A molding method for an injection unit assembly

Abstract

This invention discloses a molding method for an injector assembly, belonging to the field of aerospace injector technology. The method includes: S1, alloy powder preparation: drying CuCrZr alloy atomized powder and stainless steel alloy atomized powder separately in a vacuum drying oven, followed by ultrasonic vibration treatment; S2, injector assembly model design: designing an injector model; S3, setting printing parameters: importing the model into a laser selective melting device and setting parameters; S4, laser printing: obtaining the injector part through laser printing; S5, surface treatment: performing surface treatment on the injector part; S6, hot isostatic pressing: welding the injector part through hot isostatic pressing; S7, post-processing: machining and polishing the injector. This invention provides a molding method for an injector assembly that improves material utilization, ensures stable operation of the injector, and to a certain extent solves the problems of numerous weld joints, long manufacturing cycles, and complex processes in injector assembly manufacturing.

Description

Technical Field

[0001] This invention relates to the field of aerospace injector technology, and more specifically to a method for molding an injector assembly. Background Technology

[0002] An injector is a basic component used to uniformly inject and atomize fuel and oxidizer in a specific ratio for complete combustion. Its purpose is to ensure the complete combustion of the oxidizer and fuel. This component has a significant impact on the stability of a rocket engine and is considered a core component of the rocket engine.

[0003] Currently, there are two main methods for forming injector components. One is the traditional "casting-forging-machining-diffusion brazing" process, which has a long production cycle, low material utilization, and requires consideration of the reliability of various weld joints. The other is the emerging "3D printing-hot isostatic pressing" technology. However, the disadvantages of 3D printing for integrated components are obvious. Current technological limitations make this method suitable only for printing with the same material, not for applications requiring two or more materials. Moreover, existing 3D printing technology is not mature, and some key parts are not suitable for integrated design. The "split printing + welding" approach seems to be more popular among researchers and the current market. The injector component forming method described in this invention adopts the "split printing + welding" approach. Its innovation lies in the fact that after 3D printing, surface treatment and assembly are performed, followed directly by hot isostatic pressing diffusion welding, combining hot isostatic pressing and diffusion welding to shorten the process flow. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a molding method for an injector assembly. The technical solution of the present invention is: a molding method for an injector assembly, comprising the following steps:

[0005] S1. Alloy powder preparation:

[0006] The CuCrZr alloy atomized powder and the stainless steel alloy atomized powder were dried in a vacuum drying oven. After drying, they were cooled in the oven. The CuCrZr alloy atomized powder and the stainless steel alloy atomized powder were then subjected to ultrasonic vibration treatment. After ultrasonic vibration treatment, they were sieved through a 270-mesh sieve. The sieve-undersized material was collected to obtain pretreated CuCrZr alloy powder and pretreated stainless steel alloy powder.

[0007] S2. Injector component model design:

[0008] The lower chassis, upper chassis, and support structure of the injector are designed using modeling software. Then, the designed 3D models of the lower chassis, upper chassis, and support structure are combined to form a 3D solid model with scanning path information for each layer.

[0009] S3. Set printing parameters:

[0010] Import the three-dimensional solid model containing the scanning path information of each layer into the laser selective melting equipment, and set the printing parameters. The three-dimensional models of the upper and lower chassis are placed vertically with the larger end down and the smaller end up. At the same time, use the splitting software to divide the model into layers to form the laser processing scanning path of each layer.

[0011] S4, Laser Printing:

[0012] The pretreated CuCrZr alloy powder or pretreated stainless steel alloy powder is loaded into the laser selective melting equipment. After the base plate is placed, the scraper is installed. Then, the laser selective melting equipment is evacuated to a vacuum degree of about 3-5 Pa. Argon gas is then introduced as a protective gas. The powder is evenly spread to the laser processing area by the scraper, and the printing is performed layer by layer according to the printing parameters set in step S3 to obtain the lower chassis and upper chassis parts.

[0013] S5. Surface treatment:

[0014] Surface treatment is performed on the outer surfaces and internal channels of the aforementioned lower and upper chassis parts;

[0015] S6. Hot isostatic pressing treatment:

[0016] Assemble the lower and upper chassis, and assemble tooling molds on the outer sides of the lower and upper chassis. Attach the upper cover to the outer side of the upper chassis and the lower cover to the outer side of the lower chassis. Then, weld and seal the connection between the upper and lower covers. Install a vacuum tube below the lower cover and evacuate to a vacuum level of 1*10 through the vacuum tube. -2 -1*10 -3 Pa, and argon gas is introduced to maintain the pressure inside the casing at 3-5 Pa. Then, the injector assembly is subjected to hot isostatic diffusion welding using a hot isostatic press. After the hot isostatic diffusion welding is completed, the injector assembly with casing is obtained.

[0017] S7. Post-processing:

[0018] The aforementioned encased injector assembly is machined to remove the encasing, and then the surface of the injector assembly is polished. After polishing, a finished injector with a surface roughness Ra≤1.6μm is obtained.

[0019] Furthermore, in step S4, when the laser selective melting equipment prints the lower chassis of the injector, the powder filled in the laser selective melting equipment is pretreated CuCrZr alloy powder, and when the laser selective melting equipment prints the upper chassis of the injector, the powder filled in the laser selective melting equipment is pretreated stainless steel alloy powder.

[0020] Furthermore, in step S3, the printing parameters for printing the lower chassis are set as follows: the thickness of a single layer of pretreated CuCrZr alloy powder is 0.03-0.06 mm, the scanning spacing is 0.05-0.1 mm, the power is 400-460 W, and the scanning speed is 400-1600 mm / s.

[0021] Note: CuCrZr powder has good laser absorption rate, and the CuCrZr alloy printed under the above printing parameters has good density and fewer defects.

[0022] Furthermore, in step S3, the printing parameters for printing the upper chassis are set as follows: the thickness of a single layer of pre-treated stainless steel alloy powder is 0.05-0.12mm, the scanning spacing is 0.08-0.15mm, the XY shrinkage ratio is 1.115-1.12, the power is 300-400W, and the scanning speed is 400-1000mm / s.

[0023] Note: The stainless steel printed under the above printing parameters has good high temperature resistance, toughness, and corrosion resistance.

[0024] Furthermore, the surface treatment in step S5 includes one or more of liquid sandblasting, abrasive flow machining, electropolishing, and chemical cleaning.

[0025] Explanation: Liquid sandblasting uses high-pressure airflow to spray abrasive liquid onto the workpiece surface to remove impurities and oxide layers. Abrasive flow machining uses high-speed jets of abrasive particles to process the workpiece surface, improving surface quality and shape accuracy. Electrolytic polishing uses electrolysis to form an oxide layer on the workpiece surface, which is then removed by mechanical grinding to improve surface quality and shape accuracy. Chemical reagents use chemical reactions to form chemical substances on the workpiece surface, improving surface quality and shape accuracy.

[0026] Further, in step S6, the specific operation of the hot isostatic pressing treatment is as follows: during the hot isostatic diffusion welding, the diffusion welding temperature is 920-1000℃, the hot isostatic diffusion welding pressure is 10-50MPa, and the hot isostatic diffusion welding time is 2-8h.

[0027] Note: Hot isostatic pressure diffusion welding is performed under high temperature and uniform pressure, which makes the metal material in the weld area have the same strength as the base material and excellent toughness. Hot isostatic pressure diffusion welding can precisely control the shape and size of the weld joint, thereby reducing the deformation and defects of the weld joint and improving the quality and reliability of the weld joint.

[0028] Furthermore, in step S1, the drying time for CuCrZr alloy atomized powder and stainless steel alloy atomized powder is 4-10 hours, and the vacuum degree in the vacuum drying oven is 1*10⁻⁶.-3 -1*10 -4 Pa, the temperature inside the vacuum drying oven is 100-120℃.

[0029] Explanation: Drying reduces the moisture content of the raw material powder, preventing problems such as flowing, sticking, and collapsing during molding, thereby improving molding quality. Drying also makes the raw material powder more compact, reducing friction and resistance during molding, thus increasing molding speed. Moisture in the raw material powder evaporates during molding, which may lead to surface defects, porosity, and shrinkage. Drying can reduce the occurrence of these defects.

[0030] Furthermore, in step S1, the ultrasonic vibration treatment duration is 5-10 min, the ultrasonic vibration frequency is 35-40 kHz, and the ultrasonic vibration deviation angle is 8-10°.

[0031] Note: Ultrasonic vibration can make the molding quality more uniform and stable, thereby improving the molding quality and reliability.

[0032] Furthermore, the specific method for layer-by-layer printing in step S4 is as follows: after each laser scan is completed, the base plate descends by one layer until printing is completed. The laser scanning strategy has an angle of 45°-90° between the scanning lines of the N+1th layer and the Nth layer. After processing, the surface powder needs to be recovered using a powder suction tube, the printed structure is removed, the printed structure is cut and separated from the substrate using wire cutting, and the support is removed.

[0033] Note: Scanning using the powder spreading method described above will recover the surface powder after the part is processed. The part quality obtained by the above layer-by-layer printing method is superior.

[0034] Further, the finished injector in step S7 includes an upper chassis and a lower chassis. The outer wall of the lower chassis is fixedly connected to the inner wall of the upper chassis. The upper chassis includes an upper shell, and a fuel chamber is provided between the upper shell and the lower chassis. A connecting pipe is fixedly connected to the top of the upper shell. The lower chassis includes an injection panel, and an oxidant chamber is provided inside the injection panel. Multiple injection units are vertically fixedly connected inside the oxidant chamber. Each injection unit includes an inner cavity and an outer cavity. The upper end of the inner cavity is connected to the fuel chamber, and the lower end of the inner cavity is connected to the bottom of the injection panel. Multiple nozzles are circumferentially provided on the injection panel below the outer wall of the inner cavity. Multiple circular channels are circumferentially distributed on the outer wall of the outer cavity, and the circular channels are connected to the oxidant chamber. The lower end of the outer cavity is connected to the bottom of the injection panel through the nozzles. Multiple vertical channels are circumferentially distributed on the outer side of the injection panel, and the multiple vertical channels are connected to the interior of the oxidant chamber.

[0035] Explanation: Fuel is injected through the inner cavity, and oxidizer is injected through the nozzle. The fuel and oxidizer are evenly mixed below the injection panel, which helps to improve combustion efficiency. The flow rate and direction of liquid or gas can be controlled by adjusting the number, size and layout of the nozzles. The nozzle structure can increase the uniformity and stability of the injection.

[0036] Furthermore, the CuCrZr alloy atomized powder comprises the following components by mass ratio: Cr: 0.5-1.2%, Zr: 0.03-0.3%, Fe≤0.08%, Si≤0.1%, with the balance being Cu; the stainless steel alloy atomized powder comprises the following components by mass ratio: Ni: 10-14%, Cr: 16-18%, Mo: 2-3%, Si≤1.0%, Mn≤2.0%, P≤0.035%, S≤0.015%, C≤0.03%, with the balance being Fe.

[0037] Note: The composition of the CuCrZr alloy atomized powder and stainless steel alloy atomized powder is strictly controlled, and the prepared injector parts meet the requirements for strength, thermal conductivity, etc., which greatly improves the service life of the prepared injector components.

[0038] The beneficial effects of this invention are:

[0039] (1) The present invention provides a molding method for an injector assembly, specifically a beneficial combination of 3D printing and hot isostatic diffusion welding. The injector assembly obtained by this method not only eliminates the internal stress after 3D printing, but also ensures to a certain extent that after subsequent welding with other parts of the rocket engine, the weld joint of the injector assembly is not affected by other welding, and its performance is stable.

[0040] (2) The molding method of the injector assembly provided by the present invention can improve the material utilization rate by more than 80% compared with the traditional "casting-forging-machining-diffusion brazing" process, and solves the problems of multiple welding joints, long manufacturing cycle and complex process of injector assembly to a certain extent. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the structure of the injection assembly of the present invention;

[0042] Figure 2 This is a top view of the injection panel of the present invention;

[0043] Figure 3 This is a partial cross-sectional view of the injection unit of the present invention;

[0044] Figure 4 This is a simplified diagram of the injector with added sleeve according to the present invention.

[0045] Among them, 1-upper chassis, 2-lower chassis, 11-upper chassis shell, 12-fuel chamber, 13-connecting pipe, 21-injection panel, 22-oxidant chamber, 23-injection unit, 231-inner cavity, 232-outer cavity, 233-injection hole, 24-circular channel, 25-vertical channel. Detailed Implementation

[0046] Example 1:

[0047] A method for molding an injector assembly includes the following steps:

[0048] S1. Alloy powder preparation:

[0049] The CuCrZr alloy atomized powder and the stainless steel alloy atomized powder were dried in a vacuum drying oven. After drying, they were cooled in the oven. The CuCrZr alloy atomized powder and the stainless steel alloy atomized powder were then subjected to ultrasonic vibration treatment. After ultrasonic vibration treatment, they were sieved through a 270-mesh sieve. The sieve-undersized material was collected to obtain pretreated CuCrZr alloy powder and pretreated stainless steel alloy powder.

[0050] The drying time for CuCrZr alloy atomized powder and stainless steel alloy atomized powder was 4 hours, and the vacuum degree in the vacuum drying oven was 1*10. -3 Pa, the temperature inside the vacuum drying oven is 100℃;

[0051] The ultrasonic vibration treatment time is 5-10 min, the ultrasonic vibration frequency is 35 kHz, and the ultrasonic vibration deviation angle is 8°.

[0052] CuCrZr alloy atomized powder comprises the following components by mass ratio: Cr: 0.5%, Zr: 0.03%, Fe: 0.08%, Si: 0.1%, with the balance being Cu; stainless steel alloy atomized powder comprises the following components by mass ratio: Ni: 10%, Cr: 16%, Mo: 2%, Si: 1.0%, Mn: 2.0%, P: 0.035%, S: 0.015%, C: 0.03%, with the balance being Fe.

[0053] S2. Injector component model design:

[0054] The lower chassis 2 and upper chassis 1 of the injector and the support structure are designed using modeling software. Then, the designed three-dimensional models of the lower chassis 2, upper chassis 1 and support structure are combined to form a three-dimensional solid model with scanning path information for each layer.

[0055] S3. Set printing parameters:

[0056] Import the three-dimensional solid model containing the scanning path information of each layer into the laser selective melting equipment, and set the printing parameters. The three-dimensional models of the upper chassis 1 and the lower chassis 2 are placed vertically with the larger end down and the smaller end up. At the same time, use the splitting software to divide the model into layers to form the laser processing scanning path of each layer.

[0057] The printing parameters for printing the lower chassis 2 are set as follows: the thickness of a single layer of pre-treated CuCrZr alloy powder is 0.03mm, the scanning spacing is 0.05mm, the power is 400W, and the scanning speed is 400mm / s.

[0058] When printing the upper chassis 1, the printing parameters are set as follows: the thickness of a single layer of pre-treated stainless steel alloy powder is 0.05mm, the scanning interval is 0.08mm, the XY shrinkage ratio is 1.115, the power is 300W, and the scanning speed is 400mm / s.

[0059] S4, Laser Printing:

[0060] The pretreated CuCrZr alloy powder or pretreated stainless steel alloy powder is loaded into the laser selective melting equipment. After the base plate is placed, the scraper is installed. Then, the laser selective melting equipment is evacuated to a vacuum degree of about 3-5 Pa. Argon gas is then introduced as a protective gas. The powder is evenly spread to the laser processing area by the scraper, and the printing is performed layer by layer according to the printing parameters set in step S3 to obtain the lower base plate 2 and the upper base plate 1 parts.

[0061] When the laser selective melting equipment prints through the lower base 2 of the inkjet printer, the powder loaded into the laser selective melting equipment is pretreated CuCrZr alloy powder. When the laser selective melting equipment prints through the upper base 1 of the inkjet printer, the powder loaded into the laser selective melting equipment is pretreated stainless steel alloy powder.

[0062] The specific method of layer-by-layer printing is as follows: after each laser scan is completed, the base plate descends one layer until printing is completed. The laser scanning strategy has an angle of 45° between the scanning lines of the N+1th layer and the Nth layer. After processing, the surface powder needs to be recovered using a powder suction tube, the printed structure is removed, the printed structure is cut and separated from the substrate using wire cutting, and the support is removed.

[0063] S5. Surface treatment:

[0064] The outer surfaces and internal channels of the aforementioned lower chassis 2 and upper chassis 1 parts are surface treated;

[0065] Surface treatment includes one or more of the following: liquid sandblasting, abrasive flow machining, electropolishing, and chemical cleaning.

[0066] S6. Hot isostatic pressing treatment:

[0067] Assemble the lower chassis 2 and the upper chassis 1, and assemble tooling molds on the outer sides of the lower chassis 2 and the upper chassis 1. Attach the upper cover to the outer side of the upper chassis 1, and the lower cover to the outer side of the lower chassis 2. Then, weld and seal the connection between the upper and lower covers. Install a vacuum tube below the lower cover and evacuate to a vacuum level of 1*10 through the vacuum tube. -2 Pa, and argon gas is introduced to maintain the pressure inside the casing at 3Pa. Then, the injector assembly is subjected to hot isostatic diffusion welding using a hot isostatic press. After the hot isostatic diffusion welding is completed, the injector assembly with casing is obtained.

[0068] The specific operation of hot isostatic pressing is as follows: during hot isostatic diffusion welding, the diffusion welding temperature is 920℃, the hot isostatic diffusion welding pressure is 10MPa, and the hot isostatic diffusion welding time is 2h.

[0069] S7. Post-processing:

[0070] The aforementioned encased injector assembly is machined to remove the encasing, and then the surface of the injector assembly is polished. After polishing, a finished injector with a surface roughness Ra of 1.6 μm is obtained.

[0071] Example 2:

[0072] A method for molding an injector assembly includes the following steps:

[0073] S1. Alloy powder preparation:

[0074] The CuCrZr alloy atomized powder and the stainless steel alloy atomized powder were dried in a vacuum drying oven. After drying, they were cooled in the oven. The CuCrZr alloy atomized powder and the stainless steel alloy atomized powder were then subjected to ultrasonic vibration treatment. After ultrasonic vibration treatment, they were sieved through a 270-mesh sieve. The sieve-undersized material was collected to obtain pretreated CuCrZr alloy powder and pretreated stainless steel alloy powder.

[0075] The drying time for CuCrZr alloy atomized powder and stainless steel alloy atomized powder was 5 hours, and the vacuum degree in the vacuum drying oven was 5*10. -4 Pa, the temperature inside the vacuum drying oven is 110℃;

[0076] The ultrasonic vibration treatment time was 8 minutes, the ultrasonic vibration frequency was 38 kHz, and the ultrasonic vibration deviation angle was 9°.

[0077] CuCrZr alloy atomized powder comprises the following components by mass ratio: Cr: 1%, Zr: 0.2%, Fe: 0.05%, Si: 0.05%, with the balance being Cu; stainless steel alloy atomized powder comprises the following components by mass ratio: Ni: 13%, Cr: 17%, Mo: 2.5%, Si: 0.5%, Mn: 1.0%, P: 0.032%, S: 0.01%, C: 0.025%, with the balance being Fe.

[0078] S2. Injector component model design:

[0079] The lower chassis 2 and upper chassis 1 of the injector and the support structure are designed using modeling software. Then, the designed three-dimensional models of the lower chassis 2, upper chassis 1 and support structure are combined to form a three-dimensional solid model with scanning path information for each layer.

[0080] S3. Set printing parameters:

[0081] Import the three-dimensional solid model containing the scanning path information of each layer into the laser selective melting equipment, and set the printing parameters. The three-dimensional models of the upper chassis 1 and the lower chassis 2 are placed vertically with the larger end down and the smaller end up. At the same time, use the splitting software to divide the model into layers to form the laser processing scanning path of each layer.

[0082] The printing parameters for printing the lower chassis 2 are set as follows: the thickness of a single layer of pre-treated CuCrZr alloy powder is 0.04mm, the scanning spacing is 0.08mm, the power is 430W, and the scanning speed is 1000mm / s;

[0083] When printing the upper chassis 1, the printing parameters are set as follows: the thickness of a single layer of pre-treated stainless steel alloy powder is 0.11mm, the scanning interval is 0.13mm, the XY shrinkage ratio is 1.118, the power is 350W, and the scanning speed is 700mm / s.

[0084] S4, Laser Printing:

[0085] The pretreated CuCrZr alloy powder or pretreated stainless steel alloy powder is loaded into the laser selective melting equipment. After the base plate is placed, the scraper is installed. Then, the laser selective melting equipment is evacuated to a vacuum degree of about 4 Pa. Argon gas is then introduced as a protective gas. The powder is evenly spread to the laser processing area by the scraper, and the printing is performed layer by layer according to the printing parameters set in step S3 to obtain the lower base plate 2 and the upper base plate 1 parts.

[0086] When the laser selective melting equipment prints through the lower base 2 of the inkjet printer, the powder loaded into the laser selective melting equipment is pretreated CuCrZr alloy powder. When the laser selective melting equipment prints through the upper base 1 of the inkjet printer, the powder loaded into the laser selective melting equipment is pretreated stainless steel alloy powder.

[0087] The specific method of layer-by-layer printing is as follows: after each laser scan is completed, the base plate descends one layer until printing is completed. The laser scanning strategy has an angle of 70° between the scanning lines of the N+1th layer and the Nth layer. After processing, the surface powder needs to be recovered using a powder suction tube, the printed structure is removed, the printed structure is cut and separated from the substrate using wire cutting, and the support is removed.

[0088] S5. Surface treatment:

[0089] The outer surfaces and internal channels of the aforementioned lower chassis 2 and upper chassis 1 parts are surface treated;

[0090] Surface treatment includes one or more of the following: liquid sandblasting, abrasive flow machining, electropolishing, and chemical cleaning.

[0091] S6. Hot isostatic pressing treatment:

[0092] Assemble the lower chassis 2 and the upper chassis 1, and assemble the tooling molds on the outer sides of the lower chassis 2 and the upper chassis 1. Attach the upper cover to the outer side of the upper chassis 1, and the lower cover to the outer side of the lower chassis 2. Then, weld and seal the connection between the upper and lower covers. Install a vacuum tube below the lower cover and evacuate the vacuum to 5*10 through the vacuum tube. -3 Pa, and argon gas is introduced to maintain the pressure inside the casing at 4Pa. Then, the injector assembly is subjected to hot isostatic diffusion welding using a hot isostatic press. After the hot isostatic diffusion welding is completed, the injector assembly with casing is obtained.

[0093] The specific operation of hot isostatic pressing is as follows: during hot isostatic diffusion welding, the diffusion welding temperature is 980℃, the hot isostatic diffusion welding pressure is 30MPa, and the hot isostatic diffusion welding time is 5h.

[0094] S7. Post-processing:

[0095] The aforementioned encased injector assembly is machined to remove the encasing, and then the surface of the injector assembly is polished. After polishing, a finished injector with a surface roughness Ra of 1.3 μm is obtained.

[0096] Example 3:

[0097] A method for molding an injector assembly includes the following steps:

[0098] S1. Alloy powder preparation:

[0099] The CuCrZr alloy atomized powder and the stainless steel alloy atomized powder were dried in a vacuum drying oven. After drying, they were cooled in the oven. The CuCrZr alloy atomized powder and the stainless steel alloy atomized powder were then subjected to ultrasonic vibration treatment. After ultrasonic vibration treatment, they were sieved through a 270-mesh sieve. The sieve-undersized material was collected to obtain pretreated CuCrZr alloy powder and pretreated stainless steel alloy powder.

[0100] The drying time for CuCrZr alloy atomized powder and stainless steel alloy atomized powder was 10 hours, and the vacuum degree in the vacuum drying oven was 1*10. -4 Pa, the temperature inside the vacuum drying oven is 120℃;

[0101] The ultrasonic vibration treatment time was 10 min, the ultrasonic vibration frequency was 40 kHz, and the ultrasonic vibration deviation angle was 10°.

[0102] CuCrZr alloy atomized powder comprises the following components by mass ratio: Cr: 1.2%, Zr: 0.3%, Fe: 0.03%, Si: 0.03%, with the balance being Cu; stainless steel alloy atomized powder comprises the following components by mass ratio: Ni: 14%, Cr: 18%, Mo: 3%, Si: 0.3%, Mn: 1.0%, P: 0.03%, S: 0.01%, C: 0.01%, with the balance being Fe.

[0103] S2. Injector component model design:

[0104] The lower chassis 2 and upper chassis 1 of the injector and the support structure are designed using modeling software. Then, the designed three-dimensional models of the lower chassis 2, upper chassis 1 and support structure are combined to form a three-dimensional solid model with scanning path information for each layer.

[0105] S3. Set printing parameters:

[0106] Import the three-dimensional solid model containing the scanning path information of each layer into the laser selective melting equipment, and set the printing parameters. The three-dimensional models of the upper chassis 1 and the lower chassis 2 are placed vertically with the larger end down and the smaller end up. At the same time, use the splitting software to divide the model into layers to form the laser processing scanning path of each layer.

[0107] The printing parameters for printing the lower chassis 2 are set as follows: the thickness of a single layer of pre-treated CuCrZr alloy powder is 0.06mm, the scanning spacing is 0.1mm, the power is 460W, and the scanning speed is 1600mm / s;

[0108] When printing the upper chassis 1, the printing parameters are set as follows: the thickness of a single layer of pre-treated stainless steel alloy powder is 0.12mm, the scanning interval is 0.15mm, the XY shrinkage ratio is 1.12, the power is 400W, and the scanning speed is 1000mm / s.

[0109] S4, Laser Printing:

[0110] The pretreated CuCrZr alloy powder or pretreated stainless steel alloy powder is loaded into the laser selective melting equipment. After the base plate is placed, the scraper is installed. Then, the laser selective melting equipment is evacuated to a vacuum degree of about 5 Pa. Argon gas is then introduced as a protective gas. The powder is evenly spread to the laser processing area by the scraper, and the printing is performed layer by layer according to the printing parameters set in step S3 to obtain the lower base plate 2 and the upper base plate 1 parts.

[0111] When the laser selective melting equipment prints through the lower base 2 of the inkjet printer, the powder loaded into the laser selective melting equipment is pretreated CuCrZr alloy powder. When the laser selective melting equipment prints through the upper base 1 of the inkjet printer, the powder loaded into the laser selective melting equipment is pretreated stainless steel alloy powder.

[0112] The specific method of layer-by-layer printing is as follows: after each laser scan is completed, the base plate descends one layer until printing is completed. The laser scanning strategy has an angle of 90° between the scanning lines of the N+1th layer and the Nth layer. After processing, the surface powder needs to be recovered using a powder suction tube, the printed structure is removed, the printed structure is cut and separated from the substrate using wire cutting, and the support is removed.

[0113] S5. Surface treatment:

[0114] The outer surfaces and internal channels of the aforementioned lower chassis 2 and upper chassis 1 parts are surface treated;

[0115] Surface treatment includes one or more of the following: liquid sandblasting, abrasive flow machining, electropolishing, and chemical cleaning.

[0116] S6. Hot isostatic pressing treatment:

[0117] like Figure 4 As shown, the lower chassis 2 and the upper chassis 1 are combined, and tooling molds are assembled on the outer sides of the lower chassis 2 and the upper chassis 1. The upper cover is fastened to the outer side of the upper chassis 1, and the lower cover is fastened to the outer side of the lower chassis 2. Then, the connection between the upper cover and the lower cover is welded and sealed. A vacuum tube is installed below the lower cover, and a vacuum is drawn to 1*10 through the vacuum tube. -3 Pa, and argon gas is introduced to maintain the pressure inside the casing at 5Pa. Then, the injector assembly is subjected to hot isostatic diffusion welding using a hot isostatic press. After the hot isostatic diffusion welding is completed, the injector assembly with casing is obtained.

[0118] The specific operation of hot isostatic pressing is as follows: during hot isostatic diffusion welding, the temperature of diffusion welding is 1000℃, the pressure of hot isostatic diffusion welding is 50MPa, and the duration of hot isostatic diffusion welding is 8h.

[0119] S7. Post-processing:

[0120] The aforementioned encased injector assembly is machined to remove the encasing, and then the surface of the injector assembly is polished. After polishing, a finished injector with a surface roughness Ra of 1.0 μm is obtained.

[0121] Comparative Example 3 - Example 3 shows that the finished injector prepared in Example 3 has the highest strength and the longest service life, therefore Example 3 is the best example.

[0122] Example 4:

[0123] Based on Example 3, this example provides a specific structure for the finished product injector, such as... Figure 1 , Figure 2 , Figure 3 As shown, the finished injector includes an upper chassis 1 and a lower chassis 2. The outer wall of the lower chassis 2 is fixedly connected to the inner wall of the upper chassis 1. The upper chassis 1 includes an upper shell 11, and a fuel chamber 12 is provided between the upper shell 11 and the lower chassis 2. A connecting pipe 13 is fixedly connected to the top of the upper shell 11. The lower chassis 2 includes an injection panel 21, and an oxidizer chamber 22 is provided inside the injection panel 21. Multiple injection units 23 are vertically fixedly connected inside the oxidizer chamber 22. Each injection unit 23 includes an inner cavity 231 and an outer cavity 232. The inner cavity 231... The upper end is connected to the fuel chamber 12, and the lower end of the inner cavity 231 is connected to the lower part of the injection panel 21. The injection panel 21 below the outer wall of the inner cavity 231 has multiple injection holes 233 circumferentially arranged. The outer wall of the outer cavity 232 has multiple circular channels 24 circumferentially distributed, which are connected to the oxidant chamber 22. The lower end of the outer cavity 232 is connected to the lower part of the injection panel 21 through the injection holes 233. The outer side of the injection panel 21 has multiple vertical channels 25 circumferentially distributed, which are connected to the interior of the oxidant chamber 22.

[0124] The finished injector provided in this embodiment sprays fuel through the inner cavity 231 and oxidant through the nozzle 233. The fuel and oxidant are uniformly mixed below the injection panel 21, which is beneficial to improving combustion efficiency. The flow rate and direction of liquid or gas can be controlled by adjusting the number, size and layout of the nozzles 233. The structure of the nozzles 233 can increase the uniformity and stability of the injection.

Claims

1. A method for molding an injection nozzle assembly, characterized in that, Includes the following steps: S1. Preparation of alloy powder: The CuCrZr alloy atomized powder and the stainless steel alloy atomized powder were dried in a vacuum drying oven. After drying, they were cooled in the oven. The CuCrZr alloy atomized powder and the stainless steel alloy atomized powder were then subjected to ultrasonic vibration treatment. After ultrasonic vibration treatment, they were sieved through a 270-mesh sieve. The sieve-undersized material was collected to obtain pretreated CuCrZr alloy powder and pretreated stainless steel alloy powder. S2. Injector component model design: The lower chassis (2), upper chassis (1), and support structure of the injector are designed using modeling software. Then, the designed three-dimensional models of the lower chassis (2), upper chassis (1), and support structure are combined to form a three-dimensional solid model with scanning path information for each layer. S3. Set printing parameters: The above three-dimensional solid model with scanning path information for each layer is imported into the laser selective melting equipment. At the same time, the printing parameters are set. The three-dimensional models of the upper chassis (1) and the lower chassis (2) are placed vertically with the large end down and the small end up. At the same time, the model is divided into layers using the splitting software to form the laser processing scanning path for each layer. S4, Laser Printing: The pretreated CuCrZr alloy powder or pretreated stainless steel alloy powder is filled into the laser selective melting equipment. After the base plate is placed, the scraper is installed. Then the laser selective melting equipment is evacuated to a vacuum of 3-5 Pa. Argon gas is then introduced as a protective gas. The powder is evenly spread to the laser processing area by the scraper. The printing parameters set in step S3 are used to print layer by layer. When the lower base plate (2) of the injector is printed by the laser selective melting equipment, the powder filled in the laser selective melting equipment is pretreated CuCrZr alloy powder. When the upper base plate (1) of the injector is printed by the laser selective melting equipment, the powder filled in the laser selective melting equipment is pretreated stainless steel alloy powder. The lower base plate (2) and upper base plate (1) parts are obtained. S5. Surface treatment: Surface treatment is performed on the outer surfaces and internal channels of the lower chassis (2) and upper chassis (1) parts mentioned above; S6. Hot isostatic pressing treatment: Combine the lower chassis (2) and the upper chassis (1), and assemble tooling molds on the outside of the lower chassis (2) and the upper chassis (1). Attach the upper cover to the outside of the upper chassis (1) and the lower cover to the outside of the lower chassis (2). Then weld and seal the connection between the upper cover and the lower cover. Install a vacuum tube below the lower cover and evacuate to 1*10 through the vacuum tube. -2 -1*10 -3 Pa, and argon gas is introduced to maintain the pressure inside the casing at 3-5 Pa. Then, the injector assembly is subjected to hot isostatic diffusion welding using a hot isostatic press. After the hot isostatic diffusion welding is completed, the injector assembly with casing is obtained. S7. Post-processing: The aforementioned encased injector assembly is machined to remove the encasing, and then the surface of the injector assembly is polished. After polishing, a finished injector with a surface roughness Ra≤1.6μm is obtained.

2. The molding method of an injection nozzle assembly as described in claim 1, characterized in that, In step S3, the printing parameters for printing the lower chassis (2) are set as follows: the thickness of a single layer of pre-treated CuCrZr alloy powder is 0.03-0.06 mm, the scanning spacing is 0.05-0.1 mm, the power is 400-460 W, and the scanning speed is 400-1600 mm / s.

3. The molding method of an injection nozzle assembly as described in claim 1, characterized in that, In step S3, the printing parameters for printing the upper chassis (1) are set as follows: the thickness of a single layer of pre-treated stainless steel alloy powder is 0.05-0.12mm, the scanning distance is 0.08-0.15mm, the XY shrinkage ratio is 1.115-1.12, the power is 300-400W, and the scanning speed is 400-1000mm / s.

4. The molding method of an injection nozzle assembly as described in claim 1, characterized in that, The surface treatment in step S5 includes one or more of the following: liquid sandblasting, abrasive flow machining, electropolishing, and chemical cleaning.

5. The molding method of an injection nozzle assembly as described in claim 1, characterized in that, In step S6, the specific operation of the hot isostatic pressing treatment is as follows: during the hot isostatic diffusion welding, the diffusion welding temperature is 920-1000℃, the hot isostatic diffusion welding pressure is 10-50MPa, and the hot isostatic diffusion welding time is 2-8h.

6. The molding method of an injection nozzle assembly as described in claim 1, characterized in that, In step S1, the drying time for CuCrZr alloy atomized powder and stainless steel alloy atomized powder is 4-10 hours, and the vacuum degree in the vacuum drying oven is 1*10. -3 -1*10 -4 Pa, the temperature inside the vacuum drying oven is 100-120℃.

7. The molding method of an injection nozzle assembly as described in claim 1, characterized in that, In step S1, the ultrasonic vibration treatment lasts for 5-10 minutes, the ultrasonic vibration frequency is 35-40 kHz, and the ultrasonic vibration deviation angle is 8-10°.

8. The molding method of an injection nozzle assembly as described in claim 1, characterized in that, In step S1, the ultrasonic vibration treatment lasts for 5-10 minutes and the ultrasonic vibration frequency is 35-40 kHz.

9. A method for molding an injection nozzle assembly as described in claim 1, characterized in that, The finished injector in step S7 includes an upper chassis (1) and a lower chassis (2). The outer wall of the lower chassis (2) is fixedly connected to the inner wall of the upper chassis (1). The upper chassis (1) includes an upper shell (11). A fuel chamber (12) is provided between the upper shell (11) and the lower chassis (2). A connecting pipe (13) is fixedly connected to the top of the upper shell (11). The lower chassis (2) includes an injection panel (21). An oxidant chamber (22) is provided inside the injection panel (21). Multiple injection units (23) are vertically fixedly connected inside the oxidant chamber (22). Each injection unit (23) includes an inner cavity (231) and an outer cavity (232). The inner cavity (231) The upper end of the inner cavity (231) is connected to the fuel chamber (12), the lower end of the inner cavity (231) is connected to the lower part of the injection panel (21), the injection panel (21) below the outer wall of the inner cavity (231) is provided with a plurality of injection holes (233) in the circumferential direction, the outer wall of the outer cavity (232) is provided with a plurality of circular channels (24) in the circumferential direction, the circular channels (24) are connected to the oxidant chamber (22), the lower end of the outer cavity (232) is connected to the lower part of the injection panel (21) through the injection holes (233), the outer side of the injection panel (21) is provided with a plurality of vertical channels (25) in the circumferential direction, and the plurality of vertical channels (25) are connected to the interior of the oxidant chamber (22).

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