JP2003048054A - Method for casting aluminum with casting metallic mold - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for casting an aluminum with a casting metallic mold with which generation of magnesium nitride is performed in a short time and the consumption of nitrogen gas can be reduced. SOLUTION: The method for casting the aluminum with the casting metallic mold, is composed of a process, in which inert gas is filled up into a cavity 25 in the metallic mold, a process, in which the magnesium layer 58a is precipitated on the surface of the cavity 25 by introducing gaseous magnesium into the cavity 25 filled with the inert gas, a process, in which the magnesium nitride 58b is generated on the surface of the cavity 25 by introducing the heated nitrogen gas into the cavity 25 and precipitating the magnesium layer 58a, and a process, in which the aluminum casting is cast while reducing the surface of molten aluminum 39 with the magnesium nitride 58b by supplying the molten aluminum into the cavity 25.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum casting method using a casting die for supplying molten aluminum to a cavity of a casting die to cast an aluminum casting in the cavity.

[0002]

2. Description of the Related Art In casting aluminum, when an aluminum melt is supplied to a cavity of a mold, an oxide film is formed on the surface of the aluminum melt, and the formed oxide film increases the surface tension of the aluminum melt, It is possible that the fluidity of the For this reason,
When an oxide film is formed on the surface of the molten aluminum, it is difficult to keep the molten aluminum around the molten metal appropriately.

[0003] Therefore, as a casting method for appropriately maintaining the molten aluminum turning property during aluminum casting, for example, Japanese Patent Application No. 11-91445 (Japanese Patent Laid-Open No. 2001-91445).
0-280063) "Aluminum casting method" has been proposed. Hereinafter, this technique will be described with reference to the drawings of the publication again.

FIG. 17 is a schematic view for explaining a conventional aluminum casting method. When casting aluminum,
First, the cavity 152 of the die 151 is filled with nitrogen gas (N ₂ gas) from the nitrogen gas cylinder 150. Next, nitrogen gas is sent to the storage tank 153, and the magnesium powder (Mg powder) in the storage tank 153 is sent into the heating furnace 155 together with the nitrogen gas. Magnesium powder is sublimated in the heating furnace 155, and the sublimated magnesium is reacted with nitrogen gas to produce a gaseous magnesium nitrogen compound (Mg
₃ N ₂ ) is obtained.

This magnesium nitrogen compound is supplied to the pipe 156.
Is introduced into the cavity 152 of the mold 151 through the above, and the introduced magnesium nitrogen compound is deposited on the surface of the cavity 152. Next, the molten aluminum 157 is supplied into the cavity 152. The supplied aluminum melt 157 is reacted with a magnesium nitrogen compound to remove oxygen from the oxide on the surface of the aluminum melt 157.

As a result, it is possible to prevent an oxide film from being formed on the surface of the aluminum melt 157 and to suppress an increase in the surface tension of the aluminum melt 157. Therefore, the cavity 15 of the molten aluminum 157
It is possible to keep the hot water sprinkling property to 2, and to improve the quality of the aluminum cast product.

Here, the above-mentioned magnesium nitrogen compound producing step and the molten aluminum pouring step will be described in detail. First, the production process of the magnesium nitrogen compound will be described. Magnesium powder is sublimated inside the heating furnace 155, and the sublimated magnesium is heated in the heating furnace 1.
Inside of 55 is reacted with nitrogen gas. Since the sublimed magnesium floats inside the heating furnace 155, the nitrogen gas adheres to the entire surface of the magnesium, and a magnesium-nitrogen compound is produced on the entire surface.

Next, the step of pouring the molten aluminum will be described. FIG. 18 is an explanatory view of a main part of a conventional aluminum casting method. After a layer 159 of a magnesium nitrogen compound (hereinafter referred to as “magnesium nitrogen compound layer 159”) is deposited on the surface of the cavity 152, the cavity 1 is formed.
A state in which molten aluminum 157 is supplied to 52 is shown.
By supplying the molten aluminum 157 to the cavity 152, the surface 157a of the molten aluminum 157
Comes into contact with the surface 159a of the magnesium nitrogen compound layer 159 to remove oxygen from the oxide 157b generated on the surface 157a of the molten aluminum 157.

[0009]

As described with reference to FIG. 18, the oxide 157b generated on the surface 157a of the aluminum melt 157 by contacting the surface 157a of the aluminum melt 157 with the surface 159a of the magnesium nitrogen compound layer 159. Can remove oxygen from. From this, in order to remove oxygen from the oxide 157b generated on the surface 157a of the molten aluminum 157,
It can be seen that only the surface 159a of the magnesium nitrogen compound layer 159 with which the surface 157a of the molten aluminum 157 is in contact should be present.

However, as described with reference to FIG. 17, since the magnesium-nitrogen compound is produced in a state where the magnesium is suspended inside the heating furnace 155, nitrogen gas adheres to the entire surface of the magnesium. Therefore, a magnesium nitrogen compound is generated on the entire surface of magnesium. Since this magnesium nitrogen compound is deposited on the surface of the cavity 152, a magnesium nitrogen compound layer 159 having a film thickness t is formed as shown in FIG.

Therefore, an excessive magnesium nitrogen compound layer 159 is deposited on the surface of the cavity 152, and it takes time to generate the magnesium nitrogen compound layer 159, which hinders the enhancement of productivity. In addition, since the magnesium-nitrogen compound layer 159 is excessively generated, the amount of nitrogen gas used increases, which hinders cost reduction.

Further, in the casting method of the above-mentioned publication, nitrogen gas is left in the cavity 152 in a state where air remains in the cavity 152 before the step of forming the magnesium nitrogen compound layer 159 on the surface of the cavity 152. The method of filling is adopted. Therefore, it is difficult to smoothly release the air from the inside of the cavity 152, and it takes time to bring the inside of the cavity 152 into an atmosphere of nitrogen gas, which hinders the enhancement of productivity.

Therefore, an object of the present invention is to provide an aluminum casting method using a casting die which can produce a magnesium nitrogen compound in a short time and can reduce the amount of nitrogen gas used. .

[0014]

To achieve the above object, the first aspect of the present invention is to provide a step of filling an inert gas into a cavity of a mold which is closed, and a cavity filled with the inert gas. Inside, a step of introducing gaseous magnesium to deposit magnesium on the cavity surface, and a step of introducing heated nitrogen gas into the cavity in which magnesium is deposited to produce magnesium nitride on the cavity surface, An aluminum casting method using a casting die is composed of a step of casting an aluminum casting in the cavity while supplying the molten aluminum into the cavity where the magnesium nitride is generated and reducing the surface of the molten aluminum with magnesium nitride. To do.

When producing magnesium nitride, first, magnesium is deposited on the surface of the cavity to form a magnesium layer, and then nitrogen gas is introduced into the cavity to produce magnesium nitride on the surface of the magnesium layer. As a result, magnesium nitride can be generated only on the surface of the magnesium layer, so that the magnesium nitride generation time can be shortened. In addition, since it is sufficient to generate magnesium nitride only on the surface of the magnesium layer, the amount of nitrogen gas used can be reduced.

Furthermore, when producing magnesium nitride, it was decided to heat the nitrogen gas and use the heated nitrogen gas. Therefore, magnesium nitride can be efficiently generated by the heated nitrogen gas.

According to the second aspect, the gas temperature in the cavity is T
(° C.), when the pressure in the cavity is P (atmospheric pressure), the relationship of T ≧ (130 × P + 270) is maintained,
The gas temperature T in the cavity and the pressure P in the cavity are set.

Since the gas temperature T (° C.) in the cavity and the pressure P (atmospheric pressure) in the cavity can be determined relatively easily based on the relationship of T ≧ (130 × P + 270), the equipment adjustment is short. It can be done in time. From the relationship of T ≧ (130 × P + 270), for example, in order to generate magnesium nitride in a state where the pressure P in the cavity is 1 atm, the gas temperature T in the cavity is set to 40.
It may be set to 0 ° C or higher.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view of a disk rotor cast by an aluminum casting method (first embodiment) using a casting die according to the present invention. Disk rotor 10
Is a member made of aluminum, which is composed of a cylindrical hub portion 11 and a disc-shaped disc portion 18 integrally formed with the hub portion 11.

The hub portion 11 has a lid 13 on the outer end of the peripheral wall 12.
Is integrally formed, and an opening 14 is formed in the center of the lid 13, and bolt holes 15 ... (... indicates a plurality. The same applies hereinafter) and stud holes 16 ... Are provided around the opening 14. It was opened. Bolts (not shown) are inserted through the bolt holes 15 ... And the disk rotor 10 is attached to the drive shaft (not shown) side with these bolts. The stud holes 16 ... Are holes into which studs (not shown) are press-fitted in order to attach wheels to the disc rotor 10.

FIG. 2 shows aluminum produced by a casting die according to the present invention.
For carrying out the method for casting a titanium (the first embodiment)
It is the whole minium casting device schematic diagram. Cast aluminum
The manufacturing apparatus 20 includes a casting apparatus body 21 including a casting die 22.
And argon in the cavity 25 provided in the casting mold 22.
Inert by introducing (Ar) gas (inert gas (rare gas))
Cavity after introducing inert gas introduction part 40 and inert gas
Introduce gaseous magnesium (Mg) into the tee 25
The magnesium introduction part 50 and the gaseous magnesium are introduced.
The heated nitrogen (N ₂) Moth
And a nitrogen gas introducing unit 60 for introducing gas.

In the casting apparatus main body 21, a fixed plate 31 is attached to a base 30, a fixed die 23 of a casting die 22 is attached to the fixed plate 31, guide rods 32 and 32 are attached to the fixed plate 31, guide rods 32, A movable plate 33 is movably supported by 32, the movable mold 24 of the casting mold 22 is attached to the movable plate 33, and a molten metal passage 34 opening to the cavity 25 is formed in the fixed mold 23 and the base 30. A plunger 35 is movably provided, a sprue 36 is formed vertically from the spout 34, and the upper end of the sprue 36 is closed with a tenon 37.
A pouring tank 38 that can communicate with 6 is provided above the sprue 36.
The stationary mold 23 and the movable mold 24 constitute the casting mold 22.

According to this aluminum casting apparatus 20,
By moving the movable plate 33 in the direction of the arrow by moving means (not shown), the movable mold 24 can be moved between the mold clamping position (the position shown in the figure) and the mold opening position. Movable type 2
The cavity 25 can be formed by the fixed die 23 and the movable die 24 by making the stationary portion 4 stand at the die clamping position. After the molten aluminum 39 is supplied to the cavity 25, the molten aluminum 39 is pressed by the plunger 35 to cast an aluminum casting in the cavity 25.

The inert gas introducing section 40 has a cavity 25.
An argon gas cylinder 42 is communicated with the above through an introduction flow path 41, and an opening / closing valve 43 for argon is provided in the middle of the introduction flow path 41. The argon opening / closing valve 43 is a valve that switches the introduction flow path 41 between an open state and a closed state. By switching the open / close valve 43 for argon to the open state, the argon in the argon gas cylinder 42 can be introduced into the cavity 25 through the introduction flow path 41.

The magnesium introducing section 50 has an introducing flow path 41.
The first magnesium introduction flow channel 51 and the second magnesium introduction flow channel 52 are provided in the middle of the above, and the sublimation part 53 is communicated with the first and second magnesium introduction flow channels 51, 52. On-off valve 57 for magnesium on the way
Equipped with.

The sublimation portion 53 communicates with the outlet end 51a of the first magnesium introducing passage 51 and the inlet end 52a of the second magnesium introducing passage 52.
4, and a heater 5 for sublimation is provided outside the housing case 54.
5 is provided. By heating the sublimation heater 55,
The inside of the housing case 54 can be heated to a predetermined temperature (for example, 400 ° C. or higher), and the magnesium ingot (magnesium) 58 inside the housing case 54 can be sublimated into a gas state.

The magnesium opening / closing valve 57 is a valve for switching the first magnesium introducing passage 51 to an open / closed state.
By switching the on-off valve 57 for magnesium to the open state,
The argon gas in the argon gas cylinder 42 is introduced into the housing case 54 via the first magnesium introduction flow path 51, and the gaseous magnesium is introduced into the second magnesium introduction flow path 52 and the introduction flow path 41. It can be introduced into the cavity 25 via.

The nitrogen gas introducing section 60 communicates with the cavity 25 through a nitrogen introducing channel 61 and a nitrogen gas cylinder 62, and a nitrogen opening / closing valve 63 and a heating section (heater) 64 are provided in the middle of the nitrogen introducing channel 61. Prepare By heating the heating unit 64, the nitrogen gas flowing through the nitrogen introduction flow channel 61 can be heated to a predetermined temperature (400 ° C. or higher, for example). The nitrogen opening / closing valve 63 is a valve that switches the nitrogen introduction flow path 61 to an open / closed state. By switching the on-off valve 63 for nitrogen to the open state, the nitrogen gas in the nitrogen gas cylinder 62 can be introduced into the cavity 25 via the nitrogen introduction flow path 61.

An example of carrying out the casting method of the first embodiment according to the present invention in the aluminum casting apparatus 20 will be described below. FIG. 3 is a flow chart for explaining the aluminum casting method of the first embodiment according to the present invention, in which ST
XX indicates a step number. ST10: Fill the cavity of the mold closed with an inert gas. ST11: Gaseous magnesium is introduced into the cavity filled with the inert gas to deposit magnesium on the surface of the cavity. ST12: A heated nitrogen gas is introduced into the cavity in which magnesium is deposited to generate magnesium nitride on the cavity surface. ST13: A molten aluminum is supplied into the cavity in which the magnesium nitride has been produced, and the aluminum casting is cast in the cavity while the surface of the molten aluminum is reduced by magnesium nitride. Hereinafter, steps ST10 to ST13 of the aluminum casting method using the casting die according to the present invention will be described with reference to FIGS.
This will be described in detail with reference to FIG.

FIG. 4 is a first explanatory view of the aluminum casting method of the first embodiment according to the present invention, showing ST10.
By switching the open / close valve 43 for argon to the open state, the argon gas (indicated by “dots”) in the argon gas cylinder 42 is introduced into the cavity 25 through the introduction flow path 41. By filling the cavity 25 with argon gas, the air in the cavity 25 is discharged to the outside of the cavity 25 from, for example, the gap between the fixed die 23 and the movable die 24. As a result, the inside of the cavity 25 can be brought into an argon gas atmosphere. After making the inside of the cavity 25 into an argon gas atmosphere, the opening / closing valve for argon 4
Switch 3 to the closed state.

FIG. 5 is a second explanatory view of the aluminum casting method of the first embodiment according to the present invention, showing ST11.
The sublimation heater 55 of the sublimation unit 53 is heated to heat the inside of the housing case 54 to a predetermined temperature (400 ° C. or higher, for example). By heating the inside of the housing case 54, the magnesium ingot 58 is sublimated into a gas state. In addition, the gaseous magnesium in the housing case 54 is indicated by “dots”.

By switching the open / close valve 57 for magnesium to the open state, the argon gas in the argon gas cylinder 42 is passed through the first magnesium introduction flow path 51 to accommodate the accommodating case 5.
Installed in 4 With the introduced argon gas, gaseous magnesium (indicated by “dots”) is introduced into the cavity 25 through the second magnesium introducing passage 52 and the introducing passage 41.

When the gaseous magnesium is introduced into the cavity 25, the second magnesium introducing passage 52 and the introducing passage 41 are heated so that the magnesium is introduced into the second magnesium introducing passage 52 and the introducing passage 41. Is preferably prevented from precipitating.

FIG. 6 is a third explanatory view of the aluminum casting method of the first embodiment according to the present invention. Gaseous magnesium introduced into the cavity 25 as indicated by the arrow touches the surface of the cavity 25 and its temperature drops to 150 to 250 ° C. The temperature of gaseous magnesium is 150 ~ 250 ℃
As a result, gaseous magnesium is deposited on the surface of the cavity 25. The deposited magnesium is used as the magnesium layer 58a. After depositing the magnesium layer 58a on the surface of the cavity 25, the magnesium on-off valve 57 (shown in FIG. 5) is switched to the closed state.

FIG. 7 is a fourth explanatory view of the aluminum casting method of the first embodiment according to the present invention, showing ST12.
The heating part 64 of the nitrogen gas introducing part 60 is brought into a heated state. In this state, the nitrogen opening / closing valve 63 is switched to the open state. By switching the on-off valve 63 for nitrogen to the open state, the nitrogen gas in the nitrogen gas cylinder 62 is made to flow into the nitrogen introduction flow path 61. As a result, the nitrogen gas in the nitrogen introducing channel 61 is heated by the heating unit 64, and the heated nitrogen gas is introduced into the cavity 25 via the nitrogen introducing channel 61.

As described above, by individually heating the nitrogen gas individually in the heating section 64, the nitrogen gas flowing through the nitrogen introduction flow path 61 can be efficiently heated to a predetermined temperature (400 ° C. or higher, for example). it can.

FIG. 8 is a fifth explanatory view of the aluminum casting method of the first embodiment according to the present invention. Here, the pressure P (atmospheric pressure) in the cavity 25 is set to the cavity 2 at this time.
When the temperature of the nitrogen gas (indicated by “dots”) in 5 is T (° C.), the gas temperature T of the nitrogen gas and the pressure in the cavity 25 are maintained so that the relationship of T ≧ (130 × P + 270) is maintained. Set P. By satisfying this condition, the magnesium layer 58a deposited on the surface of the cavity 25 reacts with the nitrogen gas to generate magnesium nitride (Mg ₃ N ₂ ) 58b on the surface of the magnesium layer 58a.

Specifically, for example, when the pressure P in the cavity 25 is 1 atm, T ≧ (130 × P + 270)
Therefore, the temperature T of the nitrogen gas in the cavity 25 is set to 4
By adjusting the temperature to 00 ° C, the magnesium layer 5
Magnesium nitride 58b can be generated on the surface of 8a. In this way, the gas temperature T of the nitrogen gas in the cavity 25 and the pressure P in the cavity 25 can be determined relatively easily based on the relationship of T ≧ (130 × P + 270), and the equipment adjustment is short. It can be done in time.

Further, when the magnesium nitride 58b is produced, the nitrogen gas is heated and the heated nitrogen gas is used. Therefore, since the nitrogen gas can be heated to a temperature at which the magnesium nitride 58b is easily generated, the magnesium nitride 58b can be efficiently generated. Then, after the magnesium nitride 58b is generated on the surface of the magnesium layer 58a, the on-off valve 63 for nitrogen is switched to the closed state.

As described with reference to FIGS. 6 and 8, when the magnesium nitride 58b is produced, magnesium is first deposited on the surface of the cavity 25 to form the magnesium layer 58a.
Then, nitrogen gas is introduced into the cavity 25 to form magnesium nitride 58b on the surface of the magnesium layer 58a. As a result, the magnesium nitride 58b can be generated only on the surface of the magnesium layer 58a, so that the generation time of the magnesium nitride 58b can be shortened. In addition, since it is only necessary to generate the magnesium nitride 58b only on the surface of the magnesium layer 58a, the amount of nitrogen gas used can be reduced.

9 (a) and 9 (b) are sixth explanatory views of the aluminum casting method of the first embodiment according to the present invention.
The first half of T13 is shown. In (a), the casting apparatus body 2
By operating the tenon 37 of 1 to open the sprue 36, the molten aluminum 39 in the pouring tank 38 is supplied to the cavity 25 through the sprue 36 and the melt passage 34 as shown by the arrow.

In (b), the surface 39a of the molten aluminum 39 supplied into the cavity 25 contacts the magnesium nitride 58b. Here, molten aluminum 3
Oxide 39b may be generated on the surface 39a of No. 9, but even if oxide 39b is generated, oxide 39b reacts with magnesium nitride 58b and oxide 3b is generated.
Oxygen can be removed from 9b.

Thus, it is possible to prevent an oxide film from being formed on the surface 39a of the molten aluminum 39 and to suppress an increase in the surface tension of the molten aluminum 39. Therefore, the cavity 25 of the molten aluminum 39
It is possible to keep the hot water circulation property suitable.

10 (a) and 10 (b) show the first embodiment of the present invention.
It is a 7th explanatory view of the aluminum casting method of an embodiment,
The latter half of ST13 is shown. In (a), after a predetermined amount of molten aluminum 39 is supplied from the pouring tank 38 to the cavity 25 side, the mortise 37 closes the sprue 36. In this state,
By pushing the plunger 35 toward the cavity 25, the molten aluminum 39 is filled in the cavity 25.

In (b), by opening the casting mold 22, the molten aluminum 39 (shown in (a)).
The aluminum casting 39c obtained by solidifying is taken out.
Since the cast aluminum product 39c can keep the hot water turning property during pouring, the quality of the cast aluminum product 39c can be further improved. This aluminum cast product 39c is processed to obtain the disc rotor 10 shown in FIG.

Next, the second embodiment will be described with reference to FIGS.
I will explain. The first embodiment in the second embodiment
The same members as those of the embodiment are designated by the same reference numerals and the description thereof will be omitted.
To do. FIG. 11 is an aluminum alloy produced by the casting die according to the present invention.
Aluminum for carrying out the aluminum casting method (second embodiment)
It is the whole um casting device schematic diagram. Aluminum casting equipment
The apparatus 80 includes a casting apparatus body 81 including a casting die 82,
In the cavity 87 provided in the casting mold 82, argon (A
r) Inert gas for introducing gas (inert gas (rare gas))
Introducing section 40 and cavity after introducing inert gas
A magnet for introducing gaseous magnesium (Mg) into 87
Introduce nesium introducing part 50 and gaseous magnesium
Nitrogen (N ₂) Gas
And a nitrogen gas introducing unit 60 for introducing.

In the casting apparatus main body 81, a fixed plate 91 is attached to the base 90, and a fixed die 83 is attached to the fixed plate 91.
A movable plate 92 is movably attached to the base 90,
2, a movable die 84 is attached to the base 90, and a moving means 93 for moving the movable plate 92 is provided on the base 90.
A core 85 is attached by a lifting means 94 so as to be able to move up and down, a molten metal channel 95 opening to a cavity 87 is formed in a movable mold 84, a molten metal port 96 is formed vertically with respect to the molten metal channel 95, and a molten aluminum 39 is stored. A bath 97 is provided above the spout 96,
The upper end of the casting mold 82 is provided with an opening 98 for venting gas and raising the riser. The fixed mold 83, the movable mold 84, and the core 85 constitute a casting mold 82.

In FIG. 11, the casting apparatus body 8
Although the sprue 96 and the opening 98 are illustrated in a large size with respect to the cavity 87 in order to facilitate understanding of No. 1, the actual sprue 96 and the opening 98 are sufficiently small with respect to the cavity 87, and the casting die 82 is Cavity 87
Can maintain an almost sealed state.

According to this aluminum casting apparatus 80,
By moving the movable plate 92 in the direction of the arrow by the moving means 93, the movable mold 84 can be moved between the mold clamping position (the position shown in the drawing) and the mold opening position. Also, the lifting means 94
By moving the core 85 in the direction of the arrow
Can be moved between the mold clamping position (position shown in the figure) and the mold opening position.

By fixing the movable die 84 and the core 85 to the stationary position, the fixed die 83, the movable die 84 and the core 85 are fixed.
The cavity 87 can be formed by. The molten aluminum 39 can be supplied to the cavity 87 to cast an aluminum casting in the cavity 87. The casting apparatus main body 81 is configured to flow the molten aluminum 39 into the cavity 87 by utilizing its own weight under atmospheric pressure, which is different from the casting apparatus main body 21 of the first embodiment in this respect.

Next, an example of carrying out the casting method of the second embodiment according to the present invention in the aluminum casting apparatus 80 will be described with reference to FIGS. 3 and 11 to 16. First, FIG.
The process of ST10 will be described. By switching the open / close valve 43 for argon shown in FIG. 11 to the open state, the argon gas in the argon gas cylinder 42 is introduced into the cavity 87 via the introduction flow path 41.

FIG. 12 is a first explanatory view of the aluminum casting method of the second embodiment according to the present invention. Cavity 87
By filling the interior with argon gas, the cavity 8
The air inside 7 is discharged to the outside of the cavity 87 from, for example, the sprue 96 and the opening 98 for degassing and feeder. As a result, the inside of the cavity 87 can be brought into an argon gas atmosphere. After the inside of the cavity 87 is set to the atmosphere of argon gas, the opening / closing valve 43 for argon (shown in FIG. 11) is switched to the closed state.

Next, the step ST11 in FIG. 3 will be described.
Returning to FIG. 11, the sublimation heater 55 of the sublimation unit 53 is brought into a heating state, and the inside of the housing case 54 is heated to a predetermined temperature (as an example,
Heat up to 400 ° C or higher). By heating the inside of the housing case 54, the magnesium ingot 58 is sublimated into a gas state. By switching the magnesium on-off valve 57 to the open state, the argon gas in the argon gas cylinder 42 is introduced into the housing case 54 via the first magnesium introduction flow path 51. Gaseous magnesium is introduced into the cavity 87 through the second magnesium introducing passage 52 and the introducing passage 41 by the introduced argon gas.

When the gaseous magnesium is introduced into the cavity 87, the second magnesium introducing channel 52 and the introducing channel 41 are heated so that the magnesium is introduced into the second magnesium introducing channel 52 and the introducing channel 41. Is preferably prevented from precipitating.

FIG. 13 is a second explanatory view of the aluminum casting method of the second embodiment according to the present invention. Cavity 87
Gaseous magnesium introduced into the inside as shown by the arrow touches the surface of the cavity 87, and the temperature drops to 150 to 250 ° C. Temperature of gaseous magnesium is 150-250
By lowering the temperature to ℃, gaseous magnesium is deposited on the surface of the cavity 87. Hereinafter, the precipitated magnesium will be described as the magnesium layer 102. Cavity 87
After the magnesium layer 102 is deposited on the surface of the, the on-off valve 57 for magnesium (shown in FIG. 11) is switched to the closed state.

Next, the step ST12 in FIG. 3 will be described. The heating section 64 of the nitrogen gas introducing section 60 shown in FIG. 11 is heated. In this state, the nitrogen opening / closing valve 63 is switched to the open state so that the nitrogen gas in the nitrogen gas cylinder 62 flows into the nitrogen introduction flow path 61. As a result, the nitrogen gas in the nitrogen introducing channel 61 is heated by the heating unit 64, and the heated nitrogen gas is introduced into the cavity 87 via the nitrogen introducing channel 61.

As described above, by individually heating the nitrogen gas in the heating section 64, the nitrogen gas flowing through the nitrogen introducing passage 61 can be efficiently heated to a predetermined temperature (400 ° C. or more, for example). it can.

FIG. 14 is a third explanatory view of the aluminum casting method of the second embodiment according to the present invention. Here, the pressure in the cavity 87 is P (atmospheric pressure), and the temperature of the nitrogen gas (indicated by “dots”) in the cavity 87 at this time is T (° C.).
Then, the temperature T of the nitrogen gas in the cavity 87 and the pressure P in the cavity 87 are set so that the relationship of T ≧ (130 × P + 270) is maintained. By satisfying this condition, the magnesium layer 102 deposited on the surface of the cavity 87 reacts with the nitrogen gas, and the magnesium layer 10
The magnesium nitride 103 can be generated on the surface of No. 2.

Specifically, for example, when the pressure P in the cavity 87 is 1 atm, T ≧ (130 × P + 270)
Therefore, the temperature T of the nitrogen gas in the cavity 87 is set to 4
By adjusting the temperature to 00 ° C, the magnesium layer 1
The magnesium nitride 103 can be generated on the surface of 02. In this way, the third pressure P and the gas temperature T of the nitrogen gas in the cavity 87 can be relatively easily determined based on the relationship of T ≧ (130 × P + 270), so that the equipment can be set for a short time. Can be done at.

Further, when the magnesium nitride 103 is produced, the nitrogen gas is heated and the heated nitrogen gas is used. Therefore, the nitrogen gas can be heated to a temperature at which the magnesium nitride 103 can be easily generated, so that the magnesium nitride 103 can be efficiently generated. Then, after the magnesium nitride 103 is generated on the surface of the magnesium layer 102, the nitrogen opening / closing valve 63
(Shown in FIG. 11) is switched to the closed state.

As shown in FIGS. 13 and 14, when the magnesium nitride 103 is produced, first, magnesium is deposited on the surface of the cavity 87 to form the magnesium layer 102.
Then, nitrogen gas is introduced into the cavity 87 to form magnesium nitride 103 on the surface of the magnesium layer 102. As a result, the magnesium nitride 103 can be generated only on the surface of the magnesium layer 102, so that the generation time of the magnesium nitride 103 can be shortened. In addition, since it is sufficient to generate the magnesium nitride 103 only on the surface of the magnesium layer 102, the amount of nitrogen gas used can be reduced.

Next, the step ST13 of FIG. 3 will be described.
15A and 15B are fourth explanatory views of the aluminum casting method of the second embodiment according to the present invention. In (a), by tilting the pouring tank 97 of the casting apparatus main body 81, the molten aluminum 39 in the pouring tank 97 is supplied to the cavity 87 through the sprue 96 and the melt passage 95 as shown by the arrow. Here, since the third pressure P in the cavity 87 is adjusted to be equal to or lower than the atmospheric pressure, it is possible to smoothly fill the cavity 87 with the molten aluminum 39.

In (b), the surface 39 a of the molten aluminum 39 supplied into the cavity 87 contacts the magnesium nitride 103. Here, molten aluminum 3
Oxide 39b may be generated on the surface 39a of No. 9, but even if oxide 39b is generated, oxide 39b reacts with magnesium nitride 103 and oxide 3
Oxygen can be removed from 9b.

Thus, it is possible to prevent an oxide film from being formed on the surface 39a of the molten aluminum 39 and to suppress an increase in the surface tension of the molten aluminum 39. Therefore, the cavity 87 of the molten aluminum 39
It is possible to keep the hot water circulation property suitable.

FIGS. 16 (a) and 16 (b) show the second embodiment of the present invention.
It is 5th explanatory drawing of the aluminum casting method of embodiment.
In (a), from the pouring tank 97 to the molten aluminum 39
After supplying a predetermined amount to the cavity 87, the pouring tank 97 is returned horizontally. After the molten aluminum 39 is solidified, the raising and lowering means 94 lowers the core 85 as shown by the arrow, and the moving means 93 moves the movable die 84 as shown by the arrow to open the casting die 82.

In (b), the casting mold 82 is opened to melt the molten aluminum 39 (shown in (a)).
The aluminum cast product 105 obtained by solidifying is taken out.
Since the cast aluminum product 105 can keep the hot running property during pouring, the quality of the cast aluminum product 105 can be further improved. After removing the non-product part 105a and the non-product part 105b from the aluminum cast product 105, the product part is processed to obtain a cylinder block of the engine.

In the above embodiment, an example was described in which the atmosphere of the argon gas in the cavity of the casting mold was changed, but it is also possible to use an inert gas such as helium instead of the argon gas. is there. Furthermore, it is also possible to use nitrogen gas which is chemically inert as compared with air, instead of the inert gas such as argon gas.

The aluminum casting method of the above embodiment can be applied to, for example, an aluminum alloy containing silicon, nickel or copper, or pure aluminum.

[0069]

The present invention has the following effects due to the above configuration. According to claim 1, when producing magnesium nitride,
First, magnesium is deposited on the surface of the cavity to form a magnesium layer, and then nitrogen gas is introduced into the cavity to generate magnesium nitride on the surface of the magnesium layer. As a result, magnesium nitride can be produced on the surface of the magnesium layer, so that the production time of magnesium nitride can be shortened. Therefore, the productivity of the aluminum cast product can be improved.

In addition, since it is sufficient to generate magnesium nitride only on the surface of the magnesium layer, the amount of nitrogen gas used can be reduced. Therefore, the cost of the cast aluminum product can be suppressed.

Further, when producing magnesium nitride, nitrogen gas was heated and the heated nitrogen gas was used. Therefore, magnesium nitride can be efficiently generated by the heated nitrogen gas. Therefore, the productivity of the aluminum cast product can be improved.

In claim 2, T ≧ (130 × P + 270)
Since the gas temperature T (° C.) in the cavity and the pressure P (atmospheric pressure) in the cavity can be determined comparatively easily based on the relationship, the equipment can be adjusted in a short time.

[Brief description of drawings]

FIG. 1 is a perspective view of a disk rotor cast by an aluminum casting method (first embodiment) using a casting die according to the present invention.

FIG. 2 is an overall schematic view of an aluminum casting apparatus for carrying out an aluminum casting method (first embodiment) using a casting die according to the present invention.

FIG. 3 is a flowchart illustrating an aluminum casting method according to the first embodiment of the present invention.

FIG. 4 is a first explanatory view of the aluminum casting method of the first embodiment according to the present invention.

FIG. 5 is a second explanatory view of the aluminum casting method of the first embodiment according to the present invention.

FIG. 6 is a third explanatory view of the aluminum casting method according to the first embodiment of the present invention.

FIG. 7 is a fourth explanatory view of the aluminum casting method of the first embodiment according to the present invention.

FIG. 8 is a fifth explanatory view of the aluminum casting method according to the first embodiment of the present invention.

FIG. 9 is a sixth explanatory view of the aluminum casting method according to the first embodiment of the present invention.

FIG. 10 is a seventh explanatory view of the aluminum casting method according to the first embodiment of the present invention.

FIG. 11 is an overall schematic view of an aluminum casting apparatus for carrying out an aluminum casting method (second embodiment) using a casting die according to the present invention.

FIG. 12 is a first explanatory view of the aluminum casting method of the second embodiment according to the present invention.

FIG. 13 is a second explanatory view of the aluminum casting method of the second embodiment according to the present invention.

FIG. 14 is a third explanatory view of the aluminum casting method of the second embodiment according to the present invention.

FIG. 15 is a fourth explanatory view of the aluminum casting method of the second embodiment according to the present invention.

FIG. 16 is a fifth explanatory view of the aluminum casting method of the second embodiment according to the present invention.

FIG. 17 is a schematic view illustrating a conventional aluminum casting method.

FIG. 18 is an explanatory view of a main part of a conventional aluminum casting method.

[Explanation of symbols]

20, 80 ... Aluminum casting device, 22, 82 ... Casting die (mold), 25, 87 ... Cavity, 39 ... Aluminum melt, 39a ... Aluminum melt surface, 39
c, 105 ... Aluminum casting, 58a, 102 ... Magnesium layer, 58b, 106 ... Magnesium nitride, P
... pressure in the cavity, T ... gas temperature in the cavity.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Sugaya Advantage             1-10, Shin-Sayama, Sayama City, Saitama Prefecture             Within Da Engineering Co., Ltd. (72) Inventor Takashi Kato             1-10, Shin-Sayama, Sayama City, Saitama Prefecture             Within Da Engineering Co., Ltd. (72) Inventor Ryuji Echigo             1-10, Shin-Sayama, Sayama City, Saitama Prefecture             Within Da Engineering Co., Ltd. (72) Inventor Satoshi Matsuura             1-10, Shin-Sayama, Sayama City, Saitama Prefecture             Within Da Engineering Co., Ltd.

Claims (2)

[Claims] 1. A step of filling an inert gas into a cavity of a closed mold, and a step of introducing gaseous magnesium into the cavity filled with the inert gas to deposit magnesium on the surface of the cavity. And a step of introducing heated nitrogen gas into the cavity in which the magnesium has been deposited to generate magnesium nitride on the cavity surface, and supplying molten aluminum into the cavity in which the magnesium nitride has been generated to supply molten aluminum. And a step of casting an aluminum casting in the cavity while reducing the surface of magnesium with magnesium nitride, and an aluminum casting method using a casting die. 2. The temperature of the gas in the cavity is T
(° C.), when the pressure in the cavity is P (atmospheric pressure), the relationship of T ≧ (130 × P + 270) is maintained,
The method of casting aluminum by a casting die according to claim 1, wherein a gas temperature T in the cavity and a pressure P in the cavity are set.