JP2006263735A - Reduction-casting apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reduction-casting apparatus which enables sure reduction-casting by solving such problem that a supplying mechanism falls in defective operation because molten metal is intruded into the supplying mechanism for supplying a reducing material etc., when the reduction-casting operation is performed. <P>SOLUTION: The reduction-casting apparatus 10 for casting by filling up the molten metal 34 into a cavity 20a in a forming die 20 while reducing oxidized film on the surface of the molten metal by acting the reducing material to the molten metal in the case of filling up the molten metal 34 into the cavity 20a, is provided with a valve mechanism 50 for controlling the supplying movement of the reducing material, as a mechanism for supplying the reducing material, for acting the reducing material to the molten metal 34, wherein the valve mechanism 50 is provided with a rotary valve 51. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a reduction casting apparatus, and more particularly, to a reduction casting apparatus that activates and casts a reducing substance using thermal energy of a molten metal.

The reduction casting method is a method of reducing and casting an oxide film formed on the surface of the molten metal by causing a reducing substance to act on the molten metal. For example, an oxide film is formed on the surface of the molten metal like aluminum or an aluminum alloy. It can be suitably used for casting with a metal that is easily formed. In the reduction casting of aluminum using a magnesium nitrogen compound (Mg ₃ N ₂ ) as a reducing substance, the oxide film (Al ₂ O ₃ ) formed on the surface of the molten aluminum is reduced by the magnesium nitrogen compound, and the molten metal surface Becomes pure aluminum metal. According to this reduction casting method, the fluidity of the molten metal becomes extremely high, the hot water circulation property becomes good, and a high-quality cast product free from hot water wrinkles or the like can be obtained.

In the reduction casting method, in order to effectively reduce the oxide film formed on the surface of the molten metal, the reducing substance is activated as much as possible, that is, in a state where the reducing action is effectively applied to the molten metal. It is important to let For this reason, a method of arranging a heating furnace as close to the cavity as possible, generating a reducing substance in the heating furnace, and introducing the reducing substance into the cavity has been studied (see Patent Document 1).
JP 2002-28770 A

However, in order to install a heating furnace for heating the reducing substance close to the cavity, the configuration of the apparatus becomes complicated, and there is a problem that the layout of the mold and the heating furnace must be taken into account. There is a problem that it is not always an easy method to act on the molten metal in a sufficiently activated state.
In addition, in the reduction casting apparatus, a supply port for supplying carrier gas or a reducing substance is provided in a supply path for supplying molten metal to the cavity, and a control mechanism such as a seal plunger for controlling the supply operation of the reducing substance is provided in the supply port. However, in the case of a reduction casting device, casting is performed by applying a reducing substance to the molten metal, so that the fluidity of the molten metal is extremely good, and the molten metal easily enters the seal part of the control mechanism such as the seal plunger. There was a problem that the control mechanism malfunctioned.

  Therefore, the present invention has been made to solve these problems, and solves the problem that the molten metal enters the supply mechanism for supplying a reducing substance or the like during the reduction casting operation and the supply mechanism malfunctions. And it aims at providing the reduction casting apparatus which can perform reduction casting more reliably.

In order to achieve the above object, the present invention comprises the following arrangement.
That is, in a reduction casting apparatus that fills a cavity with a molten metal while casting the molten metal into the cavity of the mold and causes the reducing material to act on the molten metal while reducing the oxide film on the surface of the molten metal, the reducing substance is As a supply mechanism of the reducing substance that acts on the molten metal, a valve mechanism that controls the supply operation of the reducing substance is provided, and the valve mechanism includes a rotary valve.
Also, a reduction casting apparatus for casting by filling a mold cavity with a molten metal from a hot water tank, and receiving the heat of the molten metal in the hot water tank, the reducing substance or the reducing substance is applied to the hot water tank. An activation chamber for heating the metal to be produced is provided, and the valve mechanism is interposed in a flow path that communicates the activation chamber and the cavity.

The valve mechanism includes the rotary valve, a seal chip disposed in sliding contact with an outer peripheral surface of the rotary valve, the rotary valve, a position where the reducing substance is supplied, and a supply of the reducing substance. And a drive mechanism that rotates around the axis between the position where the valve is cut off.
In addition, the seal tip is provided so as to be constantly urged toward the outer peripheral surface of the rotary valve in the radial direction of the rotary valve.
In addition, the reducing valve or the rotary valve is caused by a spray nozzle action that is caused when a reactive gas that reacts with a carrier gas or a metal gas carrying the reducing substance to generate a reducing compound flows into the valve. A flow path for transferring the metal gas is provided.

  According to the reduction casting apparatus according to the present invention, since the rotary mechanism is used as the valve mechanism used in the supply mechanism of the reducing substance that acts on the molten metal, the sealing performance of the valve mechanism against the molten metal is improved. It is possible to eliminate malfunction of the mechanism and perform a reliable casting operation.

(Configuration of reduction casting equipment)
Hereinafter, preferred embodiments of a reduction casting apparatus according to the present invention will be described in detail with reference to the drawings.
FIG. 1 shows the overall configuration of an embodiment of a reduction casting apparatus according to the present invention. This reduction casting apparatus 10 is configured as a casting apparatus by LPD (low pressure die casting). The casting part of the reduction casting apparatus 10 includes a mold 20 and a hot water tank 30 installed below the mold 20, and a cavity 20 a and a hot water tank 30 provided in the mold 20 are provided in the hot water tank 30. The hot water supply pipe (Stokes) 32 is provided so as to communicate with each other. The hot water supply cylinder 32 is connected at its upper part to a feeder 22 provided in the mold 20, and the feeder 22 communicates with the cavity 20 a through a gate 23.

The hot water supply cylinder 32 is provided with the bottom portion extending to the bottom side of the hot water tank 30, and the hot water tank 30 is always immersed in the molten metal 34 stored in the hot water tank 30, along with the hot water supply pipe 32. The activation chamber 40 extended in this manner is arranged.
In the present embodiment, the activation chamber 40 is connected to the reducing substance supply unit 41 so that a reducing substance (for example, a magnesium nitrogen compound) is supplied to the activation chamber 40. A metal for generating a reducing substance in the activation chamber 40 by connecting a supply portion of a metal (for example, magnesium metal) for generating the reducing substance instead of the reducing substance to the activation chamber 40. Can also be configured to supply.
Inside the activation chamber 40, the reducing substance supplied to the activation chamber 40 is discharged from the supply pipe 42 before being fully activated, or the metal for generating the reducing substance is gasified. A buffer plate is provided to prevent discharge without being discharged.

The reducing substance accommodated in the activation chamber 40 is supplied to the cavity 20 a side of the mold 20 through the valve mechanism 50. In the present embodiment, a valve mechanism 50 using a rotary valve 51 is provided.
FIG. 2 shows an enlarged view of the valve mechanism 50. The rotary valve 51 has a cylindrical body provided with channels 51a, 51b, 51c that open on three sides of the outer peripheral surface. The flow paths 51a and 51c are linearly arranged in the radial direction, and the flow path 51b is provided in a direction orthogonal to the center of the flow path connecting the flow paths 51a and 51c. That is, the rotary valve 51 is formed with a flow path penetrating in the diameter direction and a flow path having a radius perpendicular to the flow path.

  On the outer periphery of the rotary valve 51, three seal chips 52a, 52b, and 52c that support the rotary valve 51 so as to be rotatable around an axis are disposed. In this embodiment, as a turning mechanism for turning the rotary valve 51 around one axis and the other side, one end of the lever 58 is fixed to the central axis of the rotary valve 51 and the other end of the lever 58 is fixed. A drive mechanism 59 such as an electric motor for rotating the lever 58 around the central axis is provided on the side.

  FIG. 3 shows an assembled perspective view of the rotary valve 51 and the three seal tips 52a, 52b, and 52c. The inner side surfaces of the seal tips 52 a, 52 b, and 52 c are formed into arcuate surfaces whose side surfaces have the same curvature as the outer peripheral surface of the rotary valve 51. The seal tips 52a, 52b, and 52c are provided with communication channels 53a, 53b, and 53c in an arrangement that communicates with the channels 51a, 51b, and 51c provided in the rotary valve 51 at the same time. The communication flow path 53c provided in the seal chip 52c is a tapered hole that gradually increases in diameter on the mold 20 side. The communication channel 53 c provided in the seal tip 52 c communicates with the feeder part 22 provided in the mold 20.

  The two seal tips 52 a and 52 b are supported by a guide body 54 fixed to the side surface of the mold 20 so as to be movable in the radial direction of the rotary valve 51. As shown in FIG. 2, the seal tip 52 a is always urged and supported by the spring 55 toward the rotary valve 51, and the seal tip 52 b is always urged and supported by the spring 43 toward the rotary valve 51. ing.

The guide body 54 supports a connection pipe 56 connected to the nitrogen gas supply part 57 via a pipe and a valve, and an end of the connection pipe 56 is air-sealed and slid into the communication channel 53a of the seal chip 52a. The In addition, the supply pipe 42 provided in the activation chamber 40 is slid into the communication channel 53b of the seal chip 52b with its tip end being air-sealed.
In the present embodiment, the spring 43 and the spring 55 are disposed so as to be extrapolated to the supply pipe 42 and the connection pipe 56, but the method of biasing the seal tips 52a and 52b is limited to the method of the present embodiment. It is not a thing.

(Reduction casting method)
Next, a method of using the above-described reduction casting apparatus 10 for aluminum casting will be described.
FIG. 1 shows a state before the molding die 20 is set in a hot water supply cylinder 32 provided in the hot water tank 30 and the molten metal 34 is filled in the cavity 20a. The valve mechanism 50 is set so that the rotary valve 51 turns off the communication between the feeder 22 and the activation chamber 40 by the drive mechanism 59.
In this state, a magnesium nitrogen compound is supplied from the reducing substance supply unit 41 to the activation chamber 40. An aluminum hot water furnace (not shown) is provided in communication with the hot water tank 30, and from the hot water furnace to the hot water tank 30 so that the liquid level of the molten metal 34 in the hot water tank 30 becomes a constant height in accordance with the casting operation. Aluminum melt 34 is replenished.

In the hot water tank 30, the molten aluminum is heated to about 740 ° C. Therefore, the magnesium nitrogen compound which is a reducing substance supplied to the activation chamber 40 is heated by the heat of the molten metal 34 and becomes activated.
In the case of supplying magnesium powder to the activation chamber 40 instead of supplying the magnesium nitrogen compound to the activation chamber 40, the melting point of magnesium is 651 ° C., so that the magnesium metal is heated by the heat of the molten aluminum. It is easily gasified.

  The operation of supplying the magnesium nitrogen compound to the activation chamber 40 is not an operation performed for each casting operation, but a plurality of casting operations can be performed by supplying a predetermined amount of the magnesium nitrogen compound to the activation chamber 40. Therefore, the magnesium nitrogen compound may be supplied every time a predetermined number of casting operations are performed. By supplying the magnesium nitrogen compound to the activation chamber 40 and elapse of a certain time, the magnesium nitrogen compound becomes sufficiently activated.

After setting the mold 20 in the hot water supply cylinder 32, the vacuum pump 24 is driven to depressurize the cavity 20a in order to make the inside of the cavity 20a non-oxidizing atmosphere.
FIG. 4 shows a state in which the inside of the cavity 20 a is depressurized, and then the valve mechanism 50 is opened to introduce the magnesium nitrogen compound from the activation chamber 40 into the feeder 22. The lever 58 is rotated by the drive mechanism 59 so that the flow paths 51a, 51b, 51c of the rotary valve 51 are made to coincide with the communication flow paths 53a, 53b, 53c provided in the seal tips 52a, 52b, 52c. As a result, the activation chamber 40 disposed on the hot water tank 30 side communicates with the hot water supply section 22 provided in the mold 20 via the valve mechanism 50.

Nitrogen gas is fed into the flow path 51 a of the rotary valve 51 from the nitrogen gas supply unit 57 through the connection pipe 56 in a state where the activation chamber 40 and the hot water supply unit 22 communicate with each other through the valve mechanism 50. . Since the flow paths 51a and 51c are linearly arranged, and the flow path 51b communicating with the activation chamber 40 is provided in the flow path, the flow path 51a is generated by flowing nitrogen gas through the flow path. The magnesium nitrogen compound is drawn out from the activation chamber 40 by the action of the spray nozzle, and the magnesium nitrogen compound is introduced into the hot-water supply unit 22 together with the nitrogen gas.
In this operation, nitrogen gas acts as a carrier gas for transferring a magnesium nitrogen compound as a reducing substance. As the carrier gas, a gas that does not impair the reducing action of the reducing substance, such as an inert gas, can be used instead of the nitrogen gas.

  A part of the magnesium nitrogen compound introduced into the feeder 22 diffuses from the feeder 22 to the upper side of the hot water supply cylinder 32, and a part diffuses from the feeder 22 into the cavity 20 a of the mold 20. Since the pressure in the upper space of the cavity 20a, the hot water supply section 22, and the hot water supply cylinder 32 is reduced in advance, the reducing action is reduced by the air in which the magnesium nitrogen compound diffused into the cavity 20a and the like remains in these spaces. There is no.

  When magnesium metal (powder) is supplied to the activation chamber 40 for reduction casting, the magnesium metal is gasified in the activation chamber 40 and nitrogen gas is allowed to flow into the valve mechanism 50 from the nitrogen gas supply unit 57. The magnesium nitrogen compound may be generated by reacting with the magnesium gas drawn out of the activation chamber 40 by the nitrogen gas, and the magnesium nitrogen compound may be sent to the feeder section 22 side. In this case, the gas fed into the valve mechanism 50 is a reactive gas (in this case, nitrogen in this case) that reacts with a metal gas (in this case, magnesium gas) to produce a reducing substance (in this case, a magnesium nitrogen compound). Gas) must be used. The reactive gas reacts with the metal gas to generate a reducing substance, and also serves as a carrier gas for conveying the reducing substance to the feeder 22.

  FIG. 5 shows a state in which after the magnesium nitrogen compound is introduced into the cavity 20a and the like, the valve mechanism 50 is closed and the cavity 20a is filled with molten aluminum from the hot water tank 30. By supplying pressurized gas (such as nitrogen gas) from the pressurized gas supply unit 33 provided in communication with the hot water tank 30 to the hot water tank 30 via the pipe 35, the molten metal is heated in the hot water tank 30. The liquid level of 34 is pushed down, the molten metal 34 is injected from the hot water supply cylinder 32 into the hot metal portion 22, and the molten metal 34 is filled into the cavity 20 a from the gate 23.

  Since the magnesium nitrogen compound is diffused and supplied to the hot water supply cylinder 32, the oxide film on the surface of the molten aluminum 34 is reduced when the molten metal 34 is pushed up from the hot water supply pipe 32 to the hot water supply section 22. Also in the hot water 22, the oxide film formed on the surface of the molten aluminum 34 is reduced by the magnesium nitrogen compound, so that the molten aluminum is poured into the cavity 20 a in an extremely easy to flow state.

  Further, since the magnesium nitrogen compound is diffused in the cavity 20a, the oxide film formed on the surface of the molten aluminum 34 when the molten metal 34 is filled in the cavity 20a is reduced, and the inside of the cavity 20a is reduced. Also, the molten metal 34 is filled in a state where the hot water surrounding property is very good. After the molten metal 34 is solidified in the cavity 20a, the mold is opened and the cast product is taken out.

According to the casting method of the present embodiment, the hot water circulation property in the cavity 20a and the like is improved, and a high-quality cast product free from molten metal filling and voids can be obtained.
In particular, in the present embodiment, the magnesium nitrogen compound is supplied directly from the activation chamber 40 disposed in the hot water tank 30 to the feeder 22 and the supply channel for the magnesium nitrogen compound is shortened. It becomes possible to supply the magnesium nitrogen compound to the feeder 22 and the like while reliably maintaining the activated state of the compound. As a result, the reduction action of the magnesium nitrogen compound can be effectively applied to the molten metal 34 for reduction casting.

In the casting method of the present embodiment, the valve mechanism 50 that supplies the reducing compound from the activation chamber 40 to the feeder section 22 side is configured using the rotary valve 51, so that the sliding portion of the valve mechanism 50 is The sealing performance can be improved, and the molten metal 34 can be prevented from entering the seal portion of the valve mechanism 50. The slidable contact surfaces of the rotary valve 51 and the seal tips 52a, 52b, 52c are both formed as arcuate surfaces, so that the rotary valve 51 and the seal tips 52a, 52b, 52c are sealed regardless of the rotational position of the rotary valve 51. Sex is reliably maintained.
In the present embodiment, the sealing tips 52a and 52b are always pressed against the rotary valve 51 using the biasing force of the springs 55 and 43, so that the sealing action when the rotary valve 51 rotates is achieved. Furthermore, it can hold | maintain reliably.

In the case of the reduction casting method, the fluidity of the molten metal becomes very good, and the molten metal easily enters the gap portion of the seal portion. However, the valve mechanism 50 using the rotary valve 51 is used as in the casting apparatus of the present embodiment. According to the method to be used, even when the fluidity of the molten metal is improved, it is possible to suitably prevent the molten metal from entering the seal portion, thereby making it possible to perform a reliable casting operation.
The valve mechanism using the rotary valve 51 can be similarly used as a valve mechanism for supplying reducing materials to the cavity in a reduction casting apparatus such as gravity casting in addition to the above-described reduction casting apparatus using the LPD method. It is.

  In the above embodiment, an example in which the reduction casting apparatus 10 is used for aluminum casting has been described. However, the reduction casting apparatus according to the present invention is not limited to casting aluminum or an aluminum alloy, but also for casting with a metal other than aluminum. It is possible to apply similarly.

It is explanatory drawing which shows the whole structure of the reduction | restoration casting apparatus which concerns on this invention. It is explanatory drawing which expands and shows the structure of a valve mechanism. It is a perspective view of a seal tip and a rotary valve. It is explanatory drawing which shows the state which introduce | transduced the reducing substance into the feeder part. It is explanatory drawing which shows the state which filled the molten metal in the cavity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Reduction casting apparatus 20 Mold 20a Cavity 22 Pressurization part 24 Vacuum pump 30 Hot water tank 32 Hot water supply pipe 33 Pressurized gas supply part 34 Molten metal 40 Activation chamber 41 Reductive substance supply part 43, 55 Spring 50 Valve mechanism 51 Rotary valve 51a, 51b, 51c Channel 52a, 52b, 52c Seal chip 53a, 53b, 53c Communication channel 57 Nitrogen gas supply part 58 Lever 59 Drive mechanism

Claims (5)

In a reduction casting apparatus that causes a reducing substance to act on the molten metal when filling the mold cavity with the molten metal, and fills the cavity with the molten metal while reducing the oxide film on the surface of the molten metal.
As a reducing substance supply mechanism for causing the reducing substance to act on the molten metal, a valve mechanism for controlling a supply operation of the reducing substance is provided,
The reduction casting apparatus, wherein the valve mechanism includes a rotary valve. A reduction casting apparatus that fills and molds molten metal from a hot water tank into a mold cavity,
The hot water tank is provided with an activation chamber for receiving the heat of the molten metal in the hot water tank and heating the reducing substance or the metal that generates the reducing substance,
The reduction casting apparatus according to claim 1, wherein the valve mechanism is interposed in a flow path that communicates the activation chamber and the cavity. The valve mechanism is
The rotary valve;
A seal tip disposed in sliding contact with the outer peripheral surface of the rotary valve;
The rotary valve is provided with a drive mechanism that rotates around an axis between a position where the reducing substance is supplied and a position where the supply of the reducing substance is blocked. The reduction casting apparatus according to claim 1 or 2.   The reduction casting apparatus according to claim 3, wherein the seal tip is always urged toward the outer peripheral surface of the rotary valve in a radial direction of the rotary valve.   The rotary valve acts as a spray nozzle produced by flowing a reactive gas that reacts with a carrier gas or a metal gas carrying the reducing substance into a reducing gas to generate a reducing compound, thereby reducing the reducing substance or the metal. The reduction casting apparatus according to any one of claims 1 to 4, further comprising a flow path for transferring gas.

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