JPS6045027B2 - Centrifugal casting method for irregularly shaped pipes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the provision of a new casting means for obtaining an irregularly shaped tube such as a T-shaped tube having a branch tube on a part of the outer peripheral surface of a tube body by centrifugal casting means.

Needless to say, various types of irregularly shaped pipes having branch pipes on a part of the outer circumferential surface of the pipe body are known, but it is difficult to cast such irregularly shaped pipes by centrifugal casting, and conventionally, centrifugal casting has been used exclusively. It was cast using the placing method.

However, when casting a different-shaped pipe using the pouring method, it is necessary to mold and arrange the core, which takes time and requires a large feeder, resulting in a low material yield. The quality of the tube is also inferior to that produced by centrifugal casting. In this way, the placement method has problems in terms of overall productivity and economy, and is not suitable for mass production of irregularly shaped tubes. The present invention makes it possible to easily obtain such a special-shaped pipe having a branch pipe on a part of the outer peripheral surface of the pipe body by a centrifugal casting method. When centrifugally casting a different-shaped pipe with branch pipes on the surface, the branch pipe forming position of the centrifugal casting mold made of foundry sand protrudes inward from the inner surface of the mold by the thickness of the pipe body casting wall and can be welded to the pipe body casting molten metal. This method consists in embedding a branch pipe forming member, and casting the mold in the branch pipe forming member into a centrifugal casting mold that projects inward by an amount larger than the casting wall thickness of the pipe main body.

The method of the present invention will be described in detail with reference to the embodiments shown below. Fig. 1 is a front cross-sectional view of a centrifugal casting mold. It is placed on top and is rotatably supported. A band 3 is fixed to the inner surface of one open end of the metal rod 1, and is detachably attached to the metal rod 1 via a fixing member 4 such as a pin.

3' indicates an end ring fixed to the inner surface of the other open end of the metal bar 1.

5 is a centrifugal casting mold using J foundry sand, which is located between the band 3 and the end ring 3' and is filled with a lining on the inner surface of the metal rod 1. The centrifugal casting mold using fluidized sand is the most popular method for making this. A suitable but conventional method is also possible, and the tube body (shown in dotted lines) of the profiled tube is cast on the inner surface of this mold 5.

Incidentally, it goes without saying that the inner surface of the mold 5 is coated with the mold 7.
be. Accordingly, in the present invention, when the desired molten metal for casting the pipe main body is poured into the desired branch pipe forming position of the mold 5 from the pouring trough from the zero point, etc. A branch pipe forming member 6 of a desired shape made of the same material as the pipe main body or a different material that can be integrally welded with the molten metal is buried in advance. This branch pipe forming member 6 was previously made by centrifugal casting, and the casting wall thickness D of the pipe body was set so that it could come into contact with the molten metal and obtain the best possible integral welding method with the pipe body. The part A of the mold 5 (corresponding to the core of the branch pipe), which is located inside the branch pipe forming member 6 and which is in a state of protruding inward, is a part A of the mold 5 (corresponding to the core of the branch pipe), which is a part of the mold 5 that is located inside the branch pipe forming member 6. It is made to protrude inward by an amount larger than the casting wall thickness D of the tube body so that the tubes are connected. Generally, the wall thickness of the branch pipe is thinner than that of the main pipe (because the diameter is smaller), and welding is easier.
To explain in more detail about the branch pipe forming member 6, if the protruding end B is oxidized or contaminated with oil or fat, the weldability between the branch pipe forming member 6 and the pipe body will deteriorate, which is undesirable. , Therefore, the protruding end B of this branch pipe forming member 6 has the following:
It is preferable to apply anti-corrosion treatment such as Zn plating to prevent oxidation, and furthermore, to promote the weldability of both, Ni-P
It is also more effective to apply plating or the like. In addition, in the case of Fig. 1, the protruding end B of the branch pipe forming member 6 is simply made upright with respect to the pipe body to be cast, but in order to obtain even stronger bonding to both. In some cases, the second
As shown in Figures A, b, c, and d, the protruding end B of the branch pipe forming member 6 can be formed so that the joint area between the two is large or the two are interlocked. When an irregularly shaped pipe with branch pipes is centrifugally cast using such a mold, the buried branch 5 pipe forming member 6 causes the center of gravity of the metal frame 1 as a whole to become eccentric during rotation, causing normal problems such as wobbling. In order to prevent this, it is preferable to appropriately attach a balance weight 7 to the outer peripheral surface of the metal frame 1 located on the opposite side of the branch pipe forming member 6. As mentioned above, if the branch pipe forming member 6 is buried in advance and the centrifugal casting mold is used, and the molten metal is poured from the pouring trough from 1 trough as usual, the pipe body can be cast in the same manner as in the case of normal centrifugal casting of the pipe body. At this time, the branch pipe forming member 6 and the pipe main body are integrally welded, and a deformed pipe having the desired branch pipe is cast.

Then, after the required time has elapsed after casting, it is sufficient to remove the cast irregular-shaped pipe from the metal frame 1, and it is possible to easily obtain a centrifugally cast irregular-shaped pipe in which the branch pipes are integrally welded to the pipe body. . In manufacturing the centrifugal casting mold used in the present invention, it is only necessary to embed the branch pipe forming member 6 in the desired position, and compared to the case of centrifugally casting a normal pipe body, the It also has the advantage that the work process is not so complicated and the conventional centrifugal casting metal frame can be used as is. In addition, in the case of the pouring method, the molding arrangement of the core was indispensable, but according to the centrifugal casting of the present invention, the mold 5 can be efficiently molded without the need for a core at all, and the mold 5 can be molded efficiently. In the end,
Of course, it is also economical because it does not require a riser and the cutting allowance can be reduced. Due to the characteristics of centrifugal casting, the cast irregular-shaped pipes are guaranteed to have higher quality than those made by the pouring method, and if attention is paid to the welding and bonding properties of the branch pipe forming member 6 as described above, it is possible to prevent joint problems in the branch pipes. It doesn't cause any problems. As described above, according to the present invention, various types of irregularly shaped pipes such as T-shaped pipes having branch pipes on a part of the outer circumferential surface of the pipe body can be manufactured efficiently, economically, and by centrifugal casting.
Moreover, it has become possible to cast with high quality, and when mass producing irregularly shaped pipes, if the method of the present invention is used instead of the conventional pouring method, it will bring about an extremely large industrial effect.

[Brief explanation of the drawing]

FIG. 1 is a front sectional view of a centrifugal casting mold used in an embodiment of the present invention, and FIGS. 2A, b, c, and d are enlarged explanatory views showing the shape of the protruding end of the branch pipe forming member. 1...Mold, 5...Mold, 6...
...Branch pipe forming member.

Claims (1)

[Claims] 1. When centrifugally casting a deformed pipe having branch pipes on the outer circumferential surface of the pipe body, the pipe body is placed on the inner surface of the mold at the position where the branch pipes are formed in the centrifugal casting mold using foundry sand, protruding inward by the thickness of the pipe body casting wall. It is characterized by embedding a branch pipe forming member that can be welded to the casting molten metal, and casting the mold in the branch pipe forming member into a centrifugal casting mold that projects inward by an amount larger than the casting wall thickness of the pipe body. A method for centrifugal casting of irregularly shaped tubes.