JPH0633182A - Wear resistant sintered compact and its production - Google Patents

Abstract

PURPOSE:To produce a homogeneous wear resistant composite sintered compact by forming each chip, composed of a sintered compact of sintered hard alloy, into a polygonal shape having recessed parts at respective edges, spreading these chips all over a base material, and integrating them by casting a molten metal. CONSTITUTION:A chip having a polygonal shape where recessed parts are provided on respective edges is prepared by using a sintered compact of sintered hard alloy. These chips are spread all over a base material, and then, a molten metal is poured and cast in, by which these are integrated. By this casting, a wear resistant sintered compact for which super hard chips are used as hard phase and a casting is used as binding phase is prepared. At this time, the interface between the super hard chips and the binding phase has superior adhesion via the recessed parts, and further, the super hard chips are free from moving at the time of casting because they are spread as mentioned above, by which the composite body having homogeneous and stable properties can be obtained.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a composite sintered material suitable for wear resistant tools.

[0002]

2. Description of the Related Art Cemented carbide obtained by combining WC particles with Co or the like is used for various industrial applications because it has high hardness and high wear resistance. However, when it is applied to mechanical parts that are subjected to tensile stress or shock load, it cannot be used alone due to its brittleness, and it is essential to combine it with other tough metal materials. is there.

However, in order to sinter-composite WC particles in a material having a relatively high toughness, conditions such as the melting point of the base material, the specific gravity and the wettability with the cemented carbide particles are required. For example, Japanese Patent Application Laid-Open No. 57-171563 discloses an example in which hard particles such as WC and TiC are sintered and bonded with Ni wax, and Japanese Patent Application Laid-Open No. 61-87846 discloses an example in which they are bonded with steel. However, vacuum sintering and HIP
And the above conditions are satisfied. In addition, a wear-resistant tool in which a W ₂ C-WC eutectic as a surface-hardening alloy is filled in a mild steel pipe and built up by welding is put into practical use.

Further, in the case of producing a composite material in which a cemented carbide is dispersed in a metal, a method of casting with molten metal has been invented (Japanese Patent Publication No. 3-13942), but according to this method, In order to fix bits made of cemented carbide, bits etc. are implanted in advance and cast metal is used to make a stuffed product to strengthen it. Further, JP-A-2-187250 discloses an example in which a polyhedron is used for a chip.

[0005]

In order to solve the above problems, the present invention is a composite sintered body using a cemented carbide tip as a hard phase and a casting as a bonding metal, and its purpose is as described above. In order to cope with various problems, a casting that is a molten metal, a hard phase such as a cemented carbide tip, that is, WC, and C
The shape of a chip of a sintered body composed of a binder phase such as o was studied and improved so as not to move during casting and to have a non-uniform dispersion degree.

[0006]

Therefore, in the present invention, the cemented carbide tip is formed in the shape of a polygonal plate in advance, and recesses are provided on each side thereof. The chips are spread on the base metal by each side, and the casting enters the voids formed by the recesses and comes into close contact with the base metal. By using this tip, the cemented carbide tip does not move during casting, and the performance is stable because it is spread evenly.

[0007]

First, the raw material used for the wear resistant sintered body of the present invention may be a cemented carbide sintered chip, and the material thereof is not particularly limited. Further, when the thickness is required, the life can be adjusted by increasing the chip thickness or using a higher hardness cemented carbide. Further, if the application is such that the wear locally progresses, it is possible to use different materials for the cemented carbide chips in the method of the present invention in which the cemented carbide chips are spread. Further, in applications in which wear progresses as a whole, it is possible to disperse cemented carbide particles in a casting and harden the casting itself.

[0008] Next, regarding the shape, an appropriate choice is made depending on its application, the area of the composite portion, and the condition of wear. Particularly, a large tip has a large inscribed circle, and a long edge such as an impeller blade has a small inscribed circle. The same size is used for those that require overall wear resistance, such as impeller blades, but in applications where mechanical rubbing wear is the main, large and small sizes are used in combination.

Further, as for the size of the concave portion provided on each side, a relatively small area is sufficient because the cast steel and the structural steel, which is the base metal, have good adhesion, but the minimum size is required when rubbing wear occurs. It is necessary to supplement the wear resistance of the cast part.

[0010]

EXAMPLES The present invention will be specifically described below with reference to examples. As a cemented carbide chip, 6% Co alloy (density ρ = 14.9 g / cc) and a mixed powder having a particle diameter of 2.5 microns were press-molded into a shape as shown in FIG. 1, and after sintering,
It was spread on the base metal and the molten metal was poured. As described above, the wear-resistant sintered body was obtained as shown in FIG.
The wear-resistant sintered body thus obtained can be applied as a wear-resistant member such as a wear-resistant portion of a construction machine or a machine part requiring higher wear resistance, as in the case of the surface-hardened alloy.

[0011]

As described above, according to the method of the present invention,
Using hard cemented carbide chips and tough castings as the binder phase,
After the cemented carbide tips are dispersed, the molten metal is poured into the casting to make it look like a solid body, so the adhesion at the interface between the cemented carbide tips and the binder phase is excellent, and because the cemented carbide tips are spread out, the dispersion does not deteriorate due to casting. Performance is stable. In addition, since it is spread, the material of the cemented carbide tip can be locally changed depending on the purpose of use, and it can be applied according to the application.

[Brief description of drawings]

FIG. 1 is an explanatory view of a cemented carbide tip.

FIG. 2 is an explanatory view showing a state where the cemented carbide tip of FIG. 1 is laid on a base metal and cast.

FIG. 3 is a sectional view of a main part of FIG.

[Simple explanation of symbols]

 1 Carbide chip 2 Base metal 3 Casting

Claims (2)

[Claims] 1. A wear-resistant sintered body obtained by integrally molding cemented carbide particles as a hard phase in a casting by casting, wherein the cemented carbide particles have a polygonal shape, and concave portions are provided on the sides. Characteristic wear resistant sintered body. 2. A wear-resistant sintered body using a cemented carbide chip as a hard phase and a casting as a binder phase, which is a polygonal chip in which recesses are provided on each side of a cemented carbide alloy sintered body. A method for producing a wear-resistant sintered body, characterized in that chips are spread on a substrate, and then molten metal is poured into the cemented carbide / casting / substrate-casting composite to form a single integrated body.