JPH04123862A - Method for casting - Google Patents

Abstract

PURPOSE:To prevent the generation of cavity or shrinkage cavity by including a process to add the thermite agent to a sprue port or feeding head part after pouring the molten metal on the method for making casting by pouring the metal heated and melt to the required mold, cooling and solidifying it. CONSTITUTION:The process to add the termite agent 9 at the sprue 5 or the feeding heads 6, 7 after pouring the molten metal is included. The thermite agent is a mixture of metal oxide and aluminum powder, by adding it, generates a great deal of the reaction heat by the termite reaction. The termite agent is ignited with the molten metal and a great deal of the reacting heat is generated by adding the thermite agent at the sprue or the feeding head after pouring. Therefore, a great deal of heat is supplied to the molten metal of the sprue part or the feeding head part. So the molten metal of the sprue part or the feeding head part is not cooled and solidified fastly, the transmission of the pressure of the feeding head of molten metal is not disturbed, and the generation of cavity or shrinkage cavity is prevented regardless of the shape or wall thickness of casting.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a casting method for manufacturing metal products of various shapes, and more particularly to a method for obtaining perfect castings while preventing defects such as cavities and splinters.

Castings obtained by casting can be produced relatively easily from a variety of metal materials such as iron, copper, and aluminum, and can be made in any shape, size, or thickness, and can be produced in large quantities. It is most widely used as a main component of various machines because it can be applied even in small quantities. However, castings have lower mechanical strength than forged products, and are prone to casting defects such as cavities and splinters that occur during casting, so their uses have been limited. Blow holes and sink marks are mainly caused by insufficient replenishment of hot water during the process of cooling and solidifying hot water, or by insufficient riser metal.

Conventional technology In order to replenish the hot water sufficiently and to ensure the intonation, conventional techniques have been used to prevent hot water from overflowing by providing multiple feeders or mixing a large amount of heat insulating agent into the sand of the mold in the feeder. Efforts were made to prevent premature coagulation.

Problems to be solved by the present invention The conventional method described above completely eliminates casting defects such as cavities and jig.
I was unable to prevent LJ. This is because even if a large number of feeders are provided or a heat insulating agent is mixed, the feeder pressure may be insufficient or the hot water may solidify prematurely depending on the shape and wall thickness of the casting. The lack of intonation low force is also due to premature coagulation at the inlet of the riser, which prevents the pressure of the riser from being reliably transmitted to the hot water inside.

Therefore, the technical problem of the present invention is to prevent the hot water from prematurely cooling and solidifying at the sprue and riser inlet, and to prevent the formation of cavities and cracks in any casting shape or wall thickness. Our goal is to provide a unique casting method.

Means for Solving the Problems The technical means of the present invention taken to solve the above-mentioned technical problems is a method of making a casting by pouring heated molten metal into a desired mold and cooling it to solidify it. It is characterized by including a step of adding a thermite agent to the sprue or riser after the hot water is poured.

The active thermite agent is a mixture of metal oxide and aluminum powder, which causes a thermite reaction when ignited and generates a large amount of reaction heat. By adding Chirumitsu 1~ to the sprue or riser after pouring the hot water, the thermite agent is ignited by the hot water and generates a large amount of reaction heat.

Therefore, a large amount of heat is supplied to the molten metal at the sprue or riser.

Effects of the Invention According to the present invention, since a large amount of heat is directly supplied to the molten metal in the sprue or riser, the molten metal in the sprue or riser does not cool and solidify prematurely. The transmission of hot water pressure is not obstructed, and no matter what shape or wall thickness the casting is, no cavities will occur.

Example An example showing a specific example of the technical means of the present invention will be described.

FIG. 1 shows a state in which casting is carried out, in which upper and lower molds 1 and 2 are fixed with a mold frame 3, and a core 4 is placed inside the molds 1 and 2. Molds 1 and 2 are provided with sprue portions 5 and riser portions 6 and 7. Molten metal is poured into the space formed by the molds 1, 2 and the core 4 from the sprue 5 to perform casting. )8 injected from sprue part 5
The hot water passes through the runner 5a and reaches the space between the core 4 and the riser section 6,
Pushing up to 7. In this case, the first injected molten metal starts to cool and solidify when it reaches the thin wall part, and then the other parts are removed. If hot water is not replenished when the thick wall is finally about to solidify, cavities will occur. In the conventional casting method, when this thick part is finally about to solidify, even if you try to replenish hot water or apply pressure from the sprue part 5 or the riser part 6.7, the narrow part of the sprue part 5 or the riser part 6. Part of the molten metal at the ends of the molten metal parts 6 and 7 cools and solidifies, making it impossible to replenish or pressurize the molten metal sufficiently, resulting in cavities and sink marks. In the present invention, by including the step of adding the thermite agent 9 to the sprue part 5 or the feeder parts 6 and 7 after pouring, the thermite agent 9 is ignited by the molten metal, causing a thermite reaction, and a large amount of reaction heat is generated. In order to prevent the molten metal from prematurely cooling and solidifying in the narrow part of the sprue 5 and the ends of the feeder parts 6 and 7, the replenishment of hot water and the pressurization from the feeder parts are carried out reliably. , no cavities or sink marks occur.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a casting showing an embodiment of the casting method of the present invention. 1: Upper mold 2: Lower mold: Core 5: Sprue part 6°: Riser part: Thermite agent

Claims (1)

[Claims] 1. A casting method in which heated and molten metal is poured into a desired mold and cooled and solidified to produce a casting, which includes the step of adding a thermite agent to the sprue or riser after pouring.