JP2005048276A - Method of producing cutter stock, and cutter stock thereby - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of producing a cutter stock consisting of lightweight cemented carbide, and having a low specific gravity while maintaining high wear resistance and high hardness, and to provide a cutter stock thereby. <P>SOLUTION: The method of producing a cutter stock comprises the following stages: a stage where, by weight, 10 to 90% vanadium carbide (VC) powder (the first stock) having specific gravity of ≤7 and 10 to 90% titanium (Ti) or titanium (Ti) alloy powder (the second stock) having specific gravity of ≤7 are mixed to prepare a powdery mixture of the first and second stocks; a stage where the powdery mixture is packed into a compacting die, and is thereafter compacted to obtain a compact; and a stage where the compact is sintered at ≤1,500°C. The obtained sintered compact has hardness of ≥60 by HRA and specific gravity of ≤7. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a knife including a cooking knife, a round shape, and a square shape, and more particularly to a cutlery material made of a cemented carbide although being lightweight and a manufacturing method thereof.

  For knives, knives, round rotary swords, square razors, etc., conventionally punched and rolled steel sheets and then heat treated and hardened to produce a blade (cutter). Was the majority.

  In the above-described conventional blades, long-lasting properties are desired as the first performance. For this reason, attempts have been made to improve the hardness of steel for cutting tools, but conventional carbon steel has a problem that brittleness increases as the hardness increases during quenching.

  Furthermore, there are powder sintered blade materials mainly composed of tungsten carbide (WC) powder and cobalt (CO) powder, but the disadvantage of such blade materials is that their specific gravity is heavy, 10-16 depending on their composition. And there was a limitation in use.

  The present invention has been proposed in order to solve the above-mentioned problems, and an object of the present invention is a lightweight cutter material having a small specific gravity while maintaining high wear resistance and hardness. It is in providing a manufacturing method and the blade material by this.

  In order to achieve the above object, the present invention provides a vanadium carbide (VC) powder (first material) having a specific gravity of 7 or less, 10 to 90% by weight, titanium (Ti) having a specific gravity of 7 or less, or titanium ( (Ti) Alloy powder (second material) is mixed by 10 to 90% by weight to prepare a mixed powder of the first and second materials, and the mixed powder is filled in a molding die and then pressed and molded. And a step of sintering the molded article at a temperature of 1500 ° C. or less, wherein the sintered molded article has a hardness of HRA 60 or more and a specific gravity of 7 or less.

  As described above, according to the present invention, it is possible to obtain a lightweight cemented carbide blade material that maintains a low specific gravity while having a high hardness. In addition, it is possible to manufacture a cutter material of a smaller volume with the same weight, or a cutter material of a smaller weight with the same volume, thus reducing raw materials and costs, easy manufacturing due to product miniaturization, and lightweight product It is possible to have the effect of reducing the driving power of the blade driving power in the mechanical device by the conversion.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a perspective view of a round blade cutter which is an embodiment manufactured by the method for manufacturing a blade material according to the present invention, and FIG. 2 is a cross-sectional view of the round blade cutter shown in FIG.

  In the above embodiment, vanadium carbide (VC) is used as the main material of the blade material. The hardness of vanadium carbide (WC) as a conventional powder sintered blade material is Micro Vickers HV = 1780, whereas the hardness of vanadium carbide (VC), which is the main material in the present invention, is Micro Vickers HV = 2600. There is a higher hardness, and the specific gravity of the bonded sintered body of vanadium carbide and titanium (Ti) or titanium (Ti) alloy is 5-7 depending on the composition, and the specific gravity of WC / CO cemented carbide It is particularly preferable as the main material because it can be reduced in weight by about 1/2 to 1/3 as compared with 10-16.

  On the other hand, the hardness at the time of quenching of the conventional carbon steel blade material is usually about HV-820 / HRA84, and the hardness is limited, and the specific gravity at this time is about 8.5. On the other hand, in the WC-CO cemented carbide, HV1800 (HRA92) is almost the upper limit, but the specific gravity is about 15. On the other hand, the hardness of vanadium carbide (VC), which is the main material of the present invention, is HV2600, which is very high, but its specific gravity is as light as about 7, which is preferable for realizing weight reduction and high hardness of the blade material. .

  The manufacturing method of the round blade cutter raw material of FIG.1 and FIG.2 which is one Embodiment of this invention is demonstrated.

  First, vanadium carbide (VC) powder having a specific gravity of 7 or less is used as a first material, and 10 to 90% by weight is prepared, and titanium (Ti) or titanium (Ti) alloy powder having a specific gravity of 7 or less is used as a second material. After preparing 10 to 90% by weight, the first and second materials are mixed to prepare a mixed powder.

  Here, the vanadium carbide weight percentage was set to 10 to 90 wt% because the vanadium carbide content is 10 wt% or less with respect to the total weight of the mixed powder, or the wear resistance is low or the hardness is low. This is because if the amount is 90% by weight or more, the hardness becomes too high and the brittleness increases.

  Next, a mixed powder of vanadium carbide (first material) powder and titanium or titanium alloy powder (second material) having the above-described composition is filled in a molding die having a desired shape, and then 10 t per square centimeter (cm). Press-molding with the applied pressure to obtain a molded product.

  The molded product is taken out from the mold and sintered in a vacuum furnace at a temperature of 1500 ° C. or lower, preferably about 1300 ° C. to obtain a round blade cutter material as shown in FIG.

  The blade material shown in FIGS. 1 and 2 is a rotary blade material that is mounted on a rotating shaft of a machine and rotates, and is provided with a rotating shaft insertion hole 1 and a plane having a desired thickness by surface grinding. After the grinding part 3 is formed, the outer peripheral edge grinding part 2 is formed and completed by performing edge grinding on the peripheral surface of the outer periphery.

  The sintered molded article has a hardness of about HRA 60 when vanadium carbide is 10% by weight with respect to the total weight of the mixed powder.

  The second embodiment of the present invention is to add silver powder as the third material to the mixed powder of the first material and the second material in order to improve the antibacterial and hygienic properties of the blade material. .

  For example, when manufacturing a round blade cutter material and using it as a blade for cutting foods such as animals and plants, it is hygienic in addition to the long-lasting performance of the work tool. Maintenance is required. For this reason, when used for cutting food, silver is added to the lightweight cemented carbide blade material of the blade material of the present invention.

  If silver is added to the lightweight cemented carbide blade material, antibacterial performance due to silver ions can be imparted to the blade material, so even if the blade is contaminated by blood or meat pieces of cut meat, the antibacterial property due to silver ions And the self-cleaning function is desirable to maintain the hygiene of the blade material.

  When silver powder is mixed with vanadium carbide powder, titanium or titanium alloy powder, when silver powder is 0.3 wt% or less with respect to the total powder weight of vanadium carbide, titanium or titanium alloy powder and silver powder Antibacterial performance due to silver ions is difficult to expect, and good antibacterial performance can be obtained up to about 3% by weight, but if it is 3% by weight or more, it is difficult to expect further increase in antibacterial performance. It is also disadvantageous in terms of cost.

  On the other hand, vanadium carbide (VC), which is the first material in the present invention, is the main material of a lightweight cemented carbide material due to its high hardness and lightness, but titanium, which is the second material, has the first material particles as a whole. It acts as a bonding material for sintering as a bonded body.

  On the other hand, if the molded product is pressurized and sintered, pores are easily generated in the structure of the sintered body, and the degree of the generation of pores generally varies depending on the pressure applied during molding. Furthermore, the pores existing in the sintered body lower the actual density of the sintered body, and if the pores are present at the edge of the tool part, the cutting force is reduced.

  Therefore, in order to solve such a problem, 2 wt% to 25 wt% of cobalt powder is added to the mixed powder of the first material and the second material.

  As described above, if the cobalt powder is added to the mixed powder and pressed and sintered, the cobalt powder easily liquefies and has high fluidity at a high temperature during sintering. It flows into the pores generated in the body and closes the pores. If the pores are filled in this way, the pores are eliminated and at the same time the density strength of the sintered structure is increased.

  At this time, if the amount of cobalt is 2% by weight or less, it is insufficient to fill the pores generated in the sintered structure, and if it is 25% by weight or more, the remaining cobalt remains after filling the pores generated in the sintered body. However, there is a problem that segregation occurs due to uneven distribution in the sintered body.

  Although the specific gravity of Kovardo is relatively heavy at about 8.9, the product specific gravity can be finally reduced to about 7 or less by adjusting the blending amount with vanadium carbide. As a result, the specific gravity of the cemented carbide can be greatly reduced.

It is a perspective view of the round blade cutter manufactured by the blade material manufacturing method by this invention. It is sectional drawing of the blade raw material of FIG.

Explanation of symbols

1 Rotating shaft insertion hole 2 Peripheral blade grinding part 3 Surface grinding part

Claims (4)

10 to 90% by weight of vanadium carbide (VC) powder (first material) having a specific gravity of 7 or less, 10 to 90% by weight of titanium (Ti) or titanium (Ti) alloy powder (second material) having a specific gravity of 7 or less. % To prepare a mixed powder of the first and second materials,
A step of filling the mixed powder into a molding die and then press-pressing to obtain a molded product;
Sintering the molded article at a temperature of 1500 ° C. or less,
The sintered molded article has a hardness of HRA 60 or more and a specific gravity of 7 or less.   The method for manufacturing a blade material according to claim 1, further comprising adding 0.3 to 3 wt% of silver powder to the mixed powder.   The method for manufacturing a blade material according to claim 1, further comprising adding 2 to 25 wt% of cobalt powder to the mixed powder. A blade material manufactured by the method for manufacturing a blade material according to claim 1.