JPS5829564A - Production of fiber reinforced composite body - Google Patents

Abstract

PURPOSE:To obtain composite bodies which retain the curved parts of small curvature and abruptly shape changing parts without collapse of shapes in a process for production wherein the wax in a molding of mixtures of short fibers and wax is eluted by changing the mixing ratios of the fibers according to the change in the shape. CONSTITUTION:Inorg. or metallic short fibers 2 are put in molten wax 4 and >=2 kinds of mixtures having different mixing ratios of fibers are prepared. Such mixtures are packed in dies 5. Here, the fiber mixture of low fiber contents is packed in the cavities corresponding to the curved parts of small curvature and abruptly shape changing parts enclosed by the circles A, B of a connecting rod. The fiber mixture of high fiber contents is packed in the approximately linear parts or the portions having no abrupt shape changes other than said parts. The mixtures are pressed, whereby a molding 6 is obtained. The collapse of the shapes in the ports in the circles A, B is prevented surely. Thereafter, a refractory layer 9 is formed on the outside circumference of the molding 6, and the molding is heated to elute the wax 4. Metal is charged into the cavities in the layer 9 packed with the fibers, and the mold 10 is removed, whereby a fiber-reinforced composite body 11 is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION Invention II'i relates to a method for producing a fiber-reinforced composite.

Conventionally, for example, engine connecting rods, etc.17) g(
As the S material, a fiber-reinforced composite made by mixing fibers such as alumina and carbon into the composite material such as aluminum alloy and magnesium alloy will be used to increase strength and make it lighter. 2 is known.

Conventionally, when manufacturing such fiber-reinforced composites, the method used was to fill a mold with fibers, increase the packing density through compression, and then pour matrix metal and perform pressure casting. Generally adopted.

However, in the above conventional manufacturing method, when the fiber is compressed, EV > so-called spring looseness, therefore,
It was difficult to increase the packing density of the fibers to the set value, and as a result, there was a problem that the strength of the 11t-stranded composite was insufficient. Therefore, fibers are mixed with wax to form a mixture of the two, the mixture is filled into a mold of a predetermined shape, and pressed to form a mixture molded body having a predetermined fiber acousticity. After forming a refractory layer by laminating several coating layers and sanding layers alternately on the outer periphery of the mixture molded body, the mixture molded body with the refractory layer formed thereon is heated to remove the wax in the mixture molded body. When necessary, the refractory layer is fired to form a mold in which the cavity is filled with TC fibers, and then matrix gold 44 is poured into the mold to remove the fibers. By integrally coagulating the fibers, the so-called springback during pressurization of the fibers can be reduced as much as possible by mixing with the wax and the packing density of the fibers can be increased. A method for manufacturing a fiber-reinforced composite has been proposed in which it is possible to remanufacture a fiber-reinforced composite having a strength equal to or equal to a set value of J3 depending on L%.

(2) However, when the connecting rod shown in Figure (K) is manufactured by the above method, for example, circle A.

In the portion surrounded by B, that is, in the curved portion where the curvature is small or the portion where the curvature changes sharply into a III-shape, the fibers become frayed due to springback, causing a disadvantage that the shape (shift) occurs.

The object of the present invention is to eliminate the above-mentioned disadvantages and provide a method for using a fiber-reinforced composite that does not lose its shape even when placed in a curved part with a small curvature or in a part where the shape rapidly changes. .

An embodiment of the invention will now be described in Figure I7i'.

First, inorganic long fibers made of alumina as shown in IJ(a) 1.1. ... is cut to form a short edge i12.2. with a length of about 20 m as shown in Figure (b). ... is prepared, and the short fibers are placed in containers 3a and 3b as shown in Figure (0).
into the molten wax 4, one volume 63b has a low fiber mixing ratio with a molten wax concentration of 51 to 55 weight percent, and the other volume 63b has a molten wax concentration of 48 weight percent. Make a high fiber mixture ratio consisting of a mixture ratio of
A mixture of short fibers 2, 2... and molten wax 4 is prepared by keeping at ~100°C.

Then, knead the mixture (s)! As shown in FIG. 3, the mold 5 is filled with a connecting rod-shaped cavity formed by a lower punch 5a, a die 5b, and an upper punch 5C. In this case, the above-mentioned container 3a is placed in the cavity corresponding to the small curve h1ζ or the rapid shape change part in the above figure (the curvature surrounded by circles A and B of the connecting rod shown in illusion, 7).
Fill the mixture with a low fiber mixing specific strength taken out from the container 3b, and fill it into the inner part, approximately the 1l-f line part not surrounded by B, or the part where there is no sudden change in shape. Fill with a mixture having a high fiber mixing ratio.

・Subsequently, by pressing the filler in the above-mentioned groove, a connecting rod-shaped mixture molded body 6' + - is formed as shown in Δ(f). At that time, the above mixture molded body 6 Since the wax 4 is in a sticky state on the surface of the short fibers 2.2°, the adhesive force of the wax 4 causes the short fibers 2.2° to be compressed by the press.
2. ... T If so-called springback occurs, it is prevented, and therefore the fiber packing density of the mixture molding experience can be set to a predetermined value, and the short fibers 2, 2, . ... to compress the short fiber 2.
2. ... can be uniformly filled into every corner of the mixture molded body 6, and curved parts with small curvatures and parts with rapid shape changes can be molded with a mixture with a low fiber mixing ratio, so that shape deformation can be prevented. 1- Obtain a predetermined shape by properly preventing.

After that, as shown in 1Δ(g), the mixture molded body 6
Add a hot water lower made of wax, a riser 8, etc. to 7[itL].

After repeating the operation of immersing the 171 integral body in the slurry and sprinkling it with refractory sand several times, it is dried, and as shown in Figure 1 (h), the coating # (slurry) and the sanding layer ( refractory sand) several layers alternately
A refractory layer 9 is formed.

Next, the mixture molded body 6 with the refractory layer 9 formed thereon is dewaxed at a dewaxing temperature v IILI yI! of 500 to 1000°C, as shown in FIG. After eluting the four wax components in the mixture forming process 6, the refractory layer 9 is fired at a high temperature. : )) The mold 10 is formed by filling the fibers in the gap.

Thereafter, the matrix metal made of aluminum alloy in this mold 10 is solidified integrally with the fibers by pouring I-, and the mold 10 is removed to form a fiber-reinforced connecting rod as shown in Figure (k). A composite 11 is produced I4.

The fiber-reinforced composite 11 thus obtained is one in which the wax 4 is replaced with a matrix metal in the mixture molded body 6T described above, and the matrix gold, 1
Since the fibers are mixed in the upper layer at a high filling degree, various mechanical strengths are improved.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but also includes various modifications.For example, magnesium alloy may be used as the matrix metal, glass, carbon, silicon may be used as the fiber The present invention can also be applied to the case where a composite body constituting a piston pin or the like is manufactured using inorganic fibers such as carbide, or metallic fibers such as 2 ungsten or stainless copper.

In the above embodiment, the dewaxing process of the mixture molded body 6 and the firing process of the refractory were separated, but when using fibers that have extremely low deterioration at high temperatures, both processes can be performed by performing high-temperature heating. On the other hand, when using fibers that are easily oxidized and deteriorated at high temperatures, such as the above-mentioned carbon fibers, the firing step of the refractory may be omitted.

In the table below, test pieces were made with mixtures of different wax concentrations that were press-molded (load: 700 odor/d) to an outer diameter of 27 mm, an inner diameter of 18 mm, and a height of 24 mm, and the shapes of these test pieces were The results of testing the degree of deviation are shown. (However, in the table below, the ○ mark indicates that the shape has not been deformed, and the Mono-association of mixtures with low ratios does not result in the form guzu-shichi.

As explained above, this invention involves preparing a mixture of fibers and wax with different mixing ratios (two types), and making a kneaded mixture t.
The mixture with a low fiber mixing ratio is filled in the curved part with a small curvature or the part where the shape changes rapidly, and the mixture with a high fiber mixing ratio is filled in the approximately straight part or the part where there is no sudden shape change. The entire fiber-reinforced composite is formed.
Since i7Lτ exists, it is possible to provide a fiber-reinforced composite having an appropriate shape that does not shift as a whole.

[Brief explanation of drawings]

The drawings are manufacturing process diagrams illustrating embodiment Ia of the present invention. 2... Short fiber, 4... Molten wax, 5... Mold, 6... Mixture molded body, 9... Refractory layer, 10...
- Mold, 11... fiber reinforced composite. Patent applicant: Toyo Kogyo Co., Ltd. (a)
(b) 2 (h) (i) 'k. (f) (9') (j) (k)

Claims (1)

[Claims] (1) Mix inorganic short fibers or metal short fibers with molten wax to make a mixture of short fibers and wax, fill the mixture into a mold with a cavity of a predetermined shape, and then press A mixture molded body having a predetermined fiber density is molded 1-1, and several coating layers and sanding layers are alternately laminated around the outer periphery of the mixture molded body to form a refractory layer 'fr. The wax in the mixture molded body is heated to dissolve the wax in the mixture molded body, and if necessary, the refractory layer is fired, and the mold with the cavity filled with VC fibers is formed by the refractory layer. In the case of forming a fiber-reinforced composite by pouring the matrix metal into the vaginal mold and coagulating it integrally with the fibers, the above-mentioned mixture has a different mixing ratio of fibers and wax. At least two types of mixtures are prepared, and among these mixtures, a mixture with a low fiber mixing ratio is filled into a curved part with a small curvature or a sharply changing part of the cavity, and a mixture with a high fiber mixing ratio is filled into a substantially straight part or a sudden shape change part. A method for producing a fiber-reinforced composite, comprising forming the fiber-reinforced composite by filling a portion that does not change shape.