JPH07112691B2 - Method for joining ceramic compacts - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a joining method for joining a plurality of ceramic compacts to each other to assemble them into a compact having a desired shape.

[Conventional technology]

The mud casting method, in which the sludge in which the ceramic particles are suspended is cast into a water-absorbing mold such as a gypsum mold, and the water is absorbed by the water-absorbing type, is the most commonly used method for molding ceramic compacts. It is being appreciated. It is also possible to obtain a highly densified ceramic molded body having a hollow cylindrical shape by causing the water absorption type to give a rotary motion in the casting of the sludge to cause the sludge to be inlaid under the action of a centrifugal force.

Immediately after being removed from the water-absorbing mold, the molded body (water content: about 18 to 20% by weight) is naturally dried, or an appropriate heating atmosphere (for example, 10
After being dried (water content of about 0.5% by weight) by heating at about 0 ° C.), rough machining is added or a sintering process is performed without adding to finish a fired product. The fired product is used for structural materials that require heat resistance and wear resistance, such as piping materials.

[Problems to be Solved by the Invention]

The hollow cylindrical ceramic molded body obtained by sludge casting is useful as a piping material, but the shape of the molded body is limited to a straight cylindrical body (straight pipe) having a uniform cross-sectional diameter. However, in the piping configuration, a flange for connecting the pipe materials is required, and it is often necessary to incorporate a bend pipe such as a 90 ° elbow or a deformed pipe such as a T-shaped or Y-shaped pipe.

In view of the above, the present invention provides a joining method for joining a plurality of ceramic compacts formed by mud casting to assemble them into a member shape necessary for the intended use.

[Means and Actions for Solving the Problems]

The present invention is formed by infiltration of mud in a water absorption mold,
In the method of butt-joining dried ceramic compacts after die-cutting, the portions to be joined to each other of the ceramic compacts are shaped into a shape that can be abutted, and the abutting surface is moistened in a humid atmosphere. The abutting surfaces are pressed against each other, and a state in which a pressing force is applied is maintained and dried.

Hereinafter, the present invention will be described in detail.

The present invention joins dried ceramic molded bodies (water content is generally 5% by weight or less) after being subjected to inking molding in a water absorption mold and removed from the mold. According to the present invention, first, a surface (butting surface) that allows mutual butting is shaped at a portion that becomes a joint portion of each ceramic molded body. FIG. 1 shows an example of assembling a flange tube as a ceramic molded body by joining an end surface (11) of a straight hollow cylindrical body (10) and a disk surface (21) of a disk body (20) having a donut shape. Since the end surface (11) and the board surface (12), which are the abutting surfaces in this case, are flat surfaces, the abutting surfaces are shaped by applying a knife to each surface and scraping the skin to obtain a smooth surface. All you have to do is add the allowance. FIG. 2 shows an example in which two straight hollow cylinders (30) and (40) are joined in a direction orthogonal to each other and assembled into a T-shaped tube. To the department
Opening (32) that matches the inside diameter of the other hollow cylinder (40)
In addition, on the end surface of the other hollow cylindrical body (40), an arcuate surface (41) corresponding to the outer peripheral surface of the one hollow cylindrical body (30) is formed by a cutter or the like, and the arcuate surface (41) and The butt surface is shaped by applying a knife to the outer surface (31) around the opening (32) facing it and smoothing it.
Figure 3 shows two straight hollow cylinders (50) and (60).
And a plurality of annular bodies (70, 70, 70, 70, 70, 70 having an inclined end face (71)
…) This is an example of forming a bent pipe such as a 90 ° elbow by combining straight hollow cylinders that may be cut obliquely. The shaping of the butt surface in this case is The end faces (51) (61) (71, 71, ...) of the above may be smoothed with a knife.

After shaping the abutting surface of each ceramic molded body, it is brought into contact with a humid atmosphere to wet the abutting surface by absorbing water. FIG. 4 shows an example of the moistening treatment. (1) is a chamber in which a humid atmosphere is formed. The ceramic molded body (10) to be moistened is a hollow cylindrical body used for, for example, assembling a flange pipe, and the hollow cylindrical body (10) is introduced into the chamber from a wall surface opening (2) of the chamber (1). After insertion, the end face (11), which is the butt face, is exposed to a humid atmosphere.

The moistening treatment is performed on each of the butted surfaces of each molded body,
It provides a viscous state that allows mutual fusion and binding, and is preferably moistened to a water content of about 15% by weight. However, if the water content is too high, deformation is likely to occur in the subsequent pressing and joining process of the butt surfaces, so it is preferable that the content does not exceed about 20% by weight. Also, if a water film or water droplets are formed on the surface of the molded body during the moistening treatment, the surface condition of the molded body may be deteriorated due to the dripping of the water. It is desirable to carry out under conditions that do not cause it.

The moistening condition may be appropriately set according to the material, water content, shape, etc. of the molded body, for example, a temperature of 30 to 40 ° C.,
It is preferably achieved by exposure to an atmosphere of 70-95% humidity for about 12-120 hours.

In the moistening treatment, the moistening is not limited to the abutting surface and the vicinity thereof, but over a rather wide area including the abutting surface, that is, in the moistening treatment shown in FIG. The insertion depth of the body (10) in the chamber (1) is increased to infiltrate over a wide region in the longitudinal direction from the end face (11) (for example, about twice the cross-sectional diameter or more),
When the wall thickness is smaller than the cross-sectional diameter like the disk body (20) (Fig. 1), it is preferable to wet the entire wall thickness. By doing so, the strain generated in the molded body in the subsequent drying process of holding the butted surfaces in a pressed state is effectively dispersed and reduced.

After subjecting each ceramic molded body to the above-mentioned moistening treatment,
Immediately, the abutting surfaces are abutted against each other, and a state in which an appropriate pressing force is applied is maintained, and the molded body is dried. The pressing force applied to the abutting surface may be, for example, about 0.3 to ² kg / cm ² . When the ceramic molded body to be joined is a hollow cylindrical body (10) and a disc body (20) that serves as a flange as shown in FIG. 1, the disc body (20) is placed on a horizontal base and the disc surface (21 ), The hollow cylindrical body (10) is placed upright, and the dead weight of the hollow cylindrical body (10) is used as a pressing force of the abutting surface to stand for a predetermined time to dry it. In the case of assembling the T-shaped tube shown in FIG. 2, one hollow cylindrical body (30) is held horizontally, and the other hollow cylindrical body (40) is placed upright on the hollow cylindrical body (30). The weight of the lever can act as a pressing force of the abutting surfaces. When the pressing force is insufficient due to its own weight, a load for compensating for the insufficient amount may be applied from above. Further, in the case of assembling the bend pipe of FIG. 3, for example, an appropriate outer frame member for holding the shape of the bend pipe is used and a pressing force is applied to the abutting surface by binding with a rubber band or the like. Good.

Drying while pressing the butt surface may be carried out by natural drying in the same manner as that of a normal ceramic molded body.
Drying is achieved by leaving it for about 0 hours. As a result, it is possible to obtain a molded product that is integrated by completely fusion-bonding the butted surfaces of the ceramic molded bodies. The process including the sintering treatment after drying may be performed in the same manner as that of a normal ceramic molded body.

The material of the ceramic molded body to which the present invention is applied is not limited, but for example, aluminum titanate (Al ₂ TiO ₅ ) powder 100
Parts by weight, kaolin powder 5 to 15 parts by weight, alumina powder 5 to 10
Participating in molding to cast mud containing parts by weight and an appropriate amount (eg 0.3 to 0.7 parts by weight) of the required amount of mud adjusting agent (eg, peptizing agents such as sodium pyrophosphate, sodium aluminate, ethylamine, piperidine) It is suitably used for joining the ceramic molded body obtained by the above (which is useful as a radiant tube of a steel heating furnace, for example).

〔Example〕

[I] Molding of test ceramic compact: 85 parts by weight of aluminum titanate powder, 10 parts by weight of kaolin powder, 5 parts by weight of alumina powder, 0.5 part by weight of peptizer (sodium pyrophosphate), and water (solid content) 25 parts by weight of 100 parts by weight of mud (average particle size of powder: 1μ)
m) was prepared and subjected to centrifugal casting (the centrifugal force on the peripheral surface of the water-absorbing mold was 7G in terms of gravity multiple) to form the hollow cylindrical body (10) and the disk body (20) to be the flange shown in FIG. Molded.
Hollow cylinder (10) outer diameter: 70mm, inner diameter: 50mm, trunk length: 500mm.
Disc body (20) outer diameter: 110 mm, inner diameter: 50 mm, wall thickness: 10 mm.

[II] Butt joining of ceramic molded bodies: After being removed from the water-absorbing mold, it becomes the butt surface of the hollow cylindrical body (10) and the disk body (20) (both have a water content of about 0.4% by weight) that have been naturally dried. The end surface (11) and the board surface (21) were thinly shaved and smoothed, and the hollow cylindrical body (10) was fitted with a disk lid (3) in its hollow hole as shown in FIG. ), And the disc body (20) was entirely moistened by inserting it into the chamber (1). However, the atmosphere in the chamber (1) is adjusted to a temperature of 30 ± 2 ° C and a humidity of 85 ± 5%, and the processing time is 100
It was time.

After the above-mentioned hollow cylindrical body (10) and disk body (20) are moistened, they are immediately stacked on a horizontal table, and the pressing force by the dead weight of the hollow cylindrical body (10) is applied to the abutting surface thereof.
It was left in the air for 0 hours to dry. The water content near the butt joint at the end of drying is about 0.5% by weight.

[III] Firing of molded body and measurement of joint strength After the joint molded body was sintered at 1150 ° C. for 10 hours in a sintering furnace, a rectangular parallelepiped was formed from a region including a joint part of the sintered product. Shaped test piece a (length in the thickness direction: 5 mm, length in the circumferential direction: 5 mm, length in the axial direction: 40 mm), and test piece b having the same shape from the region of the hollow cylindrical body (10) Was cut out, and the strength of each was measured by the three-point bending method, and the following results were obtained.

Test piece a (joint) …… 500kgf / cm ² Test piece b (non-joint) …… 700kgf / cm ² As mentioned above, the butt joint has sufficient strength required as a structural material such as piping material. have.

〔The invention's effect〕

According to the method of the present invention, a plurality of ceramic compacts can be assembled in various forms, and the joints have sufficient strength required for various structural materials. Therefore,
The degree of freedom in designing the shape of ceramic products is increased, and a great effect is obtained in expanding and diversifying its applications.

[Brief description of drawings]

1 to 3 are views showing an example of joining a ceramic molded body according to the present invention (FIG. 1 is a perspective view, FIG. 2 is a front view, and FIG. 3 is a side view), and FIG. 4 is a ceramic molded body. It is sectional drawing which shows the example of the moistening process point. 10,20,30,40,50,60: Ceramic molded body, 11,21,31,41,51,
61,71: Butt faces.

Claims (2)

[Claims] 1. In a method of butt-joining dried ceramic compacts formed by infiltration of mud in a water-absorbing mold and then removed from the mold, portions of the respective ceramic compacts to be joined can be butted. A method for bonding a ceramic molded body, which comprises shaping into a shape, moistening the abutting faces in a humid atmosphere, pressing the abutting faces together, and maintaining the state in which a pressing force is applied and drying. 2. The abutting surface of each ceramic molded body has a water content.
The method for joining ceramic molded bodies according to claim 1, wherein the method is wetted to 15% by weight or more.