JPH0563259B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a mold for aluminum or an aluminum alloy, and more particularly to a mold for obtaining a perforated ingot of these metals and a pouring device therefor. It is.

[Prior Art] For example, aluminum or aluminum alloy is once melted in a melting furnace and adjusted to a predetermined composition.
It is manufactured into ingots weighing between 5Kg and 10Kg.
This ingot is melted in a melting furnace and poured into a predetermined mold to create a cast product, or after being melted and held in a melting furnace or holding furnace, the molten metal is pushed into a precision mold at high pressure and high speed to create a die-cast product. Light alloy products are obtained by

Normally, when manufacturing cast products and die-cast products, ingots weighing between 5Kg and 10Kg are often used, but when melting ingots in a melting furnace, it is necessary to melt quickly and save energy. It is. However, even if the ingot weighs 5 kg, its size is approximately 600 x 90 x 40 mm, and the melting time is long and the unit cost of energy is high. Furthermore, as the dissolution time increases, the oxidation loss also increases in proportion.

In order to shorten the melting time of the ingot, it has been proposed to break the ingot into several pieces or to make holes in the ingot. If we compare the melting times of the perforated ingot and the non-perforated ingot, it is obvious that the perforated ingot has a larger surface area, has more parts in contact with the melting heat atmosphere, and is therefore easier to melt.

[Problems to be Solved by the Invention] Perforated ingots have a short melting time and can easily achieve the goal of energy saving, but there are various problems when producing the ingots.

That is, in order to produce a perforated ingot, the following steps must be followed.

(1) Make a mold with a convex part corresponding to the perforated part.

(2) Attach this mold to a continuous casting machine.

(3) Next, pour molten metal into this mold.

(4) After pouring, in some cases, it is cooled with water and removed from the mold.

In this case, when the ingot is poured into a mold without protrusions and cooled, when the mold is turned over in a continuous casting machine, the ingot product smoothly falls away from the mold under its own weight. On the other hand, in a mold having convex portions, the ingot does not separate from the mold even if the mold is turned over in a continuous casting machine after pouring and cooling. The reason why the ingot does not easily separate from the mold is that the convex parts of the mold are symmetrical in the longitudinal direction of the mold and in the direction orthogonal to this, and the molten metal solidifies and cools inside the mold. This is because it is related to contraction during the process. As a result, the protrusions obstruct the shrinkage margin, and tensile stress remains in the ingot even after cooling, and stress acts on each protrusion toward the center of the mold, causing the ingot to move around each protrusion. This creates a jammed state, making it extremely difficult for the ingot to separate from the mold.

[Means for Solving the Problems] The present invention solves the above-mentioned problems, and in producing a perforated ingot that melts quickly and has an energy-saving effect, the ingot can be removed from the mold simply by reversing the mold. To provide a mold that is extremely easily removed.
Furthermore, we also propose a casting device that allows the molten metal to circulate well within the mold and produce a uniform ingot despite the presence of convex portions when pouring into the mold. Specifically, in the convex portion disposed in the mold, the slope angles of both slopes in the length direction of the mold are different, and the slope angle of the slope surface on the side closer to the mold center is steeper, and the slope angle on the side farther from the mold center is steeper. The slope angle of the side slope surface is gentle. Furthermore, the slope surface with a gentle slope angle has a slope angle that is gentler in the part near the top of the mold than in the part near the bottom of the mold.
It is a multi-stage gentle slope surface or a compound slope surface with gradually decreasing curvature. By forming such a convex portion, the convex portion was prevented from being bitten by the solidified ingot. Furthermore, when pouring into the mold having the plurality of convex parts, each convex part is poured so that the area around the molten metal is evenly divided into each part, and a homogeneous ingot without any melt spots or spots is obtained. The present invention provides a pouring device for dispensing molten metal into the middle of a section.

Therefore, the present invention provides a mold having a convex portion inside for obtaining a perforated ingot, in which the convex portion provided in the mold is formed into a conical shape, and the convex portion has both inclined surfaces in the longitudinal direction of the mold. The inclination angles of the two are different. Furthermore, of the two different sloped surfaces, the sloped surface on the side farther from the center of the mold is made gentler, and the slope becomes gentler as it approaches the top of the convex portion, forming a composite sloped surface.

Furthermore, in a pouring device for a mold having a plurality of convex portions inside the mold, pouring ports for pouring molten metal equal to the number of intervals between the convex portions inside the mold are placed facing each of the intervals between the convex portions. Molten metal is poured into the mold of the above-mentioned invention using a pouring device having the following configuration, which is installed in a molten metal rotary distributor.

OPERATION OF THE INVENTION Metallurgically, a metal or alloy has a certain temperature at which solidification begins and completes. Once solidification is complete, a unique spatial lattice is created, and the metal structure does not change even if a certain amount of force is applied thereafter. Therefore, considering the solidification completion point, for example, even if the mold temperature is high or the pouring temperature is high, assuming that a normal mold is filled with metal and the feeder is sufficiently pumped, the molten metal will solidify. The parts that are about to shrink are filled with metal one after another, and they do not shrink until solidification is complete.

However, when the metal is poured into one mold and there is no feeder, such as in the case of ingot molds, the metal shrinks from the melting point depending on the composition of the metal to the completion of solidification. Then, from the point of completion of solidification, it also contracts during cooling to room temperature. The poured metal shrinks in multiple stages. On the other hand, a mold only expands and contracts repeatedly due to temperature differences in the solid, and the expansion and contraction allowances are smaller than that of poured metal.

Furthermore, in the mold provided with the convex portion according to the present invention,
As shown in Figure 4, the molten metal solidifies at the center of the mold 3.
It progresses while shrinking towards . Therefore, mold 1
A contraction L in the length direction of the mold 1 and a contraction S in the direction perpendicular to the length direction of the mold 1 occur, but the former mold 1
The shrinkage L in the longitudinal direction of the latter is much larger than the shrinkage S in the orthogonal direction of the latter, and the shrinkage L in the longitudinal direction governs the shrinkage behavior during solidification. To deal with this,
As shown in FIG. 5, the convex part of the mold of the present invention has a steeply sloped surface 12 on the side closer to the mold center 3 and a gentle slope on the side farther from the mold center 3, and is closer to the top than the part near the mold bottom. The slope is gentler.

When molten metal is poured into the mold 1 having such a convex portion 2 up to the low melt level 4, the shrinkage margin occurs only horizontally, and the resultant force C of the horizontal component D and the vertical component B of the horizontal stress A is Since the horizontal stress A is applied to the one slope surface 22 and remains, the cast product becomes difficult to come out of the mold. However, if the slope near the top of the convex part 2 is made gentler and the molten metal is poured to the hot melt level 5, the resultant force C of the horizontal component D of the horizontal stress A and the vertical component B will be Nearby even gentler second slope surface 32
It acts more upwards. As a result, the solidification of the molten metal in the mold of the present invention shrinks toward the mold opening surface, and the convex portion 2 in the mold 1 is not bitten. Furthermore, for the sloped surface 12 of the convex portion 2 on the side closer to the mold center 3, shrinkage during solidification of the molten metal tends to move away from this sloped surface 12, so there is no need to create a multi-stage gentle slope and the slope is straight. The slope may be as steep as .

Thus, in the mold of the present invention, when the poured molten metal solidifies, by inverting the mold so that it faces downward, the ingot can easily separate from the mold by its own weight alone.

In addition, in order to pour metal into a mold that exhibits such action, the molten metal is poured from the tapping trough into a rotary distributor having a pouring spout, and the amount of molten metal that flows out from the pouring spout intermittently as the rotary distributor rotates. Molten metal is poured into individual molds by matching the internal volume of the mold moving directly beneath it. In this case, the rotary distributor does not have one pouring port as in the conventional example,
According to the present invention, in which a plurality of protrusions are installed in a mold so as to face the spaced portions thereof, the flow of molten metal is not hindered by the protrusions and is uniformly diffused into the mold.

[Example] Hereinafter, a specific example of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 to 5, in the present invention, a mold 1
A convex portion 2 is disposed inside the convex portion 2, and the convex portion 2 has a specific shape.

That is, each convex portion 2 is formed in the shape of a cone, and both sloped surfaces in the longitudinal direction of the mold 1 have different inclination angles, and the sloped surface on the side closer to the mold center 3 is a steep sloped surface 12. In the illustrated embodiment, the slope surface on the side far from the mold center 3 is a first gentle slope surface 2.
2 and a second gentle slope surface 32 that is gentler than the first slope surface are continuous. In this embodiment, the steeply sloped surface 1 of the convex portion 2 on the side closer to the mold center 3
2 has a slope of 74 degrees to the mold bottom. In addition, the two-stage sloped surface on the side far from the mold center 3 has a first gently sloped surface 22 that is in contact with the mold bottom at an angle of 36 degrees with respect to the mold bottom, and a second gently sloped surface 32 that is continuous with the first gently sloped surface 22 that is in contact with the mold bottom. The slope was 15 degrees.

Note that 6, 6' and 6'' are ribs for reinforcing the mold.

It goes without saying that the protrusion 2 provided in the mold 1 may be made of the same material as the mold 1;
As shown in the figure or FIG. 7, the convex part is mold body 1' (the part of the mold 1 excluding the convex part, the same applies hereinafter).
It can be removably attached to the Such an embodiment is advantageous because the convex portion can be made of a different material from the mold body. In this embodiment, after the mold body is manufactured, the above-mentioned convex portion having a specific shape is attached to the mold body, and as shown in FIG. It is attached to the mold body using an attachment part 7 made of a material with a large coefficient. Further, the convex portion 2″ shown in FIG.
Mounting part 7' made of metal with high elasticity when receiving heat
It is attached to the mold body using. The protrusions 2' or 2'' attached to the mold body via these attachment parts 7 or 7' move forward, backward, left and right along the length of the mold due to the temperature rise when molten metal is poured into the mold 1. This makes it possible to move about 1 to 3 mm in the direction perpendicular to the bottom of the mold, thereby alleviating the shrinkage stress applied to the convex portion when the molten metal solidifies.

Furthermore, the mechanical strength of the protrusions 2 disposed inside the mold 1 decreases when the mold 1 is held at a temperature 100 to 200°C lower than the freezing point (substantially the melting point) of the molten metal applied to the mold 1 for 3 minutes. The convex portion 2 can be formed using a material that dissolves or disappears. In particular, the type of protrusion that disappears after being held at a predetermined temperature is, for example, made of foamed polystyrene and silica sand.
Kibushi clay is kneaded into a predetermined shape, and a paint containing particulate boron nitride as a lubricating mold release agent dispersed in a solvent is applied to the surface of the convex portion.

The convex portion in such an embodiment needs to be attached to the mold body each time molten metal is poured into the mold 1.

In another embodiment, the inclined surface on the side far from the mold center 3 in the convex portion 2 is made gentle and is formed into a compound inclined surface, but the degree of inclination of the gentle inclined surface can be set to three or more stages. Furthermore, the same effect can be achieved by using a curved slope whose curvature gradually decreases from the base to the top of the convex portion, instead of making the degree of inclination of the gently sloped surface step-like. As described above, the slope on the side near the mold center 3 may be steep, and may be perpendicular to the mold bottom.

The ingot 10 having a uniform metal structure can be obtained by pouring into the perforated ingot mold according to the above embodiments using the rotary distributor 40 having a plurality of pouring ports 41. In the embodiment shown in FIG. 8, a rotary distributor 40 is formed by arranging a plurality of pouring ports 41 on a line parallel to the axis on the circumferential surface of a rotary drum body having a horizontal rotation axis. be. This rotary distributor 40 is rotated in the R direction, and molten metal 43 is injected from an opening at one end via a tapping gutter 42.

The rotary distributor 40 rotates in the R direction at a constant speed, and when the plurality of pouring ports 41 arranged in series turn to the lower part, the molten metal 43 inside begins to flow out, and when the plurality of pouring ports 41 arranged in series turn to the upper part through the lowest part, the pouring ports The outflow of molten metal from 41 is stopped. During this time, the mold 1 placed on the conveyor is moved by the distance between the outflow start part and the outflow stop part of the molten metal 43, and the amount of molten metal poured into the mold 1 is adjusted to obtain the required ingot. A casting apparatus is obtained in which it is possible to control the amount of molten metal introduced from the tapping trough 42 so that the amount of molten metal is controlled.

The number of pouring ports 41 disposed in the rotary distributor 40 included in the casting apparatus is equal to the number of intervals between the plurality of convex portions 2 provided in the mold 1 of this embodiment, and We will have each of them face each other.

[Effects] In the above embodiment, the shape of the convex portion installed in the mold satisfies certain conditions, and the casting device is a rotary distributor having a plurality of pouring ports, thereby achieving the following effects. Obtained.

That is, (a) In the perforated ingot mold according to the embodiment of the present invention, the ingot after pouring and solidification can be easily removed from the mold simply by reversing the mold.

(b) If there are multiple convex portions provided in the mold,
Since the molten metal is simultaneously poured from a plurality of pouring ports into the spaced portions of each convex portion, the molten metal flows well and an ingot with a homogeneous metal structure in each portion is obtained.

[Brief explanation of the drawing]

1 to 3 show a mold according to an embodiment of the present invention, FIG. 1 is a plan view, FIG. 2 is a longitudinal sectional view taken from the side shown in FIG. 1, and FIG. 3 is a cross-sectional view taken from the side shown in FIG. FIGS. 4 and 5 are explanatory diagrams showing the function of the mold of the present invention, and FIGS. 6 and 7 are sectional views of main parts of other embodiments. FIG. 8 is an explanatory cross-sectional view of a casting apparatus in an embodiment of the present invention. 1... Mold, 2, 2', 2''... Convex portion, 3... Center of mold, 4... Low melt level, 5... High melt level, 7, 7'
... Mounting part, 10 ... Ingot, 12 ... Steep slope,
22...first gentle slope surface, 32...second gentle slope surface,
40...Rotary distributor, 41...Pouring spout, 42...
Outlet gutter, 43...molten metal.

Claims (1)

[Scope of Claims] 1. In a mold having an internal convex portion for obtaining a perforated ingot, the convex portion provided in the mold is formed into a conical shape, and both sides of the convex portion in the longitudinal direction of the mold are A perforated ingot mold characterized by having sloped surfaces with different inclination angles. 2 Among the sloped surfaces with different slope angles of the convex portion provided in the mold, the sloped surface on the side far from the center of the mold has a gentler slope angle, and the slope near the top is greater than the slope of the part near the bottom of the mold. 2. The perforated ingot mold according to claim 1, further comprising a convex portion having a gentle compound slope. 3. In a pouring device for a mold having a plurality of convex portions inside the mold, a molten metal pouring port equal to the number of intervals between the convex portions in the mold is placed so as to face the interval between the convex portions, respectively. A pouring device for perforated ingots, which is installed in a rotary distributor, and is characterized by: