Chemical polishing surface preparation method for thrust device holders with narrow channel lumen structure
The chemical polishing method for thrust device holders addresses surface roughness and powder particle issues, providing smooth liquid flow and reliable quality by using a hydrofluoric and nitric acid solution, reducing roughness and preventing corrosion.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- XIAN SPACE ENGINE CO LTD
- Filing Date
- 2024-11-15
- Publication Date
- 2026-06-11
AI Technical Summary
Existing methods struggle to effectively polish and finish the narrow channels of thrust device holders with high surface roughness and adhering metal powder particles, leading to performance limitations and potential impurity generation under high-pressure and high-speed liquid flow conditions.
A chemical polishing and surface finishing method using a solution of hydrofluoric acid, nitric acid, and additives is applied to the thrust device holder, ensuring uniform dissolution of powder particles and reducing surface roughness without deformation or defects, while maintaining precise liquid flow.
The method achieves smooth liquid flow, reduces surface roughness, eliminates corrosion, and prevents hydrogen embrittlement, ensuring reliable product quality and consistent liquid flow.
Smart Images
Figure 2026518910000001_ABST
Abstract
Description
Technical Field
[0001] Cross - reference to related applications This application claims the priority of the patent application No. 202410531011.6 (Title of the Invention: Chemical Polishing and Surface Finishing Method of the Thrust Device Holder with a Narrow Channel Inner Cavity Structure) filed with the China National Intellectual Property Administration on April 29, 2024, and the entire content thereof is incorporated herein by reference.
[0002] The present invention relates to a chemical polishing and surface finishing method for a thrust device holder with a narrow channel inner cavity structure and belongs to the field of chemical polishing and surface finishing applications.
Background Art
[0003] A certain model of engine thrust device holder is installed between the valve and the thrust chamber, and is used to ensure the opening of the valve and the transportation of fuel and oxidizer. It is an important functional part that generates the thrust required by the engine (Figure 1). The thrust device holder has many inner cavities, narrow channels, and the smallest part is only 0.2 mm. It is formed by additive manufacturing. The surface roughness of the additive manufacturing product is as high as 10 - 15 μm, and a large amount of metal powder particles adhere to it. Therefore, the use performance of the product is significantly limited, and there is a risk that the powder particles adhering to the inner cavity will fall off and generate impurities under the rinsing environment of high temperature, high pressure, and high - speed liquid flow. In addition, the aperture diameter of the liquid flow holes of the thrust device holder is closely related to the liquid flow data, and the accuracy of the final size of the aperture diameter directly affects the qualification rate of the liquid flow.
Summary of the Invention
[0004] The technical problem to be solved by the present invention is to overcome the deficiencies of the prior art, chemically polish and surface finish the channels inside the thrust device holder, remove the powder particles on the surface, reduce the roughness, and ensure the qualification of the liquid flow of the thrust device holder.
[0005] The object of the present invention is achieved by the following technical means.
[0006] The chemical polishing and surface finishing method for a thrust device holder with a narrow channel inner cavity structure includes the following steps. (1) The connector is attached to the thrust device holder and tested with water to detect whether the flow rate at the outlet of the internal passage is normal or not. Hoses are connected to the inlets A, B, and C (Figure 1) of the three passages: the oxidizer passage, the fuel passage, and the gas passage. The three hoses are then connected to the connection port a of the four-way connector (Figure 2), the inlets of the pipelines are secured with clips, and the other end b of the four-way connector is connected to the diaphragm pump. The diaphragm pump is opened, the pressure is adjusted, and tap water is introduced into the lumen of the product to detect whether the flow rate at the outlet is uniform. (2) After testing with water, the chemical polishing and surface finishing solution is introduced into the lumen of the thrust device holder. A chemical polishing and surface finishing solution is introduced into the lumen of the product at room temperature. The chemical polishing and surface finishing solution contains 60-80 g / L of hydrofluoric acid (HF, 1.27), 70-90 g / L of nitric acid (HNO3, 1.5), and 0.2 g / L of an additive. The pressure of the chemical polishing and surface finishing pump is 0.2-0.5 kg / cm². 3 The time required for chemical polishing and surface preparation is 2 minutes. (3) Pickling of the entire component To ensure uniform color across the entire component, the entire component is immersed in an acid solution for 5 to 10 seconds at room temperature. The formulation and concentration of the acid solution are 40-60 g / L of hydrofluoric acid (HF, 1.27) and 320-370 g / L of nitric acid (HNO3, 1.5).
[0007] The present invention has the following beneficial effects compared to the prior art. (1) The chemical polishing and surface finishing products of the present invention are additively manufactured molded articles with many narrow internal channels. The internal channels of these products are difficult to polish and surface finish by conventional physical methods such as abrasive flow and mechanical polishing. According to the present invention, uniform dissolution of powder particles in the internal channels of the product is achieved, resulting in no deformation of the processed product and no defects such as processing stress. (2) After chemical polishing and surface finishing, the surface roughness of the lumen is reduced, there are no unwanted substances such as powder particles, and the consistency of the liquid flow results of the product is good. (3) The chemically polished luminal surface is free from corrosion (Figure 3), and the hydrogen content is 0.00075%, which is far lower than the standard value of 0.002%, thus eliminating the risk of hydrogen embrittlement. (4) By adding additives, the escape of acid mist during the chemical processing is reduced, and environmental pollution is avoided. (5) The precise polishing and finishing conditions of the additive manufacturing components provided in the present invention ensure smooth liquid flow holes, achieving the objective of ensuring acceptable liquid flow and reliable product quality. [Brief explanation of the drawing]
[0008] [Figure 1] This is an external view of the thruster. [Figure 2] This is a schematic diagram of a four-way connector. [Figure 3] This is the external appearance of the internal cavity of the thrust device holder. [Figure 4] This is a schematic diagram showing the location of the liquid flow detection port. [Modes for carrying out the invention]
[0009] To further clarify the object, technical means, and advantages of the present invention, embodiments of the present invention will be described below with reference to the drawings.
[0010] Example 1 A chemical polishing surface preparation method for a thrust device holder with a narrow channel lumen structure includes the following steps (1) to (3). Step (1): Attach the connector to the thrust device holder and test with water to determine if the flow rate at the outlet of the lumen is normal. Step (2): Introduce the chemical polishing solution into the lumen of the thruster holder. A chemical polishing and surface finishing solution is introduced into the lumen of the product at room temperature. The chemical polishing and surface finishing solution contains 60 g / L of hydrofluoric acid (HF, 1.27), 90 g / L of nitric acid (HNO3, 1.5), and 0.2 g / L of an additive (belonging to an acid mist inhibitor, for example, sodium lauryl sulfate), with the remainder being water. The pressure of the chemical polishing and surface finishing pump is 0.3 kg / cm². 3 The chemical polishing surface preparation time is 120 seconds. Step (3): Pickling of the entire part To ensure uniform color across the entire component, the entire component is immersed in an acid solution for 5 seconds at room temperature. The composition and concentration of the acid solution are 50 g / L of hydrofluoric acid (HF, 1.27) and 320 g / L of nitric acid (HNO3, 1.5), with the remainder being water. As a result of the liquid flow test of the product after chemical polishing and surface preparation, the oxidizer passage A1 measured 66.525 MPa and the fuel passage B1 measured 40.115 MPa, both meeting the requirements. The locations of A1 and B1 are shown in Figure 4.
[0011] Example 2 A chemical polishing surface preparation method for a thrust device holder with a narrow channel lumen structure includes the following steps (1) to (3). Step (1): Attach the connector to the thrust device holder and test with water to determine if the flow rate at the outlet of the lumen is normal. Step (2): Introduce the chemical polishing solution into the lumen of the thruster holder. A chemical polishing and surface finishing solution is introduced into the lumen of the product at room temperature. The chemical polishing and surface finishing solution contains 75 g / L of hydrofluoric acid (HF, 1.27), 85 g / L of nitric acid (HNO3, 1.5), and 0.2 g / L of an additive, with the remainder being water. The pressure of the chemical polishing and surface finishing pump is 0.5 kg / cm². 3 The chemical polishing surface preparation time is 90 seconds. Step (3) Pickling of the entire component Step (3): Pickling of the entire part To ensure uniform color across the entire component, the entire component is immersed in an acid solution for 10 seconds at room temperature. The composition and concentration of the acid solution are 60 g / L of hydrofluoric acid (HF, 1.27) and 350 g / L of nitric acid (HNO3, 1.5), with the remainder being water. As a result of the liquid flow test of the product after chemical polishing and surface preparation, the oxidizer passage A1 measured 66.594 MPa and the fuel passage B1 measured 39.759 MPa, both of which meet the requirements.
[0012] Example 3 A chemical polishing surface preparation method for a thrust device holder with a narrow channel lumen structure includes the following steps (1) to (3). Step (1): Attach a connector to the thrust device holder and measure whether the flow rate at the liquid outlet of the inner cavity is normal by testing with water. Step (2): Introduce the chemical polishing and surface finishing solution into the inner cavity of the thrust device holder. Introduce the chemical polishing and surface finishing solution into the inner cavity of the product at room temperature. The chemical polishing and surface finishing solution contains 80 g / L of hydrofluoric acid (HF, 1.27), 90 g / L of nitric acid (HNO3, 1.5), and 0.2 g / L of additive, with the balance being water. The pressure of the chemical polishing and surface finishing pump is 0.4 kg / cm 3 and the chemical polishing and surface finishing time is 110 s. Step (3): Pickling of the whole part To ensure the uniformity of the color of the whole part, immerse the whole part in the acid solution at room temperature for 8 s. The formulation and concentration of the acid solution are 40 g / L of hydrofluoric acid (HF, 1.27) and 370 g / L of nitric acid (HNO3, 1.5), with the balance being water. As a result of the product liquid flow test after chemical polishing and surface finishing, the oxidant passage A1 is 58.277 MPa and the fuel passage B1 is 38.587 MPa, meeting the requirements.
[0013] Contents not described in detail in the specification of the present invention are well known to those skilled in the art. The present invention has been disclosed as above in preferred embodiments, but it is not intended to limit the present invention. Those skilled in the art can change and modify the technical means of the present invention according to the above methods and technical contents within the idea and scope of the present invention. Therefore, any simple modification, equivalent change, and modification added to the above embodiments by the substantial technology of the present invention without departing from the technical means of the present invention are all included in the protection scope of the present invention.
Claims
1. A method for chemically polishing and smoothing the surface of a thrust device holder with a narrow channel lumen structure, A step to test the internal passage of the thrust device holder with water to confirm whether the flow rate is normal, A chemical polishing and surface finishing solution is introduced into the internal passage of the thrust device holder by a pump, and the internal passage is chemically polished and surface finished. The chemical polishing and surface finishing solution contains 60-80 g / L of HF and HNO. ３ A step in which the solution contains 70-90 g / L, 0.2 g / L of additives, and the remainder is water. After chemical polishing and surface preparation, the entire thrust device holder is chemically pickled. The chemical pickling solution consists of 40-60 g / L of HF and HNO. ３ The step involves a mixture containing 320-370 g / L, with the remainder being water. A chemical polishing and surface finishing method characterized by including the following.
2. The chemical polishing surface finishing method according to claim 1, characterized in that the thrust device holder is provided with an oxidizer passage inlet A, a fuel passage inlet B, and a gas passage inlet C, three of which are connected by a four-way connector, the remaining port of the four-way connector is connected to a diaphragm pump, and the method is tested with water.
3. The chemical polishing and surface finishing method according to claim 1, characterized in that the temperature of the chemical polishing and surface finishing solution is at room temperature.
4. The chemical polishing time is 90–120 seconds, and the pressure is 0.2–0.5 kg / cm². ３ The chemical polishing surface finishing method according to claim 1, characterized in that it is the same as described above.
5. The chemical polishing and surface finishing method according to claim 1, characterized in that the chemical pickling time is 5-10 seconds.
6. The chemical polishing surface preparation method according to claim 1, characterized in that the additive is sodium lauryl sulfate.
7. A thrust device holder with a narrow channel lumen structure, characterized in that its surface is chemically polished by the chemical polishing surface finishing method described in any one of claims 1 to 6.
8. The narrow channel lumen structure thrust device holder according to claim 7, characterized in that the width of the minimum point of the channel in the lumen is 0.2 mm.
9. The narrow channel lumen structure thrust device holder according to claim 7, characterized in that the narrow channel lumen structure thrust device holder is molded by additive manufacturing and has a surface roughness of 10 to 15 μm.
10. The narrow channel lumen structure thrust device holder according to claim 7, characterized in that the narrow channel lumen structure thrust device holder is free from the risk of hydrogen embrittlement after being chemically polished and smoothed.