JPS5923834A - Fiber reinforced alloy - Google Patents

Abstract

PURPOSE:To provide a fiber reinforced alloy having the excellent heat resistance that makes the alloy adaptable to mechanical parts used in a high temp. range, by constituting the same of reinforcing fibers consisting of fibers having ultrahigh heat resistance and high tensile strength and a metallic matrix. CONSTITUTION:Annular groove parts 3 are formed in the band parts 2 at both ends of the casting mold 1 of a centrifugal casting machine, and reinforcing fibers 4 are fitted and supported in the groove parts 3; further, prescribed spaces from the inside surface of the mold 1 are formed of plural pieces of spacers 5 which are metallic rings. The fibers 4 are constituted by braiding fibers having excellent heat resistance and tensile strength such as three-element fibers of alumina, boron oxide and silica consisting of, for example, about 63wt% Al2O3, about 14% B2O3 and about 24% SiO2. Molten metal 7 of 25Cr-20Ni alloy or the like is charged into such mold 1, and the mold 1 is rotated to cast centrifugally the molten metal, whereby a part 8 which has the fiber reinforced alloy A in the surface layer part and is suited for the conveyance roll or the like in a heat treatment furnace of a high temp. is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fiber-reinforced alloy with excellent heat resistance that is mainly used as a mechanical structural material.

Conventionally, various fiber reinforced alloys (FRM) consisting of a metal matrix and reinforcing fibers have been proposed.

These fiber-reinforced alloys include carbon, silicon carbide, boron,
It is a composite phase of reinforcing fibers made of alumina or the like and metal matrix materials such as aluminum or titanium, and its heat resistance and heat insulation properties are not very high. Therefore, it could not be particularly applied to parts (members) that are exposed to high temperatures, such as in-furnace conveyor rolls of heat treatment furnaces.

The present invention is based on the invention that fiber materials commonly used as furnace entrance/exit curtains, thermocouple protection materials, and furnace internal parts linings have a heat resistance of 1400'C or higher and have high tensile strength. The present invention was developed with this in mind, and aims to provide a fiber-reinforced alloy that can be used as furnace parts by using the above-mentioned super heat-resistant, high-strength fibers as reinforcing fibers.

Next, the present invention will be explained according to the drawings which are examples.

The drawings show a case in which a reinforcing fiber alloy layer is formed on the roll surface layer during centrifugal casting of the roll using a centrifugal casting machine to obtain a fiber-reinforced roll.

In FIG. 1, 1 is a mold of a known centrifugal casting machine, 2 is a band portion that closes both ends of the mold 1, and reinforcing fibers 4 are formed on the inner surface of the hand portion 2 with a predetermined gap from the inner surface of the mold 1.
A ring-shaped groove 3 is provided to hold the holder. Further, on the inner surface of the mold 1, a plurality of metal rings as spacers 5 are arranged at predetermined intervals.

Examples include alumina, boron oxide, and silica (J203: 62°B2O), which have excellent heat resistance and tensile strength.
A reinforcing fiber 4 made of pipe-shaped 3-element fibers of 3:14, 5102:24wet% was inserted into the ring-shaped groove 3.
25Cr-2ONi metal solution i% (C: 0.41, Si: 1.18.Mn
: 1.02°P: 0.015. S: 0.011, C
r:24.41. Ni: 20.28°Mo: Q, Q5
WeL%) is injected from the injection port 6 and the mold 1 is rotated to centrifugally cast the roller 8.

In the centrifugal mold roller 8 obtained in this way, as shown in FIG. By pressure injection, a roll made of fiber-reinforced alloy A having reinforcing fibers 4 in the surface layer is obtained. Then, by cutting and removing the metal layer 7a on the surface, a centrifugal casting roll having the desired fiber-reinforced alloy on the roll surface layer is obtained.

Note that when reinforcing fibers are laminated, sufficient pressurized injection of the molten metal may not be achieved, so instead of the ring-shaped spacer 5, a layer of iron with a lattice constant within ±15% of the Fe lattice constant is placed on the inner surface of the mold 1 in advance. Alternatively, a molten metal such as a low melting point metal such as Al or Zn may be poured into a mold, solidified by casting, and reinforcing fibers may be attached inside the mold. In this case, the solidified material of Ad, Zn, etc. is melted during centrifugal casting by the heat of the molten metal subsequently injected, and becomes a solid solution that diffuses with the molten metal.

In addition, in cases where the reinforcing fibers 4 have two or more layers, or the reinforcing fiber layer thickness is relatively large, and it is difficult to pressurize injection of molten metal even in the casting solidification method of the above-mentioned AI, Zn, etc., pipe-shaped reinforcement may be used. At least one through hole is provided on the pouring side of the fiber, and the reinforcing fiber is installed with a predetermined gap from the inner surface of the mold,
The molten metal may be press-fitted into the reinforcing fibers from the inside and outside of the pipe-shaped reinforcing fibers.

In addition, aromatic holamide fibers may be used as the reinforcing fibers.

The roll made of 25Cr-2QNi and 25Cr
A comparison of the thermal conductivities of rolls made of fiber-reinforced alloys of -2QNi and alumina/boron oxide/silica fibers revealed that the former was 0.052C,al/(
J-5eC,'C Tearnoni vs. the latter Teha, 0.00
8 ca (J/cm-sec, .C, approximately 1/6.
It was found that the thermal conductivity was 5 times higher, and its insulation effect was extremely good.

It goes without saying that the fiber-reinforced alloy according to the present invention can be manufactured not only by centrifugal casting but also by other methods.

As is clear from the above explanation, according to the present invention, super heat-resistant and high tensile strength fibers such as three-element fibers of alumina, boron oxide, and silica are used as the reinforcing fibers of the fiber-reinforced alloy. It can be applied to mechanical parts, etc. used in a constant high temperature range.

2 is a schematic half sectional view of a casting machine, and FIG. 2 is a partial sectional view of a roll cast by the centrifugal casting machine of FIG. 1.

DESCRIPTION OF SYMBOLS 1... Mold, 2... Band part, 3... Ring-shaped groove, 4... Reinforced fiber, 5... Spacer, 8... Roller.

Figure 1 Figure 2

Claims (1)

[Claims] ('') A fiber-reinforced alloy characterized in that the reinforcing fibers are ultra-heat resistant and high tensile strength fibers. (1) The fiber-reinforced alloy according to claim 1, wherein the reinforcing fibers are ternary fibers of alumina, boron oxide, and silica.