JPH069723B2 - Constant temperature forging method and device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a constant temperature forging method and apparatus, and is used for forging a long material such as a marine blade.

(Prior art) Superplastic forging or isothermal forging as a technique for forging difficult-to-process materials such as Ti and Ni-based alloys while maintaining the forging die temperature and the forging material temperature at about the same level. There is.

In the above technique, it is necessary to heat the forging die,
Therefore, the induction heating method shown in FIGS. 6 and 7 is adopted.

In FIG. 6 and FIG. 7, the upper support mold 107 is attached to the heat insulating board 104.
The upper die 102 for forging is provided through, the lower support die 106 is provided with the forging die 101 through the heat insulating plate 105, and the lower debt 101 is provided in the illustrated example, and the illustrated example is also provided. Then, the insert die 103 is provided in the lower die 101 via the knockout rod 109 for taking out the product, so that the forged product 110 is formed.

In this device, the heating coil 111 in the induction heating device for heating the mold is arranged in a surrounding shape around the outer periphery of the mold as shown, while maintaining the mold temperature at about the same as the forging material temperature while heating. As the forging operation proceeds, the width and position of the effective heating zone of the heating coil 111 can be dynamically and independently adjusted to ensure uniform distribution of the mold portal material.

(Problems to be Solved by the Invention) The induction heating method described above has problems in the following points. That is, in the induction heating method, due to the restriction of the heating principle, the target mold can be used only for a circular mold as viewed from the pressing direction. Therefore, it is not applicable to heating a die having a rectangular shape, for example, for forging a rectangular or long product.

Also, in this heating method, because of the structure, heating is concentrated only on the outer periphery of the mold, and the temperature inside the mold is raised by the thermal conductivity of the mold material, so a Ni-based alloy with a low thermal conductivity is used. When the above is used as a mold material, the temperature difference between the inner and outer peripheral parts becomes large, which leads to the occurrence of thermal stress and, in extreme cases, damage to the mold.

In order to avoid the above-mentioned defects, if a means for preheating the mold is taken, long-time heating is required to reach the desired temperature, for example, 900 ° C. Furthermore, in this method, since the heat supply is always limited to the outer peripheral portion,
It is difficult to control the mold temperature substantially uniformly, and it is necessary to develop a heating structure having a plurality of heating zones in order to deal with the difficulty of soaking control in the induction heating method.

The cause of the above-mentioned induction heating is limited to a circular die, and the uniform heating control is difficult because it is due to the heating principle of the same method, and in order to overcome such restrictions and difficulties. Is a mold heating method that uses a heating principle different from the induction heating principle, and that can control the temperature of multiple heating sources independently of each other, or individually for each zone. is necessary.

Therefore, the applicant of the present invention has proposed a constant temperature forging technique (not a known technique) shown in FIG. 5 on the same date.

In FIG. 5, as the lower die 2 and the upper die 3 made of Ni alloy, the outer side shapes are made rectangular when viewed from the pressing direction, and both dies 2 and 3 are heated to about 900 ° C. As a holding member, a lower mold bottom heater plate 8 and an upper mold bottom heater plate 9 are provided on the opposite surfaces of the molds 2 and 3 from the mating surfaces, and the outer mold surfaces are also respectively provided. Lower mold side heater plate 11 and upper mold side heater plate 12
Is provided.

At this time, each heater plate 8, 9, 11, 12 is separated,
Separated, bottom heater plate 8, 9
In the above, a rod-shaped resistance wire heating body 10 is used, and in the side heater plates 11 and 12, a plane resistance wire heating body 13 is used. . Further, since the forging load acts on the heater plates 8 and 9 for the bottom surface, the plate material is a member having strength even at a temperature of 900 ° C., for example, a heat resistant material made of Ni-based alloy is used.

In addition, as an overall structure, heat insulating plates 4 and 5 made of refractory bricks or fine ceramics are attached to the lower parts of the bottom heater plates 8 and 9 in order to improve heating efficiency and suppress heat transfer to the press side. In addition, by providing the lower supporting mold 6 and the upper supporting mold 7 that support the whole,
The entire mold is configured and each heater plate 8,
9 and 11 and 12 are separated and independent for each plate, and the temperature can be adjusted by zone control for each plate or for each plate.

The technique shown in FIG. 5 can solve the problems of the above-mentioned conventional technique (FIGS. 6 and 7) in that the molds 2, 3 and by extension, the forging material 1 can be heated to a uniform temperature.

However, when the material 1 to be forged is a long material having a long axis and a short axis, its deformation resistance acts to spread elastic deformation of the molds 2 and 3 and the press frame, resulting in defective dimensions. Remains.

That is, in the forging of a long material, the central portion is generally thick due to the bending deformation of the molds 2 and 3 and the press frame, which requires machining to finish the product dimension after forging. Of course, it is also a problem in terms of yield.

Also, molds 2, 3, heater plates 8, 9, 11, 12, heat insulating plates 4,5
Are in surface contact, so heat transfer between the three becomes easy,
The temperature of the heat insulating plates 4 and 5 rises to the same level as the molds 2 and 3.
Even if ceramics are used as the heat insulating plates 4 and 5, there is a limit to the load resistance at high temperature and there is a risk of damage, and in order to eliminate this, there is a constraint that it must be used at a temperature as low as possible. is there.

The present invention has been devised in view of the above-described problems, and when isostatically forging a long material to be forged, the flexural deformation of a die or the like that is about to flexurally deform due to the action of deformation resistance of the material is canceled out. After the forging process, the product is forged so that it can be used as it is without machining, to the final product shape (net shape)
It is possible to prevent the damage of the heat insulating plate by suppressing the temperature rise of the heat insulating plate.

(Means for Solving the Problem) The present invention is a plate-shaped heater plate 8 having resistance wire heating bodies 10 and 10 built-in on the surface opposite to the mating surfaces of a pair of constant temperature forging dies 2 and 3. 9 are arranged, heat insulating plates 4 and 5 are provided between each heater plate 8 and 9 and the pair of mold supporting plates 6 and 7, and have a long axis and a short axis inserted into the pair of molds 2 and 3. Forging 1
In the method of forging while heating the heater plates 8 and 9 as heating sources, the following technical means are taken to achieve the above-mentioned first object.

That is, according to the present invention, at least one of the heater plate 9 for the mold 3 and the heat insulating plate 5 has a width in the left-right direction along the major axis direction of the object 1 to be forged, and the central portion has a heater. The first feature is to insert and forge the intermediate plate 16 which is made to be a thick portion 16A by being bulged toward the plate 9 and made of the same material as the die.

Further, according to the present invention, an intermediate plate 16 made of the same material as the mold is inserted between at least one of the heater plate 9 for the mold 3 and the heat insulating plate 5, and the intermediate plate 16 is the forging object. A second feature is that the first thick portion 16A has a width in the left-right direction along the long axis direction and the central portion thereof is protruded toward the heater plate 9.

(Examples and Actions) Hereinafter, examples and actions of the present invention will be described. The basic structure of the isothermal forging die device is basically the same as that described with reference to FIG. , Common parts are indicated by common symbols, and the improved parts are mainly described 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, 3, that is, made of Ni alloy, is inserted between and the thick plate whose central portion protrudes toward the heater plate 8 in the intermediate plate 14. An air layer 15 is formed on each of the left and right sides of the thick portion 14A.

Furthermore, between the upper heater plate 9 and the heat insulating plate 5,
An intermediate plate 16 made of a Ni alloy is inserted, and a thick portion 16 having a central portion protruding toward the heater plate 9 is inserted into the intermediate plate 16.
The air layer 17 is formed on both left and right sides of the thick portion 16A.

That is, the forged material 1 and its material 1A are a pair of molds
It is a long material that is inserted into the mold matching surfaces 2 and 3 and has a long axis and a short axis as shown by the material 1A in FIG. 4, and when the material 1A is inserted into the mold matching surface, the intermediate plate 14 , 16 is forging 1 (material 1
A) has a width in the left-right direction along the major axis direction, and the central portion is raised to form thick-walled portions 14A, 16A.

The forged material 1 and the material 1A are long materials such as a blade made of a Ti alloy (Ti-10V-2Fe-3Al) having a major axis of about 500 mm, and the molds 2 and 3 are The width of the material 1A corresponding to the short axis is 350 mm, and the length corresponding to the long axis is 800 mm, which is made of Ni alloy having a rectangular shape and a thickness of 240 mm when viewed from the pressing direction.

Referring to FIG. 2, when the forging material 1 (material 1A) described above is forged with a forging load of 1000 tons using the above-described molds 2 and 3, the distance from the forging center in the longitudinal direction, the center portion and the end portion. The difference in wall thickness between and is analyzed by elasticity by the finite element method, and the curve A shown in the figure is obtained.

This curve A does not need to be corrected, and the ridge or thick portion 14A,
The shape of 16A is determined, and the intermediate plates 14 and 16 manufactured based on this are illustrated in FIG.

In Fig. 3, the horizontal width of the material 1A along the lengthwise direction is 800m.
m, the front-rear width along the minor axis direction is 350 mm, the thickness is 50 mm including the thick-walled parts 14A, 16A, and the rectangular intermediate plates 14, 16 when viewed from the pressing direction
Has a protrusion height of 1.0 mm and a distance of 150 mm from each of the left and right edges, that is, the central portions 14A and 16A having a horizontal width of 500 mm along the long axis direction of the material 1A have a height of 0.15 mm. It has been raised.

The intermediate plates 14 and 16 compensate for the flexural deformation of the pair of molds 2 and 3, and the thick portions 14A and 16A are represented by parabolas or cosine curves.

However, since the pressure distribution acting on the die differs depending on the shape and material of the material to be forged and the processing conditions, the amount of deflection of the die also changes. Therefore, the pressure distribution is obtained by analysis by the finite element method, the amount of deflection of the die is obtained, and then the shape of the thick portion is determined.

According to forging using the intermediate plates 14 and 16 shown in FIG.
The air layers 15 and 17 are retained during forging on the left and right sides of the blade (material to be forged 1) to reduce the bending moment to the heater plates 8 and 9 and the dies 2 and 3, and the heater plate 8 It was clarified that the transfer of heat from the 9 and 9 to the heat insulating plates 4 and 5 was reduced as much as possible.

Specifically, in the technique of FIG. 5, the thickness of the forged material in the central portion is 0.2 mm thicker than both ends, whereas in the embodiment of the present invention, the thickness of 0.2 mm in the technique of FIG. It became 0.02 mm or less, and it was possible to cast a product with sufficient accuracy as the above net sharpening, and the yield was also improved.

Although not shown in the figure for temperature adjustment by the heater plates 8, 9, 11, and 12, while monitoring the temperature of each point inside the mold, the heater plates 8, 9, 11, and 12 are Performing constant temperature forging of the target blade while maintaining a uniform temperature of 900 ° C even under a forging load of, for example, about 1000 tons, by individually or individually controlling the heater plates 8, 9, 11, 12 for each zone. It was able to be completed without support.

Further, as the heater used for the side heater plates 11 and 12, a rod-shaped resistance wire heating body may be used instead of the planar resistance wire heating body 13.

Further, the intermediate plates 14 and 16 are preferably provided on both of the pair of molds 2 and 3, but may 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 first and second characteristics of the present invention, since the middle portion along the long axis direction of the material to be forged uses the thick intermediate plate, The bending deformation of the mold etc. is canceled out, and even if it is a long difficult-to-process material, net sharpening is possible and the yield is also improved.

In addition, inserting an intermediate plate having a thick portion in the center between the heater plate and the heat insulating plate means that an air layer is formed between the heater plate and the heat insulating plate, whereby the heat insulating plate is formed. The temperature rise is suppressed and there is no risk of damage.

[Brief description of drawings]

1 is an elevation sectional view of an embodiment according to the present invention, FIG. 2 is a graph for setting the shape of an intermediate plate, FIG. 3 is a perspective view of the intermediate plate, and FIG. 4 is a forged material or its material. FIG. 5 is an elevation sectional view of the proposed technique (comparative example), FIG. 6 is an elevation sectional view of a conventional example, and FIG. 7 is a plan sectional view of the same. 2 ... Lower mold, 3 ... Upper mold, 4,5 ... Insulation plate (panel), 8, 9, 11,
12 ... Heater plate, 14,16 ... Intermediate plate, 14A, 16A ... Thick part.

Claims (2)

[Claims] 1. A plate-shaped heater plate (8) (having a built-in resistance wire heating element (10) (10) on the surface opposite to the mating surfaces of a pair of constant temperature forging dies (2) (3). 9) is arranged and each heater plate (8)
(9) and a pair of mold support plate (6) (7) is a forged object having a long axis and a short axis inserted between the heater plate (8)
In the method of casting while heating (9) as a heating source, at least between the heater plate (9) and the heat insulating plate (5) for one of the molds (3), the forging object (1) An intermediate plate (16) having a width in the left-right direction along the long axis direction and having a central portion protruding toward the heater plate (9) to form a thick portion (16A) and made of the same material as the mold is used. A constant temperature forging method characterized by inserting and forging. 2. A plate-shaped heater plate (8) (9) having resistance wire heating bodies (10) (10) built in on the bottom surface opposite to the mating surfaces of a pair of constant temperature forging dies (2) (3). ) Is placed on each heater plate (8)
(9) and a pair of mold support plate (6) (7) between the heat insulating plate (4) (5) is provided, with a long shaft inserted between the pair of mold (2) (3) In a constant temperature casting apparatus for casting a forged object (1) having a short axis while heating the heater plates (8) and (9) as a heating source, at least one heater plate (9) for the mold (3) is used. ) And the heat insulating plate (5), an intermediate plate (16) made of the same material as the mold.
Thickness of the intermediate plate (16) having a width in the left-right direction along the long axis direction of the object to be forged (1) and having a central portion protruding toward the heater plate (9). A constant temperature forging device having a meat portion (16A).