JPH04198453A - Hard alloy - Google Patents

Abstract

PURPOSE:To obtain a sintered hard alloy excellent in wear resistance, hardness, and machinability by constituting this alloy of a hard phase consisting of carbides, etc., of group IVa, Va, and VIa metal elements and having specific grain size and a specific amount of binding phase consisting of iron group metals. CONSTITUTION:In a hard alloy which consists of a hard phase consisting of the carbide, nitride, and carbonitride of group IVa, Va, and VIa metal elements of the periodic table of elements and having <=1mu grain size and a binding phase consisting of one or more kinds among iron group metals, the content of the above binding phase is regulated to <=2% by weight. The above hard alloy can be obtained, e.g. by mixing the powder of the above hard phase and the powder of the binding phase at the prescribed proportion by means of a ball mill, compacting the resulting powder mixture, performing presintering at about 1300-1600 deg.C, and further exerting sintering by means of hot isostatic pressing. In this hard alloy, the existence rate of the binding phase metal in the hard alloy is regulated to 0.2-2% and magnetization characteristics are provided, and further, Vickers hardness and deflectivity are regulated to >=1800kg/mm<2> and >=80kg/mm<2>, respectively. By this method, the hard alloy excellent in wear resistance, hardness, and machinability as tool alloy can be obtained.

Description

[Detailed Description of the Invention] <Industrial Field of Application> The present invention is directed to the use of cemented carbide, cermet, It relates to hard alloys such as ceramics.

<Conventional technology and its problems> Conventionally, hard alloys for tools that have good wear resistance and excellent cutting properties are carbides of group IVa, Va, and VIa metal elements,
It is well known that it is obtained from a hard phase made of nitride or the like and a binder phase of iron group metal.

However, the amount of iron group metal used as a binder phase in hard alloys to date is mostly 2 to 20% by weight. It has been recognized that if the amount is less than 2% by weight, the resulting hard alloy has no practical properties such as impact resistance and toughness.

Furthermore, it was recognized that if it exceeds 20% by weight, the high-temperature hardness decreases, which is undesirable.

Furthermore, as in the present invention, grain size 1 made of carbides, nitrides, and carbonitrides of IVa, Va, and VIa group metal elements.
(Hard alloys that use a hard phase of less than It was not desirable as a hardness alloy for tools.

<Means for Solving the Problems> In view of the above, the present invention aims to obtain a hard alloy with excellent frictional wear resistance, cutting wear resistance, etc. by reducing the amount of iron group metal in the binder phase to 2% by weight or less. This is the result obtained.

That is, the present invention applies to group IVa, group Va, and V of the periodic table of elements.
Consisting of a hard phase with a grain size of 1μ or less consisting of carbides, nitrides, and carbonitrides of group Ia metal elements and a binder phase of one or more iron group metals, the binder phase content being 2% by weight or less. It is an object of the present invention to provide a hard alloy characterized by certain characteristics.

<Function> As described above, the present invention uses as a hard phase one or more carbides, nitrides, and carbonitrides of metal elements of Groups IVa, Va, and VIa of the Periodic Table of Elements and having a particle size of 1 μm or less. The sinterability during production of a hard alloy is improved by using a ferrous alloy and the amount of a binder phase made of an iron group metal is 2% by weight or less, and the abundance ratio of the binder metal in the resulting hard alloy is improved. It is a hard alloy having a magnetization characteristic of 0.2 to 2%, and is characterized by being hard and easy to process.

An example of the method for manufacturing the hard alloy of this invention will be explained as follows.
Raw material powder with a particle size of 1 μ or less constituting a hard phase consisting of one or more of carbides, nitrides, and carbonitrides of metal elements of Groups IVa, Va, and VIa of the Periodic Table of the Elements, and 2% by weight as a binder phase. After wet mixing the following iron group metal powders, molding this mixture, and pre-sintering at 1300 to 1600°C,
Furthermore, at a temperature lower than the liquid phase appearance temperature or higher, 50 kg
It is obtained by hot isostatic press sintering in a high pressure inert gas atmosphere of /cm2 or higher.

In order to obtain a good hard alloy in this invention, the particle size of the hard phase material powder is also a major factor, and the particle size is suitably 1 μm or less.

This is because the hardness of the obtained hard alloy is insufficient if it is 1μ or more, and the finer the particle size, the more uniform dispersion becomes possible and the toughness is improved.

Further, as the hard phase material, one or more powders of carbides, nitrides, and carbonitrides of metal elements of IVa group, Va group, and VIa group are used, but it is preferable that the powder is previously subjected to solid solution treatment.

This invention uses a mixed powder obtained by wet-mixing raw material powders for a hard phase and a binder phase in a ball mill, pre-sintering the powder, and then sintering it in a hot isostatic press. It is preferable to perform the sintering continuously under the same conditions in the same furnace as the preliminary sintering because the pressure during press sintering can be lowered.

Pre-sintering conditions are 1300-1600℃ in a vacuum atmosphere.
X Ihr is suitable, and sintering by hot isostatic pressing is suitably carried out at 1300 to 1600° C. for 1 hr under a pressure of 80 kg/cm 2 or higher in an inert gas atmosphere such as argon.

<Example> Hereinafter, this invention will be explained in detail with reference to Examples.

Raw material powders were prepared by mixing each of the three compositions shown in Table 1 in a wet ball mill for 8 hours.

Using each of these raw material powders at 1400℃ under vacuum
Pre-sintering was carried out for 1 hour, and then in the same furnace under an argon gas atmosphere at a pressure of 80 kg/cm2 at 1400℃ for 1 hour.
Continuously sintered by hot isostatic pressing for hours,
A hard alloy was obtained.

The hardness, transverse rupture strength, cutting wear resistance, saturation magnetism, etc. of the obtained hard alloy were measured, and the results shown in Table 2 were obtained.

Furthermore, the life index of the high-pressure water nozzle made of this hard alloy is also shown in Table 2.

The life index of a high-pressure water nozzle is expressed as the usage time until the nozzle diameter reaches twice the initial nozzle diameter.

Further, the cutting wear resistance index was expressed as the time when the flank wear reached 0.3 mm.

Table 1 Table 2 <Effects of the Invention> As explained above, the hard alloy of the present invention has a small amount of iron group metal as a binder phase of 2% by weight or less, but is suitable for use in high-pressure water nozzles, cutting, and sliding. It has been recognized that this alloy has excellent wear resistance, hardness, and cutting properties as an alloy for tools such as dynamic and wire drawing dies.

Claims (3)

[Claims] (1) A hard phase with a grain size of 1μ or less consisting of carbides, nitrides, and carbonitrides of metal elements of Groups IVa, Va, and VIa of the Periodic Table of Elements, and one or more binder phases of iron group metals. A hard alloy characterized in that the content of the binder phase is 2% by weight or less. (2) The abundance ratio of the binder phase metal in the obtained hard alloy is 0.
Claim (
1) The hard alloy described. (3) The hard alloy obtained has a Vickers hardness of 1800 kg.
2. The hard alloy according to claim 1, wherein the hard alloy has a transverse rupture strength of 80 kg/mm^2 or more.