JPH0377736A - Method and apparatus for isothermal forging - Google Patents

Abstract

PURPOSE:To remove the deflection of a die and a make a product net-sharp by inserting an intermediate plate having a central part projected toward a heater plate and composed of material of the same kind as the die between the heater plate for the upper die and a heat-insulating plate. CONSTITUTION:The intermediate plate 16 made from Ni alloy is inserted between the upper heater plate and the heat insulating plate 5 and this intermediate plate 16 is provided with a thick part 16A having its central part projected toward the heater plate 9 and an air layer 17 is formed on the outside of the thick part 16A. Consequently, the air layer is formed between the heater plate and the heat insulating plate, the heat insulating plate is restrained from rise of temperature and free from breakage.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a constant temperature forging method and apparatus, and is used for forging long materials such as marine blades.

(Prior art) As a technology for forging difficult-to-work materials such as Ti and Ni-based alloys while maintaining the temperature of the forging die and the temperature of the forging material at approximately the same level, the superplastic forging method or the isothermal forging method is used. be.

In the above technology, it is necessary to heat the forging die.
For this reason, the induction heating method shown in FIGS. 5 and 6 is employed.

In FIGS. 5 and 6, an upper forging die 102 is provided to an upper support die 107 via a heat insulating disk 104, and a lower forging die 101 is provided to a lower support die 106 via a heat insulating disk 105. An insert mold 103 is provided in the lower mold 101 on the open side via a knockout rod 109 for removing the product, so that a forged product 110 can be removed.
It is like molding.

In this device, a heating coil 111 in an induction heating device for heating the mold is arranged in an encircling manner around the outer periphery of the mold as shown in the figure, and maintains the mold temperature at approximately the same level as the forging material temperature. The forging operation proceeds, and at this time the width and position of the effective heating zone of the heating coil H1 are independently and dynamically adjustable to ensure uniform mold temperature distribution.

(Problems to be Solved by the Invention) The above-mentioned induction heating method has the following problems. That is, in the induction heating method, due to restrictions on its heating principle, the target mold can only be used for molds having an axially symmetrical shape. Therefore, it cannot be applied to heating a rectangular mold for forging rectangular or long products, for example.

In addition, with this heating method, heating is concentrated only on the outer periphery of the mold due to its structure, and the temperature inside the mold is raised by the thermal conductivity of the mold material, so Ni-based alloys with low thermal conductivity are heated. When used as a mold material, the temperature difference between the inner and outer circumferential parts becomes large, leading to the generation of thermal stress and, in extreme cases, mold breakage.

In order to avoid the above-mentioned defects, if a method of body heating the mold is used, a long period of heating is required to reach the desired temperature, for example, 900°C. Furthermore, in this method, the supply of heat is always limited to the outer periphery, so it is difficult to control the mold temperature substantially uniformly. requires the development of heating structures with multiple heating zones.

The reason why mold heating by induction heating is limited to circular molds and it is difficult to control uniform heating is due to the heating principle of this method, and in order to overcome these restrictions and difficulties, This requires a mold heating method that uses a heating principle different from the induction heating principle and uses a plurality of heating sources, and the temperature of each heating source can be controlled independently or zone by zone.

Therefore, the present applicant has previously proposed a constant temperature forging technique (not a known technique) as shown in FIG.

In FIG. 4, it is assumed that a rectangular lower mold 2 and a rectangular upper mold 3 made of Ni alloy are used, and both molds 2 and 3 are heated and maintained at approximately 900''C. Heater plate 8 for the bottom of the lower mold, heater plate 9 for the bottom of the upper mold.
In addition, a lower mold side surface heater plate 11 and an upper mold side surface heater plate 12 are also provided on each side surface.

At this time, each heater plate 8, 9, 11, 12 is separated and independent, and the bottom heater plate 8, 9 uses a sheathed resistance wire heater 10, and the side heater plate 1, In No. 12, a pad type resistance wire heater 13 is used, and both heaters 10 and 13 are built into the plate side.

Furthermore, since a forging load acts on the heater plate 8.9 for the bottom surface, the material of the plate is a member that has strength even at a temperature of 900'C, and is made of a heat-resistant material made of, for example, a Ni-based alloy.

In addition, as for the overall structure, at the bottom of each bottom heater plate 8.9, a cross-sectional plate (body) 4.
5 is attached, and a lower support mold 6 and an upper support mold 7 that support the whole are provided to constitute the entire mold, and each heater plate 8, 9 and II,
Reference numeral 12 indicates that each plate is separate and independent, and the temperature can be adjusted by zone control for each individual plate or a plurality of plates.

The technique shown in FIG. 4 can solve the problems of the prior art (FIG. 5.6) in that the molds 2, 3 and, by extension, the material to be forged 1 can be heated to a uniform temperature.

However, when the material to be forged I is a long material, the problem remains that its deformation resistance acts and affects the elastic deformation of the molds 2 and 3 and the press frame, resulting in dimensional defects.

In other words, when forging long materials, the central part generally becomes thicker due to the bending deformation of the dies 2 and 3 and the press frame, and this requires machining to achieve the product dimensions after forging, which increases the processing time. Of course, this also poses a problem in terms of yield.

In addition, molds 2, 3, heater plates 8, 9, 11, 12
Since the heat insulating plates 4 and 5 are in surface contact with each other, heat transfer between the three is facilitated, and the temperature of the insulating plates 4 and 5 rises to the same level as that of the molds 2 and 3. Even if ceramic is used as the heat insulating plate 4.5, there is a limit to its load resistance at high temperatures and there is a risk of damage, and in order to eliminate this, there is a restriction that it must be used at as low a temperature as possible. be.

The present invention was devised in view of the above-mentioned problems, and when a long forged material is isothermally forged, the deformation of the mold, etc., which tends to be deformed due to the deformation resistance of the core material, is canceled out. , enables the net sharpening of products, and
The first purpose is to suppress the temperature rise of the heat insulating board and prevent its damage.

Furthermore, a second object of the present invention is to achieve the above-mentioned first object while also ensuring uniform heating.

(Means for Solving the Problems) The present invention provides the upper and lower bottom surfaces of the upper and lower molds 2.3 for isothermal forging.
A plate-shaped heater plate 8.9 having a built-in resistance wire heating element 10.10 is disposed, and a heat insulating plate 4.5 is provided between each heater plate 89 and the upper and lower mold support plates 6.7. In the method of forging the to-be-forged object l charged into the dies 2 and 3 while heating it using the heater plate 8.9 as a heat source, the following technical means are used to achieve the above-mentioned first objective. I am teaching.

That is, the present invention provides at least a thick wall portion 16A with a central portion protruding toward the heater plate 9 between the heater plate 9 and the heat insulating plate 5 for the upper mold 3, and which is of the same type as the mold. The first feature is that the intermediate plate 16 made of material is inserted and forged.

Further, in the present invention, an intermediate plate 16 made of the same material as the mold is inserted between at least the heater plate 9 for the upper mold 3 and the heat insulating plate 5, and the intermediate plate 16 has a central portion that is heated by the heater. The second feature is that the thick portion 16A is protruded toward the plate 9.

Furthermore, in order to achieve the second object mentioned above, the present invention has the following features:
The upper and lower molds 2 and 3 have a non-axisymmetric shape such as a rectangle, and plate-shaped heater plates 11 and 12 are also arranged on each side of the molds 2 and 3, and heater plates 8 and 12 are arranged on the upper and lower bottom surfaces and on each side.
The third feature is that 9, 11, and 12 are each used as an independent heating source, and the heating temperature is controlled individually or zone by zone for forging.

(Embodiments and operations) Examples and operations of the present invention will be described below, but the basic configuration as a constant temperature forging die device is basically the same as that explained with reference to FIG. , common parts are indicated by common symbols, and improved parts will be mainly explained below.

As shown in FIG. 1, the lower heater plate 8 and the heat insulating plate 4
An intermediate plate 14 made of the same material as the molds 2 and 3, that is, a Ni alloy, is inserted between the metal molds 2 and 3, and this intermediate plate 14 has a thick wall with a protruding central portion toward the heater plate 8. Part 1
4A, where air 11 is placed on the outside of the thick part 14^.
15 is a formality.

Furthermore, between the upper heater plate 9 and the heat insulating plate 5,
An intermediate plate 16 made of Ni alloy is inserted, and the intermediate plate 16 has a thick wall portion 16A whose central portion protrudes toward the heater plate 9. On the outside of the thick wall portion 16A, An air layer 17 is formed.

The forged material 1 is a Ti alloy (T
It is a long material like a blade made of i-10V-2Fe-3AZ), and the mold 2.3 has a width of 350nw* and a length of 80nm.
It is made of Ni alloy with a thickness of 0 mm and a thickness of 240 nna.

Referring to FIG. 2, the distance in the longitudinal direction from the forging center and the wall thickness at the center and end portions when the forged material 1 described above is forged using the aforementioned dies 2 and 3 with a forging load of 1000 tons. The difference was elastically analyzed using the finite element method, resulting in curve A shown in the figure.

This curve A is, in other words, a protrusion, that is, a thick portion 14.
This determines the shape of A, 16^, and the intermediate plate 14.16 is illustrated in FIG. 3, which was manufactured based on this.

According to this, an air layer 15,17 is maintained outside the blade length of the blade (material 1 to be forged) even during forging, reducing the bending moment to the heater plates 8, 9 and the molds 2, 3. , heater plate 8.9 to insulation plate 4.5
It has become clear that the transfer of heat amount can be reduced as much as possible.

For example, in the technique shown in Fig. 4, the thickness of the forged material at the center is 0.2 mm thicker than at both ends, whereas in the embodiment of the present invention, 0.2+ma is 0.02 mm or less, and the net sharpness is It was possible to forge products with sufficient precision, and yields improved.

Although not shown in the figure, the temperature adjustment by the heater plate 8.9.11.12 is performed by monitoring the temperature at each point inside the mold and controlling it individually and zone by zone, for example. Even under a forging load of about 1000 tons, the isothermal forging of the target blade could be completed without any problems while maintaining a uniform temperature of 900'C.

Moreover, a sheath type resistance wire heater can also be used instead of the pad type resistance wire heater 13 as a heater used for the side heater plate 11.12.

Furthermore, although it is desirable to provide the intermediate plates 14 and 16 on the upper and lower sides, they may also be provided only on the upper mold or the lower mold.

(Effects of the Invention) The present invention is as described above, and according to the 1.2 feature of the present invention, since the intermediate plate with a thick center portion is used, the bending deformation of the mold etc. is canceled out. Even with long materials that are difficult to process, net sharpening is possible and yields are improved.

In addition, inserting an intermediate plate with a thick interior in the center between the heater plate and the heat insulating board means that an air layer is formed between the heater plate and the heat insulating board. Temperature rise is suppressed and there is no risk of damage.

Furthermore, according to the third feature of the present invention, in addition to the above-mentioned advantages, it is possible to uniformly heat the mold and, by extension, the material to be forged, even if the mold has a non-axisymmetric shape. Guarantees uniform temperature distribution outside.

[Brief explanation of drawings]

Fig. 1 is an elevational sectional view of an embodiment according to the present invention, Fig. 2 is a graph for setting the shape of the intermediate plate, Fig. 3 is a perspective view of the intermediate plate, and Fig. 4 is the proposed technology (comparative example). FIG. 5 is an elevational sectional view of the conventional example, and FIG. 6 is a plan sectional view of the conventional example. 2...Lower mold, 3...Upper mold, 4.5...Insulation board (board), 8.9.11.12...Heater plate, 1
4.16... Intermediate plate, 14A, 16A... Thick wall part.

Claims (3)

[Claims] (1) Plate-shaped heater plates (8) (9) containing resistance wire heating elements (10) (10) are arranged on the upper and lower bottom surfaces of the upper and lower molds (2) and (3) for isothermal forging, and each Heat insulating plates (4) (5) are provided between the heater plates (8) (9) and the upper and lower mold support plates (6) (7), and the materials charged into the upper and lower molds (2) (3) are The forged product (1) is attached to the heater plate (8).
In the method of forging while heating (9) as a heat source, at least the central part is located between the heater plate (9) for the upper mold (3) and the heat insulating plate (5).
A constant temperature forging method characterized by inserting and forging an intermediate plate (16) which is made of the same material as the mold and has a thick wall portion (16A) that is protruded toward the mold. (2) Plate-shaped heater plates (8) (9) containing resistance wire heating elements (10) (10) are arranged on the upper and lower bottom surfaces of the upper and lower molds (2) and (3) for isothermal forging, and each In a constant temperature forging device equipped with heat insulating plates (4) (5) between heater plates (8) (9) and upper and lower mold support plates (6) (7), at least An intermediate plate (1) made of the same material as the mold is placed between the heater plate (9) and the heat insulating plate (5).
6) is inserted, and the intermediate plate (16) has a thick portion (16) whose central portion is protruded toward the heater plate (9).
A) A constant temperature forging device characterized by having the following. (3) The upper and lower molds (2) and (3) have non-axisymmetric shapes such as rectangles, and plate-shaped heater plates (11 and 12) are arranged on each side of the molds (2 and 3). The forging is characterized in that the heater plates (8), (9), (11), and (12) on the upper and lower bottom surfaces and each side surface are used as independent heating sources, and the heating temperature is controlled individually or zone by zone. The constant temperature forging method according to claim (1).