A method for preparing complex thin-walled parts using dynamic multi-dimensional control technology

Abstract

The present invention belongs to the field of powder metallurgy technology, and relates to a method for preparing complex thin-walled parts using dynamic multi-dimensional control technology, comprising the following steps: designing and preparing a control mold; cleaning the control mold and completing the assembly and fixation of the control mold; placing the assembled and fixed control mold into a prefabricated sleeve, and performing powder filling and degassing and sealing treatment under vacuum conditions; performing hot isostatic pressing on the entire prefabricated sleeve after the degassing and sealing treatment, removing the prefabricated sleeve and the control mold after the hot isostatic pressing treatment to obtain a target part blank; and heat-treating the target part blank to obtain a target part. The preparation method of the present invention can form complex thin-walled parts in one go, and achieve precise control of the parts. After forming, the target part only needs to machine the assembly surface to meet the use requirements, which reduces the amount of forming processing and effectively reduces the manufacturing cost.

Description

Technical Field

[0001] The invention belongs to the technical field of powder metallurgy and relates to a method for preparing complex thin-walled parts by utilizing dynamic multi-dimensional control technology. Background Art

[0002] Complex thin-walled parts, core components in aerospace equipment, are characterized by thin walls, large volumes, and complex features. Some of these parts have a minimum thickness of only 1 mm. Using conventional hot isostatic pressing (HIP) densification methods, the cladding's poor rigidity and tendency to deform make it difficult to control the final product's shape.

[0003] In addition, complex thin-walled parts include many typical characteristic structures such as mounting grooves, observation holes and bosses. According to conventional methods, they can only be prepared by first increasing the allowance for densification and then performing machining. However, this method is quite difficult in the later processing and cannot achieve stable large-scale production.

[0004] In view of this, this invention is proposed. Summary of the Invention

[0005] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and propose a method for preparing complex thin-walled parts using dynamic multi-dimensional control technology. This method can form complex thin-walled parts in one go and can accurately control the shape. After forming, only the assembly surface needs to be machined to meet the use requirements. It solves the problem that thin-walled complex parts are difficult to accurately control during hot isostatic pressing and the amount of processing after forming is large. This method can shorten the manufacturing cycle while effectively reducing manufacturing costs.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] The present invention provides a method for preparing complex thin-walled parts using dynamic multi-dimensional control technology, comprising the following steps:

[0008] Step 1: Design and prepare the control mold according to the target part shape;

[0009] Step 2: After cleaning the control mold prepared in step 1, assemble and fix the control mold;

[0010] Step 3: Place the control mold assembled and fixed in step 2 into the prefabricated package;

[0011] Step 4: Under vacuum conditions, first load the alloy powder into the prefabricated package with the controlled mold in step 3. After the powder is loaded, the prefabricated package is degassed and sealed;

[0012] Step 5: first, hot isostatic pressing the entire prefabricated package after the degassing and sealing treatment in step 4, and then remove the prefabricated package and the control mold to obtain the target part blank;

[0013] Step 6: heat-treating the target part blank obtained in step 5 to obtain the target part.

[0014] Furthermore, in step 1, the control mold includes a mold base, a mold shell and an inner mold core, the middle portion of the mold base is fixedly connected to the inner mold core, a sliding track is provided on the mold base, the mold shell is a split structure, located outside the inner mold core, and a groove is provided at the bottom of the mold shell to slide with the sliding track;

[0015] When using the investment casting process to prepare the control mold, low-temperature solid phase sintering is required. The sintering temperature is: 1000℃~1050℃, and the sintering time is: 6h~8h.

[0016] Furthermore, the material of the control mold is a mixture of Al2O3 and SiO2, wherein the mass ratio of Al2O3 to SiO2 is 3~5:1.

[0017] Furthermore, in step 3, the prefabricated sheath is a stainless steel sheath.

[0018] Furthermore, in step 4, at a vacuum degree of ≤1×10 -2 Under the condition of Pa, the alloy powder is loaded into a prefabricated sleeve with a controlled mold. During the powder loading process, the prefabricated sleeve needs to be vibrated with a vibration frequency of 70Hz~90Hz and an amplitude of 0.5mm~1mm.

[0019] Furthermore, after the vibration treatment, the density of the alloy powder in the prefabricated sheath is 65% to 75%.

[0020] Furthermore, in step 4, the degassing temperature in the degassing and sealing treatment is 500°C to 600°C; after the degassing and sealing treatment, the prefabricated package is tested for airtightness, and the leakage rate is ≤1×10 -10 Pa·m 3 / s.

[0021] Furthermore, in step 5, the temperature of the hot isostatic pressing treatment is: 900° C.~950° C., the heat preservation and pressure holding time is: 2h~3h, and the pressure is: 120MPa~140MPa.

[0022] Furthermore, in step 5, the density of the target workpiece blank is: 100%.

[0023] Furthermore, during the hot isostatic pressing process in step 5, the mold shell of the control mold slides and contracts inward along the sliding track provided on the mold base under the action of pressure.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention uses a high-strength control mold prepared by an investment casting process to perform hard control on the target part. During the densification process, the control mold does not shrink or deform, and can realize the integrated hot isostatic pressing of complex thin-walled parts, avoiding the problem of local insufficient size caused by the uncontrollable shrinkage law of carbon steel or stainless steel cores; and the control mold material used in the present invention is a mixture of Al2O3 and SiO2, which is sintered at a relatively low temperature, so that the control mold has a certain strength but is not completely dense, and the Al2O3 and SiO2 mixture does not react with the target part material, making it easy to remove; the final integrated part greatly reduces the difficulty of subsequent processing and turning allowance, and can be stably produced in large quantities. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The accompanying drawings are incorporated in and constitute a part of this specification and, together with the description, serve to explain the principles of the invention.

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0028] Figure 1 A flow chart of the method for preparing complex thin-walled parts using dynamic multi-dimensional control technology provided by the present invention;

[0029] Figure 2 A schematic diagram of the structure of the assembled mold prepared by the present invention;

[0030] Figure 3 This is a real picture of a casing prepared by the method of the present invention;

[0031] Among them, 1-mold base; 2-mold shell; 3-internal mold core. DETAILED DESCRIPTION

[0032] Here, exemplary embodiments will be described in detail, and the embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are only examples consistent with some aspects of the present invention described in detail in the appended claims.

[0033] The present invention provides a method for preparing complex thin-walled parts using dynamic multi-dimensional control technology, such as Figure 1 As shown, the following steps are included:

[0034] Step 1: Design and prepare the control mold using dynamic multi-dimensional control technology according to the target part shape.

[0035] Specifically, if Figure 2 As shown, the control mold comprises a mold base 1, a mold shell 2, and an internal core 3. The internal core 3 is fixedly connected to the center of the mold base 1. Two transverse, parallel sliding rails are provided on the mold base 1. The mold shell 2 is a split structure, located outside the internal core 3. A groove is provided at the bottom of the mold shell 2 to mate with the sliding rails. The control mold is made of a mixture of Al2O3 and SiO2, with a mass ratio of Al2O3 to SiO2 of 3 to 5:1. When manufacturing the control mold using the investment casting process, low-temperature solid-phase sintering is required to enhance its strength. The sintering temperature is between 1000°C and 1050°C, and the sintering time is between 6 and 8 hours. The Al2O3 and SiO2 mixture sintered at a relatively low temperature exhibits a certain strength but is not completely dense. Furthermore, the Al2O3 and SiO2 mixture does not react with the part material, making it easy to remove. The present invention adopts the investment casting process to prepare the control mold most simply, and other casting processes can also be used to prepare the control mold.

[0036] Step 2: After cleaning the inner cavity of the control mold prepared in step 1, assemble and fix the control mold.

[0037] Specifically, after the control mold is prepared, it is necessary to clean the impurities and dust in the inner cavity of the control mold, and then place the split control mold in a fixed position; the inner cavity of the control mold is: the inner cavity formed by the upper surface of the mold base 1, the inner surface of the mold shell 2, and the outer surface of the inner fixed core 3 after assembly and fixation. Figure 2 As shown, an internal molding core 3 is placed in the middle of the mold base 1, and the interface design of the split-type control mold is a snap-on type. Correspondingly, after the groove at the bottom of the split-type mold shell 2 is matched with the sliding track provided on the mold base 1 and placed, the split-type mold shell 2 is snap-on to complete the assembly.

[0038] Step 3: Place the control mold assembled and fixed in step 2 into a prefabricated sleeve, which is a stainless steel sleeve.

[0039] Step 4: Under vacuum conditions, first load the alloy powder into the prefabricated package with the controlled mold in step 3. After the powder loading is completed, the entire prefabricated package is degassed and sealed.

[0040] Specifically, at a vacuum degree of ≤1×10-2 Under the conditions of Pa, the alloy powder is first loaded into a prefabricated sleeve with a controlled mold. During the powder loading process, the prefabricated sleeve is vibrated with a vibration frequency of 70Hz~90Hz and an amplitude of 0.5mm~1mm. After the vibration treatment, the density of the alloy powder in the prefabricated sleeve is 65%~75%. Then, a degassing and sealing treatment is carried out, wherein the degassing temperature is 500℃~600℃; after the degassing and sealing treatment is completed, the entire prefabricated sleeve is tested for airtightness, and the leakage rate needs to be ≤1×10 -10 Pa·m 3 / s. The prefabricated packages in this step are all prefabricated packages with a controlled mold.

[0041] Specifically, the alloy powder is determined by the target product to be formed in the end, and high-temperature alloy powder or titanium alloy powder can be used.

[0042] Step 5: first perform hot isostatic pressing on the entire prefabricated package that has been degassing and sealing in step 4, then remove the prefabricated package and the control mold to obtain the target part blank.

[0043] Specifically, the HIP process is performed at a temperature of 900°C to 950°C, with a holding time of 2 to 3 hours and a pressure of 120 MPa to 140 MPa. During the HIP process, the control die contracts inward under pressure along a sliding track at the bottom of the preformed can, achieving powder densification and precise shape control. After HIP, the target part density is 100%.

[0044] Step 6: heat-treating the target part blank obtained in step 5 to obtain the target part.

[0045] Specifically, the heat treatment in the present invention adopts a standard heat treatment system. Different alloys correspond to different standard heat treatment systems. The corresponding standard heat treatment system is selected based on the alloy to be finally formed.

[0046] By using the method for preparing complex thin-walled parts with dynamic multi-dimensional control provided by the present invention, thin-walled parts with various complex structures can be prepared.

[0047] In order to verify the beneficial effects of the preparation method of the present invention, the following examples are provided to further illustrate the effects. Example 1

[0048] This embodiment provides a method for preparing complex thin-walled parts using dynamic multi-dimensional control technology, which specifically includes the following steps:

[0049] Step 1: Design and prepare a control mold according to the shape of the target part. The material of the control mold is a mixture of Al2O3 and SiO2, where the mass ratio of Al2O3 to SiO2 is 3:1. The control mold prepared by the investment casting process is subjected to low-temperature solid-phase sintering at a sintering temperature of 1050°C and a sintering time of 8 hours.

[0050] Step 2: After cleaning the inner cavity of the control mold prepared in step 1, assemble and fix the control mold.

[0051] Step 3: Place the control mold assembled and fixed in step 2 into the prefabricated package.

[0052] Step 4: At a vacuum degree of ≤1×10 -2 Pa, first load the alloy powder into the prefabricated sleeve with the control mold in step 3. During the powder loading process, the prefabricated sleeve is vibrated with a vibration frequency of 90 Hz and an amplitude of 0.5 mm. After the vibration treatment, the density of the alloy powder in the prefabricated sleeve is 75%. After the powder loading is completed, the prefabricated sleeve is degassed and sealed, wherein the degassing temperature is 600 ° C; after the degassed and sealed treatment, the entire prefabricated sleeve is tested for airtightness, and the leakage rate needs to be ≤1×10 -10 Pa·m 3 / s.

[0053] Step 5: Hot isostatic pressing (HIP) the entire prefabricated casing, which has undergone degassing and sealing treatment in Step 4, is then removed from the casing and control mold to obtain the target part. The HIP temperature is 900°C, the holding time is 3 hours, and the pressure is 140 MPa. The target part density is 100%.

[0054] Step 6: Heat-treat the target part blank obtained in step 5 according to a standard heat treatment system to obtain the target part. Example 2

[0055] This embodiment provides a method for preparing complex thin-walled parts using dynamic multi-dimensional control technology, which specifically includes the following steps:

[0056] Step 1: Design and prepare a control mold according to the shape of the target part. The material of the control mold is a mixture of Al2O3 and SiO2, where the mass ratio of Al2O3 to SiO2 is 4:1. The control mold prepared by the investment casting process is subjected to low-temperature solid-phase sintering at a sintering temperature of 1025°C and a sintering time of 7 hours.

[0057] Step 2: After cleaning the inner cavity of the control mold prepared in step 1, assemble and fix the control mold.

[0058] Step 3: Place the control mold assembled and fixed in step 2 into the prefabricated package.

[0059] Step 4: At a vacuum degree of ≤1×10 -2 Pa, first load the alloy powder into the prefabricated sleeve with the control mold in step 3. During the powder loading process, the prefabricated sleeve is vibrated with a vibration frequency of 80 Hz and an amplitude of 0.75 mm. After the vibration treatment, the density of the alloy powder in the prefabricated sleeve is 70%. After the powder loading is completed, the prefabricated sleeve is degassed and sealed, wherein the degassing temperature is 550 ° C; after the degassed and sealed treatment, the entire prefabricated sleeve is tested for airtightness, and the leakage rate needs to be ≤1×10 -10 Pa·m 3 / s.

[0060] Step 5: Hot isostatic pressing (HIP) is performed on the entire prefabricated casing, which has undergone degassing and sealing treatment in Step 4. The casing and control mold are then removed to obtain the target part blank. The HIP temperature is 925°C, the holding time is 2.5 hours, and the pressure is 130 MPa. The target part blank has a density of 100%.

[0061] Step 6: Heat-treat the target part blank obtained in step 5 according to a standard heat treatment system to obtain the target part. Example 3

[0062] This embodiment provides a method for preparing complex thin-walled parts using dynamic multi-dimensional control technology, which specifically includes the following steps:

[0063] Step 1: Design and prepare the control mold according to the shape of the target part. The material of the control mold is a mixture of Al2O3 and SiO2, where the mass ratio of Al2O3 to SiO2 is 5:1. When the control mold is prepared by the investment casting process, low-temperature solid-phase sintering is performed at a sintering temperature of 1000°C and a sintering time of 6 hours.

[0064] Step 2: After cleaning the inner cavity of the control mold prepared in step 1, assemble and fix the control mold.

[0065] Step 3: Place the control mold assembled and fixed in step 2 into the prefabricated package.

[0066] Step 4: At a vacuum degree of ≤1×10 -2Pa, first load the alloy powder into the prefabricated sleeve with the control mold in step 3. During the powder loading process, the prefabricated sleeve is vibrated with a vibration frequency of 70 Hz and an amplitude of 1 mm. After the vibration treatment, the density of the alloy powder in the prefabricated sleeve is 65%. After the powder loading is completed, the prefabricated sleeve is degassed and sealed at a temperature of 500 ° C. After the degassed and sealed treatment, the entire prefabricated sleeve is tested for airtightness, and the leakage rate needs to be ≤1×10 -10 Pa·m 3 / s.

[0067] Step 5: Hot isostatic pressing (HIP) the entire prefabricated casing, which has undergone degassing and sealing treatment in Step 4, is then removed from the casing and control mold to obtain the target part. The HIP temperature is 950°C, the holding time is 2 hours, and the pressure is 120 MPa. The target part density is 100%.

[0068] Step 6: Heat-treat the target part blank obtained in step 5 according to a standard heat treatment system to obtain the target part.

[0069] According to an embodiment of the present invention, Figure 3 As shown, the present invention also provides a real picture of a casing prepared by the method of the present invention. It is only necessary to open a structure with the casing boss shown in the figure on the mold shell 2 provided by the present invention to obtain a casing component with a boss integrally formed on the outside.

[0070] According to an embodiment of the present invention, a method for preparing complex thin-walled parts using dynamic multi-dimensional control technology is provided by the present invention. Hard control is performed using a high-strength control mold. The control mold can achieve multi-dimensional radial movement within a prefabricated sleeve, thereby solving the molding problem of complex thin-walled parts. The high-strength mold prepared by the present invention using the investment casting method, the mold shell 2 and the internal mold core 3 contain all the geometric features of the final part. The bottom of the mold base 1 is provided with a sliding track. During the hot isostatic pressing process, the mold shell 2 slides inward along the sliding track, while the internal mold core 3 is fixed, thereby extruding the alloy powder to achieve densification, thereby realizing the hot isostatic pressing integrated molding of complex thin-walled parts.

[0071] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0072] It should be understood that the present invention is not limited to the above description and that various modifications and changes may be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing complex thin-walled parts using dynamic multi-dimensional control technology, characterized in that: The steps include: Step 1: Design and prepare a control mold according to the shape of the target workpiece; the control mold includes a mold base (1), a mold shell (2) and an inner mold core (3); the middle part of the mold base (1) is fixedly connected to the inner mold core (3); a sliding track is provided on the mold base (1); the mold shell (2) is a split structure and is located outside the inner mold core (3); a groove is provided at the bottom of the mold shell (2) for sliding in cooperation with the sliding track; Step 2: After cleaning the control mold prepared in step 1, assemble and fix the control mold; Step 3: Place the control mold assembled and fixed in step 2 into the prefabricated package; Step 4: Under vacuum conditions, first load the alloy powder into the prefabricated package with the controlled mold in step 3. After the powder is loaded, the prefabricated package is degassed and sealed; Step 5: first, hot isostatic pressing the entire prefabricated package after the degassing and sealing treatment in step 4, and then remove the prefabricated package and the control mold to obtain the target part blank; During the hot isostatic pressing process, the mold shell (2) of the control mold slides inward and contracts along the sliding track provided on the mold base (1) under the action of pressure; Step 6: heat-treating the target part blank obtained in step 5 to obtain the target part; The material of the control mold is a mixture of Al2O3 and SiO2, wherein the mass ratio of Al2O3 to SiO2 is 3 to 5:

1.

2. The method for preparing complex thin-walled parts using dynamic multi-dimensional control technology according to claim 1, characterized in that: In step 1, When using the investment casting process to prepare the control mold, low-temperature solid phase sintering is required. The sintering temperature is: 1000℃~1050℃, and the sintering time is: 6h~8h.

3. The method for preparing complex thin-walled parts using dynamic multi-dimensional control technology according to claim 1, characterized in that: In step 3, the prefabricated sheath is a stainless steel sheath.

4. The method for preparing complex thin-walled parts using dynamic multi-dimensional control technology according to claim 1, characterized in that: In step 4, the vacuum degree is ≤1×10 -2 Under the condition of Pa, the alloy powder is loaded into a prefabricated sleeve with a controlled mold. During the powder loading process, the prefabricated sleeve needs to be vibrated with a vibration frequency of 70Hz to 90Hz and an amplitude of 0.5mm to 1mm.

5. The method for preparing complex thin-walled parts using dynamic multi-dimensional control technology according to claim 4, characterized in that: After vibration treatment, the density of the alloy powder in the prefabricated package is 65% to 75%.

6. The method for preparing complex thin-walled parts using dynamic multi-dimensional control technology according to claim 1, characterized in that: In step 4, the degassing temperature of the degassing and sealing treatment is: 500℃~600℃; after the degassing and sealing treatment, the entire prefabricated package is tested for airtightness, and the leakage rate is ≤1×10-10Pa·m 3 / s.

7. The method for preparing complex thin-walled parts using dynamic multi-dimensional control technology according to claim 1, characterized in that: In step 5, the temperature of the hot isostatic pressing treatment is: 900° C. to 950° C., the heat preservation and pressure holding time is: 2 h to 3 h, and the pressure is: 120 MPa to 140 MPa.

8. The method for preparing complex thin-walled parts using dynamic multi-dimensional control technology according to claim 1, characterized in that: The density of the target workpiece blank in step 5 is: 100%.

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