Triple forging method for GH4169 alloy

Abstract

The invention relates to the technical field of alloy forging, and discloses a triple forging method for GH4169 alloy. The triple forging method for the GH4169 alloy comprises the following steps that S1, vacuum induction melting and annealing treatment are conducted on alloy raw materials, and a VI M cast ingot is obtained; s2, the VI M cast ingot obtained in the step S1 is subjected to protective atmosphere electroslag remelting and aging treatment, and a PESR cast ingot is obtained; and S3, vacuum consumable melting and aging treatment are conducted on the PESR cast ingot obtained in the step S2, and a VAR cast ingot, namely the GH4169 alloy, is obtained. The GH4169 alloy forged by the triple forging method for the GH4169 alloy, provided by the invention, has excellent mechanical properties and excellent hydrogen embrittlement resistance.

Description

Technical Field

[0001] The invention relates to the technical field of alloy forging, and in particular to a triple forging method for GH4169 alloy. Background Art

[0002] GH4169 alloy is a precipitation-strengthened nickel-based high-temperature alloy. It has excellent mechanical properties and good processing performance in high-temperature environments below 650°C. Therefore, GH4169 alloy is widely used in aerospace, energy and other fields. With the development of the hydrogen energy economy, GH4169 alloy is used in hydrogen-containing environments such as hydrogen-fueled aircraft engines. In this case, the hydrogen embrittlement problem of GH4169 alloy has become the focus of attention of technicians in this field.

[0003] The microstructure of GH4169 alloy is mainly composed of γ matrix and γ', γ" and δ precipitated during the aging process. Studies have shown that the δ precipitate phase can achieve fine grain strengthening of GH4169 alloy by pinning grain boundaries and refining grains. At the same time, the δ precipitate phase can reduce the notch sensitivity of high temperature and long-lasting. Therefore, more δ precipitate phase in GH4169 alloy can effectively improve the mechanical properties of GH4169 alloy in high temperature environment; however, studies have pointed out that the δ precipitate phase is the preferred position for hydrogen-induced cracking of GH4169 alloy. Therefore, in order to improve the hydrogen embrittlement resistance of GH4169 alloy, the amount of δ precipitate phase must be reduced.

[0004] Based on this, regulating the amount of δ precipitation phase and providing a GH4169 alloy with excellent mechanical properties and hydrogen embrittlement resistance in a high-temperature hydrogen-containing environment has become a technical problem that needs to be urgently solved by those skilled in the art. Summary of the invention

[0005] The purpose of the present invention is to provide a triple forging method for GH4169 alloy, and the GH4169 alloy forged by the triple forging method has excellent mechanical properties and hydrogen embrittlement resistance in a high-temperature hydrogen-containing environment.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] One of the technical solutions of the present invention:

[0008] A triple forging method for GH4169 alloy comprises the following steps:

[0009] S1. vacuum induction melting and annealing of the alloy raw materials to obtain a VIM ingot;

[0010] S2. The VIM ingot obtained in step S1 is subjected to protective atmosphere electroslag remelting and aging treatment to obtain a PESR ingot;

[0011] S3. The PESR ingot obtained in step S2 is subjected to vacuum consumable melting and aging treatment to obtain a VAR ingot, namely the GH4169 alloy.

[0012] Furthermore, in step S1, the alloy raw materials include the following raw materials in mass percentage:

[0013] C 0.02%~0.03%, Cr 18%~19%, Ni 52%~55%, Nb 5.2%~5.5%, Mo 3%~3.1%, Al 0.35%~0.65%, Ti 0.8%~1.1%, Fe 16%~19%, and the balance is impurities.

[0014] Further, in step S1, the vacuum induction melting comprises the following steps:

[0015] 1) Weigh each raw material according to the above mass percentage;

[0016] 2) placing the raw materials weighed in step 1) except niobium, titanium and aluminum in a vacuum induction furnace, evacuating the vacuum induction furnace to a vacuum state, and performing electro-melting;

[0017] 3) After the electric melting in step 2) is completed, the alloy is refined once, and then the niobium, titanium and aluminum raw materials weighed in step 1) are added, and refined twice. After the secondary refining is completed, the alloy liquid is poured into an ingot mold.

[0018] Furthermore, in step 2), when placing the raw materials other than niobium, titanium and aluminum in the vacuum induction furnace, metal nickel, metal chromium, metal iron and carbon need to be mixed and placed at the bottom of the vacuum induction furnace, and molybdenum bars need to be laid flat on the surface of the above raw materials.

[0019] Furthermore, in step 2), the vacuum degree in the vacuum induction furnace is 10Pa.

[0020] Furthermore, in step 2), the temperature and time of the electric melting are: 900°C for 2h, 1500°C for 20min, 1300°C for 10min, and 1700°C for 20min.

[0021] Furthermore, in step 3), the temperature of the primary refining is 1500° C., the vacuum degree is 5 Pa, and the duration is 1 hour.

[0022] Furthermore, in step 3), the secondary refining temperature is 1450° C., the vacuum degree is 5 Pa, and the duration is 3 hours.

[0023] Furthermore, in step 3), before the pouring, the temperature in the vacuum induction furnace needs to be raised to 1500° C. and kept warm for 10 minutes.

[0024] Furthermore, in step 3), the pouring temperature is 1480°C.

[0025] Furthermore, in step S1, the temperature and time of the annealing treatment are: 550°C for 2h, 700°C for 1h, 300°C for 2h, 500°C for 1h, and 150°C for 1h.

[0026] Further, in step S2, the protective atmosphere electroslag remelting comprises the following steps:

[0027] The VIM ingot obtained in step S1 is placed in an electroslag remelting furnace and 15 wt.% CaF is added. 2 -CaO-Al 2 O 3 In the ternary slag system, argon is used as the protective gas, the melting rate is controlled at 200kg / h, and the VIM ingot is electroslag remelted.

[0028] Furthermore, the CaF 2 -CaO-Al 2 O 3 In the ternary slag system, CaF 2 , CaO and Al 2 O 3 The mass ratio is 2:1:1.

[0029] Furthermore, in step S2, before the aging treatment, the VIM ingot needs to be naturally cooled to 300°C.

[0030] Furthermore, in step S2, the temperature and time of the aging treatment are: 300°C for 10 min, 500°C for 20 min, and 200°C for 10 min.

[0031] Further, in step S3, the vacuum consumable smelting comprises the following steps:

[0032] The PESR ingot obtained in step S2 is placed in a vacuum consumable arc melting furnace with a vacuum degree of 10 Pa, the melting rate is controlled to be 150 kg / h, the droplet is 5 / s, and the PESR ingot is subjected to vacuum consumable melting.

[0033] Furthermore, in step S3, before the aging treatment, the PESR ingot needs to be naturally cooled to 300°C.

[0034] Furthermore, in step S3, the temperature and time of the aging treatment are: 100°C for 20 min, 150°C for 60 min, and 50°C for 20 min.

[0035] The second technical solution of the present invention:

[0036] The triple forged GH4169 alloy is forged by the triple forging method for the GH4169 alloy.

[0037] The third technical solution of the present invention:

[0038] The above-mentioned application of triple forged GH4169 alloy in high temperature hydrogen-containing environment.

[0039] Compared with the prior art, the present invention has the following beneficial effects:

[0040] The GH4169 alloy forged by the triple forging method for GH4169 alloy provided by the present invention has excellent mechanical properties and fully meets the mechanical property requirements under high temperature conditions specified in GB / T40303-2021;

[0041] The GH4169 alloy forged by a triple forging method for the GH4169 alloy provided by the present invention has excellent hydrogen embrittlement resistance. DETAILED DESCRIPTION

[0042] Now, various exemplary embodiments of the present invention are described in detail, and this detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.

[0043] In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0044] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0045] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.

[0046] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0047] Example

[0048] A triple forged GH4169 alloy

[0049] 1. Vacuum Induction Melting (VIM)

[0050] 1) Weigh each raw material according to the following mass percentage;

[0051] C 0.025%, Cr 18%, Ni 52.5%, Nb 5.3%, Mo 3%, Al 0.4%, Ti 1%, Fe16.6%, the balance is impurities;

[0052] 2) placing the raw materials weighed in step 1) except niobium, titanium and aluminum into a vacuum induction furnace, wherein metal nickel, metal chromium, metal iron and carbon need to be mixed and placed at the bottom of the vacuum induction furnace, and molybdenum bars need to be laid flat on the surface of the above raw materials;

[0053] 3) The vacuum induction furnace containing the raw materials in step 2) is evacuated to a vacuum degree of 10 Pa, and electromelted. The electromelting temperature and time are: 900°C for 2h, 1500°C for 20min, 1300°C for 10min, and 1700°C for 20min.

[0054] 4) After the electric melting in step 3) is completed, the temperature of the vacuum induction furnace after the gradient electric melting in step 3) is adjusted to 1500° C., the vacuum degree is 5 Pa, electromagnetic stirring is turned on, and the primary refining is performed for 1 hour, and then the niobium, titanium and aluminum raw materials weighed in step 1) are added, the temperature of the vacuum induction furnace is adjusted to 1450° C., the vacuum degree is 5 Pa, electromagnetic stirring is turned on, and secondary refining is performed for 3 hours;

[0055] 5) After the secondary refining in step 4) is completed, the temperature in the vacuum induction furnace is raised to 1500° C. and kept warm for 10 minutes, and then the pouring temperature is controlled to 1480° C., and the alloy liquid is poured into an ingot mold of Φ330 mm;

[0056] 6) transferring the ingot mold poured with the alloy liquid in step 5) to an annealing furnace for annealing, wherein the annealing temperature and time are: 550° C. for 2 h, 700° C. for 1 h, 300° C. for 2 h, 500° C. for 1 h, and 150° C. for 1 h, to obtain a VIM ingot;

[0057] 2. Protective atmosphere electroslag remelting (PESR)

[0058] 1) Grind the VIM ingot obtained in step 1, cut the head and tail, and then place the VIM ingot in an electroslag remelting furnace and add 15wt.% CaF2 -CaO-Al 2 O 3 Ternary slag system (CaF 2 ∶CaO∶Al 2 O 3 =2:1:1, m:m:m), using argon as the protective gas, controlling the melting rate to 200kg / h, and performing electroslag remelting on the VIM ingot;

[0059] 2) After the electroslag remelting in step 1) is completed, the VIM ingot is naturally cooled to 300° C., and then the VIM ingot is subjected to aging treatment, and the temperature and time of the aging treatment are: 300° C. for 10 min, 500° C. for 20 min, and 200° C. for 10 min, to obtain a PESR ingot;

[0060] 3. Vacuum Autoclave Remelting (VAR)

[0061] 1) grinding the PESR ingot obtained in step 2, cutting the head and tail, and then placing the PESR ingot in a vacuum consumable arc melting furnace with a vacuum degree of 10 Pa, controlling the melting rate to 150 kg / h and the droplet to 5 / s, and performing vacuum consumable melting on the PESR ingot;

[0062] 2) After the vacuum consumable smelting in step 1) is completed, the PESR ingot is naturally cooled to 300° C., and the PESR ingot is subjected to aging treatment. The temperature and time of the aging treatment are: 100° C. for 20 min, 150° C. for 60 min, and 50° C. for 20 min, respectively, to obtain a VAR ingot, i.e., the triple forged GH4169 alloy.

[0063] Comparative Example 1

[0064] A GH4169 alloy

[0065] Same as the embodiment, except that the vacuum induction melting in step 1 is as follows:

[0066] 1) Weigh each raw material according to the following mass percentage;

[0067] Ni 52%, Cr 19%, Fe 19%, Nb 5.2%, Mo 2.5%, Ti 1%, Al 1%, C 0.02%, the balance is impurities;

[0068] 2) placing the raw materials weighed in step 1) except niobium, titanium and aluminum into a vacuum induction furnace, wherein metal nickel, metal chromium, metal iron and carbon need to be mixed and placed at the bottom of the vacuum induction furnace, and molybdenum bars need to be laid flat on the surface of the above raw materials;

[0069] 3) The vacuum induction furnace containing the raw materials in step 2) is evacuated to a vacuum degree of 10 Pa, and electromelted. The electromelting temperature and time are: 900°C for 2h, 1500°C for 20min, 1300°C for 10min, and 1700°C for 20min.

[0070] 4) After the electric melting in step 3) is completed, the temperature of the vacuum induction furnace after the gradient electric melting in step 3) is adjusted to 1500° C., the vacuum degree is 5 Pa, electromagnetic stirring is turned on, and the primary refining is performed for 1 hour, and then the niobium, titanium and aluminum raw materials weighed in step 1) are added, the temperature of the vacuum induction furnace is adjusted to 1450° C., the vacuum degree is 5 Pa, electromagnetic stirring is turned on, and secondary refining is performed for 3 hours;

[0071] 5) After the secondary refining in step 4) is completed, the temperature in the vacuum induction furnace is raised to 1500° C. and kept warm for 10 minutes. Then, the pouring temperature is controlled to 1480° C., and the alloy liquid is poured into a Φ330 mm ingot mold and cooled naturally to obtain a VIM ingot.

[0072] Comparative Example 2

[0073] A GH4169 alloy

[0074] The same as the embodiment, except that the protective atmosphere electroslag remelting in step 2 is:

[0075] The VIM ingot obtained in step 1 was polished, the head and tail were cut, and then the VIM ingot was placed in an electroslag remelting furnace and 15wt.% CaF was added. 2 -CaO-Al 2 O 3 Ternary slag system (CaF 2 ∶CaO∶Al 2 O 3 =2:1:1, m:m:m), argon is used as the protective gas, the melting rate is controlled at 200kg / h, the VIM ingot is electroslag remelted to obtain a PESR ingot.

[0076] Comparative Example 3

[0077] A GH4169 alloy

[0078] The same as the embodiment, the only difference is that the vacuum consumable melting in step 3 is:

[0079] The PESR ingot obtained in step 2 is polished, the head and tail are cut, and then the PESR ingot is placed in a vacuum consumable arc melting furnace with a vacuum degree of 10 Pa, the melting rate is controlled to be 150 kg / h, and the droplet is 5 / s. The PESR ingot is vacuum consumable melted to obtain a VAR ingot, namely the GH4169 alloy.

[0080] The mechanical properties of the GH4169 alloys forged in the embodiment and comparative examples 1 to 3 were tested at a high temperature of 650° C. The results of the mechanical properties test are shown in Table 1.

[0081] Table 1 Mechanical properties test results

[0082]

[0083] It can be seen from the data in Table 1 that the GH4169 alloy forged by the triple forging method for GH4169 alloy provided by the present invention has excellent mechanical properties; while the GH4169 alloys forged by comparative examples 1 to 3, that is, omitting the annealing treatment after vacuum induction melting, omitting the aging treatment after protective atmosphere electroslag remelting, and omitting the aging treatment after vacuum consumable melting, have no significant difference in mechanical properties compared with the GH4169 alloy prepared in the embodiment, but there is a slight downward trend. The study found that the reason is that, when the ingot is annealed and aged, the γ' precipitation phase is gradually converted from the DO22 structure to the DOa structure, forming the δ precipitation phase, and with the increase in the number of the δ precipitation phase, the mechanical properties in a high temperature environment will decrease, but the decrease is not obvious, which fully meets the mechanical properties requirements under high temperature conditions specified in GB / T40303-2021.

[0084] The GH4169 alloy forged in Example and Comparative Examples 1 to 3 was tested for hydrogen embrittlement resistance. The method for testing hydrogen embrittlement resistance is as follows:

[0085] Under high temperature conditions of 650℃, hydrogen ions were implanted into the surface of GH4169 alloy by electrochemical method, and then the mechanical properties of GH4169 alloy were tested under high temperature conditions of 650℃.

[0086] The test results of hydrogen embrittlement resistance are shown in Table 2;

[0087] Table 2 Hydrogen embrittlement resistance test results

[0088]

[0089] It can be seen from the data in Table 1 and Table 2 that the GH4169 alloy forged by the triple forging method for GH4169 alloy provided by the present invention has excellent hydrogen embrittlement resistance; after electrochemical hydrogen ion implantation, the GH4169 alloy prepared in the embodiment has a much smaller decrease in mechanical properties than the GH4169 alloy forged in Comparative Examples 1 to 3, that is, the annealing treatment after vacuum induction melting, the aging treatment after protective atmosphere electroslag remelting, and the aging treatment after vacuum consumable melting are omitted. The study found that the reason is that, when the ingot is annealed and aged, the γ' precipitate phase is gradually converted from the DO22 structure to the DOa structure, forming the δ precipitate phase, and as the amount of the δ precipitate phase increases, the hydrogen embrittlement resistance is significantly improved.

[0090] 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 above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A triple forging method for GH4169 alloy, characterized in that: The following steps are involved: S1. vacuum induction melting and annealing of the alloy raw materials to obtain a VIM ingot; S2. The VIM ingot obtained in step S1 is subjected to protective atmosphere electroslag remelting and aging treatment to obtain a PESR ingot; S3. The PESR ingot obtained in step S2 is subjected to vacuum consumable melting and aging treatment to obtain a VAR ingot, namely the GH4169 alloy.

2. A triple forging method for GH4169 alloy according to claim 1, characterized in that: In step S1, the alloy raw materials include the following raw materials in mass percentage: C 0.02%~0.03%, Cr 18%~19%, Ni 52%~55%, Nb 5.2%~5.5%, Mo 3%~3.1%, Al 0.35%~0.65%, Ti 0.8%~1.1%, Fe 16%~19%, and the balance is impurities.

3. A triple forging method for GH4169 alloy according to claim 1, characterized in that: In step S1, the vacuum induction melting comprises the following steps: 1) Weigh each raw material according to the above mass percentage; 2) placing the raw materials weighed in step 1) except niobium, titanium and aluminum in a vacuum induction furnace, evacuating the vacuum induction furnace to a vacuum state, and performing electro-melting; 3) After the electric melting in step 2) is completed, the alloy is refined once, and then the niobium, titanium and aluminum raw materials weighed in step 1) are added, and refined twice. After the secondary refining is completed, the alloy liquid is poured into an ingot mold.

4. A triple forging method for GH4169 alloy according to claim 3, characterized in that: In step 2), the vacuum degree in the vacuum induction furnace is 10Pa; the temperature and time of the electric melting are: 900℃2h, 1500℃20min, 1300℃10min, 1700℃20min respectively; in step 3), the temperature of the first refining is 1500℃, the vacuum degree is 5Pa, and the duration is 1h; the temperature of the second refining is 1450℃, the vacuum degree is 5Pa, and the duration is 3h; before the pouring, the temperature in the vacuum induction furnace needs to be raised to 1500℃ and kept warm for 10min; the pouring temperature is 1480℃.

5. A triple forging method for GH4169 alloy according to claim 1, characterized in that: In step S1, the temperature and time of the annealing treatment are: 550°C for 2h, 700°C for 1h, 300°C for 2h, 500°C for 1h, and 150°C for 1h.

6. A triple forging method for GH4169 alloy according to claim 1, characterized in that: In step S2, the protective atmosphere electroslag remelting comprises the following steps: The VIM ingot obtained in step S1 is placed in an electroslag remelting furnace, and 15wt.% of CaF2-CaO-Al2O3 ternary slag system is added, argon is used as a protective gas, the melting rate is controlled to be 200kg / h, and the VIM ingot is electroslag remelted.

7. A triple forging method for GH4169 alloy according to claim 1, characterized in that: In step S2, before the aging treatment, the VIM ingot needs to be naturally cooled to 300°C; the temperature and time of the aging treatment are: 300°C for 10 min, 500°C for 20 min, and 200°C for 10 min.

8. A triple forging method for GH4169 alloy according to claim 1, characterized in that: In step S3, the vacuum consumable smelting includes the following steps: The PESR ingot obtained in step S2 is placed in a vacuum consumable arc melting furnace with a vacuum degree of 10 Pa, the melting rate is controlled to be 150 kg / h, the droplet is 5 / s, and the PESR ingot is subjected to vacuum consumable melting.

9. A triple forging method for GH4169 alloy according to claim 1, characterized in that: In step S3, before the aging treatment, the VIM ingot needs to be naturally cooled to 300°C; the temperature and time of the aging treatment are: 100°C for 20 min, 150°C for 60 min, and 50°C for 20 min.

10. A triple forged GH4169 alloy forged by the triple forging method for GH4169 alloy as claimed in any one of claims 1 to 9.

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