JP2984904B2 - Cutting blade for magnetic tape - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a corrosion-resistant non-magnetic cemented carbide, and more particularly to a corrosion-resistant non-magnetic cemented carbide used for cutting magnetic tape.

[0002]

2. Description of the Related Art Conventionally, cutting blades of carbon steel, high-speed steel, cemented carbide, ceramics and the like have been used for cutting magnetic tapes and the like. Among them, carbon steel and high-speed steel have a large amount of wear on the cutting edge and cannot withstand long-time slitting due to the hardness of the material. Ceramics are inferior to metal cutting blades in terms of material reliability. For these reasons, currently, WC-
Co-based cemented carbides are often used.

[0003] For example, Japanese Patent Application Laid-Open No. 61-12847 (hereinafter referred to as Conventional Example 1) discloses that V,
There has been proposed a cemented carbide having excellent wear resistance and high toughness, which aims to suppress the grain growth of WC by a combined effect by adding Cr.

[0004] Also, Japanese Patent Application Laid-Open No.
Conventional example 2), vanadium carbide and zirconium nitride are added to obtain an HRa of 91 or more and a bending strength of 35.
A cemented carbide having excellent characteristics of 0 kg / mm ² or more has been proposed.

Further, Japanese Patent Publication No. 4-31012 (hereinafter referred to as Conventional Example 3) discloses that Co or Ni
Addition of chromium carbide does not cause micro chipping, thus increasing crack propagation resistance.

[0006]

However, when any of the above-mentioned cemented carbides is used as a cutting blade, there is a tendency to reduce the occurrence of chipping and the like during slitting, but the orientation occurs during the orienteering of magnetic powder, that is, during cutting. It does not contribute to preventing the magnetic powder from being disturbed. Also, no consideration is given to corrosion occurring during the handling of the cutting blade, for example, corrosion during regrinding.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a magnetic tape cutting blade having improved magnetic powder turbulence generated during cutting and corrosion generated during handling of the cutting blade.

[0008]

Means for Solving the Problems The present inventors have studied to solve the above technical problems, and as a result, have found that a magnetic tape which can prevent disturbance of magnetic powder generated at the time of cutting and corrosion generated during handling of a cutting blade can be prevented. Corrosion-resistant non-magnetic cemented carbide used for cutting blades for steel and its manufacturing method.

That is, in the corrosion-resistant non-magnetic cemented carbide of the present invention, chromium carbide is added as a hard phase component in an amount of 0.5 to 2.0.
1.0 to 5.0% by weight of molybdenum carbide, the remainder being mainly composed of tungsten carbide, and 5.0 to 25.0% by weight of nickel as a binder phase component.
It is characterized in that the grain size of carbide in the alloy is 1.0 μm or less.

Here, the reason why the chemical composition of the corrosion-resistant non-magnetic hard metal of the present invention is limited as described above will be described. In the present invention, chromium carbide is added in an amount of 0.5 to
The reason why the amount is limited to 2.0% by weight is that if the amount of addition is less than 0.5% by weight, the desired effect of suppressing the grain growth is not observed, while
When the content exceeds 10% by weight, the toughness of the corrosion-resistant non-magnetic cemented carbide decreases, and the content is limited to 0.5 to 2.0% by weight. In the present invention, molybdenum carbide is added in an amount of 1.0%.
The reason for limiting to 5.0% by weight is that the amount added is 1.0% by weight.
If it is less than 1, the amount of solid solution in the binder phase is small, and the expected effects such as demagnetization and corrosion resistance cannot be obtained. On the other hand, if it exceeds 5.0% by weight, it precipitates as a third phase in the alloy depending on the cooling rate or the like and causes a decrease in toughness. Therefore, its content is limited to 1.0 to 5.0% by weight.

Further, in the present invention, the nickel content is limited to 5.0 to 25.0% by weight because if the nickel content is less than 5.0%, the corrosion-resistant non-magnetic cemented carbide is not sufficiently densified. Not done. On the other hand, if it exceeds 25.0% by weight,
Since the hardness as a cutting blade of a magnetic tape or the like is insufficient and wear resistance is reduced, the content is limited to 5.0 to 25.0% by weight.

Further, in the present invention, the reason why the grain size of carbides in the alloy is set to 1.0 μm or less is that if it exceeds 1.0 μm, the expected corrosion resistance cannot be obtained.

In the present invention, the lattice constant is set to 3.5.
The reason for setting it to 70 to 3.580 angstroms is 3.5
If it is less than 70, the amount of chromium carbide and molybdenum carbide dissolved in the binder phase is small, and the effect of non-magnetic and corrosion resistance is small. On the other hand, if it exceeds 3.580 angstroms, a third phase may be formed in the alloy depending on the conditions, and a price of fracture resistance is caused.

[0014]

Embodiments of the present invention will be described below.

(Example 1) As a raw material powder, an average particle size of 0.1 was used.
8 μm fine WC powder, chromium carbide having an average particle diameter of 1.3 μm, molybdenum carbide having an average particle diameter of 1.5 μm, and nickel having an average particle diameter of 2.0 μm were blended so as to have the composition shown in Table 1 below. The mixture was mixed in an alcohol by wet mixing for 12 hours. After mixing, dried under reduced pressure, 1000 kg / cm
Press molding was performed at a pressure of ² . Then, after vacuum sintering at 1400 ° C. for 1 hour, hot isostatic pressing (HIP) was performed at 1350 ° C., 1000 kg / cm ² for 1 hour in an argon atmosphere.

As a comparative alloy, a fine WC powder having an average particle diameter of 0.8 μm as a raw material powder, an average particle diameter of 1.3 μm
Chromium carbide, molybdenum carbide with an average particle size of 1.5 μm,
Cobalt having an average particle size of 1.0 μm was mixed in alcohol, adjusted and sintered in the same manner as in Samples 1 to 8 above. The sintered bodies according to the example and the comparative example were ground with a diamond grindstone and 4 ×
8 × 25 mm JIS bent pieces were prepared, and these samples were measured for Rockwell hardness (HRa). For the cemented carbide grain size, use a scanning electron microscope (S
(EM) and the average particle size was measured. The results are shown in Table 2 below. The lattice constant of the binder phase was determined by X-ray diffraction after dissolving and removing tungsten carbide present on the surface of the corrosion-resistant cemented carbide.

The results are summarized in Table 2 below.

[0018]

[Table 1]

[0019]

[Table 2]

(Example 2) Of the samples obtained in Example 1, each of the alloys 1, 4, and 7 of the present invention and the comparative alloys 10, 14, and 17 was used as a corrosion test piece.

In the corrosion test, hydrochloric acid (HCl), nitric acid (HN)
After immersion in a 10% solution of O ₃ ) at a liquid temperature of 25 ° C. for 24 hours, the corrosion loss was measured and the amount of corrosion per unit time was determined. The results were shown in Table 3 below.

[0022]

[Table 3] As is clear from Table 3, the alloy of the present invention has a lower corrosion rate than the comparative alloy and is excellent in corrosion resistance.

(Example 3) The corrosion-resistant non-magnetic cemented carbide 4 according to the present invention shown in Table 1 and the cemented carbide 1 according to the comparative example
Using No. 4, a cutting blade was prototyped, and a magnetic tape (normal tape) was slit under the conditions shown in Table 4 below.

FIG. 1 is a perspective view showing a cut surface 3 of a magnetic tape 1 cut with a corrosion-resistant non-magnetic cemented carbide according to the present invention, and FIG. 2 is a perspective view showing a cut surface 7 of a magnetic tape 5 cut with a comparative alloy. . As shown in FIG. 1, the magnetic tape 1 cut with the corrosion-resistant non-magnetic cemented carbide of the present invention was excellent in that the magnetic powder 2 was not disturbed on the cut surface as compared with the magnetic tape 5 cut with the comparative alloy. Was. Further, in the magnetic tape 1 cut with the alloy of the present invention, the cutting dust of the magnetic powder generated at the time of cutting could be sucked without falling down on the tape surface. However, in the magnetic tape 5 cut with the comparative alloy, as shown in FIG. 2, the cutting waste 6 of the magnetic powder 2 was scattered on the tape surface.

[0025]

[Table 4]

From the above, the corrosion-resistant non-magnetic cemented carbide according to the embodiment of the present invention is more effective than the cemented carbide according to the comparative example.
It was found that both corrosion resistance and non-magnetic properties were good.

[0027]

According to the present invention as described above,
It is possible to provide a magnetic tape cutting blade and a corrosion-resistant nonmagnetic cemented carbide used for the magnetic tape, which are improved in disturbance of magnetic powder generated during cutting and corrosion generated during handling of the cutting blade.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a cross section and a surface of a tape cut by a magnetic tape cutting blade according to an embodiment of the present invention.

FIG. 2 is a perspective view showing a cross section and a surface of a tape cut by a magnetic tape cutting blade according to a comparative example.

[Explanation of symbols]

 1,5 Magnetic tape 2 Magnetic powder 3,7 Cutting surface 6 Cutting waste

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-318380 (JP, A) JP-A-2-190439 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B26D 1/00

Claims (2)

(57) [Claims] 1. A cutting blade of the upper and lower A cutting blade facing vertically is use for cutting the magnetic tape, Ri Do from corrosion nonmagnetic cemented carbide, the corrosion resistance nonmagnetic cemented carbide, hard
0.5 to 2.0% by weight of chromium carbide
Containing 1.0 to 5.0% by weight of molybdenum bromide,
Tungsten carbide as the main component and binder phase component as
Of nickel in the alloy by 5.0 to 25.0% by weight.
A cutting blade for a magnetic tape , wherein the particle size of the compound is 1.0 μm or less . 2. The cutting blade for a magnetic tape according to claim 1 , wherein the corrosion-resistant non-magnetic cemented carbide has a lattice constant of 3.5.
A cutting blade for magnetic tape, comprising a binder phase of 70 to 3.580 Angstroms.