JPH0323052A - Method for casting casting product having hole part - Google Patents

Abstract

PURPOSE:To cast a casting product having hole part without any apprehension of gas leakage by fitting a metal pipe so that the head part thereof is out from an insert stood into cavity, allowing molten metal to flow down from the head part and welding the head part and molten metal to insert the head part as internal chill. CONSTITUTION:The metal pipe 3 is fitted so that the head part 5 thereof is out from the insert 2 stood at bottom of a mold toward the casting cavity 1. Successively, from upper part of the insert position, the molten metal is made to flow down to the tip part 4 of insert 2 and made to overflow from a recessed part 6 formed with the head part 5 of metal pipe 3 and the top part 4 of insert 2 to the arrow mark direction to melt the head part 5 of metal pipe 3. Under condition of welding the metal pipe 3 and molten metal, at the time of stopping supply of the molten metal and cooling, the metal pipe 3 is made to standing shape on casting plate and the outer face of barrel part of the metal pipe 3 is inserted as internal chill condition with the molten metal. This casting product is detached from the mold and the insert 2 is removed and unnecessary part is mechanically removed so as to open the hole part to obtain the casting product without any apprehension of gas leakage.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for casting a casting having holes of accurate dimensions and without fear of air leakage.

(Prior Art) An example of a casting having a hole is an intake for a manifold of an internal combustion engine as shown in FIGS. 3 and 4.

The hole in this casting is cast using a shell core or the like. The smoothness of the casting surface of the inner surface of the hole in the obtained casting is not sufficient.

Therefore, a wrought material vibrator is inserted into this boat part, but in this structure, a flange is attached to the pipe or the pipe is welded to the cast material. Such a manufacturing method requires a lot of man-hours and is prone to defects.

The method of casting pipes in castings was developed in Japanese Patent Application Laid-open No. 62-21.
As shown in Japanese Patent Application Laid-open No. 453 and Japanese Patent Application Laid-Open No. 62-21454, there are conventional methods, but they cannot be applied to the above-mentioned articles.

(Problem to be Solved by the Invention) In view of the above-mentioned circumstances, it is possible to easily make the hole of accurate dimensions and to prevent leakage when the hole of a casting having a hole is machined. There is a need for a casting method that allows castings to be made without fear of heat.

(Means for Solving the Problems) The present invention was invented in order to solve the above-mentioned problems, and the present invention is a method in which a metal tube is placed in an insert set upright in a casting cavity, and the metal tube is guided from the top of the insert. The head of the metal tube is melted while flowing the molten metal from above the insert position to the top of the insert to fuse the metal tube and the molten metal.The supply of molten metal is stopped and the metal tube is cast by cooling. This is a casting method for castings with holes that are characterized by holes.

It is preferable that the metal tube extends from the top of the insert by about 1 mm to 2+++ m from the flat surface of the top of the insert.

Good results can be obtained by making sure that the molten metal overflows from the area where the metal tube extends from the top of the insert in a radial and even manner. In order to cause the molten metal to flow down to the top of the insert, a tiltable molten metal box is provided above the casting cavity, and the molten metal accumulated in the molten metal box is allowed to flow down while controlling the tilting speed.

The metal tube is preferably a wrought material, and more preferably one with similar components. In order to melt and weld the tip of a metal tube with molten metal, the amount of molten metal that fills the casting cavity is insufficient, so the molten metal must overflow from the casting cavity. For this purpose, it is advisable to tilt the mold by 1° to 5°. The overflowing molten metal is returned to the molten metal holding furnace to maintain its temperature and to be used for re-pouring.

(Operations and Examples) As shown in Fig. 1, the metal tube (3) is fitted with its head protruding from the insert (2), which is erected at the bottom of the mold toward the casting cavity (l). , flows down from above the insert position to the top (4) of the insert (2) as shown by the arrow in the figure, and is formed by the head (5) of the metal tube and the top (4) of the insert Due to the molten metal overflowing from the recess (6) as shown by the arrow in the figure,
The head (5) of the metal tube (3) melts.

Then, when it is cooled as it is, it is fused and the metal pipe (3) is installed in the casting plate.

Since the outer surface of the body of the metal tube end (7) is also in contact with the molten metal, the melt and molten metal react well with the outer surface of the body of the metal tube (3), resulting in casting in the same condition as conventional casting. will be included.

When observing the boundary between the metal tube and the casting using a metallurgical microscope, the second
It is welded as shown in the figure.

The casting from which the mold has been removed and the bulge (2) has been removed becomes a product casting by removing unnecessary parts where the molten metal has solidified by machining so that the holes are open.

(Effects of the Invention) As explained in detail above, the method for casting a casting having a hole according to the present invention involves placing a metal pipe into an insert set upright in a casting cavity and positioning the metal pipe from the top of the insert. Then, while flowing the molten metal from above the insert position to the top of the insert, the head of the metal tube is melted to fuse the metal tube and the molten metal, and the supply of molten metal is stopped and cooled to cast the metal tube. Because it is constructed so that it is wrapped around, the head of the metal tube and the molten metal are completely welded, and the other parts are also joined by casting, and the inner surface of the hole is made of wrought material, etc. Since it is finished by machining, the inner surface of the hole is smooth and there is no risk of air leakage.

Because of these effects, the present invention has many important contributions to the development of industry.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the state during pouring of molten metal by the casting method of the present invention, Figure 2 is a metallurgical microscope observation of the welded part of the metal tube and casting, and Figures 3 and 4 are of the conventional product. It is a schematic diagram. 1. ．． ．． ．． ．． Casting cavity; 2. ．． ．． nest; 3. ．． ．． ．． ．． Metal tube; 4. ．． ．． ．． ．． Top of nest; 5. ．． ．． ．． Head of metal tube; 6... recess; 7. ．． ．． ．． Metal tube end.

Claims (1)

[Claims] A metal tube is fitted into a core set upright in a casting cavity with the head pointing from the top of the insert, and the head of the metal tube is melted while flowing molten metal from above the insert position to the top of the insert. A method for casting a casting having a hole, characterized in that the metal tube and the molten metal are welded together, the supply of the molten metal is stopped, the metal tube is cooled, and the metal tube is cast.