Chemical finishing method for thrust device mount having inner cavity structure with narrow flow channels

Abstract

The present invention belongs to the technical field of the chemical finishing of additive manufacturing products. Disclosed is a chemical finishing method for a thrust device mount having an inner cavity structure with narrow flow channels. A chemical finishing solution comprises the following components: HF: 60-80 g / L, HNO3: 70-90 g / L, and an additive: 0.2 g / L, with the balance being water. The parameters of chemical finishing are as follows: the pump pressure is 0.2-0.5 kg / cm3, and the chemical finishing time is 2 min. The chemical finishing method for the inner cavity of an additive manufacturing product provided by the embodiments of the present invention polishes and flattens the inner cavity which is difficult to polish and flatten by means of conventional physical methods such as abrasive flow machining and mechanical polishing, and achieves uniform dissolution of powder particles in the inner cavity of a product, and the processed product is free of deformation, processing stress defects, the risk of hydrogen embrittlement, etc. By adding the additive, the amount of an acid mist that escapes during a chemical finishing process is reduced, and environmental pollution is avoided. By means of the chemical finishing method provided by the embodiments of the present invention, a flow channel in an inner cavity of a processed part has a good surface quality, and the liquid flow meets the requirements.

Description

Chemical finishing method for narrow flow channel inner cavity structure thrust device support

[0001] Cross-reference to Related Applications

[0002] The present application claims priority to the Chinese patent application No. 202410531011.6, filed on April 29, 2024, and entitled “Chemical finishing method for narrow flow channel inner cavity structure thrust device support”, the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to a chemical finishing method for a narrow flow channel inner cavity structure thrust device support, belonging to the field of chemical finishing applications. BACKGROUND

[0004] A certain type of engine thrust device support is installed between the valve and the thrust chamber, used to ensure the opening of the valve and the delivery of fuel agent and oxidizing agent, and is an important functional component for generating the required thrust of the engine, as shown in FIG. 1. The thrust device support has multiple inner cavities and narrow flow channels, with the smallest being only 0.2 mm, and is currently manufactured by additive manufacturing. The surface roughness of the additive manufacturing product is as high as 10-15 μm, and a large number of metal powder particles are adhered, which seriously restricts the performance of the product. At the same time, the inner cavity adhered powder particles have the risk of falling off and generating excess material under the environment of high temperature, high pressure, and high-speed liquid flow. In addition, the aperture of the liquid flow hole of the thrust device support is closely related to the liquid flow data, and the final size precision of the aperture directly affects the liquid flow qualification rate. SUMMARY

[0005] The technical problem to be solved by the present application is to overcome the shortcomings of the prior art, so that the inner flow channel of the thrust device support can be chemically finished, the surface powder particles can be removed, the roughness can be improved, and the liquid flow qualification of the thrust device support can be ensured.

[0006] The object of the present application is achieved by the following technical solutions:

[0007] A chemical finishing method for a narrow flow channel inner cavity structure thrust device support, comprising:

[0008] (1) Install the tooling of the thrust device support and test the water, mainly to check whether the flow of the liquid outlet of the inner cavity is normal.

[0009] Connect the inlets A, B and C (as shown in FIG. 1) of the three channels: the oxidizing agent channel, the fuel channel and the gas channel to the pipe openings, connect the A, B and C ports to the hoses respectively, connect the three hoses to the four-way tooling (as shown in FIG. 2) interface a respectively, fix the pipe inlets with the clamp, and connect the other end b of the four-way tooling to the pneumatic diaphragm pump. Turn on the pneumatic diaphragm pump, adjust the pressure, and pour tap water into the product inner cavity. Observe that the flow of the liquid outlet should be uniform in size.

[0010] (2) After water test, the chemical finishing solution is injected into the inner cavity of the thrust device support.

[0011] The chemical finishing solution is injected into the inner cavity of the product at room temperature, and the chemical finishing solution comprises the following components: hydrofluoric acid (HF, 1.27) 60-80 g / L, nitric acid (HNO3, 1.5) 70-90 g / L, and additives 0.2 g / L. The chemical finishing pump pressure is 0.2-0.5 kg / cm 3 , and the chemical finishing time is 2 min.

[0012] (3) Overall pickling of the part

[0013] In order to ensure the uniformity of the color of the part, the part is soaked in an acid solution at room temperature for 5-10 s, and the formula and concentration of the acid solution are as follows: hydrofluoric acid (HF, 1.27) 40-60 g / L, nitric acid (HNO3, 1.5) 320-370 g / L.

[0014] Compared with the prior art, the present application has the following beneficial effects:

[0015] (1) The product object of the chemical finishing of the present application is an additive manufacturing product with many and narrow inner cavity flow channels. The inner cavity of the product is difficult to be polished and flattened by conventional abrasive flow, mechanical polishing and other physical methods. The present application realizes uniform dissolution of powder particles in the inner cavity of the product, and the processed product has no deformation, no processing stress defects, etc.

[0016] (2) After chemical finishing, the inner cavity surface roughness is reduced, there are no powder particles and other excess substances, and the product liquid flow consistency is good.

[0017] (3) After chemical finishing, the inner cavity surface has no corrosion, as shown in Figure 3; and the hydrogen content increment is 0.00075%, which is much smaller than the standard value of 0.002%, and there is no risk of hydrogen embrittlement.

[0018] (4) By adding additives, the escape of acid mist during chemical processing is reduced, and environmental pollution is avoided.

[0019] (5) The precise finishing conditions provided by the present application ensure that the liquid flow hole wall is smooth, and the purpose of meeting the liquid flow qualification and reliable product quality can be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is an appearance view of a thrust device.

[0021] Figure 2 is a schematic view of a four-way butt joint tool.

[0022] Figure 3 is an appearance morphology of the inner cavity of the thrust device support.

[0023] Figure 4 is a schematic view of the position of the liquid flow detection port. DETAILED DESCRIPTION

[0024] The object, technical solutions and advantages of the present application will be more apparent from the following detailed description of the embodiments of the present application, taken in conjunction with the accompanying drawings.

[0025] Example 1

[0026] A chemical polishing method for a narrow flow passage inner cavity structure thrust device support includes:

[0027] Step (1) installing tooling and testing water for the thrust device support, and the flow of the liquid outlet of the inner cavity passage is normal.

[0028] Step (2) injecting a chemical polishing solution into the inner cavity of the thrust device support.

[0029] The chemical polishing solution is injected into the inner cavity of the product at room temperature, and the chemical polishing solution contains the following components: hydrofluoric acid (HF, 1.27) 60 g / L, nitric acid (HNO3, 1.5) 90 g / L, and an additive (an acid mist inhibitor such as sodium dodecyl sulfate) 0.2 g / L, and the balance is water. The chemical polishing pump pressure is 0.3 kg / cm 3 , and the chemical polishing time is 120 s.

[0030] Step (3) overall pickling of the part

[0031] To ensure that the overall color of the part is uniform, the part is immersed in an acid solution at room temperature for 5 s, and the formula and concentration of the acid solution are hydrofluoric acid (HF, 1.27) 50 g / L, nitric acid (HNO3, 1.5) 320 g / L, and the balance is water.

[0032] The liquid flow test results of the product after chemical polishing are oxidant path A 166.525 MPa and fuel path B 140.115 MPa, which meet the requirements, and the positions of A1 and B1 are shown in FIG. 4.

[0033] Example 2

[0034] A chemical polishing method for a narrow flow passage inner cavity structure thrust device support includes:

[0035] Step (1) installing tooling and testing water for the thrust device support, and the flow of the liquid outlet of the inner cavity passage is normal.

[0036] Step (2) injecting a chemical polishing solution into the inner cavity of the thrust device support.

[0037] The chemical polishing solution is injected into the inner cavity of the product at room temperature, and the chemical polishing solution comprises the following components: hydrofluoric acid (HF, 1.27) 75g / L, nitric acid (HNO3, 1.5) 85g / L and additives 0.2g / L, and the rest is water. The chemical polishing pump pressure is 0.5kg / cm 3 , and the chemical polishing time is 90s.

[0038] Step (3) overall pickling of the part

[0039] In order to ensure that the overall color of the part is uniform, the part is soaked in an acid solution at room temperature for 10s, and the formula and concentration of the acid solution are as follows: hydrofluoric acid (HF, 1.27) 60g / L, nitric acid (HNO3, 1.5) 350 / L, and the rest is water.

[0040] The liquid flow test results of the product after chemical polishing are as follows: oxidant path A 166.594MPa, fuel path B 139.759MPa, which meets the requirements.

[0041] Example 3

[0042] A chemical polishing method for a narrow channel inner cavity structure thrust device support, comprising:

[0043] Step (1) installation and water test of the tooling for the thrust device support, and the flow of the liquid outlet of the inner cavity channel is normal.

[0044] Step (2) injecting the chemical polishing solution into the inner cavity of the thrust device support.

[0045] The chemical polishing solution is injected into the inner cavity of the product at room temperature, and the chemical polishing solution comprises the following components: hydrofluoric acid (HF, 1.27) 80g / L, nitric acid (HNO3, 1.5) 90g / L and additives 0.2g / L, and the rest is water. The chemical polishing pump pressure is 0.4kg / cm 3 , and the chemical polishing time is 110s.

[0046] Step (3) overall pickling of the part

[0047] In order to ensure that the overall color of the part is uniform, the part is soaked in an acid solution at room temperature for 8s, and the formula and concentration of the acid solution are as follows: hydrofluoric acid (HF, 1.27) 40g / L, nitric acid (HNO3, 1.5) 370g / L, and the rest is water.

[0048] The liquid flow test results of the product after chemical polishing are as follows: oxidant path A 158.277MPa, fuel path B 138.587MPa, which meets the requirements.

[0049] The contents not described in detail in the specification of the present application are known to those skilled in the art.

[0050] Although the present application has been disclosed with reference to the preferred embodiments, it is not intended to limit the present application to the preferred embodiments. Any person skilled in the art, without departing from the spirit and scope of the present application, can make possible changes and modifications to the technical solutions of the present application by using the disclosed methods and technical contents. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application, without departing from the technical solutions of the present application, shall fall within the protection scope of the technical solutions of the present application.

Claims

1. A chemical finishing method for a narrow flow passage bore structure thrust device support characterized by, The method comprises the following steps: Water is tested in the inner cavity of the thrust device support to confirm normal flow; A chemical finishing solution is pumped into the inner cavity of the thrust device support to perform chemical finishing on the inner cavity, the chemical finishing solution comprising the following components: HF 60-80 g / L, HNO3 70-90 g / L, additive 0.2 g / L, and the rest being water; After chemical finishing, the whole thrust device support is subjected to chemical pickling, the chemical pickling solution comprising the following components: HF 40-60 g / L, HNO3 320-370 g / L, and the rest being water.

2. The chemical finishing method according to claim 1, characterized in that, The thrust device support is provided with an oxidant inlet A, a fuel inlet B and a gas inlet C, the three inlets are connected by a four-way joint, the remaining port of the four-way joint is connected with a pneumatic diaphragm pump to test water.

3. The chemical finishing method according to claim 1, characterized in that, The temperature of the chemical finishing solution is room temperature.

4. The chemical finishing method according to claim 1, characterized in that, Chemical finishing time is 90-120 s, pressure is 0.2-0.5 kg / cm 3 .

5. The chemical finishing method according to claim 1, characterized in that, The chemical pickling time is 5-10 s.

6. The chemical finishing method according to claim 1, characterized in that, The additive is sodium dodecyl sulfate.

7. A narrow flow passage bore structure thrust device support characterized by, The chemical finishing is performed by using the chemical finishing method according to any one of claims 1-6.

8. The narrow flow channel internal structure thrust device support of claim 7, wherein The narrow flow channel inner cavity structure thrust device support has an inner cavity with a minimum flow channel of only 0.2 mm.

9. The narrow flow channel internal structure thrust device support of claim 7, wherein The narrow flow channel inner cavity structure thrust device support is formed by additive manufacturing, and the surface roughness is as high as 10-15 μm.

10. The narrow flow channel internal structure thrust device support of claim 7, wherein The narrow flow channel inner cavity structure thrust device support has no risk of hydrogen embrittlement after chemical finishing.

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