JPS62238063A - Pressurizing impregnation apparatus for molten metal - Google Patents

Abstract

PURPOSE:To remove the damage of a reinforcing material in a complex material and to prevent the development of defects, such as casting blow hole, void, etc., by changing a pressurizing impregnation speed of a molten metal pressurizing plunger, using a pressurizing speed control means having plural steps, in accordance with the resistance of molten metal. CONSTITUTION:The speed of the molten metal pressurizing cylinder 12 is controlled by a proportional flow rate control valve 20. A setting voltage by a control C1 of a setting device 24 is converted into an electric current, and hydraulic oil at flow rate corresponding to low speed range is supplied to the pressurizing cylinder 12 through the proportional flow rate control valve 20. At the time of filling up the molten metal into the reinforcing fiber, an accelerating current is added through instruction by the control C2, and the flow rate of hydraulic oil is increased by the proportional flow rate control valve 20, to control at the high speed range. The pressure control sets the pressure in the low speed range through a relief valve 16 by operation of a solenoid selecting valve 15, and the pressure in the high speed range is set through a relief valve 17. The changing into the descent of the pressurizing plunger 11 is executed by a solenoid selecting valve 18 and this descendent speed is set by a speed controller 19.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is a method for pressurizing molten metal applied to a molding device for intermediate material (hereinafter referred to as billet) of fiber-reinforced metal composite material (hereinafter referred to as FRM). This relates to an impregnating device.

(Prior Art) In a conventional billet forming apparatus of this type, a whisker preform, for example, is inserted into a container, and a molten matrix metal is impregnated into the whisker preform under pressure to form a billet. However, the pressurization rate for this impregnation is usually constant.

Further, when fitting the container and the whisker preform, a very small gap was provided between the two in order to prevent center runout and the like.

By the way, if the pressurization rate during impregnation pressurization is constant as described above, in the initial stage of impregnation pressurization, the whisker preform may be damaged or the whisker itself may be broken due to the inertia of the matrix molten metal during impregnation pressurization. I often let them do it. In this state, when the matrix molten metal impregnates and flows into the voids of the spongy cake-like preform, the flow distribution becomes uneven, and as a result, the content (Vf) of the fiber reinforcement material in the matrix also becomes uneven, and at the same time, voids are formed. This has the drawback that defects such as cavities are more likely to occur.

(Problems to be Solved by the Invention) As described above, in the conventional billet forming apparatus of this type, the pressurizing speed when pressurizing and impregnating the matrix molten metal into the voids of the fiber preform is always constant. Therefore, damage to the preform or breakage of the fibers is likely to occur, especially at the initial stage of impregnation and pressure.As a result, the flow distribution of the molten matrix becomes uneven, the content of fibers in the matrix becomes uneven, and at the same time, voids occur. There was a problem in that it became easy to produce, resulting in a high number of defective products.

The present invention was developed in order to solve these problems, and it is possible to control the impregnation pressurization speed to follow a pattern that matches the resistance when passing through the spongy cake-like voids of the fiber preform. The present invention aims to provide a molten metal impregnation pressurizing device.

(Means for Solving the Problems) Therefore, the present invention provides an apparatus for impregnating a fiber preform with a molten matrix metal under pressure to form an FRM billet, by adjusting the impregnation pressurization rate of the molten metal pressurizing plunger. A molten metal pressurization impregnation device characterized by having a two-stage or multi-stage pressurization speed control means so as to impregnate the matrix metal at an impregnation speed pattern commensurate with the resistance of the molten metal passing through the voids of the fiber preform. The configuration is as follows:
This is a means to solve the above problem.

(Function) At the initial stage of molten metal impregnation, the pressurizing plunger is set at a low speed to fill the gap between the container and the fiber preform with the molten metal, and then the pressurizing speed is changed to a variable pressurizing speed required to impregnate the molten metal into the gap in the preform. Control. This variable speed control programs the required pressure and speed patterns to provide efficient control.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows the configuration of the pressurized molten metal impregnation apparatus according to this embodiment, in which the mold clamping cylinder 7 and the upper platen 8, the moving platen 9 and the mold clamping head 3, and the molten metal container 2 and the lower platen 10 are all integrated. There is a fiber container 1 between the mold clamping head 3 and the molten metal container.
A pressurizing plunger stem 11 connected to a piston of a molten metal pushing cylinder 12 is fitted into the molten metal container 2.

The upper platen 8 and the lower platen 10 are connected by a tie rod 13, and the lower platen 10 and the molten metal pushing cylinder 12 are connected by a strain rod 14, and at the same time, the moving platen 9 is connected to the tie rod 13.
and the fiber container 1 engage with each other.

Further, the mold clamping head 3 is provided with a deaeration port 26 for discharging the gas in the fiber container 1 before impregnation with molten metal.
A vacuum degassing valve 4 for maintaining the vacuum inside the fiber container 1 is integrated into the degassing chamber 26.

Here, in this embodiment, as shown in FIG. 2, the fiber container 1 has a tapered shape in which the inner diameter becomes slightly larger from a portion 475 to 3/4 from the lower end toward the lower end. .

In the above configuration, for example, the whisker preform 5 is inserted into the fiber container 1 in a state where it is floating about IM from the lower end, and after the matrix molten metal 6 is poured into the molten metal container 2 and the mold is clamped, the inside of the fiber container 1 is After degassing, the molten metal pushing cylinder 12 is operated to impregnate the whisker preform 5 with the matrix molten metal 6 and pressurize it. In the early stage of this impregnation, before impregnation into the gap of the whisker preform 5, the gap "a" formed between the fiber container 1 and the whisker preform 5 shown in FIG. 2 is filled with the molten metal.

During this time, the impregnation speed of the pressurized plunger is kept low,
Thereafter, the speed is increased to a required speed, and the molten metal pushing cylinder 12 is controlled to impregnate the whisker preform 5 with the matrix molten metal 6. At this time, the impregnating resistance becomes thick (as the pressure of the pressure plunger increases, the pressure sensor 2
1 (FIG. 4), a signal to reduce the amount of supplied oil is issued, the plunger speed is reduced, and the plunger is controlled so as to provide the optimum impregnation speed. An example of this control pattern is shown in FIG. Further, FIG. 4 shows an embodiment of the above-mentioned control circuit, and is a control circuit diagram for obtaining the control pattern of FIG. 3. Hereinafter, an example of two-stage control in a low speed region and a high speed region will be explained based on FIGS. 3 and 4.

The speed control of the molten metal pressurizing cylinder 12 is changed by the flow rate of pressure oil, and the same flow rate is controlled by the proportional flow control valve 20.
controlled by Further, the proportional flow rate control valve 20 is controlled by electric current. Now, a voltage setting corresponding to the low speed region is set on the setting device 24 using the knob C, and a voltage setting corresponding to the high speed region is set using the knob C2. Contact point 23 has two normally open switches S and S2.
is provided, and when the switch S is turned on, a command signal is issued by the knob C1, and the amplifier 25 converts the set voltage of the knob C1 into a current, which is then applied to the pressurizing cylinder 12 via the proportional flow control valve 20, corresponding to the low speed region. Supply pressure oil at a flow rate of Thereafter, after the timer 22 has elapsed for a predetermined time, that is, the time (1) required for the portion "a" shown in FIG. 2 to be filled with molten metal, the switch S! is turned ON, an acceleration current commensurate with the set value is added from the amplifier 25 in response to a command signal from the knob C2, and the pressure oil flow rate is increased by the proportional flow rate control valve 20 to be controlled in a high speed region.

In the conventional constant rate control method for impregnation, the inertia due to pressurization of the molten metal and the flow distribution of the molten metal, that is, the passage area is narrowed, so the impact at the initial stage of impregnation is large and the impregnation passage area is small, resulting in damage to the preform. However, according to this example, there was no damage to the preform, and the billet was not easily removed after molding.
The flow distribution during impregnation is improved and the impregnation rate of the fibers is also made uniform. Further, since the inner diameter portion of the fiber container 1 is tapered, knocking out of the molded product is facilitated, and the capacity of the knockout device is also advantageous.

On the other hand, pressure control at this time is performed by operating the electromagnetic switching valve 15, and by controlling the pressure setting in the low speed region with the relief valve 16.
Further, another relief valve 17 is used to set the pressure in the high-speed region for control. Note that the timing of switching from the low speed area to the high speed area is determined by the timer 22 as described above. Further, the pressurizing plunger stem 11 is operated by the molten metal pushing cylinder 12, but the switching operation of pressurizing and stopping the molten metal and lowering the pressurizing plunger stem 11 is performed by an electromagnetic switching valve 18, and the plunger stem 11 is determined by the setting of the speed controller 19.

(Effects of the Invention) As described above in detail, according to the present invention, damage to the reinforcing material fibers is prevented by impregnating the matrix molten metal from around the lower part of the fiber preform and by controlling the variable speed of the pressure plunger. Therefore, billets without defects such as casting voids can be formed. In addition, the desired impregnation rate pattern determined by the various materials of the reinforcement and matrix as well as the reinforcing material content (Vr) of the billet can be freely selected and a wide range of program control can be performed, which expands the use of the device and its applications. It turns out.

[Brief explanation of drawings]

Fig. 1 is an overall view of a pressurized molten metal impregnation device as an embodiment of the present invention, Fig. 2 is a detailed cross-sectional view of the fiber container portion of the same device, and Fig. 3 is a molten metal pressurized impregnation speed of the same device. FIG. 4 is a control circuit diagram of a pressurized molten metal impregnating apparatus as an embodiment of the present invention. Explanation of the main parts of the diagram 1... - Fiber container 2 - Molten metal container 5 - Whisker preform 6 - Matrix molten metal 7 - Clamping cylinder 11 - Pressure plunger stem 15.18 - Solenoid switching valve 16, 17 - Relief valve 20 - Proportional flow control valve 21 - Pressure detector 22 - Timer 23... Contact 24 - Setting device Patent applicant Mitsubishi Heavy Industries, Ltd. Figure 1 Figure 2

Claims (1)

[Claims] In an apparatus for pressurizing and impregnating a fiber preform with a molten matrix metal to form an intermediate material of a fiber-reinforced metal composite material, the impregnation pressure speed of the molten metal pressurizing plunger is adjusted to the impregnating pressure rate of the molten metal that passes through the voids of the fiber preform. A molten metal pressurization impregnation apparatus characterized by having a two-stage or multi-stage pressurization speed control means so as to impregnate the matrix metal with an impregnation speed pattern commensurate with the resistance of the molten metal.