Hot isostatic pressing ceramic die high-temperature alloy part forming method

Abstract

The invention provides a hot isostatic pressing ceramic die high-temperature alloy part forming method, and belongs to the technical field of hot isostatic pressing forming. The problems that in an existing powder hot isostatic pressing forming technology, the manufacturing cost of a metal mold is large, the sheath removing difficulty is large, and sharp corners and other areas are difficult to form are solved. The method comprises the following steps: step 1, preparing a wax mold; step 2, preparing ceramic slurry; step 3, coating the ceramic slurry; 4, dewaxing and ceramic mold firing are carried out; 5, filling the ceramic mold; step 6, sheath filling; step 7, carrying out vacuum degassing; step 8, hot isostatic pressing; and step 9, removing the sheath. The method is mainly used for forming the hot isostatic pressing ceramic die high-temperature alloy part.

Description

Technical Field

[0001] The invention belongs to the technical field of hot isostatic pressing, and in particular relates to a hot isostatic pressing ceramic die high temperature alloy part forming method. Background Art

[0002] Powder hot isostatic pressing technology provides a new forming method for alloy parts with high performance requirements and complex shapes, but the design and manufacture of the sleeve is the key to powder hot isostatic pressing technology. Currently, the sleeve is made of soft steel that is easy to deform and easy to remove. The production cost of the metal mold is high, the sleeve is difficult to remove, and the sharp corners are difficult to form. Summary of the invention

[0003] In view of this, the present invention aims to propose a hot isostatic pressing ceramic mold high-temperature alloy part forming method to solve the problems existing in the existing powder hot isostatic pressing forming technology, such as high production cost of metal molds, difficulty in removing the jacket, and difficulty in forming areas such as sharp corners.

[0004] To achieve the above object, the present invention adopts the following technical solution: a hot isostatic pressing ceramic mold high temperature alloy forming method, which comprises the following steps:

[0005] Step 1: Preparation of wax model: Print the wax model according to the size of the provided digital model;

[0006] Step 2: Preparation of ceramic slurry: Add ceramic powder into polyvinyl alcohol solution and stir evenly until there are no particles;

[0007] Step 3: Ceramic slurry coating: coating the ceramic slurry on the wax model, and taking a natural shade drying method to make a ceramic mold blank on the wax model;

[0008] Step 4: Dewaxing and firing the ceramic mold: After the ceramic mold is dried, the ceramic mold is placed in a baking furnace for dewaxing and firing at the same time;

[0009] Step 5: Ceramic mold filling: Fill the alloy powder into the ceramic mold, and seal the port of the ceramic mold after compaction;

[0010] Step 6: Filling the metal sleeve: put some Al2O3 coarse powder into the metal sleeve, put the ceramic mold into the metal sleeve and fix it in the Al2O3 coarse powder, then fill the space between the metal sleeve and the ceramic mold with Al2O3 coarse powder, weld the upper cover and the exhaust pipe, fill the remaining space with Al2O3 coarse powder through the exhaust nozzle and the exhaust pipe, and vibrate and fill it to 2 / 3 of the exhaust pipe;

[0011] Step 7: Vacuum degassing: first degas at room temperature, then degas at high temperature. After the high temperature degassing is completed, cut off the exhaust pipe and immediately seal the break with argon arc welding;

[0012] Step 8: Hot isostatic pressing: put the package into the hot isostatic pressing furnace for hot isostatic pressing treatment, adopt the hot isostatic pressing process of heating first and then pressurizing, the initial pressure is 10MPa, gradually increase the temperature, when the temperature rises to 1050℃, keep the pressure for 1h in this state, after low-pressure preheating and forming, reduce the furnace temperature to below 200℃, fill in protective gas, make the pressure reach about 60MPa, increase the temperature and pressure at the same time, increase the furnace temperature to 1200℃ at a heating rate of 5℃ / min, at this time the pressure in the furnace reaches 130MPa, keep the temperature and pressure for 2h, then reduce the temperature and release the pressure, and take out the package after the furnace cools down;

[0013] Step 9: Remove the sheath: After hot isostatic pressing, remove the outer metal sheath by machining, and the inner ceramic part can be knocked and broken to take out the formed alloy part.

[0014] Furthermore, in step 1, the wax model is printed using laser sintering technology.

[0015] Furthermore, the stirring method in step 2 is electromagnetic stirring.

[0016] Furthermore, the powder-liquid ratio of the ceramic powder to the polyvinyl alcohol solution in step 2 is 1.2:1.

[0017] Furthermore, the components of the ceramic powder in step 2 are Al2O3, SiO2, MgO and TiO2.

[0018] Furthermore, the percentages of the components in the ceramic powder are Al2O3: 10%-30%, SiO2: 60%-85%, MgO: 2%-6% and TiO2: 0.5%-3.5%.

[0019] Furthermore, the calcination furnace temperature in step 4 is 950° C. and is kept warm for 2 hours.

[0020] Furthermore, in step 5, a stainless steel mesh is used to seal the port of the ceramic mold.

[0021] Furthermore, after degassing at room temperature for 2 hours in step 7, the temperature is raised to 100°C for high-temperature degassing, and degassing is performed for 1 hour every time the temperature is raised by 100°C, until degassing is performed for 2 hours when the temperature is raised to 600°C, and the high-temperature degassing is completed.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention provides a method for forming high-temperature alloy parts by hot isostatic pressing ceramic molds. A ceramic mold is used instead of a metal mold to solve the problems of high manufacturing cost of metal molds, difficulty in removing the jacket, and difficulty in forming areas such as sharp corners. The ceramic mold can be used to make parts with extremely complex shapes, has good adaptability, low cost, low pressing temperature, high material utilization rate, and easy demolding, thereby achieving cost reduction and efficiency improvement.

[0024] 2. The ceramic mold of the present invention is dewaxed and fired simultaneously in a roasting furnace. In this way, dewaxing and firing are performed simultaneously, which improves efficiency and reduces processing procedures, furnace opening and labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0026] Figure 1 It is a process flow chart of a hot isostatic pressing ceramic mold high temperature alloy part forming method according to the present invention;

[0027] Figure 2 It is a vacuum degassing process curve in a hot isostatic pressing ceramic mold high temperature alloy part forming method described in the present invention;

[0028] Figure 3 The hot isostatic pressing process curve in the hot isostatic pressing ceramic mold high-temperature alloy part forming method described in the present invention. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely explain the technical solutions in the embodiments of the present invention. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0030] See also Figure 1-3 The present embodiment is described as a method for forming a high temperature alloy part by hot isostatic pressing of a ceramic mold, which comprises the following steps:

[0031] Step 1: Preparation of wax model: Print the wax model according to the size of the provided digital model to ensure the size and surface quality of the wax model. The early test uses a pressed wax model, which has low cost, convenient processing and high efficiency;

[0032] Step 2: Preparation of ceramic slurry: Add ceramic powder into polyvinyl alcohol solution and stir evenly until there are no particles;

[0033] Step 3: Ceramic slurry coating: coating the ceramic slurry on the wax model, and taking a natural shade drying method to make a ceramic mold blank on the wax model;

[0034] Step 4: Dewaxing and firing of ceramic mold: After the ceramic mold is dried, it is placed in a baking furnace at a furnace temperature of 950°C for 2 hours to allow dewaxing and firing to proceed simultaneously. This method of dewaxing and firing simultaneously improves efficiency, reduces processing procedures, furnace opening and labor costs;

[0035] Step 5: Ceramic mold filling: Fill the alloy powder into the ceramic mold, and seal the port of the ceramic mold with a stainless steel mesh after compaction;

[0036] Step 6: Filling the metal sleeve: put a small amount of Al2O3 coarse powder into the metal sleeve, put the ceramic mold into the metal sleeve and fix it in the Al2O3 coarse powder, then fill the space between the metal sleeve and the ceramic mold with Al2O3 coarse powder, the Al2O3 coarse powder serves as the pressure transmission medium between the metal sleeve and the ceramic mold, and weld the upper cover and the exhaust pipe, fill the remaining space with Al2O3 coarse powder through the exhaust nozzle and the exhaust pipe, and vibrate and fill it to 2 / 3 of the exhaust pipe;

[0037] Step 7: Vacuum degassing: first degas at room temperature, then degas at high temperature. After the high temperature degassing is completed, the exhaust pipe is cut off and the port is immediately sealed with argon arc welding. In this embodiment, the room temperature degassing is carried out for 2 hours, and then the temperature is raised to 100°C for high temperature degassing, and degassing is carried out for 1 hour every time the temperature is raised by 100°C, until the temperature is raised to 600°C for 2 hours. After the high temperature degassing is completed, the exhaust pipe is cut off and the port is immediately sealed with argon arc welding to package the package. At this time, the vacuum degree in the package reaches 1×10 -3 Pa, vacuum degassing process curve is as follows Figure 2 As shown, the vacuum degassing packaging process used in this embodiment is suitable for hot isostatic pressing of high-temperature alloy parts and can meet the vacuum requirements of ceramic molds;

[0038] Step 8: hot isostatic pressing: the package is placed in a hot isostatic pressing furnace for hot isostatic pressing treatment, and a hot isostatic pressing process of heating first and then pressurizing is adopted. The initial pressure is 10MPa, and the temperature is gradually and slowly increased at a heating rate of 5°C / min. When the temperature rises to 1050°C, the pressure is maintained for 1h in this state. After low-pressure preheating and forming, the furnace temperature is reduced to below 200°C, and protective gas is filled to make the pressure reach about 60MPa. At the same time, the temperature and pressure are increased, and the furnace temperature is increased to 1200°C at a heating rate of 5°C / min. At this time, the pressure in the furnace reaches 130MPa. In this embodiment, the furnace temperature is increased to 1200±10°C, and the pressure is not less than 130MPa. The temperature and pressure are maintained for 2h, and then the temperature is reduced and the pressure is released. After the furnace is cooled, the package is taken out. During the hot isostatic pressing process, the external metal package will be subjected to gas pressure, and then the pressure is transmitted to the ceramic mold through the pressure transmission medium to obtain an alloy component of corresponding size;

[0039] Step 9: Remove the sheath: After hot isostatic pressing, the outer metal sheath is removed by machining, and the internal ceramic part can be knocked and broken to take out the formed alloy part. Since the ceramic material is sintering-resistant, the temperature at which the ceramic particles are completely sintered is not reached during hot isostatic pressing at 1200℃. After the hot isostatic pressing process, the ceramic particles are in a semi-sintered state and can be knocked and broken with a tool to take out the metal component.

[0040] In step 1 of this embodiment, the wax model is printed using laser sintering technology.

[0041] The stirring method in step 2 of this embodiment is electromagnetic stirring.

[0042] In the step 2 of this embodiment, the powder-to-liquid ratio of the ceramic powder to the polyvinyl alcohol solution is 1.2:1.

[0043] The components of the ceramic powder in step 2 of this embodiment are Al2O3, SiO2, MgO and TiO2.

[0044] The percentages of the components in the ceramic powder in this embodiment are Al2O3: 10%-30%, SiO2: 60%-85%, MgO: 2%-6% and TiO2: 0.5%-3.5%.

[0045] This embodiment uses a ceramic mold instead of a metal mold to solve the problems of high manufacturing cost of metal molds, difficulty in removing the sheath, and difficulty in forming areas such as sharp corners. The ceramic mold can be used to make parts with extremely complex shapes, has good adaptability, low cost, low pressing temperature, high material utilization rate, and easy demolding, thereby reducing costs and increasing efficiency.

[0046] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. A method for forming a high temperature alloy part by hot isostatic pressing of ceramic molds, characterized in that: It includes the following steps: Step 1: Preparation of wax model: Print the wax model according to the size of the provided digital model; Step 2: Preparation of ceramic slurry: Add ceramic powder into polyvinyl alcohol solution and stir evenly until there are no particles; Step 3: Ceramic slurry coating: coating the ceramic slurry on the wax model, and taking a natural shade drying method to make a ceramic mold blank on the wax model; Step 4: Dewaxing and firing the ceramic mold: After the ceramic mold is dried, the ceramic mold is placed in a baking furnace for dewaxing and firing at the same time; Step 5: Ceramic mold filling: Fill the alloy powder into the ceramic mold, and seal the port of the ceramic mold with a stainless steel mesh after compaction; Step 6: Filling the metal sleeve: put some Al2O3 coarse powder into the metal sleeve, put the ceramic mold into the metal sleeve and fix it in the Al2O3 coarse powder, then fill the space between the metal sleeve and the ceramic mold with Al2O3 coarse powder, weld the upper cover and the exhaust pipe, fill the remaining space with Al2O3 coarse powder through the exhaust nozzle and the exhaust pipe, and vibrate and fill it to 2 / 3 of the exhaust pipe; Step 7: Vacuum degassing: first degas at room temperature, then degas at high temperature. After the high temperature degassing is completed, cut off the exhaust pipe and immediately seal the break with argon arc welding; Step 8: Hot isostatic pressing: put the package into the hot isostatic pressing furnace for hot isostatic pressing treatment, adopt the hot isostatic pressing process of heating first and then pressurizing, the initial pressure is 10MPa, gradually increase the temperature, when the temperature rises to 1050℃, keep the pressure for 1h in this state, after low-pressure preheating and forming, reduce the furnace temperature to below 200℃, fill in protective gas, make the pressure reach about 60MPa, increase the temperature and pressure at the same time, increase the furnace temperature to 1200℃ at a heating rate of 5℃ / min, at this time the pressure in the furnace reaches 130MPa, keep the temperature and pressure for 2h, then reduce the temperature and release the pressure, and take out the package after the furnace cools down; Step 9: Remove the sheath: After hot isostatic pressing, remove the outer metal sheath by machining, and the inner ceramic part can be knocked and broken to take out the formed alloy part.

2. A hot isostatic pressing ceramic mold high temperature alloy forming method according to claim 1, characterized in that: In the step 1, the wax model is printed using laser sintering technology.

3. The method for forming a high temperature alloy part by hot isostatic pressing of ceramic mold according to claim 1, characterized in that: The stirring method in step 2 is electromagnetic stirring.

4. The method for forming a high temperature alloy part by hot isostatic pressing of ceramic mold according to claim 1, characterized in that: The powder-to-liquid ratio of the ceramic powder to the polyvinyl alcohol solution in step 2 is 1.2:

1.

5. The method for forming a high temperature alloy part by hot isostatic pressing of ceramic mold according to claim 1, characterized in that: The components of the ceramic powder in step 2 are Al2O3, SiO2, MgO and TiO2.

6. The method for forming a high temperature alloy part by hot isostatic pressing of ceramic mold according to claim 3, characterized in that: The percentages of the components in the ceramic powder are Al2O3: 10%-30%, SiO2: 60%-85%, MgO: 2%-6% and TiO2: 0.5%-3.5%.

7. The method for forming a high temperature alloy part by hot isostatic pressing of ceramic mold according to claim 1, characterized in that: The temperature of the calcining furnace in step 4 is 950° C. and is kept at this temperature for 2 hours.

8. The method for forming a high temperature alloy part by hot isostatic pressing of ceramic mold according to claim 1, characterized in that: In step 5, a stainless steel mesh is used to seal the port of the ceramic mold.

9. The method for forming a high temperature alloy part by hot isostatic pressing of ceramic mold according to claim 1, characterized in that: In step 7, after degassing at room temperature for 2 hours, the temperature is raised to 100° C. for high-temperature degassing, and degassing is performed for 1 hour every time the temperature is raised by 100° C., until degassing is performed for 2 hours at 600° C., and the high-temperature degassing is completed.

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