JPH0735645Y2 - Stoke for casting - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention mainly relates to improvement of stalk used in low pressure casting.

[Outline of the Invention] The present invention encloses both inner and outer sides including a lower end of a metal tubular body with a heat insulating wall made of a refractory material, and forms a coating film having wettability on the surface thereof to provide heat insulation and heat insulation. sex,
This is a casting stalk having excellent durability and wettability.

[Prior Art] Conventionally, tubular cast iron stalks are often used as low-pressure casting stalks. Since this cast iron stalk has sufficient mechanical strength and is non-breathable, it has excellent resistance to external impact when it is attached to the mold and facilitates the press-fitting of molten metal into the mold. However, on the other hand, it is easily eroded by the molten metal, the inner diameter of the cylinder becomes small due to the adhesion of the molten metal, the passage of the molten metal deteriorates, and the temperature of the molten metal passing through the stalk decreases due to heat conduction. There are drawbacks such as.

Therefore, in order to eliminate the drawbacks of the cast iron stalk, an insulating layer made of an inorganic material is formed inside and outside the metal stalk, respectively, and various structures are improved to have wettability against molten metal and thermal insulation against heat conduction. Type stalk has been proposed.

[Problems to be solved by the invention] However, even the improved stalks proposed so far are not satisfactory in all of the desired wet resistance, heat insulation, and durability, and points to be improved and improved. There are many left.

[Object of the Invention] An object of the present invention is to provide a low-pressure casting stalk having significantly improved wettability, heat retention, heat insulation, and durability as compared with the conventional improved stalk.

[Means for Solving the Problems] In the casting stalk of the present invention, a thin-walled metal cylinder is used as a core of the stalk, a ceramic fiber blanket is attached to the outside of the cylinder, and the lower end of the cylinder is attached. A thick heat insulating wall of a refractory material composition consisting of wollastonite / alumina cement / fiber material is formed between the inner side including the ceramic fiber blanket and the outer side provided with the ceramic fiber blanket, and ceramic paper is attached to the surface of the heat insulating wall outside the cylinder. The gist is a structure in which a coating film of a boron nitride solution is formed on the entire surface including the heat insulating walls on the inner and lower ends of the cylinder and the ceramic paper on the outside of the cylinder.

[Operation] In the stalk having the above-described configuration, since the tubular body is surrounded by the thick heat insulating walls made of the refractory material formed on both the inner and outer sides including the lower end thereof, the high heat retaining property and the excellent heat insulating property are achieved. In addition, it has a remarkable effect of preventing the temperature drop of the molten metal passing through the stalk, and also has a remarkable effect of preventing the adhesion of the molten metal in combination with the boron nitride coating film on the surface. Further, since ceramic paper is provided on the outer side of the cylindrical body in addition to the heat insulating wall, the effect of preventing heat dissipation to the outside is further enhanced.

[Embodiment] FIGS. 1 and 2 show an embodiment of the present invention.

In the figure, reference numeral 1 denotes a metal cylindrical body which serves as a core of the stalk, and a thin iron pipe is used. Reference numeral 2 is a flange which is welded to the tubular mouth of the tubular body.

On the outer side of the cylindrical body 1, a blanket 3 made of ceramic fibers together with an expanded metal or a wire net 4,
It is attached via a welding stopper 5, and a similar blanket 6 is also provided at the lower end of the tubular body. Furthermore, wallastonite / alumina cement / alumina cement / A thick insulating wall 7 of a refractory composition of polypropylene fiber / alkali resistant glassy fiber is integrally formed.

The refractory composition is integrated into the cylinder by, for example, setting the cylinder 1 with a blanket / mesh attached in a mold, then pouring the composition for curing, and then demolding, drying and firing. It is obtained by doing.

The composition of the wollastonite / alumina cement / polypropylene fiber / alkali resistant glassy fiber refractory composition used for the heat insulating wall 7 is 60 to 40:40 to 60: 0.1 to 0.3: 0.
Those prepared in the range of 0.5 to 0.5 (weight ratio) are preferable.

Of the heat insulating wall 7 of the cylindrical body 1, the surface of the heat insulating wall 7 outside the cylindrical body 1 has a ceramic paper 8 of about 2.5 mm thickness.
Is adhered with an inorganic adhesive, and a boron nitride solution coating film 9 is formed on the surface of the ceramic paper 8 and the entire surface of the heat insulating wall 7 formed on the inner and lower ends of the cylindrical body 1.

According to the Stokes structure shown in the above embodiment, the following effects can be obtained.

[1] Since the heat insulating wall 7 that surrounds both the inner and outer sides including the lower end of the tubular body 1 is made of a refractory material composition composed of wollastonite / alumina cement / fibrous material, it has high heat retention and excellent heat retention. It has a heat insulating property, and has a remarkable effect in preventing the temperature of the molten metal from passing through the stalk, and also has a remarkable effect in preventing adhesion of the molten metal together with the coating film 9 of the boron nitride solution on the surface.

[2] When the heat insulating wall is formed only of alumina cement which has been frequently used as a heat resistant lining material, cracks due to temperature rise and shrinkage easily occur during firing or contact with molten metal, but as described above Since night and fiber materials are added and compounded, there is no risk of damage due to temperature. Further, the addition of wollastonite further improves the heat resistance and heat insulation.

[3] The heat insulating wall 7 is a tubular member that replaces the conventional Stokes cast iron pipe mainly composed of a cast iron pipe, and the metal cylinder corresponding to the core bar prevents air leakage of the heat insulating wall made of the composition. Playing a role.

[4] On the other hand, on the outside of the cylindrical body, since the blanket 3 of ceramic fibers and the ceramic paper 9 are provided in addition to the heat insulating layer 3, it is further reinforced by the effect of preventing heat dissipation to the outside. .

[Effects of the Invention] As described above, according to the present invention, the wettability that prevents the adhesion of the molten metal, the heat insulation property that prevents the temperature of the molten metal from decreasing, and the durability are significantly improved compared to the conventional stalk. You can get the stoke.

[Brief description of drawings]

FIG. 1 is a side view of a stalk showing an embodiment of the present invention,
FIG. 2 is an enlarged vertical sectional view of the main part. 1 ... Metal cylinder, 2 ... Flange, 3 ... Ceramic fiber blanket, 4 ... Wire mesh, 5 ... Welding stopper,
6 ... Blanket, 7 ... Insulation wall, 8 ... Ceramic paper, 9 ... Boron nitride coating film.

Claims (1)

[Scope of utility model registration request] 1. A thin-walled cylindrical body made of metal is used as a stalk core, a ceramic fiber blanket is attached to the outer side of the cylindrical body, and an inner side including the lower end of the cylindrical body and an outer side provided with the ceramic fiber blanket. A thick heat insulating wall made of a refractory composition composed of wollastonite / alumina cement / fibrous material is formed, and ceramic paper is attached to the surface of the heat insulating wall on the outer side of the cylinder. A stalk for casting, characterized in that a coating film of a boron nitride solution is formed on the entire surface including the ceramic paper outside the body.