Heat treatment method for high-chromium nickel-based superalloy 3D printed structural parts

Abstract

The present application relates to a kind of high chromium nickel-based superalloy 3D printing structural member heat treatment method.The above-mentioned heat treatment method includes the following steps: high chromium nickel-based superalloy 3D printing structural member is placed into heat treatment furnace;Vacuumizing treatment is carried out to heat treatment furnace;High chromium nickel-based superalloy 3D printing structural member in vacuum environment is heated for the first time, until heated to 600 ℃±10 ℃;High chromium nickel-based superalloy 3D printing structural member is kept for the first preset time period;High chromium nickel-based superalloy 3D printing structural member in vacuum environment is heated for the second time, until heated to 800 ℃±10 ℃;High chromium nickel-based superalloy 3D printing structural member is kept for the second preset time period;High chromium nickel-based superalloy 3D printing structural member is cooled to room temperature.The use of heat treatment method can improve the processing efficiency of high chromium nickel-based superalloy 3D printing structural member, reduce processing cost, improve high temperature endurance performance, so that tensile property, elongation and impact performance are all beyond the level of forging.

Description

Technical Field

[0001] This invention relates to the field of 3D printing technology, and in particular to a heat treatment method for 3D printed structural parts made of high-chromium nickel-based high-temperature alloys. Background Technology

[0002] Laser selective melting (LSM) additive manufacturing technology is currently one of the preferred processes for fabricating complex hot-end components of aero-engines. However, the rapid solidification characteristic of this technology under non-equilibrium conditions results in a unique microstructure, making it difficult to meet performance requirements using standard heat treatment regimes for traditional casting high-temperature alloys. Taking K4648 high-Cr nickel-based high-temperature alloy as an example, the standard heat treatment regime for K4648 alloy is solution treatment followed by aging (1180℃×4h + 900℃×16h). 3D-printed parts treated with this regime exhibit a large precipitation of brittle α-Cr phases at grain boundaries, leading to a sharp decline in high-temperature creep resistance, far below the casting standard (only reaching 50% of the casting standard). Developing a reasonable heat treatment regime that maintains the other basic mechanical properties of 3D-printed K4648 alloy while suppressing α-Cr precipitation to significantly improve creep resistance is a significant challenge. Summary of the Invention

[0003] Therefore, it is necessary to provide a heat treatment method for high-chromium nickel-based superalloy 3D printed structural parts that can maintain the basic mechanical properties of the parts while suppressing α-Cr precipitation.

[0004] A heat treatment method for 3D-printed structural parts made of high-chromium nickel-based superalloy includes the following steps:

[0005] The high-chromium nickel-based high-temperature alloy 3D printed structural parts are placed in a heat treatment furnace; the material of the high-chromium nickel-based high-temperature alloy 3D printed structural parts is a high-chromium nickel-based high-temperature alloy, and the mass percentage content of chromium in the high-chromium nickel-based high-temperature alloy is ≥32%.

[0006] The heat treatment furnace is evacuated to ensure that the high-chromium nickel-based high-temperature alloy 3D printed structural parts are in a vacuum environment.

[0007] The high-chromium nickel-based high-temperature alloy 3D printed structural part is heated for the first time in a vacuum environment until the surface temperature of the high-chromium nickel-based high-temperature alloy 3D printed structural part rises to 600℃±10℃.

[0008] The high-chromium nickel-based high-temperature alloy 3D printed structural component is kept warm for a first preset time period after the first heating.

[0009] The high-chromium nickel-based high-temperature alloy 3D printed structural part in a vacuum environment is heated a second time until the surface temperature of the high-chromium nickel-based high-temperature alloy 3D printed structural part rises to 800℃±10℃.

[0010] The high-chromium nickel-based high-temperature alloy 3D printed structural component is kept warm for a second preset time period after the second heating.

[0011] The high-chromium nickel-based high-temperature alloy 3D printed structural part was cooled to room temperature.

[0012] In one embodiment, the high-chromium nickel-based superalloy comprises the following components in weight percentage: Cr ≥ 32%, W: 4.3-5.5%, Mo: 2.3-3.5%, Al: 0.7-1.3%, Ti: 0.7-1.3%, Nb: 0.7-1.3%, C: 0.03-0.1%, Fe ≤ 0.5%, B ≤ 0.008%, Ce ≤ 0.03%, Si ≤ 0.3%, S ≤ 0.01%, Y ≤ 0.04%, Ca ≤ 0.02%, and Ni balance.

[0013] In one embodiment, the step of evacuating the heat treatment furnace involves: evacuating the heat treatment furnace until the pressure inside the furnace is less than or equal to 6.7 × 10⁻⁶. -3 Pa.

[0014] In one embodiment, the heating rate during the first heating and the second heating is 5-10°C / min.

[0015] In one embodiment, the heating rate during both the first and second heating is 5°C / min.

[0016] In one embodiment, the first preset time period and the second preset time period are the same, both being 2h±15min.

[0017] In one embodiment, the step of naturally cooling the high-chromium nickel-based superalloy 3D-printed structural part to room temperature includes the following steps:

[0018] The high-chromium nickel-based high-temperature alloy 3D printed structural part was cooled to a preset temperature in a vacuum environment;

[0019] Open the furnace door to air cool the high-chromium nickel-based high-temperature alloy 3D printed structure inside the heat treatment until the surface temperature of the high-chromium nickel-based high-temperature alloy 3D printed structure drops to room temperature.

[0020] The high-chromium nickel-based superalloy 3D-printed structural component, which has reached room temperature, is now ready for production.

[0021] In one embodiment, the preset temperature is less than 100°C.

[0022] In one embodiment, the heat treatment furnace is a molybdenum heating screen.

[0023] The heat treatment method described above for high-chromium nickel-based superalloy 3D-printed structural parts reduces the heat treatment time by 80% and lowers the temperature by more than 30% compared to standard solution aging heat treatment, effectively saving heat treatment time and costs. Furthermore, even if the chromium content in the high-chromium nickel-based superalloy 3D-printed structural parts is ≥32%, the heat treatment method described above significantly reduces the α-Cr precipitation, resulting in high-temperature creep rupture performance exceeding casting standards (≥40h) and room-temperature mechanical properties reaching the technical standards of similar castings and forgings. Therefore, the heat treatment method described above for high-chromium nickel-based superalloy 3D-printed structural parts effectively improves processing efficiency, reduces processing costs, and enhances high-temperature creep rupture performance. It also allows tensile properties, elongation, and impact properties to surpass forging levels without significantly reducing other mechanical properties. Attached Figure Description

[0024] Various other advantages and benefits will become apparent to those skilled in the art upon reading the detailed description of the preferred embodiments below. The accompanying drawings are for illustrative purposes only and are not intended to limit the scope of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0025] Figure 1 This is a schematic flowchart of the heat treatment method for a high-chromium nickel-based high-temperature alloy 3D printed structural part in a preferred embodiment of the present invention.

[0026] Figure 2 This is a schematic diagram of α-Cr precipitation in a high-chromium nickel-based superalloy 3D-printed structural part after heat treatment using a standard solution aging heat treatment process in the prior art of this invention.

[0027] Figure 3 This is a schematic diagram showing the precipitation of α-Cr in a 3D-printed high-chromium nickel-based superalloy structural part after heat treatment using the heat treatment method in this embodiment of the invention.

[0028] Figure 4 for Figure 1 The flowchart of step S700 in the heat treatment method of the high-chromium nickel-based high-temperature alloy 3D printed structural part is shown. Detailed Implementation

[0029] To facilitate understanding of the present invention, a more complete description will be given below with reference to the accompanying drawings. Preferred embodiments of the invention are shown in the drawings. However, the invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the invention.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] When describing positional relationships, unless otherwise specified, when an element is referred to as being "on" another element, it may be directly on the other element or there may be intermediate elements. It is also understood that when an element is referred to as being "between" two elements, it may be the only one between the two elements, or there may be one or more intermediate elements.

[0032] When using the terms “including,” “having,” and “comprising” as described herein, another component may be added unless explicitly qualifying terms such as “only,” “consisting of,” etc. are used. Unless otherwise stated, singular terms may include plural forms and should not be construed as having a quantity of one.

[0033] Traditional standard heat treatment for cast superalloys involves solution treatment followed by aging. However, this standard process leads to the precipitation of a large amount of brittle α-Cr phase at grain boundaries in 3D-printed parts, resulting in a sharp decline in their high-temperature creep resistance, falling far below the casting standard (only reaching 50% of the casting standard). To address this, the applicant proposes a heat treatment method for high-chromium nickel-based superalloy 3D-printed structural parts that maintains the other fundamental mechanical properties of the 3D-printed parts while simultaneously suppressing α-Cr precipitation to significantly improve creep resistance.

[0034] Please see Figure 1 The heat treatment method for high-chromium nickel-based high-temperature alloy 3D printed structural parts in a preferred embodiment of the present invention includes steps S100 to S700.

[0035] Step S100: Place the high-chromium nickel-based high-temperature alloy 3D printed structural part into a heat treatment furnace.

[0036] The heat treatment furnace can be a molybdenum heating screen, a vacuum heat treatment furnace, etc. Specifically, in this embodiment, the heat treatment furnace is a molybdenum heating screen.

[0037] High-chromium nickel-based superalloy powder was prepared using plasma rotary atomization powder preparation technology, and then high-chromium nickel-based superalloy 3D printed structural parts were obtained by laser selective melting process using the high-chromium nickel-based superalloy powder.

[0038] Among them, the material of the high-chromium nickel-based superalloy 3D printed structural parts is a high-chromium nickel-based superalloy, and the mass percentage content of chromium in the high-chromium nickel-based superalloy is ≥32%.

[0039] Specifically, the material of the high-chromium nickel-based superalloy 3D printed structural parts is a high-chromium nickel-based superalloy, which includes the following components by mass percentage: Cr ≥ 32%, W: 4.3-5.5%, Mo: 2.3-3.5%, Al: 0.7-1.3%, Ti: 0.7-1.3%, Nb: 0.7-1.3%, C: 0.03-0.1%, Fe ≤ 0.5%, B ≤ 0.008%, Ce ≤ 0.03%, Si ≤ 0.3%, S ≤ 0.01%, Y ≤ 0.04%, Ca ≤ 0.02%, and Ni as the balance.

[0040] Step S200: Vacuum treatment is performed inside the heat treatment furnace to place the high-chromium nickel-based high-temperature alloy 3D printed structural parts in a vacuum environment.

[0041] Specifically, the heat treatment chamber is evacuated until the pressure inside the furnace is less than or equal to 6.7 × 10⁻⁶. -3 Pa. This provides a vacuum environment for the subsequent heat treatment of high-chromium nickel-based superalloy 3D-printed structural parts, reducing the influence of oxygen and other substances in the air on the heat treatment process.

[0042] Step S300: The high-chromium nickel-based high-temperature alloy 3D printed structure is heated for the first time in a vacuum environment until the surface temperature of the high-chromium nickel-based high-temperature alloy 3D printed structure rises to 600℃±10℃.

[0043] Specifically, the high-chromium nickel-based high-temperature alloy 3D printed structural parts are heated for the first time in a vacuum environment, so that the surface temperature of the high-chromium nickel-based high-temperature alloy 3D printed structural parts is increased to 600℃±10℃ at a rate of 5-10℃ / min.

[0044] More specifically, the high-chromium nickel-based high-temperature alloy 3D printed structural parts were heated for the first time in a vacuum environment, so that the surface temperature of the high-chromium nickel-based high-temperature alloy 3D printed structural parts was increased to 600℃±10℃ at a rate of 5℃ / min.

[0045] Step S400: Keep the high-chromium nickel-based high-temperature alloy 3D printed structural part heated for a first preset time period.

[0046] Specifically, the high-chromium nickel-based high-temperature alloy 3D printed structural parts were kept at a temperature of 2 hours ± 15 minutes after the first heating.

[0047] Step S500: The high-chromium nickel-based high-temperature alloy 3D printed structure is heated a second time in a vacuum environment until the surface temperature of the high-chromium nickel-based high-temperature alloy 3D printed structure rises to 800℃±10℃.

[0048] Specifically, the high-chromium nickel-based high-temperature alloy 3D printed structural parts are heated a second time in a vacuum environment until the surface temperature of the high-chromium nickel-based high-temperature alloy 3D printed structural parts rises to 800℃±10℃ at a rate of 5-10℃ / min.

[0049] More specifically, the high-chromium nickel-based high-temperature alloy 3D printed structure is heated a second time in a vacuum environment until the surface temperature of the high-chromium nickel-based high-temperature alloy 3D printed structure rises to 800℃±10℃ at a rate of 5℃ / min.

[0050] Step S600: Keep the high-chromium nickel-based high-temperature alloy 3D printed structural part heated for the second time for a second preset period of time.

[0051] Specifically, the high-chromium nickel-based high-temperature alloy 3D printed structural parts were kept at a temperature of 2 hours ± 15 minutes after the second heating.

[0052] Thus, the first preset time period and the second preset time period are the same. Of course, in other embodiments, the first preset time period and the second preset time period may be different, but the difference in duration between the two should not be too large.

[0053] Step S700: Cool the high-chromium nickel-based high-temperature alloy 3D printed structural part to room temperature.

[0054] By executing steps S100 to S700, heat treatment of 3D-printed high-chromium nickel-based superalloy structural parts can be achieved. Steps S300 to S600 enable graded heating and holding of the 3D-printed high-chromium nickel-based superalloy structural parts. The target temperatures for the first and second heating stages are 600℃ and 800℃, respectively, with each holding period lasting 2 hours. Compared to the traditional standard solution aging process, the heat treatment time of this invention can be shortened by more than 80%, and the temperature reduced by more than 30%, effectively saving heat treatment time and costs.

[0055] Therefore, the heat treatment method described above for high-chromium nickel-based superalloy 3D-printed structural parts is designed for those with a chromium content ≥32%. However, the chromium content in these parts is very high, and before treatment, a large amount of brittle α-Cr phase precipitates at the grain boundaries, causing a sharp decline in the high-temperature creep resistance, far below the casting standard (only reaching 50% of the casting standard). The aforementioned heat treatment method can solve the problem of excessive α-Cr precipitation in high-chromium nickel-based superalloy 3D-printed structural parts with a chromium content ≥32%. Figure 2 and Figure 3 As shown in the figure, the white part is α-Cr. It can be clearly seen that compared with the traditional standard solution aging process, the heat treatment method of the present invention can significantly reduce the precipitation of α-Cr, thereby enabling the high-temperature creep performance of the high-chromium nickel-based high-temperature alloy 3D printed structural parts to exceed the casting standard (≥40h), and the room temperature mechanical properties to reach the technical standards of similar castings and forgings.

[0056] Furthermore, to more intuitively understand the advantages of the heat treatment methods used for the 3D printed high-chromium nickel-based superalloy structural parts, the mechanical properties of the 3D printed high-chromium nickel-based superalloy structural parts after heat treatment using different processes are statistically analyzed and compared below:

[0057]

[0058] Therefore, the use of the above-mentioned heat treatment method for high-chromium nickel-based superalloy 3D printed structural parts can effectively improve the processing efficiency of high-chromium nickel-based superalloy 3D printed structural parts, reduce processing costs, and improve high-temperature creep performance. Under the premise of not causing a significant decrease in other mechanical properties, the tensile properties, elongation and impact properties can all exceed the level of forgings.

[0059] Please refer to the following: Figure 4 In some embodiments, step S700 includes steps S701 to S703.

[0060] Step S701: Cool the high-chromium nickel-based high-temperature alloy 3D printed structural part to a preset temperature in a vacuum environment.

[0061] Specifically, the high-chromium nickel-based superalloy 3D-printed structural parts are naturally cooled in a vacuum environment until the surface temperature of the high-chromium nickel-based superalloy 3D-printed structural parts in the heat treatment furnace drops to a preset temperature. That is, the cooling of the high-chromium nickel-based superalloy 3D-printed structural parts enclosed in the heat treatment furnace is achieved by relying on the natural heat dissipation of the heat treatment furnace.

[0062] Step S702: Open the furnace door to air cool the high-chromium nickel-based high-temperature alloy 3D printed structure inside the heat treatment process until the surface temperature of the high-chromium nickel-based high-temperature alloy 3D printed structure drops to room temperature.

[0063] Step S703: The high-chromium nickel-based high-temperature alloy 3D printed structural part, which has reached room temperature, is removed from the furnace.

[0064] Thus, by first executing step S701 to cool the high-chromium nickel-based high-temperature alloy 3D printed structure to a preset temperature in a vacuum environment, then by executing step S702 to place the high-chromium nickel-based high-temperature alloy 3D printed structure in an air environment for air cooling, and finally by executing step S703 to remove the high-chromium nickel-based high-temperature alloy 3D printed structure that has reached room temperature from the heat treatment furnace.

[0065] By first lowering the temperature to a lower preset temperature, the probability of oxidation occurring on the surface of the high-chromium nickel-based superalloy 3D-printed structural parts due to contact with air is reduced, thus improving product quality. Furthermore, lowering the temperature to a lower preset temperature before air cooling shortens the cooling time, further improving heat treatment efficiency. Moreover, allowing the high-chromium nickel-based superalloy 3D-printed structural parts to cool to room temperature in the heat treatment furnace before removal avoids injuries caused by excessively high temperatures upon removal, improving safety and reliability.

[0066] Furthermore, in some embodiments, the preset temperature is less than 100°C.

[0067] That is, step S701 is: cooling the high-chromium nickel-based superalloy 3D-printed structural part to below 100°C in a vacuum environment. This not only shortens the air cooling time, but also further reduces the probability of oxidation of the high-chromium nickel-based superalloy 3D-printed structural part when it comes into contact with air, which is conducive to further improving the heat treatment efficiency and the product quality of the high-chromium nickel-based superalloy 3D-printed structural part.

[0068] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0069] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A heat treatment method for 3D-printed structural parts made of high-chromium nickel-based superalloys, characterized in that, Including the following steps: The 3D-printed high-chromium nickel-based superalloy structural part is placed in a heat treatment furnace; the material of the 3D-printed high-chromium nickel-based superalloy structural part is a high-chromium nickel-based superalloy, wherein the mass percentage content of chromium in the high-chromium nickel-based superalloy is ≥32%; The heat treatment furnace is evacuated to ensure that the high-chromium nickel-based high-temperature alloy 3D printed structural parts are in a vacuum environment. The high-chromium nickel-based high-temperature alloy 3D printed structural part is heated for the first time in a vacuum environment until the surface temperature of the high-chromium nickel-based high-temperature alloy 3D printed structural part rises to 600℃±10℃. The high-chromium nickel-based high-temperature alloy 3D printed structural component is kept warm for a first preset time period after the first heating. The high-chromium nickel-based high-temperature alloy 3D printed structural part in a vacuum environment is heated a second time until the surface temperature of the high-chromium nickel-based high-temperature alloy 3D printed structural part rises to 800℃±10℃. The high-chromium nickel-based high-temperature alloy 3D printed structural component is kept warm for a second preset time period after the second heating. The high-chromium nickel-based high-temperature alloy 3D printed structural part was cooled to room temperature.

2. The heat treatment method according to claim 1, characterized in that, The high-chromium nickel-based superalloy comprises the following components in the indicated mass percentages: Cr ≥ 32%, W: 4.3%-5.5%, Mo: 2.3%-3.5%, Al: 0.7%-1.3%, Ti: 0.7%-1.3%, Nb: 0.7%-1.3%, C: 0.03%-0.1%, Fe ≤ 0.5%, B ≤ 0.008%, Ce ≤ 0.03%, Si ≤ 0.3%, S ≤ 0.01%, Y ≤ 0.04%, Ca ≤ 0.02%, and Ni as the balance.

3. The heat treatment method according to claim 1, characterized in that, The step of evacuating the heat treatment furnace is as follows: evacuate the heat treatment furnace until the pressure inside the furnace is less than or equal to 6.7 × 10⁻⁶. -3 Pa.

4. The heat treatment method according to claim 1, characterized in that, The heating rate for both the first and second heating is 5°C / min to 10°C / min.

5. The heat treatment method according to claim 4, characterized in that, The heating rate for both the first and second heating processes is 5°C / min.

6. The heat treatment method according to claim 1, characterized in that, The first preset time period and the second preset time period are the same, both being 2h±15min.

7. The heat treatment method according to claim 1, characterized in that, The step of naturally cooling the high-chromium nickel-based superalloy 3D-printed structural part to room temperature includes the following steps: The high-chromium nickel-based high-temperature alloy 3D printed structural part was cooled to a preset temperature in a vacuum environment; Open the furnace door to air cool the high-chromium nickel-based high-temperature alloy 3D printed structure inside the heat treatment until the surface temperature of the high-chromium nickel-based high-temperature alloy 3D printed structure drops to room temperature. The high-chromium nickel-based superalloy 3D-printed structural component, which has reached room temperature, is now ready for production.

8. The heat treatment method according to claim 7, characterized in that, The preset temperature is less than 100℃.

9. The heat treatment method according to claim 1, characterized in that, The heat treatment furnace has a molybdenum heating screen.

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