JP6694584B2 - Mold fixing device and method for manufacturing forged product - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a die fixing device used for hot forging and the like and a method for manufacturing a forged product.

  In recent years, the demand for large-sized hot forged products that constitute jet engines for medium and large aircraft, steam turbines for power plants, etc., has increased significantly. For example, the turbine disk of an aircraft jet engine is in the form of a rotary body and has a diameter of more than 1 meter. Furthermore, since nickel-base superalloys, titanium alloys, etc. used for these purposes are difficult-to-process materials, use a heated mold to suppress the temperature drop of the heated forging material during the forging. Hot die forging, isothermal forging in which the temperature of the die is controlled within a predetermined range for forging, and the like are applied.

As described above, the mold device used when the mold is heated and forged includes a heat insulating structure between the mold and the platen of the press main body in order to prevent heat from escaping from the heated mold. Is provided (for example, Japanese Patent Laid-Open No. 2006-192502 (Patent Document 1)). In Patent Document 1, in order to reduce the thickness of the heat insulating means while ensuring heat insulating properties, different types of heat insulating means such as ceramics and mica are placed between the mold and the supporting element (platen) of the mold. Is disclosed.
Further, Japanese Patent Laid-Open No. 2013-49071 (Patent Document 2) discloses a plurality of heat insulating materials, a holding frame for holding the outer periphery thereof, and a bottom plate and a presser for the purpose of improving the strength and durability of the heat insulating structure. Disclosed is a heat insulating structure integrated with a plate. Examples of the heat insulating material and the holding frame here are zirconia ceramics and stainless steel, respectively.

JP, 2006-192502, A JP, 2013-49071, A

However, when the forging load is large as in the case of manufacturing a large forged product, the strength of the heat insulating material is insufficient with the configuration described in Patent Document 1. On the other hand, if an attempt is made to supplement the strength of the heat insulating material with the frame of the steel for molds as in Patent Document 2, it is impossible to sufficiently suppress the decrease of the mold temperature due to the heat transfer through the frame. The problem arises.
Therefore, the present invention, in forging using a heated die, an object of the present invention is to provide a die fixing device that can withstand a large forging load and a method for manufacturing a forged product while suppressing a decrease in die temperature. And

  The present invention is a mold fixing device for fixing a heated mold, comprising a titanium alloy plate arranged on a surface in contact with the mold, and a hot mold steel for supporting the titanium alloy plate. It has a base material consisting of.

Further, in the mold fixing device, it is preferable that the titanium alloy plate is arranged in a recess provided in the base material.
Further, in the mold fixing device, it is preferable that the titanium alloy plate is composed of a plurality of pieces.
Further, in the mold fixing device, it is preferable that a heat insulating material having a thermal conductivity lower than that of the titanium alloy is arranged in a part between the titanium alloy plate and the base material.

  Another aspect of the present invention is a method for manufacturing a forged product in which a heated forging material is hot forged with a die, the first step of heating the die to fix the die to a die fixing device, and heating the die. A forging material is placed on the die, and a third step of pressing down the forging material with the die, wherein the die device is arranged on a surface in contact with the die. And a base material made of hot die steel for supporting the titanium alloy plate.

  Further, in the method for manufacturing a forged product, it is preferable that a heat insulating material having a lower thermal conductivity than that of the titanium alloy is arranged in a part between the titanium alloy plate and the base material.

  According to the die fixing device and the method for manufacturing a forged product of the present invention, in forging using a heated die, it is possible to suppress the decrease in die temperature and forge with a large load.

It is a figure which shows one Embodiment of the die fixing apparatus which concerns on this invention. It is a figure which shows other embodiment of the metal mold fixing apparatus which concerns on this invention. It is a figure which shows other embodiment of the metal mold fixing apparatus which concerns on this invention. It is a figure which shows other embodiment of the metal mold fixing apparatus which concerns on this invention. It is a figure which shows the structural example of the press used for the manufacturing method of a forged product. It is a figure which shows the temperature transition of the metal mold | die mounted in the metal mold fixing device.

The present invention is a mold fixing device for fixing a heated mold, comprising a titanium alloy plate arranged on a surface in contact with the mold, and a hot mold steel for supporting the titanium alloy plate. A mold fixing device having a base material. Titanium alloy has a lower thermal conductivity than that of hot die steel and thus functions as a heat insulating material. Moreover, since it is excellent in high temperature strength and can withstand a high load, it can be arranged on the surface in contact with the mold. That is, since there is no need to cover with hot die steel, the heat insulating property of the titanium alloy can be effectively utilized.
Even when the mold fixing device is used on the upper mold side and the titanium alloy plate is on the lower side of the base material, the base material is the titanium alloy plate as long as the titanium alloy plate is fixed to the base material. Treat as “supporting”.

The mold fixing device according to the present embodiment is for fixing a heated mold to a press body in hot forging or the like using a mold having a carved surface. The hot forging mentioned here includes hot pressing, isothermal forging, hot die and the like. As a mode of fixing the heated mold, in addition to a mode of fixing the mold heated in a heating furnace or the like to the press body in advance, the mold is fixed to the press machine body in advance and fixed to the press machine body. A mode in which the mold is heated in the heated state is also included.
Hereinafter, embodiments of the mold fixing device according to the present invention will be specifically described with reference to the drawings, but the present invention is not limited thereto. Further, the respective configurations described in this embodiment can be combined with each other as long as the functions thereof are not impaired.

  FIG. 1 shows an embodiment of the mold fixing device. FIG. 1A is a plan view of the mold fixing device seen from the vertical direction (z direction), and FIG. 1B is an xz sectional view taken along the line AA in FIG. 1A. The mold fixing device 100 has a titanium alloy plate 1 arranged on a surface in contact with the mold, and a base member 2 made of hot mold steel for supporting the titanium alloy plate 1. The mold fixing device 100 on which the mold is placed is also referred to as a pressure receiving plate. Since the titanium alloy plate 1 is not covered with hot forging die steel or the like, it is exposed on the surface of the die fixing device 100 and directly contacts the placed die. The titanium alloy plate 1 is fixed to the base material 2 by a fixing jig (not shown) such as a bolt, and the mold fixing device 100 is also fixed to the press body by a fixing jig such as a bolt and a clamp. The mold fixing device 100 can be used for either the lower mold or the upper mold, but it is more preferable to use it for both the lower mold and the upper mold in order to enhance the heat insulating effect.

  The material of the hot die steel forming the base material 2 is not particularly limited, and in consideration of strength and cost, hot die steels such as SKD61 and SKT4 specified in JIS G4404 and The modified steel can be used. Also, the material of the titanium alloy plate 1 is not particularly limited. For example, Ti-5Al-2.5Sn, Ti-15V-3Cr-3Sn-3Al, Ti-6Al-4V, and other alloys containing the most Ti in mass% content can be used. The heat conductivity of the hot die steel such as SKD61 is about 30 W / (m · K), whereas the heat conductivity of the titanium alloy containing Ti as the main component is 8 W / (M · K) or less, which is 1/3 or less of that of hot die steel. Therefore, the titanium alloy plate 1 functions as a heat insulating material. Moreover, since the above-mentioned titanium alloy generally has a proof stress of 900 MPa or more, the titanium alloy has sufficient strength to bear a forging load. Therefore, according to the die fixing device 100 including the titanium alloy plate shown in FIG. 1, in hot forging using a heated die, suppression of die temperature decrease and forging under a large load are compatible. It will be possible.

In the embodiment shown in FIG. 1, the outer shapes of the titanium alloy plate 1 and the base material 2 are quadrangular for ease of handling, but the present invention is not limited to this. Further, the outer shape of the mold mounted on the mold fixing device 100 may be circular or square. If a part of the mold contacts the titanium alloy plate 1 and a part contacts the base material 2 when the mold is placed on the mold fixing device, the base material 2 receives part of the forging load. It is also possible to handle high forging loads. However, in order to efficiently exhibit the heat insulating effect of the titanium alloy plate 1, when the mold is placed on the mold fixing device 100, the outer edge of the bottom surface of the mold is located inside the outer edge of the titanium alloy plate 1. It is preferable to set the size, shape, and arrangement of the titanium alloy plate 1 so that the titanium alloy plate 1 is positioned, that is, the mold does not protrude from the outer edge of the titanium alloy plate 1.
The presence of the titanium alloy plate 1 exerts a heat insulating effect, and since the titanium alloy plate 1 is supported by the base material 2, the thickness (dimension in the z direction) of the titanium alloy plate is not particularly limited. Absent. The thickness is preferably 10 mm or more from the viewpoint of further enhancing the heat insulating effect and the ease of manufacturing. On the other hand, since the material cost increases as the titanium alloy plate 1 becomes thicker, the thickness of the titanium alloy plate is preferably 30 mm or less.

  Since the titanium alloy plate 1 has sufficient strength, a configuration in which the titanium alloy plate 1 is arranged on the surface of the base material 2 without being surrounded by a strength auxiliary member such as hot die steel is also applicable. However, by adopting the configuration in which the titanium alloy plate 1 is arranged in the concave portion 4 provided in the base material as in the embodiment shown in FIG. 1, it becomes possible to withstand a larger forging load. Further, even if the titanium alloy plate 1 is cracked during hot forging, the titanium alloy plate remains in the recesses 4, so that the heat insulating performance and the function of the mold fixing device can be maintained. In the embodiment shown in FIG. 1, the surface of the titanium alloy plate 1 inserted in the recess is substantially flush with the surface of the base material around it. The shape formed by the inner peripheral surface of the concave portion 4 is configured to follow the shape formed by the outer peripheral surface of the titanium alloy plate 1, and an assembly between the inner peripheral surface of the concave portion 4 and the outer peripheral surface of the titanium alloy plate 1 is performed. A slight gap is provided in consideration of the flexibility and the deformation during forging.

  FIG. 2 shows another embodiment of the mold fixing device. FIG. 2A is a plan view of the mold fixing device seen from the up-down direction (z direction), and FIG. 2B is an xz sectional view taken along the line BB in FIG. 2A. The mold fixing device 200 shown in FIG. 2 differs from the embodiment shown in FIG. 1 in that the titanium alloy plate 3 is composed of a plurality of individual pieces. The rest of the configuration is the same as that of the embodiment shown in FIG. The titanium alloy plate 3 of the mold fixing device 200 shown in FIG. 2 is composed of two pieces each having a quadrangular main surface, but the number of pieces is not limited to this. By adopting a split type titanium alloy plate in which the titanium alloy plate is composed of two or more pieces, it is possible to reduce the size of each titanium alloy plate, and to reduce the load and cost required for producing the titanium alloy plate.

  FIG. 3 shows another embodiment of the mold fixing device. 3A is a plan view of the mold fixing device seen from the up-down direction (z direction), FIG. 3B is an xz sectional view taken along the line CC of FIG. 3A, and FIG. ) Is an exploded view seen from the same sectional view as FIG. In the mold fixing device 300 shown in FIG. 3, the heat insulating material 5 having a lower thermal conductivity than that of the titanium alloy is arranged in a part between the titanium alloy plate 3 and the base material 4 as shown in FIG. Different from the form. In addition, in FIG. 3A, the position of the heat insulating material 5 partially arranged on the lower side of the titanium alloy plate 3 is shown by a dotted line for convenience. By disposing the heat insulating material 5 having a lower thermal conductivity than the titanium alloy between the titanium alloy plate 3 and the base material 4, it is possible to enhance the heat insulating property and further reduce the heat escaping to the base material 4. The thickness (dimension in the z direction) of the heat insulating material is not particularly limited, but from the viewpoint of higher heat insulating property and easy handling, it is preferably thick, for example, 1 mm or more. On the other hand, if the thickness is too thick, the material cost of the heat insulating material increases and the formation of the recess for accommodating the heat insulating material becomes complicated. In the mold fixing device 300 shown in FIG. 3, a recess 7 for disposing the heat insulating material 5 is further provided at the bottom of the recess 6 of the base material 4, and the heat insulating material 5 is accommodated in the recess 7. . The fitting between the heat insulating material 5 and the recess 7 is accommodated by light press-fitting. According to such a configuration, since the outer periphery of the heat insulating material 5 is surrounded by the base material 4, even when a heat insulating material whose strength is lower than that of the titanium alloy plate is used, it is possible to prevent the strength of the heat insulating material from being an obstacle. .

In the mold apparatus 300 shown in FIG. 3, it is assumed that a mold having a circular outer shape is fixed, and it is sufficient to dispose the heat insulating material 5 within the mounting range of the mold, and therefore the heat insulating material 5 The outer shape of is shaped like a circle following the outer shape of the mold to be fixed. Further, the heat insulating material 5 can be configured integrally, but by adopting a split type heat insulating material in which the heat insulating material 5 is composed of two or more pieces, the assembling property of the heat insulating material 5 is improved and the cost is reduced. It is possible. In the mold device 300 shown in FIG. 3, the heat insulating material 5 has an annular shape as a whole. The heat insulating material 5 is composed of a plurality of fan-shaped pieces that are closely arranged in the circumferential direction.
Furthermore, FIG. 4 shows a modified example of the mold apparatus shown in FIG. FIG. 4 is a plan view of the mold fixing device seen from the up-down direction (z direction). The base material 9 of the mold fixing device 400 shown in FIG. 4 has a through hole 10 for a knockout pin for taking out the forging material after the hot forging is completed. Further, in the two titanium alloy plates 8 as well, a semicircular cutout is provided at a position corresponding to the through hole 10, and the through holes are also formed in the titanium alloy plate by arranging these cutouts in parallel. Rather than providing through holes in one titanium alloy plate, it is easier to manufacture the through hole parts by facing the notches provided in multiple titanium alloy plates, and it is also advantageous in cost reduction. .

A method for manufacturing a forged product to which the above-mentioned mold fixing device is applied will be described below.
An example of such a method for manufacturing a forged product is a method for manufacturing a forged product in which a heated forging material is hot forged by a die, and includes a first step of heating the die and fixing it to a die fixing device. The method includes a second step of placing the heated forging material on the die, and a third step of pressing down the forging material with the die. A forged product is obtained through the third step and further appropriate processing. The mold fixing device used in the first step has a titanium alloy plate arranged on a surface in contact with the mold, and a base material made of hot mold steel for supporting the titanium alloy plate. According to such a method for manufacturing a forging material, in hot forging using a heated die, both suppression of die temperature decrease and forging under a large load can be achieved. By disposing a heat insulating material having a lower thermal conductivity than the titanium alloy in a part between the titanium alloy plate and the base material, it is possible to more reliably suppress the mold temperature decrease. The specific structure and advantages of the mold fixing device are as described above, and thus the description thereof is omitted.

  FIG. 5 is a schematic configuration diagram of a press used in the method for manufacturing a forged product. The press machine 500 shown in FIG. 5 shows a state in which the first step of heating the molds 11 and 15 and fixing them to the mold fixing devices 12 and 16 has been completed. It should be noted that details such as the shapes of the mold surfaces 14 and 18 (carved surface) are omitted. The die 11 is a lower die, and the die 15 is an upper die, and these are paired to reduce the forging material. The mold fixing devices 12 and 16 to which the molds 11 and 15 are fixed are fixed to the press machine main bodies 13 (lower ram) and 17 (upper ram) using bolts and clamps, respectively.

Among the hot forgings, a particularly large hot pressing machine was used for the method for manufacturing the die fixing device and the forged product described above, which enables both suppression of the die temperature decrease and forging under a large load. The application to hot forging is suitable. For example, when a large hot press machine of 400 MN or more is used, a large product having a diameter of 1 m or more is suitable for hot forging and the like.
The forged product is a product manufactured through forging, such as a turbine disk and a turbine blade, and the forged material is a preform for obtaining a final forged product shape. The forging material includes not only the billet but also an intermediate material in the middle stage when performing hot forging a plurality of times (a plurality of blows). As the material of the forging material, for example, a Ni-base super heat resistant alloy, a Ti alloy, or the like can be used.

(Example)
A mold fixing device having the structure shown in FIG. 4 was produced. A Ti-5Al-4V (mass%) plate having a thickness of 25.4 mm was used as a titanium alloy plate, and SKT4 having a thickness of 200 mm was used as a base material. The thermal conductivity is 7.5 W / (m · K) for Ti-6Al-4V and 37 W / (m · K) for SKT4. The titanium alloy plate was housed in a recess provided in the base material and fixed with a bolt. A through hole was provided in the center of the base material. The titanium alloy plate was composed of two pieces each having a semicircular cutout, and the semicircular cutouts were arranged facing each other to form through holes corresponding to the through holes of the base material in the titanium alloy plate. Further, a glass resin heat insulating material Myorex PGX-595 (manufactured by Ryoden Kasei Co., Ltd.) having a thickness of 5 mm was arranged in an annular shape between the titanium alloy plate and the base material as a heat insulating material. Such a ring-shaped heat insulating material is formed by alternately arranging fan-shaped pieces of different sizes in the circumferential direction. The number of such pieces was six. The annular heat insulating material had an inner diameter of 400 mm and an outer diameter of 1300 mm.
A forged product was produced by hot forging as follows using the die fixing device. The mold was heated to 550 ° C. in a preheating furnace and fixed to the mold fixing device described above (first step). At this time, it was arranged so that the outer edge of the bottom surface of the mold was inside the outer edge of the titanium alloy plate. Further, after fixing the die fixing device to a pressing machine, a forging material nickel base super heat resistant alloy (Alloy 718) having an outer diameter of φ1000 mm heated to 1000 ° C. was placed on the die (second step). After that, the press machine was operated and the forging material was pressed down by the die to obtain a disc-shaped forged product having an outer diameter of φ1300 mm (third step). The forging load required for the reduction was 500 MN.

  FIG. 6 shows the results of measuring the temperature transition in a state where the mold was taken out from the preheating furnace and fixed to the mold fixing device. The temperature decrease from the heating temperature was suppressed more than before, and was within 40 ° C. after 30 minutes and within 60 ° C. after 60 minutes, which was a sufficient level even considering the setup time for fixing the mold. Further, even after the completion of forging, no defect such as breakage was found in the mold fixing device. From these results, it has been found that the mold fixing device and the method for manufacturing a forged product according to the embodiment make it possible to suppress the decrease in the mold temperature and to forge under a large load.

1: Titanium alloy plate 2: Base material 3: Titanium alloy plate 4: Base material 5: Heat insulating material 6: Recess 7: Recess 8: Titanium alloy plate 9: Base material 10: Through hole 11: Mold 12: Mold fixing Device 13: Press machine body (lower ram)
14: Mold surface (molded surface)
15: Mold 16: Mold fixing device 17: Press machine body (lower ram)
18: Mold surface (carved surface)
100, 200, 300, 400: Mold fixing device 500: Press machine

Claims (4)

A mold fixing device for fixing a heated mold,
A titanium alloy plate disposed on a surface in contact with the mold, the titanium alloy plate is perforated and a substrate made of hot die steel for supporting the one between the substrate and the titanium alloy plate A mold fixing device in which a heat insulating material having a lower thermal conductivity than that of the titanium alloy plate is disposed in a portion .   The mold fixing device according to claim 1, wherein the titanium alloy plate is arranged in a recess provided in the base material.   The mold fixing device according to claim 1, wherein the titanium alloy plate is composed of a plurality of pieces. A method of manufacturing a forged product in which a heated forging material is hot forged with a die,
A first step of heating the mold to fix it to a mold fixing device;
A second step of placing the heated forging material on the die,
A third step of rolling down the forging material by the die,
Wherein the mold fixation device comprises a titanium alloy plate disposed on a surface in contact with the mold, the have a titanium alloy plate made of hot die steel for supporting the substrate, and the titanium alloy plate A method for producing a forged product, in which a heat insulating material having a lower thermal conductivity than the titanium alloy plate is arranged in a part between the base material and the titanium alloy plate .