JPH1071507A - Coated hard metal tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve wear resistance without deteriorating chipping resistance. SOLUTION: A hard metal base member 1 which has a cutting edge treatment on a cutting edge ridgeline 3 that is a joint part of a flank face and a cutting face 6, and a coating film 2 coated on the surface of the base member 1, are provided. The cutting edge ridgeline 3 of the coating film 2's surface has a surface treatment, and the coating film 2 is formed in a way that Rc1/(Rs1+ d)<1.0 is satisfied, where the radius of curvature formed in the boarder line between the flank face and the cutting edge treatment part on the surface of the base member 1 is Rs1, the radius of curvature of a round convex formed in the boarder line between the flank face and the surface treatment part on the surface of the coating film 2 is Rc1, and the average thickness of the area out of the edge treatment part of the coating film 2 is d.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated hard alloy tool, and more particularly to a surface for increasing the thickness of a coating film on a hard alloy substrate and specifying the shape of a cutting edge ridge after coating. The present invention relates to a technique for improving abrasion resistance without impairing fracture resistance by performing a treatment.

[0002]

2. Description of the Related Art Conventionally, as a material of a tool for cutting a metal material, a cemented carbide (WC-Co alloy or WC-Co alloy) is used.
An alloy obtained by adding a carbonitride of Ti, Ta, or Nb to an alloy) has been used. However, in recent years, as cutting conditions have been accelerated, the surface of a substrate made of cemented carbide or cermet, or a substrate made of alumina-based or silicon nitride-based ceramics, has been subjected to a CVD (Chemical Vapor Deposition) method or PVD ( The use of hard alloy tools in which coating films of various materials are coated to a thickness of 3 to 15 μm by the Physical Vapor Deposition method is increasing. Examples of the material of the coating film include Group IVa, Va, and VIa metals of the Periodic Table of the Elements and A
For example, carbides, nitrides, carbonitrides, carbonates, boronitrides, oxides, or solid solutions thereof are used. Also, a coating film made of diamond or diamond-like carbon has been used.

[0003] These coated hard alloy tools form a cutting edge shape by chamfering a hard alloy base material by honing, chamfering, or a combination thereof, and thereby, the fracture resistance of a hard alloy which is easily broken. After coating, the coating process is performed. Further, in order to improve the wear resistance, there is a known technique for forming a multilayer coating film.

Further, Japanese Patent Publication No. 5-9201 discloses that a part of a coating film on a ridge of a cutting edge is removed by a surface treatment after a coating treatment on a surface of a hard alloy substrate, thereby improving the edge strength. A technique for improving the wear resistance is disclosed.

[0005]

However, in each of the above-mentioned conventional coated hard alloy tools, when the processing amount of the cutting edge of the hard alloy base material is increased, the chipping resistance is improved, but the wear resistance is reduced and the cutting edge processing is reduced. When the amount is reduced, the problem due to the conflicting phenomenon that the wear resistance is improved but the fracture resistance is reduced has not been sufficiently avoided.
In addition, the technique described in Japanese Patent Publication No. 5-9201 also has a problem that it is not always possible to improve both the fracture resistance and the wear resistance depending on the degree of removal of the coating film. .

According to the present invention, there is provided a tool for improving wear resistance without deteriorating chipping resistance by optimizing both the shape of a hard alloy substrate and the shape of a coating layer at the cutting edge of a coated hard alloy tool. It is an object to provide a coated hard alloy tool with a long life.

It is another object of the present invention to provide a long-life coated hard alloy tool having improved fracture resistance and wear resistance.

[0008]

According to the present invention, there is provided a coated hard alloy tool for achieving the above object, comprising: a hard alloy base having a cutting edge processing portion at a cutting edge ridge portion which connects a flank and a rake face; A coating film coated on the surface of the hard alloy base material, and a surface treatment portion on a cutting edge ridge portion of the surface of the coating film. The feature of the coated hard alloy tool is that the radius of curvature of the convex curved surface formed at the boundary between the flank and the cutting edge processing portion on the surface of the hard alloy substrate is Rs1, and the flank and the surface treatment are formed on the surface of the coating film. Rc1 / (Rs1 + d) <where Rc1 is the radius of curvature of the convex curved surface formed at the boundary with the portion and d is the average thickness of the coating film in the region other than the surface-treated portion.
That is, the coating film is formed so as to be 1.0.

According to this structure, Rc1 / (Rs1 +
d) By forming the coating film so as to satisfy <1.0, it is possible to improve the wear resistance without impairing the chipping resistance.

The process by which the present inventors have found the structure of the present invention by paying attention to the relationship between the curvature radii of the cutting edges of both the hard alloy substrate and the coating layer is as follows.

The fracture resistance of a coated hard alloy tool depends on the coated base metal.
Toughness determined by the material of the hard alloy base material, and
It is governed by the shape of the cutting edge of the hard alloy substrate before coating
Is already known. Usually a hard alloy substrate blade
The tip shape is alumina or Zr0 _Two Such as oxide coated
In the case, the coating thickness is maximized at the corners forming the cutting edge ridge
Easier to do. Therefore, the flank and surface-treated cut
The radius of curvature of the coating film surface at the boundary with the blade is Rc1,
The corresponding radius of curvature of the surface of the hard alloy substrate is Rs1,
And d is the average film thickness of the coating film in the region other than the surface treatment part.
Satisfies Rc1> Rs1 + d
Often it is. However, the alumina film coating
H as raw material gas during_Two Membrane at the corners using S
By using the technology to suppress the maximum thickness,
Almost uniform, satisfying the relationship of Rc1 = Rs1 + d on the cutting edge
It is possible to form a coating film having a thickness.

Since the magnitude of the curvature radius Rc1 determines the sharpness of the tool, the sharpness of the tool after the coating process is slightly reduced as compared with the case where the coating process is not performed.
Abrasion resistance also deteriorates at the same time. This tendency became larger as the thickness of the coating film increased, and it was found that the tendency was particularly remarkable when the coating film thickness was 15 μm or more.

Therefore, in order to improve the wear resistance while maintaining the toughness, the radius of curvature Rs1 at the boundary between the flank of the hard alloy substrate and the cutting edge portion treated with the cutting edge is made larger than that of the conventional tool. An attempt was made to perform a coating treatment so that the coating film thickness was larger than before, and then to perform a surface treatment of the coating film.

At this time, Rc1 is reduced and Rc1 is reduced.
It has been discovered that by performing a cutting edge treatment so as to obtain a cutting edge shape that satisfies the relationship of 1 <Rs1 + d, it is possible to improve wear resistance without impairing chipping resistance.

In the coated hard alloy tool of the present invention, in the above structure, the radius of curvature of the convex curved surface formed at the boundary between the rake face and the cutting edge processing portion on the surface of the hard alloy base is Rs.
2. When the radius of curvature of the convex curved surface formed at the boundary between the rake face and the surface-treated portion on the surface of the coating film is Rc2, the surface is further coated so that Rc2 / (Rs2 + d)> 1.0. It is preferable that a covering film is formed. Thus, Rc1 / (Rs1 + d) <1.0 and Rc2 /
By satisfying both the relations of (Rs2 + d)> 1.0, both the fracture resistance and the wear resistance can be improved.

Further, in order to further exert the effect of improving the fracture resistance and the wear resistance, Rc1 / (Rs1 + d)
And Rc2 /
It is preferable that (Rs2 + d) is formed to be 2.0 or more and 5.0 or less.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

First, referring to FIG. 1, a coating film 2 is coated on the surface of a hard alloy substrate 1 on which a cutting edge ridge 3 forming a connecting portion between a flank 4 and a rake face 6 has been subjected to a cutting edge treatment. The surface of the coating film 2 is further subjected to a surface treatment so that
By forming the surface-treated portion on the surface, a coated hard alloy tool having a sectional shape shown in FIG. 1 is formed.

In the coated hard alloy tool shown in FIG. 1 formed as described above, the radius of curvature of the convex curved surface formed at the boundary between the flank 4 and the cutting edge processing portion on the surface of the hard alloy substrate 1 is determined by Rs1, flank surface 4 on surface of coating film 2
Rc1 / (Rs1 + d) <1.0, where Rc1 is the radius of curvature of the convex curved surface formed at the boundary between the surface and the surface treatment, and d is the average thickness of the coating film 2 in the region other than the surface treatment. The edge treatment portion of the hard alloy substrate 1 and the surface treatment portion of the surface of the coating film 2 are formed so as to satisfy the relationship of Rc2 / (Rs2 + d)> 1.0.

Thus, Rc1 / (Rs1 + d) <
By satisfying both the relations of 1.0 and Rc2 / (Rs2 + d)> 1.0, both fracture resistance and wear resistance can be improved. In addition, at least Rc1
By satisfying only the relationship of /(Rs1+d)<1.0, the wear resistance can be improved without impairing the fracture resistance.

The relationship represented by these inequalities is the cutting edge 3 of the throw-away tip 7 shown in FIG.
Is preferably formed so as to cover all the cutting edges of the nose R portion 8, but even if it is formed in a part thereof, a certain effect is exhibited.

The value of the radius of curvature Rc1 is measured as follows. First, after cutting the coated hard alloy tool having the surface treated with the coating film 2 in a cross section perpendicular to the cutting edge, the cut surface is embedded in resin. This is subjected to surface grinding and mirror polishing, followed by etching, and then, if necessary, gold deposition. Next, the vicinity of the cutting edge ridge portion of the sample formed in this way was measured with an optical microscope at 1500.
Shoot at double magnification. Next, the photographed image is taken into an image processing apparatus, and on the image, the boundary between the unprocessed portion of the coating film on the flank side and the surface-treated portion is set as a starting point (point O). A point (point A) 5 μm away from the rake face on the surface of the coating film and a point (point B) 5 μm away from point O to the flank side on the surface of the coating film from point O are determined. Based on the coordinates (x, y) of the points O, A, and B determined in this way, the radius of a circle passing through these three points is calculated, whereby the value of the curvature radius Rc1 is obtained. Radius of curvature Rc
2, Rs1 and Rs2 are obtained by the same method.

As a method of surface treatment of the coating film 2, a treatment method using a brush or an elastic grindstone containing a hard substance such as diamond or SiC is suitable, but is not limited to these methods. The shape of the cutting edge after surface treatment is affected by the rotational speed and hardness of the brush or grindstone, the processing angle of the tool with respect to the rake face, the pressing force of the grindstone, the presence or absence of cutting oil, and the like. Therefore, in order to obtain a desired cutting edge shape, it is necessary to appropriately set these conditions.

The material of the hard alloy substrate 1 may be cermet or ceramic (for example, silicon nitride or fiber reinforced ceramic (FRC)) in addition to cemented carbide.
These materials may have a gradient composition. As the gradient composition material, a material having a tough layer or a ceramic layer on the surface can be used. Materials constituting the coating layer 2 include IVa, Va, V in the periodic table of the elements.
Group Ia metals (ie, Ti, Zr, Hf; V, Nb, T
a; carbide, nitride, carbonitride, carbonate, boronitride or oxide such as Cr, Mo, W) or Al, or a solid solution thereof. Further, as a material of the coating layer 2, diamond, diamond-like carbon, or the like is used. The coating layer 2 is formed by a CVD method, a PVD method, or the like.

In the coated hard alloy tool of this embodiment,
When the average film thickness of the coating film of the hard alloy substrate is 15 μm or more, and the film thickness at the cutting edge ridge portion thinned by the surface treatment is dx, dx / d is 0.2 or more and 0 or more. .
8 or less.

In the conventional case where the thickness of the coating film 2 is constant, if the thickness exceeds 15 μm, Rc1 on the surface of the coating film 2 increases and the sharpness decreases. On the other hand, the average film thickness of the coating film 2 on the flank surface 4 which is a region where the cutting edge treatment is not performed is d, and the film thickness at the thinnest portion at the cutting edge ridge portion 3 thinned by the surface treatment is dx. When dx / d is in the range of 0.2 to 0.8, the thickness of the portion of the coating film 2 that has not been put into practical use and has not been reduced in thickness is reduced. The sharpness of a tool of 15 μm or more can be improved, and the wear resistance is improved. As a result, the thickness of the coating film 2 was 20 μm.
Practical use of a coated hard alloy tool having a thickness of ５０50 μm can be achieved.

Here, the reason why the value of dx / d is set to 0.2 or more is that if this value is less than 0.2, the time until the hard alloy substrate 1 is exposed due to the wear of the coating film 2 is exposed. Is extremely short, and the abrasion resistance is reduced. Even if the value is set to a value exceeding 0.8, no significant improvement in the fracture resistance is recognized.

It is preferable that the ratio Rs2 / Rs1 of the two radii of curvature of the hard alloy substrate 1 is formed to be 0.7 or more and 1.3 or less. Thus, Rs2 / R
When s1 is formed in the range of 0.7 to 1.3, the stress concentration of the cutting resistance acting on the cutting edge ridge portion 3 of the hard alloy base material 1 is reduced. As such a cutting edge method, a polishing method using a centrifugal barrel, a vibration barrel, or the like is preferable. These cutting edge treatment methods smooth the surface properties of the hard alloy substrate 1 (Rmax
(Less than 0.3 μm) is effective as an industrial means.
Here, if the ratio of Rs2 / Rs1 is less than 0.7, the abrasion resistance decreases, and if it exceeds 1.3, the fracture resistance decreases.

Further, it is preferable that the ratio Rc2 / Rc1 of the two radii of curvature of the surface of the coating film 2 is formed to be 2.0 or more and 50 or less. Thus, Rc2 / Rc1
Is in the range of 2.0 to 50, the balance between wear resistance and chipping resistance becomes very good. Rc2 /
If Rc1 is less than 2.0, the wear resistance deteriorates, and if it exceeds 50, the fracture resistance decreases.

As shown in FIG. 1, when the width of the rake face is a and the width of the flank is b, the ratio a / b is 1 .5 or more4.
Preferably, it is formed so as to be 0 or less. a / b
When the ratio is less than 1.5, the effect of improving the wear resistance is small, and when it exceeds 4.0, the fracture resistance is reduced.

The coating film 2 preferably has a multilayer structure including at least an oxide ceramic layer, and a part of the thickness of at least one of the oxide ceramic layers extends over the entire cutting edge ridge line region. It is preferable that the surface treatment is performed so as to remain. For example, as shown in FIG.
In the case where only one of the four coating layers 2 is a coated hard alloy made of the oxide ceramic layer 2a, after performing the cutting edge treatment of the coating film 2, the oxide ceramic layer 2a is changed to the state shown in FIG. As shown in FIG. 6), if a part of the thickness remains in the entire area of the cutting edge processing portion, good wear resistance is exhibited. However, the oxide ceramic layer 2a is hardened as shown in FIG. If even a part of the part is removed, the wear resistance may deteriorate.

More specifically, the occurrence of crater wear 9 at the position shown in FIG. 3 due to an increase in the cutting temperature during high-speed and high-efficiency cutting is caused by the fact that the oxide ceramic layer 2a exists at the cutting edge ridge portion 3. Greatly suppressed. In particular, when the ratio a / b is in the range of 1.5 to 4, the removal amount of the coating film on the rake face 6 side is increased by the surface treatment,
Since the area where the crater wear 9 is likely to occur and the contact surface of the chips 10 overlap, it is extremely effective to reduce the crater wear 9 by leaving the oxide ceramic layer.

The coated hard alloy tool of the present embodiment is set so that the increased surface area ratio in at least a part of the surface treatment portion of the coating film 2 is 0.1% or more and 1.3% or less. By setting the increased surface area ratio in the cutting edge ridge portion 3 after the surface treatment to 0.1 to 1.3%, in addition to improving both the fracture resistance and the abrasion resistance, the peeling resistance of the coating film is also improved. Performance can be improved. Although the peeling resistance of the coating film 2 is improved as the surface after the surface treatment is closer to the mirror surface, it is industrially difficult to treat the increased surface area ratio to be less than 0.1. Is 1.3
If it exceeds 300, no significant improvement in peeling resistance can be obtained. By improving the peeling resistance of the coating film 2, the degree of exposure of the hard alloy base material surface in the cutting edge processing portion during cutting is suppressed, so that the phenomenon of welding of the work material to the cutting edge processing portion is also suppressed. As a result, the fracture resistance of the tool can be further improved.

Here, the increased surface area ratio means that the measured visual field area is Sm and the surface area of the measured part is Sa, as shown in FIG.
Is a numerical value quantified by the mathematical formula of (Sa / Sm-1) × 100%. In other words, with respect to the surface area when the measurement visual field area
It shows the increase rate of the surface unevenness area of the measurement visual field area. The reason for quantifying the surface area with this value is that Rm
While conventional roughness indices such as ax and Ra can only express surface roughness properties in the height direction, this numerical value indicates information on three-dimensional surface roughness including surface roughness in the horizontal direction. Can be quantified.

The surface area Sa of the measuring section is obtained by sampling the coordinates of the position indicated by the black point in FIG. 4B in the direction of arrow M, and then sampling points x11 and x1 on the surface of the measuring section.
Areas s11, s12, of triangles with vertices at 2, x21, ...
Calculated as the sum of

[0036]

Examples Examples of the effects of the present invention will be described below.

Example 1 Rs1 at the cutting edge ridge of an ISO-P20 class throw-away insert having the shape of model number SNMG120408 is 60 μm.
m and Rs2 are processed to be 90 μm, and 0.5 μm TiN / 7 μm TiCN / 2 μm Al
_A ceramic coating (d = 10 μm) consisting of four layers of ₂ O ₃ /0.5 μm TiN was coated by a CVD method at a temperature of about 1000 ° C. When coating the alumina film, H ₂ S gas is used as a raw material to prevent the alumina film from maximizing at the edge portion, and a coating film having almost no difference in film thickness between the flat portion and the edge portion can be obtained. did it.

Next, this coated throw-away tip is
The rake angle with respect to the throw-away tip was changed with a nylon brush to which 400 diamond abrasive grains were adhered, and as shown in Table 1, throw-away tips having different Rc1 and Rc2 were prepared. Next, using these samples, four grooves 12 were formed on the outer periphery as shown in the cross section in FIG.
The work material 11 made of the high carbon steel SCM435 material provided with is intermittently cut under the following conditions, the fracture resistance of each sample is evaluated, and the work piece of the round bar made of the low carbon steel SCM415 material is used. The abrasion resistance was evaluated under the following conditions.

Fracture resistance test 1 Cutting speed 100 m / min Feed 0.2-0.4 mm / rev Depth of cut 2 mm Cutting oil None Holder PSUNR2525-43 The life time is the time from the start of cutting to the time of chipping, and The average life time of the four corners in the above was taken as the life time of the sample.

Abrasion resistance test 1 Cutting speed 300 m / min Feeding 0.3 mm / rev Cutting depth 1.5 mm Cutting time 30 minutes Cutting oil Yes The results are shown in Table 1 below.

[0041]

[Table 1]

As can be seen from the results shown in Table 1, Rc was lower than that of the comparative product 1-1 which had not been subjected to the surface treatment and the comparative product 1-2 which had been subjected to the surface treatment but did not fall within the scope of the present invention.
Invention products 1-1 to 1-6 in which 1 is smaller than Rs1 + d
Indicates that the wear resistance is improved without impairing the fracture resistance. Above all, Rc1 / (Rs + d) is set to 0.1.
Invention products 1-3 to 1-5 in the range of 2 to 0.8 show particularly excellent wear resistance.

Example 2 A sample was prepared by using a cermet-based throw-away chip of ISO-P20 class as a base material and coating the surface with a coating film having a thickness d of 10 to 22 μm. 1
Rc2, Rs using the same diamond brush as
2, Comparative products 2-1 having different values of Rc1 and Rs1 and invention products 2-1 to 2-7 were prepared. The test results are shown in the table below.

[0044]

[Table 2]

As can be seen from the results shown in Table 2, the invention product 2-1 was compared with the comparison product 2-1 outside the scope of the present invention.
~ 2-7 showed excellent fracture resistance and wear resistance. Among them, invention products 2-2 to 2-7 in which Rc2 / (Rs2 + d) is larger than 1.0 show particularly excellent cutting characteristics, and especially, Rc2 / (Rs2 + d) is 2.0 to 5.0.
Invention products 2-4 to 2-6 in the range of 0 exhibited excellent cutting performance.

Example 3 The same Rs1 (= 60) as the comparative product 1-1 prepared in Example 1 was used.
μm) and Rs2 (= 90 μm) on a hard alloy substrate, only the thickness of the TiCN film of the intermediate layer shown in Table 3 below was obtained.
Otherwise, the same coating film as in Example 1 was applied, and the surface was treated with a diamond brush in the same manner as in Example 1.
Inventive products 3-1 to 3-4 having m and 90 μm were subjected to the same wear resistance test as in Example 1. Table 4 shows the results.

[0047]

[Table 3]

[0048]

[Table 4]

From the results shown in Table 4, the thickness d of the coating film was 15 μm.
It can be seen that the degree of improvement in cutting performance of the invention products 3-2 to 3-4 thicker than m is particularly large.

Next, the invention product 3-3 (Rs1 = 60 μm,
Rs2 = 90 μm, d = 22 μm), the rake angle of the brush with respect to the throw-away tip is set to −10 °, and the film thickness at the edge of the cutting edge is changed by changing the surface treatment time. -6 was prepared. In addition, a sample which was not subjected to any surface treatment was designated as Comparative Product 4-2. Furthermore, a comparative product 4-1 which is out of the range of the present invention, which is subjected to surface treatment by setting the rake angle of the brush with respect to the throw-away tip at 30 °, was prepared. In addition, Rc1 of invention products 4-1 to 4-6 obtained in this manner is 40 μm, 42 μm, 45 μm, 47 μm, and 48 μm, respectively.
m and 50 μm, both in the range of 40 to 50 μm, and Rc1 of the comparative product 4-1 is 100 μm.
m were prepared. In addition, R of invention products 4-1 to 4-6
c2 is 70 μm, 75 μm, 80 μm, and 83 μm, respectively.
m, 86 μm and 90 μm.
Rc2 of the comparison product 4-1.
Was 90 μm.

Table 5 below shows the cutting test results of the comparative product and the invention product.

[0052]

[Table 5]

As can be seen from the test results shown in Table 5,
While the sample of the comparative product 4-2, which was not subjected to the surface treatment, generated initial chipping in the fracture resistance test, the inventive products 4-1 to 4-6 have significantly increased cutting time.
Also, from the results of the wear resistance test, it can be seen that the wear resistance was improved except for the inventive product 4-6. From the above results, it can be seen that the cutting performances of the inventions 4-2 to 4-5 in the range of dx / d = 0.2 to 0.8 are particularly excellent. Above all, invention products 4-3 to 4-5 in the range of dx / d = 0.2 to 0.6 show particularly excellent fracture resistance.

Example 4 Rs1 and Rs2 at the cutting edge ridge portion of the ISO-K10 class base material of the model number SNMG120408 were 30 μm and 30 μm, respectively.
m is coated with the same ceramic film (d = 10 μm) as in Example 1 and then subjected to a surface treatment to obtain a comparative product 5-1 and 5-c having different Rc1 and Rc2. 2. Invention products 5-1 to 5-5 were prepared.
Using these throw-away chips, FCD450
The work material 11 was cut under the following conditions, the fracture resistance of each sample was evaluated, and the wear resistance was evaluated using the FCD700 work material 11 under the following conditions. The reason why ductile cast iron was used in these tests was that a K10 grade base material was used.

Fracture resistance test 2 Cutting speed 150 m / min Feed 0.2-0.4 mm / rev Cutting depth 2 mm Cutting oil Yes The life time is the time from the start of cutting to the time of chipping, and the average of four corners in each sample. The life time was defined as the life time of the sample.

Abrasion resistance test 2 Cutting speed 200 m / min Feeding 0.3 mm / rev Cutting depth 1.5 mm Cutting time 10 minutes Cutting oil Yes The results of these cutting tests are shown in Table 6 below.

[0057]

[Table 6]

As can be seen from the results shown in Table 6, the invention products 5-1 to 5-5 are superior in both the fracture resistance and the abrasion resistance as compared with the comparative products 5-1 and 5-2.
Invention products 5-2 to 5 wherein / Rc1 is in the range of 2.0 to 50.
-4 indicates particularly excellent cutting performance.

Example 5 A comparative product 6-1 (R) having the same base material and the same coating layer as the inventive product 3-2 prepared in Example 3 and having not been subjected to a surface treatment.
(s1 = 60 μm, Rs2 = 90 μm, d = 16 μm)
Using an elastic grindstone to which # 400 SiC abrasive grains adhere, the rotation speed, hardness, and pressing force were selected, and comparative products 6-2 and invention products 6-1 to 6-5 shown in Table 7 below were selected. Was prepared. The same cutting test as in Example 1 was performed, and the results were shown in Table 7 below.
Shown in

[0060]

[Table 7]

As can be seen from the results in Table 7, the invention product 6-
Nos. 1 to 6-5 show superior cutting performance as compared with the comparative products 6-1 and 6-2. Above all, a / b is 1.5-4.
Invention products 6-1 to 6-4 in the range of 0 show particularly excellent cutting performance.

Example 6 Inventive products 6-1 to 6-5 prepared in Example 5 and evaluation product 6-
1 and high-carbon steel SCM435 where the cutting temperature tends to rise
A cutting test was performed under the following conditions using a work piece of a round bar consisting of:

Abrasion resistance test 3 Cutting speed 180 m / min Feed 0.3 mm / rev Cutting depth 1.5 mm Cutting time 10 minutes Cutting oil None As a result of this test, as shown in Table 8 below, the comparative product 6
No. 1 has a large amount of wear, but was able to cut for 10 minutes, whereas inventions 6-3 to 6-5 generated sparks during cutting,
It became impossible to continue cutting. The cause is presumed to be that the alumina film at the cutting edge ridge was removed by the surface treatment after coating.

Therefore, the coating film is formed in order of 0.5 μm from the lower layer.
TiN / 2μmAl ₂ O ₃ /13μmTiCN/0.5
Inventive products 6-1 to 6-6 were formed as four coating layers of μm TiN (total film thickness d = 16 μm) and coated with an alumina film as a lower layer so that the alumina film after the surface treatment remained at the cutting edge ridge. −
Rs1, Rs2 (Rs1 = 60 μm)
m, Rs2 = 90 μm), and the same Rc1, Rc2, a, b (Rc1 = 4) as the invention product 6-4.
5 μm, Rc2 = 120 μm, a = 0.26 mm, b =
Inventive product 7 which has been subjected to a surface treatment so as to be 0.07 mm).
-1 was prepared. As a result of the abrasion resistance test 3 described above, it was found that excellent abrasion resistance shown in Table 8 below was exhibited.

[0065]

[Table 8]

From the results shown in Table 8, it can be seen that, during the surface treatment of the present invention, the throwaway insert having a coating structure in which the oxide film remains on the cutting edge ridge even after the surface treatment has a high carbon content at which the cutting temperature tends to rise. It can be seen that particularly excellent cutting performance is exhibited in high-speed cutting of steel.

Example 7 Inventive products 8-1 to 8-5 were prepared by surface-treating a comparative product 1-1 which had not been subjected to a surface treatment using elastic wheels to which SiC abrasive grains of # 800 and 1200 were attached. . In addition, Rs1, Rs2, Rc of these throw-away chips
1, Rc2, a, b, and d are 60 μm and 90 μm, respectively.
m, 40 μm, 90 μm, 0.15 mm, 0.08 m
m, 10 μm, which are almost the same as Inventions 1-4.
Next, a sample of invention product 1-4 (increased surface area ratio of cutting edge ridge portion of 1.5%) used in example 1 and invention products 8-1 to 8-
The sample No. 5 (increased surface area ratio: 0.2 to 1.3%) and the comparative product 1-1 (increased surface area ratio: 2.4%) are compared.
The measurement of the increased surface area ratio is performed by Elionix Co., Ltd.
ix) Using an ERA8000 type measuring instrument, the measurement magnification was 5000 times in order to measure fine irregularities while eliminating the undulation of the surface of the hard alloy substrate, and the number of samplings in the horizontal and vertical directions within the measurement visual field was measured. 280 points and 2 respectively
10 points were given.

Using these throw-away chips,
The work material 11 made of the die steel SKD61 in which welding easily occurs and having the cross-sectional shape shown in FIG. 5 was cut intermittently under the following conditions, and the peel resistance of each sample was evaluated.

Peeling resistance test 1 Cutting speed 100 m / min Feed 0.15 mm / rev Depth of cut 1.5 mm Cutting oil None In this test, the work material adheres to the cutting edge of the sample from the start of cutting, and film peeling occurs. Up to the life time. The test results are shown in Table 9 below.

[0070]

[Table 9]

From the test results shown in Table 9, it can be seen that the throw-away tips having the increased surface area ratio in the range of 0.1 to 1.3% have excellent peeling resistance. Among them,
Invention products 8-1, 8-2, 8-4, and 8-5 having the increased surface area ratio in the range of 0.2 to 1.0% show particularly excellent peeling resistance.

The embodiments and examples of the present invention disclosed above are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is defined by the appended claims in the above description, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a form of a cutting edge treatment part of a hard alloy base material and a form of a surface treatment part of a coating film in a cutting edge ridge portion of a coated hard alloy tool of the present invention.

FIG. 2 is a perspective view showing a form of a throw-away tip used for verifying the effect of the present invention.

FIG. 3 is a diagram for explaining crater wear generated on a contact surface between a chip and a rake face of a throw-away tip during a cutting test.

FIG. 4A is a schematic perspective view for explaining a definition of an increased surface area ratio, and FIG. 4B is a diagram for explaining a method for obtaining a surface area of a measurement unit by sampling.

FIG. 5 is a cross-sectional view showing a cross-sectional shape of a work material used for interrupted cutting in a fracture resistance test.

FIG. 6A is a cross-sectional view of a coated hard alloy tool coated with four coating films before the coating film is surface-treated.
(B) is a cross-sectional view showing a state in which the oxide ceramic layer remains over the entire cutting edge ridge after the surface treatment of the coating film, and (c).
FIG. 3 is a cross-sectional view of a state where an oxide ceramic layer has been removed from a part of a ridge portion of a cutting edge after surface treatment of a coating film.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hard alloy base material 2 Coating film 3 Cutting edge ridge line 4 Flank 6 Rake face

Claims (10)

[Claims] 1. A hard alloy substrate having a cutting edge treatment portion at a cutting edge ridge portion forming a connecting portion between a flank surface and a rake surface, and a coating film coated on a surface of the hard alloy substrate, A coated hard alloy tool having a surface treatment portion at a cutting edge ridge portion of the surface of the coating film, wherein a convex curved surface formed at a boundary between a flank and a cutting edge treatment portion on the surface of the hard alloy base material. The radius of curvature is Rs1, the radius of curvature of a convex surface formed at the boundary between the flank and the surface treatment portion on the surface of the coating film is Rc1, and the average film thickness of the coating film in a region other than the surface treatment portion is Rc1. When d, Rc1
A coated hard alloy tool, wherein a coated film is formed so that /(Rs1+d)<1.0. 2. A radius of curvature of a convex curved surface formed at a boundary between a rake face and a cutting edge processing portion on the surface of the hard alloy base material is Rs2, and a radius of curvature of a rake face and a surface processing portion on the surface of the coating film is 2. The radius of curvature of the convex surface formed at the boundary is Rc
2, Rc2 / (Rs2 + d)> 1.
The coated hard alloy tool according to claim 1, wherein the coating film is formed so as to be 0. 3. The coated hard alloy tool according to claim 1, wherein Rc1 / (Rs1 + d) is formed to be 0.2 or more and 0.8 or less. 4. The coated hard alloy tool according to claim 2, wherein Rc2 / (Rs2 + d) is formed to be 2.0 or more and 5.0 or less. 5. When the thickness of the thinnest portion of the coating film of the hard alloy substrate is 15 μm or more, and the film thickness at the cutting edge ridge portion thinned by the surface treatment is dx, The coated hard alloy tool according to claim 1, wherein dx / d is formed to be 0.2 or more and 0.8 or less. 6. The coated hard alloy tool according to claim 1, wherein Rs2 / Rs1 is formed to be 0.7 or more and 1.3 or less. 7. The coated hard alloy tool according to claim 1, wherein Rc2 / Rc1 is 2.0 or more and 50 or less. 8. Assuming that the width on the rake face side and the width on the flank side of the cutting edge treatment portion on the surface of the coating film are a and b, the ratio a / b is 1.5 or more and 4.0 or less. A coated hard alloy tool according to claim 1, formed as follows. 9. The coating film has a multilayer structure, at least one of which is composed of an oxide ceramic layer, and a part of the thickness of at least one of the oxide ceramic layers covers the entire region of the cutting edge ridge portion. The coated hard alloy tool according to claim 1, wherein a surface treatment is applied so as to remain over the tool. 10. The increased surface area ratio of at least a part of the surface treatment portion on the surface of the coating film is 0.1% or more.
The coated hard alloy tool according to claim 1, which is not more than 3%.