Method for manufacturing hot-forged material

Abstract

Provided is a method for manufacturing a hot forging material that enables efficient hot forging while preventing defects such as cracking, even when a difficult-to-machine alloy is used as a blank for hot forging. A method for manufacturing a hot forging material includes: a heating step of heating a pre-heating blank to be hot forged to a hot forging temperature in a heating furnace; a heat-resistant insulating material bonding step of bonding a heat-resistant insulating material to at least a part of the surface of the blank for forging taken out of the heating furnace, thereby producing a blank for hot forging; and a hot forging step of compressing a part or the entirety of the blank for hot forging using any one of a die, an anvil, and a tool, thereby shaping into a prescribed shape.

Description

Technical Field

[0001] This invention relates to a method for manufacturing hot-forged materials, and particularly to a method for manufacturing hot-forged materials made of difficult-to-machine alloys. Background Technology

[0002] When hot forging a billet heated to its hot forging temperature, there is a problem of reduced hot workability due to the decrease in the billet's temperature. Therefore, various solutions to prevent this temperature drop have been proposed. For example, Japanese Patent Publication No. 2014-508857 (Patent Document 1) discloses preventing thermal cracking by applying a glass coating to the hot forging billet. As a method of glass coating, glass fabric and glass particles are sequentially arranged on the hot forging billet. Furthermore, Patent Document 1 discloses, as prior art, sealing the hot forging billet inside a metal alloy can before hot working.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Publication No. 2014-508857 Summary of the Invention

[0006] The problem the invention aims to solve

[0007] In Patent Documents 1 and 2, as shown in their embodiments, a glass fabric is wound onto a hot forging blank at room temperature, an inorganic slurry is coated onto the surface of the glass fabric, and the blank is heated to the hot forging temperature in this state to form a glass coating layer. This method is indeed effective in suppressing temperature drop from when the hot forging blank is removed from the furnace until hot forging begins. However, because the glass fabric itself has an insulating effect, the time required to heat to the forging temperature is prolonged; furthermore, as in Patent Documents 1 and 2… Figure 3 The method shown, which involves wrapping the entire structure with glass fiber cloth, has the disadvantage that it is difficult to know the temperature of the hot forging billet itself.

[0008] On the other hand, among representative alloys whose hot workability decreases due to the decrease in temperature from the start of hot forging of the billet heated to the hot forging temperature, and the decrease in temperature during the hot forging process, there are Ni-based alloys and Ti alloys known as difficult-to-machine alloys containing more than 20% γ' phase by volume. These difficult-to-machine alloys are used in aircraft parts and power generation equipment parts due to their excellent high-temperature strength. These applications require larger sizes to improve combustion efficiency and power generation efficiency, and the use of Ni-based alloys containing more than 20% γ' phase by volume (hereinafter referred to as high-γ' content Ni-based alloys) at higher temperatures is being investigated. Hot forging temperature affects the formation of defects such as cracks, especially in high-γ' content Ni-based alloys, where the range of hot forging temperatures is limited. Balancing hot workability and preventing defects such as cracks is important, and methods for efficiently performing hot forging while preventing cracks during hot forging are being sought.

[0009] The purpose of this invention is to provide a method for manufacturing hot forging materials that can be efficiently hot forged while preventing defects such as cracks, even when using difficult-to-machine alloys as hot forging blanks.

[0010] Solution for solving the problem

[0011] This invention was made in view of the above-mentioned technical problems.

[0012] That is, the present invention is a method for manufacturing a hot forging material, comprising: a heating step, wherein a pre-heating billet to be hot forged is heated to a hot forging temperature in a heating furnace; a heat-resistant and heat-insulating material bonding step, wherein a heat-resistant and heat-insulating material is bonded to at least a portion of the surface of a forging billet taken from the heating furnace, thereby forming a hot forging billet; and a hot forging step, wherein a portion or the entire hot forging billet is compressed using any one of a mold, anvil, or tool, thereby forming a predetermined shape.

[0013] In addition, the present invention is a method for manufacturing a hot forging material, wherein the hot forging process is free forging, and in the free forging, the heat-resistant and heat-insulating material is bonded to at least a portion of the surface of the free deformation portion of the forging billet that does not come into contact with any of the mold, anvil, or tool.

[0014] Preferably, the method for manufacturing hot-forged materials also includes a glass lubricant coating process, wherein at least a portion of the surface of the blank to which the heat-resistant and heat-insulating material is to be bonded is coated with glass lubricant before the heating.

[0015] In addition, in this invention, the surface of the heat-resistant insulation material to be bonded to the forging blank may be covered with glass particles.

[0016] The preferred method for manufacturing the heat-resistant and heat-insulating material is a hot-forged material of inorganic fibers.

[0017] The effects of the invention

[0018] According to the present invention, even when using a difficult-to-machine alloy as the billet for hot forging, hot forging can be performed efficiently while preventing defects such as cracks. Attached Figure Description

[0019] Figure 1 This is a schematic diagram illustrating an example of a method for manufacturing the hot-forged material according to the present invention.

[0020] Figure 2 This is a schematic diagram illustrating an example of a method for producing a hot forging billet according to the present invention.

[0021] Figure 3 This is a schematic diagram illustrating an example of a method for producing a hot forging billet according to the present invention. Detailed Implementation

[0022] The present invention will now be described for each step. It should be noted that, as described below, "preheating billet" refers to the billet before it is loaded into the heating furnace, "forging billet" refers to the billet heated to the hot forging temperature in the heating furnace, "hot forging billet" refers to the billet in which heat-resistant and heat-insulating material is bonded to a specified portion to make it suitable for hot forging, and "hot forging material" refers to the forming material formed into a specified shape by a hot forging device.

[0023] <Heating Process>

[0024] First, in this invention, the pre-forging billet to be hot-forged is heated to the hot-forging temperature in a heating furnace. The pre-forging billet can be an ingot, billet, rough forging, powder molded body, etc., and is not particularly limited. The best way to achieve the effects of this invention is with an ingot or billet that has been freely forged into the desired shape. This pre-forging billet is then heated to the hot-forging temperature in the heating furnace. The heating temperature varies depending on the material of the pre-forging billet. For example, if it is a Ni-based alloy, it can be 950℃ to 1180℃; if it is a Ni-based alloy with high γ' content, it can be 1010℃ to 1180℃. Alternatively, if it is a Ti alloy, it can be 900℃ to 1180℃. It should be noted that in this invention, a "heat-resistant insulation material bonding process" is applied after the heating process. In this heat-resistant insulation material bonding process, heat-resistant insulation material is bonded to the forging billet taken from the heating furnace. During the period until the heat-resistant insulation material is bonded, it is preferable that the temperature of the forging billet drops to zero, although in reality the temperature will drop to some extent. Therefore, the hot forging temperature can be set to a temperature approximately 5°C to 100°C higher than the initial forging temperature (forging start temperature). Thus, even if the temperature of the forging billet drops by more than 100°C compared to the forging start temperature without the heat-resistant insulation material being bonded, the temperature drop can be suppressed, thereby maintaining a relatively high temperature during hot forging.

[0025] Furthermore, when the billet material before heating is a Ni-based superheat-resistant alloy, most of the alloy contains Cr in the range of 10% to 35% by mass. To suppress the reaction between oxygen and Cr in the heating furnace during the heating process, it is preferable to keep the oxygen concentration in the heating furnace below 10%, preferably below 8%.

[0026] It should be noted that the surface roughness of the preheated blank should ideally be rougher than a normal finish. This allows for the formation of a small space between the heat-resistant insulation material and the forging blank when the heat-resistant insulation material is bonded to its surface in the next process. The air within this space can then act as an insulating layer. Furthermore, in cases where a glass lubricant coating process (described later) is included, it becomes easier for glass lubricant residue to remain on the uneven surface of the preheated blank. While it is possible to maintain the surface texture during casting and plastic processing, in the case of difficult-to-machine alloys, surface cracks may sometimes occur due to the influence of added elements. Therefore, it is preferable to remove these surface defects, which could cause cracks during hot forging, beforehand by machining. Even if cracks are not observed, it is preferable to adjust the surface roughness of the preheated blank to a roughness greater than a normal finish beforehand by machining the portion where the heat-resistant insulation material will be bonded to its surface in the next process.

[0027] <Bonding process for heat-resistant and heat-insulating materials>

[0028] A hot-forging billet is prepared by heating a pre-heated billet to a hot-forging temperature and then bonding a heat-resistant and insulating material to a specified portion of at least a portion of the surface of the billet after it has been removed from the heating furnace. The bonded portion may be a portion of the surface or the entire surface. Regarding which portion of the surface of the forging billet is bonded with the heat-resistant and insulating material, either of the following two options is preferable.

[0029] The first method prioritizes preventing temperature drops in areas where cracks are predicted to occur. If the time required to bond the heat-resistant insulation material to the forging blank is prolonged, the blank's temperature may sometimes drop, leading to deterioration in hot forgeability. Therefore, it is preferable to bond the heat-resistant insulation material to its surface within the minimum required time without compromising hot forgeability. For example, when placing the hot forging blank on a hot forging apparatus, if there are concerns about heat dissipation from the lower die (lower anvil or lower tool), the heat-resistant insulation material can be bonded to the surface in contact with the lower die (lower anvil or lower tool); if it is a polygonal columnar shape, the material can be bonded to the area including the edges. If it is cylindrical, the material can be bonded to its sides. In other words, the heat-resistant insulation material should be bonded to areas prone to defects such as cracks caused by hot forging. This method is particularly effective for high-γ' Ni-based alloys, which are known to be difficult to machine.

[0030] The second method involves bonding the heat-resistant and insulating material to at least a portion of the surface of the freely deformable portion of the forging billet. In cases where hot forging is free forging, for example, the portion not in contact with the upper die (upper anvil or upper tool) and lower die (lower anvil or lower tool) is allowed to cool naturally in the atmosphere; therefore, this method primarily reduces this temperature drop. For example, in alloys with a wide hot-forging temperature range, such as 718 alloy and Waspaloy alloy, this method helps reduce defects (cracks) because it allows for the maintenance of a sustained heating temperature.

[0031] When choosing the above methods, it is advisable to consider their material and shape.

[0032] By bonding this heat-resistant and heat-insulating material, not only can the precipitation of fine γ' that occurs with the decrease in temperature of the hot forging billet be reduced, but recrystallization of the surface layer of the hot forging billet can also be promoted. Therefore, even for Ni-based alloys with high γ' content, which are known as difficult-to-machine alloys, the occurrence of defects such as cracks can be reduced.

[0033] It should be noted that, in the heat-resistant insulation material bonding process, to facilitate and quickly bond the heat-resistant insulation material, it is preferable to have a glass lubricant present between the heat-resistant insulation material and the bonding surface of the forging blank to which it is bonded. In this case, the glass lubricant primarily functions as an "adhesive." Two methods exist for this purpose, which will be described separately.

[0034] The first method involves a "glass lubricant coating process." This process further includes pre-coating at least a portion of the surface of the blank to which the heat-resistant insulating material is to be bonded with glass lubricant before heating. The glass lubricant acts as a heat-insulating agent after heating, and is therefore particularly effective in the hot forging of difficult-to-machine alloys.

[0035] The second method involves pre-attaching glass particles to the surface of the heat-resistant insulation material to be bonded to the forging blank, and then bonding the heat-resistant insulation material at a specified location. In this method, the glass particles soften and adhere due to the heat retained on the surface of the forging blank, making it effective for hot forging of high-temperature forging alloys such as Ni-based superheat-resistant alloys. It should be noted that methods for attaching glass particles to the heat-resistant insulation material include, for example, scattering glass particles on the surface of the heat-resistant insulation material to be bonded to the forging blank; and coating or spraying (spraying) a glass lubricant containing glass particles. When using a coating or spraying (spraying) method with a glass lubricant, it is preferable to pre-dry the heat-resistant insulation material with the attached glass particles. The method of spraying a glass lubricant is particularly preferred because it allows for uniform attachment of glass particles to the surface of the heat-resistant insulation material to be bonded to the forging blank.

[0036] It should be noted that, of course, the above-mentioned "glass lubricant coating process" and "adhering glass particles to the surface of the heat-resistant insulation material to be bonded to the forging blank" can also be combined.

[0037] The heat-resistant and insulating material is preferably an inorganic fiber. It should be noted that "inorganic fiber" mentioned in this invention includes glass fiber, ceramic fiber, etc., and ceramic fiber with excellent heat insulation properties is preferred. Among ceramic fibers, for example, KAOWOOL (registered trademark: hereinafter referred to as "kaolin cotton") is particularly preferred from the perspective of ease of use and low cost. If the heat-resistant and insulating material is an inorganic fiber, even if the surface roughness of the forging blank is somewhat rough, it is easy to adhere along its surface shape. The fibers easily hang on the unevenness of the forging blank surface and are lightweight, therefore, for example, they are also easy to adhere to the side of the forging blank.

[0038] Furthermore, if kaolin wool is bonded to at least a portion of the surface of the forging billet taken from the heating furnace as in this invention, the kaolin wool remains intact at the beginning of hot forging, and the temperature drop of the hot forging billet during the hot forging process can be suppressed. If kaolin wool is pre-prepared before being loaded into the heating furnace as in the conventional example, it will become easily broken during transport for hot forging, depending on the relationship between temperature and time.

[0039] <Hot Forging Process>

[0040] Using the aforementioned hot forging billet, a portion or all of the billet is compressed using any one of a die, anvil, or tool to form a predetermined shape. The forging apparatus used is preferably a large-scale hot forging apparatus with a forging load of several thousand tons or more, capable of forming even difficult-to-machine alloys into predetermined shapes.

[0041] Furthermore, in this invention, the hot forging process is preferably free forging. During free forging, the hot forging billet is heavy, has a large area for heat dissipation to the atmosphere, and requires a large amount of processing. Therefore, bonding a heat-resistant insulating material is highly effective in suppressing the temperature drop of the hot forging billet. In this case, as described above, for example, if hot forging is being performed on conventional Ni-based alloys with a wide hot forging temperature range, such as 718 alloy or Vosparoi alloy, it is preferable to pre-bond the bonding heat-resistant insulating material to at least a portion of the surface of the free-deformed portion of the forging billet that will not come into contact with any of the die, anvil, or tool during the free forging.

[0042] Example

[0043] The present invention will be described in detail through the embodiments. It should be noted that the temperature measurement of the examples of the present invention shown in the following embodiments is centered on the part of the invention without the heat-resistant insulation material, or the part that peels off during or after hot forging.

[0044] Example 1

[0045] In addition to Alloy 718 (Cr 18.5 wt%) and Alloy Vosparoi (Cr 19.5 wt%), a high-content Ni-based alloy (hereinafter referred to as Alloy A) consisting of Cr 13.5 wt%, Co 25.0 wt%, Mo 2.8 wt%, W 1.2 wt%, Ti 6.2 wt%, Al 2.3 wt%, C 0.015 wt%, B 0.015 wt%, Zr 0.03 wt%, the balance Ni, and unavoidable impurities, and containing approximately 49.5 vol% γ' phase, was prepared as the preheating billet. All preheating billets were materials that were machined from ingots to specified dimensions, with a surface roughness equivalent to rough machining. It should be noted that materials with an L / D ratio of 3 or less were used as preheating billets for upsetting by free hot forging.

[0046] Before the heating process, as a glass lubricant coating process, a glass lubricant with a thickness of approximately 50–200 μm is applied to both end faces (the faces that will contact the anvil or tool) of the billet at a temperature below 200°C before heating (glass lubricant coating process). The billet is then heated in a furnace to a specified hot forging temperature (heating process). The oxygen concentration at this time is controlled at 2%–8%. Regarding the heating temperature (hot forging temperature), it is set to 1100°C for Alloy A and Alloy 718, and 1150°C for Alloy Vosparoi, with a holding time of 2–9 hours. The time to reach the hot forging temperature is approximately 8 hours, which allows for reaching the specified temperature more than 10 hours earlier compared to existing methods that wrap the entire surface with heat-resistant insulation material.

[0047] Next, heat-resistant and heat-insulating material 11 is bonded to the surfaces of both end faces of the forging blank 1 taken from the heating furnace using a manipulator, thereby producing the hot forging blank 2 (heat-resistant and heat-insulating material bonding process). The heat-resistant and heat-insulating material is set as kaolin cotton (inorganic fiber), such as... Figure 1 As shown, it is bonded to the surface that contacts the anvil or tool to suppress the temperature drop of the hot forging billet and to suppress heat dissipation caused by contact with the anvil or tool. It should be noted that, through the pre-coated glass lubricant, the kaolin cotton bonded to the forging billet in a short time without any problems. Therefore, the temperature drop was only about 5°C to 10°C compared to the usual temperature drop until it was left to stand, which is not considered to pose any obstacle to hot forging.

[0048] Using the aforementioned hot forging billet, upsetting is performed via hot free forging. The hot forging billet is placed on the lower anvil of the hot forging apparatus, and an upsetting tool is placed on the upper end face of the hot forging die. Then, free forging is performed using a hot forging apparatus with a pressure capacity of 4000 tons to produce a rough forging (hot forging material 3) for the next hot forging process (hot forging process). The portions of the lower anvil and upsetting tool that are not in contact with the hot forging billet are free deformation areas. The forging start temperature is approximately 1000°C, and the forging temperature during hot forging is approximately 950°C to 980°C. As described above, the portions in contact with the lower anvil and the portions in contact with the upsetting tool on the upper end face are almost free of surface defects such as wrinkles (cracks) at the ends of the hot forging material because the kaolin cotton suppresses heat dissipation.

[0049] Example 2

[0050] For an example using Vosparoi alloy and bonded with heat-resistant insulation material (Example 1 of the present invention) and an example without bonded heat-resistant insulation material (Comparative Example 1), the temperature changes during hot forging and the generation of defects (cracks) in the hot forging material were compared.

[0051] The forging blanks used are all materials that have been machined from ingots to specified dimensions, with a surface roughness equivalent to that of rough machining. It should be noted that materials with an L / D ratio of 1.5 or less are used as the pre-heating blanks for upsetting based on hot free forging.

[0052] Before the heating process, as a glass lubricant coating process, a glass lubricant with a thickness of approximately 50 μm to 200 μm is applied to both end faces (the faces in contact with the anvil or tool) and the outer peripheral surface to which the heat-resistant insulation material is to be bonded on the pre-heating blank of Example 1 of the present invention (glass lubricant coating process). The pre-heating blank is heated to a specified hot forging temperature in a heating furnace (heating process). The oxygen concentration at this time is controlled at 2% to 8%. The heating temperature (hot forging temperature) is set to 1150°C, and the holding time is set to 2 to 4 hours. The heating time to the forging temperature is approximately 8 hours.

[0053] Next, as Figure 2 As shown, two pieces of kaolin (inorganic fiber) of different lengths (11A longer, 11B shorter) are overlapped in a cross shape to form a heat-resistant insulation material 11. The forging blank 1 of Example 2 of this invention, taken from the heating furnace using a manipulator, is placed on the overlapped portion. The inorganic insulation material is bent in the direction of the black arrow, and the heat-resistant insulation material is bonded to the surface of both end faces and the outer peripheral surface of the forging blank. The shorter heat-resistant insulation material 11B, to achieve a length close to the entire height of the forging blank, overlaps the longer heat-resistant insulation material 11A on the upper end face of the forging blank, covering almost the entire surface of the forging blank, thus producing a hot forging blank (heat-resistant insulation material bonding process). This suppresses the temperature drop of the hot forging blank, the heat dissipation due to contact with the anvil or tool, and the heat dissipation due to contact with the handle of the manipulator. It should be noted that by attaching glass particles to the surface of the kaolin wool to be bonded to the forging blank on top of a pre-coated glass lubricant, the kaolin wool and the forging blank bonded together quickly and without problems. Therefore, compared to the temperature drop that usually occurs until the blank is left to stand, the temperature only decreased by about 5°C to 10°C, which is not considered to pose any obstacle to hot forging. It should also be noted that the forging blank in Comparative Example 1 was not coated with a heat-resistant insulating material.

[0054] Hot free forging is performed using the aforementioned hot forging billet. The hot forging billet is placed on the lower anvil of the hot forging apparatus, and an upsetting tool is placed on the upper end face of the hot forging die. Then, free forging is performed using a hot forging apparatus with a pressure capacity of 10,000 tons to produce a rough forging (hot forging material) for the next hot forging process (hot forging process). The portion of the lower anvil and upsetting tool that is not in contact with the hot forging billet is the free deformation zone. The forging start temperature is approximately 1050°C, and the forging temperature during hot forging is approximately 1000°C.

[0055] The temperature of the hot forging billet immediately after upsetting was measured using a radiation thermometer. In Example 1 of the present invention, it was approximately 1090°C to 1120°C, and in Comparative Example 1, it was 950°C to 990°C. Example 1 of the present invention was able to maintain the temperature during hot forging at a level approximately 100°C or higher. The cracking of the produced hot forging material was examined. In the hot forging material of Example 1 of the present invention, cracks were virtually invisible to the naked eye. However, in the hot forging material of Comparative Example 1, cracks that could be visually identified were visible on both end faces of the forging billet in contact with the anvil or tool, and on the side face of the forging billet held by the manipulator.

[0056] Example 3

[0057] For an example using Vosparoi alloy and bonded with heat-resistant insulation material (Example 2 of the present invention) and an example without bonded heat-resistant insulation material (Comparative Example 2), the temperature changes during elongation forging and the generation of defects (cracks) in the hot-forged material were compared.

[0058] The preheated billet used is a material that has been machined into specified dimensions after upsetting, and its surface roughness is set to be equivalent to that of rough machining.

[0059] Prior to the heating process, as a glass lubricant coating process, a glass lubricant with a thickness of approximately 50 μm to 200 μm is applied to both end faces of the pre-heating blank and the portion to which the heat-resistant insulation material is to be bonded (glass lubricant coating process). The pre-heating blank is then heated to a specified hot forging temperature in a heating furnace (heating process). The oxygen concentration at this time is controlled at 2% to 8%. The heating temperature is set to 1150°C, and the holding time is set to 2 to 4 hours. The heating time to the forging temperature is approximately 8 hours.

[0060] Next, as Figure 3 As shown, heat-resistant insulation material 11 is prepared. The forging blank 1 of Example 2 of the present invention, taken from the heating furnace using a manipulator, is placed on the heat-resistant insulation material 11. The heat-resistant insulation material is bent in the direction of the black arrow, and the heat-resistant insulation material is bonded to the outer peripheral surface, thereby producing a hot forging blank (heat-resistant insulation material bonding process). The heat-resistant insulation material is set as kaolin cotton (inorganic fiber), such as... Figure 3 As shown, it was bonded to the outer peripheral surface (the free deformation portion of the forging blank), thus suppressing the temperature drop of the hot forging blank and the heat dissipation caused by contact with the handle of the actuator. It should be noted that by attaching glass particles to the surface of the kaolin cotton to be bonded to the forging blank on top of a pre-coated glass lubricant, the kaolin cotton and the forging blank bonded quickly and without problems. Therefore, compared to the temperature drop that usually occurs until placement, the temperature only decreased by about 5°C to 10°C, and it was determined that this would not pose an obstacle to hot forging. It should be noted that the forging blank in Comparative Example 2 was not coated with a heat-resistant insulating material.

[0061] Hot forging is performed using the aforementioned hot forging billet. The hot forging billet is held by the sides of its sides using the lower and upper anvils of a hot forging apparatus, and then pressed and stretched using a 4000-ton hot forging apparatus to produce a rough forging (hot forging material) for the next hot forging process (hot forging process). The initial forging temperature for the uncoated portion is approximately 1050°C, and the temperature of the forging billet where the coating falls off during hot forging is approximately 1080°C to 1020°C.

[0062] The temperature of the hot-forged billet immediately after hot forging was measured using a radiation thermometer. The results showed that in Example 2 of this invention, the temperature was 950°C to 980°C, while in Comparative Example 2, it was 900°C to 950°C. Example 2 of this invention was able to maintain the temperature during hot forging at a high level of approximately 50°C to 80°C. The cracking of the produced hot-forged material was examined. The results showed that almost no cracks were visually detected in the hot-forged material of Example 2 of this invention, while visually detectable cracks were observed throughout the hot-forged material of Comparative Example 2.

[0063] As can be seen from the above, the hot forging material manufacturing method of the present invention, as described above, can efficiently perform hot forging while preventing defects such as cracks, even when using a difficult-to-machine alloy as the hot forging blank.

[0064] 1. Forging billet

[0065] 2. Hot forging billets

[0066] 3. Hot Forging Materials

[0067] 11 Heat-resistant and heat-insulating materials

Claims

1. A method for manufacturing a hot-forged material, comprising: The heating process involves heating the billet to the hot forging temperature in a heating furnace. A heat-resistant and heat-insulating material bonding process involves bonding a heat-resistant and heat-insulating material to at least a portion of the surface of a forging blank removed from the heating furnace, thereby producing a hot-forging blank. The heat-resistant and heat-insulating material is an inorganic fiber, and glass particles are attached to the surface of the heat-resistant and heat-insulating material to be bonded to the forging blank. This is achieved by dispersing the glass particles on the surface of the heat-resistant and heat-insulating material. The hot forging process involves using a die or anvil to compress a portion or all of the hot forging billet, thereby shaping it into a specified form.

2. A method for manufacturing a hot-forged material, comprising: The heating process involves heating the billet to the hot forging temperature in a heating furnace. A heat-resistant and heat-insulating material bonding process involves bonding a heat-resistant and heat-insulating material to at least a portion of the surface of a forging blank removed from the heating furnace, thereby producing a hot-forging blank. The heat-resistant and heat-insulating material is an inorganic fiber, and glass particles are attached to the surface of the heat-resistant and heat-insulating material to be bonded to the forging blank. This is achieved by dispersing the glass particles on the surface of the heat-resistant and heat-insulating material. The hot forging process involves using upsetting tools to compress a portion or the entirety of the hot forging billet, thereby shaping it into a specified form.

3. A method for manufacturing a hot-forged material, comprising: The heating process involves heating the billet to the hot forging temperature in a heating furnace. A heat-resistant and heat-insulating material bonding process involves bonding a heat-resistant and heat-insulating material to at least a portion of the surface of a forging blank removed from the heating furnace, thereby forming a hot-forging blank. The heat-resistant and heat-insulating material is an inorganic fiber, and glass particles are adhered to the surface of the heat-resistant and heat-insulating material to be bonded to the forging blank. This process is carried out by coating or spraying a glass lubricant containing glass particles onto the surface of the heat-resistant and heat-insulating material, followed by drying the heat-resistant and heat-insulating material with the glass particles attached. The hot forging process involves using a die or anvil to compress a portion or all of the hot forging billet, thereby shaping it into a specified form.

4. A method for manufacturing a hot-forged material, comprising: The heating process involves heating the billet to the hot forging temperature in a heating furnace. A heat-resistant and heat-insulating material bonding process involves bonding a heat-resistant and heat-insulating material to at least a portion of the surface of a forging blank removed from the heating furnace, thereby forming a hot-forging blank. The heat-resistant and heat-insulating material is an inorganic fiber, and glass particles are adhered to the surface of the heat-resistant and heat-insulating material to be bonded to the forging blank. This process is carried out by coating or spraying a glass lubricant containing glass particles onto the surface of the heat-resistant and heat-insulating material, followed by drying the heat-resistant and heat-insulating material with the glass particles attached. The hot forging process involves using upsetting tools to compress a portion or the entirety of the hot forging billet, thereby shaping it into a specified form.

5. The method for manufacturing hot-forged materials according to claim 1 or 3, wherein, The hot forging process is free forging, in which the heat-resistant and heat-insulating material is bonded to at least a portion of the surface of the free deformation portion of the forging billet that does not contact the die or anvil.

6. The method for manufacturing hot-forged materials according to claim 2 or 4, wherein, The hot forging process is free forging, in which the heat-resistant and heat-insulating material is bonded to at least a portion of the surface of the free deformation portion of the forging billet that does not come into contact with the upsetting tool.

7. The method for manufacturing a hot-forged material according to any one of claims 1-4, further comprising a glass lubricant coating step, wherein at least a portion of the surface of the blank to which the heat-resistant and heat-insulating material is to be bonded is coated with glass lubricant before the heating.

8. The method for manufacturing hot forging material according to claim 5, further comprising a glass lubricant coating process, wherein at least a portion of the surface of the blank to which the heat-resistant and heat-insulating material is to be bonded is coated with glass lubricant before heating.

9. The method for manufacturing hot-forged material according to claim 6, further comprising a glass lubricant coating process, wherein at least a portion of the surface of the blank to which the heat-resistant and heat-insulating material is to be bonded is coated with glass lubricant before heating.

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