JP2003088949A - Method for producing casting having slender hole as cast - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for simply and economically producing a casting having a slender hole as cast having extremely little deformation, such as bending, strain. SOLUTION: This method for producing the casting having the slender hole as cast, is the one, with which molten metal for casting is poured into a mold disposing a non-metallic inorganic fine tube or bar-like core, and cooled and successively, after releasing a flask, the above non-metallic inorganic fine tube or the bar-like core is removed. The non-metallic inorganic fine tube or the bar-like core has desirably 300-1600 deg.C softening point. The above non-metallic inorganic fine tube or the bar-like core is desirably a quartz fine tube core.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a casting having an elongated casting hole with very little deformation.

[0002]

2. Description of the Related Art For example, a hydraulic apparatus made of casting is provided with a thin pipe section or groove section for circulating and supplying hydraulic oil to a necessary portion in the apparatus. Conventionally, the formation of thin pipes and grooves on such cast devices and parts has been performed by post-processing using a long drill or the like after casting. Further, in the case of forming a slightly thick pipe portion or groove portion in a casting, a steel pipe is disposed as a core in a mold in advance and the casting is performed.

[0003]

However, the method of making a long hole in a casting using a long drill or the like is
There are problems that the long drill breaks during processing and that it takes a long time for drilling. Further, the method of casting a casting having a tube portion or a groove portion using a steel tube core has a problem that when forming a thin tube portion or a groove portion, the bending and distortion become too large and not practical.

An object of the present invention is to provide a method for easily and economically producing a casting having an elongated casting hole with extremely small deformation such as bending and distortion.

[0005]

In order to achieve the above-mentioned object, the present invention is a method of pouring a molten metal for casting into a mold in which a non-metal inorganic thin tube or a rod-shaped core is arranged, cooling, and then unmelting. The method for producing a casting having an elongated cast hole, characterized in that the nonmetallic inorganic thin tube or the rod-shaped core is removed after being framed.

According to the present invention, the non-metal inorganic thin tube or rod-shaped core has a softening point of 300 to 1600 ° C.
It is a method of manufacturing a casting having the elongated casting hole.

The present invention is the method for producing a casting having the above-mentioned elongated casting hole, wherein the non-metal inorganic thin tube or rod-shaped core is a quartz thin tube core.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
The core in the present invention is a graphite rod (particularly an electrode graphite rod), a rod obtained by solidifying sand with a resin such as phenol resin, a quartz pipe, various glass pipes, a non-metal inorganic thin pipe or a thin rod such as a graphite-coated metal rod. . Of these, there is little deformation after casting,
Quartz thin tubes are most preferable because they are easily removed. Also,
This non-metal inorganic thin tube or thin rod has a softening point of 300 to 16
00 ° C, further 600 to 1600 ° C, especially 1400 to 15
It is preferably at 50 ° C. Further, the non-metal inorganic thin tube or thin rod has an outer diameter (diameter) of 1 to 20 mm, further 3 to 10 mm, and a length of 500 mm or less, further 10
A value of 0 to 300 mm is suitable for use in the method of the present invention. If the outer diameter is less than 1 mm, the deformation during casting becomes large, and if the outer diameter exceeds 20 mm, it is more economical to use a post-processing method using a long drill or a casting method using a steel pipe core. Manufacturing (processing)
Is also easy.

As the casting metal in the present invention, various cast irons, aluminum, zinc, alloys thereof and the like can be mentioned, and various cast irons are particularly suitable for the method of the present invention.

In order to remove non-metal inorganic thin tubes or rod-shaped cores from a cast product, the core is crushed and pierced by an ordinary drill used for drilling concrete, and an elongated cast hole is formed in the cast product. It can be easily formed.

[0011]

EXAMPLES The present invention will be described in more detail below with reference to examples. FIG. 1 is a plan view of an upper die and a lower die used for manufacturing a casting having an elongated casting hole according to the present invention. 2 is shown in FIG.
FIG. 3 is a perspective view (including an imaginary part) of a mold in which the upper mold and the lower mold are set. FIG. 3 is a side sectional view taken along line AA of the mold in which the upper mold and the lower mold of FIG. 1 are set. FIG. 4 is a cross-sectional perspective view (including part of an imaginary part) in a quartz tube disposing portion of a cast product manufactured by the method of the present invention. FIG. 5 is a cross-sectional perspective view showing a state where the quartz tube is removed from the casting shown in FIG. FIG. 6 is a cross-sectional view for explaining the degree of bending (distortion) of an elongated casting hole of a casting.

The mold (sand mold) used in the embodiment of the present invention shown in FIGS. 1 to 3 comprises an upper mold 3 and a lower mold 4. Lower mold 4
The casting hollow part 5b has a diameter of 5 mm and a length of 250 mm.
The quartz tube 1 is disposed at a portion forming the elongated casting hole 1a of the casting. Both ends (skirting board) 9 of this quartz tube 1
In order to fix the quartz tube 1 in the mold (hollow portion 5 for casting) by burying it in the side surface of the mold, a rod of the same thickness obtained by solidifying sand with phenol resin is inserted into the quartz tube 1 and bonded. This is to prevent fragments of the quartz tube 1 from mixing into the unmolded sand (which is the material of the mold) during the unraveling (unmolding). The upper surfaces of the upper mold 3 and the lower mold 4 were joined together as shown in FIG. 2 to assemble a mold and used for casting. Molten metal (molten cast iron: FC250, FCD450, specific gravity of 7.380 to 1420 ° C. from the pouring port 7 of the mold).
2) was poured. When the molten metal filled the casting hollow portion 5 in which the quartz tube 1 was arranged, from the pouring port 7 through the pouring portion 6 and the molten metal passage 8, the pouring was finished. After cooling, the mold was unframed (separated from the mold) and the pouring port and the pouring portion were cut to obtain a casting 2 in which the quartz tube 1 was cast. This casting 2
Quartz tube 1 with an outer diameter of 4 mm (for drilling concrete)
Apply the blade of a drill, crush it, and then pierce it to make an elongated casting hole 1
a was formed. It was easy to crush and remove the quartz tube 1.
In addition, the casting 2 is cut along the elongated cast hole 1a to form the hole 1
When the degree of strain of a was measured, the strain distance (perpendicular length) h from the line connecting both ends of the hole to the furthest part of the elongated casting hole 1a was 0.2 mm / hole length 250 mm
Was (see FIG. 6).

For comparison, using the same mold as described above, instead of the quartz tube 1, a steel tube having a diameter of 5 mm and a length of 250 mm is arranged in the casting hollow portion 5b, and the steel is manufactured in the same manner as the above method. A casting 2 in which a pipe was cast was produced. When the casting 2 was cut along the steel pipe installation portion and the degree of distortion was measured, the distortion distance h from the line connecting both ends of the hole to the farthest part of the elongated casting hole 1a was 5 mm.
/ The length of the steel tube was 250 mm.

[0014]

As described above, according to the present invention, it is possible for the first time to provide a method for easily and economically producing a casting having an elongated cast hole with extremely small deformation such as bending and distortion.

[Brief description of drawings]

FIG. 1 is a plan view of an upper die and a lower die used for manufacturing a casting having an elongated casting hole according to the present invention.

FIG. 2 is a perspective view (including an imaginary portion) of a mold in which the upper mold and the lower mold of FIG. 1 are set.

FIG. 3 is an AA of a mold in which the upper mold and the lower mold of FIG. 1 are set.
It is a side sectional view in a line.

FIG. 4 is a cross-sectional perspective view of a quartz tube installation portion of a cast product manufactured by the method of the present invention.

5 is a cross-sectional perspective view showing a state in which a quartz tube is removed from the casting shown in FIG.

FIG. 6 is a cross-sectional view for explaining a degree of bending (distortion) of an elongated casting hole of a casting.

[Explanation of symbols]

1 quartz tube 1a Slender cast hole 2 castings 3 Upper mold 4 Lower mold 5 Hollow part for casting 6 Pouring part 7 pouring spout 8 molten metal passage

Claims (3)

[Claims] 1. A non-metal inorganic thin tube or rod-shaped core is removed by pouring a molten metal for casting into a mold in which a non-metal inorganic thin tube or rod-shaped core is arranged, cooling and then opening the frame. And a method for producing a casting having an elongated cast hole. 2. The non-metal inorganic thin tube or rod-shaped core has a softening point of 300 to 1600 ° C.
A method of manufacturing a casting having an elongated casting hole according to [4]. 3. The method for producing a casting having an elongated casting hole according to claim 1, wherein the non-metallic inorganic thin tube or rod-shaped core is a quartz thin tube core.