JP2003266210A - Surface coated cemented carbide cutting tool with hard coating layer displaying excellent wear resistance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface coated cemented carbide cutting tool in which a hard coating layer exerts excellent wear resistance. <P>SOLUTION: This surface coated cemented carbide cutting tool with an entire average layer thickness of 12 to 25 μm has a hard coating layer on a cemented carbide surface. The coating layer is constituted by (a) a lower layer, (b) an upper layer, and (c) a surface layer via an intermediate layer. (a) The lower layer is a titanium carbonitride layer of longitudinally long grown crystal structure having an average layer thickness of 6 to 15 μm. (b) The upper layer has an average layer thickness of 3 to 10 μm, and a granular crystal structure and a mixed phase structure whose crystal structure consists of α and κ aluminas, the ratio of both of the aluminas satisfying the formula, Fα/(Fα+Fκ)=0.1 to 0.4, wherein Fα and Fκ represent the totals of peak intensities appearing on the α and κ crystal surfaces, respectively in diffraction patterns of X ray diffraction method. (c) The surface layer is a titanium carbide layer and/or a titanium carbonitride of a compressive stress holding layer having an average layer thickness of 1.5 of 4 μm and a granular crystal structure. Furthermore, the intermediate layer is a titanium nitride having an average layer thickness of 0.1 to 0.6 μm and a granular crystal structure. <P>COPYRIGHT: (C)2003,JPO

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] TECHNICAL FIELD The present invention relates to a hard coating layer comprising:
Demonstrates even better wear resistance, further extending service life
Surface coated cemented carbide cutting tools that enable life
Coated carbide tools). [0002] 2. Description of the Related Art In general, coated carbide tools include various types of steel and steel.
For turning and planing of workpieces such as cast iron
Throwaway used detachably attached to the end
Tips and drills used for drilling the work material
Tools and miniature drills, as well as face milling of the work material
Solid type end used for groove processing, shoulder processing, etc.
Domill, etc.
Removably attached to the solid type end mill
Similarly, a slow-away end mill tool that performs cutting
Which is known. [0003] Generally, the above-mentioned coated carbide tool is used.
A tungsten carbide-based cemented carbide substrate
(A), for example, a normal chemical vapor deposition apparatus
Used, each having a granular crystal structure, Ti carbide
(Hereinafter referred to as TiC) layer, nitride (hereinafter also referred to as TiC).
N) layer, carbonitride (hereinafter referred to as TiCN) layer,
Carbon dioxide (hereinafter, referred to as TiCO) layer and carbonitridation
One or two of the material (hereinafter, referred to as TiCNO) layers
An average layer of 0.5 to 15 μm consisting of multiple layers
Lower layer having a thickness, (b) also using a conventional chemical vapor deposition apparatus
Al oxide used as a high-temperature hard layer having a granular crystal structure
Minium (hereinafter referred to as Al_TwoO_Three), And
An upper layer having an average layer thickness of 0.5 to 15 μm,
Hard coating layer composed of (a) and (b) is formed by vapor deposition
A known coated carbide tool is
It is also used for continuous and interrupted cutting of steel and cast iron.
It is well known. Further, the above Al_TwoO_ThreeIn layers
Has an α-type crystal structure (hereinafter referred to as α-Al_TwoO_ThreeIndicated by
And κ type (hereinafter κ-Al_TwoO_ThreeEtc.)
It is well known that it is put to practical use.
JP-A-6-8010 and JP-A-7-328808
As described in the report, as the lower layer, ordinary chemical
Mixing containing organic carbonitride as reaction gas in vapor deposition equipment
Using gas, chemical vapor at a medium temperature range of 700 to 950 ° C
To form a vertically elongated crystal structure.
Titanium carbonitride layer (hereinafter, referred to as
(indicated by an l-TiCN layer) are also known. [0004] SUMMARY OF THE INVENTION In recent years,
The adoption of FA is remarkable, while saving labor for cutting.
There are strong demands for energy saving, energy saving, and cost reduction.
Along with this, we aim to further improve the wear resistance of cutting tools,
There is a demand for further extending the service life. [0005] Means for Solving the Problems Accordingly, the present inventors have
In view of the above, the hard coating layer has excellent wear resistance
Coated carbide tool that demonstrates high performance and extends the service life
As a result of conducting research to develop (A) Hard coating formed by vapor deposition on the surface of the above-mentioned super-hard substrate
When the lower layer of the layer is a high toughness layer composed of an l-TiCN layer,
In both cases, the upper layer is α-Al_TwoO_ThreeAnd κ-Al_TwoO_ThreeMixed phase
Having a structure, and the α-Al_TwoO_ThreeAnd κ-Al_TwoO_ThreePhase of
Mutual proportions are found in the diffraction pattern obtained by the X-ray diffraction method.
And the sum of the peak intensities appearing on the α-type crystal plane is Fα, κ
When the sum of the peak intensities appearing on the type crystal plane is Fκ, Fα / (Fα + Fκ) = 0.1 to 0.4, Is a high-temperature hard layer that satisfies_TwoO_ThreeSpecific to crystal mixed layer
And the cemented carbide substrate and lower layer, and the lower layer and upper
An intermediate thin layer made of a TiN layer is used as an adhesion layer between the partial layers.
With the intervening, the upper layer Al_TwoO_ThreeTable of mixed crystal layer
The surface, as a surface layer, charcoal having a granular crystal structure
Titanium nitride layer and / or titanium carbonitride layer (hereinafter referred to as Ti
C layer / TiCN layer).
And a hard coating layer of this configuration is deposited on the surface of the super-hard substrate.
In the case of coated carbide tools made of
Al which is the upper layer of the hard coating layer due to high heat_TwoO_ThreeCrystal blend
Κ-Al in laminated layers_TwoO_ThreePhase shrinks from κ to α
Phase transformation accompanied by α-Al_TwoO_Threephase
Phase transformation is promoted by the catalysis of
When. (B) κ-Al in the above upper layer_TwoO_ThreeFor phase transformation
The accompanying volume shrinkage caused the lower l-TiCN layer to:
It can be sufficiently absorbed by the vertically grown crystal structure.
Therefore, internal stress remains in the 1-TiCN layer.
However, the above-mentioned surface layer, ie, TiC layer / TiCN layer
Cannot absorb the volume shrinkage of the upper layer
Therefore, a large compressive internal stress remains in the upper layer.
Swell. (C) Surface layer of the hard coating layer of the above (a) and (b)
Is composed of TiC layer / TiCN layer which keeps compressive internal stress
Coated carbide tools further improve the wear resistance of the cutting edge
And the service life can be further extended. that's all
The research results shown in (a) to (c) were obtained. The present invention has been made based on the above research results.
The surface of the super-hard substrate, 12-25μ
A hard coating layer with a total average layer thickness of
In the coated carbide tool, the hard coating layer
T which is an adhesion layer having an average layer thickness of 0.1 to 0.6 μm
vapor-deposited and formed via an intermediate thin layer consisting of an iN layer,
(A) a high toughness layer having an average layer thickness of 6 to 15 μm
a lower layer made of an l-TiCN layer, and (b) 3 to 10 μm
Average layer thickness and α-Al_TwoO_ThreeAnd κ-Al_TwoO_ThreeMixed phase
Having a structure, and the α-Al_TwoO_ThreeAnd κ-Al_TwoO_ThreePhase of
Mutual proportions appear in the diffraction pattern obtained by the X-ray diffraction method.
And the sum of the peak intensities appearing on the α-type crystal plane is Fα, κ
When the sum of the peak intensities appearing on the type crystal plane is Fκ,
High enough to satisfy Fα / (Fα + Fκ) = 0.1 to 0.4
Al which is a warm hard layer_TwoO_ThreeAn upper layer composed of a crystal mixed layer,
(C) Further, it is formed by vapor deposition directly on the surface of the upper layer.
And a compressive stress holding layer having an average layer thickness of 1.5 to 4 μm.
And a surface layer composed of a TiC layer / TiCN layer.
A coating with a hard coating layer that exhibits excellent wear resistance
It has features in carbide tools. Next, the hard coating of the coated carbide tool of the present invention is described.
Regarding the covering layer, the average layer thickness _TwoO_ThreeCrystal mixed layer
The reason for limiting the mutual ratios as described above will be described. (1) Intermediate thin layer As described above, the TiN layer constituting the intermediate thin layer includes a super-hard substrate.
Between the lower and upper layers and between the lower and upper layers.
Has the effect of improving the mutual adhesion between these two layers.
However, if the average layer thickness is less than 0.1 μm, the desired excellent
Adhesion cannot be ensured, while the average layer thickness is
If the thickness exceeds 0.6 μm, the wear resistance of the hard coating layer is reduced.
This not only causes
Insufficient absorption of volumetric shrinkage due to phase transformation of layer into lower layer
This causes compressive stress to remain in the upper layer itself,
As a result, the upper layer is relatively thick.
Therefore, chipping is likely to occur, so the average layer
The thickness was determined to be 0.1-0.6 μm. (2) Lower layer The l-TiCN layer constituting the lower layer has a high toughness layer
Basically, it improves the toughness of the hard coating layer and
To reduce mechanical and thermal shock,
In addition to significantly suppressing the occurrence of
Absorbs volume shrinkage generated in the upper layer,
Make sure that the compressive stress that causes chipping does not remain.
However, if the average layer thickness is less than 6 μm,
The desired effect cannot be obtained in the above-mentioned operation, while the average layer thickness is 1
If it exceeds 5 μm, the hard coating layer may cause uneven wear.
Plastic deformation tends to occur.
It was determined to be 6 to 15 μm. (3) Upper layer Al constituting upper layer_TwoO_ThreeΑ-Al in the crystal mixed layer
_TwoO_ThreeHas a κ-Al_TwoO_ThreeIs α-Al_TwoO_ThreeBody
Acts to promote phase transformation with product shrinkage
However, as described above, α-type crystal plane in the diffraction pattern, generally
Have (012) plane, (104) plane, (110), and (11) plane.
3) The peaks appearing on the (024) and (116) planes
The sum of the peak strengths is Fα, also the κ type crystal plane, generally
(002) plane, (112) plane, (013) plane, (12) plane
2) The peaks appearing on the (015) plane and the (050) plane
When the sum of the peak strengths is Fκ, Fα / (Fα + F
When the value of κ) is less than 0.1, α-Al_TwoO_ThreePercent
Too small for κ-Al_TwoO_ThreeΑ-Al_TwoO_ThreePhase transformation to
The promoting effect is insufficient, while the Fα / (Fα + F
When the value of κ) exceeds 0.4, relatively phase transformation κ-
Al_TwoO_ThreeIs too low and the desired
Because it becomes difficult to keep the compressive internal stress,
The value of Fα / (Fα + Fκ) is set to 0.1 to 0.4.
Was. Also, α-Al_TwoO_ThreeAnd κ-Al_TwoO_ThreeAny of
Has excellent high-temperature hardness and heat resistance.
As a layer, it gives the hard coating layer hardness and heat resistance.
Without chipping in the coexistence with the lower layer,
It has the effect of exhibiting excellent wear resistance.
If the average layer thickness is less than 3 μm, the desired excellent wear resistance is secured.
On the other hand, the average layer thickness of which exceeds 10 μm
Does the chipping easily occur in the hard coating layer?
Thus, the average layer thickness was determined to be 3 to 10 μm. (4) Surface layer The TiC layer / TiCN layer constituting the surface layer has
Al constituting the upper layer_TwoO_ThreeΚ-A in the crystal mixed layer
l_TwoO_ThreeΑ-Al during cutting_TwoO_ThreeWith the transformation to
High compressive stress will remain due to volume shrinkage,
The surface layer as the compressive stress holding layer is always
Combined with maintaining high compressive stress,
Immediately compared to TiC layer / TiCN layer without compressive stress
It exhibits excellent wear resistance, but its average layer thickness is
If the thickness is less than 1.5 μm, cracks occur due to volume contraction of the upper layer.
The compressive stress generated by the volume shrinkage phenomenon.
Cannot be held sufficiently within the
If it exceeds 4 μm, the phase transformation in the upper layer becomes slow.
As a result, the residual compressive stress in the surface layer is small.
As a result, the desired abrasion resistance improving effect is obtained on the surface layer.
Therefore, the average layer thickness was determined to be 1.5 to 4 μm.
I did. (5) Hard coating layer If the overall average layer thickness is less than 12 μm, the desired excellent
Abrasion cannot be ensured, while the average layer thickness is 2
If it exceeds 5 μm, chipping is likely to occur in the hard coating layer.
The average layer thickness is set to 12 to 25 μm
Was. The coated carbide tool can be easily identified before and after use.
For the purpose, a TiN layer having a golden color tone as the outermost layer
May be deposited with an average layer thickness of 0.1 to 0.5 μm.
No. [0012] DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a coated carbide tool of the present invention
Will be specifically described with reference to examples. As raw material powder,
The deviation also has a predetermined average particle size in the range of 0.5 to 4 μm.
WC powder, TiC powder, TaC powder, NbC powder, C
r_ThreeC_TwoPrepare powder, TiN powder and Co powder
These raw material powders are blended in the composition shown in Table 1 and
Add alcohol with a mil mill, wet mix for 24 hours and dry
After that, it is pressed at a pressure of 150 MPa into a green compact of a predetermined shape.
This compact is pressed in a vacuum of 6 Pa or less at 1370
Under the condition of holding for 1 hour at a predetermined temperature within the range of ~ 1470 ° C
Vacuum sintering and after sintering, R: 0.07
ISO / CNMG120
Super with a throwaway tip shape specified in 408
Hard substrates A to F were respectively manufactured. In addition, the above-mentioned super hard group
The surface portions of the super hard bases C to F in the bodies A to F
Co-rich region (softening) over a depth range of 5-30 μm
Layer) was formed. Next, the surfaces of these superhard substrates A to F
Table 2 (l-Ti in the table)
CN is a vertically elongated growth described in JP-A-6-8010.
The figure shows the conditions for forming a TiCN layer having a crystal structure.
Under the conditions shown in Tables 3 and 4,
And a hard coating layer with the target layer thickness.
Silicon carbide powder is dispersed at the edge of the cutting edge where the flank and flank intersect
By polishing the surface with a urethane resin grindstone
The present invention coated carbide tools 1-12 and comparative coated carbide
Tools 1 to 12 were manufactured respectively. Note that the comparison coating carbide
In each of tools 1 to 12, the upper layer of the hard coating layer was α-Al
_TwoO_ThreeOr κ-Al_TwoO_ThreeAnd the formation of the surface layer
Not something. The resulting coated cemented carbide tools 1 to 1
Composition of hard coating layer of 12 and comparative coated carbide tools and
The layer thickness was measured using an X-ray diffraction device and a scanning electron microscope.
Table 3 and 4 show the composition, target layer thickness and actual
Qualitatively the same composition and average layer thickness (average of measurements at five arbitrary locations)
Value). In addition, the above-mentioned coated cemented carbide
Which is the upper layer constituting the hard coating layer of the tools 1 to 12_Two
O_ThreeThe X-ray diffraction pattern of the mixed crystal layer
(Α) crystal plane (012) plane, (104) plane,
The (110), (113), (024), and (1)
16) Total peak intensity appearing on the surface: Fα, also κ type
(002) plane, (112) plane, and (013) crystal plane
Plane, (122) plane, (015) plane, and (050) plane
Of the peak intensities appearing in the equation:
Calculate the value of Fα / (Fα + Fκ) from
The results are shown in Table 5. Next, the coated carbide tools 1 to 12 according to the present invention will be described.
And the comparative coated carbide tools 1 to 12
Screwed to the end of a steel cutting tool with a fixing jig
so, Work material: JIS SCM440 round bar, Cutting speed: 420 m / min. , Cut: 1.5 mm, Feed: 0.3 mm / rev. , Cutting time: 5 minutes, Dry continuous cutting test of alloy steel under the conditions of Work material: JIS S20C with 4 longitudinal grooves at regular intervals in the length direction
Round bar, Cutting speed: 330 m / min. , Notch: 2.0 mm, Feed: 0.2 mm / rev. , Cutting time: 5 minutes, Intermittent cutting test of carbon steel under the conditions of Work material: JIS FCD450 round bar, Cutting speed: 150 m / min. , Notch: 2.0 mm, Feed: 0.25 mm / rev. , Cutting time: 2 minutes, A dry continuous cutting test of spheroidal graphite cast iron was conducted under the following conditions.
The flank wear width of the cutting edge was also measured in the displacement cutting test. This
Table 5 shows the measurement results. [0016] [Table 1][0017] [Table 2] [0018] [Table 3][0019] [Table 4] [0020] [Table 5][0021] From the results shown in Tables 3 to 5, it can be seen that the present invention
Coated carbide tools 1 to 12 constitute the surface layer of the hard coating layer
Al as an upper layer is added to the TiC layer / TiCN layer._TwoO_ThreeCrystal blend
Κ-Al in laminated layers_TwoO_ThreeΑ-Al during cutting_Two
O_ThreeHigh compressive stress due to volume shrinkage accompanying phase transformation to
It will remain, and the surface as this compressive stress holding layer will
The layer will always retain a high compressive stress during the cutting operation.
In combination with the above, the surface layer TiC layer / TiC
No N layer and upper layer is α-Al_TwoO_ThreeLayer or κ
-Al_TwoO_ThreeCompared to the coated carbide tools 1 to 12 consisting of layers
It is clear that they exhibit excellent wear resistance.
As described above, the coated carbide tool of the present invention can be used for various steels and
Excellent wear resistance in continuous and intermittent cutting of cast iron
Demonstrates further cutting and labor savings in cutting
It is possible to further reduce the cost.

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Fumio Tsushima             1511 Furamagi, Ishishita-cho, Yuki-gun, Ibaraki Prefecture             Mitsubishi Materials Corporation Tsukuba Works (72) Inventor Kazuhiro Kono             1511 Furamagi, Ishishita-cho, Yuki-gun, Ibaraki Prefecture             Mitsubishi Materials Corporation Tsukuba Works (72) Inventor Yoko Watanabe             1511 Furamagi, Ishishita-cho, Yuki-gun, Ibaraki Prefecture             Mitsubishi Materials Corporation Tsukuba Works F term (reference) 3C046 FF03 FF10 FF13                 4K030 AA03 AA09 AA14 AA17 AA18                       AA24 BA18 BA36 BA38 BA41                       BA43 BB03 BB12 CA03 JA01                       LA22

Claims (1)

Claims: 1. A surface-coated cemented carbide cutting tool comprising a tungsten carbide-based cemented carbide substrate and a hard coating layer having a total average layer thickness of 12 to 25 μm formed on the surface of the substrate. The hard coating layer was formed by vapor deposition through an intermediate thin layer consisting of a titanium nitride layer, which is an adhesion layer having an average layer thickness of 0.1 to 0.6 μm and a granular crystal structure, (a) 6 A lower layer comprising a titanium carbonitride layer which is a tough layer having an average layer thickness of about 15 μm and a vertically elongated crystal structure, and (b) an average layer thickness of 3 to 10 μm and a granular crystal structure, and having a crystal structure. It has a mixed phase structure composed of α-type and κ-type aluminum oxides, and the mutual proportion of the α-type aluminum oxide and κ-type aluminum oxide appears on the α-type crystal plane in the diffraction pattern obtained by the X-ray diffraction method. Where Fα is the total peak intensity and Fκ is the total peak intensity appearing on the κ-type crystal plane, and a mixture of aluminum oxide crystals as a high-temperature hard layer satisfying the following condition: Fα / (Fα + Fκ) = 0.1 to 0.4. (C) a titanium carbide layer, which is a compressive stress holding layer having an average layer thickness of 1.5 to 4 μm and a granular crystal structure, which is directly formed on the surface of the upper layer by vapor deposition, and / or Or a surface-coated cemented carbide cutting tool having a hard coating layer exhibiting excellent wear resistance, comprising a surface layer comprising a titanium carbonitride layer.