JPH0577023A - Ceramic stoke for low pressure casting - Google Patents

Abstract

PURPOSE:To prevent the solidified stickiness by improving the heat insulating effect of a stoke itself, reducing the transferring heat radiation from an inside wall layer to prevent the heat in the stoke itself from lowering at the time of passing through and discharging molten metal. CONSTITUTION:In the ceramic-made stoke used at the time of executing pressurize-casting to the molten aluminum or aluminum alloy, this stoke is constituted with the inside wall layer 3 and an outside layer 4. Further, this has the peculiarity of multi-layer structure by arranging heat insulating material layer 2 composed of ceramic material and gap part 1 at this intermediate part. By forming the structure provide with the inside wall layer and the outside wall layer, and the heat insulating material layer part and the gap part at between these layers, the original performance is sufficiently held, and the stoke for low pressure casting being solvable to various problems, such as the secureness of the long service life and the safe operation, the improvement of the product quality and the yield, can be provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ceramic stalk for pouring metal used in a low pressure casting machine used for casting a molten aluminum or aluminum alloy.

[0002]

2. Description of the Related Art A low pressure casting machine casts a molten metal surface in a molten metal container such as a lower crucible into a mold installed in an upper portion to cast the molten metal.

The stoke is used as a pipe for connecting the molten metal in the molten metal container to the upper mold, that is, as a runner for casting the molten metal. What is used as this stalk material is generally a cast iron material, a titanium alloy material, or a material made of metal, which is provided as a protective film on the outer surface with a coating material of an inorganic material such as an oxide on the outer surface. A stalk made of ceramics produced by using a stalk, a silicon carbide-based material, or a silicon nitride-based material as a main raw material is used.

[0004]

However, the former has a high chemical reactivity with the molten metal, and the melt produced by the reaction is mixed as an impurity in the molten metal to deteriorate the quality, which causes a problem in quality and the service life. However, the replacement work becomes frequent and the working efficiency is adversely affected. The latter ceramic materials containing silicon carbide and / or silicon nitride as main components have been improved in terms of service life and inclusion of impurities in the molten metal due to the stalk material. The problem that occurs is that there is a phenomenon of adhesion of metal in the upper part of the inside that is the runway of the stalk, and these deposits cause turbulence during molten metal casting, This causes problems such as being mixed in and mixed in the casting.

The present invention is intended to solve the above-mentioned problems, and the cause of the adhesion is investigated by various investigations and researches.
Every time the surface of the molten metal is pressurized and cast, the molten metal in the stalk enters, exits, becomes full, or becomes empty. During this time, the temperature of Stoke lowers due to heat dissipation from Stoke itself. During the stalk in such a state, the molten metal is repeatedly flown and discharged (discharged) at every casting, so that the deposition and solidification of the molten metal are gradually repeated and a large amount of deposits are accumulated as the molten metal is accumulated. Become. Therefore, as described above, the flow of the molten metal during casting is disturbed, and the deposited deposits come off and intervene in the product, resulting in a reduction in work surface and quality and a reduction in product yield. It is the current situation that there is a strong desire to improve

[0006]

[Means for Solving the Problems] In view of the current situation, as a result of various researches and experiments to improve these problems, as a result, at least the portion exposed from the molten metal is in the stalk thickness direction (circumferential direction). (2) The inner wall layer is made into two layers, the outer wall layer, and a heat insulating material layer made of ceramic material and a void are provided between the two layers to increase the heat insulating effect of the stalk itself by providing the heat insulating material layer and the void. By reducing the radiation emitted from the inner wall layer, the flow of molten metal
The purpose is to prevent solidification and adhesion by preventing the heat of the stalk material itself from lowering during discharge.

The main purpose of the present invention is to provide a multi-layer structure with a heat insulating layer, a void, etc. inside the main body of the outer and inner two layers by reducing the heat radiation from the stalk itself to make the metal in the upper part of the stalk hole. For the purpose of suppressing adhesion and deposition, even if different materials are used in combination, no cracks are generated at the joint between the inner wall layer of the stalk and the outer wall layer due to the difference in coefficient of thermal expansion, etc. It is good, and it is good to be composed of the same material, and to integrally mold at the time of manufacturing,
The inner and outer wall layer materials may be manufactured separately and then joined. It may be manufactured by either method, but it has a multilayer structure in which a heat insulating material layer and a void portion are provided at least in a portion exposed from the molten metal inside the stalk circumferential direction.

Further, the multi-layered structural portion configured to enhance the heat insulating property is provided at least in a portion exposed from the molten metal for its purpose and effect, but the heat insulating material layer and the void portion provided between the outer and inner side wall layers are Although it may be the entire area in the circumferential direction, some non-insulating material layer parts and void-free parts, such as providing support parts for reinforcement of the inner wall layer member or for certainty for the inner and outer wall layer construction Also, it is free as long as the effect of the present invention is not significantly impeded. (It suffices that the effect of preventing metal adhesion and deposition is not greatly impeded.) In addition, in the present invention, a portion having a multilayer structure such as a heat insulating material layer portion and a void portion is provided at least in an exposed portion from the molten metal. The purpose of the present invention is to suppress the heat radiation from the stalk itself, enhance the heat insulating effect, and ensure the effect of the present invention.

As described above, the structure having the inner side wall layer, the outer side wall layer, and the heat insulating material portion and the void portion between the layers allows the original performance to be sufficiently maintained, and the product has a long life and can be operated safely. It is possible to provide a low-pressure casting stalk capable of solving various problems such as improving the quality and yield of the product.

Next, examples will be shown.

[0011]

[Table 1]

The materials used in the examples are shown in Table 1 below.

[0013]

[Table 2]

The material A is shown in Table 1 as SiC, Si ₃ N ₄ and Si material. Mix proportions, mold by slip casting method, and perform reaction sintering in nitrogen gas atmosphere,
To produce. This material is used as both the outer wall layer material and the inner wall layer material in the examples of the present invention. B material compounded in ratios shown in Table 1 the _{SiC-Si 3 N 4 -Y 2} O 3 quality material as a raw material, adjusted, rubber pressing (CI
P), a high pressure of 3000 kg / cm ² is applied, and after forming, raw processing is performed and sintering is performed in a nitrogen atmosphere to produce. This material is used as the inner wall layer material in the examples of the present invention.

[0015]

[Example] When using a stalk having an inner diameter of φ60, an outer diameter of φ110, and a length of 1,000 m and an upper flange portion of 30 mm × 30 mm, the molten metal immersion portion is always 500 from the bottom of the stalk.
A working example is shown as a stalk for a low-pressure casting machine used in a state of being immersed in mm. The void is formed 20 mm below the top of the stalk and 80 mm below the stalk.

[0016]

[Table 3]

Next, an embodiment will be described. Results of use and comparison
Used by mounting on a low pressure casting machine. Casting material Aluminum with 99% Al content Casting pressure 0.6 kg / cm²± 0.03kg / c
m²  Molten metal temperature during casting 730 ° C ± 5 ° C

[0018]

[Table 4]

Adhesion amount (mm) B defective rate (%) (cast product defective rate)

As shown above, in the comparative example, the defective rate was as high as 10.8% in 320 hours of operation, and replacement was performed.
The defect rate after 1600 hours of operation has gradually increased to 4.2, but the present invention's embodiment shows that the stalk deposits in the holes are as low as 1.4 to 1.9 mm even after 1600 hours of operation. The defective rate was as low as 1.4% to 1.9%. 1 to 4, 1 is a void portion, 2 is a heat insulating material layer, 3 is an inner side wall layer, 4 is an outer side wall layer, 5 is an adhesive, and 6 is an Al molten metal surface.

[0021]

As shown in the above examples, the comparison product is 32
Adhesion was observed even after a long time of use, and the amount of adhered deposits reached 6.8 to 9.4 mm at 320 hours, and the use was stopped, and the comparative product continued to be used after 2.7 hours at 1600 hours.
There was 3.1 mm of adhesion, and the defective rate at this point was 4.2.
Example of the product of the present invention, which is higher than
, Has an adhesion amount of 0.3-0.
The defective rate was 9 mm, and the defective rate was 1.4% to 1.9%. The amount of metal adhered in the stalk hole was 23% to 24% compared to the comparative example, and the defective rate was 33% to 45%. There was no problem in operation, and the quality and product yield (reduction of defective rate) could be greatly improved, and the effect was great.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a conventional product comparative example ceramic stalk.

FIG. 2 is an explanatory view of a conventional product comparative example ceramic stalk.

FIG. 3 is an explanatory view of a ceramic stalk according to an embodiment of the present invention.

FIG. 4 is an explanatory diagram of a ceramic stalk according to an example of the present invention.

[Explanation of symbols]

 1 void part 2 heat insulating material layer 3 inner side wall layer 4 outer side wall layer 5 adhesive 6 Al molten metal surface

Claims (1)

[Claims] In the ceramic stalk used when pressurizing molten aluminum or aluminum alloy,
A ceramic stalk for low-pressure casting, which has a multi-layer structure including an inner wall (layer) and an outer wall (layer), and a heat insulating material layer made of a ceramic material and a void portion provided in an intermediate portion thereof.