JPH0716721A - Production of cast product with a small amount of oxide mixed - Google Patents

Abstract

PURPOSE:To produce a cast product having excellent quality by positioning the molten metal surface before completing the pouring above a cushon plate and taking out the remaining oxide on the cushon plate integrally with the cushon plate. CONSTITUTION:An injection device 13 is arranged in a pit 1. The molten metal cushon plate 62 in the device 13 having an annular gap with a vertical injection sleeve 24 is fixed to the tip part of a shifting shaft 64 vertically shifting in the coaxial direction with the injection sleeve 24. After pouring the molten metal toward the molten metal cushon plate 62 from the upper part in the state of positioning the molten metal cushon plate 62 at a suitable height in the injection sleeve 24, the molten metal is allowed to flow down from the annular gap. simultaneously the molten metal cushon plate 62 is risen matched with the molten metal 68 surface rising speed. By positioning the molten metal surface at the upper part than the cushon plate 62 before completing the pouring, the oxide remaining on the cushon plate 62 is taken out integrally with the cushon plate 62. By this method, the entrapment of the air and the oxide into the molten metal can be prevented.

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 an oxide so as to obtain a cast product containing a small amount of an oxide and excellent in mechanical properties.

[0002]

2. Description of the Related Art FIG. 8 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 on the fixed plate side is attached to and detached from this fixed sleeve. Freely joined. With this configuration, when the molten metal is supplied to the injection sleeve and joined to the fixed sleeve, and the plunger tip provided in the injection cylinder is moved forward by hydraulic pressure or the like to push the molten metal in the injection cylinder, 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 referred to as a 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, a wire mesh indicated by reference numeral 74 in FIG. 8 may be loaded in the gate 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 1 is integrally formed with the large diameter member 2 and the small diameter member 3 as described above, and the wire net 4 remains embedded in the small diameter member 3 which is the solidified material in the gate. However, there is a problem that the yield of the material is poor because it cannot be recovered and reused as it is.

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

[0006]

In order to solve such a problem, in the method for manufacturing a cast product containing a small amount of oxide according to the present invention, 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, and is poured from above the injection sleeve toward the molten metal buffer plate while being positioned at an appropriate height inside the injection sleeve. While flowing down from the annular gap, the molten metal buffer plate is raised in accordance with the molten metal surface rising speed, and the molten surface is positioned above the buffer plate before the completion of pouring, and is placed on the buffer plate. The residual oxide was taken out integrally with the buffer plate.

[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. Then, when a desired amount of molten aluminum alloy is poured from the ladle to the injection sleeve, 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 by rectifying through the annular gap. It is then stored in the injection sleeve. Therefore, the molten metal poured into the injection sleeve is prevented from scattering with turbulence, and the molten metal is less likely to be newly oxidized in the injection sleeve. By placing the upper surface of the molten metal above the upper surface of the molten metal buffer plate before pouring is completed, the generated oxide is attached to the upper surface of the molten metal buffer plate and is taken out together with the molten metal buffer plate.

[0008]

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

FIG. 1 is a front view of a vertical casting die casting machine, FIG. 2 is a vertical sectional view of a vertical injection device, and FIGS. 3 to 6 show a state of pouring molten metal into an injection sleeve according to an embodiment of the present invention. Explanatory drawing, FIG. 7 shows another embodiment similar to the embodiment of the present invention.

In the figure, a pit 1 having a rectangular shape in plan view is provided below the floor, and both ends of this pit 1 are
A pair of machine bases 2 each having a frame shape made of a steel plate, a shaped steel or the like extend on the floor surface and stand upright. One end of each of the machine bases 2 has a fixed platen formed in a substantially square shape. 3 is placed and its leg portions 3a are fixed by bolting.

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 a rectifying mechanism for the molten metal 68 poured from the ladle 66 without generating a turbulent flow such as a twist, and thus the injection sleeve 24
It is designed to flow down the inner wall surface of. The tip of the moving shaft 64 is fixed in a direction orthogonal to the center of the molten metal buffer plate 62, and the other end of the moving shaft 64 is held in the axial direction of the injection sleeve 24 while holding the oxide removing device 60 (not shown). It is configured to be movable up and down. The projected area A1 of the molten metal buffer plate 62 is 60 to 95 of the sectional area A2 of the injection sleeve 24.
%, And preferably a flat plate having a diameter of 75 to 90% is used.

When the projected area A1 of the molten metal buffer plate 62 is 60% or less of the sectional area A2 of the injection sleeve 24, the injection sleeve 24 is
Since the molten metal 68 poured into the molten metal 68 once hits the molten metal buffer plate 62 and falls without adhering to the inner wall surface of the injection sleeve 24, the molten metal 68 scatters with turbulence and oxidizes the molten metal 68. become. 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 staying in the injection sleeve 24. The pouring speed from the ladle 66 to the injection sleeve 24 becomes very slow.

The molten metal buffer plate 62 is for temporarily receiving the molten metal 68 poured from the ladle 66, and its setting position.
When H2 is less than ⅕ of the height H1 of the injection sleeve 24, many bubbles are generated in the poured molten metal 68 because the molten metal 68 drop from the pouring position of the ladle 66 to the molten metal buffer plate 62 is large. As a result, the oxide 70 is more entangled. Further, the height H2 of the molten metal buffer plate 62 is the height of the injection sleeve 24.
When it exceeds 4/5 of H1, since the molten metal 68 drop from the pouring position of the ladle 66 to the molten metal buffer plate 62 is small, the generation of bubbles in the molten metal 68 is small, but The height to 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. Therefore, the height H2 of the molten metal buffer plate 62 is ⅕ of the height H1 of the injection sleeve 24 before pouring the molten metal 68 into the injection sleeve 24.
4/5, preferably 2/5 to 3/5.

Further, the material of the oxide removing device 60 is, for example, a metal, a non-metal, or a composite material thereof which does not melt against the molten aluminum alloy or magnesium alloy. In the present embodiment, the molten metal buffer plate 62 and the moving shaft 64 are not limited to be orthogonal to each other as shown in FIG. 3, but the intersecting angle between the molten metal buffer plate 62 and the moving shaft 64 as shown in FIG. You may make it match with the inclination angle of. 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 configured as described above 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, as shown in FIG.
As shown in (3), the rod 52 of the tilt cylinder 44 is advanced and tilted to the chain line position, and the lubricant is spray-supplied to the injection sleeve 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 with the moving shaft 64 of the oxide removing device 60 being held by a holding device (not shown), and an annular gap 69 is formed between the molten metal buffer plate 62 and the injection sleeve 24. And position it to have
As shown in FIG. 3, the molten metal buffer plate 6 in the injection sleeve 24
The height H2 of 2 is, for example, 2/5 of the height H1 of the injection sleeve 24.
Position so that

Next, for example, an aluminum alloy molten metal 68 is pumped from a molten metal holding furnace (not shown) by a ladle 66, and then tilted on the injection sleeve 24, and once gently poured onto the molten metal buffer plate 62 having a small head difference. When molten metal starts, 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. 3). Molten metal 6
When 8 flows down from the annular gap 69 into the injection sleeve 24, the swirling flow of the molten metal 68 is made as slow as possible to prevent the entrainment of air, and also the entrainment of the distribution material 70 in the molten metal 68. Reduce.

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. 4). Molten metal 6 stored in the injection sleeve 24
8 As the molten metal buffer plate 62 gradually approaches the molten metal buffer plate 62, the molten metal buffer plate 62 is elevated while being careful that the molten metal buffer plate 62 is constantly positioned above the molten metal 68. Immediately before the completion of pouring into the injection sleeve 24, the rising of the molten metal buffer plate 62 is stopped, and the molten metal surface of the molten metal 68 is positioned slightly above the upper surface of the molten metal buffer plate 62 (FIG. 5).

When pouring is completed, the ladle 66 is ready to pump the molten aluminum alloy 68 into the molten metal holding furnace. On the other hand, when the molten metal buffer plate 62 is pulled up from the injection sleeve 24, the molten metal 68 is on the upper surface of the molten metal buffer plate 62, and the oxide 70 floating on the molten metal surface.
Are attached, and it is retracted to an appropriate position as it is (FIG. 6).
After this, the oxide 70 attached to the upper surface of the molten metal buffer plate 62
Are mechanically removed by collision, vibration, gas (including air) blowing, etc. in the next step.

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 tilt cylinder 44 to erect the injection device 13. Next, when pressure oil is introduced into the cylinder hole 30, the docking frame 22 starts rising at a predetermined degree of continuity, and brings 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. 2, and the molds 11 and 12 are opened to open the cavity 11
The cast product in a and 12a is taken out, but when the mold is opened, the product and the biscuit 71 are cut and separated, and one cycle is completed.

Next, the rectangular flat plate casting product (18 × 100 × 200 mm) obtained by the above-mentioned high-pressure casting method was cut in the vertical and horizontal directions to make 20 test pieces (18 × 50 × 20 mm). The amount of oxide 70 contained in the test piece was measured and Table 1
I got a result like.

The casting conditions and the conditions of the molten metal buffer plate 62 at the time of high pressure casting shown in Table 1 are as follows. Casting conditions: gate speed 50.0 mm / s injection sleeve inner diameter 80 mm (cross-sectional area ^{A2 = 50.2mm 2) A1 / A2} = 0.77 (-) melt pressure 800 kgf / cm ² cast product material; AC4CH (T6) melt Buffer plate condition: Molten metal buffer plate 70 mm (projected area A1 =
38.5mm ² ) Height from plunger tip surface (H2) 120mm Length from plunger tip surface to top of injection sleeve (H1) 210mm H2 / H1 = 0.57 (-)

[0026]

[Table 1]

In Table 1, the amount of oxide 70 mixed in the cast product obtained by the casting method according to the present invention is the value when the wire net 74 is attached to the gate 67 portion which has been conventionally performed (Comparative Example 1). It can be seen that it is less than or equal to. On the other hand, in the cases of Comparative Examples 3 and 4, it was found that the amount of oxide mixed in the cast product was large, which was almost the same as that of Comparative Example 2 in which the wire net was not attached to the gate 67 portion. The tensile strength (σ
B) and elongation (δ) become smaller.

The oxide amount (%) shown in Table 1 was calculated as follows. When observing the amount of oxide, a notch is formed in each test piece (18 × 50 × 20 mm) to form a fracture surface, and the fracture surface is used as an observation surface. The size of the oxide exposed on these observation surfaces is 1 mm or less, 1-2.
mm, 2 to 3 mm, and 3 to 4 mm, the number of oxides falling within these size ranges was visually observed, and the amount of oxides mixed in the cast product was calculated by the following formula.

[0029]

[Equation 1]

Here, Y is the total observation area of 20 test pieces,
X represents the amount (%) of oxide mixed in the cast product. In this embodiment, the case of horizontal vertical casting is described, but the present invention is not limited to this, and other methods such as vertical vertical casting can also be used.

[0031]

As is apparent from the above description, in the casting method for casting products with a small amount of oxides according to the present invention, the molten metal buffer plate having an annular gap between the vertical injection sleeves is used for the injection sleeves. It is fixed to the tip of the moving shaft that moves up and down coaxially with the injection sleeve and is poured at a suitable height inside the injection sleeve from above the injection sleeve toward the molten metal buffer plate. While flowing down, the molten metal buffer plate is raised in accordance with the molten metal surface rising speed, and the molten surface is positioned so as to be above the buffer plate before the completion of pouring, and the oxide remaining on the buffer plate By taking out integrally with the buffer plate, it is possible to prevent external air and oxides from being entrained in the molten metal, so that a cast product of extremely excellent quality can be obtained as compared with the conventional cast product. 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 front view of a vertical casting die casting machine.

FIG. 2 is a vertical cross-sectional view of a vertical injection device.

FIG. 3 is an explanatory diagram showing a state of pouring molten metal into the injection sleeve according to the embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a state of pouring molten metal into the injection sleeve according to the embodiment of the present invention.

FIG. 5 is an explanatory view showing a state of pouring molten metal into the injection sleeve according to the embodiment of the present invention.

FIG. 6 is an explanatory view showing taking out of an oxide obtained by a casting method according to an example of the present invention.

FIG. 7 is another embodiment similar to the present invention.

FIG. 8 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 mesh

Claims (1)

[Claims] 1. 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, and is positioned at an appropriate height inside the injection sleeve. In this state, the molten metal is poured from above the injection sleeve toward the molten metal buffer plate and then allowed to flow down from the annular gap.At the same time, the molten metal buffer plate is raised in accordance with the rising speed of the molten metal and melted before completion of pouring. A method for producing a cast product having a small amount of mixed oxide, wherein the surface is positioned above the buffer plate and the oxide remaining on the buffer plate is taken out integrally with the buffer plate.