JP2007143956A - Cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting tool which is rustproof, lightweight than those made of stainless steel or special steel, and has a stronger abrasion-resisting property than carbide dispersion titanium alloy. <P>SOLUTION: A base material includes titanium alloy made of at least either of an alpha phase or beta phase with titanium as the main component and TiB particles dispersed in the titanium alloy. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides a cutting tool having a large blade with a small angle formed on the main surface of the blade and a small blade with a large angle formed along the edge of the main surface. The present invention relates to a blade using a titanium-based composite material in which hard particles are uniformly dispersed in and a manufacturing method thereof, and belongs to a technical field related to knives, cutter blades, cooking blades, scissors, razors, and other various blade materials. It is.

  Pure titanium and titanium alloys are useful materials for various industrial products that are lightweight, have high elasticity, and have characteristics such as sterility and non-magnetism. However, pure titanium and titanium alloys have been considered to be unsuitable as materials for blades that require wear resistance because of their lower hardness than carbon steel, stainless steel, and the like.

  Recently, a composite material in which hard particles are dispersed in the titanium alloy has been developed in order to improve properties such as strength, rigidity, and wear resistance of the titanium alloy. As the dispersed particles, particles such as TiC, TiN, SiC, and TiB2 are used.

  Japanese Patent Application Laid-Open No. 11-131171 reports that a titanium alloy blade to which carbide is added has wear resistance and strength.

Japanese Patent Application Laid-Open No. 8-311586 reports that a blade is obtained by thermally spraying a titanium alloy having TiB on another substrate.
Japanese Patent Laid-Open No. 11-131171 JP-A-8-311586

  However, in Patent Document 1, although it is a titanium alloy blade to which carbide is added, it is known that the wear resistance and strength are insufficient.

  Further, in Patent Document 2, a blade is obtained by thermally spraying a titanium alloy having TiB on another base material. However, when the blade is sharpened, the sprayed titanium alloy having TiB is not immediately worn, so that the product life is short. was there. Furthermore, since the titanium alloy having TiB is sprayed on another base material, there is a possibility that the adhesion is deteriorated and peeled off. Furthermore, the process of thermal spraying a titanium alloy having TiB on another base material has been a heavy burden in production.

  In view of the above problems, the wear-resistant titanium blade of the present invention has a base material in which a titanium alloy containing at least one of α-phase 3 and β-phase 4 whose main component is titanium, and TiB dispersed in the titanium alloy. And particles.

  Part of the TiB particles is exposed on the surface of the titanium alloy.

  The blade material composed of the sintered portion thus obtained can obtain a desired blade by performing a cutting process on a required portion by grinding.

  The wear-resistant titanium blade of the present invention is a wear-resistant titanium blade with improved ductility and toughness and improved properties such as strength from room temperature to high temperature and wear resistance. Naturally, it is lighter than carbon steel, special steel, and stainless steel. Moreover, it is superior to stainless steel blades in terms of sterility even in seawater, and it has higher wear resistance than carbide addition. .

  Further, even in the process in which the blade of the present invention is worn from the beginning, the dispersed TiB particles are always in point contact with the object to be processed, so that the sharpness is not changed.

  In addition, TiB is thermodynamically stable from high temperature to low temperature in the base titanium alloy, hardly dissolves in titanium, and has almost no difference in thermal expansion from titanium, so that TiB particles do not easily fall off. The sharpness will last forever.

  Hereinafter, embodiments of the claimed invention will be described.

  The present invention is characterized in that the base material has a titanium alloy composed of at least one of α phase 3 and β phase 4 containing titanium as a main component, and TiB particles dispersed in the titanium alloy.

  If the TiB particles are not uniformly dispersed and there are places where there are no TiB particles, the wear resistance will be inferior. On the other hand, where there are many TiB particles, densification will not be obtained and voids will occur. It is inferior. It is necessary to mix and disperse TiB particles or precursors to become TiB particles in the raw material preparation stage.

  The reason why it is described as uniform dispersion, not simply dispersion is that TiB particles are isotropic and do not surround α phase 3, β phase 4, α phase 3 + β phase 4, but agglomerate. This is to clarify that they are not. For example, TiB of 20 μm or less is scattered at an average interval of 400 μm or less. Here, as a method for measuring the average distance in dispersibility, an SEM (scanning electron microscope) photograph showing a metal structure (magnification 500 times) is used, and TiB existing at the shortest distance from one arbitrary TiB particle on the photograph. The distance to the particle is defined and the average value is calculated. Due to the uniform dispersion of the TiB particles, it was possible to have higher wear resistance than the carbide addition. This is because, in the case of carbides, it is considered that carbon dissolves in the base material and causes embrittlement, whereas boride does not dissolve in the base material and is a thermodynamically stable element. .

  When the area ratio of the TiB particles is less than 5%, the effect of particle dispersion strengthening is small, and when the material is processed, it becomes a difficult-to-cut material and seizure occurs, and the finished blade is likely to warp. Moreover, when a specific value is exceeded, there exists a possibility that a particle may coarsen and the toughness of an alloy material may fall.

  The titanium alloy as the base material is obtained by adding mechanical alloying elements to pure titanium to improve mechanical properties. The alloying element for strengthening is 0.5% to 7.0% by weight of Al having a Young's modulus greater than β-phase 4 as an α-phase 3 stabilizing element, and β-phase stabilizing element capable of further increasing the strength by heat treatment. 1.0 to 12.0% by weight of V, 2.0 to 30.0% by weight of Mo, 1.0 to 7.0% by weight of Fe, and α phase 3 stable Appropriate mechanical properties such as α-phase 3 + β-phase 4 can be obtained by appropriately adding chemical elements and β-phase stabilizing elements.

  Furthermore, the present invention is characterized in that a part of the TiB particles is exposed on the surface of the titanium alloy.

  Since the TiB particles that have begun to appear at the contact portion of the knife edge of the knife become a pointed contact mechanism with the workpiece, the sharpness does not change. Of course, TiB particles are thermodynamically stable from high temperature to low temperature in the base titanium alloy, are not easily dissolved in titanium, and have almost no difference in thermal expansion from titanium, so TiB particles can easily fall off. Since there is no, the sharpness will continue forever. The protruding amount depends on the aspect ratio of the TiB particles, but it is preferable that the longitudinal direction of the TiB particles protrudes.

  The sharpness is stable up to 128 times by applying an evaluation method in which the cutting edge is applied to the test paper under a constant load, the reciprocating cycle motion of 30 mm one way at a constant speed is reciprocated 128 times, and the number of test paper cuts is recorded per cycle. You can evaluate whether you are doing.

  From the above evaluation method, it can be said that the horizontal axis is logarithmically displayed and the inclination of the sharp straight line up to 128 reciprocations is large, and it has higher wear resistance than others. By performing the test, the base material wears and causes a reduction in sharpness. However, in the process where the base material wears, the dispersed TiB particles appear at any time and the TiB particles come into point contact to form a serrated edge mechanism. There is no change, and the fact that the TiB particles are in the point contact state at the time of blade attachment is also an advantage of the present invention. In particular, it is preferable that the TiB particles have a specific area ratio range protruding from the blade surface. When the area ratio is small, the wear resistance of the serrated blade mechanism is lowered, and when the area ratio is large, the sharpness itself tends to be lowered. Here, the area ratio is measured by using a SEM (scanning electron microscope) photograph (magnification 500 times) showing a metal structure, photographing a 1 mm square from the edge line of the blade edge, in which the particle size of any TiB is The area ratio occupied by TiB of 1 μm or more is obtained.

  The average particle size of the TiB particles is 1 to 20 μm, and among them, particles having an average particle size of 1 to 20 μm are preferably scattered at an average interval of 20 to 400 μm. When the average particle size is less than 1 μm, TiB particles are likely to be shattered, resulting in poor sharpness, and when the average particle size is greater than 20 μm, the quality of the cut surface tends to be rough. And when TiB particles having an average particle diameter of 1 to 20 μm are dispersed at intervals of less than 20 μm on average, there is a problem that the sharpness itself is lowered, and TiB particles having a particle diameter of 1 to 20 μm are at intervals greater than the average of 400 μm. If dispersed, there is a problem that the wear resistance function of the serrated blade mechanism is lowered.

  In addition, it is also possible to add 0.1 to 10% by weight of Ag as a subsidiary component to the blade material of the present invention. If Ag is mixed, the blade made of this blade material has antibacterial properties. And since the compounding quantity is a small amount, it is not lost that it is an advantage of this invention that a bad influence is not exerted on the weight of a blade, a profitability, and the life of sharpness.

  Next, examples of the present invention will be described.

The sample of the present invention contains about 80% titanium, and powder materials of other metals and their compounds are added and mixed, and then a pressure of 4 ton / cm ² is used for compression molding. Sintering is performed in a vacuum furnace at 1,200 to 1,300 ° C. for a required time of about 2 hours.

  The blade material composed of the sintered portion thus obtained can obtain a desired blade by performing a cutting process on a required portion by grinding.

Table 1 shows the results of examining the wear resistance and bending strength by variously changing the amount of TiB dispersed, and FIG. 2 shows a graph of the wear resistance.

  The wear resistance measurement method is based on the above evaluation method. Wear resistance is indicated by ◎ for those with excellent slope, ○ for slightly superior, and for wear resistance. A triangle mark is given to those where no wear resistance is seen.

  As a method for measuring the bending strength, a specimen of 4 mm × 3 mm × 36 mm was used according to the JIS R1601-1995 standard. Those with a bending strength of 1600 MPa or more are marked with ◯, those with 1200 to less than 1600 MPa are marked with Δ, and those with less than 1200 MPa are marked with x.

  Examples 1-5 and Comparative Examples 1-3 are compared.

  In Comparative Example 1, since the TiB particles are not uniformly dispersed, the wear resistance and wear resistance are poor.

  It can be seen that the conventional carbide addition and zirconia ceramics in Comparative Example 2 and Comparative Example 3 are inferior in either wear resistance or bending strength.

Next, Table 2 shows the results of examining initial sharpness, wear resistance, bending strength, and cross-sectional quality by variously changing the α phase: β phase ratio, average particle diameter, and average interval in the titanium alloy.

  In the initial sharpness measurement method, a circle mark is given to those having a first sharpness of 50 or more, and a triangle mark is given to those inferior to that, according to the abrasion resistance evaluation method.

  The method for measuring the cross-sectional quality is a method in which the blade width of the blade edge cross section is examined from a SEM (scanning electron microscope) photograph (magnification 500 times). Those with a blade width of less than 1 μm are marked with ◎, those with a blade width of less than 1 to 3 μm are marked with ◯, and those with a blade width of 3 μm or more are marked with Δ.

  From Sample Nos. 17 to 21, it can be seen that the average particle diameter of TiB is preferably 1 to 20 μm in terms of wear resistance, bending strength and cross-sectional quality.

  From Sample Nos. 22 to 26, it is understood that the average interval of TiB is preferably 20 to 400 μm in terms of wear resistance, bending strength, and cross-sectional quality. In particular, when viewed from the cross-sectional quality, the average particle diameter and the average interval influence the TiB particles, and the existence probability that the TiB particles follow the cutting edge becomes high, so that TiB protrudes too much.

It is a see-through | perspective schematic diagram of the jagged blade condition of the cutter which concerns on this invention. It is a graph which graphed abrasion resistance concerning the present invention. The perspective schematic diagram containing the alpha phase, beta phase, and TiB of the present invention.

Explanation of symbols

1 Test paper 2 Blade (base material)
3 α phase 4 β phase 5 TiB particles

Claims (2)

  A blade comprising a base material having a titanium alloy composed of at least one of an α phase and a β phase mainly composed of titanium, and TiB particles dispersed in the titanium alloy.   The blade according to claim 1, wherein a part of the TiB particles is exposed on the surface of the titanium alloy.

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