Quenching process for thin-walled superalloy lattice structures

Abstract

The present application belongs to the field of material processing technology, and relates to a quenching process of a high-temperature alloy thin-wall lattice structure, which comprises the following steps: placing the high-temperature alloy thin-wall lattice structure in a vacuum heat treatment furnace, performing heat treatment, and then cooling out of the furnace. When the heat treatment temperature is less than or equal to 950 DEG C, the furnace temperature is increased to the heat treatment temperature at a first temperature increasing rate of 1-30 DEG C / min, and is kept for 30-80 min; when the heat treatment temperature is greater than 950 DEG C, the furnace temperature is increased to 900-960 DEG C at the first temperature increasing rate of 1-30 DEG C / min, and is kept for 30-80 min; and then the furnace temperature is increased to the heat treatment temperature at a second temperature increasing rate of 0.5-5 DEG C / min, and is kept for 30-80 min. The high-temperature alloy thin-wall lattice structure is subjected to vacuum heat treatment at a certain temperature for a period of time, which is beneficial to eliminating printing stress and adjusting internal organizational structure.

Description

Technical Field

[0001] This invention belongs to the field of materials processing technology and relates to the quenching process of high-temperature alloy thin-walled lattice structure parts. Background Technology

[0002] Currently, the requirements for lightweight and high-performance aircraft and aero-engines are becoming increasingly stringent. Traditional spacecraft design needs to consider both structure and function; that is, it requires structural components with high load-bearing capacity on the one hand, and special requirements such as heat insulation and vibration reduction on the other. Therefore, the development of functional materials with excellent structural and functional properties has become an inevitable requirement. Lattice structures, with their high porosity, high specific surface area, and open-pore characteristics, have enormous potential for application in the aerospace field.

[0003] Thin-walled (skin) lattice structures include an outer thin-walled (skin) structure and an inner lattice structure filled within the outer thin-walled (skin) structure. Due to the large cross-sectional deformation at the contact points, the internal stress of 3D-printed thin-walled lattice structures is relatively large. Due to the structure, inappropriate heat treatment processes can amplify the influence of local stress, causing macroscopic cracks and leading to the scrapping of parts. Summary of the Invention

[0004] The purpose of this invention is to address the shortcomings of existing technologies by providing a quenching process for thin-walled lattice structures made of high-temperature alloys.

[0005] The objective of this invention is achieved through the following technical solution:

[0006] The quenching process of high-temperature alloy thin-walled lattice structure parts includes the following steps: placing the high-temperature alloy thin-walled lattice structure parts in a vacuum heat treatment furnace for heat treatment, and then cooling them out of the furnace.

[0007] Thin-walled lattice structural components feature a lattice structure (a network-like geometric structure consisting of a series of individual elements connected by joints) covered with a skin ≤2mm thick, which can significantly reduce weight while maintaining structural rigidity. The raw materials for manufacturing high-temperature alloy thin-walled lattice structural components include high-temperature alloys. High-temperature alloys refer to a class of alloys whose operating temperature range is typically between 600 and 1000℃, and can even reach 1200℃ under short-term operating conditions (within 100s). Nickel-based high-temperature alloys, such as GH4169, can be cited as examples.

[0008] Preferably, the heat treatment temperature is 800–1200°C.

[0009] More preferably, the heat treatment temperature is 900–1100°C.

[0010] Preferably, when the heat treatment temperature is ≤950℃, the heat treatment step includes: raising the furnace temperature to the heat treatment temperature at a heating rate of 1~30℃ / min and holding it at that temperature for 30~80min; when the heat treatment temperature is >950℃, the heat treatment step includes: raising the furnace temperature to 900~960℃ at a first heating rate of 1~30℃ / min and holding it at that temperature for 30~80min; and then raising the furnace temperature to the heat treatment temperature at a second heating rate of 0.5~5℃ / min and holding it at that temperature for 30~80min.

[0011] During heat treatment, a certain temperature is maintained for a period of time to reduce the asynchronous deformation caused by the different expansion rates of the lattice and thin wall when the thin-walled lattice structure expands under heat. This helps to eliminate printing stress and avoid cracks and local overheating during heat treatment of the thin-walled lattice structure, which would affect the microstructure properties of the alloy and facilitate the adjustment of the internal structure.

[0012] Preferably, during the heat treatment process, the first heating rate is 1–10 °C / min, and the second heating rate is 0.5–3 °C / min. Using a slow heating method during heat treatment helps to eliminate internal stress.

[0013] Preferably, during heat treatment, the second heating rate is lower than the first heating rate. The slower second heating rate helps reduce material deformation at high temperatures caused by excessive temperature gradients.

[0014] Preferably, the vacuum level inside the vacuum heat treatment furnace is controlled to be ≤5×10 during the heat treatment process. -3 Pa. A high-temperature alloy thin-walled lattice structure is placed in a vacuum heat treatment furnace, and a vacuum is drawn to ensure that the vacuum degree inside the furnace is ≤5×10⁻⁶. -3 Pa, the entire heat treatment is ≤5×10 -3 The procedure was carried out under a vacuum of Pa.

[0015] Preferably, the cooling includes the following steps: introducing inert gas, adjusting the pressure of the inert gas to 6-12 bar, and turning on the fan with an airflow of 2-8 m³ / h. 3 The food is removed from the oven when the temperature drops below 40°C.

[0016] To stabilize the microstructure formed at high temperatures, a gaseous medium must be introduced during cooling to create convection within the furnace, accelerating the cooling efficiency of the thin-walled lattice structure. To prevent oxidation of the structural components, an inert gas must be introduced. The inert gas pressure and fan airflow are key factors determining the cooling rate; the inert gas pressure should be controlled at 6–12 bar, and the fan airflow at 2–8 m³ / s. 3 / min, by using high gas pressure and forced air cooling to quickly remove heat.

[0017] Preferably, during the cooling process, the cooling rate is controlled to be ≥100℃ / min. Only when the cooling rate is ≥100℃ / min can the air quenching effect of the present invention be achieved.

[0018] Preferably, the high-temperature alloy thin-walled lattice structure is formed by metal 3D printing. The high-temperature alloy thin-walled lattice structure formed by metal 3D printing has relatively high internal stress, and the quenching process of this invention has a significant performance improvement effect.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. This invention performs vacuum heat treatment on high-temperature alloy thin-walled lattice structure parts formed by metal 3D printing. During this process, holding the part at a certain temperature for a period of time can reduce the asynchronous deformation caused by the different expansion rates of the lattice and thin wall when the thin-walled lattice structure parts are heated, which is beneficial to eliminate printing stress and adjust the internal structure.

[0021] 2. This invention controls the heating rate and holding time during the heat treatment process to better eliminate stress and regulate the microstructure, thereby improving the performance of structural components.

[0022] 3. In the cooling process, the present invention combines the introduction of inert gas to achieve a higher medium pressure with forced air cooling to achieve the purpose of quickly removing heat.

[0023] 4. The present invention controls the cooling rate during the cooling process, which can effectively solve the problem of unstable material properties after heat treatment. Attached Figure Description

[0024] Figure 1 This is a product drawing of a high-temperature alloy thin-walled lattice structure component in an embodiment of the present invention. Detailed Implementation

[0025] The technical solution of the present invention will be further described and illustrated below with reference to specific embodiments and accompanying drawings. It should be understood that the specific embodiments described herein are only for the purpose of helping to understand the present invention and are not intended to limit the specific scope of the present invention. Furthermore, the accompanying drawings used herein are merely for better illustrating the content disclosed in the present invention and do not limit the scope of protection. Unless otherwise specified, the raw materials used in the embodiments of the present invention are all commonly used in the art, and the methods used in the embodiments are all conventional methods in the art.

[0026] In the following embodiments, the high-temperature alloy thin-walled lattice structure used is a GH4169 nickel-based high-temperature alloy thin-walled lattice structure formed by metal 3D printing, with a wall thickness of approximately 1 mm, and its structure is as follows. Figure 1 As shown.

[0027] Example 1

[0028] The quenching process in this embodiment is carried out in a horizontal vacuum heat treatment furnace with an effective heating area of ​​800mm×800mm×1200mm. The high-temperature alloy thin-walled lattice structure is placed inside the vacuum heat treatment furnace, and the furnace is evacuated to a vacuum level of 1×10⁻⁶. -3 The furnace temperature was initially increased to 950°C at a rate of 10°C / min and held for 50 minutes. Then, it was increased to 1050°C at a rate of 1°C / min and held for 50 minutes. Cooling was then performed, specifically by introducing argon gas to a pressure of 10 bar and turning on the blower, controlling the airflow at 6 m³ / min. 3 The cooling rate is controlled at 200℃ / min until the temperature drops below 40℃ before being removed from the furnace.

[0029] Example 2

[0030] The quenching process in this embodiment is carried out in a horizontal vacuum heat treatment furnace with an effective heating area of ​​800mm×800mm×1200mm. The high-temperature alloy thin-walled lattice structure is placed inside the vacuum heat treatment furnace, and the furnace is evacuated to a vacuum level of 2×10⁻⁶. -3 The furnace temperature was initially increased to 900°C at a rate of 9°C / min and held for 40 minutes. Then, it was increased to 980°C at a rate of 2°C / min and held for 60 minutes. Cooling was then performed, specifically by introducing argon gas to a pressure of 9 bar and turning on the blower with an airflow of 4 m³ / min. 3 The cooling rate is controlled at 150℃ / min until the temperature drops below 40℃ before being removed from the furnace.

[0031] Example 3

[0032] The quenching process in this embodiment is carried out in a horizontal vacuum heat treatment furnace with an effective heating area of ​​800mm × 800mm × 1200mm. The high-temperature alloy thin-walled lattice structure is placed inside the vacuum heat treatment furnace, and the furnace is evacuated to a vacuum level of 0.5 × 10⁻⁶. -3 The furnace temperature was initially increased to 930°C at a rate of 5°C / min and held for 60 minutes. Then, it was increased to 1000°C at a rate of 0.5°C / min and held for 40 minutes. Cooling was then performed, specifically by introducing argon gas to a pressure of 11 bar and turning on the blower with an airflow of 8 m³ / min. 3 The cooling rate is controlled at 270℃ / min until the temperature drops below 40℃ before being removed from the furnace.

[0033] Example 4

[0034] The quenching process in this embodiment is carried out in a horizontal vacuum heat treatment furnace with an effective heating area of ​​800mm×800mm×1200mm. The high-temperature alloy thin-walled lattice structure is placed inside the vacuum heat treatment furnace, and the furnace is evacuated to a vacuum level of 1×10⁻⁶. -3 The furnace temperature was increased to 900°C at a rate of 10°C / min and held for 45 minutes. Cooling was then performed by introducing argon gas to a pressure of 10 bar and turning on the blower with an airflow of 4 m³ / min. 3 The cooling rate is controlled at 180℃ / min until the temperature drops below 40℃ before being removed from the furnace.

[0035] Comparative Example 1

[0036] The quenching process of Comparative Example 1 was carried out in a horizontal vacuum heat treatment furnace with an effective heating zone of 800mm × 800mm × 1200mm. The high-temperature alloy thin-walled lattice structure was placed inside the vacuum heat treatment furnace, and the furnace was evacuated to a vacuum level of 1 × 10⁻⁶. -3 Pa, then raise the furnace temperature to 1050°C at a heating rate of 10°C / min and hold for 50 minutes, then cool, the cooling process is the same as in Example 1.

[0037] Comparative Example 2

[0038] The quenching process of Comparative Example 2 was carried out in a horizontal vacuum heat treatment furnace with an effective heating zone of 800mm × 800mm × 1200mm. The high-temperature alloy thin-walled lattice structure was placed inside the vacuum heat treatment furnace, and the furnace was evacuated to a vacuum level of 1 × 10⁻⁶. -3 Pa, then raise the furnace temperature to 1050°C at a heating rate of 1°C / min and hold for 50 minutes, then cool, the cooling process is the same as in Example 1.

[0039] Comparative Example 3

[0040] The quenching process of Comparative Example 3 was carried out in a horizontal vacuum heat treatment furnace with an effective heating zone of 800mm × 800mm × 1200mm. The high-temperature alloy thin-walled lattice structure was placed inside the vacuum heat treatment furnace, and the furnace was evacuated to a vacuum level of 1 × 10⁻⁶. -3 Pa, then raise the furnace temperature to 950°C at a heating rate of 50°C / min and hold for 50 min, then raise the furnace temperature to 1050°C at a heating rate of 50°C / min and hold for 50 min, and then cool, the cooling process is the same as in Example 1.

[0041] Comparative Example 4

[0042] The quenching process of Comparative Example 4 was carried out in a horizontal vacuum heat treatment furnace with an effective heating zone of 800mm × 800mm × 1200mm. The high-temperature alloy thin-walled lattice structure was placed inside the vacuum heat treatment furnace, and the furnace was evacuated to a vacuum level of 1 × 10⁻⁶. -3 Pa, then raise the furnace temperature to 950°C at a heating rate of 1°C / min and hold for 50 min, then raise the furnace temperature to 1050°C at a heating rate of 1°C / min and hold for 50 min, and then cool, the cooling process is the same as in Example 1.

[0043] Comparative Example 5

[0044] The quenching process of Comparative Example 5 was carried out in a horizontal vacuum heat treatment furnace with an effective heating zone of 800mm × 800mm × 1200mm. The high-temperature alloy thin-walled lattice structure was placed inside the vacuum heat treatment furnace, and the furnace was evacuated to a vacuum level of 1 × 10⁻⁶. -3 Pa, then raise the furnace temperature to 950°C at a heating rate of 10°C / min and hold for 50 min, then raise the furnace temperature to 1050°C at a heating rate of 10°C / min and hold for 50 min, and then cool, the cooling process is the same as in Example 1.

[0045] Comparative Example 6

[0046] The quenching process of Comparative Example 6 was carried out in a horizontal vacuum heat treatment furnace with an effective heating zone of 800mm × 800mm × 1200mm. The high-temperature alloy thin-walled lattice structure was placed inside the vacuum heat treatment furnace, and the furnace was evacuated to a vacuum level of 1 × 10⁻⁶. -3 Pa, then raise the furnace temperature to 950°C at a heating rate of 1°C / min and hold for 50 min, then raise the furnace temperature to 1050°C at a heating rate of 10°C / min and hold for 50 min, and then cool, the cooling process is the same as in Example 1.

[0047] Comparative Example 7

[0048] The quenching process of Comparative Example 6 was carried out in a horizontal vacuum heat treatment furnace with an effective heating zone of 800mm × 800mm × 1200mm. The high-temperature alloy thin-walled lattice structure was placed inside the vacuum heat treatment furnace, and the furnace was evacuated to a vacuum level of 1 × 10⁻⁶. -3 Pa, then raise the furnace temperature to 950°C at a heating rate of 2°C / min and hold for 50 min, then raise the furnace temperature to 1050°C at a heating rate of 8°C / min and hold for 50 min, and then cool, the cooling process is the same as in Example 1.

[0049] Comparative Example 8

[0050] The difference between Comparative Example 8 and Example 1 is that the cooling process of Comparative Example 8 is as follows: argon gas is introduced to a pressure of 3 bar, and the fan is turned on with an airflow controlled at 2 m³ / s. 3 The cooling rate is controlled at 50°C / min until the temperature drops below 40°C before being removed from the furnace. Everything else is the same as in Example 1.

[0051] Comparative Example 9

[0052] The difference between Comparative Example 9 and Example 1 is that the cooling process in Comparative Example 8 is as follows: the fan is turned on and the airflow is controlled at 8m³ / s. 3 The cooling rate is controlled at 60°C / min until the temperature drops below 40°C before being removed from the furnace. Everything else is the same as in Example 1.

[0053] The performance of the high-temperature alloy thin-walled lattice structure parts of Examples 1-4 and Comparative Examples 1-9 after quenching was tested, and the results are shown in Table 1.

[0054] Table 1. Performance results of structural components in Examples 1-4 and Comparative Examples 1-9

[0055]

[0056]

[0057] As can be seen from Table 1: Comparative Examples 1 and 2 did not undergo stage heat preservation during the heat treatment process, resulting in higher internal stress in the structural components of Comparative Examples 1 and 2, which reduced the performance of the structural components; Comparative Examples 3 to 7 used inappropriate heating rates during the heat treatment process, which also reduced the performance of the structural components; Comparative Example 8 had a slow cooling rate during the cooling process, which affected the quenching effect; Comparative Example 9 did not introduce gas and directly used air cooling, which had a limited air cooling rate, thus also affecting the quenching effect.

[0058] All aspects, embodiments, and features of this invention should be considered illustrative in all respects and not limiting of the invention; the scope of the invention is defined only by the claims. Other embodiments, modifications, and uses will become apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0059] In the preparation method of this invention, the order of the steps is not limited to the listed order. For those skilled in the art, variations in the order of the steps without creative effort are also within the scope of protection of this invention. Furthermore, two or more steps or actions can be performed simultaneously.

[0060] Finally, it should be noted that the specific embodiments described herein are merely illustrative examples of the invention and are not intended to limit the implementation of the invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them; it is neither necessary nor possible to exemplify all embodiments here. However, these obvious variations or modifications derived from the essential spirit of the invention still fall within the scope of protection of the invention, and interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A quenching process for thin-walled lattice structure components of high-temperature alloys, characterized in that, The thin-walled lattice structure has a lattice structure covered by a skin with a thickness of ≤2mm. It is formed by metal 3D printing. The quenching process includes the following steps: placing the high-temperature alloy thin-walled lattice structure in a vacuum heat treatment furnace for heat treatment, and then cooling it out of the furnace. The heat treatment steps include: raising the furnace temperature to 900-960℃ at a first heating rate of 1-10℃ / min and holding it at that temperature for 30-80min; then raising the furnace temperature to the heat treatment temperature of 980-1100℃ at a second heating rate of 0.5-3℃ / min and holding it at that temperature for 30-80min, wherein the second heating rate is less than the first heating rate. The cooling process includes the following steps: introducing inert gas and adjusting the pressure of the inert gas to 6-12 bar; turning on the fan and setting the airflow to 2-8 m³ / h. 3 The cooling rate is controlled at ≥100℃ / min, and the product is removed from the furnace only when the temperature drops below 40℃.

2. The quenching process according to claim 1, characterized in that, During the heat treatment process, the vacuum level inside the vacuum heat treatment furnace should be controlled to be ≤5×10. -3 Pa.

Images