JP2002254155A - Casting method and casting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a reliable and effective effect by a pressurizer, draw the pressurizer from a feeder head with a week force, and prevent sticking of a molten metal (solidified metal) to the tip of the pressurizer to inhibit the generation of a 'gall' between the tip and a sleeve. SOLUTION: In the casting device wherein a sleeve 4 is connected to a gate 3 of a metal mold, the pressurizer 5 is fit together by insertion into the sleeve movably forward/backward, a molten metal flow-in port 6 is provided at the midway part of the sleeve, after filling up the molten metal into a cavity 1 from the molten metal port with a low pressure, the molten metal in the cavity is pressurized with a low speed and by a high pressure by the pressurizer to carry out the casting, a fixed member 8 covering the tip 5a of the pressurizer is provided separably on the tip 5a of the pressurizer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting method and a casting apparatus in which a molten metal filled in a mold cavity is cast by applying pressure with a pressurizer to a molten metal. A casting method in which a pressurizer is pressed into the thick portion of the cast product in a state where the melt is solidified to a certain extent to perform casting (this is referred to as a local pressure casting method). The present invention relates to a casting apparatus in which a molten metal in a cavity is cast at a low speed and a high pressure by a pressurizer after being filled.

[0002]

2. Description of the Related Art Products cast by this type of casting method (local pressure casting method) and casting equipment have almost no casting cavities (pinholes) inside, and have a clean casting surface and excellent dimensional accuracy. At the same time, it has excellent features such as a finer structure and improved mechanical properties. However, as a practical problem, it is very difficult to determine the timing of pressurization (pressing water) by the pressurizer, and if the timing of pressurization deviates, the pressurizing effect of the pressurizer cannot be sufficiently exhibited.

[0003] Accordingly, the present applicant has previously described, as shown in FIG.
The inside diameter of the gate 3 of the mold (the fixed mold 2a and the movable mold 2b) is formed to be larger than the outer diameter of the pressurizer 5, and the pressurizer 5 is allowed to enter the inside of the sprue 3. (Japanese Patent Application Laid-open No. Hei 9-1997)
155530). According to this casting method, when the pressurizing element 5 enters the inside of the gate 3, there is an appropriate space L between the outer circumference of the pressurizing element 5 and the inner circumference of the gate 3, so that the pressing element 5 Even if the timing of the pressure (pusher) shifts and the molten metal inside the gate starts to solidify from its outer periphery,
It has become possible to expect a reliable and effective hot-water effect by the pressurizing element.

[0004]

However, if an appropriate space is provided between the outer periphery of the pressurizer and the inner periphery of the gate section as in the above-mentioned conventional example, it is necessary to pressurize the molten metal in the cavity. When the pressurizer enters the inside of the sprue part, the molten metal in the feeder part (inside the sprue part) solidifies and shrinks and is held on the outer periphery of the pressurizer. A strong pulling force is required to return to the position. This not only requires a large drive cylinder to operate the pressurizing element, but also causes the hot water portion connected to the product section to be unable to be pulled out of the pressurizing element and to fail in taking out the product.

[0005] On the other hand, when the casting is repeated, the molten metal (solidified metal) gradually adheres to the tip of the pressurizer, and "galling" may occur with the sleeve. If the molten metal (solidified metal) adheres to the pressurizing element and "galling" occurs, the pressure applied to the molten metal fluctuates, causing a variation in product quality. By the way, the situation where the molten metal solidifies and shrinks, causing it to cling to the outer periphery of the pressurizer or causing the galling to occur due to the local pressurization casting method, in which the pressurizer is pressed into the thick part of the product in the cavity and cast. (Hereafter simply referred to as “local pressure casting method”
Called. )), In which case the pressurizing element is
"Galling" occurs with the mold.

[0006] The "galling" caused by the increase of the drawing force caused by the molten metal in the pusher portion being held on the outer periphery of the pressurizer and the adhesion of the molten metal (solidified metal) to the pressurizer.
Although some problems such as the occurrence of cracks can be alleviated by applying a lubricant to the outer circumference of the pressurizer, applying the lubricant to the outer circumference of the pressurizer mixes the applied lubricant into the molten metal and adversely affects the product. Therefore, not only excessive use but also use itself is not very preferable.

The present invention has been made in view of such a problem, and it is possible to expect a reliable and effective feeder effect by the pressurizing element. It can be pulled out with a small force from the inside of the sprue, and the molten metal (solidified metal)
It is an object of the present invention to provide a local pressure casting method and a casting apparatus which can prevent the occurrence of "galling" by preventing the adhesion of the steel.

[0008]

In order to achieve the above object, the local pressure casting method according to the present invention provides a pressurizing device in a thick portion of a cast product in a state where a molten metal filled in a mold cavity is somewhat solidified. In the casting method in which the discarding member is pushed in, the discarding member is provided at the tip of the pressurizer so as to be separable, and the discarding member is pushed into the product thick portion. Claim 1). Further, the casting apparatus of the present invention connects the sleeve to the gate of the mold,
A pressurizing element is inserted into the sleeve so as to be able to advance and retreat, and a molten metal inlet is provided in a middle part of the sleeve. In a casting apparatus for casting a molten metal in a cavity by advancing at a low speed and a high pressure, the tip of the pressurizer has an outer diameter substantially equal to the inner diameter of the sleeve, and covers the tip of the pressurizer. The placing member is provided so as to be separable (claim 2).
At this time, in order to prevent the molten metal from coming into direct contact with the tip of the pressurizing element, the molten metal in the feeder portion (in the thick part of the product or inside the sprue) solidifies and shrinks and is held around the outer periphery of the tip of the pressing element. In order to prevent this, the pressurizing element is formed into a substantially cylindrical shape or a substantially cup-like shape which covers the outer periphery of the tip (Claim 3), or enters the inside of the gate portion of the mold prior to the pressurizing element to form the mold. It is preferable that the molten metal in the cavity is formed in a substantially cylindrical shape having a length capable of being pressed (claim 4). In addition, as the disposal member, the disposal member is made of the same type as the cast metal so that it is compatible with the product even if the disposal member is cast into the feeder portion, or is easily regenerated as a return material together with the feeder portion. It is preferable to be formed of a metal material (claim 5).

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings, but the present invention is not limited to the illustrated embodiment. FIG. 1 is a schematic cross-sectional view for explaining an embodiment of a local pressure casting method in which a pressurizer is pushed into a product thick portion. FIGS. 2 to 5 show an embodiment of a casting apparatus for casting at low speed and high pressure. For the sake of simplicity, the same components will be denoted by the same reference symbols throughout the drawings, without redundant description.

Reference numeral 1 in the figure denotes a mold cavity for molding a product, which is formed by a pair of fixed mold 2a and movable mold 2b that open in the horizontal direction on the drawing, and fills the cavity 1 with molten metal. Then, the product S is cast by pressing. However, in particular, when a local pressure casting method is performed, a portion of the product S is formed into a wall having a thickness greater than that of the other portion as illustrated in FIG. A thick portion S 'is formed. As shown in FIGS. 2 to 5, a sleeve 4 is connected to the mold gate 3 communicating with the cavity 1 in a communicating manner, and the cavity 1 is filled with molten metal from the sleeve 4 through the mold gate 3. It has become so.

A pressurizer 5 is inserted into the sleeve 4 so as to be able to advance and retreat toward the gate 3 of the mold (the fixed mold 2a and the movable mold 2b), and a molten metal inlet 6 is formed in the middle part. The molten metal supply pipe 7 is connected to the inflow port 6. The molten metal supplied from the molten metal supply pipe 7 is filled at a low pressure into the mold cavity 1 from the inside of the sleeve 4 through the sprue portion 3 of the mold, and the pressurizer 5 is moved forward to the inside of the mold sprue portion 3 to move the cavity. The product is cast by pressurizing the molten metal M in 1 at low speed and high pressure.

The pressurizer 5 is for applying a predetermined casting pressure to the molten metal M filled in the cavity 1 from inside the gate 3 of the mold, and a sleeve 4 connected to the gate 3 of the mold. The mold (movable mold 2a side)
The drive cylinder (not shown) provided at the lower part of the slab 3 is installed so as to move forward and backward toward the inside of the gate 3. At this time, the top dead center of the pressurizer 5 is appropriately set between the position immediately before the mold gate 3 and the inside of the gate 3, and the bottom dead center is set to the sleeve 4.
(See FIG. 3). When the local pressure casting method is performed, as shown in FIG. 1, a pressurizer (also referred to as a pressure pin in the local pressure casting method).
Reference numeral 5 denotes a mold (fixed mold 2a or movable mold 2) at a position corresponding to the portion where the product thick portion S 'is formed in the cavity 1.
In the insertion hole 10 formed over the cavity 1 from the back side of b), it is installed so as to be able to protrude and retract toward the cavity 1.

Further, a disposal member 8 for covering the distal end 5a of the pressurizer 5 is provided at the distal end 5a of the pressurizer 5 so as to be separable. When the molten metal M in the mold gate 3 (the product thick portion S ′ in the local pressure casting method, the same applies hereinafter) is pressed by the pressurizer 5, the discarding member 8 is located at the tip 5 a thereof. Outer peripheral surface 5
This is for covering the distal end portion 5a of the pressurizer 5 so that the molten metal does not directly contact the a ′ or the distal end surface 5a ″. The sleeve 4 (the insertion hole 10 in the case of the local pressure casting method, the same hereinafter). ) Is formed in a substantially cylindrical shape, a substantially cup shape, or a substantially columnar shape having substantially the same outer diameter as the inner diameter, and is disposed on the tip end portion 5a of the pressurizer 5 in a separable manner.

That is, the outer peripheral surface 5a 'of the tip 5a of the pressing element 5
In order to prevent the molten metal from coming into direct contact with the sleeve, the discarding member 8 should have an outer diameter substantially equal to the inner diameter of the sleeve 4 (insertion hole 10) and a length substantially equal to the pushing stroke of the tip 5a of the pressurizer 5. When it is formed in a substantially cylindrical shape and is separably installed on the outer periphery of the distal end portion 5a of the pressurizer 5, and when the molten metal does not directly contact the entire surface including the distal end surface 5a ″ of the pressurizer 5 Is formed in a substantially cup shape or a substantially cylindrical shape having substantially the same outer diameter as the inner diameter of the sleeve 4 (insertion hole 10) and substantially the same length as the pushing stroke of the tip 5a of the pressurizer 5. The separation member 8 of the illustrated embodiment has an outer diameter that is substantially the same as the inner diameter of the sleeve 4 (insertion hole 10) and is separated from the tip 5a of the pressurizer 5. Tip It is obtained by forming into a substantially cup-shaped having substantially the same length as the push stroke of a.

When the discarding member 8 is formed in a substantially cylindrical shape, it enters the mold gate 3 (the product thick portion S ') prior to the pressurizer 5 and enters the cavity 1. The length that can pressurize the molten metal M, that is, enters the inside of the mold gate 3 (product thick portion S ') instead of the tip 5a of the pressurizer 5, and enters the gate 3 (product thick portion S'). The molten metal M is formed so as to be pressurized from the inside thereof, and is installed so as to be separable on the distal end surface 5a ″ of the distal end portion 5a of the pressurizer 5. In this case, the top dead center of the pressurizer 5 is set to the mold gate 3 ( Set to the position immediately before the product thick part S '),
Even if the tip 5a of the pressurizing element 5 does not enter the inside of the mold gate 3 (the product thick part S ') at all, only a very small amount is required.

Here, when the tip 5a of the pressurizer 5 is pulled out from the hot water portion (the product thick portion S 'or the inside of the sprue portion 3) after the molten metal M is pressurized, the discarding member 8 is pushed by The tip 5 of the pressurizing element 5 is cast so as to remain in the hot water portion.
a so as to be separable. In this case, the discarding member 8 is made of the same kind as the cast metal so that the caster does not adversely affect the product even if it is cast into the feeder, or can be recycled together with the feeder. It is preferable to use a metal material.

The mold gate 3 (the product thick portion S ')
Is formed so that the inner diameter thereof is slightly larger than the outer diameter of the pressurizer 5 so that the inner peripheral surface of the gate 3 and the outer peripheral surface 5a of the tip 5a of the pressurizer 5
An appropriate distance L (for example, about 2 mm to 10 mm in the case of the sluice portion 3) is formed between the gate electrode a and the a ′.

When a product is cast by the local pressure casting method, when the molds (the fixed mold 2a and the movable mold 2b) are in the mold open state, the disposal member 8 is removed from the cavity 1 side. In a state where the melt of the product thick portion S ′ in the cavity 1 is somewhat solidified, the pressurizer 5 is pushed into the product thick portion S ′ by setting it in advance so as to be separable at the tip 5a of the pressurizer 5. The solidification shrinkage of the product thick portion S 'is compensated for. Then, after the molten metal in the product thick portion S ′ is solidified, the pressurizer 5 is pulled out, the mold is opened, and the product S is taken out from the cavity 1.

When a product is cast by the casting apparatus shown in FIGS. 2 to 5, a mold (fixed mold 2a, movable mold 2b) is used.
When is in the mold open state, the disposal member 8 is previously set to be separable from the sleeve 4 to the distal end portion 5a of the pressurizer 5 (see FIG. 3). Discarded member 8 at tip 5a of pressure element 5
Is set and the molds (the fixed mold 2a and the movable mold 2b) are closed, and the molten metal is supplied from the molten metal supply pipe 7 to the molten metal inlet 6 →
Inside the sleeve 4 → through the gate 3 into the cavity 1
The supply is filled at a low pressure (for example, about 0.01 MPa to 0.1 MPa) (see FIG. 4A). After that, pressurizer 5
Toward the gate 3 of the mold at a low speed (for example, 0.05 m /
(Approximately 0.2 to 0.2 m / sec), and the distal end portion 5a of the pressurizing element 5 is pushed into the inside of the mold gate 3 to enter. Then, the molten metal M filled in the cavity 1 is pressurized through the molten metal filled in the sleeve 4 or the sprue portion 3, and the product is cast (see FIG. 4B).

Then, after a predetermined curing time has elapsed, the molten metal M filled in the cavity 1 and the inside of the sprue portion 3 solidifies, so that the mold (fixed mold 2a, movable mold 2b)
While opening the mold, press the pressurizing element 5 with hot water (gate 3
From the inside of the mold) and return to the original position (see FIG. 5).
The discarding member 8 taken out from b) and cast into the feeder portion is regenerated together with the feeder portion as a return material. In addition, the throw-away member 8 installed at the tip 5a of the pressurizer 5 has a length capable of entering the inside of the mold gate 3 prior to the pressurizer 5 and pressurizing the molten metal M in the cavity 1. It is to be understood that when formed in a substantially cylindrical shape, the tip 5a of the pressurizer 5 does not enter the inside of the sprue 3 at all, or even enters the gate 3 very little.

[0021]

As described above, the local pressure casting method and the casting apparatus according to the present invention are provided with a disposal member for covering the distal end of the pressurizer at the distal end of the pressurizer. The placing member can expect a reliable and effective hot-water effect without impairing the hot-water action by the forward movement of the pressurizing element. When the molten metal is pressurized, the molten metal (solidified metal) adheres to the distal end of the pressurizer even after repeated casting because the molten metal does not directly contact the distal end of the pressurizer covered with the disposal member. As a result, the occurrence of "galling" due to the adhesion of the molten metal (solidified metal) to the sleeve can be suppressed.

Moreover, even if the hot water portion (the thick part of the product or the inside of the sprue portion) solidifies and contracts, only the discarding member is removed, so that the discarding portion is provided at the tip of the pressurizer so as to be separable. In combination with the above, the pressurizing element can be pulled out from the hot water part (the inside of the product thick part or the sprue part) with a weak force. Therefore, it is possible to pull out the pressurizing element (the front end part thereof) with a weak force from the hot water part (the inside of the product thick part or the sprue part) without applying the lubricant to the outer periphery of the front end part of the pressurizing element.

In addition, according to the casting apparatus of the third aspect of the present invention, the disposal member is formed in a substantially cylindrical shape or a substantially cup shape covering the outer periphery of the distal end portion of the pressure element. When the tip is advanced to the inside of the sprue to press the molten metal in the cavity, the molten metal does not come into direct contact with the outer periphery of the tip of the pressurizer. Is solidified and shrunk, and is caught on the outer periphery of the disposal member. Therefore, it is possible to reliably pull out the pressurizing member from the hot water portion (the inside of the product thick portion or the sprue portion) with a small force without applying a lubricant to the tip portion of the pressurizing member. It is possible to prevent the molten metal (solidified metal) from adhering to the outer periphery of the distal end portion and to suppress the occurrence of “galling” with the sleeve.

Further, according to the casting apparatus according to the fourth aspect of the present invention, the disposal member has a length capable of entering the inside of the mold gate before the pressurizing member and pressurizing the molten metal in the cavity. Since it is formed in a substantially cylindrical shape having the same, when the molten metal in the cavity is pressurized, the tip of the pressurizer does not enter the mold gate at all or becomes very small even when it enters, so that the pressurizer The molten metal does not directly contact the outer periphery of the tip. Therefore, even if a lubricant is applied to the outer periphery of the pressurizing element, there is no fear that the cast product is adversely affected, and
Even if the casting is repeated, there is no fear that molten metal or solidified metal will adhere to the tip of the pressurizer, and there is almost no fear that "galling" will occur with the sleeve.

According to the casting apparatus of the fifth aspect of the present invention, since the discarding member is formed of the same kind of metal material as the cast metal, the discarding member can be cast on the thick part of the product or the riser. Even if it is inserted and integrated, there is no fear that it will adversely affect the cast product, and it can be recycled as a return material together with the hot water.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view illustrating a local pressure casting method according to the present invention.

FIG. 2 is a front view of an apparatus showing an example of an embodiment of a casting apparatus according to the present invention.

FIG. 3 is an enlarged cross-sectional view taken along the line (X)-(X) of FIG. 2, showing a state in which a mold is opened and a disposal member is set on a distal end portion of a pressing element.

4A is a cross-sectional view showing a state in which a mold cavity is filled with a molten metal, and FIG. 4B is a cross-sectional view showing a state in which the molten metal in the mold cavity is being pressed by a pressurizer.

FIG. 5 is a cross-sectional view showing a state in which the pressurizer is pulled out from a hot water part (inside of a sprue part).

FIG. 6 is an enlarged sectional view illustrating a conventional example.

[Explanation of symbols]

S: Cast product S ': Product thick part 1: Cavity 2a: Fixed type 2b: Movable type 3: Gate section 4: Sleeve 5: Pressurizer 6: Molten inlet 7: Molten supply pipe 8: Discarding member

Claims (5)

[Claims] In a casting method in which a molten metal filled in a mold cavity is somewhat solidified, a pressing element is pressed into a thick portion of a cast product, and a disposal member is disposed at a tip of the pressing element. A casting method, wherein the casting member is provided so as to be separable and the discarding member is pushed into the thick part of the product. 2. A sleeve is connected to the gate of the mold,
A pressurizing element is inserted into the sleeve so as to be able to advance and retreat, and a molten metal inlet is provided in the middle of the sleeve. After the molten metal is filled from the molten metal inlet into the cavity at a low pressure, the pressure element is directed toward the spout. In a casting apparatus for casting a molten metal in a cavity by moving it forward at a low speed and a high pressure, the distal end of the pressurizer has an outer diameter substantially equal to the inner diameter of the sleeve, and covers the distal end of the pressurizer. A casting apparatus, wherein a placing member is provided so as to be detachable. 3. The casting apparatus according to claim 1, wherein the discarding member is formed in a substantially cylindrical shape or a substantially cup shape that covers an outer periphery of a distal end portion of the pressure element. 4. The discarding member is formed in a substantially cylindrical shape having a length capable of entering the inside of the gate and pressing the molten metal in the cavity prior to the pressurizing element. Or the casting apparatus according to 2. 5. The casting apparatus according to claim 1, wherein the discarding member is formed of a metal material of the same kind as the cast metal.