JPS6138245B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an apparatus for producing short fibers mixed with concrete and monolithic refractories (hereinafter referred to as concrete, etc.) for use in reinforcing concrete and monolithic refractories. Conventionally, in fiber reinforced concrete, the reinforcement material is, for example, 0.3 to 0.5 mm in diameter and 20 to 50 mm in length.
mm steel fibers are mixed in and uniformly dispersed in concrete, etc. It is known that the tensile strength and bending strength of concrete, etc. reinforced with such steel fibers increase as the amount of fibers mixed in increases and as the adhesive strength between the fibers and the matrix of concrete, etc. increases. . It is also known that the reinforcing effect can be increased by orienting the fibers in the direction of the tensile force applied to fiber-reinforced concrete or the like. However, if the amount of fibers mixed into concrete, etc. is increased, the fibers will become entangled with each other and fiber balls will occur when mixed with a concrete mixer, etc., so in practice, mixing more than 3% by volume is prohibited. There is. Furthermore, reinforcing fibers that have been commonly used in the past have a linear shape that has approximately the same diameter or cross-sectional area over the entire length, and therefore the adhesive strength between the fiber and the matrix is not large. Recently, in order to increase the adhesion between the fiber and the matrix, European Patent Application No. 32,482 discloses a dogbone-shaped fiber having enlarged ends at both ends of the elongated fiber. However, in the fiber manufacturing apparatus described in this European patent application, the protrusion on the rotary disk has a narrow outer peripheral edge and a tapered cross-sectional shape that tapers toward the narrow outer peripheral edge. As a prerequisite, wide front and rear ends are provided by obliquely cutting the front and rear ends of this protrusion.
Therefore, the surfaces of the front and rear wide end portions and the surface of the narrow middle portion of the protrusion are not located on the same circumferential surface.
Further, the surface of the front wide end portion which is sloped by the beveled cut surface is necessarily formed with substantially the same slope as the surface of the notch that limits the length of the fiber. In protrusions with such a surface, the dogbone-like fibers formed when introduced into the surface of the molten metal pool have different sizes at the front and rear wide ends, and are irregular in size and unstable in shape. ,
The thickness is also uneven, and the dimensions are not consistent. As a result, it is difficult to obtain dogbone-shaped fibers with optimal shape and dimensions to obtain the desired reinforcing effect, and the number of fibers per unit weight is not constant, so when placed in concrete, There is a problem that the desired reinforcing effect cannot be obtained. SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned problems and to provide an apparatus capable of producing a dogbone-shaped fiber having an excellent reinforcing effect. To this end, according to the invention, a rotary disk is provided with circumferential ridges on its outer periphery, the circumferential ridges being provided with circumferentially spaced notches corresponding to the length of the fiber to be produced. A fiber manufacturing device that is provided with a protrusion having a length in a circumferential direction, and that directly produces a fiber of a predetermined length from a molten material by bringing molten metal into contact with the surface of the protrusion of a rotating rotating disk and rapidly solidifying it. At least one side surface of the protrusion is removed, leaving the lengthwise end of the protrusion, so that a dogbone-shaped protrusion surface having front and rear wide end portions and a narrow middle portion is provided on the same circumferential surface. It is characterized by According to the present invention, since the protrusion on the disk has the above-described configuration, the front and rear wide end portions and the narrow middle portion of the protrusion surface are located on the same circumferential surface, and further, the wide end portion is located on the same circumferential surface. The front and rear ends of the section are clearly defined by notches. Therefore, it is not only possible to stably manufacture a dogbone-shaped fiber with a constant shape, length, and thickness, but also to produce a dogbone-shaped fiber with an optimal shape and dimensions to obtain the desired reinforcing effect. As a result, the desired reinforcing effect can be reliably obtained. The invention will now be explained with reference to the drawings. FIG. 1 shows a rotating disk 1 according to the present invention, which is made of a metal with good thermal conductivity, such as copper, and is formed into a disk shape with a diameter of 300 mm and a width of 200 mm, and has a mounting hole for a rotating shaft in the center. 2 are provided, and a plurality of cooling water holes 3 are provided at appropriate intervals in the circumferential direction, and are provided through the disk in the width direction. (not shown)
is attached, and the cooling water is configured to circulate and flow into the cooling water holes 3 through a cooling water passage provided inside the end plate. A plurality of protrusions 5 are provided on the outer circumferential surface of the rotating disk 1 and extend parallel to each other in the circumferential direction. A notch or notch 6 is provided, and the protrusion surface located within the same circumferential surface of the protrusion 5' between the notches 6 and the wide portions 7, 7 at both ends and between these wide portions 7, 7 as shown in FIG. It has a dogbone shape with a narrow portion 8 extending to . Protrusion 5'
The dimensions of the dogbone shape protrusion surface are, for example,
The total length is 30 mm, the width of the wide part 7 is 1 mm, the length of the wide part is 4 mm, the width of the narrow part 8 is 0.3 mm, the height of the protrusion 5' is 3 to 6 mm, and the adjacent protrusions 5 are spaced apart in parallel. The interval between them is approximately 5 mm. FIG. 3 shows another modification of the projection 5' having a dogbone-shaped projection surface, and FIG. 4 shows a dogbone-shaped fiber 10 formed using the rotary disk 1 with projections shown in FIG. . FIG. 5 shows that using the rotary disk 1 having the above-mentioned structure, the surface of the outer peripheral protrusion 5' of the rotating disk 1 is soaked in a predetermined liquid by the dipping method described in Japanese Patent Publication No. 51-8821. The metal is solidified on the projection surfaces 7 and 8 of the outer peripheral projection 5' by contacting the surface of the pool 11 of molten material maintained at a surface level and a predetermined temperature, thereby forming a dogbone-shaped fiber 10 having wide portions 9 at both ends. Here is an example. Figure 6 shows how the rotary disk 1 was used to
By the pendant method described in Publication No. 22898, the hanging molten material 12 is brought into contact with the protrusion surfaces 7 and 8 of the outer circumferential protrusion 5' of the rotating disk 1, and the metal is solidified on the protrusion surfaces 7 and 8. An example of forming a fiber 10 having a dogbone shape will be shown. The molten material 12 can be supplied hanging onto the protrusion surfaces 7 and 8 by pressurizing the molten material and spraying it from a nozzle, or by supplying the wire to the outer periphery of a rotary disk and using an arc torch to connect the wire supply end. can be heated and melted and supplied onto the protrusion surface. Example 1 On the outer peripheral surface of a copper rotary disk 1 having a diameter of 300 mm and a width of 200 mm, an outer peripheral projection 5' having dogbone-shaped projection surfaces 7 and 8 as shown in FIG. 2 was formed. The total length l of each protrusion surface is 30 mm, the length H of the wide part 7 at both ends is 4 mm, the width is 0.7 mm, and the width of the narrow part 8 is 0.3 mm.
And so. This rotary disk 1 was rotated at a rotation speed of 170 rpm, and the protrusion surface on the rotary disk was brought into contact with a 0.40% C molten steel pool maintained at a temperature of 1510°C, and the thickness was approximately 0.2 to 0.3 mm. A dogbone-like fiber was manufactured. The size and shape of this dogbone fiber substantially matched the shape of the protrusion surface on the rotating disk. The obtained dog-bone fiber was mixed with 2.0% volume of concrete having the composition shown in Table 1.
Prepare a cylindrical specimen with a diameter of 10 cm and a length of 14 cm, and
After curing in water for a week, a splitting tensile test according to JIS A 1113 was conducted. The test results are shown in Table 2.

【table】

[Table] Expressed as a multiple of .
In Table 2, toughness is indicated by the amount of energy required to break. Comparative Example 1 is for reinforcement without reinforcing fibers, and Comparative Example 2 is for reinforcement without wide parts or bulges at both ends. Shown is one reinforced with fibers. As is clear from Table 2, by using the dogbone fibers according to the present invention, the tensile strength increased by 50% compared to plain concrete and by 7% compared to that reinforced with straight fibers. In addition, the toughness was increased by more than 20 times compared to plain concrete and by more than 50% compared to that reinforced with straight fibers. Example 2 The protrusion surface shape of the rotary disk was different from Example 1, the total length l was 20 mm, and the length H of the wide part 7 was 4 mm.
mm, the width W ₁ was 0.7 mm, and the width W ₂ of the narrow portion 8 was 0.3 mm. A dogbone-like fiber was formed under the same conditions as in Example 1, mixed at 2.0% by volume with concrete having the mixing ratio shown in Table 1, and subjected to a splitting tensile test according to JIS A 1113. The results are shown in Table 3.

[Table] As is clear from Table 3, by using the dogbone fiber according to the present invention, the tensile strength is increased by 55% compared to plain concrete.
It also increased by 10% compared to the one reinforced with straight fibers. In addition, the toughness was increased by more than 25 times compared to plain concrete and by more than 60% compared to that reinforced with straight fibers. Further, since the doghorn fiber according to the present invention has rounded ends, it is difficult to get tangled during mixing, and the occurrence of fiber balls is reduced. In the embodiments described above, as the fiber material
Although 0.40% C steel was used, stainless steel, Al, Cu
etc. can also be used.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of a rotary disk according to the present invention;
Fig. 2 is an enlarged perspective view of a protrusion having a dogbone-shaped protrusion surface on the outer peripheral surface of the rotary disk, Fig. 3 is an enlarged perspective view showing a modification of the protrusion having a dogbone-shaped protrusion surface, and Fig. 4a is a dogbone-shaped protrusion. An enlarged plan view of the fiber, FIG. 4b is a vertical sectional view of the dogbone fiber shown in FIG.
The figure is an explanatory view showing a state in which a fiber is manufactured by a dipping method, and FIG. 6 is an explanatory view showing a state in which a fiber is manufactured by a hanging method. DESCRIPTION OF SYMBOLS 1...Rotating disk, 5...Protrusion, 6...Separation notch or notch, 5'...Protrusion, 7...Protrusion surface wide part, 8...Protrusion surface narrow part, 9...Fiber wide end , 10... fiber, 11...
Molten material pool, 12... hanging molten material.

Claims (1)

[Claims] 1 a protrusion comprising a rotary disk having circumferential ridges on its outer periphery and having a circumferential length corresponding to the length of the fiber to be produced by means of circumferentially spaced notches in said circumferential ridges; In a fiber manufacturing apparatus that directly manufactures a fiber of a predetermined length from a molten material by bringing molten metal into contact with the surface of the protrusion of a rotating rotary disk and rapidly solidifying it, the length direction of the protrusion is At least one side surface of the protrusion is removed, leaving both ends intact;
A manufacturing device for reinforcing fiber for concrete, etc., characterized in that dogbone-shaped projection surfaces having front and rear wide end portions and a narrow middle portion are provided on the same circumferential surface.