JP2003326346A - Method for producing cast iron-made cast-in member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the stickiness on the other metal which can arrange a plurality of projections having a desired shape of undercut part on the surface of a cast-in member in a simple process. <P>SOLUTION: Facing agent 30 is coated on the inner peripheral surface 34 of a mold 30. The facing agent 36 is formed as a plurality of spherical parts 36b, and molten cast iron 40 is poured into this mold 30 while rotating the mold 30 under state of replacing into inert gas in the mold 30. The molten iron 40 is filled up to the undercut parts 36c while covering the spherical parts 36b. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to other metals, for example,
The present invention relates to a method for manufacturing a cast iron cast member that is cast around an aluminum alloy.

[0002]

2. Description of the Related Art For example, in a cylinder block constituting an automobile engine, an aluminum alloy cylinder block is generally used for weight reduction. At that time, a cylinder liner (casting member) made of cast iron is incorporated corresponding to the sliding surface which is required to have abrasion resistance and the like. Similarly, in the brake drum, a cast iron shoe (casting member) is used.

By the way, when a cast iron member made of cast iron is cast around another metal, for example, an aluminum alloy, the adhesion between the cast iron member and the aluminum alloy and the filling property of the aluminum alloy are required. . Therefore, for example, as disclosed in Japanese Patent Laid-Open No. 2001-170755, the maximum height of surface roughness is 65 μm to 260 μm.
There is known a cast iron member for a cast body having a cast face having an average distance of 0.6 mm to 1.5 mm.

With this, when the aluminum alloy is die-cast on the outer periphery of the cast-molded member, it is possible to obtain a cast-molded product having a good filling property of the aluminum alloy into the irregularities and an excellent adhesion with the aluminum alloy. It is possible.

[0005]

By the way, in the above-mentioned prior art, when forming a desired cast face, silica sand having an average particle size of 0.05 mm to 0.5 mm is used as a mold coating material.
% By mass to 45% by mass, 10% by mass to 30% by mass of silica flower having an average particle diameter of 0.1 mm or less, and 2% by mass of a binder.
The turbid liquid which mixed 10 mass% and 30 mass% -60 mass% of water is used.

Therefore, according to this prior art, when the coating agent is applied to the heated inner surface of the mold and then dried, a large number of minute pits are generated due to the vapor holes generated from the coating material, and molten cast iron is poured. The molten metal forms a cast face having a needle-shaped protrusion corresponding to the depression.

In this case, as shown in FIG. 8, the cast-face member 1 is formed with a cast-face surface 3 having needle-like projections 2, and the cast-face surface 3 is cast into an aluminum alloy material 4. As a result, a cast product 5 is obtained. At that time, since the plurality of needle-shaped protrusions 2 are provided on the cast-molded surface 3,
Relative displacement in the direction of arrow A does not occur and residual stress can be reduced.

However, in the above cast-molded product 5, peeling easily occurs between the cast-molded member 1 and the aluminum alloy material 4 along the arrow B direction parallel to the needle-shaped protrusions 2. As a result, the adhesion between the cast-in member 1 and the aluminum alloy material 4 is reduced, and the contact area between the cast-in member 1 and the aluminum alloy material 4 is reduced, resulting in a decrease in thermal conductivity. It has been pointed out.

The present invention solves this kind of problem, and is made of cast iron capable of effectively improving the adhesion with other metals by a simple process and maintaining a desired thermal conductivity. An object of the present invention is to provide a method for manufacturing a cast-molded member.

[0010]

In the method for manufacturing a cast iron cast member according to the present invention, a mold coating material containing a heat insulating material, a binder, a release agent, a surfactant and water is applied in a mold. After that, the inside of the mold is replaced with an inert gas atmosphere. In this state, while the mold is being rotated, the molten cast iron is poured into the mold, so that the surface of the stuffed product has a substantially conical undercut portion that expands outward. A plurality of protrusions is provided.

That is, when the mold coating material is applied to the mold, a part of the mold coating material forms a spherical portion by the surface tension under the action of the surfactant contained in the mold coating material. Therefore, the mold material is provided with a large number of spherical portions having undercut portions from the mold surface corresponding to the inner surface of the mold.

Next, since the inside of the mold is replaced with an inert gas atmosphere, the formation of an oxide film on the surface of the molten metal can be prevented, and the flowability of the molten metal in the mold becomes effective. improves. Therefore, the molten metal fills the spherical portion of the mold coating material smoothly and reliably up to the undercut portion, and the shape of the mold coating material can be accurately transferred.

As a result, the cast iron stuffed member made of cast iron can surely be provided with a plurality of protrusions having a substantially conical undercut portion which expands outward on the surface of the cast stuffed member, such as an aluminum alloy. Adhesion with other metals and thermal conductivity are effectively improved.

Further, the coating material is made of diatomaceous earth as a heat insulating material.
0% by mass to 35% by mass, 1 bentonite as a binder
% To 7% by mass, 1% to 5% by mass of the release agent, 5 ppm to 50 ppm of the surfactant, and the balance water.

If the amount of diatomaceous earth is less than 20% by mass, the effect as a heat insulating material cannot be obtained, while if it exceeds 35% by mass, the viscosity increases and the fluidity decreases. If the amount of bentonite is less than 1% by mass, sufficient caking properties cannot be obtained and other substances are separated, while if it exceeds 7% by mass, the viscosity is high and the disintegration property is reduced.

If the amount of the releasing agent is less than 1% by mass, the effect as the releasing agent cannot be obtained, while if it exceeds 5% by mass, the structural water contained in the composition becomes a gas due to the heat of the molten metal during casting. The gas defect may occur in the cast iron cast member. If the surfactant content is less than 5 ppm,
While the shape maintaining effect cannot be obtained, when it exceeds 50 ppm, foaming occurs.

Furthermore, the mold rotation speed of the mold is GNo. 25-GNo. It is set to 35. Mold rotation speed is GNo. If it is less than 25, the spherical portions of the mold coating material are less likely to be crushed and the spacing between the spherical portions is increased. Therefore, it is not possible to secure a desired amount of undercut on the projection of the cast iron cast member, and sufficient adhesion cannot be obtained. On the other hand, the mold rotation speed is GNo. When it exceeds 35, the spherical portions of the mold coating material are more crushed and the distance between the spherical portions is narrowed.
Therefore, in the projection of the cast iron cast member, the diameter of the small diameter portion becomes considerably small corresponding to the space between the spherical portions, and the small diameter portion may be broken.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a partial disassembly of a cylinder block 12 around a cylinder liner (cast iron cast gurney member) 10 manufactured by a method of manufacturing a cast iron cast gurney member according to an embodiment of the present invention. It is isometric view explanatory drawing.

The cylinder block 12 is provided with, for example, an aluminum alloy block 14 in order to reduce the weight. The cylinder block 12 is manufactured by casting the aluminum alloy block 14 around the cast iron cylinder liner 10.

The cylinder liner 10 will be described later.
It is manufactured using cast iron by the centrifugal casting method. As schematically shown in FIG. 2, a plurality of projections 20 having a substantially conical undercut portion 18 that widens outward is provided on a cast-face surface 16 provided on the outer peripheral surface of the cylinder liner 10. Is provided.

As shown in FIG. 3, the cylinder block 12
Then, the gap between the protrusions 20 of the cylinder liner 10 is filled with the aluminum alloy block 14 so that the spherical joint 2
2 is formed.

Next, a method of manufacturing the cylinder liner 10 thus constructed will be described.

First, as shown in FIG. 4, a mold (mold) 30 constituting the centrifugal casting apparatus has, for example, a cylindrical shape, and is rotatably supported via a drive unit (not shown). .

Therefore, the mold rotation speed of the mold 30 is GN.
o. 25-GNo. While rotating within the range of 35, the mold coating material 36 is applied to the inner peripheral surface 34 of the mold 30. The mold coating material 36 contains a heat insulating material, a binder, a release agent, a surfactant, and water. Specifically, as the heat insulating material, for example, diatomaceous earth is 20% by mass to 35% by mass, and as the binder, for example, bentonite is 1% by mass to 7% by mass,
Release agent is 1% by mass to 5% by mass, and surfactant is 5 ppm by mass.
50 ppm, the balance being set to water.

At the time of applying the coating material 36, the coating material 36
Under the action of the surfactant contained in the above, a spherical portion 36b is formed in which a part of the mold coating material 36 bulges outward from the mold coating surface 36a by surface tension. Therefore, the mold material 36 is provided with a large number of spherical portions 36b having an undercut portion 36c from the mold surface 36a corresponding to the inner peripheral surface 34 which is the mold surface.

Next, the atmosphere in the mold 30 is, for example,
The atmosphere is replaced with an inert gas atmosphere such as argon gas. In this state, the mold 30 has a mold rotation speed of GNo. 100 ~
GNo. While rotating within the range of 135, mold 30
A cast iron melt 40 is poured therein.

Therefore, the molten metal 40 is filled so as to cover the spherical portion 36b of the molding material 36, and the shape of the molding material 36 is transferred. As a result, the cast surface 16 having a cylindrical shape and having a plurality of protrusions 20 on the outer peripheral surface is provided in the mold 30.
The cylinder liner 10 in which is formed is manufactured.

In this case, in this embodiment, the mold coating material 36 contains a heat insulating material, a binder, a release agent, a surfactant and water. The heat insulating material is, for example, diatomaceous earth, and has a function of optimally maintaining the temperature of the molten metal 40 poured into the mold 30. The diatomaceous earth is set to 20% by mass to 35% by mass.
If the amount of diatomaceous earth is less than 20% by mass, the effect as a heat insulating material cannot be obtained, while if it exceeds 35% by mass, the viscosity increases and the fluidity decreases.

The binder has a function of holding the shape of the spherical portion 36b of the mold coating material 36, and bentonite is used, for example. This bentonite is set to 1% by mass to 7% by mass. If the amount of bentonite is less than 1% by mass, sufficient caking properties cannot be obtained and other substances are separated, while if it exceeds 7% by mass, the viscosity is high and the disintegration property is reduced.

The release agent is set to 1% by mass to 5% by mass. If the release agent is less than 1% by mass, the effect as a release agent cannot be obtained, while if it exceeds 5% by mass, the structural water contained in the composition becomes a gas due to the heat of the molten metal 40 at the time of casting, and the cylinder liner. There is a possibility that a gas defect may occur in 10.

The surfactant has a function of increasing the surface tension of the mold coating material 36 and maintaining the shape of the spherical portion 36b.
The surfactant is set to 5 ppm to 50 ppm. If this surfactant is less than 5 ppm, the shape-maintaining effect cannot be obtained, while if it exceeds 50 ppm, foaming occurs.

Further, in the present embodiment, after the application of the mold coating material 36 to the inner peripheral surface 34 of the mold 30, the molten metal 40 is poured with the inside of the mold 30 being replaced with the active gas atmosphere. . Therefore, an oxide film is not formed on the surface of the molten metal 40 poured into the mold 30, and the flowability of the molten metal 40 in the mold 30 is effectively improved. Therefore, the molten metal 40 covers the spherical portion 36b of the mold coating material 36 and is smoothly and surely filled up to the undercut portion 36c, and the shape of the mold coating material 36 can be accurately transferred.

As a result, the cylinder liner 10 can surely be provided with the plurality of projections 20 having the substantially cone-shaped undercut portion 18 that expands outward on the cast-molded surface 16. Therefore, it is possible to effectively improve the adhesion and the thermal conductivity with the aluminum alloy block 14 that surrounds the cylinder liner 10.

Further, in this embodiment, as schematically shown in FIG. 2, the undercut portion 18 of each projection 20 is formed in a substantially conical shape, and the circumferential direction (arrow X direction) and the axial direction of the cylinder liner 10 are formed. It also has an undercut shape with respect to the (arrow Y direction). Therefore, as shown in FIG. 3, in the cylinder liner 10 and the aluminum alloy block 14, the protrusion 20 of the cylinder liner 10 and the spherical joint portion 22 of the aluminum alloy block 14 are in close contact with each other.

As a result, the cylinder liner 10 and the aluminum alloy block 14 are prevented from being displaced in the direction of arrow A, that is, from being displaced to reduce the residual stress generated in the inter-axis portion 15 of the cylinder block 12, and Arrow B
It is possible to prevent the deviation of the direction, that is, peeling, and to prevent the mutual adhesion strength from decreasing as much as possible.

Moreover, the contact surface area between the cylinder liner 10 and the aluminum alloy block 14 increases. Therefore, the heat generated in the cylinder liner 10 due to sliding or the like can be efficiently transmitted to the aluminum alloy block 14, and the heat dissipation can be improved.

Further, the mold rotation speed of the mold 30 is set to GNo. 25-GNo. It is set to 35. Mold rotation speed is GNo. When it is less than 25, as shown in FIG. 6, the spherical portions 36b of the mold coating material 36 are less crushed, and the interval H1 between the spherical portions 36b becomes wider. As a result, the protrusion 20 of the cylinder liner 10
In addition, a desired amount of undercut cannot be secured, and sufficient adhesion cannot be obtained.

On the other hand, the mold rotation speed is GNo. If it exceeds 35, as shown in FIG.
Becomes larger, and the distance H2 between the spherical portions 36b increases.
Becomes narrower. Therefore, the diameter of the small diameter portion of the projection 20 of the cylinder liner 10 is considerably reduced corresponding to the space between the spherical portions 36b, and the small diameter portion may be broken.

In this embodiment, the cylinder liner 10 of the cylinder block 12 is used as the cast iron member made of cast iron, but the present invention is not limited to this, and is also applied to a brake shoe of a brake drum, for example. be able to.

[0040]

According to the method for producing a cast iron cast-in member according to the present invention, a spherical protrusion having a substantially conical undercut portion is surely formed on the cast-iron surface of the cast iron cast-in member in a simple process. It can be provided, and, for example, the adhesion to other metals such as an aluminum alloy and the thermal conductivity are improved.

[Brief description of drawings]

FIG. 1 is a partially exploded perspective explanatory view of a cylinder block that surrounds a cylinder liner manufactured by a method for manufacturing a cast iron cast-in member according to an embodiment of the present invention.

FIG. 2 is a partially enlarged perspective view schematically showing a protrusion of the cylinder liner.

FIG. 3 is a partial cross-sectional explanatory view of the cylinder block.

FIG. 4 is an explanatory diagram when applying a mold coating material to a mold.

FIG. 5 is an explanatory view when pouring molten metal into the mold.

FIG. 6 is an explanatory diagram of a mold coating material when the rotation speed is small.

FIG. 7 is an explanatory diagram of a mold coating material when the number of rotations is large.

FIG. 8 is an explanatory view of a conventional cast-molded member.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Cylinder liner 12 ... Cylinder block 14 ... Aluminum alloy block 16 ... Casting surface 18, 36c ... Undercut part 20 ... Protrusion 22 ... Spherical joint 30 ... Mold 34 ... Inner peripheral surface 36 ... Coating material 36a ... Coating type Surface 36b ... Spherical part 40 ... Molten metal

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) B22C 9/06 B22C 9/06 D B22D 13/02 501 B22D 13/02 501B 19/00 19/00 G 19/08 19 / 08 E F02F 1/00 F02F 1/00 C F term (reference) 3G024 AA25 AA26 BA04 FA14 GA03 GA06 HA02 HA07 4E092 AA06 AA36 CA03 DA02 EA10 GA02 4E093 NB10 UA02 UA03

Claims (3)

[Claims] 1. A step of applying a coating material containing a heat insulating material, a binder, a release agent, a surfactant and water into the mold, and a step of replacing the inside of the mold with an inert gas atmosphere. While rotating the mold coated with the mold coating material, by pouring molten metal of cast iron into the mold, a substantially conical undercut portion that expands outward on the surface of the cast iron is formed. And a step of providing a plurality of protrusions having the same, and a method for manufacturing a cast iron cast-gurgling member, comprising: 2. The manufacturing method according to claim 1, wherein the mold coating material comprises diatomaceous earth in an amount of 20% by mass to 35% by mass as the heat insulating material, and bentonite in an amount of 1% by mass to 7% by mass as the binder. A method for producing a cast iron cast member, wherein the mold agent is set to 1% by mass to 5% by mass, the surfactant is set to 5 ppm to 50 ppm, and the balance is set to the water. 3. The manufacturing method according to claim 1, wherein the mold rotation number of the mold is GNo. 25-GNo. 35 is set to 35.