CN-121988697-A - 3D printing method for sand mold of pump housing part of space liquid rocket engine

CN121988697ACN 121988697 ACN121988697 ACN 121988697ACN-121988697-A

Abstract

According to the 3D printing method of the sand mould of the complex pump housing part of the space liquid rocket engine, according to the structural characteristics of the product, by combining the 3D printing process characteristics of the sand mould, a proper process scheme is designed, a reasonable positioning mode is determined, and the digital simulation software is used to realize the rapid verification of the casting scheme, so that the difficult problem of the application of the sand mould 3D printing technology to the complex pump housing part is solved, and the purposes of rapid production and rapid verification of the product are achieved. The invention is mainly used for manufacturing the sand mould 3D printing process of the high-working-condition, complex-stress and pressure-bearing type aluminum alloy pump housing part with the variable-section vortex, can greatly shorten the development period, improve the dimensional accuracy and the dimensional stability, solve the problem that the traditional casting needs to design and verify the mould produced first, reduce the assembly quantity, expand the casting application range, provide technical support for the advanced design concept, and lay a solid foundation for the high-quality and high-efficiency production of the product.

Inventors

WANG YU
FAN ZHANCHAO
JI YANQING
REN XINMIAO
ZHANG PENG
WU XIAOMING
GAO HUAISHENG

Assignees

西安航天发动机有限公司

Dates

Publication Date: 20260508
Application Date: 20241011

Claims (14)

1. A3D printing method for a part sand mould of a pump housing part of a space liquid rocket engine is characterized by comprising the following steps: (1) Designing a sand mold 3D printing scheme, setting 3 parting surfaces, 4 sand molds and 1 sand core, setting a positioning core head (101) between the sand cores and the sand molds for positioning and fixing, wherein the parting surfaces are sequentially a first parting surface (7), a second parting surface (8) and a third parting surface (9) from bottom to top, the first parting surface (7) is arranged at the positioning core head (101), the second parting surface (8) is arranged at the center of a vortex channel (102), and the third parting surface (9) is arranged at the maximum flange (103); (2) Setting printing parameters and Z-axis compensation, and performing sand core printing production; (3) Placing the sand mould core obtained in the step (2) for more than 4 hours, brushing a coating on the surface of the sand mould core until no exposed molding sand matrix exists, and drying; (4) Sequentially assembling the sand mould cores obtained in the step (3) according to a design scheme; (5) Preparing materials according to the required alloy components, smelting and refining to obtain an alloy melt, and pouring the alloy melt into the sand mould sand core obtained in the step (4) to obtain a casting; (6) Placing the casting obtained in the step (5) to be cooled, and then performing shakeout cleaning; (7) Sawing a riser of the casting obtained in the step (6), finishing, and then performing sand blasting treatment; (8) And (3) carrying out heat treatment on the casting obtained in the step (7) to obtain the target casting.
2. The 3D printing method for the sand mould of the pump housing part of the space liquid rocket engine is characterized in that a pouring system is a bottom pouring system (2), a pouring channel is a snake-shaped straight pouring channel (3), a blind riser (4) is arranged on a horizontal pouring channel, a feeding riser (5) is arranged on the top of the horizontal pouring channel, and a side riser (6) is arranged on an outlet flange.
3. The 3D printing method for the pump housing part sand mold of the space liquid rocket engine according to claim 1, wherein the positioning core head (101) is semi-annular, and the fit clearance is 0.2-0.3 mm.
4. The 3D printing method for the sand mould of the pump housing part of the space liquid rocket engine is characterized in that a first sand mould, a second sand mould, a third sand mould and a fourth sand mould are sequentially arranged from bottom to top, adjacent sand moulds are connected through matched convex positioning devices and concave positioning devices, four through holes (12) are formed in the same positions of the first sand mould to the fourth sand mould, and bolts penetrate through the through holes (12) to fix the sand mould.
5. The 3D printing method for the pump housing part sand mold of the space liquid rocket engine according to claim 4, wherein an air vent groove (16) is formed in the outer surface of the bottom of the second sand mold, an air vent hole (17) is formed in the bottom of the air vent groove, a T-shaped structure (18) is formed in the outer surface of the top of the air vent groove and used for fixing a main sand core, the upper half part of the T-shaped structure (18) is cuboid, and the lower half part of the T-shaped structure is round table.
6. The 3D printing method for the pump housing part sand mold of the space liquid rocket engine according to claim 1, wherein mortise and tenon structures (26) are arranged on a sand core, trapezoid positioning devices (27) are arranged at the end heads of the sand core, and the trapezoid positioning devices (27) are uniformly distributed along the center of the sand core at intervals of 120 degrees.
7. The 3D printing method for the sand mould of the pump housing part of the space liquid rocket engine is characterized in that the sand mould and the outer surface of a casting follow-up, the sand eating amount is 40-50 mm, and the sand core is of a hollow structure.
8. The 3D printing method for the part sand mould of the pump housing of the space liquid rocket engine is characterized in that a chill is arranged on a sand mould, the installation mode of the chill is that a locating hole (21) is formed in the corresponding position of the sand mould by the downward installation of the chill, the downward installation of the chill is adhered to the corresponding position by using resin glue, the setting gap is 0.2-0.3 mm, a convex locating block is arranged on the installation surface of the chill, and a locating block installation hole is formed in the corresponding sand mould installation position of the chill for fixing the chill.
9. The 3D printing method for the pump housing part sand mold of the space liquid rocket engine according to claim 1 is characterized in that in the step (2), the thickness of a printing layer is 0.2-0.3 mm, the printing speed is set to 300-400 mm/s, the Z axis is perpendicular to the first parting surface (7), and the Z axis compensation is set to 0.2-0.3 mm.
10. The 3D printing method for the pump housing part sand mold of the space liquid rocket engine, which is disclosed in claim 1, is characterized in that the paint in the step (3) is water-based, the paint viscosity is 40-80 Bes, and the brushing mode is manual coating.
11. The 3D printing method for the pump housing part sand mould of the space liquid rocket engine, which is disclosed in claim 4, is characterized in that the third sand mould vortex path part is arranged to be a hollow structure (22), an SR60mm hemispherical reinforcement structure (23) is arranged locally, and a reinforcing rib plate (25) is arranged at the top of the fourth sand mould.
12. The 3D printing method for the pump housing part sand mold of the space liquid rocket engine is characterized by comprising the following steps of (5) carrying out alloy liquid refining by using a refining degassing machine after smelting and clearing, adding a refining agent accounting for 0.3% -0.4% of the alloy weight when the alloy liquid reaches 710-720 ℃, carrying out primary refining, wherein the parameters are that the argon gas source pressure is 0.5MP a after depressurization, the degassing and refining time is 10-15 minutes, the rotating speed of a graphite rotor is 200-400 rpm during pretreatment, the rotating speed of the graphite rotor is 400-600 rpm during degassing and refining, the alloy standing time is 5-10 minutes, heating the alloy liquid to 710-730 ℃ after standing, pressing a baked magnesium block into the alloy liquid to the position of 100-150 mm at the bottom of the crucible by using a bell jar, slowly rotating 30-35 s clockwise, taking out the bell jar after the magnesium block is completely melted, lifting the alloy liquid temperature to 740-750 ℃, drying an aluminum strontium alloy rod coated with aluminum foil, pressing the bell jar into the position to the position of the bottom of the alloy liquid for carrying out secondary stirring, carrying out uniform motion for 740-20 minutes after the magnesium block is completely melted, carrying out secondary refining, and carrying out refining for 3-20 minutes after the alloy liquid is uniformly stirring.
13. The 3D printing method for the pump housing part sand mold of the space liquid rocket engine, which is disclosed in claim 1, is characterized in that the heat treatment process parameters in the step (8) are that the solution treatment temperature is 530-540 ℃, the heat preservation time is 3-6 hours, the aging treatment temperature is 170-180 ℃, the heat preservation time is 5-10 hours, and the cooling mode is air cooling.
14. The 3D printing method for the sand mould of the pump housing part of the space liquid rocket engine according to claim 1, wherein the casting obtained in the step (8) is subjected to X-ray internal inspection, size inspection and surface quality inspection, a finished casting is obtained after the inspection is passed, and the casting is scrapped after the inspection is not passed.

Description

3D printing method for sand mold of pump housing part of space liquid rocket engine Technical Field The invention belongs to the technical field of sand casting, and particularly relates to a 3D printing method for a pump housing part sand mold of a space liquid rocket engine. Background The complex pump housing of the pressure-bearing variable-section vortex is a common structure of a fuel gas or liquid flow outlet of a pump type liquid rocket engine pre-pressure pump, an oxidant pump, a fuel pump and other components, and design parameters of the fuel gas or liquid flow are controlled through the size and the shape of the variable-section vortex. In order to meet the weight reduction requirement, the thin wall of the vortex channel is designed to be uniformly attached, meanwhile, reinforcing ribs with different shapes are uniformly added on the outer wall, and the materials are also selected to be light aluminum alloy and magnesium alloy. As a pressure-bearing structural member, the pressure-bearing structural member needs to bear high-pressure impact of fuel gas or liquid flow, has high requirements on the quality of castings, is generally I-class castings, has no casting defects such as cracks, cold partitions, sand holes, shrinkage cavities, air holes and the like allowed on the surface, is based on reliability consideration, and does not allow repair by repair welding, so that the high requirements are put forward on casting. The sand mold 3D printing technology is combined with the casting technology, the constraint of the traditional preparation technology is broken, the three-dimensional computer design, the selective ink-jet technology, the new technology and the new material are integrated, the sand mold (core) is directly prepared in a mode of stacking materials layer by layer under the condition of no mold, and along with the introduction of the technology, the quality stability of the product is improved, the production cost is reduced, the controllability of the quality of the sand mold is greatly improved, the production efficiency of the technology and the combination of the advantages are greatly shortened, and the technical conditions are created for the rapid updating iteration of the rocket engine casting product. Shi Guquan in the application of 3D printing sand mould in casting shows that the sand mould additive manufacturing technology has been widely applied to parts of a fork truck torque converter and parts of a cylinder body of a4 cylinder of an automobile engine, but has relatively few applications in the field of complex parts of an aerospace engine. He Jiejun in the application of casting sand mould 3D printing technology and the hope shows that the combination of the 3D printing technology and the traditional sand casting technology is widely applied to the development and manufacture of key parts in the aviation field, but is not widely applied to the manufacture of complex parts in the aerospace engine field. Disclosure of Invention The invention aims to provide a 3D printing method for a pump shell part sand mould of a space liquid rocket engine, which is characterized in that a sand mould structure, a hollow main sand core structure and a special positioning design structure are arranged by designing a sand mould 3D printing scheme, so that reasonable solidification sequence is ensured, meanwhile, the cooling time of a casting is shortened, and the quality and the dimensional accuracy of the casting are improved so as to meet the requirements of special working environments. The above object of the present invention is mainly achieved by the following technical solutions: A3D printing method for a pump housing part sand mold of a space liquid rocket engine comprises the following steps: (1) Designing a sand mold 3D printing scheme, setting 3 parting surfaces, setting 4 sand molds and 1 sand core, setting a positioning core head between the sand cores and the sand molds for positioning and fixing, wherein the parting surfaces sequentially comprise a first parting surface, a second parting surface and a third parting surface from bottom to top, the first parting surface is arranged at the positioning core head, the second parting surface is arranged at the center of a vortex path, and the third parting surface is arranged at the maximum flange; (2) Setting printing parameters and Z-axis compensation, and performing sand core printing production; (3) Placing the sand mould core obtained in the step (2) for more than 4 hours, brushing a coating on the surface of the sand mould core until no exposed molding sand matrix exists, and drying; (4) Sequentially assembling the sand mould cores obtained in the step (3) according to a design scheme; (5) Preparing materials according to the required alloy components, smelting and refining to obtain an alloy melt, and pouring the alloy melt into the sand mould sand core obtained in the step (4) to obtain a casting; (6) Placing the castin