JP2001205519A - Metal saw - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal saw suitable for cutting hard-to-cut material such as stainless steel and Ti- or Ni-based super-heat resistant alloy. SOLUTION: A sintered alloy comprising one or two sorts of TiN and TiCN with hard grain dispersed by 0.5-15 mass % in matrix mainly comprising Fe in which one or two sorts of type MC and type M6C carbides are dispersed is provided. A metal saw using this sintered alloy is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal saw having a long cutting life.

[0002]

2. Description of the Related Art Among various uses using a sintered alloy, a metal saw used for cutting a metal is particularly required to have a long life characteristic. The blade material of the metal saw is roughly classified into a high-speed tool steel material and a cemented carbide material. Of these, a metal saw made of cemented carbide is widely used in which only the cutting edge portion is made of cemented carbide and brazed to a body material in order to cover the high price and low toughness of cemented carbide. Cemented carbide metal saws are capable of high-speed, high-efficiency cutting due to the excellent cutting characteristics and heat resistance of cemented carbide, and are gradually being used widely, but when the rigidity of the cutting machine is insufficient However, there is a disadvantage that the cutting edge is apt to be broken due to the low toughness of the cemented carbide, and there is a problem that it is difficult to apply to a generally used low rigidity automatic machine and a widely used manual machine. On the other hand, those made of high-speed tool steel are also widely used materials for cutting tools from the past, and due to their high toughness, they can be used on low-rigidity machines regardless of automatic machines or manual machines. . Since this high-speed tool steel metal saw has a high hardness by heat treatment, it is difficult to apply in terms of heat resistance, because during high-speed cutting, the metal saw itself is tempered and the hardness decreases, On the other hand, the blade is less likely to chip and has versatility compared to a metal saw made of cemented carbide.

[0003]

In order to improve the life of the above-mentioned metal saw made of high-speed tool steel, various studies have been made on components. Above all, one direction aims to improve the life by increasing the alloy of the components and increasing the hardness. It has been confirmed that the life of a high-speed tool steel metal saw for cutting JIS SCM materials, low alloy materials and the like is greatly improved by these methods. However, when cutting difficult-to-cut materials such as stainless steel and heat-resistant alloys containing a large amount of Ni, although the hardness of these cut materials is not high, the amount of heat generated during cutting is high because the cut materials are sticky. Many,
The increase in cutting load due to the welding of the material to be cut to the cutting edge causes the life, and the above-mentioned high alloying and high hardness have not yielded significant effects. It is difficult to extend the life. An object of the present invention is to improve the welding resistance of a cutting edge portion, which has been difficult with high alloying and high hardness of high speed tool steel, and to extend the life.

[0004]

In order to solve the above-mentioned problems, the present inventor has set the cutting edge of a stainless steel, a heat-resistant alloy containing a large amount of Ni, or a cutting material having a low hardness such as Ti, and welded to the cutting edge. As a result of various investigations on the method of suppressing the above, it is found that one or two of hard particles TiN and TiCN are dispersed in the alloy instead of high alloying and high hardness in high speed tool steel as described above. As a result, the present inventors have found that it is possible to remarkably improve the welding resistance and to improve the life at the time of cutting, and have reached the present invention.

That is, according to the present invention, TiN and TN, which are hard particles, are added to a matrix containing Fe as a main component in which one or two of MC and M ₆ C type carbides are dispersed.
A metal saw characterized by using a sintered alloy in which one or two kinds of iCN are dispersed as a cutting edge.

In the present invention, the hard particles T
A metal saw characterized in that at least the cutting edge is a sintered alloy in which one or two of iN and TiCN are contained in a mass ratio of 0.5 to 15% with respect to the entire sintered alloy.

[0007] In the matrix, the mass ratio of the matrix is Ceq = 0.06Cr + 0.063M.
When o + 0.033W + 0.2V, C is 0.5 to
A metal saw characterized in that a sintered alloy that satisfies 2.5 mass% and satisfies −0.2 ≦ C-Ceq ≦ 0.3 is at least a cutting edge.

The matrix is composed of 2% by mass or less of Si, 2% by mass or less of Mn, 6% by mass or less of Cr, 15% by mass or less of W, 14% by mass or less of Mo, 10% by mass or less of Co,
A metal saw characterized in that a sintered alloy containing 10% by mass or less is used at least as a cutting edge.

The matrix is composed of 3 to 5% by mass of Cr, 1 to 13% by mass of W, 0.5 to 12% by mass of Mo, V1
To 8% by mass, and more preferably Cr3 to 5%.
Mass%, W4 to 13 mass%, Mo1 to 7 mass%, V1 to
It is preferably 8% by mass.

The matrix satisfies the relationship of W + 2Mo <18 in the mass ratio of the matrix.

Further, it is preferable that the metal saw of the present invention has a cutting edge portion made of a sintered alloy having the above-mentioned components, and a portion other than the cutting edge portion is made of an ingot alloy having higher toughness than the cutting edge portion.

Further, in the present invention, it is preferable that the joint portion between the cutting edge portion and the base metal portion of the metal saw is provided with an uneven shape, and the cutting edge portion and the base metal portion are fitted and brazed.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
In one embodiment of the present invention, TiN and Ti, which are hard particles, are added to a matrix containing Fe as a main component in which one or two of MC type and M ₆ C type carbides are dispersed.
This is a metal saw having a cutting edge made of a sintered alloy in which one or two kinds of CN are dispersed. In order to cut the metal, the metal must be at least harder than the metal to be cut. By dispersing one or two of the MC type and M ₆ C type carbides, an appropriate hardness can be obtained. In addition, by dispersing one or two of TiN and TiCN that are hard particles, a reaction with a material to be cut hardly occurs,
It is possible to remarkably improve the welding resistance, thereby preventing an increase in cutting load, and extending the life of the metal saw. 1 and 2 show a scanning electron microscope (S
1 shows an example of a cross section of the sintered alloy of the present invention observed by (EM). From FIGS. 1 and 2, in the sintered alloy containing Fe as a main component,
It can be seen that white M ₆ C-type carbide, gray MC-type carbide and black hard particles TiN are dispersed.

In the present invention, in particular, in cutting materials having a low hardness, such as stainless steel, heat-resistant alloys containing a large amount of Ni, and Ti, in order to suppress settling of the cutting edge and welding to the cutting edge,
One or two of hard particles TiN and TiCN are included. In the present invention, among various hard particles,
The reason for choosing TiN or TiCN is that all of these hard particles contain nitrogen, and since Fe and N do not form a compound, they do not easily react with the material to be cut and significantly improve the welding resistance. However, it is possible to prevent an increase in cutting load due to this, and it is possible to extend the life of the metal saw. In this case, the addition amount of the hard particles is preferably 0.5 to 15% by mass. If the addition amount is less than 0.5% by mass, the effect of improving the welding resistance cannot be sufficiently exerted. On the other hand, as the addition amount increases, the welding resistance can be improved. The amount of addition is naturally limited due to the disadvantage that the grindability is deteriorated when the steel is machined. The upper limit of the addition amount that can improve the welding resistance without significantly lowering the grindability may be 15% by mass. When the amount of the hard particles exceeds 15% by mass, sintering becomes difficult, which is one of the reasons for setting the upper limit to 15% by mass.

The matrix of the sintered alloy constituting the cutting edge of the metal saw of the present invention preferably has a C content of 0.5 to 2.5% by mass and satisfies -0.2 ≦ C-Ceq ≦ 0.3. Here, the reason why the C amount is set to 0.5 to 2.5% by mass is as follows.
If the amount of C is less than 0.5% by mass, C becomes Cr, W, M
o, V and one or two of the MC type and M ₆ C type carbides are formed to impart wear resistance and to increase the hardness of the martensitic matrix by heat treatment of quenching and tempering. However, if the content exceeds 2.5% by mass, carbides are excessively precipitated to inhibit toughness and hot workability, or to deteriorate grindability when working into a tool shape.

The above carbide forming elements Cr, W, M
The equilibrium carbon amount Ceq at which o and V combine to form a carbide by an appropriate amount is given by the following formula: Ceq = 0.06Cr + 0.063Mo + 0.033W
+ 0.2V. Based on this, -0.2 ≦ CC
The reason why eq ≦ 0.3 is that when C-Ceq satisfies this range, when used for a metal saw, it is possible to obtain appropriate hardness for easily performing cutting. C-
If the Ceq is less than -0.2, the amount of C becomes insufficient, so that it becomes impossible to form MC type and M ₆ C type carbides, and it becomes impossible to obtain appropriate hardness. Also, C-Ce
This is because if q exceeds 0.3, the decomposition temperature of retained austenite shifts to a higher temperature side, so that the hardness is rather reduced.

The matrix component of the sintered alloy constituting the cutting edge of the metal saw of the present invention preferably satisfies the following component range. That is, Ceq = 0.06C
When r + 0.063Mo + 0.033W + 0.2V, C is 0.5 to 2.5% and -0.2 ≦ C-Ceq ≦
0.3, not more than 2% by mass of Si, not more than 2% by mass of Mn, not more than 6% by mass of Cr, not more than 15% by mass of W, not more than 14% by mass of Mo, not more than 10% by mass of V, not more than 10% by mass of Co, the balance being Fe and inevitable impurities Having a composition,
It is a matrix in which MC type and M ₆ C type carbides are dispersed. In addition, hard particles TiN and TiC
It is preferable that one or two of N are dispersed and combined by sintering. Further, preferably, Cr3 to
5% by mass, W1 to 13% by mass, Mo 0.5 to 12% by mass, V1 to 8% by mass, more preferably Cr3 to
5% by mass, W4 to 13% by mass, Mo1 to 7% by mass, V1
It is preferable to satisfy ８8% by mass.

While Si and Mn have a deoxidizing effect, if they are added in large amounts, they have problems such as impairing toughness. Therefore S
Both i and Mn were set to 2% by mass or less by mass.

Cr has the effect of improving the quench hardenability. However, when the content exceeds 6% by mass, the amount of retained austenite increases and the tempering hardness decreases. Therefore, the content of Cr is set to 6% by mass or less. In order to further improve the above-described effects, the Cr content is preferably 3 to 5% by mass. If the content is less than 3% by mass, it is difficult to enhance the quench hardening property. Also, when the content is 5% by mass or less, the tempering hardness can be further maintained.

W and Mo combine with C to form M ₆
It has the effect of forming C-type carbides and increasing wear resistance. In addition, it has the effect of forming a solid solution in the matrix during quenching, precipitating as fine carbides during tempering, and promoting secondary hardening. However, when the content exceeds W15% by mass and Mo14% by mass, the toughness of the material is reduced.
Hereinafter, Mo was set to 14% by mass or less. In order to obtain more favorable effects as described above, W1 to 13% by mass, M
It is preferably 0.5 to 12% by mass. If the content of W is less than 1% by mass and the content of Mo is less than 0.5% by mass, it is difficult to obtain the effect of increasing the wear resistance. In addition, W13% by mass or less, Mo
By setting the content to 12% by mass or less, the toughness of the material can be maintained. Further, in order to further improve the above-described effects, it is preferable that W is 4 to 13% by mass and Mo is 1 to 7% by mass.

In the composition of the sintered alloy of the present invention, W and Mo each satisfy W + 2Mo <18. W + 2M
By setting the o amount to less than 18, it is possible to increase the toughness and reduce the price while making the material appropriate hardness.

V combines with C to form mainly MC type carbide. MC type carbide is higher in hardness than M ₆ C type carbide, and has a great effect in enhancing wear resistance. On the other hand, if a large amount of V is added to increase the amount of MC carbide more than necessary, the workability of the material, particularly the grindability, is reduced.
Therefore, V is set to 10% by mass or less. In order to obtain a more favorable effect as described above, the content is preferably V1 to 8% by mass. This is because if it is less than 1% by mass, it is difficult to form MC-type carbides, and it is difficult to increase wear resistance. Further, by setting the content to 8% by mass or less, the workability of the material, particularly, the grindability can be maintained.

Co is dissolved in the matrix and has a tempering hardness.
Has the effect of increasing high-temperature hardness. However, if the content exceeds 10% by mass, the toughness is reduced.
It was as follows.

The sintered alloy used for the cutting edge of the metal saw of the present invention has excellent welding resistance and grindability by dispersing hard particles. It is clear that by using the metal saw, it is possible to suppress the reaction with the material to be cut and, as a result, to prevent an increase in the load on the metal saw during cutting. Here, only the cutting edge portion may be made of a sintered alloy. In this case, it is possible to prevent breakage of the entire blade by using a high-performance sintered alloy only for the blade edge portion and a tougher molten alloy, preferably a forged alloy, for the base metal portion. It is possible.

When the cutting edge portion having the cutting edge of the metal saw is joined to the base metal portion, it is preferable that the joint portion is provided with a concave-convex shape so that both can be fitted together. By forming the joining portion in an uneven shape, joining is facilitated, and the joining portion is firmly fixed. Further, it is preferable that the cutting edge portion and the base metal portion are fitted and the fitting portion is joined and fixed using a brazing. Here, the brazing is easy to handle and the bonding can be made stronger.

[0026]

The present invention will be described in more detail with reference to the following examples. First, high-speed tool steel powder having the chemical composition shown in Table 1 was produced by a water atomizing method. At this time, one or two of the MC type and M ₆ C type carbides were dispersed, and the average particle diameter of the high-speed steel powder, which became a sintered alloy containing Fe as a main component, was 11 μm.

[0027]

[Table 1]

After mixing the above powder with various amounts of TiN powder, a 50.times.100 mm plate-like compact was formed by press molding and sintered. Here, it was confirmed that the sintered alloy was a sintered alloy in which hard particles TiN were dispersed. The density after sintering is as follows.
By doing so, almost true density was obtained. The sintered body is subjected to heat treatment of quenching and tempering, and has a hardness HR
After having a hardness of C65 or more, the cutting edge member was cut out by wire cutting. An appropriate concavo-convex shape was provided on a portion of the blade member opposite to the blade edge so that a fitting structure with the base metal was possible. FIG. 3 is a plan view showing an example of the shape of the metal saw before the blade is cut. The cutting edge member 1 was fitted to the outer peripheral portion of a circular steel plate 2 of carbon tool steel SK3 serving as a base metal, and was joined and fixed using a braze.

After cutting the sintered alloy cutting edge member located on the outer peripheral portion of the cutting blade constituted as described above, the cutting blade was subjected to a cutting test. The material to be cut is φ25-40
The life test of the cutting blade was performed using carbon steel S45C, chromoly steel SCM435, stainless steel SUS316, and 718 alloy which is a Ni-based super heat-resistant alloy. The life was evaluated by the number of times that the motor could be cut before the motor load was overloaded and stopped. Table 2 shows the evaluation results.

[0030]

[Table 2]

As is clear from Table 2, it can be seen that in any cutting of the material to be cut, the cutting life is greatly improved with the addition of TiN in the range of addition of TiN of 0.5 to 15% by mass. . When the amount of TiN is set to 17% by mass, sintering to a true density becomes impossible,
I couldn't make a metal saw with this one. Therefore, the life test of the cutting blade could not be performed.

[0032]

As described above, MC type and M ₆ C
One or two types of carbides of the type are dispersed, and the cutting edge portion is formed using a sintered alloy in which one or two types of hard particles TiN and TiCN are dispersed in a matrix mainly containing Fe. It is clear that the produced metal saw can improve the welding resistance and the grindability, suppress the reaction with the material to be cut, and as a result, can prevent an increase in the load on the metal saw during cutting.

[Brief description of the drawings]

FIG. 1 is a cross-sectional micrograph at × 2,000 magnification showing an example of a sintered alloy constituting a metal saw of the present invention.

FIG. 2 is a cross-sectional photomicrograph at 5,000 times magnification showing an example of a sintered alloy constituting a metal saw of the present invention.

FIG. 3 is a plan view showing an example of a metal saw shape according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cutting edge member 2 Base metal part 3 Fitting structure part which forms unevenness

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[Procedure amendment]

[Submission date] February 14, 2000 (2000.2.1
4)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

Claims (9)

[Claims] (1) one of MC type and M ₆ C type carbides:
A metal saw comprising a sintered alloy in which one or two of TiN and TiCN, which are hard particles, are dispersed in a matrix containing Fe as a main component in which seeds or two kinds are dispersed. 2. The hard particles are one or two of TiN and TiCN, and the content ratio of the hard particles is 0.5 to 15% by mass in the sintered alloy. The metal saw according to 1. 3. The matrix has a Ceq = 0.06Cr + 0.063Mo +
When 0.033W + 0.2V, C is 0.5 to 2.5
3. The metal saw according to claim 1, wherein the metal saw has a composition satisfying mass% and −0.2 ≦ C-Ceq ≦ 0.3. 4. 4. The matrix is composed of Si 2% by mass or less,
n2 mass% or less, Cr6 mass% or less, W15 mass% or less, Mo14 mass% or less, V10 mass% or less, Co10
The metal saw according to any one of claims 1 to 3, having a composition of not more than mass%. 5. A matrix comprising 3 to 5% by mass of Cr and W
The metal saw according to claim 4, having a composition of 1 to 13% by mass, 0.5 to 12% by mass of Mo, and 1 to 8% by mass of V. 6. A matrix comprising 3 to 5% by mass of Cr and W
The metal saw according to claim 5, having a composition of 4 to 13% by mass, Mo 1 to 7% by mass, and V1 to 8% by mass. 7. A metal saw, wherein the matrix satisfies W + 2Mo <18 in a mass ratio of the matrix. 8. A metal saw, wherein a cutting edge portion is made of the sintered alloy according to claim 1, and a portion other than the cutting edge portion is made of an ingot alloy having higher toughness than the cutting edge portion. 9. The metal saw according to claim 8, wherein
A metal saw characterized in that an uneven shape is provided at a joint portion between a cutting edge portion and a base metal portion, and the cutting edge portion and the base metal portion are fitted and brazed.