JPH09136143A - Production of cast iron product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily produce a cast iron product having different property part by beforehand setting a spheroidize-stopping agent into a cavity of a mold corresponding to a flake graphite composition part. SOLUTION: In an upper flask 2a and a lower flask 2b, molding sand 3 is filled in each flask and also, these flasks, the cavity 4 corresponding to a structural material fitted to wheels is formed. in a part 4b corresponding to a brake drum in the cavity 4, a ring-like spheroidize-stopping agent 5 is inserted. Further, a part 4a corresponding to hub H in the cavity 4 is held to an empty space. The spheroidize-stopping agent 5 fills powdery sheroidize-stopping material selected from aluminum, titanium, lead, sulfur and these alloy, etc., into foam styrene lost at molten iron temp. At the time of pouring molten FCD cast iron having ferritic composition into the mold 1 from a runner 3', the part 4b corresponding to the brake drum in the cavity 4 is formed to the FC cast iron and in the other part, the part 4b corresponding to the hub in the cavity 4 is formed to the FCD cast iron.

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 cast iron product comprising a portion having a spheroidal graphite composition and a portion having a flake graphite composition.

[0002]

2. Description of the Related Art Conventionally, for example, a cast iron product a having a wheel mounting structure as shown in FIG. 4 has a hub h to which a drive shaft is mounted and a brake drum d with which a brake shoe b abuts.
It is composed of And in this cast iron product a,
A steel wheel w on which the tire t is mounted is attached by bolts and nuts.

The hub h of the cast iron product a is made of spheroidal graphite cast iron (hereinafter referred to as FCD cast iron), while the brake drum d is made of flake graphite cast iron (hereinafter referred to as FC cast iron). Are assembled by bolts and nuts and integrated.

Therefore, the hub h of the cast iron product a
Can have a predetermined strength, and the brake drum d can have a predetermined thermal conductivity and wear resistance.

[0005]

By the way, in a conventional cast iron product, when it is desired to give a part of the cast iron product the property of a spheroidal graphite composition and another part with the property of a flake graphite composition, However, it has the drawback of requiring an assembling process, as well as being troublesome in that it must be cast.

Therefore, the present invention has been made to solve the above-mentioned drawbacks, and its purpose is to manufacture a cast iron product in which a portion having a spheroidal graphite composition and a portion having a flake graphite composition are integrated. To provide a method.

[0007]

In order to achieve the above object, a method for producing a cast iron product according to the present invention comprises a molten metal having a spheroidal graphite composition in a mold cavity corresponding to a flake graphite composition portion of the cast iron product. A spheroidization inhibitor that inhibits spheroidization is previously placed, and a molten metal having a spheroidal graphite composition is poured into the cavity to produce a cast iron product. Further, the spheroidizing inhibitor is characterized in that a spheroidizing inhibitor such as aluminum or titanium is supported on a material that disappears by the molten metal.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of a cast iron product A manufactured by the method of one embodiment, and the cast iron product is a wheel mounting structure of an automobile (hereinafter, the wheel mounting structure is also referred to as A). FIG.

The wheel mounting structure A has a hub H to which a drive shaft is mounted and a brake drum D with which a brake shoe B abuts, and these are integrally formed. Then, a steel wheel W is attached to the wheel attachment structure A via bolts and nuts, and a tire T is attached to the wheel W.

The portion of the wheel mounting structure A that contacts the hub H is made of FCD cast iron, while the brake drum D is used.
The part corresponding to is formed of FC cast iron.

Therefore, the hub H of the wheel mounting structure A can have a predetermined strength, and the brake drum D can have a predetermined thermal conductivity and wear resistance.

Next, a method of manufacturing the above wheel mounting structure A will be described with reference to FIGS. 2 and 3.

FIG. 2 is a cross-sectional view of the mold 1 used when casting the above-mentioned wheel mounting structure A, which is constructed by stacking an upper frame 2a and a lower frame 2b.

The upper frame 2a and the lower frame 2b are respectively filled with foundry sand 3, and a cavity 4 corresponding to the wheel mounting structure A is formed therein. A runner 3 ′ is connected to the cavity 4, and a molten metal having a spherical graphite composition can be poured through the runner 5.

In the portion 4a of the cavity 4 corresponding to the brake drum D, a ring-shaped spheroidizing inhibitor 5 as shown in FIG. 3 is inserted. Further, the portion 4b of the cavity 4 corresponding to the hub H is kept in the space.

The spheroidizing inhibitor 5 disappears at the temperature of the molten metal and is a styrofoam 5a used in a known disappearance model.
In addition, aluminum (Al), titanium (Ti), lead (P
b), sulfur (S), and a powdery spheroidizing inhibitor 5b selected from these alloys and the like.

When aluminum is selected as the spheroidizing inhibitor 5b, the amount of aluminum is 0.01 to 0.3% (volume ratio, which is well known as an amount that inhibits spheroidal graphite).
The same shall apply hereinafter). Then, the aluminum is planted in advance in the styrofoam 5a. Further, when titanium is selected as the spheroidizing inhibitor 5b, the amount is
It is 0.04 to 0.1%. Furthermore, the amount when sulfur is selected is 0.01-0.5%.

When the molten metal of FCD cast iron is poured from the runner 3'into the mold 1 having the above-mentioned structure, the brake drum D
The portion 4b of the cavity 4 that hits is formed of FC cast iron by the action of the spheroidizing inhibitor 5, while the portion 4b of the cavity 4 that hits the hub H has the F characteristic of the pouring itself.
Formed on CD cast iron.

Therefore, in the cast iron product (wheel mounting structure) A obtained from the mold 1, the portion contacting the brake drum D is formed of FC cast iron, and the portion contacting the hub H is formed of FCD cast iron.

In the above-mentioned embodiment, the spheroidizing inhibitor 5
Was made to use Styrofoam 5a which disappears at the temperature of the molten metal.
A spheroidization inhibiting substance 5b such as aluminum may be arranged in advance in the portion 4a of the cavity 4 that contacts the brake drum D and the molten metal may be poured.

However, when a disappearing material such as expanded polystyrene 5a is used as in this embodiment, it is possible to surely and uniformly form FC cast iron.

Although the polystyrene foam 5a is used as the material that disappears at the temperature of the molten metal, other materials can be selected as long as they disappear at the temperature of the molten metal. Furthermore, although the wheel mounting structure is used as the cast iron product, other cast iron products may of course be used.

[0023]

The method for producing a cast iron product according to the present invention comprises a spheroidization inhibitor which inhibits spheroidization of a molten metal having a spheroidal graphite composition in the cavity of a mold corresponding to the flake graphite composition portion of the cast iron product. Since the cast iron products are arranged and the molten metal having the spheroidal graphite composition is poured into the cavities to manufacture the cast iron products, the cast iron products having the parts having different properties can be easily manufactured. Further, when the spheroidization-inhibiting substance is supported on the material that disappears by the molten metal, the flake graphite composition can be made surely and uniformly.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view when a cast iron product is used as a vehicle wheel mounting structure.

FIG. 2 is a cross-sectional view of a mold.

FIG. 3 is a perspective view of a spheronization inhibitor.

FIG. 4 is a cross-sectional view of a conventional vehicle wheel mounting structure.

[Explanation of symbols]

 A Cast iron product (wheel mounting structure) H Hub D Brake drum 1 Mold 4 Cavity 5 Spheroidizing inhibitor 5a Styrofoam 5b Spheroidizing inhibitor (aluminum)

Claims (2)

[Claims] 1. A spheroidization inhibitor that inhibits spheroidization of a molten metal having a spheroidal graphite composition is placed in advance in a cavity of a mold corresponding to a flake graphite composition portion of a cast iron product, and the spheroidal graphite composition is placed in the cavity. A method for producing a cast iron product, comprising pouring the molten metal having the product to produce a cast iron product. 2. The method for producing a cast iron product according to claim 1, wherein the spheroidizing inhibitor is a material which disappears by the molten metal and which carries a spheroidizing inhibitor such as aluminum or titanium.