JPH0798256B2 - Ladle for die casting - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ladle for drawing out a molten metal kept in a holding furnace of a die casting machine and supplying it to a casting cylinder.

2. Description of the Related Art In a gold chamber die casting machine, a molten metal kept warm in a holding furnace is pumped out by a ladle and supplied to a casting cylinder (cold chamber), and the molten metal is pressed into a mold by a plunger to cast a product. At this time, the die casting ladle is made of cast iron.

Problems to be Solved by the Invention However, the cast iron die casting ladle as described above is eroded by the molten metal, and there is elution of iron or the like into the molten metal, which is mixed as an impurity in the product and adversely affects the material. Exert. Some die-cast ladle surfaces have corrosion resistant ceramic powder applied as an anticorrosion agent to prevent erosion by the molten metal, but their adhesion is weak, so they should be used together when peeling off the molten aluminum deposits. It is necessary to peel it off and reapply it many times, which requires man-hours for maintenance and inventory control. In addition, there is also a cradle made from a single Si ₃ N ₄ system ceramic in consideration of erosion by molten metal. However, this ladle was produced by reaction sintering
Since it is a Si ₃ N ₄ type ceramic, its bending strength is at most 30k.
It is about g / mm ² , and the strength is poor. For this reason, there is a method of increasing the thickness of the ladle to give it strength, but the size of the ladle itself is too large to be used as a substitute for the currently used cast iron ladle, and it is difficult to substitute it.

The present invention was manufactured by repeated studies in order to deal with the above-mentioned actual situation, and the purpose thereof is to make the material of the die casting ladle high density, high strength Si ₃ N ₄ series ceramic or sialon. By providing corrosion resistance and strength to the molten metal, smoothing the surface by densification to prevent the molten metal from adhering, and by providing a die casting ladle that does not require maintenance labor such as applying an anticorrosive agent. is there.

Means for Solving the Problems In order to solve the above problems, the present invention has a ladle of a holding furnace for a die casting machine, a bending strength of 50 kg / mm ² or more, and a density of 95% or more of a theoretical density in water. This is a die casting ladle made of Si ₃ N ₄ system ceramic or sialon having a thermal shock temperature of ΔT = 400 ° C. or more by a dropping method.

And Si ₃ N ₄ system ceramics or sialon have an α phase of 75
70% by weight or more of Si ₃ N ₄ containing 1% by weight or more, and 1% by weight or more and 10% by weight or less of an oxide of a group IIIa element of the periodic table, Al ₂ O ₃ 1
0 wt% and less, is obtained by sintering a mixture comprising AlN solid solution _{(AlN-Si 3 N 4 ·} Al 2 O 3 system) or AlN10 wt% or less.

Further, the Si ₃ N ₄ system ceramic or sialon has an α phase of 7
80% by weight or more of Si ₃ N ₄ containing 5% by weight or more, and 1% or more and 10% by weight or less of oxides of Group IIIa elements of the periodic table, Al ₂ O ₃ 1
A mixture of 0% by weight or less may be sintered.

Action By using the above-mentioned Si ₃ N ₄ system ceramic or sialon as the material of the die casting ladle, since it has corrosion resistance and high strength to the molten metal, it is not corroded by the non-ferrous metal molten metal, and even if it receives an impact load. It won't break. Further, since the surface is smooth due to the high density, it is possible to prevent the molten metal from adhering.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 (a) is a plan view of a die casting ladle according to an embodiment of the present invention, and FIG. 1 (b) is a front sectional view. Fig. 1 (a)
And as shown in (b), the die casting ladle 1 has a bowl shape and has a constant length, width, depth and wall thickness, and the constricted end 1a is fixed to the holder (not shown) at a constant angle. It is rotatably attached and draws out the molten metal kept warm in the holding furnace and supplies it to the casting cylinder of the die casting machine.

As the material of the die casting ladle 1, Si ₃ N ₄ system ceramic or sialon is used, the bending strength is 60 kg / mm ² , the density is 98% of the theoretical density, and the thermal shock temperature ΔT by the water immersion method is
= 500 ° C or higher. In addition, the Si ₃ N ₄ system ceramic or sialon contains 80% by weight or more of Si ₃ N ₄ containing 85% by weight or more of α phase, and one or more kinds of oxides of group IIIa elements of the periodic table.
% Or less, Al ₂ O ₃ 7% or less, AlN solid solution (AlN
-Si ₃ N ₄ · Al ₂ O ₃ system) or AlN 7% by weight or less is a mixture obtained by sintering.

As a result of using the die casting ladle 1 made of the above material in an aluminum holding furnace, almost no corrosion by the molten metal was observed, and it sufficiently withstood the impact load and thermal shock during use. Further, it has been found that the service life is greatly extended as compared with the conventional cast iron die casting ladle, the service life is longer than 1 year without maintenance, and it can be used almost semi-permanently unless there is an accident during use.

The material of the die casting ladle 1 is not limited to this embodiment. Other Si ₃ N ₄ based ceramics or sialon, for example, 80% by weight or more of Si ₃ N ₄ containing 85% by weight or more of α phase, and 1% or more and 7% by weight or less of oxides of Group IIIa elements of the periodic table. , A mixture of Al ₂ O _{3 and} 7 wt% or less may be sintered.

As described above, the present invention makes the material of the ladle of the holding furnace for the die casting machine high density, by using Si ₃ N ₄ system ceramic or sialon having high strength, the life of the die casting ladle is greatly increased. Not only can it be improved, but it also has the effect of eliminating the need for maintenance during use, eliminating adverse effects by avoiding the inclusion of impurities in the product, and enabling stable and favorable manufacture of the product. Industrially, its value is high.

[Brief description of drawings]

FIG. 1 (a) is a plan view of a die casting ladle according to an embodiment of the present invention, and FIG. 1 (b) is a front sectional view. 1 ... Ladle for die casting.

Claims (3)

[Claims] 1. A bending strength of 50 kg / mm ² or more, a density of 95% or more of the theoretical density, and a thermal shock temperature ΔT = 400 by the underwater dropping method.
A ladle for die casting, which is made of Si ₃ N ₄ system ceramic or sialon having a temperature of ℃ or higher. 2. The Si ₃ N ₄ system ceramic or sialon contains Si ₃ N _{4 in an amount of} 70% by weight or more containing 75% by weight or more of α phase, and 10% by weight or more of one kind of oxides of Group IIIa elements of the periodic table. % Or less, Al ₂ O ₃ 10% by weight or less, AlN solid solution (AlN-Si ₃ N ₄ · Al
₂ O ₃ series) or AlN 10 wt% or less is a mixture obtained by sintering.
Ladle for die casting according to the item. 3. The Si ₃ N ₄ type ceramic or sialon contains 80% by weight or more of Si ₃ N ₄ containing 75% by weight or more of α phase, and 10% by weight or more of one of oxides of Group IIIa elements of the periodic table. % And Al ₂ O ₃ 10% by weight or less are sintered, and the ladle for die casting according to claim 1 is characterized by being sintered.