JPH01113162A - Production for fiber reinforced composite casting body - Google Patents

Abstract

PURPOSE:To improve molten metal flow, to obtain composite casting having uniform quality and to improve mechanical strength and wear resistance by setting a formed body, which directions of all fibers are arranged to horizontal and density of the fibers is equal, and casting the metal of Al alloy, etc., to the mold. CONSTITUTION:Inorganic staple material 1 is charged into liquid and stirred and also the staple material 1 is filtered in the liquid by plug, clothes, etc., depositted and coagulated and further, cut in order to uniformize to granulate to the fixed size. This fiber grain is charged into the mold having the prescribed shape and compressed to coming to the prescribed fiber volumetric ratio, and as the fiber grains, which naturally arrange to horizontal direction and have equal size, are used, the fiber formed body 2 having uniform quality is formed. This formed body 2 is set to the prescribed position in the mold and by casting the metal 3 of Al alloy, etc., into the mold, good molten metal 3 flow is obtd. because of arrangement of the orientation and density of the fiber. The molten metal is sufficiently penetrated into the void in the fiber formed body 2 and also, as bending fiber material is not contained, the mechanical strength and the wear resistance are improved.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for manufacturing a fiber-reinforced composite cast body, which involves injecting metal hot water into a fiber molded body formed by molding an inorganic short fiber material with a binder.

Conventional technology A method for manufacturing a fiber composite cast body in which metal hot water is injected into the space of a fiber molded body to obtain excellent mechanical strength, wear resistance, etc. in local parts of the cast body is disclosed in Jikai 1'I85 B-93560. issue,
There is Japanese Patent Application Laid-open No. 52-128832, etc. Said Japanese Unexamined Patent Publication No. 58
-93560 is a ring-shaped ia A! with a rectangular cross section in the manufacture of pistons for internal combustion engines. This is a method for manufacturing a fiber composite cast body in which a molded body is set at a predetermined position in a mold, and an aluminum alloy or the like is cast into the mold to locally strengthen the fibers. This is a method for producing a cast body, in which a molded body of an inorganic member is molded in order to provide heat insulation properties to a piston, a combustion chamber, etc., and the molded body is composited with a part of an aluminum or magnesium alloy casting. However, since composite castings made by this conventional manufacturing method are compression molded using matte or bulk inorganic short fibers, even when aluminum alloy is cast, it does not penetrate sufficiently into the fiber moldings, so it is not mechanically possible. It is easy to cause variations in strength, wear resistance, etc., and in particular, the mechanical strength tends to be significantly different between the horizontal direction and the vertical direction, and there is a risk of breakage during use. For this reason, by adding a binder to a large number of inorganic short fibers deposited in the form of fluff in advance and bonding and molding them into a molded body of a predetermined shape, it is possible to make it easier for the metal hot water to penetrate into the fiber molded body. The present inventor has proposed a method for producing a ta-male reinforced composite cast body that can further improve strength, wear resistance, etc. in Japanese Patent Application No. 62-22457.

Problems to be Solved by the Invention However, in the mfar shape made from fluff shapes in this Japanese Patent Application No. 62-22457, the fiber volume percentage must be 18% in order to bring the adjacent fluffs into sufficient contact with each other. The above is necessary, and only a part of the molded body with a fiber volume ratio of 10 to 20%, where fiber reinforcement is good, can be formed, and it is difficult for the metal molten metal to penetrate evenly unless the casting pressure is relatively high. The L ball made by intertwining the fibers contains an extremely large number of bent fibers, so it has drawbacks such as poor heat fatigue resistance.

Means for Solving the Problems The present invention was made in order to eliminate the above-mentioned drawbacks. Specifically, the inorganic 1υffl male material deposited in advance in the horizontal direction is molded with a binder into a molded body of a predetermined shape. By setting a metal at a predetermined position in a mold and casting a metal such as an aluminum alloy into the mold, the metal molten metal penetrates evenly into the molded body even at a relatively low casting pressure, and the fiber composite part of the resulting cast body is Provided is a method for producing a fiber-reinforced composite cast body which has extremely excellent mechanical strength and wear resistance, and has improved thermal fatigue resistance.

Function: The fibrous molded product produced in the manufacturing process of the present invention is obtained by adding inorganic short fiber material into a liquid and stirring it, and then straining the inorganic short fiber material from the liquid using a sieve or cloth, allowing it to accumulate and coagulate. In order to homogenize the density, the accumulated and agglomerated fibers are crushed by hand or cut with a knife to granulate them into a certain size, and the fiber granules are placed in a mold with a predetermined shape to form the predetermined fibers. By compressing until the volume ratio is reached, if the direction of the fiber grains is not horizontal, the fiber grains will naturally become horizontal due to the pressure, and since fiber grains of the same size are used, a fiber molded product with a homogeneous fiber density can be formed. . In addition, the initial specific gravity of the HA fibers in the present invention is 0.02 for conventional mat-like fibers and 0.03-0.05 for bulk-like fibers, but 0.0, which is almost the same as that of pilling. Since it is .10 to 0.13, the pressure applied when compression molding is performed to produce a fiber molded product is small.
In addition, since the compression ratio is small, it is extremely easy to mold a molded product, and a product with a large aspect ratio can also be obtained.

By setting this molded body at a predetermined position in a mold and casting metal such as aluminum alloy into the mold, the flow of the metal molten metal is improved because the directionality and density of the fibers are uniform. The la fiber material sufficiently penetrates into the space of the LA fiber molded product and contains almost no bent fiber material, so it is possible to mold a molded product with a fiber volume ratio in the range of 10 to 20% with good H/A fiber reinforcement.

Examples Below, examples of the present invention will be explained based on the drawings. First, an inorganic short film is placed in a mixing container equipped with stirring χ in which a liquid such as water or alcohol is pre-filled to a concentration of 5% by volume or less. Pour the fiber material (1) into the liquid while stirring at a slow speed that does not allow the fibers to get entangled. short fiber material (
1) Disperse and suspend. The inorganic layer H & fiber material (1) includes silica-alumina Ha fiber material in addition to normal alumina fiber, graphitic FA fiber material, silicon carbide fiber in addition to normal carbon fiber, and each of them may be used individually. In this case, the length of the fibers may be several c11100. Commercially available short fiber materials may be used as they are, but those cut into lengths of 1 cm or less should be used. You can also do it.

Thereafter, the dispersed and suspended state is filtered through a metal sieve or cloth, and the 1 m short fiber material (1) is deposited and aggregated thereon. At this time, the IA A material (1) can be crossed in a state where it is all lying down without standing vertically, so the fibers are piled up and aggregated so that the direction of the fibers is horizontal, and the short fiber material (1) is similar to the conventional fluff. Short fiber material (L) bent in this manner is hardly seen. still,
The cloth has good liquid permeability, and the opening of the metal sieve is preferably in the range of 0.043 to 3+sm.

After the inorganic short fiber material (1) is deposited and agglomerated, it is separated from a metal sieve or cloth, and granulated into a certain size by crushing it by hand or cutting it with a knife in the atmosphere. do. The size of the tam grain at this time is length, width, height,
Alternatively, the diameter should be in the range of 0.1 to 3+sm. The fiber particles are housed in a mold of a predetermined shape, for example, a circular shape, and then silica sol is formed.

A binder such as acidic or basic aluminum chloride is added to sufficiently moisten the material, and the fiber particles are compressed from the top of the mold to a predetermined bulk specific gravity. 80-10 when compressed
By drying at a temperature of 0°C and then firing at a temperature of 800 to 1000°C, a molded product with desirable properties, that is, the direction of the fibers is aligned horizontally and the density of the fibers is homogeneous (
2) can be obtained. Next, the fired molded body (2) is placed in a predetermined position in the mold, for example, in the head part for a piston part (A), and metal hot water such as aluminum alloy is injected to form a fiber-reinforced composite cast body (A). is cast (5th
(see figure), it is desirable to use an appropriate casting method during casting in which pressure is applied so that the hot water of the metal (3) sufficiently penetrates into the internal space of the molded body (2).

Table 1 shows the fiber molded articles (
2) Fiber made from 1 pill shape! II & Shape (2), 1 cm x 1 cm using a razor from a fiber molded body made from a mat shape and a fiber molded body made from a bulk shape.
The sample pieces were divided into 100 pieces each measuring 1.5 cm in diameter, and the weight of each piece was measured. The deviation value was determined. The results are shown below.

:51 Table (Experiment 1) Note that the conditions at this time were that each fiber molded body (2) was 10
Dry at 0℃, heat and bake at 700℃, diameter is 15cm
, thickness 1.5 cm, Fa male volume fraction 10%, and the inorganic short fiber material (1) has a diameter of 3.5 cm. uI8. Using alumina short fiber material with a length of 1 to 2 cm, and in the production method of the present invention, in a dispersed and suspended state, the alumina fiber material has a mesh size of 1+i.
Use a metal sieve of size 1.

Table 2 shows that when the disk-shaped fiber m molded body (2) is compression molded, the fiber volume is -J20%, other detailed conditions are molded according to the conditions in Table 1, and after drying, Each molded body (2) heated and fired at 700°C is set in PIffi, and the mold is filled with AI-12%5i-0.5%) at 700°C.
From the composite cast part of the piston component casting (A) as shown in Figure 5 obtained by pouring 1 g of 42% Cu alloy molten metal, four rod-shaped samples were taken in each of the diameter and height directions of the casting (A). The result of cutting out a piece and performing a tensile test is shown.The fiber molded article (2) made from the pill shape has a fiber volume percentage of 18%.
Since the above is necessary, a fibrous material of m*20% is preformed from the beginning.

Table 2 (Experiment 2) 4i Kz/am" Table 3 shows the cast body (A) obtained by casting AI-12%S i -0.5%M, -2% Cu alloy hot water. A disk shape with a diameter of 92 a + m and a thickness of 15 mm was cut from the composite cast part of , and the thermal fatigue test process shown in Fig. 2 was set as one cycle (=60 seconds), and cracks first appeared in each fiber composite cast body (A). The results of comparing the number of cycles up to this point are shown.

Table 3 (Experiment 3) From the results of Experiments 1 to 3, the composite cast body (A) made according to the present invention showed almost no directionality in mechanical strength in the composite part and was extremely homogeneous. It was confirmed that there was a significant improvement in thermal fatigue strength.

Effects of the Invention As described above, the manufacturing method of the present invention involves setting a molded body (2) in which the fiber direction is horizontal and having a uniform fiber density in a mold, and placing a metal such as an aluminum alloy in the mold. (3)
By casting, the fiber density is extremely homogeneous compared to conventional fiber moldings made from mat or bulk shapes, so the flow of the metal metal is good even at relatively low casting pressure, and it is sufficient to fill the space of the m-male. A homogeneous composite cast body (A) can be produced by infiltrating the metal (3) into the composite cast body (A), which improves mechanical strength and wear resistance.

In addition, the production method of the present invention enables a fiber molded article (
2) becomes possible, and a fiber molded article (2) with good fiber reinforcement and a fiber volume ratio of 10 to 20% can be easily produced.

Moreover, since the fiber molded product (2) contains almost no bent fiber material (1), it has twice the durability in the heat fatigue test (Experiment 3) compared to the conventional product made from fluff. It shows the number of cycles, and also in a fatigue test by rotary surface bending, the fatigue strength is improved by 40% compared to the one made from a pill shape, and the heat fatigue resistance properties etc. are significantly improved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an overview of an example of the manufacturing process of the present invention, FIG. 2 is a diagram showing the contents of a thermal fatigue test, and FIG. 3 is a perspective view showing an example of a tli-formed product according to the present invention. FIG. 4 is a perspective view showing a conventional molded product made from a fluffy shape, and FIG. 5 is a partially cutaway front view IZ showing an example of a part made according to the present invention. (1)...Non-4yj, short fiber material (?)...Molded object (3)...Metal (2) Patent application agent Hiroshi Matsuoka, ',, -'j,, +j U, 4
1/ Fig. 7] Lid [ Fig. 3 Fig. 4 Fig. c

Claims (1)

[Claims] The inorganic short fiber material (1) deposited in the horizontal direction in advance is molded with a binder into a molded body (2) of a predetermined shape, the molded body (2) is set at a predetermined position in a mold, and an aluminum alloy is placed in the mold. A method for manufacturing a fiber-reinforced composite cast body, characterized by casting by casting a metal (3) such as.