Solid solution treatment method for additive manufacturing of GH3625 alloy

Abstract

The invention relates to the technical field of additive manufacturing, in particular to a solid solution treatment method for additive manufacturing of GH3625 alloy. The solid solution treatment method for additive manufacturing of the GH3625 alloy comprises the following steps that an additive manufacturing GH3625 alloy part is subjected to heat preservation treatment at the temperature of 650-750 DEG C, then the temperature is increased to 950-1050 DEG C, heat preservation treatment is conducted, and then furnace cooling is conducted. According to the special microstructure of the additive manufacturing GH3625 alloy, a solution treatment system suitable for additive manufacturing of the GH3625 alloy is designed in a targeted mode, the deformation cracking risk of the additive manufacturing GH3625 alloy part in the solution treatment stage can be greatly reduced, and the comprehensive mechanical property is remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of additive manufacturing, and in particular to a solid solution treatment method for additively manufacturing a GH3625 alloy. Background Art

[0002] GH3625 alloy is a solid solution strengthened nickel-based deformable high temperature alloy with excellent tensile and fatigue properties, good mechanical properties from low temperature to 980℃, and excellent corrosion resistance. It can be widely used in the manufacture of key components of aerospace engines, chemical equipment, etc. With the development of aerospace and other fields, the structural complexity of key components has increased. The use of traditional processing methods such as casting and forging has problems such as difficult design and long processing cycle, which restricts the development of aerospace and other fields.

[0003] Compared with traditional processing methods, additive manufacturing has the advantages of rapid processing and forming of complex parts, shortening product development cycles, and improving material utilization, and has gradually become one of the important ways to manufacture key aerospace components. However, due to the rapid cooling molding characteristics of additive manufacturing, the deposited microstructure of additively manufactured GH3625 alloy is significantly different from the microstructure of castings and forgings, and the conventional heat treatment system cannot meet the organizational and mechanical property requirements of additively manufactured GH3625 alloy.

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

[0005] The purpose of the present invention is to provide a solution treatment method for additively manufactured GH3625 alloy, which can reduce the risk of deformation and cracking, and can improve the mechanical properties of additively manufactured GH3625 alloy and reduce the difference in transverse and longitudinal mechanical properties.

[0006] In order to achieve the above-mentioned object of the present invention, the present invention provides a solution treatment method for additively manufacturing GH3625 alloy, comprising the following steps:

[0007] The additively manufactured GH3625 alloy parts are heat-treated at 650-750°C, then heated to 950-1050°C for heat-treatment, and then cooled in the furnace.

[0008] In a specific embodiment of the present invention, the time of heat preservation treatment at 950-1050° C. is 60-120 minutes.

[0009] In a specific embodiment of the present invention, the time of heat preservation treatment at 650-750° C. is 240-360 minutes.

[0010] In a specific embodiment of the present invention, during the heat treatment at 950-1050°C, the heating rate is 5°C / min.

[0011] In a specific embodiment of the present invention, during the solution treatment, the additively manufactured GH3625 alloy part is charged into a furnace at room temperature. Further, the temperature is increased from room temperature to 650-750°C at a heating rate of 5°C / min.

[0012] In a specific embodiment of the present invention, the additively manufactured GH3625 alloy part has a thin-walled structure. Furthermore, the wall thickness of the thin-walled structure is 0.5 to 1.0 mm.

[0013] In a specific embodiment of the present invention, the additive manufacturing method for preparing GH3625 alloy parts includes: 3D printing GH3625 alloy powder under vacuum or protective atmosphere; the power of the 3D printing is 220 to 340 W, and the scanning speed of the 3D printing is 800 to 1100 mm / s.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] According to the microstructure of the additively manufactured GH3625 alloy, the present invention specifically designs a solution treatment system suitable for the additively manufactured GH3625 alloy, which can greatly reduce the deformation and cracking risks of the additively manufactured GH3625 alloy parts during the solution treatment stage, evenly refine the microstructure after the solution treatment, and significantly improve the comprehensive mechanical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 A comparison chart of the tensile strength of the horizontally printed samples provided by the present invention after solution treatment according to the embodiment and the comparative example;

[0018] Figure 2 This is a comparison chart of the yield strength of the longitudinally printed samples provided by the present invention after solution treatment according to the embodiments and comparative examples. DETAILED DESCRIPTION

[0019] The technical scheme of the present invention will be clearly and completely described below in conjunction with the accompanying drawings and specific embodiments, but it will be understood by those skilled in the art that the following described embodiments are part of embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be considered as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to normal conditions or conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0020] According to the Handbook of High-temperature Alloys, the solution heat treatment system for GH3625 alloy castings or forgings is 1090-1200℃ / AC or WQ. Due to the rapid cooling molding characteristics of additive manufacturing, the deposited microstructure of additively manufactured GH3625 is significantly different from the microstructure of castings and forgings, with strong anisotropy and high residual stress. Conventional heat treatment not only has a high risk of deformation and cracking of the alloy parts, but the corresponding physical and chemical test results cannot meet the performance requirements of key component materials for existing aerospace engines. In addition, for additively manufactured GH3625 alloy parts, especially for large thin-walled parts, the existing solution heat treatment system is difficult to control the shape, and the mechanical properties in the transverse and longitudinal directions are greatly different. Based on this, the present invention designs a solution treatment system suitable for additively manufactured GH3625 alloy parts according to the microstructure of the additively manufactured GH3625 alloy, so as to reduce the risk of deformation and cracking and significantly improve its comprehensive mechanical properties.

[0021] The present invention provides a solution treatment method for additively manufacturing GH3625 alloy, comprising the following steps:

[0022] The additively manufactured GH3625 alloy parts are heat-treated at 650-750°C, then heated to 950-1050°C for heat-treatment, and then cooled in the furnace.

[0023] In the solution treatment of the present invention, the additively manufactured GH3625 alloy part is first subjected to a heat preservation treatment at 650-750°C to eliminate or reduce the residual stress of the alloy part, on the one hand to avoid cracking and deformation problems in the subsequent temperature rise solution process, and on the other hand to obtain a uniform and fine grain size with a relatively low solution temperature of 950-1050°C. At the same time, after the heat preservation treatment, the furnace cooling method is adopted to make the solid solution precipitate uniform and dispersed carbides, thereby improving the mechanical properties.

[0024] For example, in different embodiments, the GH3625 alloy part can be first subjected to heat preservation treatment at 650°C, 700°C, 750°C or any two thereof, and then heated to 950°C, 980°C, 1000°C, 1020°C, 1050°C or any two thereof for heat preservation treatment.

[0025] In a specific embodiment of the present invention, the time of heat preservation treatment at 950-1050° C. is 60-120 minutes.

[0026] The holding time at 950-1050°C is adjusted within the above range to ensure uniformity of structure and composition and avoid coarse grains. For example, in different embodiments, the holding time at 950-1050°C can be 60 min, 90 min, 120 min, or any two thereof.

[0027] In a specific embodiment of the present invention, the time of heat preservation treatment at 650-750° C. is 240-360 minutes.

[0028] Adjust the holding time of the 650-750℃ stage within the above range to fully eliminate or reduce the residual stress of the alloy parts and improve the deformation and cracking problems; then heat it to the solid solution temperature, and cooperate with the furnace cooling method to further control the deformation and cracking problems of the solid solution treatment, improve the mechanical properties and improve the anisotropy problem. For example, in different embodiments, the holding time of 650-750℃ can be 240min, 300min, 360min or any two of them.

[0029] In a specific embodiment of the present invention, during the heat treatment at 950-1050° C., the heating rate is 5° C. / min.

[0030] Use an appropriate heating rate to avoid excessive stress inside the alloy during the heating process, which may cause deformation or cracks, while ensuring that the alloy grain size is small and improving strength and toughness. The heating rate is 5°C / min from 650-750°C to 950-1050°C.

[0031] In a specific embodiment of the present invention, the temperature is increased from room temperature to 650-750° C. at a heating rate of 5° C. / min.

[0032] In a specific embodiment of the present invention, during the solution treatment, the additively manufactured GH3625 alloy part is loaded into a furnace at room temperature.

[0033] In a specific embodiment of the present invention, the additively manufactured GH3625 alloy part has a thin-walled structure. Further, the wall thickness of the thin-walled structure is 0.5 to 1.0 mm.

[0034] Due to the rapid cooling forming characteristics of additively manufactured GH3625 alloy parts, deformation and cracking problems are prone to occur during the solution treatment stage. Especially for large thin-walled parts with thin-walled structures, shape control is more difficult, and the difference in mechanical properties in the transverse and longitudinal directions is greater. The present invention adopts a suitable heating process, a suitable solution temperature and a specific cooling method, which not only effectively controls the deformation and cracking problems of additively manufactured GH3625 alloy parts, but also prevents large thin-walled parts with thin-walled structures from deformation and cracking during the solution treatment of the present invention, and can also improve the mechanical properties.

[0035] In a specific embodiment of the present invention, the preparation method of the additively manufactured GH3625 alloy part includes: 3D printing the GH3625 alloy powder under vacuum or protective atmosphere; the power of the 3D printing is 220 to 340 W, and the scanning speed of the 3D printing is 800 to 1100 mm / s.

[0036] The GH3625 alloy powder of the present invention can be prepared by conventional methods, such as vacuum melting and gas atomization, but not limited thereto. The particle size of the alloy powder used for 3D printing can be 15 to 53 μm.

[0037] The GH3625 alloy powder of the present invention comprises the following components in percentage by mass: Cr 20%-23%, Fe≤5%, C≤0.1%, Mn≤0.5%, Si≤0.5%, Mo 8%-10.0%, Cu≤0.07%, Co≤1%, Al≤0.4%, Ti≤0.4%, Nb 3.15%-4.15%, P≤0.015%, S≤0.015%, and the balance is Ni.

[0038] The preparation method of the additively manufactured GH3625 alloy parts used in the following embodiments of the present invention is as follows, but is not limited thereto.

[0039] The preparation method of additively manufactured GH3625 alloy parts includes: using GH3625 alloy powder with a particle size of 15 to 53 μm to prepare a 3D printed sample using an SLM process, and the 3D printing process parameters are: 3D printing power is 300 W, 3D printing scanning speed is 1000 mm / s, 3D printing spot diameter is 0.09 mm, 3D printing scanning spacing is 0.11 mm, and 3D printing powder layer thickness is 0.06 mm.

[0040] In actual operation, in order to verify the performance of horizontal printing and vertical printing, horizontal printing samples and vertical printing samples can be prepared respectively according to the above 3D printing process parameters.

[0041] Example 1

[0042] The present embodiment provides a solution treatment method for additively manufactured GH3625 alloy, comprising the following steps: charging the additively manufactured GH3625 alloy sample into a furnace at room temperature, then heating the temperature to 750°C at a heating rate of 5°C / min and keeping the temperature for 300 min, then heating the temperature to 1000°C at a heating rate of 5°C / min and keeping the temperature for 60 min, and then cooling with the furnace.

[0043] Example 2

[0044] The present embodiment provides a solution treatment method for additively manufactured GH3625 alloy, comprising the following steps: charging the additively manufactured GH3625 alloy sample into a furnace at room temperature, then heating the temperature to 750°C at a heating rate of 5°C / min and keeping the temperature for 360 min, then heating the temperature to 1000°C at a heating rate of 5°C / min and keeping the temperature for 120 min, and then cooling the temperature with the furnace.

[0045] Example 3

[0046] The present embodiment provides a solution treatment method for additively manufactured GH3625 alloy, comprising the following steps: charging the additively manufactured GH3625 alloy sample into a furnace at room temperature, then heating the temperature to 700°C at a heating rate of 5°C / min and keeping the temperature for 240 min, then heating the temperature to 980°C at a heating rate of 5°C / min and keeping the temperature for 60 min, and then cooling with the furnace.

[0047] Example 4

[0048] The present embodiment provides a solution treatment method for additively manufactured GH3625 alloy, comprising the following steps: charging the additively manufactured GH3625 alloy sample into a furnace at room temperature, then heating the temperature to 700°C at a heating rate of 5°C / min and keeping the temperature for 300 min, then heating the temperature to 980°C at a heating rate of 5°C / min and keeping the temperature for 120 min, and then cooling with the furnace.

[0049] Example 5

[0050] The present embodiment provides a solution treatment method for additively manufactured GH3625 alloy, comprising the following steps: charging an additively manufactured GH3625 alloy sample into a furnace at room temperature, then heating the temperature to 650°C at a heating rate of 5°C / min and keeping the temperature for 360 min, then heating the temperature to 950°C at a heating rate of 5°C / min and keeping the temperature for 60 min, and then cooling the temperature with the furnace.

[0051] Example 6

[0052] The present embodiment provides a solution treatment method for additively manufactured GH3625 alloy, comprising the following steps: charging an additively manufactured GH3625 alloy sample into a furnace at room temperature, then heating the temperature to 650°C at a heating rate of 5°C / min and keeping the temperature for 240 min, then heating the temperature to 950°C at a heating rate of 5°C / min and keeping the temperature for 120 min, and then cooling the furnace.

[0053] Comparative Example 1

[0054] Comparative Example 1 provides a solution treatment method for additively manufactured GH3625 alloy, comprising the following steps: charging the additively manufactured GH3625 alloy sample into a furnace at room temperature, then heating the temperature to 1100°C at a heating rate of 5°C / min and keeping the temperature for 60 minutes, and then cooling with argon gas.

[0055] Comparative Example 2

[0056] Comparative Example 2 provides a solution treatment method for additively manufactured GH3625 alloy, comprising the following steps: charging the additively manufactured GH3625 alloy sample into a furnace at room temperature, then heating the temperature to 750°C at a heating rate of 5°C / min and keeping the temperature for 360 min, then heating the temperature to 1100°C at a heating rate of 5°C / min and keeping the temperature for 60 min, and then cooling with argon gas.

[0057] Comparative Example 3

[0058] Comparative Example 3 provides a solution treatment method for additively manufactured GH3625 alloy, comprising the following steps: charging the additively manufactured GH3625 alloy sample into a furnace at room temperature, then heating the temperature to 1100°C at a heating rate of 5°C / min and keeping the temperature for 60 minutes, and then cooling the furnace.

[0059] Comparative Example 4

[0060] Comparative Example 4 provides a solution treatment method for additively manufactured GH3625 alloy, comprising the following steps: charging the additively manufactured GH3625 alloy sample into a furnace at room temperature, then heating the temperature to 750°C at a heating rate of 5°C / min and keeping the temperature for 360 min, then heating the temperature to 1100°C at a heating rate of 5°C / min and keeping the temperature for 60 min, and then cooling the furnace.

[0061] Comparative Example 5

[0062] Comparative Example 5 provides a solution treatment method for additively manufactured GH3625 alloy, comprising the following steps: charging the additively manufactured GH3625 alloy sample into a furnace at room temperature, then heating the temperature to 750°C at a heating rate of 5°C / min and keeping the temperature for 360 min, then heating the temperature to 1050°C at a heating rate of 5°C / min and keeping the temperature for 60 min, and then cooling with argon gas.

[0063] Experimental example

[0064] In order to compare and illustrate the deformation and cracking problems of solution treatment in different embodiments and comparative examples, the GH3625 alloy parts after solution treatment in different embodiments and comparative examples are compared. The test results are shown in Table 1. Insulation at the low temperature step and slow cooling rate are helpful to control the deformation of parts.

[0065] Table 1 Deformation and cracking of different embodiments and comparative examples after solution treatment

[0066]

[0067]

[0068] The room temperature tensile properties of the alloy samples after solution treatment of different embodiments of the present invention and comparative examples were tested. The room temperature tensile properties were tested in accordance with GB / T 228.1. The test results are shown in Table 2. The room temperature tensile strength of the embodiments is significantly higher than that of the comparative examples, and the plasticity is only slightly reduced relative to the comparative examples.

[0069] Table 2 Room temperature tensile properties test results after solution treatment of different embodiments and comparative examples

[0070]

[0071]

[0072] It can be seen from the above test results that the solid solution treatment of the present invention not only greatly reduces the risk of deformation and cracking of the alloy parts, making the products meet strict dimensional requirements, but also significantly improves the tensile strength of the alloy parts. At the same time, the reduction in plasticity is controlled within a small range, and the comprehensive mechanical properties are significantly improved.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A solution treatment method for additively manufacturing GH3625 alloy, characterized in that: The steps include: The additively manufactured GH3625 alloy parts are heat-treated at 650-750°C, then heated to 950-1050°C for heat-treatment, and then cooled in the furnace.

2. The solution treatment method according to claim 1, characterized in that: The heat preservation time at 950-1050°C is 60-120 minutes.

3. The solution treatment method according to claim 1, characterized in that: The time of heat preservation treatment at 650-750°C is 240-360 minutes.

4. The solution treatment method according to claim 1, characterized in that: During the heat-raising treatment to 950-1050° C., the heating rate is 5° C. / min.

5. The solution treatment method according to claim 1, characterized in that: The temperature was raised from room temperature to 650-750°C at a heating rate of 5°C / min.

6. The solution treatment method according to claim 1, characterized in that: During the solution treatment, the additively manufactured GH3625 alloy part is loaded into a furnace at room temperature.

7. The solution treatment method according to claim 1, characterized in that: The additively manufactured GH3625 alloy part has a thin-wall structure, and the wall thickness of the thin-wall structure is 0.5-1.0 mm.

8. The solution treatment method according to claim 1, characterized in that: The additively manufactured GH3625 alloy parts after solution treatment meet the following requirements: Room temperature tensile properties of GH3625 alloy parts printed horizontally and vertically, tensile strength Rm ≥ 830MPa, yield strength Rp 0.2 ≥410MPa, elongation A≥30%.

9. The solution treatment method according to claim 1, characterized in that: The preparation of the additively manufactured GH3625 alloy part includes: 3D printing GH3625 alloy powder under vacuum or protective atmosphere; the power of the 3D printing is 220 to 340 W, and the scanning speed of the 3D printing is 800 to 1100 mm / s.

Images