JPH0598385A - High capacity cemented carbide alloy - Google Patents

Abstract

(57) [Summary] [Object] The present invention provides a high-performance cemented carbide having a high hardness as well as an excellent wear resistance by limiting the theoretical saturation magnetic content ratio and the coercive force of the alloy to predetermined values. To provide. [Constitution] WC is the main component of the hard phase, and the binder phase is Co1.
It is a high-performance cemented carbide containing 1 to 13% by weight, VC of 0.3 to 0.5% by weight, and Cr of 0.6 to 1.0% by weight. The ratio (δ) is 0.82 to 0.90, and the coercive force (H _c ) is 345 to 345.
It is 420 (O _e ). If a microdrill for drilling a printed circuit board is prepared using a cemented carbide having this magnetic property, breakage and wear of the drill are significantly reduced, and the practical value is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is particularly suitable for use as a material for micro drills for punching printed circuit boards, and also as a material for various cutting tools, mining tools, wear-resistant parts, etc. It concerns hard alloys.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for micro drills for deep holes with a small diameter for precision drilling of printed circuit boards for electronic devices. An alloy having higher hardness and higher toughness than a hard alloy is desired. In other words, a microdrill has a large ratio of length to diameter. For example, a small-diameter drill used with a diameter of 0.05 to 0.5 mmφ drills at a high speed, so there are many loss accidents and a high operating rate of the machine. Abrasion resistance is required.

Therefore, as a conventional example, for example, Japanese Patent Application No. 60
No. 36805, the grain size of WC of the WC-Co alloy is made finer than 0.6 μ, and the raw material WC is
It is described that an alloy having a high hardness and a high transverse rupture strength can be obtained by using a material containing 1.2 wt% Cr and adjusted to a uniform fine particle by a direct carbonization method.

[0004]

By the way, WC-Co
In a cemented carbide system, if the bending strength is increased to increase the toughness, the hardness decreases, while if the hardness is increased to increase wear resistance, the bending strength decreases. Even in the conventional cemented carbide, there is a limit in increasing both the transverse rupture strength and the hardness.

The present invention has been made in order to solve the above-mentioned conventional problems, and by limiting the theoretical ratio of saturation magnetic quantity and coercive force of the alloy to values within a predetermined range, high hardness and transverse rupture strength can be obtained. An object is to provide a high performance cemented carbide.

[0006]

As a result of earnest research, the inventors of the present invention have found that in the magnetic properties of WC--Co cemented carbide, the saturation magnetic content of the alloy (the positive correlation with the alloy C value) is γ phase ( It has been found that it correlates with the W solid solubility of the (bonding phase) and contributes to the wear resistance and heat resistance of the γ phase, but the dispersion of the hard phase, γ phase, and VC phase is the optimum value only with this saturation magnetic amount. On the other hand, it was found that the coercive force (H _c ) of the alloy alone has no direct correlation with the saturation magnetic amount and is independently controlled.

[0007] Further continuing research pays attention to the fact that the saturation magnetic amount of the alloy is inversely proportional to the solid solution amount of W in Co and the coercive force is inversely proportional to the thickness of the Co phase. The inventors have found that the high-performance region of the cemented carbide exists within a certain range, and have completed the present invention.

That is, in the present invention, WC is the main component of the hard phase, Co is 11 to 13% by weight as the binder phase, and V is V.
It contains 0.3 to 0.5% by weight of C and 0.6 to 1.0% by weight of Cr, and the magnetic properties of the alloy have a theoretical ratio of saturation magnetic amount of 0.82 to 0.90 and a coercive force. (H _c ) is 345
It is a high performance cemented carbide with 420 (O _e ).

[0009]

As shown in FIG. 1, the requirement for obtaining the high performance cemented carbide of the present invention is to set the theoretical ratio (δ) of the saturation magnetic amount of the alloy within the range of 0.82 to 0.90 and The magnetic force (H _c ) is in the range of 345 to 420 (O _e ). The saturated magnetic amount increases as the W / Co amount decreases, and when it exceeds 0.90, the F. C (FreeCo
rbon) phase may appear and wear resistance may be deteriorated to cause breakage. If it is less than 0.82, the η phase (intermetallic compound) appears.

As a method for producing the above cemented carbide, 11-
13 wt% Co, 0.3-0.5 wt% VC, 0.6-
Fine powder consisting of 1.0 wt% Cr and the balance WC was mixed, and after press molding, sintered in vacuum at about 1300 to 1450 ° for about 1 hour to give a theoretical saturation magnetic amount of 0.82 to 0. A high-performance cemented carbide having alloy magnetic properties of 0.90 and coercive force of 345 to 420 is obtained.

[0011]

EXAMPLES Hereinafter, examples will be described in detail.

EXAMPLE 1 A predetermined mixture of fine particles W and carbon was used in a carbonization furnace to contain 0.85 wt% Cr ₃ C ₂ .
Create a 5μ WC, and add 0.4% by weight of VC and Co
12.0% by weight, and wet-mixed with a ball mill. After drying and granulating the mixture, 13 × 13 at 1.1 T / cm ²
Press-molded to × 5 mm, and further in vacuum at 1400 ° C for 1
Sintered for a time to obtain a cemented carbide. The results of measuring the magnetic properties of this alloy are shown in FIG. In the figure, those (b) to (e) in the high performance range and those (a), (f), (g), and (h) outside the high performance range are respectively drill diameter φ.
When 0.4 mm × blade length was 5.0 mm and two layers of 4 layers each having a glass epoxy resin substrate of 1.6 mm were punched using this, the results shown in Table 1 were obtained.

[0013]

[Table 1]

From the results shown in Table 1, it can be seen that the samples (b) to (e) in the high-performance region of FIG. 2 have high bending strength and excellent wear resistance.

(Example 2) The raw material fine powder in Example 1 was mixed in an amount of 88.7% by weight WC-0.3% by weight VC-11.
The cemented carbide was obtained through the same manufacturing process as in Example 1 with 0 wt% Co, and the magnetic characteristics shown in FIG. 3 were measured. In the figure, those (b) to (f) in the high performance area and those (a), (g), (h), and (i) in the areas other than the high performance area are perforated under the conditions of Example 1, respectively. As a result, the results shown in Table 2 were obtained.

[0016]

[Table 2]

From the results shown in Tables 1 and 2 above, it was confirmed that the cemented carbides having the magnetic characteristics in the high performance regions shown in FIGS. 2 and 3 had high transverse rupture strength and excellent wear resistance.

[0018]

As described above, according to the present invention, the high-performance region of the cemented carbide has a theoretical alloy saturation magnetic amount ratio of 0.8.
It is in the range of 2 to 0.90 and coercive force of 345 to 490, and by using a cemented carbide having this magnetic property as a material for Druri, it is possible to obtain a tool having high bending resistance and excellent wear resistance. it can.

[Brief description of drawings]

FIG. 1 is a graph showing the high performance range of cemented carbide.

2 is a graph showing magnetic characteristics of the alloy in Example 1. FIG.

FIG. 3 is a graph showing the magnetic characteristics of the alloy in Example 2.

Claims (1)

[Claims] 1. WC as a main component of a hard phase and C as a binder phase
It is a high-performance cemented carbide containing 0.1 to 13% by weight, VC of 0.3 to 0.5% by weight, and Cr of 0.6 to 1.0% by weight. The theoretical ratio is 0.82 to 0.90 and the coercive force (H _c ) is 345 to 345.
420 (O _e ), a high performance cemented carbide.