Method for additive manufacturing and inner surface treatment of inner runner part

Abstract

The invention belongs to the technical field of additive manufacturing, and particularly relates to an additive manufacturing and inner surface treatment method for an inner runner part, which comprises the following steps of: preparing the inner runner part through an additive manufacturing technology according to an established CAD (Computer Aided Design) digital model; arranging a magnetic field outside the part; under the existence of an external magnetic field, the magnetic powder with the surface wrapped with the organic binder is fed into an inner runner of the part; pressurizing gas is injected into an inner runner of the part; removing a magnetic field arranged outside the part; the part is put into a heat treatment furnace to be heated; arranging a magnetic field outside the part; in the presence of an external magnetic field, feeding the magnetic needle into an inner runner of the part and enabling the magnetic needle to pass through the inner runner; repeating the steps for 3-5 times, and removing the external magnetic field; and pressurized gas is injected into the inner runner of the part, and the inner surface treatment of the part is completed. According to the method, the problem that the surface roughness of the complex inner runner in additive manufacturing is large can be remarkably solved.

Description

Technical Field

[0001] This invention belongs to the field of additive manufacturing technology, specifically relating to a method for additive manufacturing and internal surface treatment of internal flow channel parts. Background Technology

[0002] The "layer-by-layer manufacturing" characteristic of additive manufacturing results in distinct textured surfaces on additively manufactured parts, with surface roughness Ra typically exceeding 10 μm. The unique "step effect," "spheroidization effect," and "powder adhesion" inherent in additive manufacturing are the main factors contributing to the poor surface roughness of additively manufactured metal parts. While improving metal powder quality, optimizing the stacking direction, and refining process parameters can improve the surface quality of additively manufactured parts to some extent, they cannot completely solve the problem of surface roughness. Rough surfaces are prone to stress concentration, leading to the initiation of microcracks and significantly reducing the fatigue performance of the parts. Therefore, the surface of additively manufactured metal parts requires further processing to meet usage requirements.

[0003] Currently, the main surface treatment methods include machining, manual polishing, belt / wheel polishing, sandblasting, laser polishing, chemical polishing, electrochemical polishing, and abrasive flow polishing. However, the complex internal flow channels in additive manufacturing have limited space, and traditional methods for post-processing the surface of these channels suffer from poor accessibility, making it difficult to achieve ideal treatment results. Therefore, there is an urgent need to develop a post-processing method for complex internal flow channels in additive manufacturing to improve surface roughness and promote the wider application of additive manufacturing technology. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for additive manufacturing and internal surface treatment of internal flow channel parts, which can significantly improve the problem of large surface roughness in complex internal flow channels manufactured by additive manufacturing.

[0005] This invention provides a method for additive manufacturing and internal surface treatment of internal flow channel parts, comprising the following steps:

[0006] Step a: Establish a CAD digital model of the internal flow channel component;

[0007] Step b: Place the metal powder into the powder chamber of the additive manufacturing equipment, and manufacture the part using additive manufacturing technology based on the CAD digital model established in step a, to obtain the additively manufactured part;

[0008] Step c: Mix the organic binder with magnetic powder with a particle size of 5μm~10μm, so that the surface of the magnetic powder is coated with a layer of the organic binder;

[0009] Step d: Arrange a magnetic field outside the additively manufactured part;

[0010] Step e: After completing step d, in the presence of an external magnetic field, the magnetic powder processed in step c is fed into the inner flow channel of the additively manufactured part.

[0011] Step f: After completing step e, pressurized gas is injected into the inner flow channel of the additively manufactured part;

[0012] Step g: After completing step f, remove the magnetic field arranged outside the additively manufactured part;

[0013] Step h: After completing step g, place the additively manufactured part into a heat treatment furnace for heating;

[0014] Step i: After completing step h, arrange a magnetic field outside the additively manufactured part;

[0015] Step j: After completing step i, in the presence of an external magnetic field, insert the magnetic needle into the inner flow channel of the additively manufactured part and allow it to pass through the inner flow channel;

[0016] Step k: After repeating step j 3 to 5 times, remove the external magnetic field;

[0017] Step 1: After completing step k, pressurized gas is injected into the inner flow channel of the additively manufactured part to complete the inner surface treatment of the part.

[0018] In the method provided by the present invention, in step b, the material of the additively manufactured part includes, but is not limited to, GH3625 high-temperature alloy, TC4 titanium alloy or GH5188 high-temperature alloy.

[0019] In the method provided by the present invention, in step b, the inner flow channel diameter of the additively manufactured part is preferably 5-25 mm, specifically 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, 15 mm, 16 mm, 17 mm, 18 mm, 19 mm, 20 mm, 21 mm, 22 mm, 23 mm, 24 mm or 25 mm.

[0020] In the method provided by this invention, the purpose of using magnetic powder in step c is to form a dense metal with good bonding strength in the recessed area of ​​the original uneven surface of the inner flow channel. If the magnetic powder particle size is greater than 10 μm, it is difficult to fully fill the recessed area, resulting in poor improvement of the surface roughness of the inner flow channel. Simultaneously, powder with a particle size greater than 10 μm has poor sintering effect during the heating process in the subsequent step h, resulting in poor density, poor bonding strength, and easy peeling and flaking after sintering. Magnetic powder with a particle size less than 5 μm has poor flowability and is difficult to spray using a spray gun. Therefore, the magnetic powder particle size used is between 5 μm and 10 μm, specifically 5 μm, 5.5 μm, 6 μm, 6.5 μm, 7 μm, 7.5 μm, 8 μm, 8.5 μm, 9 μm, 9.5 μm, or 10 μm.

[0021] In the method provided by this invention, in step c, the magnetic powder is preferably 410 stainless steel magnetic powder and / or 430 stainless steel magnetic powder; the organic binder includes, but is not limited to, polyvinyl alcohol; the mass ratio of the magnetic powder to the organic binder is preferably 100:(0.05~0.5), specifically 100:0.05, 100:0.1, 100:0.15, 100:0.2, 100:0.25, 100:0.3, 100:0.35, 100:0.4, 100:0.45 or 100:0.5.

[0022] In the method provided by this invention, in step c, when mixing the magnetic powder and the organic binder, it is preferable to use two spray guns. One spray gun is loaded with magnetic powder, and the other spray gun is loaded with organic binder. While the magnetic powder is being sprayed out of the first spray gun, the organic binder is simultaneously sprayed onto the sprayed magnetic powder using the second spray gun. This approach allows the organic binder to uniformly coat the surface of the magnetic powder, promoting the formation of a dense, well-bonded metal during the heating process in the subsequent step h. Furthermore, this method is simple to operate, requires inexpensive equipment, and facilitates the widespread application of this invention.

[0023] In the method provided by this invention, there is no requirement for the order of step c with steps a and b.

[0024] In the method provided by this invention, in step d, the magnetic field preferably conforms to the shape of the inner flow channel of the additively manufactured part, covering the internal region of the inner flow channel. This ensures that in the subsequent step e, the magnetic powder is uniformly distributed inside the inner flow channel under the action of the magnetic field.

[0025] In the method provided by the present invention, in step e, the magnetic powder fed in can be uniformly covered on the surface of the inner flow channel by an external magnetic field, and these magnetic powders can form a metal that uniformly covers the surface of the inner flow channel during the heating process in the subsequent step h.

[0026] In the method provided by this invention, step f, injecting pressurized gas into the inner channel, is to use the mechanical compression of the gas to cause the magnetic powder to converge towards the recessed area of ​​the original uneven surface of the inner channel. Simultaneously, under the gas pressure, the magnetic powder coated with the binder can be fully bonded together, both between the magnetic powder and the surface of the inner channel. This ensures that after the subsequent heat treatment in step h, the magnetic powder forms a dense metal with good bonding strength in the recessed area of ​​the original uneven surface of the inner channel.

[0027] In the method provided by the present invention, in step f, the pressure of the pressurized gas is preferably 10~20MPa, specifically 10MPa, 11MPa, 12MPa, 13MPa, 14MPa, 15MPa, 16MPa, 17MPa, 18MPa, 19MPa or 20MPa.

[0028] In the method provided by this invention, in step f, the injection flow rate of the pressurized gas is preferably 13 L / min to 23 L / min, specifically 13 L / min, 14 L / min, 15 L / min, 16 L / min, 17 L / min, 18 L / min, 19 L / min, 20 L / min, 21 L / min, 22 L / min, or 23 L / min. When the gas flow rate is less than 13 L / min, the gas pressure is too low, making it difficult to achieve sufficient adhesion of the magnetic powder; when the gas flow rate is greater than 23 L / min, the excessive gas flow rate will blow the magnetic powder out of the inner channel, disrupting the uniformity of the magnetic powder coverage on the inner channel surface.

[0029] In the method provided by the present invention, in step f, the pressurized gas is preferably air and / or argon, which are inexpensive and readily available, thus facilitating the promotion and application of the method of the present invention.

[0030] In the method provided by this invention, in step g, the magnetic field is preferably removed from a direction parallel to the radial direction of the inner flow channel of the additively manufactured part. This method of magnetic field removal avoids the magnetic powder already covering the surface of the inner flow channel from shifting due to changes in the magnetic field during the magnetic field removal process, thus preventing damage to the uniformity of powder distribution and ensuring that the magnetic powder can form a uniform metal covering the surface of the inner flow channel during the heating process in the subsequent step h.

[0031] In the method provided by the present invention, in step h, by heat treatment, magnetic powder can be sintered in the concave area of ​​the original uneven surface of the inner channel to form a dense metal with good bonding strength, thereby improving the surface roughness by filling the concave area.

[0032] In the method provided by the present invention, the heating process in step h preferably includes: first heating from the ambient temperature to 50℃~80℃ and holding for 30min~60min; continuing to heat to 200℃~250℃ and holding for 50min~70min; then heating to 800℃~900℃ and holding for 120min~180min; and finally cooling with the furnace to the ambient temperature.

[0033] In the method provided by this invention, the specific heating process involved in step h is described as follows:

[0034] First, the temperature is raised from ambient temperature to 50℃~80℃ and held for 30min~60min. This is to allow the binder to fully volatilize and prevent the formation of porosity defects in the sintered metal. When the heating temperature is below 50℃, the binder volatilizes slowly and inefficiently, resulting in incomplete volatilization. When the heating temperature is above 80℃, the binder volatilizes too quickly, easily forming porosity defects and compromising the density of the sintered metal. Therefore, the preferred heating temperature is between 50℃ and 80℃, specifically 50℃, 55℃, 60℃, 65℃, 70℃, 75℃, or 80℃. Holding time less than 30min results in insufficient binder volatilization. Holding time greater than 60min does not significantly increase the binder volatilization effect but instead prolongs the processing time and reduces production efficiency. Therefore, the preferred holding time is between 30min and 60min, specifically 30min, 35min, 40min, 45min, 50min, 55min, or 60min. After the initial heat treatment, the temperature is further increased to 200℃~250℃ and held for 50min~70min. This is to allow the magnetic powder to pre-sinter, reducing thermal stress during sintering and preventing cracking and spalling of the sintered metal. If the heating temperature is below 200℃, the growth kinetics of the magnetic powder are insufficient, resulting in insignificant sintering. If the heating temperature is above 250℃, the powder growth rate is too rapid, leading to excessive thermal stress during sintering and making the sintered metal prone to cracking and spalling. Therefore, the preferred heating temperature is between 200℃ and 250℃, specifically 200℃, 205℃, 210℃, 215℃, 220℃, 225℃, 230℃, 235℃, 240℃, 245℃, or 250℃. Holding time less than 50min results in insignificant pre-sintering of the magnetic powder. Holding time exceeding 70 minutes does not significantly improve the pre-sintering effect of the magnetic powder; instead, it prolongs the processing time and reduces production efficiency. Therefore, the holding time is preferably between 50 and 70 minutes, specifically 50, 55, 60, 65, or 70 minutes. After the second heating treatment, the temperature is further increased to 800℃~900℃ and held for 120 to 180 minutes. This is to allow the magnetic powder to form a dense metal through sintering. If the heating temperature is below 800℃, the growth kinetics of the magnetic powder are insufficient, resulting in an insignificant sintering effect. If the heating temperature is above 900℃, the temperature is too high, causing rapid grain growth in the sintered metal, leading to performance degradation. Therefore, the heating temperature is preferably between 800℃ and 900℃, specifically 800℃, 810℃, 820℃, 830℃, 840℃, 850℃, 860℃, 870℃, 880℃, 890℃, or 900℃. When the holding time is less than 120 minutes, the sintering effect of the magnetic powder is not obvious.Holding times exceeding 180 minutes do not significantly improve the sintering effect of magnetic powder; instead, they prolong the processing time and reduce production efficiency. Therefore, the optimal holding time is between 120 and 180 minutes, specifically 120, 130, 140, 150, 160, 170, or 180 minutes. Cooling the furnace to ambient temperature after heating is to achieve a slow cooling effect, allowing thermal stress to be released gradually and preventing cracking and spalling of the sintered metal.

[0035] In the method provided by this invention, in step i, the magnetic field conforms to the shape of the inner flow channel of the additively manufactured part, covering the internal region of the inner flow channel. This ensures that in the subsequent step j, the magnetic needle passes uniformly through the inner flow channel under the influence of the magnetic field.

[0036] In the method provided by the present invention, in step j, a magnetic needle is attracted into and passes through the inner flow channel. The purpose of doing so is to further reduce the small height difference between the sintered metal and the original uneven surface of the inner flow channel by the mechanical scraping action between the magnetic needle and the surface of the inner flow channel, thereby improving the surface roughness of the inner flow channel.

[0037] In the method provided by the present invention, in step j, the magnetic needle is preferably an iron oxide magnetic needle.

[0038] In the method provided by this invention, in step j, if the diameter of the magnetic needle is less than 0.5 mm, the processing difficulty of the magnetic needle is too great, which is detrimental to the use of this invention. If the diameter of the magnetic needle is greater than 1.5 mm, it is difficult to enter the small inner flow channel, and the processing effect is limited. Therefore, the diameter of the magnetic needle is preferably between 0.5 mm and 1.5 mm, specifically 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, or 1.5 mm. If the length of the magnetic needle is less than 3 mm, the processing difficulty of the magnetic needle is too great, which is detrimental to the use of this invention. If the length of the magnetic needle is greater than 10 mm, it is difficult to enter the small inner flow channel, and the processing effect is limited. Therefore, the length of the magnetic needle is preferably between 3 mm and 10 mm, specifically 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, or 10 mm.

[0039] In the method provided by this invention, in step k, step j is repeated 3 to 5 times in order to fully exert the mechanical scraping effect of the magnetic needle. If the number of repetitions is less than 3 times, the best removal effect cannot be achieved. If the number of repetitions is more than 5 times, the processing effect cannot be significantly increased. Instead, it prolongs the time and reduces production efficiency.

[0040] In the method provided by this invention, in step k, the magnetic field is preferably removed from a direction parallel to the axial direction of the flow channel within the additively manufactured part. This method of magnetic field removal can effectively remove the magnetic needle, avoiding any residue.

[0041] In the method provided by this invention, in step 1, injecting pressurized gas into the inner flow channel is to further clean up any debris, magnetic needles, or other excess material that may remain inside the inner flow channel.

[0042] In the method provided by the present invention, in step 1, the pressure of the pressurized gas is preferably 10~20MPa, specifically 10MPa, 11MPa, 12MPa, 13MPa, 14MPa, 15MPa, 16MPa, 17MPa, 18MPa, 19MPa or 20MPa.

[0043] In the method provided by this invention, in step 1, when the gas flow rate is less than 6 L / min, the airflow is insufficient and the cleaning effect is poor. When the gas flow rate is greater than 16 L / min, the gas consumption increases, but it does not significantly increase the cleaning effect; instead, it leads to increased gas usage costs. Therefore, the injection flow rate of the pressurized gas is preferably between 6 L / min and 16 L / min, specifically 6 L / min, 7 L / min, 8 L / min, 9 L / min, 10 L / min, 11 L / min, 12 L / min, 13 L / min, 14 L / min, 15 L / min, or 16 L / min.

[0044] In the method provided by the present invention, in step 1, the pressurized gas is preferably air and / or argon, which are inexpensive and readily available, thus facilitating the promotion and application of the method of the present invention.

[0045] Compared with the prior art, the beneficial effects of the present invention are: under the synergistic effect of multiple physical fields such as magnetic field, high-pressure airflow, and thermal field, it has better accessibility when processing the surface of complex internal flow channels in additive manufacturing, and can effectively improve the surface roughness of the internal surface. Detailed Implementation

[0046] The technical solution of the present invention is described below with reference to specific implementation schemes. However, those skilled in the art will understand that the embodiments described below are only some embodiments of the present invention, not all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall be followed. Where the manufacturers of reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0047] Example 1

[0048] This embodiment provides an additive manufacturing and internal surface treatment method for GH3625 high-temperature alloy fuel injector rods, including the following steps:

[0049] 1) Establish a CAD digital model of the GH3625 high-temperature alloy fuel injector rod, which has a complex internal flow channel with a diameter of 6mm.

[0050] 2) Place GH3625 high-temperature alloy powder into the powder chamber of the laser selective melting additive manufacturing equipment, and complete the laser selective melting additive manufacturing of the fuel injector based on the established CAD digital model.

[0051] 3) Load 410 stainless steel magnetic powder (7μm particle size) into one spray gun and polyvinyl alcohol organic binder into another spray gun. While spraying the magnetic powder out of the spray gun, use the other spray gun to spray the organic binder onto the sprayed magnetic powder so that the surface of the magnetic powder is coated with a layer of organic binder. The amount of organic binder is 0.2% of the mass of the magnetic powder.

[0052] 4) Arrange a magnetic field outside the fuel injector, the magnetic field covering the inner flow channel area of ​​the fuel injector and having the same shape as the inner flow channel.

[0053] 5) Pour 410 stainless steel powder coated with adhesive into one end of the fuel injector's inner channel. The powder is attracted into the inner channel by an external magnetic field and covers the surface of the inner channel under the action of the magnetic field.

[0054] 6) High-pressure argon gas with a pressure of 15MPa is introduced from one end of the inner flow channel of the fuel injector rod, and the gas flow rate is 13L / min.

[0055] 7) Remove the external magnetic field from the direction parallel to the radial direction of the fuel injector's inner flow channel.

[0056] 8) Place the fuel injection rod into the heat treatment furnace for heating. First, heat it from room temperature to 50°C and hold it for 60 minutes; then continue heating to 250°C and hold it for 50 minutes; then heat it to 900°C and hold it for 120 minutes; finally, cool it to room temperature with the furnace.

[0057] 9) Arrange a magnetic field outside the fuel injector rod, the magnetic field covering the inner flow channel area of ​​the fuel injector rod and having the same shape as the inner flow channel.

[0058] 10) Pour an iron oxide magnetic needle with a diameter of 0.5 mm and a length of 10 mm into one end of the fuel injector's inner channel. Under the action of an external magnetic field, it passes through the fuel injector's inner channel and leaves from the other end.

[0059] 11) After repeating the previous step 5 times, remove the external magnetic field from the direction parallel to the inner flow channel of the fuel injector.

[0060] 12) High-pressure argon gas at 15MPa is introduced into one end of the inner flow channel of the fuel injector at a flow rate of 6L / min. After no residues, debris or other impurities are blown out, the gas supply is stopped, and the inner surface treatment of the additive manufacturing fuel injector is completed.

[0061] The surface roughness of the inner flow channel of the additively manufactured fuel injector obtained in this embodiment was measured using a roughness tester. The surface roughness was Ra3.2μm, which is a significant improvement compared with the surface roughness Ra10.5μm before treatment using the method of the present invention.

[0062] Example 2

[0063] This embodiment provides an additive manufacturing and internal surface treatment method for a TC4 titanium alloy control housing, including the following steps:

[0064] 1) Establish a CAD digital model of the TC4 titanium alloy control housing, which has a complex internal flow channel with a diameter of 10 mm.

[0065] 2) Place TC4 titanium alloy powder into the powder chamber of the laser selective melting additive manufacturing equipment, and complete the laser selective melting additive manufacturing of the control shell based on the established CAD digital model.

[0066] 3) Load 430 stainless steel magnetic powder (particle size 10μm) into one spray gun and polyvinyl alcohol organic binder into another spray gun. While spraying the magnetic powder out of the spray gun, use the other spray gun to spray the organic binder onto the sprayed magnetic powder so that the surface of the magnetic powder is coated with a layer of organic binder. The amount of organic binder is 0.2% of the mass of the magnetic powder.

[0067] 4) Arrange a magnetic field outside the control housing, covering the inner flow channel area of ​​the control housing and conforming to the shape of the inner flow channel.

[0068] 5) Pour 430 stainless steel powder coated with adhesive into one end of the inner channel of the control housing. The powder is attracted into the inner channel by an external magnetic field and covers the surface of the inner channel under the action of the magnetic field.

[0069] 6) High-pressure argon gas with a pressure of 15MPa is introduced from one end of the flow channel inside the control housing, and the gas flow rate is 23L / min.

[0070] 7) Remove the external magnetic field from the direction parallel to the radial direction of the flow channel inside the control housing.

[0071] 8) Place the control housing into a heat treatment furnace for heating. First, heat it from room temperature to 80°C and hold for 30 minutes; then continue heating to 200°C and hold for 70 minutes; then heat it to 800°C and hold for 180 minutes; finally, cool it to room temperature with the furnace.

[0072] 9) Arrange a magnetic field outside the control housing, the magnetic field covering the inner flow channel area of ​​the control housing and conforming to the shape of the inner flow channel.

[0073] 10) Pour an iron oxide magnetic needle with a diameter of 1.5 mm and a length of 3 mm into one end of the flow channel inside the control housing. Under the action of an external magnetic field, it passes through the flow channel inside the control housing and leaves from the other end.

[0074] 11) After repeating the previous step 3 times, remove the external magnetic field from the direction parallel to the flow channel inside the control housing.

[0075] 12) High-pressure argon gas with a pressure of 15MPa is introduced from one end of the flow channel inside the control housing at a flow rate of 16L / min. After no residues, debris or other impurities are blown out, the gas supply is stopped, and the post-processing of the flow channel surface inside the additive manufacturing control housing is completed.

[0076] The surface roughness of the inner flow channel of the additive manufacturing control housing obtained in this embodiment was measured using a roughness tester. The surface roughness was Ra3.6μm, which is a significant improvement compared with the surface roughness Ra11.7μm before treatment using the method of the present invention.

[0077] Example 3

[0078] This embodiment provides an additive manufacturing and internal surface treatment method for the GH5188 high-temperature alloy flame stabilizer, including the following steps:

[0079] 1) Establish a CAD digital model of the GH5188 high-temperature alloy flame stabilizer, which has a complex internal flow channel with a diameter of 20mm.

[0080] 2) Place GH5188 high-temperature alloy powder into the powder chamber of the laser selective melting additive manufacturing equipment, and complete the laser selective melting additive manufacturing of the flame stabilizer based on the established CAD digital model.

[0081] 3) Load 410 stainless steel magnetic powder (particle size 5μm) into one spray gun and polyvinyl alcohol organic binder into another spray gun. While spraying the magnetic powder out of the spray gun, use the other spray gun to spray the organic binder onto the sprayed magnetic powder so that the surface of the magnetic powder is coated with a layer of organic binder. The amount of organic binder is 0.2% of the mass of the magnetic powder.

[0082] 4) Arrange a magnetic field outside the flame stabilizer, the magnetic field covering the inner flow channel area of ​​the flame stabilizer and having the same shape as the inner flow channel.

[0083] 5) Pour 410 stainless steel powder coated with binder into one end of the inner channel of the flame stabilizer. The powder is attracted into the inner channel by an external magnetic field and covers the surface of the inner channel under the action of the magnetic field.

[0084] 6) High-pressure argon gas with a pressure of 15MPa is introduced from one end of the flow channel inside the flame stabilizer, and the gas flow rate is 16L / min.

[0085] 7) Remove the external magnetic field from the direction parallel to the radial direction of the inner flow channel of the flame stabilizer.

[0086] 8) Place the flame stabilizer in a heat treatment furnace for heating. First, heat it from room temperature to 70°C and hold for 50 minutes; then continue heating to 230°C and hold for 65 minutes; then heat it to 860°C and hold for 150 minutes; finally, cool it to room temperature with the furnace.

[0087] 9) Arrange a magnetic field outside the flame stabilizer, the magnetic field covering the inner flow channel area of ​​the flame stabilizer and having the same shape as the inner flow channel.

[0088] 10) Pour an iron oxide magnetic needle with a diameter of 1 mm and a length of 6 mm into one end of the flow channel inside the flame stabilizer. Under the action of an external magnetic field, it passes through the flow channel inside the flame stabilizer and leaves from the other end.

[0089] 11) After repeating the previous step 4 times, remove the external magnetic field from the direction parallel to the flow channel inside the flame stabilizer.

[0090] 12) High-pressure argon gas with a pressure of 15MPa is introduced into one end of the inner channel of the flame stabilizer at a flow rate of 11L / min. After no residues, debris or other impurities are blown out, the gas supply is stopped to complete the inner surface treatment of the additive manufacturing flame stabilizer.

[0091] The surface roughness of the inner channel of the additively manufactured flame stabilizer obtained in this embodiment was measured using a roughness tester. The surface roughness was Ra3.4μm, which is a significant improvement compared with the surface roughness Ra10.3μm before treatment using the method of the present invention.

[0092] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for additive manufacturing and internal surface treatment of an internal flow channel component, characterized in that, Includes the following steps: Step a: Establish a CAD digital model of the internal flow channel component; Step b: Place the metal powder into the powder chamber of the additive manufacturing equipment, and manufacture the part using additive manufacturing technology based on the CAD digital model established in step a, to obtain the additively manufactured part; Step c: Mix the organic binder with magnetic powder with a particle size of 5μm~10μm, so that the surface of the magnetic powder is coated with a layer of the organic binder; Step d: Arrange a magnetic field outside the additively manufactured part; Step e: After completing step d, in the presence of an external magnetic field, the magnetic powder processed in step c is fed into the inner flow channel of the additively manufactured part. Step f: After completing step e, pressurized gas is injected into the inner flow channel of the additively manufactured part; Step g: After completing step f, remove the magnetic field arranged outside the additively manufactured part; Step h: After completing step g, place the additively manufactured part into a heat treatment furnace for heating; Step i: After completing step h, arrange a magnetic field outside the additively manufactured part; Step j: After completing step i, in the presence of an external magnetic field, insert the magnetic needle into the inner flow channel of the additively manufactured part and allow it to pass through the inner flow channel; Step k: After repeating step j 3 to 5 times, remove the external magnetic field; Step 1: After completing step k, pressurized gas is injected into the inner flow channel of the additively manufactured part to complete the inner surface treatment of the part.

2. The method according to claim 1, characterized in that, In step c, when the magnetic powder and the organic binder are mixed, two spray guns are used. One spray gun is loaded with magnetic powder and the other spray gun is loaded with organic binder. While the magnetic powder is being sprayed out of the spray gun, the organic binder is sprayed onto the sprayed magnetic powder using the other spray gun.

3. The method according to claim 1, characterized in that, In step d, the magnetic field is consistent with the shape of the inner flow channel of the additively manufactured part and covers the inner region of the inner flow channel.

4. The method according to claim 1, characterized in that, In step f, the pressurized gas is air and / or argon; the injection flow rate of the pressurized gas is 13 L / min to 23 L / min.

5. The method according to claim 1, characterized in that, In step g, the magnetic field is removed from a direction parallel to the radial direction of the internal flow channel of the additively manufactured part.

6. The method according to claim 1, characterized in that, In step h, the heating process specifically includes: first heating from ambient temperature to 50℃~80℃ and holding for 30min~60min; continuing to heat to 200℃~250℃ and holding for 50min~70min; then heating to 800℃~900℃ and holding for 120min~180min; and finally cooling with the furnace to ambient temperature.

7. The method according to claim 1, characterized in that, In step i, the magnetic field is consistent with the shape of the inner flow channel of the additively manufactured part and covers the inner region of the inner flow channel.

8. The method according to claim 1, characterized in that, In step j, the diameter of the magnetic needle is 0.5mm to 1.5mm and the length is 3mm to 10mm.

9. The method according to claim 1, characterized in that, In step k, the magnetic field is removed from a direction parallel to the axial direction of the flow channel inside the additively manufactured part.

10. The method according to claim 1, characterized in that, In step 1, the pressurized gas is air and / or argon; the injection flow rate of the pressurized gas is 6 L / min to 16 L / min.