structure of the inner wall of the expansion section provided by the present invention;

[0026] Figure 3 A schematic diagram of the first forming preparation of the inner wall of the expansion section provided by the present invention;

[0027] Figure 4 A schematic diagram of the first forming completion of the inner wall of the expansion section provided by the present invention;

[0028] Figure 5 A schematic diagram of the second forming preparation of the inner wall of the expansion section provided by the present invention;

[0029] Figure 6 This is a schematic diagram of the completion of the second forming of the inner wall of the expansion section provided by the present invention. DETAILED DESCRIPTION

[0030] A device and method for forming the inner wall of a copper alloy expansion section for a liquid rocket engine. The device for forming the inner wall of the expansion section, by clamping a blank once, using a hydraulic press, forming the blank twice, to obtain the inner wall of the expansion section with a processing allowance; heat treatment and machining the inner wall of the expansion section with the processing allowance to obtain the inner wall of the expansion section. The invention requires a small weight of raw materials, a high material utilization rate, a short production cycle, and high processing efficiency, and can greatly reduce the manufacturing cost of the inner wall of the copper alloy expansion section for a liquid rocket engine.

[0031] The inner wall forming device of the expansion section includes a forming block, a positioning plate, a lower die, a stripping plate, and an upper die, wherein:

[0032] The lower die is fixedly arranged on the workbench of the hydraulic press, and the pressure block is forced by the main slide of the hydraulic press to press the blank tube material; the blank tube material used to prepare the inner wall of the expansion section is clamped in the lower die, and a positioning plate is arranged on the outer periphery of the blank tube material to assist in clamping. The forming pressure block moves to the top of the blank tube material to press the blank tube material during the first plastic deformation process; the upper die is pressed on the top of the blank tube material by the main slide of the hydraulic press during the second plastic deformation process; the stripping plate is arranged at the bottom inner side of the lower die, and is used to lift up the prepared formed blank after the second plastic deformation is completed.

[0033] The formed blank includes a straight tube section and a curved mother line tapered tube section. In the first plastic deformation process, the blank tube material is pressed by a pressing block so that the blank tube material is partially pressed into the lower die, which is used to prepare the straight tube section of the inner wall of the expansion section; in the second plastic deformation process, the blank tube material is pressed by an upper die so that the blank tube material is completely pressed into the lower die; before the second plastic deformation process, the forming pressing block is removed and the upper die is moved to the same position.

[0034] The stripper plate is lifted up by the hydraulic cylinder of the hydraulic press workbench, and the stripper plate lifts the prepared formed blank from the lower die; the upper die and the positioning plate are moved out of their original positions before the hydraulic cylinder applies force, leaving only the formed blank in the lower die; the formed blank is heat treated and machined to obtain the inner wall of the expansion section.

[0035] The blank tube material is selected according to the forming requirements of the inner wall of the expansion section to be prepared. The inner diameter of the blank tube material is between the inner diameter of the straight tube section and the inner diameter of the large end of the curved generatrix tapered tube section. The blank tube material is made of copper alloy. During the first plastic deformation, the small end of the blank tube material is pressed by a pressing block to achieve plastic deformation to prepare the straight tube section. During the second plastic deformation, the large end of the blank tube material is pressed by an upper mold to achieve plastic deformation to prepare the curved generatrix tapered tube section.

[0036] The forming method of the inner wall forming device of the copper alloy expansion section for liquid rocket engine is realized by the steps of:

[0037] Select the blank tube material according to the forming requirements of the inner wall of the expansion section, and clamp it into the lower die through the positioning plate;

[0038] The lower die is fastened on the workbench of the hydraulic press, and the main slide of the hydraulic press is controlled to apply force to the pressing block to perform the first forming process, so that the small end of the blank undergoes plastic deformation, and the forming of the straight tube section is completed;

[0039] The pressing block and the positioning plate are removed, and the upper die is forced by the main slide of the hydraulic press to perform the second forming process, so that the large end of the blank undergoes plastic deformation, and the forming of the curved generatrix cone section is completed;

[0040] The hydraulic cylinder under the hydraulic press workbench applies force to the stripper plate, and the stripper plate lifts up the plastically deformed blank to complete the stripping.

[0041] The successfully returned formed blank is heat treated and machined to obtain the inner wall of the expansion section.

[0042] The following is further described in conjunction with the accompanying drawings and preferred embodiments of the specification:

[0043] In the current embodiment, a method for forming the inner wall of a copper alloy expansion section of a liquid rocket engine is provided. Figure 1 As shown, the inner wall of the expansion section includes a straight section and a curved generatrix cone section connected to the straight section, comprising the following steps:

[0044] (1) preparing a blank, wherein the blank is a copper alloy tube material and is clamped in a lower die through a positioning plate;

[0045] like Figure 3 As shown, the blank 2 is clamped in the lower die 4 through the positioning plate 3.

[0046] (2) The lower die is fastened to the hydraulic press workbench, and the main slide of the hydraulic press applies force to the pressing block to perform the first forming, so that the small end of the blank undergoes plastic deformation, the forming of the straight cylinder section is completed, and a preliminary formed blank is obtained. The pressing block and the positioning plate are removed, and the main slide of the hydraulic press applies force to the upper die to perform the second forming, so that the large end of the preliminary formed blank undergoes plastic deformation, the forming of the curved generatrix tapered cylinder section is completed, and a fully formed blank is obtained. The hydraulic cylinder under the hydraulic press workbench applies force to the stripper plate, so that the stripper plate lifts the fully formed blank from the lower die, and then the fully formed blank is taken out;

[0047] like Figure 3 As shown, the inner wall of the expansion section is formed for the first time, the main slider of the hydraulic press applies force to the pressing block 1, and the pressing block 1 presses down the blank 2, and the small end of the blank 2 undergoes plastic deformation.

[0048] like Figure 4 As shown, the first forming of the inner wall of the expansion section is completed, and the blank 2 completes the forming of the straight tube section to become a preliminary formed blank 6.

[0049] like Figure 5 As shown, the inner wall of the expansion section is formed for the second time, the pressing block 1 and the positioning plate 3 are removed, and the preliminary formed blank 6 remains in the lower die 4. The main slide of the hydraulic press applies force to the upper die 7, and the upper die 7 presses down the preliminary formed blank 6, and the large end of the preliminary formed blank 6 undergoes plastic deformation.

[0050] like Figure 6 As shown, the second forming of the inner wall of the expansion section is completed, and the preliminary formed blank 6 completes the forming of the curved generatrix cone section to become a fully formed blank 8.

[0051] (3) The fully formed blank is subjected to heat treatment and machining to obtain the inner wall of the expansion section.

[0052] The present invention provides a method for forming the inner wall of a copper alloy expansion section for a liquid rocket engine. The blank is clamped once, and the blank is formed twice using a hydraulic press to obtain the inner wall of the expansion section with a processing allowance; the inner wall of the expansion section with the processing allowance is heat treated and machined to obtain the inner wall of the expansion section. The process method requires small raw materials, has high material utilization, short production cycle, and high processing efficiency, and can greatly reduce the manufacturing cost of the inner wall of the copper alloy expansion section for a liquid rocket engine.

[0053] In an optional embodiment, the inner wall of the expansion section is preferably: the inner diameter of the straight cylinder section is 100-400 mm, the height of the straight cylinder section is 50-150 mm, the inner diameter of the large end of the curved mother line cone cylinder section is 200-800 mm, and the overall height is 200-700 mm.

[0054] In an optional embodiment, the structure of the blank 2 in step (1) is a tube material, the inner diameter of the blank 2 is between the inner diameter of the straight tube section and the inner diameter of the large end of the curved mother line cone tube section, and the blank 2 is clamped in the lower mold 4 through a positioning plate 3.

[0055] In an optional embodiment, in the step (2), the lower die 4 is fastened to the hydraulic press workbench, the main slider of the hydraulic press applies force to the pressing block 1 to perform the first forming, so that the small end of the blank 2 undergoes plastic deformation, the forming of the straight cylinder section is completed, and the preliminary formed blank 6 is obtained, the pressing block 1 and the positioning plate 3 are removed, the main slider of the hydraulic press applies force to the upper die 7 to perform the second forming, so that the large end of the preliminary formed blank 6 undergoes plastic deformation, the forming of the curved generatrix tapered cylinder section is completed, and the fully formed blank 8 is obtained, the hydraulic cylinder below the hydraulic press workbench applies force to the stripping plate 5, so that the stripping plate 5 lifts the fully formed blank 8 from the lower die 4, and then the fully formed blank 8 is taken out;

[0056] In an optional embodiment, in step (3), the fully formed blank 8 is subjected to heat treatment and machining to obtain the inner wall of the expansion section.

[0057] The following are specific embodiments of the present invention:

[0058] Example 1

[0059] This embodiment provides a certain type of inner wall of the expansion section, the material of which is copper alloy QCr0.8, and the structure is as follows Figure 1 As shown, the inner wall of the expansion section includes a straight section and a conical section connected to the straight section, the inner diameter Φ1 of the straight section is 220 mm, the height of the straight section L1 is 80 mm, the inner diameter Φ2 of the large end of the curved generatrix conical section is 350 mm, and the overall height L2 is 290 mm. The forming method includes:

[0060] (1) preparing a blank 2, wherein the blank 2 is a copper alloy QCr0.8 tube material, and is clamped in a lower die 4 through a positioning plate 3;

[0061] (2) The main slide of the hydraulic press applies force to the pressing block 1, and the pressing block 1 presses down the blank 2, and the small end of the blank 2 undergoes plastic deformation;

[0062] (3) the pressing block 1 is pressed downward until the small end of the blank 2 contacts the stripping plate 5, so that the blank 2 completes the forming of the straight tube section and becomes a preliminary formed blank 6;

[0063] (4) The preliminary formed blank 6 remains in the lower die 4, the pressing block 1 and the positioning plate 3 are removed, and the main slide of the hydraulic press applies force to the upper die 7, and the upper die 7 presses down the preliminary formed blank 6, and the large end of the preliminary formed blank 6 undergoes plastic deformation;

[0064] (5) The upper die 7 is pressed downward until the outer surface of the large end of the preliminary formed blank 6 is in contact with the inner surface of the lower die 4, so that the preliminary formed blank 6 completes the forming of the curved generatrix cone section and becomes a fully formed blank 8;

[0065] (6) The upper die 7 is moved out, and the hydraulic cylinder under the hydraulic press worktable applies force to the stripper plate 5, so that the stripper plate 5 lifts the fully formed blank 8 from the lower die 4, and then takes out the fully formed blank 8;

[0066] (7) The fully formed blank 8 is subjected to heat treatment and machining to obtain the inner wall of the expansion section.

[0067] Compared with the deep drawing method, the thin-walled shell forming method provided in this embodiment has the following advantages:

[0068] (1) By using the method of the present invention, the weight of the raw material copper alloy QCr0.8 required for the inner wall of a certain type of expansion section described in Example 1 is 30 kg, while the weight of the raw material copper alloy QCr0.8 required by the forging forming method is 110 kg, saving 73% of the raw materials.

[0069] (2) By using the method of the present invention, the machining allowance of the inner and outer surfaces of the inner wall of a certain type of expansion section described in Example 1 is about 2 to 4 mm, while the machining allowance of the inner and outer surfaces by the forging forming method is 15 mm to 25 mm, thereby improving material utilization and shortening the processing cycle.

[0070] Example 2

[0071] This embodiment provides a certain type of inner wall of the expansion section, the material of which is copper alloy QCr0.8, and the structure is as follows Figure 1 As shown, the inner wall of the expansion section includes a straight section and a conical section connected to the straight section, the inner diameter Φ1 of the straight section is 100 mm, the height of the straight section L1 is 70 mm, the inner diameter Φ2 of the large end of the curved generatrix conical section is 180 mm, and the overall height L2 is 230 mm. The forming method includes:

[0072] (1) preparing a blank 2, wherein the blank 2 is a copper alloy QCr0.8 tube material, and is clamped in a lower die 4 through a positioning plate 3;

[0073] (2) The main slide of the hydraulic press applies force to the pressing block 1, and the pressing block 1 presses down the blank 2, and the small end of the blank 2 undergoes plastic deformation;

[0074] (3) the pressing block 1 is pressed downward until the small end of the blank 2 contacts the stripping plate 5, so that the blank 2 completes the forming of the straight tube section and becomes a preliminary formed blank 6;

[0075] (4) The preliminary formed blank 6 remains in the lower die 4, the pressing block 1 and the positioning plate 3 are removed, and the main slide of the hydraulic press applies force to the upper die 7, and the upper die 7 presses down the preliminary formed blank 6, and the large end of the preliminary formed blank 6 undergoes plastic deformation;

[0076] (5) The upper die 7 is pressed downward until the outer surface of the large end of the preliminary formed blank 6 is in contact with the inner surface of the lower die 4, so that the preliminary formed blank 6 completes the forming of the curved generatrix cone section and becomes a fully formed blank 8;

[0077] (6) The upper die 7 is moved out, and the hydraulic cylinder under the hydraulic press worktable applies force to the stripper plate 5, so that the stripper plate 5 lifts the fully formed blank 8 from the lower die 4, and then takes out the fully formed blank 8;

[0078] (7) The fully formed blank 8 is subjected to heat treatment and machining to obtain the inner wall of the expansion section.

[0079] Compared with the deep drawing method, the thin-walled shell forming method provided in this embodiment has the following advantages:

[0080] (1) By using the method of the present invention, the weight of the raw material copper alloy QCr0.8 required for the inner wall of a certain type of expansion section described in Example 1 is 10 kg, while the weight of the raw material copper alloy QCr0.8 required by the forging forming method is 70 kg, and the raw material is saved by 86%.

[0081] (2) By using the method of the present invention, the machining allowance of the inner and outer surfaces of the inner wall of a certain type of expansion section described in Example 1 is about 2 to 4 mm, while the machining allowance of the inner and outer surfaces by the forging forming method is 15 mm to 25 mm, thereby improving material utilization and shortening the processing cycle.

[0082] Furthermore, the inner wall of the copper alloy expansion section of the liquid rocket engine has a trumpet-shaped structure, with a straight cylinder section at the small end and a curved mother-line cone cylinder section at the large end. The height of the straight cylinder section is not less than 1 / 4 of the height of the inner wall of the expansion section, and the ratio of the small end diameter to the large end diameter is not greater than 0.6.

[0083] The inner wall of the copper alloy expansion section of the liquid rocket engine has a trumpet-shaped structure, with a straight cylinder section at the small end and a curved generatrix cone section at the large end. The height of the straight cylinder section is not less than 1 / 4 of the height of the inner wall of the expansion section, and the ratio of the small end diameter to the large end diameter is not greater than 0.6.

[0084] Before forming the inner wall of the expansion section, lubricant needs to be applied to the outer surface of the blank and the lower die surface. After the blank is formed, there are no scratches on the surface, and there are no scratches on the upper and lower die surfaces.

[0085] After the blank is formed, first check and confirm that the shape meets the requirements, then measure the thickness along the generatrix, and calculate the finishing allowance based on the thickness dimension.

[0086] After the blank is formed, it is first annealed to eliminate stress, and then the outer surface of the blank is preliminarily processed. A reference surface is processed on the outer surface of the blank, and then the blank is clamped with the above reference surface, and the inner surface is finely processed. Finally, the blank is clamped with the finely processed inner surface as the reference, and the outer surface is finely processed to obtain the inner wall of the expansion section.

[0087] Although the present invention has been disclosed as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

[0088] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. A copper alloy expansion section inner wall forming device for a liquid rocket engine, characterized in that: It includes a forming block, a positioning plate, a lower die, a stripper plate, and an upper die, wherein: The lower die is fixedly arranged on the workbench of the hydraulic press, and the pressure block is forced by the main slide of the hydraulic press to press the blank tube material; the blank tube material used to prepare the inner wall of the expansion section is clamped in the lower die, and a positioning plate is arranged on the outer periphery of the blank tube material to assist in clamping. The forming pressure block moves to the top of the blank tube material to press the blank tube material during the first plastic deformation process; the upper die is pressed on the top of the blank tube material by the main slide of the hydraulic press during the second plastic deformation process; the stripping plate is arranged at the bottom inner side of the lower die, and is used to lift up the prepared formed blank after the second plastic deformation is completed.

2. A copper alloy expansion section inner wall forming device for a liquid rocket engine according to claim 1, characterized in that: The formed blank includes a straight tube section and a curved generatrix tapered tube section. In the first plastic deformation process, the blank tube material is pressed by a pressing block so that the blank tube material is partially pressed into the lower die, which is used to prepare the straight tube section of the inner wall of the expansion section; in the second plastic deformation process, the blank tube material is pressed by an upper die so that the blank tube material is completely pressed into the lower die; before the second plastic deformation process, the forming pressing block is moved away and the upper die is moved to the same position.

3. The copper alloy expansion section inner wall forming device for a liquid rocket engine according to claim 1, characterized in that: The overall structure of the formed blank is trumpet-shaped, the height of the straight section is not less than 1 / 4 of the inner wall height of the expansion section, and the ratio of the diameter of the straight section to the diameter of the curved generatrix cone section is not greater than 0.

6.

4. A copper alloy expansion section inner wall forming device for a liquid rocket engine according to claim 1, characterized in that: The stripper plate is lifted up by the hydraulic cylinder of the hydraulic press workbench, and the stripper plate lifts the prepared formed blank from the lower die; the upper die and the positioning plate are moved out of their original positions before the hydraulic cylinder applies force, leaving only the formed blank in the lower die; the formed blank is subjected to heat treatment and machining to obtain the inner wall of the expansion section.

5. The copper alloy expansion section inner wall forming device for a liquid rocket engine according to claim 2, characterized in that: The blank tube material is selected according to the forming requirements of the inner wall of the expansion section to be prepared. The inner diameter of the blank tube material is between the inner diameter of the straight tube section and the inner diameter of the large end of the curved generatrix tapered tube section. The blank tube material is made of copper alloy material. During the first plastic deformation, the small end of the blank tube material is pressed by a pressing block to achieve plastic deformation to prepare the straight tube section. During the second plastic deformation, the large end of the blank tube material is pressed by an upper mold to achieve plastic deformation to prepare the curved generatrix tapered tube section.

6. A forming method implemented by the copper alloy expansion section inner wall forming device for liquid rocket engine according to claim 5, characterized in that include: Select the blank tube material according to the forming requirements of the inner wall of the expansion section, and clamp it into the lower die through the positioning plate; The lower die is fastened on the workbench of the hydraulic press, and the main slide of the hydraulic press is controlled to apply force to the pressing block to perform the first forming process, so that the small end of the blank undergoes plastic deformation, and the forming of the straight tube section is completed; The pressing block and the positioning plate are removed, and the upper die is forced by the main slide of the hydraulic press to perform the second forming process, so that the large end of the blank undergoes plastic deformation, and the forming of the curved generatrix cone section is completed; The hydraulic cylinder under the hydraulic press workbench applies force to the stripper plate, and the stripper plate lifts up the plastically deformed blank to complete the stripping. The successfully returned formed blank is heat treated and machined to obtain the inner wall of the expansion section.

7. The forming method according to claim 6, characterized in that: The successfully returned formed blank is heat treated to eliminate stress. After the stress is eliminated, the formed blank is machined to achieve contour finishing. The machining includes finishing the inner surface and finishing the outer surface. The finishing of the inner surface and finishing the outer surface is to perform excess cutting on the inner surface and the outer surface to meet the contour requirements; the contours of the finished inner surface and the finished outer surface are both set to be no more than 0.2mm.

8. The forming method according to claim 7, characterized in that: Before the formed blank is heat treated, lubricant is applied to the outer surface and the lower mold surface to ensure that there are no scratches on the surface of the formed blank, the surface of the upper mold, and the surface of the lower mold; the contour of the formed blank is determined by measuring the thickness of the formed blank along the generatrix, and calculating the allowance of the fine-machined contour surface based on the thickness data.

9. The forming method according to claim 6, characterized in that: The forming blank is heat treated by annealing to eliminate the stress of the forming blank, the outer surface of the forming blank is preliminarily processed, a reference surface is processed on the outer surface of the forming blank, the forming blank is clamped with the reference surface, and the inner surface is finely processed. The forming blank is clamped with the inner surface after fine processing as the reference, and the outer surface is finely processed. After the machining is completed, the inner wall of the expansion section is obtained.

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