JPS6167563A - Casting method by heating casting mold - Google Patents

Abstract

PURPOSE:To reduce the cost of a casting mold by placing a heating agent along the inside surface of a sand casting mold, and thereafter, charging a molten metal, and delaying the cooling of the surface of the molten metal through heating of the heating agent. CONSTITUTION:A heating casting mold is constituted by forming a casting space A by upper and lower sand casting molds 2, 3, and applying a heating agent to its inside surface side. The heating agent 5 is constituted of an easy oxidizing metal such as A&l, an oxidizing agent such as iron oxide, etc., an oxidation accelerating agent, a silicon material, etc., and executes heating of <=2,000 deg.C by a thermit reaction by contacting a molten metal. By this heating, cooling of the surface of the molten metal in the casting mold is delayed, and sand mold casting of a thin casting can be executed. Accordingly, the cost is reduced remarkably, comparing with use of a conventional metallic mold.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to thin castings or thin parts of aluminum, aluminum alloys, copper, copper alloys, cast iron, cast steel, and alloys thereof. The present invention relates to a casting method suitable for casting a cast product having the following properties.

[Conventional technology]

When casting thin castings, the molten metal contacts the mold with a large surface area relative to its volume, which causes it to cool early and lose its fluidity.
The only method available was the die-casting method using a metal mold, and casting using a sand mold had not been done.

[Problem that the invention seeks to solve]

Casting by the die-casting method as described above requires preparing an expensive mold for each product, making it unsuitable for a casting method for high-mix, low-volume production.

The present invention provides a casting method that uses sand molds, which are advantageous in terms of cost, as molds for high-mix, low-volume production, and is capable of casting thin castings, or castings with thin parts. Especially for that purpose.

[Means for solving problems]

The technical means of the present invention taken to solve the above problems is to place an exothermic agent that causes an exothermic reaction at the temperature of the molten metal in advance along the inner surface of a sand mold, and to inject the molten metal into the sand mold. Therefore, the cooling of the surface of the molten metal poured into the sand mold is delayed due to the heat generated by the exothermic agent.

[For production]

As a result of taking the above technical measures, the exothermic agent causes an exothermic reaction upon contact with the injected molten metal, and the heat heats the molten metal surface, or reduces the temperature difference with the #I molten metal surface,
This delays the cooling of the molten metal.

〔Effect of the invention〕

As a result of the above action, the cooling of the molten metal is delayed and the fluidity of the molten metal is ensured, making it possible to cast thin products or products with thin parts even though the casting method uses a sand mold. Ta.

〔Example〕

The present invention will be explained in detail below.

First, as shown in Fig. 2, a sand mold +11 consisting of an upper mold (2) and a lower mold (31, etc.) is formed using appropriate molding sand, and the sand layers (2a) and (3a) of the sand mold fl+ are formed. Apply the exothermic agent (5) to the entire area of the casting space (4) formed on the inner surface side or to the part corresponding to the thin wall part, so that the layer of the exothermic agent (5) is located at the innermost side of the casting space (4). to construct a heat generating mold (see Figure 1).

Molten metal is injected from the sprue (5) of the exothermic mold configured as described above, and a thin cast product of a desired shape is cast within the casting space (4). Reference numeral (7) in the figure is a feeder opening.

The exothermic agent (5) includes an exothermic accelerator consisting of an easily oxidizable metal such as aluminum, an oxidizing agent such as iron oxide, palicum chloride, potassium chloride, magnesium, etc., and a refractory material such as silicon or chamotte. Knead appropriate amounts at a time to generate heat due to thermite reaction (20σ0°(:,,2JOO℃)
degree). In addition, for refractory materials such as silicone or ikechamotte, the refractory material remains in the casting space (
4) The peripheral surface of the button remains in the state of a porous layer, and the casting space (4)
This is used to maintain the dimensional accuracy of the casting, but it can be omitted if the cast product does not require much dimensional accuracy.

In addition, it is not necessary to use all of the exothermic accelerators mentioned above, and it is possible to select and use an appropriate one to obtain the required exothermic temperature or exothermic reaction rate.

The exothermic agent (5) may be used in an appropriate amount so that the molten metal flows smoothly to every corner of the casting space.

For example, in the case of flat cast iron with a thickness of about j '' - J ml, suitable fluidity was obtained at about O,j~/h, but this may depend on the type and performance of the exothermic agent (5), or , varies greatly depending on the material, shape, etc. of the cast product, so it is desirable to use an appropriate amount each time.

In addition, in order to position the exothermic agent (5) on the inner surface of the mold,
Instead of applying it with a brush or spray as in the previous embodiment, as shown in Figures 3 and 4, a heat-generating agent (5) solidified in the form of a plate or granules is cast and placed facing the inner space. ,
They may be attached using an appropriate adhesive means such as a resin adhesive (8), or they may be scattered at appropriate locations rather than covering the entire area of the casting space (4).

In the embodiments shown in FIGS. 8 and 4, the exothermic agent (5) is placed over the surface of the coating agent (4) applied to the inner surface of the sand mold (1). In the case of the embodiment as well, the exothermic agent (61) may be placed directly on the surface of the sand layers (2a) and (3a) without using the coating agent (4).

The exothermic agent (5) is preferably one that generates a high temperature, such as one that causes a thermite reaction, but even if it does not generate a high enough temperature to add heat to the molten metal, it may be used at a temperature that is slightly lower than the temperature of the molten metal. It may be one that generates enough heat to slow down the cooling rate of the molten metal.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIG. 1 is a partially enlarged cross-sectional view of a heat-generating mold, FIG. 2 is a schematic cross-sectional view of a heat-generating mold, and FIGS. 8 and 4 show different implementations of the setting of a heat-generating agent. This is an example. il+...Sand mold, (5)...Exothermic agent.

Claims (1)

[Claims] An exothermic agent (5) that causes an exothermic reaction at the temperature of the molten metal is placed in advance along the inner surface of the sand mold (1), and the molten metal is poured into the sand mold (1) to remove the exothermic agent (5). A casting method using an exothermic mold in which cooling of the surface of the molten metal poured into the sand mold (1) is delayed by the heat generated by the sand mold (1).