Preparation method for effectively improving easily-mixed or coarse-grain high-temperature alloy ring forgings with different sizes

Abstract

The invention provides a preparation method for effectively improving easily-mixed or coarse-grain high-temperature alloy ring forgings with different sizes, the size of the ring forgings is judged according to the outer diameter, and then preparation is completed according to the ring forgings preparation method. After the forging and chambering processes of the large-size ring forge piece are completed, the deformation in the finish rolling process is not less than 25%; after the forging and broaching processes of the small-size ring forging are completed, the deformation in the finish rolling process is smaller than 25%, and after the finish rolling process is completed, the obtained ring forging is returned to a furnace and subjected to heat preservation at 1050 DEG C for at least 15 min. According to the method, the ring forgings are distinguished according to the outer diameter, the deformation of the large-size ring forgings in the finish rolling stage is controlled to be not smaller than 25%, and internal crystal grains are dynamically recrystallized under the action of high-temperature large deformation, so that the internal crystal grains are refined; the deformation amount of the small-size ring forge piece is controlled to be not larger than 25% in the ring rolling process, a hot material remelting mode is combined, and quasi-dynamic recrystallization occurs in the forge piece after hot material remelting, so that the effect of refining internal crystal grains is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of metal processing, in particular to a method for preparing forgings of easily miscible or coarse-grained high-temperature alloy rings of different sizes. Background Art

[0002] High-temperature alloys are widely used in the aerospace field, especially in high-temperature and high-pressure working environments such as aircraft engines, gas turbines, and aircraft generators. With the rapid development of the current aerospace industry, the demand for high-temperature alloy materials is also increasing; in the fields of electricity and nuclear energy, the demand for high-temperature alloy parts for gas turbines and nuclear power plant equipment is also expanding. With the adjustment of the global energy structure and the upgrading of advanced manufacturing industries, the market demand for high-temperature alloys has increased rapidly. With the global transition to a green and low-carbon economy, the demand for new materials that are resistant to high temperatures, environmentally friendly, and energy-saving has surged, and high-temperature alloys have become the core material to meet this trend; as for other fields, high-temperature alloys also have broad application prospects in petrochemicals, automobile manufacturing, medical devices and other fields. With the advancement of science and technology and the development of emerging fields, the scope of high-temperature alloys will be further broadened.

[0003] Based on the current broad use and future prospects of high-temperature alloys, the requirements for high-temperature alloys are becoming more and more stringent. However, current high-temperature alloys (GH141, GH738, GH4080A, etc.) have the phenomenon of easy mixing / coarse grains. Based on the above situation, the present invention provides a preparation method for high-temperature alloy ring forgings with effective improvement of easy mixing or coarse grains for different sizes, aiming to meet the requirements of effectively improving the grain mixing / coarse grain situation by regulating parameters such as forging temperature, deformation amount, and whether to return hot materials to the furnace for different sizes.

[0004] The current existing technologies for solving the coarse grain and mixed grain problems of high temperature alloys mainly adopt the following treatment methods:

[0005] 1. Strictly control the heating temperature and holding time of high-temperature alloys to obtain ideal grain size. The selection of heating temperature should take into account the chemical composition and phase transition point of the alloy to avoid excessively high or low temperatures that lead to abnormal grain growth or insufficient grain refinement;

[0006] 2. Ensure a sufficient forging ratio. Usually, a forging ratio between 4 and 6 is more appropriate to obtain uniform and fine grains. The number and amount of deformation should be controlled during the forging process to avoid grain coarsening caused by too many fires and insufficient deformation. Specific forging processes can also be used during forging, such as upsetting + drawing + special-shaped anvil drawing, etc., to improve the uniformity of grain size;

[0007] 3. Through heat treatment, a uniform supersaturated solid solution can be obtained and the appropriate grain size can be controlled. The selection of heat treatment temperature and time should be determined according to the specific composition and performance requirements of the alloy. The cooling rate will also affect the grain size after heat treatment, so the cooling rate should be reasonably controlled to obtain the ideal grain structure.

[0008] In order to meet the performance requirements in the actual production process, the heat treatment system is usually a fixed mode, and it is difficult to effectively improve the grain size through heat treatment. Therefore, from the heat treatment process forward, only by effectively controlling the grain size of the forgings before heat treatment and during the forging process can it be guaranteed that the grain size of the forgings will not be mixed or coarse. For large-sized high-temperature alloys, the grain size of the forgings can be effectively improved through large deformation, but for small-sized high-temperature alloy forgings that cannot be greatly deformed, the grain size of the forgings cannot be effectively controlled in actual production. Therefore, the single control of forging temperature and deformation cannot be applied to high-temperature alloy forgings of different sizes, resulting in the inability to effectively recrystallize the grain size during the forging production process. Summary of the invention

[0009] The technical problem to be solved by the present invention is to overcome the defects of the prior art. The present invention proposes a preparation method for high-temperature alloy ring forgings of different sizes with effective improvement of easy mixing or coarse grains. For GH4080A high-temperature alloy ring forgings of different sizes, by adjusting the forging temperature, deformation amount and whether the hot material is returned to the furnace, the grain size of the ring forging undergoes effective recrystallization or quasi-dynamic recrystallization, effectively improving the easy mixing / coarse grain situation of the high-temperature alloy ring forgings.

[0010] In order to solve the above technical problems, the technical solution adopted by the present invention is: effectively improving the preparation method of easily miscible or coarse-grained high-temperature alloy ring forgings of different sizes, judging the size of the ring forgings according to the outer diameter, and then completing the preparation process of the ring forgings according to the preparation method of the ring forgings of the corresponding size;

[0011] The ring forgings include large-size ring forgings and small-size ring forgings, wherein the outer diameter of the large-size ring forgings is greater than 1.5 m, and the outer diameter of the small-size ring forgings is not greater than 1.5 m;

[0012] After the large-size ring forging is completed through forging and hole expansion, during the ring rolling process, the deformation amount of the final rolling process is not less than 25%, preferably 25-30%;

[0013] After the small-size ring forging is completed with the forging and hole expansion process, during the ring rolling process, the deformation of the final rolling process is less than 25%, preferably less than 20%, and after the final rolling process is completed, the obtained ring forging is returned to the furnace and kept warm at 1050° C. for at least 15 minutes.

[0014] Furthermore, the relationship between the holding time of the small-sized ring forging and the effective wall thickness of the ring forging is as follows:

[0015]

[0016] Where T is the holding time in min, and x is the effective wall thickness of the ring forging in mm.

[0017] Furthermore, after the small-sized ring forgings complete the horse frame expansion process, they are loaded into a furnace at an environment not higher than 1040°C, heated to 1080-1100°C, kept warm for 235-385 minutes, and then taken out of the furnace to complete the ring rolling process.

[0018] Furthermore, in the preparation process of the small-size ring forgings, after chamfering, the material is loaded into a furnace at an environment not exceeding 1090°C, heated to 1120-1150°C and kept warm for 250-400 minutes before being taken out of the furnace to complete the upsetting and punching processes. During the upsetting and punching process, the deformation amount is 50-75%.

[0019] Furthermore, after completing the upsetting and punching, the steel is loaded into a furnace at a temperature not exceeding 1090°C, heated to 1100-1130°C and kept warm for 235-385 minutes before being taken out of the furnace to complete the horse rack expansion process. During the horse rack expansion process, the deformation amount is 28-35%.

[0020] Furthermore, in the preparation process of the large-size ring forgings, after chamfering, the material is loaded into a furnace at an environment not exceeding 1090°C, heated to 1120-1150°C and kept warm for 385-600 minutes before being taken out of the furnace to complete the upsetting and punching processes. During the upsetting and punching process, the deformation amount is 50-92%.

[0021] Furthermore, after completing the upsetting and punching, the steel is loaded into a furnace at an environment not exceeding 1090°C, heated to 1120-1150°C and kept warm for 200-400 minutes before being taken out of the furnace to complete the horse rack hole expansion process. During the horse rack hole expansion process, the deformation amount is 30-44%.

[0022] Furthermore, after the small-sized ring forgings complete the horse frame expansion process, they are loaded into a furnace at an environment not exceeding 1070°C, heated to 1100-1120°C, kept warm for 190-250 minutes, and then taken out of the furnace to complete the ring rolling process.

[0023] Furthermore, among the forging raw materials, in terms of weight percentage of chemical composition, the C content is 0.04-0.10%, the Si content is not more than 0.8%, the Mn content is not more than 0.4%, the S content is not more than 0.01%, the P content is not more than 0.01%, the Cr content is 18.0-21.0%, the Co content is not more than 1.0%, the B content is not more than 0.008%, the Cu content is not more than 0.2%, the Fe content is not more than 1.5%, the Ti content is 1.8-2.7%, the Al content is 1.0-1.8% and the sum of the Al and Ti contents is not less than 3.5%, and the balance is Ni.

[0024] Compared with the prior art, the beneficial effects of the present invention include:

[0025] 1) Ring forgings are divided into large-size ring forgings and small-size ring forgings according to their outer diameters. For large-size ring forgings, the deformation is controlled to be not less than 25% in the final rolling stage of the ring rolling process, and the internal grains will undergo dynamic recrystallization under the action of high temperature and large deformation, thereby refining the internal grains; for small-size ring forgings, the deformation is controlled to be not more than 25% in the ring rolling process and the production is carried out in combination with hot material recycling. Although the internal grains do not undergo dynamic recrystallization, small deformations and more high-energy dislocations are generated near the grain boundaries. After the hot material recycling, quasi-dynamic recrystallization can occur inside the forging, thereby achieving the effect of refining the internal grains.

[0026] 2) The ring forgings produced are fine-grained high-temperature alloy forgings, whose microstructure is more uniform, reducing segregation, making the precipitated phase fine and evenly distributed, which helps to improve the mechanical properties and corrosion resistance of the material; and the production cycle of fine-grained high-temperature alloys is relatively short, and a large number of high-performance ones can be produced quickly, thereby improving production efficiency; it can maintain excellent performance in higher temperature environments, making it more widely used in high-temperature working environments such as aerospace, energy, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The disclosure of the present invention is described with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. In the accompanying drawings, the same reference numerals are used to refer to the same components. Among them:

[0028] Figure 1 The schematic diagram shows the preparation process of different sizes of effectively improved miscible or coarse-grained high-temperature alloy ring forgings;

[0029] Figure 2 The metallographic structure of the forging obtained in Example 1 is schematically shown;

[0030] Figure 3 The metallographic structure of the forging obtained in Example 2 is schematically shown;

[0031] Figure 4 The metallographic structure of the forging obtained in Example 3 is schematically shown;

[0032] Figure 5 The metallographic structure of the forging obtained in Example 4 is schematically shown. DETAILED DESCRIPTION

[0033] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific implementation modes and drawings are only exemplary descriptions of the technical solution of the present invention, and should not be regarded as the whole of the present invention or as a limitation or restriction to the technical solution of the present invention.

[0034] Methods for preparing forgings of miscible or coarse-grained high-temperature alloy rings of different sizes, such as Figure 1 As shown, after first determining the size of the ring forging according to the outer diameter, the preparation process of the ring forging is completed according to the preparation method of the ring forging of the corresponding size, specifically:

[0035] The ring forgings include large-size ring forgings and small-size ring forgings. The outer diameter of the large-size ring forgings is greater than 1.5m, and the outer diameter of the small-size ring forgings is not greater than 1.5m.

[0036] Among the raw materials of the aforementioned ring forgings, in terms of weight percentage of chemical components, the C content is 0.04-0.10%, the Si content is not more than 0.8%, the Mn content is not more than 0.4%, the S content is not more than 0.01%, the P content is not more than 0.01%, the Cr content is 18.0-21.0%, the Co content is not more than 1.0%, the B content is not more than 0.008%, the Cu content is not more than 0.2%, the Fe content is not more than 1.5%, the Ti content is 1.8-2.7%, the Al content is 1.0-1.8% and the sum of the Al and Ti contents is not less than 3.5%, and the balance is Ni.

[0037] For large-sized ring forgings, after the forging and hole expansion process, the deformation of the final rolling process during the ring rolling process is not less than 25%. During the forging process, the temperature of large-sized ring forgings drops significantly. In order to ensure the final forging temperature of forging, high-temperature forging is required to ensure that the temperature remains within a good temperature range. When the temperature of the high-temperature alloy forging is high, the grains inside it will grow. After that, with the large deformation during the final rolling process, the internal grains will undergo dynamic recrystallization under the combined effect of high temperature and large deformation, thereby making the internal grains of large-sized ring forgings refined / homogeneous.

[0038] For small-sized ring forgings, after the forging and hole expansion process is completed, during the ring rolling process, the deformation of the final rolling process is less than 25%, and after the medium pressure process is completed, the ring forgings are returned to the furnace and kept warm at 1050℃ according to the effective wall thickness of the ring forgings. Because the deformation of small-sized ring forgings is generally small, under the condition of small deformation, if the same high-temperature forging method as large-sized ring forgings is maintained, dynamic recrystallization cannot occur for small-sized forgings. Only low-temperature forging can be selected near the grain growth temperature. Although dynamic recrystallization does not occur in the internal grains in the later stage of low-temperature forging and small deformation ring rolling, more high-energy dislocations have actually been generated near the grain boundaries through small deformation. However, with the completion of forging, there is a lack of sufficient energy to further cause dynamic recrystallization. At this time, by returning the forged forgings to the furnace at a temperature below the grain growth temperature, and keeping warm for a certain period of time according to different effective wall thicknesses, quasi-dynamic recrystallization can occur inside the forgings, thereby refining / homogenizing the internal grains of small-sized ring forgings.

[0039] The relationship between the aforementioned holding time and the effective wall thickness of the ring forging is shown in the following formula:

[0040]

[0041] Where T is the holding time in min, and x is the effective wall thickness of the ring forging in mm.

[0042] The technical effects of the present application are described in detail below with reference to the embodiments.

[0043] Example 1 (gradual cooling + high temperature forging + large deformation)

[0044] This embodiment 1 provides a method for preparing a large-sized miscible / coarse-grained high-temperature alloy ring forging. The crystal structure of the obtained forging is as follows: Figure 2 As shown, after forging according to this method, compared with Example 4, the grain size of the forging was significantly improved. (From 0-1 grade mixed crystal products to 4-6 grade fine crystal products)

[0045]

[0046] Example 2

[0047] Example 2 (gradual cooling + low temperature forging + small deformation + hot material return to the furnace)

[0048] This embodiment 2 provides a method for preparing a small-sized easily miscible / coarse-grained high-temperature alloy ring forging. The crystal phase structure of the obtained forging is as follows: Figure 3 As shown, after forging according to this method, compared with Example 3, the grain size of the forging was significantly improved. (From 0-1 grade mixed crystal products to 4-6 grade fine crystal products)

[0049]

[0050] Example 3 (Forging production method of small-sized high-temperature alloy ring forgings)

[0051] This embodiment 3 provides a method for preparing a small-sized conventional high-temperature alloy ring forging. The crystal structure of the obtained forging is as follows: Figure 4 As shown, after forging according to this method, the grain size of the forging is 0-1 and the mixed crystal is serious.

[0052]

[0053] Example 4 (Preparation method of large-size traditional high-temperature ring forging)

[0054] This embodiment 4 provides a method for preparing a large-scale conventional high-temperature alloy ring forging. The crystal structure of the obtained forging is as follows: Figure 5 As shown, after forging according to this method, the grain size of the forging is 0-1 and the mixed crystal is serious.

[0055]

[0056] The technical scope of the present invention is not limited to the contents in the above description. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical idea of ​​the present invention, and these deformations and modifications should all fall within the protection scope of the present invention.

Claims

1. A method for preparing forgings of easily miscible or coarse-grained high-temperature alloy rings of different sizes, characterized in that: The size of the ring forging is determined according to the outer diameter, and then the preparation process of the ring forging is completed according to the preparation method of the ring forging of the corresponding size; The ring forgings include large-size ring forgings and small-size ring forgings, wherein the outer diameter of the large-size ring forgings is greater than 1.5 m, and the outer diameter of the small-size ring forgings is not greater than 1.5 m; After the large-size ring forging is completed through forging and hole expansion, during the ring rolling process, the deformation amount of the final rolling process is not less than 25%; After the small-size ring forging is completed with the forging and hole expansion process, during the ring rolling process, the deformation of the final rolling process is less than 25%, and after the final rolling process is completed, the obtained ring forging is returned to the furnace and kept warm at 1050° C. for at least 15 minutes.

2. The method for preparing forgings of different sizes of easily miscible or coarse-grained high-temperature alloy rings according to claim 1 is characterized in that: The relationship between the holding time of the small-sized ring forging and the effective wall thickness of the ring forging is as follows: Where T is the holding time and x is the effective wall thickness of the ring forging.

3. The method for preparing forgings of different sizes of easily miscible or coarse-grained high-temperature alloy rings according to claim 1, characterized in that: After the small-sized ring forgings complete the horse frame expansion process, they are loaded into the furnace at an environment not exceeding 1040°C, heated to 1080-1100°C, and kept warm for 235-385 minutes before being taken out of the furnace to complete the ring rolling process.

4. The method for preparing forgings of different sizes of easily miscible or coarse-grained high-temperature alloy rings according to claim 3 is characterized in that: In the preparation process of the small-size ring forgings, after chamfering, the material is loaded into a furnace at an environment not exceeding 1090°C, heated to 1120-1150°C and kept warm for 250-400 minutes before being taken out of the furnace to complete the upsetting and punching processes. During the upsetting and punching process, the deformation amount is 50-75%.

5. The method for preparing forgings of different sizes of easily miscible or coarse-grained high-temperature alloy rings according to claim 4 is characterized in that: After completing the upsetting and punching, the furnace is loaded at a temperature not exceeding 1090°C, the temperature is raised to 1100-1130°C and kept at this temperature for 235-385 minutes before being taken out of the furnace to complete the horse rack hole expansion process. During the horse rack hole expansion process, the deformation amount is 28-35%.

6. The method for preparing forgings of different sizes of easily miscible or coarse-grained high-temperature alloy rings according to claim 1, characterized in that: In the preparation process of the large-size ring forgings, after chamfering, the material is loaded into a furnace at an environment not exceeding 1090°C, heated to 1120-1150°C and kept warm for 385-600 minutes before being taken out of the furnace to complete the upsetting and punching processes. During the upsetting and punching process, the deformation amount is 50-92%.

7. The method for preparing forgings of different sizes of easily miscible or coarse-grained high-temperature alloy rings according to claim 6, characterized in that: After completing the upsetting and punching, the furnace is loaded at an environment of no more than 1090°C, the temperature is raised to 1120-1150°C and kept warm for 200-400 minutes before being taken out of the furnace to complete the horse rack hole expansion process. During the horse rack hole expansion process, the deformation amount is 30-44%.

8. The method for preparing forgings of different sizes of effectively improved miscible or coarse-grained high-temperature alloy rings according to claim 7, characterized in that: After the small-sized ring forgings have completed the horse frame expansion process, they are loaded into the furnace at an environment not exceeding 1070°C, heated to 1100-1120°C, and kept warm for 190-250 minutes before being taken out of the furnace to complete the ring rolling process.

9. The method for preparing forgings of different sizes of easily miscible or coarse-grained high-temperature alloy rings according to any one of claims 1 to 8, characterized in that: Among the forging raw materials, in terms of weight percentage of chemical composition, the C content is 0.04-0.10%, the Si content is not more than 0.8%, the Mn content is not more than 0.4%, the S content is not more than 0.01%, the P content is not more than 0.01%, the Cr content is 18.0-21.0%, the Co content is not more than 1.0%, the B content is not more than 0.008%, the Cu content is not more than 0.2%, the Fe content is not more than 1.5%, the Ti content is 1.8-2.7%, the Al content is 1.0-1.8% and the sum of the Al and Ti contents is not less than 3.5%, and the balance is Ni.

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