JPH0262349B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is particularly applicable to uniform control of mold temperature distribution in superplastic forging or isothermal forging in which the mold temperature is maintained at or near the material temperature. The present invention relates to a heating control method and device for a forging die for measuring .

(Conventional technology) Superplastic forging and isothermal forging technologies for difficult-to-work materials such as Ni-based alloys and Ti alloys utilize the superplastic behavior that occurs in those materials at specific temperatures and strain rates for forging. However, this superplastic deformation behavior is sensitive to the strain rate as well as the deformation temperature, and therefore, it is necessary to maintain a uniform temperature distribution of the material in order to allow the material to flow uniformly within the mold. Therefore, it is important to uniformly control the temperature distribution of the mold.

By the way, conventionally, the structure of the induction heating device used for heating the mold, the mounting structure of the heating coil, and the heating control method mainly depend on the shape of the forged product,
That is, although various methods are adopted depending on the structure of the forging die, a fixed method is generally used for attaching the heating coil to the die device.

Figures 3 and 4 show examples of the structure and mounting manner of such conventional heating coils. The structure of the heating coil and its mounting manner are shown. That is, in this illustrated example, the upper and lower bases 4,
The heating coil is divided into upper and lower parts of the upper heating coil 1 and the lower heating coil 1' corresponding to the upper and lower molds 2 and 3 attached to the upper and lower molds 5, and is fixed to the upper and lower molds 2 and 3, respectively.

According to this method, each upper and lower heating coil 1, 1'
Each is controlled independently, but since the heating coil is fixedly attached to the mold, the heating source position is fixed, so it is possible to control mold temperature fluctuations and temperature gradients that occur during forging. It is difficult to correct this, and it is difficult to maintain uniform heating of the heating material M.

On the other hand, for forged products with ribs on the outer periphery, a mold 7 consisting of upper and lower punches as shown in FIG.
A mold device consisting of three molds, a mold 8 and a female mold 9, is used. In such a case, the heating coil 1 can be a single coil type, but the heating coil Conventionally, the mounting method has been to fix it to the base 5 via the pillar 10 by suspending it from the top or supporting it from the bottom.

However, in such a system, the heating coil 1 is fixedly attached to the lower base 5, and the third
As shown in the figure, the mold heating position is necessarily fixed at a specific position. Therefore, when a temperature gradient occurs in the mold due to heat conduction in the upper and lower mold directions, and in particular, as the forging process progresses, the upper mold position is relatively displaced and the area overlaps with the coil effective heating zone l. If the temperature distribution of the upper mold changes due to a change in the temperature, it becomes difficult to control the temperature of the mold with this fixing method, which does not have a means for controlling the effective heating area of the coil.

On the other hand, if the heating coil 1 is fixed to the upper base plate 4, a problem will arise in the temperature distribution on the lower mold 8 side, contrary to the above.

(Problems to be Solved by the Invention) As mentioned above, in the conventional mold heating method in which the heating coil is fixed, the position of the effective heating zone of the coil is fixed at a specific position within the mold device, making it difficult to forge. Since this position cannot be changed during forging, it is not possible to adjust the temperature gradient within the die caused by heat conduction between the dies and the variation in die temperature due to changes in the overlapping area of the effective heating zone as forging progresses. It is difficult to maintain uniform mold temperature distribution.

The reason for the difficulty in conventional heating control is that the effective heating zone of the heating coil is fixed at a specific position within the mold device, and it is difficult to control the temperature of the mold. This is due to the lack of effective modification of the heating device configuration and control means.

Thus, the present invention has focused on the above points, fixed the position of the effective heating zone of the heating coil, and changed the width and position of the effective heating zone even during forging, independently of the displacement of the ram of the press, etc. Another object of the present invention is to provide a heating device and a control method that can be dynamically adjusted.

(Means for Solving the Problems) That is, the feature of the present invention that meets the above objective is that a heating coil is arranged around the outer periphery of the mold device system, and the mold temperature is made equal to or close to the material temperature. In superplastic forging or isothermal forging, in which forging is performed while maintaining the temperature, the position and/or width of the effective heating zone of the heating coil can be changed, and a temperature measuring element is installed in the mold, and the mold temperature is monitored by the temperature measuring element. However, the purpose is to uniformly control the mold temperature distribution by changing the position and/or width of the effective heating zone of the heating coil as the forging process progresses.

Here, as a specific means for changing the position of the effective heating zone of the heating coil, the heating coil is supported by a column having an elevating mechanism, and by driving the elevating mechanism, it is moved up and down as the forging process progresses. Therefore, a device is used in which the heating coil is supported so that it can be moved up and down.

In addition, a specific means for changing the width of the effective heating zone of the heating coil is to switch the coil taps, and for this purpose a device equipped with a coil tap changer for controlling the width of the effective heating zone of the coil is used. It will be done.

Furthermore, although the position and width of the effective heating zone of the heating coil may be changed only in either one, it is also preferable to combine both, and for this purpose, the apparatus is configured to have both of the above structures.

In either case, the effective heating zone is dynamically controlled while monitoring the mold temperature during the forging process to achieve uniform control of the mold temperature distribution.

(Function) According to the present invention, even if the mold temperature fluctuates as the forging process progresses, the effective heating zone can be adjusted by driving the lifting device and switching the coil tap while monitoring the fluctuation with the temperature measuring element. at any time,
By adjusting, it is possible to dynamically make the mold temperature distribution uniform.

(Examples) Hereinafter, specific embodiments of the method of the present invention will be further described in detail together with examples of the apparatus used in the examples.

FIG. 1 shows an example of an apparatus for carrying out the method of the present invention, in which 1 is a heating coil, 2 is an upper base plate 4
The upper mold 3 is attached to the upper and lower molds 5, and the lower mold 3 is attached to the lower base 5. These have almost the same structure as the conventional example shown in FIG. , 3 are disposed on the outer periphery of the mold device system, and is supported so as to be able to rise and fall on a column 6 having an elevating mechanism (not shown) fixed on a lower base 5. Although not included, temperature measuring elements for monitoring are incorporated in the required locations of the upper and lower molds 2 and 3.

In this case, the heating coil 1 is not necessarily supported at the bottom, but may also be suspended from the top.

In addition, as a drive mechanism for raising and lowering, although not particularly shown in the figure, electric type, hydraulic cylinder, air cylinder, inert gas cylinder, etc. can be used, and it can be easily designed using known methods. be.

Appropriate systems are selected for the lifting mechanism and the heating coil support means, taking into consideration the space, environment, atmosphere, etc. around the mold.

Accordingly, in the heating coil raising and lowering method as described above, the heating coil 1 is lowered to the mold crack surface when the heating material M is carried in or the forged product M' is carried out during processing. When the mold is preheated or when forging is proceeding downward, the heating coil 1 is raised and lowered by the drive mechanism while being monitored by a temperature measuring element (not particularly shown) built into the mold, thereby increasing the effective heating zone of the coil 1. The temperature distribution of the mold is controlled to be uniform by changing the position of the mold.

Next, FIG. 2 shows another embodiment of the present invention, in which the upper and lower punches 7,
An example in which the present invention is applied to a mold device system consisting of three molds, a mold 8 and a female mold 9 will be shown.

According to this embodiment, the heating coil 1 is placed on the outer periphery of the female mold 9, and is attached to the lower base 5 while being supported by a column 6 having an elevating mechanism, as in FIG.

Although not particularly shown, this device is equipped with a coil tap changer for changing the width of the effective heating zone l of the heating coil, and by switching the coil tap changer, the effective heating zone width can be changed. ing.

In this case, as in the case described above, temperature measurement elements embedded in the mold equipment are used to monitor the fluctuations in mold temperature that occur as the gap between the upper and lower punches is large at the initial stage of forging and as the gap gradually becomes smaller as the forging descends. At the same time, it is possible to dynamically equalize the mold temperature distribution by adjusting the effective heating zone, that is, the effective heating area, of the heating coil 1 while driving the lifting device, switching the coil tap, or using both together. Can be done.

(Effects of the Invention) As described above, the present invention makes it possible to change the position and width of the effective heating zone of the heating coil, and changes it accordingly while monitoring the mold temperature as the forging process progresses. Conventionally, it was not possible to achieve a sufficiently uniform mold temperature distribution using a fixed type, but the position and width of the effective heating zone of the heating coil can be easily and dynamically adjusted. It is expected that the uniform temperature distribution in the mold will be achieved, and the material flow in the mold will be made uniform in superplastic forging or isothermal forging, making it possible to obtain a homogeneous forged product.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional schematic diagrams showing each example of the apparatus for carrying out the method of the present invention, with the left half showing the state when the heated material is brought in, and the right half showing the state at the final stage of forging. . Figures 3 and 4 are cross-sectional schematic diagrams showing examples of fixed heating coil heating devices according to the conventional method, and as above, the left half shows the state when the heating material is brought in;
The right half shows the state at the end of forging. 1...Heating coil, 2...Upper mold, 3...Lower mold,
4... Upper base, 5... Lower base, 6... Support column,
7... Upper mold, 8... Lower mold, 9... Female mold, M...
...heating material.

Claims (1)

[Claims] 1. In a superplastic forging method or isothermal forging method in which a heating coil is arranged around the outer periphery of a mold device system and forging is performed while maintaining the mold temperature at or near the material temperature, A temperature measuring element is incorporated in the temperature measuring element, and the position and/or width of the effective heating zone of the heating coil is changed as the forging process progresses while monitoring the mold temperature by the temperature measuring element to uniformly control the mold temperature distribution. A heating control method for a forging die, characterized by: 2. Claim 1 in which the position of the effective heating zone of the heating coil is changed by raising and lowering the position of the heating coil.
2. Method for controlling heating of a forging die described in Section 1. 3. A heating control method for a forging die according to claim 1, in which the width of the effective heating zone of the heating coil is changed by switching the coil tap as the forging process progresses. 4 In an induction heating device for a mold in superplastic forging or isothermal forging, in which a heating coil is arranged around the outer periphery of the mold device system and forging is performed while maintaining the mold temperature at or near the material temperature, the heating device is raised and lowered. 1. A heating control device for a forging die, characterized in that it is supported by a column having a mechanism and can be raised and lowered by driving a lifting mechanism. 5 In an induction heating device for a mold in superplastic forging or isothermal forging in which a heating coil is arranged around the outer circumference of the mold device system and forging is performed while maintaining the mold temperature at or near the material temperature, the mold device system A coil tap changer that can change the width of the effective heating zone of the heating coil placed on the outer periphery is attached, making it possible to switch the coil tap while monitoring the mold temperature using a temperature measuring element built into the mold. A heating control device for a forging die, which is characterized by being tempered. 6 In an induction heating device for superplastic forging or isothermal forging, in which a heating coil is arranged around the outer periphery of the mold device system and forging is performed while maintaining the mold temperature at or near the material temperature, the heating coil is arranged around the outer periphery of the mold device system. The heated coil is supported by a column having an elevating mechanism, and can be raised and lowered by an elevating drive mechanism.The heating coil is also equipped with a coil tap changer that can change the width of the effective heating zone, and is incorporated into the mold. A heating control device for a forging die, characterized in that it is possible to raise and lower an effective heating zone of a heating coil while monitoring a temperature measuring element, and to change the width of the effective heating zone by switching coil taps.