High-temperature alloy material for turbine disc and preparation method of high-temperature alloy material

Abstract

The invention discloses a high-temperature alloy material for a turbine disc and a preparation method of the high-temperature alloy material, and belongs to the technical field of high-temperature alloy materials. The pure and uniform steel ingot is obtained through vacuum induction furnace smelting and vacuum consumable remelting, the round steel material with the uniform structure is obtained after heat treatment through the optimized heating system, the optimized forging technology, the optimized forging heating temperature and the optimized heat preservation measure in the forging process, and the grain size grade difference of the cross section and the longitudinal face of the obtained round steel material does not exceed 1.0 grade; and the average grain size reaches 3.0 grade, and good transverse mechanical property and high-temperature durability are achieved. According to the high-temperature alloy material produced through the method, the lasting fracture time is longer than 170 h, the room-temperature tensile strength is larger than 1400 Mpa, and the performance requirement of the high-temperature alloy for the turbine disc can be well met.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of high-temperature alloy materials and methods, and particularly relates to a high-temperature alloy material for a turbine disc and a preparation method thereof. BACKGROUND

[0002] As a Ni-Cr-Co-based precipitation hardening type wrought high-temperature alloy, GH4742 alloy becomes an ideal material for manufacturing high-temperature load-bearing components such as turbine disc blades due to its high creep and rupture strength in the range of 650 DEG C to 800 DEG C, good comprehensive ability and organizational stability. With the progress of aerospace technology and the growth of energy production demand, GH4742 alloy plays an important role in key fields such as advanced aero-engines and marine gas turbines, and these applications put forward higher requirements for material performance, therefore, there is a key demand for GH4742 alloy with excellent performance in the market.

[0003] However, the manufacturing process of GH4742 alloy is complex, involving advanced smelting technologies such as vacuum induction melting and vacuum consumable remelting, as well as precise heat treatment processes, and the application of these technologies is crucial to improve the performance of the alloy, therefore, there are difficulties and deficiencies in the smelting of the alloy in technology. With the increasing demand for high-performance high-temperature alloys at home and abroad, the market potential of GH4742 alloy is huge, and enterprises can improve the market competitiveness and economic benefits of products through process development. In summary, the process development of GH4742 alloy is to meet the demand for high-performance materials in the fields of aerospace, energy and the like, to improve the performance of materials through technological innovation, to expand the application fields, and to enhance the market competitiveness of enterprises.

[0004] There are the following problems in the preparation and forming of GH4742 alloy: in the preparation aspect, in the VAR process of double smelting (VIM+VAR), the uneven VAR cooling rate leads to coarse dendrites and serious Nb / Ti segregation, forming coarse carbides and affecting the uniformity of the structure. In the forming aspect, the alloy has a narrow hot deformation window, the dynamic recrystallization behavior is complex, the grain size and gamma prime phase distribution are difficult to be cooperatively controlled, and cracks are easily induced. In particular, the preparation of large-size rods (≥φ300 mm) still faces the challenges of segregation and uniformity of the structure.

[0005] Therefore, how to improve the performance of the high-temperature alloy material for a turbine disc becomes a technical problem to be solved. SUMMARY

[0006] The purpose of the present application is to solve the above problems, and to provide a high-temperature alloy material for a turbine disc and a preparation method thereof to meet the use requirements in complex working environments. The technical purpose of the present application is to provide a high-temperature alloy material for a turbine disc and a preparation method thereof, which has good high-temperature creep resistance, high grain size, small difference between transverse and longitudinal performance, good structure uniformity and small difference in grain size.

[0007] To achieve the above technical purposes, the technical scheme adopted by the present application is as follows: One of the purposes of the present application is to provide a preparation method of a high-temperature alloy turbine disc material, the high-temperature alloy turbine disc material comprising the following element components in percentage by weight: C: ≤0.08%, Cr: 13.0-15.0%, Co: 9.0-11.0%, Mo: 4.5-5.5%, Fe: ≤0.5%, Nb: 2.4-2.8%, Al: 2.4-2.8%, Ti: 2.4-2.8%, Mg: ≤0.03%, B: ≤0.01%, La: ≤0.1%, Ce: ≤0.01%, and the balance being Ni and inevitable impurities; The preparation method comprises the following steps: Step A, the alloy is prepared according to the above element component ratio, and is homogenized by vacuum induction furnace melting, the melting temperature is 1440℃, and the molten steel is prepared; Step B, the molten steel of step A is heated to 1410℃ for refining, continues to deoxidize and degas, volatilizes harmful impurity elements, adjusts the content of alloy elements, homogenizes, and reduces composition segregation; the refining time is determined according to the change of air leakage rate, aluminum and titanium are added during the later stage of refining, sampling analysis is carried out during the period, the composition is adjusted, and high-quality molten steel is prepared; Step C, the high-quality molten steel of step B is poured into an electrode rod under vacuum conditions, 10 kg of Ni-Mg, 0.69 kg of La and 0.69 kg of Ce are added before tapping; Step D, the electrode rod of step C is used as an electrode, and after turning, it is placed in a vacuum consumable furnace for secondary remelting and purification to form a consumable ingot; Step E, the consumable ingot prepared in step D is heated to 1170℃ and homogenized for 42 h; Step F, the steel ingot of step E is heated to 1150℃, and after holding for 4 h, it is taken out of the package and is recycled for 2 h, and then is rapidly forged into a material by using a press through two upsetting and two drawing, and is air-cooled, and the high-temperature alloy turbine disc material is obtained.

[0008] The high-temperature alloy material for turbine disc prepared by the method has good uniformity, and the high-temperature stress rupture property and grain size of the obtained sealing plate material are improved by controlling the method. The pure and uniform steel ingot is obtained by vacuum induction furnace smelting and vacuum consumable remelting, and the round steel material with uniform structure is prepared after heat treatment by optimizing the heating system, forging process, forging heating temperature, heat preservation measures in the forging process, the grain size difference of the cross section and longitudinal surface of the round steel is not more than 1.0 level, the average grain size reaches 3.0 level, and the round steel has good transverse mechanical properties and high-temperature stress rupture properties. The high-temperature alloy material produced by the method has a stress rupture time of more than 170 h and a tensile strength at room temperature of more than 1400 Mpa, and can well meet the performance requirements of the high-temperature alloy for turbine disc.

[0009] In the method, before tapping, 10 kg of Ni-Mg, 0.69 kg of La and 0.69 kg of Ce and other trace elements are added before tapping in step C, so that the high-temperature creep property of the material is improved, the grain boundary is strengthened, and the plasticity and yield strength of the turbine disc material are enhanced at low temperature, room temperature and high temperature.

[0010] Further, in step A, the molten steel is smelted in a 6T vacuum induction furnace.

[0011] Further, in step B, the refining time of the vacuum induction furnace is determined according to the air leakage rate.

[0012] Further, in step B, the 6T vacuum induction furnace is refined.

[0013] Further, in step C, the weight ratio of Ni to Mg in the Ni-Mg alloy is 4:1.

[0014] Further, in step E, the homogenization treatment is carried out in a high-temperature furnace, first at 1120 DEG C for 12 h, then at 1135 DEG C for 16 h, and finally at 1170 DEG C for 42 h.

[0015] Further, in step F, under the condition of cooling forging, baking and package heat preservation, the key heating time is 1120 DEG C package baking rapid forging.

[0016] The second object of the present application is to provide a high-temperature alloy turbine disc material prepared by the method as described above, which comprises the following element components in percentage by weight: C: ≤0.08%, Cr: 13.0-15.0%, Co: 9.0-11.0%, Mo: 4.5-5.5%, Fe: ≤0.5%, Nb: 2.4-2.8%, Al: 2.4-2.8%, Ti: 2.4-2.8%, Mg: ≤0.03%, B: ≤0.01%, La: ≤0.1%, Ce: ≤0.01%, the balance being Ni and inevitable impurities.

[0017] Further, the impurities are: S ≤0.001%, P ≤0.005% in percentage by weight, wherein the content of S is controlled to be ≤10 ppm and the content of P is controlled to be ≤50 ppm during the preparation process.

[0018] The beneficial effects of the present application are as follows: (1) The high-temperature alloy material produced by the present application has a long-term rupture time of greater than 170 h, a tensile strength at room temperature of greater than 1400 Mpa, and an elongation at long-term rupture of greater than 5%. The performance requirements of the high-temperature alloy for turbine disc are met, the material has excellent high-temperature creep performance, and has good economic and social benefits, and is suitable for popularization and use. (2) The high-temperature alloy sealing plate material provided by the present application has a uniform structure, and the smelting and pouring are carried out in a vacuum environment. Before tapping, 10 kg of Ni-Mg (4:1, w:w), 0.69 kg of La and 0.69 kg of Ce and other trace elements are added to improve the high-temperature creep performance of the material, strengthen the grain boundary, and enhance the plasticity and yield strength of the turbine disc material at low temperature, room temperature and high temperature. A 6000T press is used for forging, and two upsetting and two drawing, cooling forging, key heating at 1120℃, baking and rapid forging are carried out, and the forged material is slowly cooled to room temperature. The alloy has a uniform structure, and the grain size difference of the cross section and the longitudinal cross section of the round steel is not more than 1.0 grade, and the average grain size reaches 3.0 grade. DETAILED DESCRIPTION

[0019] In order to make the objects, technical solutions and advantages of the present application clearer, the present application is specifically described below in conjunction with examples. It should be noted that the following examples are only used to explain and illustrate the present application, and do not limit the present application. Some non-essential improvements and adjustments made by those skilled in the art based on the above description still fall within the scope of the present application. EXAMPLE

[0020] A high-temperature alloy material for a turbine disc, consisting of the following element components in percentage by weight: C: 0.08%, Cr: 13.0%, Co: 9.0%, Mo: 4.5%, Fe: 0.5%, Nb: 2.4%, Al: 2.4%, Ti: 2.4%, Mg: 0.03%, B: 0.01%, La: 0.1%, Ce: 0.01%, S: 0.001%, P: 0.005%, and the balance being Ni.

[0021] The preparation method comprises the following steps: Step A, the alloy is prepared according to the element component ratio, and is homogenized by 6T vacuum induction furnace melting at a melting temperature of 1440℃ to form molten steel; Step B, the molten steel of step A is heated to 1410℃ and refined in the 6T vacuum induction furnace, and continues to deoxidize and degas, volatilize harmful impurity elements, adjust the content of alloy elements, homogenize, and reduce composition segregation; the refining time is determined according to the change of air leakage rate, aluminum and titanium are added after power-off cooling at the later stage of refining, sampling analysis is performed during the period, the composition is adjusted, and high-quality molten steel is prepared; Step C, the high-quality molten steel of step B is poured into an electrode rod under vacuum conditions, and 10 kg of Ni-Mg (Ni:Mg=4:1, w:w), 0.69 kg of La and 0.69 kg of Ce are added before tapping; Step D, the electrode rod of step C is taken as an electrode, and after bright turning, is placed in a vacuum consumable furnace for secondary remelting and purification to form a consumable ingot; Step E, the consumable ingot prepared in step D is first kept at 1120℃ for 12 h, then heated to 1135℃ and kept for 16 h, and finally heated to 1170℃ and kept for 42 h for homogenization treatment; Step F, the steel ingot of step E is heated to 1150℃, kept for 4 h, then taken out of the ladle, and after being recycled and kept for 2 h, is forged into a material by two upsetting and two drawing through a press under the measures of cooling, heating and ladling, and is air-cooled at 1120℃ in the key heating time to obtain the material. Embodiment

[0022] A high-temperature alloy material for a turbine disc, consisting of the following element components in percentage by weight: C: 0.04%, Cr: 15.0%, Co: 11.0%, Mo: 5.5%, Fe: 0.42%, Nb: 2.8%, Al: 2.8%, Ti: 2.8%, Mg: 0.02%, B: 0.005%, La: 0.08%, Ce: 0.006%, S: 0.0005%, P: 0.003%, and the balance being Ni.

[0023] The preparation method comprises the following steps: Step A, the alloy is prepared according to the above element composition and proportion, and is homogenized by melting in a 6T vacuum induction furnace at a melting temperature of 1440℃ to form molten steel; Step B, the molten steel of step A is heated to 1410℃ in a 6T vacuum induction furnace for refining, and continues to be deoxidized and degassed to volatilize harmful impurity elements, adjust the content of alloy elements, homogenize, and reduce composition segregation; the refining time is determined according to the change of air leakage rate, aluminum and titanium are added during the late stage of refining after power-off cooling, sampling analysis is performed during the period, the composition is adjusted, and high-quality molten steel is prepared; Step C, the high-quality molten steel of step B is poured into an electrode rod under vacuum conditions before tapping, 10 kg of Ni-Mg (Ni:Mg=4:1, w:w), 0.69 kg of La and 0.69 kg of Ce are added; Step D, the electrode rod of step C is used as an electrode, and after turning, it is placed in a vacuum consumable furnace for secondary remelting and purification to form a consumable ingot; Step E, the consumable ingot prepared in step D is first heat treated at 1120℃ for 12 h, then heated to 1135℃ and held for 16 h, and finally heated to 1170℃ and held for 42 h for homogenization treatment; Step F, the steel ingot of step E is heated to 1150℃, held for 4 h, then taken out of the package, and recycled for 2 h, then subjected to two upsetting and two drawing by a press, and subjected to cooling, heating and package measures, and finally forged into a material at a critical heating time of 1120℃, and air cooled to obtain the material. Embodiment

[0024] A high-temperature alloy material for a turbine disc, consisting of the following element components in percentage by weight: C: 0.02%, Cr: 14.10%, Co: 10.3%, Mo: 5.1%, Fe: 0.4%, Nb: 2.6%, Al: 2.5%, Ti: 2.6%, Mg: 0.025%, B: 0.006%, La: 0.07%, Ce: 0.009%, S: 0.0008%, P: 0.003%, and the balance being Ni.

[0025] The preparation method comprises the following steps: Step A, the alloy is prepared according to the above element composition and proportion, and is homogenized by melting in a 6T vacuum induction furnace at a melting temperature of 1440℃ to form molten steel; Step B, the molten steel of step A is heated to 1410℃ in a 6T vacuum induction furnace for refining, and continues to be deoxidized and degassed to volatilize harmful impurity elements, adjust the content of alloy elements, homogenize, and reduce composition segregation; the refining time is determined according to the change of air leakage rate, aluminum and titanium are added during the late stage of refining after power-off cooling, sampling analysis is performed during the period, the composition is adjusted, and high-quality molten steel is prepared; Step C, the high-quality molten steel of step B is cast into electrode rods under vacuum, 10 kg of Ni-Mg (Ni:Mg=4:1, w:w), 0.69 kg of La and 0.69 kg of Ce are added before tapping; Step D, the electrode rods of step C are taken as electrodes and placed in a vacuum consumable furnace after machining to perform secondary remelting purification, forming a consumable ingot; Step E, the consumable ingot prepared in step D is subjected to homogenization treatment, first at 1120℃ for 12 h, then at 1135℃ for 16 h, and finally at 1170℃ for 42 h; Step F, the ingot of step E is heated to 1150℃, held for 4 h, then taken out of the ladle, and recycled for 2 h, then subjected to two upsetting and two drawing by a press, and subjected to cooling, heating, and ladling measures, and forged into a material at 1120℃, and air-cooled.

[0026] Test Example The high-temperature alloy round steel material prepared by the method of embodiments 1-3 is subjected to performance testing, the testing method is in accordance with the current standard and general method, and the results are as shown in Table 1. As can be seen from Table 1, the high-temperature alloy material prepared by the method of the present application has uniform alloy structure, the grain size difference of the cross section and longitudinal cross section of the round steel is not more than 1.0 grade, the average grain size reaches 3.0 grade, and the high-temperature durability and room temperature tensile strength are extremely excellent.

[0027]

Claims

1. A method of producing a high temperature alloy material for a turbine disk, characterized by, The high-temperature alloy material comprises the following element components in percentage by weight: C: ≤0.08%, Cr: 13.0-15.0%, Co: 9.0-11.0%, Mo: 4.5-5.5%, Fe: ≤0.5%, Nb: 2.4-2.8%, Al: 2.4-2.8%, Ti: 2.4-2.8%, Mg: ≤0.03%, B: ≤0.01%, La: ≤0.1%, Ce: ≤0.01%, the balance being Ni and inevitable impurities. The preparation method comprises the following steps: Step A, the alloy is prepared according to the element component ratio, and is homogenized by vacuum induction furnace melting, the melting temperature is 1440℃, and the molten steel is prepared; Step B, the molten steel of step A is heated to 1410℃ for refining, continues to deoxidize and degas, volatilizes harmful impurity elements, adjusts the content of alloy elements, homogenizes, and reduces composition segregation; the refining time is determined according to the change of the air leakage rate, aluminum and titanium are added in the later stage of refining after power-off cooling, sampling analysis is performed during the period, the composition is adjusted, and high-quality molten steel is prepared; Step C, the high-quality molten steel of step B is poured into an electrode rod under vacuum conditions, 10 kg of Ni-Mg, 0.69 kg of La and 0.69 kg of Ce are added before tapping; Step D, the electrode rod of step C is used as an electrode, and after bright turning, it is placed in a vacuum consumable furnace for secondary remelting and purification to form a consumable ingot; Step E, the consumable ingot prepared in step D is heated to 1170℃ and homogenized for 42 hours; Step F, the steel ingot of step E is heated to 1150℃, and after holding for 4 hours, it is taken out of the package and is recycled for 2 hours, then is forged into a material by two upsetting and two drawing through a press, and is air-cooled.

2. The method of claim 1, wherein: In step A, the molten steel is melted in a 6T vacuum induction furnace.

3. The production method according to claim 1 or 2, characterized by: In step B, the refining is performed in a 6T vacuum induction furnace.

4. The production method according to claim 1 or 2, characterized by: In step C, the weight ratio of Ni to Mg in the Ni-Mg alloy is 4:

1.

5. The production method according to claim 1 or 2, characterized by: In step E, the homogenization treatment is performed in a high-temperature furnace, first holding at 1120℃ for 12 hours, then heating to 1135℃ and holding for 16 hours, and finally heating to 1170℃ and holding for 42 hours.

6. The production method according to claim 1 or 2, characterized by: In step F, the key heating time for forging into a material is 1120℃ package heating for rapid forging.

7. The production method according to claim 1 or 2, characterized by: The content of S is controlled to be ≤10ppm and the content of P is controlled to be ≤50ppm during the whole preparation process.

8. The high temperature alloy material for turbine disks produced by the method according to any one of claims 1 to 7, characterized by: The high-temperature alloy material comprises the following element components in percentage by weight: C: ≤0.08%, Cr: 13.0-15.0%, Co: 9.0-11.0%, Mo: 4.5-5.5%, Fe: ≤0.5%, Nb: 2.4-2.8%, Al: 2.4-2.8%, Ti: 2.4-2.8%, Mg: ≤0.03%, B: ≤0.01%, La: ≤0.1%, Ce: ≤0.01%, the balance being Ni and inevitable impurities.

9. The high temperature alloy material for a turbine disk according to claim 8, characterized by: The impurities are S ≤0.001% and P ≤0.005% in percentage by weight.

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