CN115283629A - Method for preparing nickel-based high-temperature alloy by using double-roller casting and rolling process - Google Patents

Abstract

The invention proposes a method for preparing nickel-based superalloy by using a twin-roll casting and rolling process, which realizes the application of the twin-roll casting and rolling process in the field of nickel-based superalloy, has few preparation processes, and is beneficial to the industrial-scale production of nickel-based superalloy. It is not only suitable for GH4049 alloy and GH4169 alloy, but also for the production of other nickel-based superalloys; using the combination of vacuum melting furnace, vacuum protective cover and dry ice cooling, there is no need to put cooling components, shearing components, etc. into the vacuum protective cover. While realizing the cooling of the nickel-based superalloy, the number of components that need to be put into the vacuum protection cover can be reduced, and the difficulty and cost of producing the nickel-based superalloy with high product quality are reduced.

Description

A method for preparing nickel-based superalloys by twin-roll casting and rolling process

technical field

The invention relates to the technical field of metal casting, in particular to a method for preparing a nickel-based superalloy by using a twin-roll casting and rolling process.

Background technique

Nickel-based superalloys are superalloys with nickel as the matrix (generally more than 50%) in the range of 650-1000 °C with high strength and good oxidation resistance and gas corrosion resistance. Nickel-based superalloys play an important role in the field of superalloys, and are widely used in the manufacture of aviation jet engines and the hottest parts of various industrial gas turbines. Turbine blades are mainly made of nickel-based high-temperature alloys, and their working environment is the worst in the entire engine, under the conditions of high temperature, high pressure and high-speed rotation. Compared with iron-based superalloys, nickel-based superalloys have the advantages of higher working temperature, stable structure, less harmful phases and strong oxidation and corrosion resistance.

The traditional production of nickel-based superalloys is to mold the metal, and then process the ingot by forging, hot rolling, welding, cold rolling, etc. This production process requires large investment in equipment, many processes, and poor surface quality. Many cracks, low yield, and low production efficiency. In order to improve production quality and reduce production cost, it is urgent to develop a nickel-based superalloy production process with low production cost and high product quality.

The twin-roll casting and rolling process is to directly make the metal melt into semi-finished products or finished billets. The remarkable feature of this process is that the crystallizer is two rotary casting rolls with water cooling system, and the melt undergoes a series of processes such as pouring, cooling, crystallization, solidification, rolling and billeting under the action of roll cooling and extrusion. , and finally obtain the required plate, which has the advantages of simple production process, short production cycle, high efficiency and low energy consumption.

Chinese patent (CN 109822067A) uses the twin-roll method to continuously prepare thin strips of nickel-based amorphous alloys, using common industrial raw materials, and based on the thin strip casting and rolling process, it can provide a continuous and stable solidification environment. The amorphous formation process is short and The cooling speed is fast and the preparation process is continuous.

However, due to the high quality and performance requirements of the working environment of nickel-based superalloys, the existing preparation methods cannot meet the needs of industrial production, and although the casting and rolling process has many advantages, it still requires a lot of There are no reports about the process of producing nickel-based superalloys by casting and rolling process in the prior art.

Contents of the invention

In order to solve the above-mentioned technical problems, the present invention proposes a method for preparing a nickel-based superalloy using a twin-roll casting and rolling process. The twin-roll casting and rolling process is used to realize the preparation of a high-quality nickel-based superalloy, with high production efficiency and low production cost.

According to one aspect of the present invention, the present invention provides following technical scheme:

A method for preparing a nickel-based superalloy by twin-roll casting and rolling process, comprising the steps of:

S1. Put the crucible in the vacuum melting furnace, put the nickel-based superalloy raw material into the crucible for melting, and keep it warm for a period of time to ensure that the raw material is completely melted;

S2. Place the tundish and casting-rolling unit in a vacuum protection cover, and place the cooling components and shearing components outside the vacuum protection cover; pour the completely melted alloy liquid into the baked tundish and let it stand for a period of time , the tundish is equipped with a heating device to heat and keep the alloy liquid in the tundish;

S3. When the temperature of the alloy liquid meets the casting temperature requirement, the alloy liquid is cast into the water-cooled rolls of the two-roll casting and rolling unit to realize the casting and rolling forming of the superalloy;

S4. Use dry ice to cool the products cast and rolled by the twin-roll casting and rolling unit, and control the cooling rate to 600-900°C/s;

S5. Cutting, finished product.

As a preferred scheme of the method for preparing a nickel-based superalloy by a twin-roll casting process in the present invention, wherein: in the step S1, the melting temperature is the melting point of the alloy + (150-250) °C, and the holding time is 5- 10 minutes; specifically, the melting temperature is, for example but not limited to, alloy melting point +150°C, alloy melting point +160°C, alloy melting point +170°C, alloy melting point +180°C, alloy melting point +190°C, alloy melting point +200°C, Any one of alloy melting point +210°C, alloy melting point +220°C, alloy melting point +230°C, alloy melting point +240°C, alloy melting point +250°C or any two of them; the holding time is 5 minutes, Any one of 6min, 7min, 8min, 9min, 10min or the range between any two; the setting of melting temperature and holding time ensures the full melting of nickel-based superalloy;

As a preferred solution of the method for preparing nickel-based superalloys by twin-roll casting and rolling process in the present invention, wherein: in the step S1, the vacuum degree of the vacuum melting furnace is kept below 10 ^-1 Pa, and the Check the vacuum once.

As a preferred solution of the method for preparing nickel-based superalloys by twin-roll casting and rolling process according to the present invention, wherein: in the step S2, the vacuum degree of the vacuum protection cover is kept below 10 ^-1 Pa, Check the vacuum once. Through the control and periodic detection of the vacuum degree, the protection of the production process of the nickel-based superalloy is realized.

As a preferred solution of the method for preparing nickel-based superalloys using a twin-roll casting process in the present invention, wherein: in the step S2, the tundish heating device is an electric heating wire embedded in the tundish refractory material, statically The setting time is 60-120s. The standing time is, for example but not limited to, any one of 60s, 70s, 80s, 90s, 100s, 110s, 120s or a range between any two; Standing for a period of time is conducive to the uniform temperature of the alloy liquid. If the standing time is too long, the temperature of the alloy liquid will drop, which will waste energy and reduce production efficiency. At the same time, the electric heating wire embedded in the refractory material of the tundish is used to heat the alloy liquid. , While providing heat, it does not pollute the alloy liquid.

As a preferred scheme of the method for preparing nickel-based superalloys by twin-roll casting and rolling process according to the present invention, wherein: in the step S3, the temperature of the alloy liquid to meet the casting temperature requirement means that the temperature of the alloy liquid is Melting point + (150-200) ° C; specifically, the temperature of the alloy liquid is, for example but not limited to, alloy melting point + 150 ° C, alloy melting point + 160 ° C, alloy melting point + 170 ° C, alloy melting point + 180 ° C, alloy melting point + 190 ℃, alloy melting point + 200 ℃, or any range between the two; the setting of the alloy liquid temperature ensures the smooth progress of the casting and rolling process.

As a preferred solution of the method for preparing nickel-based superalloys by twin-roll casting and rolling process according to the present invention, wherein: in the step S3, the shape of the water-cooled roll can be adjusted according to the product, parameters such as rolling pressure and casting speed It can also be adjusted according to the product.

As a preferred solution of the method for preparing nickel-based superalloys using a twin-roll casting process in the present invention, wherein: in the step S4, the cooling rate is controlled to be 700-900°C/s; preferably, the cooling rate is controlled It is 700-800°C/s; the applicant found that too small cooling rate (<600°C/s) will not be able to meet the cooling and forming needs of nickel-based superalloy products, and too large cooling rate (>900°C/s ) will cause some dry ice to be unable to participate in the cooling process, and the effective utilization of dry ice cannot be realized, resulting in waste of dry ice; specifically, the cooling rate is, for example but not limited to, 700°C/s, 710°C/s, 720°C/s Any one of s, 730°C/s, 740°C/s, 750°C/s, 760°C/s, 770°C/s, 780°C/s, 790°C/s, 800°C/s or both The range between; using dry ice for cooling, directly spraying dry ice on the surface of nickel-based superalloy materials, not only can quickly reduce the temperature of nickel-based superalloy products, but also spraying solid dry ice on the surface of nickel-based superalloy materials in a hot state will cause Gasification, forming a CO ₂ gas protective atmosphere on the surface of the nickel-based superalloy material, which acts as an anti-oxidant, so that there is no need to put cooling components, shearing components, etc. into the vacuum protection cover; while realizing the cooling of the nickel-based superalloy material Reducing the number of components that need to be placed in a vacuum shield reduces production costs. However, the existing superalloy twin-roll casting and rolling process needs to put the tundish, casting and rolling unit, cooling components, shearing components, etc. into the vacuum protection cover. First, the volume of the vacuum protective cover that needs to be prepared is huge, which increases the production cost; second, because the components are all located in the vacuum protective cover, it makes it difficult to operate individual processes, which is not convenient for industrial production and hinders technological progress.

According to another aspect of the present invention, the present invention provides the following technical solutions:

A nickel-based high-temperature alloy is prepared by adopting the method for preparing nickel-based high-temperature alloy by using the above-mentioned twin-roll casting and rolling process.

As a preferred solution of a nickel-based superalloy in the present invention, the nickel-based superalloy includes but not limited to GH4049 alloy and GH4169 alloy.

The beneficial effects of the present invention are as follows:

The present invention proposes a method for preparing nickel-based superalloys using a twin-roll casting process, which realizes the application of the twin-roll casting process in the field of nickel-based superalloys, has fewer preparation processes, and is conducive to the industrial scale production of nickel-based superalloys. It is not only suitable for GH4049 alloy and GH4169 alloy, but also suitable for the production of other nickel-based superalloys; it adopts the combination of vacuum melting furnace, vacuum protective cover and dry ice cooling, and does not need to put cooling components, shear components, etc. into the vacuum protective cover. Realizing the cooling of the nickel-based superalloy can reduce the number of components that need to be placed in the vacuum protection cover, and reduce the difficulty and cost of production and operation of the high-quality nickel-based superalloy.

Detailed ways

A clear and complete description will be made below in conjunction with the technical solutions in the embodiments. Apparently, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

The present invention proposes a method for preparing nickel-based superalloys using a twin-roll casting and rolling process, using a combination of a vacuum melting furnace, a vacuum protective cover and dry ice cooling, without putting cooling components, shearing components, etc. into the vacuum protective cover, and realizing While cooling the nickel-based superalloy, it can reduce the number of components that need to be placed in the vacuum protection cover, reducing the difficulty and cost of producing high-quality nickel-based superalloys; realizing the application of twin-roll casting and rolling technology in the field of nickel-based superalloys , the preparation process is less, which is conducive to the industrial scale production of nickel-based superalloys, not only suitable for GH4049 alloy and GH4169 alloy, but also suitable for the production of other nickel-based superalloys.

In the following, GH4049 alloy and GH4169 alloy are taken as examples for specific description.

Example 1

A preparation method of GH4049 alloy, comprising the steps of:

S1. Put the crucible in the vacuum melting furnace, put the GH4049 alloy raw material into the crucible, heat up to 1560°C for melting, and keep it warm for 8 minutes to ensure that the raw material is completely melted;

S2. Put the tundish and casting-rolling unit in the vacuum protection cover, vacuumize the vacuum protection cover, keep the vacuum degree below 10 ^-1 Pa, pour the completely melted GH4049 alloy liquid into the baked middle In the tundish, stand still for 90s, and at the same time use the tundish heating device to heat and keep the GH4049 alloy liquid in the tundish;

S3. When the temperature of the alloy liquid reaches 1520°C and the standing time meets the requirements, the alloy liquid is cast into the water-cooled rolls of the two-roll casting and rolling unit to realize the casting and rolling forming of the superalloy;

S4. Use dry ice to cool the products cast and rolled by the twin-roll casting and rolling unit, and control the cooling rate to 760°C/s;

S5. Shearing to prepare a GH4049 alloy strip with a thickness of 1.2 mm.

Comparative example 1.1

The difference between Comparative Example 1.1 and Example 1 is that step S4 uses water cooling.

Comparative example 1.2

The difference between Comparative Example 1.2 and Example 1 is that the alloy liquid is cast into the water-cooled rolls of the casting-rolling unit when the temperature of the alloy liquid is 1450°C.

Example 2

A preparation method of GH4169 alloy, comprising the steps of:

S1. Put the crucible in the vacuum melting furnace, put the GH4169 alloy raw material into the crucible, heat up to 1500°C for melting, and keep it warm for 5 minutes to ensure that the raw material is completely melted;

S2. Put the tundish and casting-rolling unit in the vacuum protection cover, vacuumize the vacuum protection cover, keep the vacuum degree below 10 ^-1 Pa, pour the completely melted GH4169 alloy liquid into the baked middle In the tundish, stand still for 120s, and at the same time use the tundish heating device to heat and keep the GH4169 alloy liquid in the tundish;

S3. When the temperature of the alloy liquid reaches 1500°C and the standing time meets the requirements, the alloy liquid is cast into the water-cooled rolls of the two-roll casting and rolling unit to realize the casting and rolling forming of the superalloy;

S4. Use dry ice to cool the cast-rolled products of the twin-roll cast-rolling unit, and control the cooling rate of the GH4169 alloy material to 730°C/s;

S5. Shearing to prepare a GH4169 alloy strip with a thickness of 0.8 mm.

Comparative example 2.1

The difference between Comparative Example 2.1 and Example 2 is that step S4 uses water cooling.

Comparative example 2.2

The difference between Comparative Example 2.2 and Example 2 is that the alloy liquid is cast into the water-cooled rolls of the casting-rolling unit when the temperature of the alloy liquid is 1370°C.

The nickel-based superalloy materials prepared by using Examples 1-2 and Comparative Examples 1.1-1.2 and 2.1-2.2 were tested, analyzed and detected, and the results are shown in Table 1.

Table 1 Ni-based superalloy properties prepared by the embodiments of the present invention and comparative examples

Alloy liquid casting temperature/℃ cooling medium Defect situation coagulated tissue Example 1 1520 dry ice Well formed surface with no defects tissue distribution Comparative example 1.1 1520 water Defects such as pits on the surface uneven tissue distribution Comparative example 1.2 1450 dry ice No surface defects uneven tissue distribution Example 2 1500 dry ice Well formed surface with no defects tissue distribution Comparative example 2.1 1500 water Defects such as pits on the surface uneven tissue distribution Comparative example 2.2 1370 dry ice No surface defects uneven tissue distribution

As can be seen from Table 1: using dry ice for cooling and casting within the alloy liquid temperature range limited by the present invention, the nickel-based superalloy material prepared with twin-roll casting and rolling process and its parameters has good surface forming, no defects, and microstructure distribution Uniform, meeting the basic quality requirements for nickel-based superalloy materials.

If dry ice cooling is not used in the cooling stage, the surface of the nickel-based superalloy will be oxidized, resulting in defects such as pits on the surface (such as Comparative Examples 1.1 and 2.1). At the same time, due to the mismatch between the casting temperature and the cooling rate, nickel The solidification speed of different parts of the base superalloy varies greatly, resulting in uneven distribution of solidified structures (such as Comparative Examples 1.2 and 2.2), which cannot meet the basic quality requirements of nickel-based superalloys.

The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. Under the inventive concept of the present invention, the equivalent structural transformation made by using the content of the description of the present invention, or directly/indirectly used in other related All technical fields are included in the patent protection scope of the present invention.

Claims (10)

1. A method for preparing nickel-base superalloy by twin-roll casting and rolling technique, is characterized in that, comprises the steps: S1. Put the crucible in the vacuum melting furnace, put the nickel-based superalloy raw material into the crucible for melting, and keep it warm for a period of time to ensure that the raw material is completely melted; S2. Place the tundish and casting-rolling unit in a vacuum protection cover, and place the cooling components and shearing components outside the vacuum protection cover; pour the completely melted alloy liquid into the baked tundish and let it stand for a period of time , the tundish is equipped with a heating device to heat and keep the alloy liquid in the tundish; S3. When the temperature of the alloy liquid meets the casting temperature requirement, the alloy liquid is cast into the water-cooled rolls of the two-roll casting and rolling unit to realize the casting and rolling forming of the superalloy; S4. Use dry ice to cool the products cast and rolled by the twin-roll casting and rolling unit, and control the cooling rate to 600-900°C/s; S5. Cutting, finished product. 2. A method for preparing nickel-based superalloys by twin-roll casting and rolling process according to claim 1, characterized in that, in the step S1, the melting temperature is the melting point of the alloy + (150-250) °C, and the holding time is 5-10min. 3. A method for preparing nickel-based superalloys by twin-roll casting and rolling process according to claim 1, characterized in that, in the step S1, the vacuum degree of the vacuum melting furnace is kept below 10 ^-1 Pa, every 20-40s to check the vacuum once. 4. A method for preparing nickel-based superalloys by twin-roll casting and rolling process according to claim 1, characterized in that, in the step S2, the vacuum degree of the vacuum protection cover is kept below 10 ^-1 Pa, every 20-40s to check the vacuum once. 5. A method for preparing nickel-based superalloys by twin-roll casting and rolling process according to claim 1, characterized in that, in the step S2, the tundish heating device is an electric heating wire embedded in the tundish refractory material , the standing time is 60-120s. 6. A method for preparing nickel-based superalloys by twin-roll casting and rolling process according to claim 1, characterized in that, in the step S3, the temperature of the alloy liquid to meet the casting temperature requirement refers to the temperature of the alloy liquid It is the alloy melting point + (150-200) °C. 7. A method for preparing a nickel-based superalloy by twin-roll casting and rolling process according to claim 1, characterized in that, in the step S4, the cooling rate is controlled to be 700-900°C/s. 8. A method for preparing a nickel-based superalloy by twin-roll casting and rolling process according to claim 1, characterized in that, in the step S4, the cooling rate is controlled to be 700-800°C/s. 9. A nickel-based superalloy, prepared by the method for preparing a nickel-based superalloy by using a twin-roll casting and rolling process according to any one of claims 1-8. 10. A nickel-based superalloy according to claim 9, characterized in that the nickel-based superalloy is GH4049 alloy or GH4169 alloy.