JPH07314113A - Manufacturing method for cast products with low oxide content - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a method for manufacturing a cast product such as an aluminum alloy or a magnesium alloy in which a small amount of oxide is mixed into the product during high pressure casting. A vertically movable injection sleeve is provided with a vertically movable molten metal buffer plate, an appropriate annular gap is provided between the injection sleeves, and the molten metal buffer plate is held at an appropriate height of the injection sleeve. Once the molten metal is poured toward the molten metal buffer plate from the ladle, the molten metal buffer plate is raised as the molten surface rises, and the residual air remaining on the lower surface side of the molten metal buffer plate when the pouring is completed is removed. The air is discharged from the residual air discharge pipe provided near the edge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a cast product containing a small amount of oxide so as to obtain a cast product having a small amount of oxide and excellent mechanical properties.

[0002]

2. Description of the Related Art FIG. 16 is a front view of a conventional biscuit. An injection molding device such as a die casting machine is equipped with a fixed mold mounted on a fixed plate and a movable mold mounted on a movable plate, and a cavity is formed at a joint portion between these molds that are clamped. Has been formed. In addition, a fixed sleeve, which communicates with the cavity through a gate, is fitted in the sleeve hole of the fixed mold, and the injection sleeve of the injection cylinder supported by the fixed plate is attached to and detached from this fixed sleeve. Freely joined. With this structure, when the molten metal is supplied to the injection sleeve and joined to the fixed sleeve, the plunger tip provided in the injection cylinder is hydraulically advanced, and the molten metal in the injection cylinder is pushed, the molten metal is It is injected into the cavity through the fixed sleeve and the gate.

Since the molten metal in the cavity is solidified into a product, the mold is opened and the product is taken out.
The surplus casting material is separated from the product and left in the injection sleeve and the gate. That is, when the molten metal solidifies, a large-diameter, thin-cylindrical molten solidified material, commonly called a biscuit, remains in the mold cavity, and a small diameter that also protrudes from the center of the molten molten metal solidified in the gate. A columnar molten metal solidified substance remains (hereinafter, the entire cast surplus material composed of the molten metal solidified substance in the sleeve and the molten metal solidified substance in the gate is referred to as a biscuit. Further, the molten metal solidified substance in the sleeve is the large diameter member 72. The solidified material in the gate is referred to as a small diameter member 73). When casting, if non-metallic inclusions such as molten oxide enter the cavity,
Since the quality of the product deteriorates, generally, the gate shown in FIG.
There is a case where the wire netting denoted by reference numeral 74 is loaded for each shot. Then, this wire net is left embedded in the small diameter member. The biscuit 71 is separated from the cast product thus formed.

[0004]

However, when the metal net is loaded into the gate from below as in the prior art, and the aluminum alloy poured into the injection sleeve is pushed up by the plunger tip to fill the mold cavity, The oxides and non-metal inclusions on the surface of the molten metal prevent a part of mixing into the product by the metal net 74, but the remaining oxides and non-metallic inclusions are finely crushed by the metal net 74 and filled in the cavity together with the molten metal. It Therefore, good mechanical properties were obtained. However, the conventional biscuit 71 is integrally formed with the large-diameter member 72 and the small-diameter member 73 as described above, and the wire net 7 is attached to the small-diameter member 73 that is solidified in the gate.
Since 4 was left buried, there was a problem that the yield of the material was poor because it could not be recovered and reused as it was.

In view of the above conventional problems, the present invention has an object to provide a method for producing a cast product such as an aluminum alloy or a magnesium alloy in which a small amount of oxide is mixed into the product during high pressure casting. is there.

[0006]

In order to solve such a problem, according to the present invention, a moving shaft for vertically moving a molten metal buffer plate having an annular gap between vertical injection sleeves coaxially with the injection sleeves. Using an oxide removing device fixed to the tip of the injection sleeve, while pouring it toward the molten metal buffer plate from above the injection sleeve in a state of being positioned at an appropriate height inside the injection sleeve, it is made to flow down from the annular gap. The molten metal buffer plate is raised in accordance with the molten metal surface rising speed, and when the pouring is completed, the molten metal buffer plate is positioned above the molten metal buffer plate to remove the oxide remaining on the molten metal buffer plate. A method for manufacturing a cast product with a small amount of oxide mixed so as to be taken out integrally with a molten metal buffer plate, using a molten metal buffer plate in which a part of the edge is raised or a pipe is arranged, Buffering the molten metal during hot water supply The air remaining in the lower surface side of the to discharge on the molten metal.

[0007]

Function: An appropriate annular gap is provided between the molten metal buffer plates inserted into the injection sleeve, and the molten metal buffer plates are positioned at a predetermined height. Next, when a desired amount of molten aluminum alloy is poured into the injection sleeve from the ladle, the molten metal once drops onto the molten metal buffer plate with a small drop and then flows down the inner wall surface of the injection sleeve through the annular gap. The residual air that has lost its escape to the lower surface of the molten metal buffer plate when it is stored in the injection sleeve is smoothly discharged to the top of the molten metal through a discharge pipe. Is prevented from scattering with turbulent flow, and the molten metal is less likely to be newly oxidized in the injection sleeve.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A concrete embodiment of a method for producing a cast product with a small amount of oxides according to the present invention will be described below in detail with reference to the drawings.

FIGS. 1 to 6 are structural views in which residual air discharge means are provided on a molten metal buffer plate, and FIGS. 7 to 12 show a method for removing oxides mixed into an injection sleeve when pouring molten metal according to an embodiment of the present invention. FIG. 13 is an explanatory view showing a state in which residual air is present on the lower surface side of the molten metal buffer plate, FIG. 14 is a front view of a vertical casting die casting machine, and FIG. 15 is a vertical sectional view of a vertical injection device. is there.

In FIGS. 14 and 15, a pit 1 having a rectangular shape in plan view is provided below the floor surface. At both ends of the pit 1, a pair of machine bases framed by steel plates or shaped steels are provided. 2 is extended upright on the floor surface, and a stationary platen 3 formed in a substantially square shape is placed on one end of these machine bases 2 and its legs 3a are bolted. It is fixed.

An end platen 4 is erected and fixed to the other end of the machine base 2 so as to be movable and adjustable. The fixed platen 3 and the end platen 4 are four corners with four tie rods 5. After being connected and adjusted for movement, they are fixed with a nut 6. Numeral 7 is a movable platen which is fitted into the tie rods 5 at the four corner holes so as to be able to move forward and backward with respect to the fixed platen 3. The movable platen 7 is provided between the piston rod 9 of the mold clamping cylinder 8 and the toggle mechanism 10. The piston plate 9 is moved forward and backward by hydraulic pressure to move forward and backward with respect to the fixed platen 3.

A fixed mold 11 having cavities 11a, 12a and a biscuit portion 15 and a movable mold 12 are mounted on the fixed platen 3 and the movable platen 7, respectively, and driven by a mold clamping cylinder 8 to move the movable platen. The mold is clamped as shown in FIG. 1 by advancing the mold 7 from the mold open state.

Next, a vertical casting type injection device 13 arranged in the pit 1 will be described. Reference numeral 20 denotes an injection cylinder pivotally supported by a seat 18 fixedly provided on the bottom surface of the pit 1 via a pin 19, and the injection cylinder 20, the docking frame 22, and the injection sleeve 24 are sequentially arranged from the lower side. It has a staircase configuration. A piston 26 is installed in the injection cylinder 20.
A rod 28 extending upward is connected to the.
The docking frame 22 is provided with a cylinder hole 30 extending in the vertical direction, a docking ram 32 is inserted into the cylinder hole 30, and the lower end of the docking ram 32 is a flange 34 formed on the upper surface of the injection cylinder 20.
Is stuck to.

The injection sleeve 24 is connected to the upper side of the docking frame 22 via a connecting member 36, and the upper end thereof can be inserted into the lower end of the biscuit portion 15. A plunger tip 38 is slidably installed in the injection sleeve 24, and a lower end of a plunger 40 holding the plunger tip 38 is a coupling 42.
It is connected to the upper end of the rod 28 via. A tilting cylinder 44 is pivotally supported by a side wall of the pit 1 via a seat 46 and a pin 48, and a rod 52 connected to a piston 50 of the tilting cylinder 44.
Has its tip pivotally attached to the side surface of the flange 34 of the injection cylinder 20 via a joint 54 and a pin 56.

Reference numeral 60 is an oxide removing device, which comprises a molten metal buffer plate 62 and a moving shaft 64. The molten metal buffer plate 62 serves as rectification without generating a turbulent flow such as twist in the molten metal 68 poured from the ladle 66, and the injection sleeve 2
The inner wall surface of 4 is made to flow down. The distal end of the moving shaft 64 is fixed in the direction orthogonal to the center of the molten metal buffer plate 62, and the other end of the moving shaft 64 moves up and down in the axial direction of the injection sleeve 24 while being held by, for example, a robot (not shown). It is possible. The projected area A1 of the molten metal buffer plate 62 is 60 to the sectional area A2 of the injection sleeve 24.
A flat plate having a diameter of 95%, preferably 75 to 90% is used.

When the projected area A1 of the molten metal buffer plate 62 is 60% or less of the cross-sectional area A2 of the injection sleeve 24, the molten metal 68 poured into the injection sleeve 24 once hits the molten metal buffer plate 62 and the Since the molten metal 68 falls without adhering to the wall surface, the molten metal 68 scatters with turbulence and oxidizes the molten metal 68. Further, when the projected area A1 of the molten metal buffer plate 62 is 95% or more of the sectional area A2 of the injection sleeve 24, it is difficult to replace the molten metal 68 flowing down through the annular gap 69 with the air retained in the injection sleeve 24. ,
The pouring speed from the ladle 66 to the injection sleeve 24 becomes very slow.

Further, as shown in FIG. 1, the molten metal buffer plate 62 is for temporarily receiving the molten metal 68 poured from the ladle 66, and its set position H2 is the height H of the injection sleeve 24.
If it is less than 1/5 of 1, the large amount of molten metal 68 drops from the pouring position of the ladle 66 to the molten metal buffer plate 62, and many bubbles are generated in the poured molten metal 68. Will increase. Further, the height H2 of the molten metal buffer plate 62
Is greater than 4/5 of the height H1 of the injection sleeve 24,
Molten metal 6 from the pouring position of the ladle 66 to the molten metal buffer plate 62
Although there are few bubbles in the molten metal 68 that has been poured because the head is small, the height between the molten metal buffer plate 62 and the upper end surface of the injection sleeve 24 is small and it is difficult to pour the molten metal 68 so as not to overflow. . For this reason, the height H2 of the molten metal buffer plate 62 is set to 1/5 to 4/5 of the height H1 of the injection sleeve 24, preferably 2/5, before pouring the molten metal 68 into the injection sleeve 24.
It is better to be located at ~ 3/5.

Further, in the present embodiment, the residual air discharge pipe 85 or a standing portion 87 in which a part of the trailing edge portion is raised to, for example, 30 to 60 degrees is disposed in the vicinity of the edge portion of the molten metal buffer plate 62. Has become.

The air in the injection sleeve 24, which has been delayed by the molten metal 68 that has flowed into the injection sleeve 24 over the entire annular gap 69 during pouring, is trapped in the lower surface 62a of the molten metal buffer plate 62 as shown in FIG. The contained residual air is discharged into the residual air discharge pipe 85 and the rising portion 8.
It is configured to be discharged onto the molten metal via 7.

The residual air discharge pipe 85 or the standing portion 87
It is preferable that the molten metal buffer plate 62 is disposed closer to the edge portion than to the central portion of the molten metal buffer plate 62. The reason is that the injection device 13 is tilted for pouring, and the axis of the moving shaft 64 of the oxide removing device 60 is aligned (coaxially) with the axis of the injection sleeve 24. When pouring into the injection sleeve 24 under
Residual air that has been lost and has been trapped inside moves toward the left end of the molten metal buffer plate 62 as shown in FIG. 13 and is discharged onto the molten metal through the residual air discharge pipe 85 or the rising portion 87 described above. Is configured to. The length of the residual air discharge pipe 85 is preferably such that the molten metal 68 does not enter during pouring.

As the material of the oxide removing device 60, for example, a metal, a nonmetal, or a composite material thereof that does not melt against the molten aluminum alloy or magnesium alloy is used. Reference numeral 58 is a fixed sleeve, 65 is a mold sleeve, and 6
Reference numeral 6 is a ladle, 67 is a gate portion, and 69 is an annular gap provided between the molten metal buffer plate 62 and the injection sleeve 24.

The operation of the vertical injection device constructed as above will be described. In this embodiment, a case where a circular residual air discharge pipe 85 is used for the molten metal buffer plate 62 will be described. First, the movable platen 7 is advanced by the mold clamping cylinder 8 to clamp the molds 11 and 12, and then the rod 52 of the tilting cylinder 44 is advanced to tilt to the chain line position as shown in FIG. A lubricant is spray-supplied to 24 from a lubricant spray device (not shown). Next, the molten metal buffer plate 62 is lowered in the axial direction of the injection sleeve 24 while the moving shaft 64 of the oxide removing device 60 is held by a gripping device such as a robot (not shown) so as to be positioned coaxially with the injection sleeve 24, The molten metal buffer plate 62 and the injection sleeve 24 are positioned so as to have a uniform annular gap 69.
As shown in, the height H2 of the molten metal buffer plate 62 in the injection sleeve 24 is set to be about 2 / height of the height H1 of the injection sleeve 24, for example.
Position it to be 5. Next, when, for example, an aluminum alloy molten metal 68 is pumped up from a molten metal holding furnace (not shown) by a ladle 66, and while gently tilting on the injection sleeve 24, once gently pouring the molten metal 68 onto the molten metal buffer plate 62 having a small head. The molten metal 68 flows straight from the annular gap 69 on the inner wall surface of the injection sleeve 24, flows down, is replaced with air, and is gradually stored in the injection sleeve 24 (FIG. 7). The molten metal 68 is injected from the annular gap 69 into the injection sleeve 24.
When flowing down into the molten metal, the swirling flow of the molten metal 68 is made as slow as possible to prevent the entrainment of air and also to reduce the entrainment of the oxide 70 in the molten metal 68.

Subsequently, the molten metal buffer plate 6 is inserted into the injection sleeve 24.
When the molten metal 68 is poured through 2, the level of the molten metal 68 gradually increases and the residual air in the injection sleeve 24 is also replaced with the molten metal 68 and discharged from the annular gap 69 (FIG. 8).

However, when pouring the molten metal from the ladle 66 toward the molten metal buffer plate 62 in the injection sleeve 24, if the pouring amount is increased in order to shorten the pouring time and reduce the generation of the oxide 70, the pouring amount is increased. The molten metal 68 is the molten metal buffer plate 6
On the other hand, the residual air in the injection sleeve 24 loses its escape and is driven to the lower surface 62a side of the molten metal buffer plate 62 in an attempt to flow down from the annular gap 69 as a whole.

By such a phenomenon, the residual air driven into the lower surface 62a side of the molten metal buffer plate 62 is smoothly discharged onto the molten metal surface 80 from the above-mentioned residual air discharge pipe 85.

If such a residual air discharge pipe 85 is not used, the residual air is heated and compressed by the molten metal 68 by the subsequent pouring of the injection sleeve 24, and the pouring amount is changed to reduce the gap 69. The residual air contained when the portion is opened is discharged into the atmosphere while making countercurrent contact with the molten metal 68 flowing down from the gap 69.

Since the residual air becomes a bubble state, that is, a state having a large specific surface area, when it comes into countercurrent contact with the molten metal 68 flowing down, the generation of the secondary oxide 70 is promoted also in the injection sleeve 24. Prone. In this embodiment, in order to prevent such a phenomenon, at least one residual air discharge pipe 85 is provided at the edge of the molten metal buffer plate 62 (a plurality of residual air discharge pipes 85 are provided in the radial direction from the edge of the molten metal buffer plate 62 toward the center). May be)
The residual air trapped on the lower surface 62a of the molten metal buffer plate 62 is easily discharged (FIG. 9).

Molten metal 68 stored in the injection sleeve 24
As the molten metal surface gradually approaches the molten metal buffer plate 62, the molten metal buffer plate 6
The molten metal buffer plate 62 is lifted while being careful that 2 is constantly positioned above the surface of the molten metal 68. Immediately before the completion of pouring the molten metal into the injection sleeve 24, the rise of the molten metal buffer plate 62 is stopped, and the molten metal 68 is positioned slightly above the upper surface of the molten metal buffer plate 62.

When the pouring is completed, the molten metal surface 80 and the molten metal buffer plate 62 intersect at an appropriate angle (this angle is the same as the tilt angle of the injection device 13) as shown in FIG. In this case, the left half of the molten metal buffer plate 62 is made of oxide 70.
Is exposed on the molten metal surface 80 while capturing
8 and the oxide 70 remains floating on the molten metal surface 80 and is not trapped.

After that, the oxide 7 is formed on the upper surface of the molten metal buffer plate 62.
In the state where 0 is captured, it is pulled up from the injection sleeve 24 and retracted to an appropriate position as it is (FIG. 11).

The oxide 70 thus trapped on the molten metal buffer plate 62 is taken out integrally with the molten metal buffer plate 62, and is moved to an appropriate position to become the oxide 70 trapped on the molten metal buffer plate 62. For example, compressed air 81 or the like is blown to remove the oxide 70 that is attached and trapped on the molten metal buffer plate 62.

When removing the oxide 70, compressed air 81 is used.
However, the oxide 70 may be removed by external heating, vibration, suction or gripping (FIG. 12).

On the other hand, when pouring into the injection sleeve 24 is completed, pressure oil is introduced to the piston rod 52 side of the tilting cylinder 44 to erect the injection device 13. Next, when pressure oil is introduced into the cylinder hole 30, the docking frame 22 starts to rise at a predetermined speed to bring the injection sleeve 24 into contact with the fixed sleeve 58. Further, pressure oil is introduced to the head side of the piston 26 to raise the plunger tip 38 and raise the molten metal 68 into the mold sleeve 65. Finally, pressure oil is introduced into the injection cylinder 20 to further raise the plunger tip 38 and to fill the molten metal 68 into the cavities 11a and 12a.
To be filled. Molten metal 68 into the cavities 11a, 12a
After the solidification is completed, the injection plunger 20 and the docking frame 22 are lowered, tilted to the chain line position shown in FIG. 15, and the molds 11 and 12 are opened to open the cavity 1
The cast products in 1a and 12a are taken out, but when the mold is opened, the product and the biscuit 71 are cut and separated to complete one cycle.

In the embodiment, the case where the circular residual air discharge pipe 85 is used for the molten metal buffer plate 62 has been described.
Similar effects can be obtained even with the structure shown in FIGS.

[0035]

As is apparent from the above description, according to the present invention, the molten metal buffer plate having the annular gap between the vertical injection sleeves is vertically moved in the axial direction of the injection sleeves. Using an oxide removal device fixed to
While pouring at a suitable height in the injection sleeve from above the injection sleeve toward the molten metal buffer plate, the molten metal is allowed to flow down from the annular gap, and the molten metal buffer is adjusted in accordance with the rising speed of the molten metal. An oxide that raises the plate and positions the molten metal surface above the molten metal buffer plate when pouring is completed so that the oxide remaining on the molten metal buffer plate is taken out integrally with the molten metal buffer plate. A method of manufacturing a cast product with a small amount of mixing, in which a part of the edge portion is erected or a molten metal buffer plate provided with a pipe is used, and air remaining on the lower surface side of the molten metal buffer plate during hot water supply is used. Since the air is discharged onto the molten metal, it is possible to prevent the inclusion of outside air and oxides in the molten metal and the generation of secondary oxides due to the residual air in the injection sleeve during pouring. Finer than cast products Excellent cast product of quality can be obtained. Further, since the wire mesh is not buried in the biscuit portion, the surplus casting material (biscuit) can be effectively used, and the yield is improved.

[Brief description of drawings]

FIG. 1 is a partially cut sectional view showing an embodiment of the present invention in which a circular residual air discharge pipe is provided on a molten metal buffer plate.

FIG. 2 is a plan view as seen from AA of FIG.

FIG. 3 is a partially cut cross-sectional view showing another embodiment of the present invention in which a rising portion for discharging residual air is provided at an edge portion of a molten metal buffer plate.

FIG. 4 is a plan view seen from BB of FIG.

FIG. 5 is a partially cut cross-sectional view showing still another embodiment of the present invention, in which a molten buffer plate is provided with a half-divided residual air discharge pipe.

FIG. 6 is a plan view seen from CC of FIG.

FIG. 7 is an explanatory view showing a state of pouring molten metal into the injection sleeve according to the embodiment of the present invention.

FIG. 8 is an explanatory diagram showing a state of pouring molten metal into the injection sleeve according to the embodiment of the present invention.

FIG. 9 is an explanatory diagram showing a state of pouring molten metal into the injection sleeve according to the embodiment of the present invention.

FIG. 10 is a diagram illustrating a method of removing oxides using a molten metal buffer plate according to an embodiment of the present invention.

FIG. 11 is a diagram illustrating a method of removing oxides by using a molten metal buffer plate according to an embodiment of the present invention.

FIG. 12 is an explanatory diagram for removing oxides trapped on the molten metal buffer plate.

FIG. 13 is an explanatory diagram showing a state where residual air is present on the lower surface side of the molten metal buffer plate.

FIG. 14 is a front view of a vertical casting die casting machine.

FIG. 15 is a vertical sectional view of a vertical injection device.

FIG. 16 is a front view of a conventional biscuit.

[Explanation of symbols]

 3 Fixed Platen 4 End Platen 5 Tie Rod 10 Toggle Mechanism 11 Fixed Die 12 Movable Dies 11a, 12a Cavity 13 Injection Device 15 Biscuit Part 20 Injection Cylinder 22 Docking Frame 24 Injection Sleeve 32 Docking Ram 38 Plunger Chip 44 Tilting Cylinder 58 Fixed Sleeve 60 Oxide removal device 62 Molten metal buffer plate 64 Moving shaft 65 Mold sleeve 68 Molten metal 69 Annular gap 70 Oxide 71 Biscuit 74 Wire netting 80 Hot water surface 81 Compressed air 85 Residual air discharge pipe 87 Standing part

Claims (1)

[Claims] 1. An oxide removing device, in which a molten metal buffer plate having an annular gap between vertical injection sleeves is fixed to the tip of a moving shaft that moves up and down coaxially with the injection sleeve, is used. While pouring toward the molten metal buffer plate from above the injection sleeve in a state of being positioned at an appropriate height, the molten metal buffer plate is caused to flow down from the annular gap, and the molten metal buffer plate is raised in accordance with the molten metal surface rising speed, When the pouring is completed, the molten metal surface is positioned above the molten metal buffer plate, and the oxide remaining on the molten metal buffer plate is taken out integrally with the molten metal buffer plate. A method of manufacturing a product, in which a portion of an edge portion is erected or a molten metal buffer plate provided with a pipe is used to discharge air remaining on the lower surface side of the molten metal buffer plate onto the molten metal during hot water supply. Special feature A method for producing a cast product with a small amount of oxides as a characteristic.