JPH07124692A - Method for casting jacket structural cast product - Google Patents

Abstract

PURPOSE:To provide a casting method, by which a cast product having a jacket structure can be cast at a stroke in only the casting process without cutting and boring works, under coping with the present situation, in which the casting is mainly executed to the outline formation and the detail is obliged to fall back upon the cutting and the boring works after casting. CONSTITUTION:Split molds 1, 2 divided so as to be possible to form with a lost foam material, are formed and joined to constitute a lost foam pattern T having a jacket structure. Sand grains G having high thermal conductivity are filled into this hollow part and this outside is surrounded with sand grains S having the lower thermal conductivity than the sand grains filled into the hollow part, and molten cast metal is poured into the lost foam pattern part to execute the casting. By this method, the casting of the jacket structural cast product can be executed at a stroke, related to a product, such as a double structural product executing the boring work from a solid cast product, a product enabling the lightening. Large effects on the rationalization of the working process, the lightening of the product and the applied field of the cast product are obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for casting a copper alloy casting, an iron casting, an aluminum alloy casting or the like having a double structure having a hollow portion, that is, a casting having a jacket structure.

[0002]

2. Description of the Related Art Conventionally, casting methods for castings are performed by synthesizing a fixed division mold by the operation of a split die supporting portion to form a cavity in the shape of the casting, and pouring molten metal into the cavity for casting. A method of separating the split molds and taking out the product, embedding a wooden mold or core in the shape of a cast model in sand mixed with resin etc. to solidify the sand, set the core in the hollow part where the wooden mold was removed, and melt The method of pouring and casting has been carried out.

After that, a cast model is formed from the disappearing material, the molten metal is poured into the model portion without extracting the model, the model disappears due to the high heat of the molten metal, and the model and the molten metal are replaced, and the same as the model. Methods for casting shaped castings have become commonplace.

[0004]

However, since the conventional mold is centered on the formation of cavities, it is difficult to cast the mold including the internal structure, and the mold is limited to the minimum one using a core or the like.

The conventional vanishing mold enables fairly precise casting in order to make up for this point, but it is centered on the external casting, and the details have to rely on cutting and punching after casting. is the current situation.

In particular, when the finished product has a jacket structure, if the jacket structure is desirable as a weight problem, it is cast into a workable shape, and the products cut after the casting are joined by welding. , I had to refinish.

The problem to be solved by the present invention is to cope with the above situation and to provide a casting method capable of casting a jacket structure casting at a casting stage without cutting or punching. is there.

[0008]

[Means for Solving the Problems] That is, the present invention addresses the above problems and divides a processed portion which has been conventionally cut and cut after casting into easy-to-process units and re-forms as a mold. In this case, in the step of forming the vanishing mold that can be freely processed, the unit-split mold is divided into units that can be molded as the vanishing mold.

By joining the split molds with an adhesive and applying a coating mold, a complete vanishing mold is constructed as a finished product having a jacket structure, and the hollow part is filled with sand grains having high thermal conductivity, and the outside is hollow. The object was achieved by wrapping with sand particles having a lower thermal conductivity than the sand particles with which the part was filled, and pouring the molten metal into the disappearing mold part for casting.

[0010]

Function When the molten metal is poured into the disappearing mold part, the mold disappears due to the heat of the molten metal and is replaced with the molten metal.
The sand particles with high thermal conductivity filled in the hollow part of the disappearing mold absorb the heat of the molten metal faster than the sand particles with low thermal conductivity outside the mold, so the molten metal is cooled from the hollow part side to solidify the molten metal.

As a result, the shape of the cast product is fixed from the inner side to the outer side without distortion, and accurate casting of the jacket structure casting is performed along the mold.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The casting of a basic casting of a ball valve for a water supply pipe as an example of a jacket structure casting will be described as an embodiment of the present invention with reference to the drawings.

Reference numeral 1 denotes an upper split shape obtained by dividing a model of a ball valve for a water supply pipe into upper and lower parts and molding the same with styrofoam.
An interrupt 11 forming a hollow portion A, a through hole 12 forming a water passage portion B, and a joint surface 13 with the lower split piece 2 are formed by joining the lower split piece 2 and the joining surface 13 is formed on the joint surface 13. A fitting protrusion 14 is provided.

An interrupt 21, a through hole 22, a joint surface 23, and a fitting projection 24 are provided on the lower split 2 corresponding to the upper split 1.

Joining surface of split molds 1 and 2 configured as described above
13 and 23 are fitted by the fitting ridge 14, and they are assembled and joined by a paint or an adhesive to form the disappearing mold T. When the fitting protrusion 14 is not formed, the spigot 3 for fixing the positions of the split molds 1 and 2 is attached to an appropriate position as shown in FIG.

Further, when the molten metal is injected, the extinguishing mold T is turned over to inject the molten metal, so that the connecting molten metal inlet 4 for connecting the inflow path of the molten metal and the extinguishing mold T is located on the side injection port side of the extinction mold T. To be joined.

The completed disappearing mold T is filled with sand particles G having a high thermal conductivity such as zircon sand in the hollow portion A, and is attached to the molten metal injecting path 5 so as to conduct heat more than the sand particles G. Grain S mixed with curable resin of low degree
It is put in a mold tank 6 filled with and is embedded in the sand grains S.

When the hollow portion A of the disappearing mold T is in a completely closed state, an outlet for the filled sand grains is provided at an appropriate position.

The mold tank 6 is provided with a decompression mechanism 61 and a vibrating mechanism (not shown) as needed, and vibrates and decompresses the inside of the tank to compact the sand grains S. Of course, the vibration reduction may not be performed depending on the setting situation.

When the setting of the disappearance mold T in the tank is completed, the melt is injected into the melt injection port 51 provided at the beginning of the melt injection path 5, and the disappearance mold T disappears and is replaced with the melt, and the disappearance mold T is lost.
The jacket structure casting is cast according to the shape of.

[0021]

Since the present invention is constructed as described above,
Conventionally, it is possible to cast jacket structure casting at a stretch for double structure products that have been hollowed out from solid castings and products that can be made lightweight by hollowing, streamlining the processing process, lightening the product It has a great effect in terms of materialization and material utilization.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a disappearing mold of a ball valve basic casting of an embodiment.

FIG. 2 is a plan view showing a joint surface of a split mold in the case of fitting without similarly providing a fitting protrusion.

FIG. 3 is a vertical cross-sectional side view of the mold tank in which the disappearance mold is set.

[Explanation of symbols]

 1 Split part on the upper side of the ball valve 11 Interruption that forms the same hollow part 12 Through hole that forms the same water passage part 13 Joint surface with the split part on the lower side 14 Fitting ridge 2 Split part on the lower side of the ball valve 21 Interruption that forms the same hollow part 22 Through hole that forms the same water flow part 23 Joint surface with the split part on the same side 24 Fitting ridge 3 Inlay tool 4 Connecting molten metal inlet 5 Cast molten metal injection path 51 Cast molten metal injection port 6-type tank 61 Decompression mechanism A Hollow part B Water passage part G Sand particles with high thermal conductivity S Sand particles with low thermal conductivity T Disappearance mold

Claims (2)

[Claims] 1. A split mold, which is divided into moldable parts by a disappearing material, is formed and joined to form a disappearing mold having a jacket structure. The hollow part is filled with sand grains having high thermal conductivity, and the outside is hollow. Method for casting a jacket structure casting characterized by wrapping with sand grains having a lower thermal conductivity than the sand grains filled in the casting part and pouring molten metal into the vanishing mold part for casting 2. The method for casting a jacket structure casting according to claim 1, wherein the joining surface of the split mold made of the lost material is formed into a fitting shape.