JP5935479B2 - Surface-coated cutting tool with excellent chipping resistance with a hard coating layer in high-speed milling and high-speed intermittent cutting - Google Patents

Description

  This invention is a surface that exhibits high chipping resistance with a hard coating layer in high-speed milling cutting and high-speed intermittent cutting in which an impact load is applied to the cutting edge while generating high heat in alloy steel and the like. The present invention relates to a coated cutting tool (hereinafter referred to as a coated tool).

Conventionally, generally composed of tungsten carbide (hereinafter referred to as WC) based cemented carbide, titanium carbonitride (hereinafter referred to as TiCN) based cermet or cubic boron nitride (hereinafter referred to as cBN) based ultra high pressure sintered body There is known a coated tool in which a Ti—Al based composite nitride layer is formed by physical vapor deposition on a surface of a substrate (hereinafter collectively referred to as a substrate) as a hard coating layer. It is known that it exhibits excellent wear resistance.
However, although the above-mentioned conventional coated tool coated with a Ti-Al composite nitride layer is relatively excellent in wear resistance, it tends to cause abnormal wear such as chipping when used under high-speed milling cutting conditions. Therefore, various proposals for improving the hard coating layer have been made.

For example, Patent Document 1 satisfies 0.35 ≦ X ≦ 0.60 (where X is an atomic ratio) when expressed on the surface of a substrate by a composition formula: (Ti _1-X Al _X ) N. A hard coating layer made of a composite nitride of Ti and Al is formed by physical vapor deposition, and the hard coating layer has a granular crystal structure with an average particle size of 30 nm or less, and a columnar crystal structure with an average particle size of 50 to 500 nm. It has been proposed that it be constructed as an alternating layered structure, and this makes it possible for the hard coating layer to exhibit excellent chipping resistance, fracture resistance, and peeling resistance in high-speed intermittent cutting of high-hardness steel. Yes.
However, since this coated tool deposits a hard coating layer by physical vapor deposition, the Al content ratio X cannot be increased to 0.6 or more, and it is desired to further improve the cutting performance.

From such a viewpoint, a technique for increasing the Al content ratio X to about 0.9 by forming a hard coating layer by chemical vapor deposition has also been proposed.
For example, Patent Document 2 discloses that the value of the Al content ratio X is 0.65 to 0.65 by performing chemical vapor deposition in a temperature range of 650 to 900 ° C. in a mixed reaction gas of TiCl ₄ , AlCl ₃ , and NH _3. Although it is described that a (Ti _1-X Al _X ) N layer of 0.95 can be formed by vapor deposition, in this document, an Al ₂ O ₃ layer is further formed on the (Ti _1-X Al _X ) N layer. Therefore, the cutting performance is improved by forming the (Ti _1-X Al _X ) N layer in which the value of X is increased from 0.65 to 0.95. There is no disclosure up to the point of how this will be affected.

Further, for example, Patent Document 3 discloses that Al is contained by performing chemical vapor deposition without using plasma at a temperature of 700 to 900 ° C. in a mixed reaction gas of TiCl ₄ , AlCl ₃ , NH ₃ , and N ₂ H _4. It is described that a hard coating layer composed of a cubic (Ti _1-X Al _X ) N layer having a ratio X value of 0.75 to 0.93 can be formed by vapor deposition. There is no disclosure of applicability as a tool.

JP2011-224715A Special table 2011-516722 gazette US Pat. No. 7,767,320

In recent years, the performance of cutting machines has been remarkable. On the other hand, there is a strong demand for labor saving and energy saving and further cost reduction for cutting work.Accordingly, cutting has become a trend toward higher speed and higher efficiency. The coated tool is further required to have abnormal damage resistance such as chipping resistance, chipping resistance, and peel resistance, and excellent wear resistance over a long period of use.
However, in the coated tool described in Patent Document 1, a hard coating layer made of a (Ti _1-X Al _X ) N layer is deposited by physical vapor deposition to increase the Al content X in the hard coating layer. Therefore, for example, when it is subjected to high-speed milling cutting of alloy steel, it cannot be said that the chipping resistance is sufficient.
On the other hand, for the (Ti _1-X Al _X ) N layer formed by the chemical vapor deposition method described in Patent Documents 2 and 3, the Al content X can be increased and a cubic structure is formed. Therefore, although a hard coating layer having a predetermined hardness and excellent wear resistance can be obtained, the adhesion strength to the substrate is not sufficient and the toughness is inferior. When used as a coated tool for cutting, abnormal damage such as chipping, chipping and peeling tends to occur, and it cannot be said that satisfactory cutting performance is exhibited.
The present invention provides a coated tool that exhibits excellent chipping resistance and excellent wear resistance over a long period of use even when subjected to high-speed milling cutting of alloy steel, etc. It is intended.

From the above-mentioned viewpoint, the present inventors have developed a composite carbonitride of Ti and Al (hereinafter, “(Ti, Al) (C, N)” or “(Ti _1-X Al _X ) (C _Y N _{1- 1 Y)} "is sometimes indicated by) hard layer chipping resistance of the coated tool coated formed by chemical vapor deposition consisting of, in order improve the abrasion resistance, the results of extensive studies, the following findings Obtained.

Tungsten carbide-based cemented carbide (hereinafter referred to as “WC-based cemented carbide”), titanium carbonitride-based cermet (hereinafter referred to as “TiCN-based cermet”), or cubic boron nitride-based ultrahigh pressure sintered body (hereinafter referred to as “TiCN-based cemented carbide”) On the surface of the substrate composed of any one of “cBN-based ultra-high pressure sintered body”
For example, by chemical vapor deposition which comprises, as a reaction gas component trimethyl aluminum _{(Al (CH 3) 3)} , as a hard coating _{layer, (Ti 1-X Al X} ) of the cubic structure (C _{Y N 1-Y)} layer Depending on the composition, it has a composition gradient structure in which the Al content in the hard coating layer gradually increases from the interface between the hard coating layer and the substrate toward the surface of the hard coating layer. Further, strain due to the difference in lattice constant of (Ti _1-X Al _X ) (C _Y N _1-Y ) was positively introduced, and on the interface side between the hard coating layer and the substrate, the average aspect ratio _AL was 1-2 in which granular structure formed, on the other hand, in the surface layer of the hard coating layer, by forming the columnar texture average aspect ratio _{a H} is _{3~10, (Ti 1-X Al} X) (C _Y N _1- It was found that) the chipping resistance of the hard coating layer consisting of layers is improved.

In the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer, X and Y are atomic ratios, and 0.55 ≦ X ≦ 0.95, 0.0005 ≦ Y ≦ Since 0.005 is satisfied, the cubic structure is maintained up to a high Al content ratio X (for example, X = 0.80 to 0.95) that cannot be formed by vapor deposition by the conventional PVD method (Ti, It can be seen that the Al) (C, N) layer was preferably formed by chemical vapor deposition containing trimethylaluminum (Al (CH ₃ ) ₃ ) as a reactive gas component.

Further, the present inventors have, when by chemical vapor deposition of the present invention was deposited forming a _{(Ti 1-X Al X)} (C Y N 1-Y) layer of the cubic structure, a trace amount in the layer Although chlorine is contained, if the average chlorine content is 1 atomic% or less, the hard coating layer will not be embrittled and will not adversely affect the properties of the hard coating layer. When having a composition gradient structure in which the average chlorine content gradually decreases from the interface toward the surface side of the hard coating layer, the hard coating layer not only has lubricity but also improves chipping resistance. I found it.

  Therefore, when the coated tool provided with the hard coating layer as described above is used for, for example, high-speed milling cutting and high-speed intermittent cutting of alloy steel, the occurrence of chipping, chipping, peeling, etc. can be suppressed, and long-term Therefore, it is possible to exhibit excellent wear resistance throughout the use.

This invention was made based on the above research results,
“(1) On the surface of a substrate composed of either a tungsten carbide-based cemented carbide, a titanium carbonitride-based cermet, or a cubic boron nitride-based ultrahigh-pressure sintered body,
(A) a hard coat layer of a composite carbonitride layer of Ti and Al on cubic flat HitoshisoAtsu 2~20μm are the made form,
(B) The hard coating layer has an average composition,
_{Formula: (Ti 1-X Al X} ) (C Y N 1-Y)
In this case, the Al content ratio X and the C content ratio Y (where X and Y are atomic ratios) satisfy 0.55 ≦ X ≦ 0.95 and 0.0005 ≦ Y ≦ 0.005, respectively. Satisfied,
(C) From the interface between the hard coating layer and the substrate, composition analysis is performed centering on the position L entering the inside of the 0.5 μm hard coating layer, and the Al content of the composite carbonitride of Ti and Al having a cubic structure When the ratio is obtained and the average value is X _L (however, the atomic ratio), the Al content ratio X _L is 0.55 ≦ X _L ≦ 0.70, and is 0 from the surface layer of the hard coating layer. The composition analysis is performed centering on the position H inside the hard coating layer of 5 μm, the Al content ratio of the composite carbonitride of Ti and Al having a cubic structure is obtained, and the average value is calculated as X _H (however, the atomic ratio ), The Al content ratio X _H is 0.80 ≦ X _H ≦ 0.95, and the Al content ratio in the hard coating layer is determined from the interface side between the hard coating layer and the substrate. It has a composition gradient structure that gradually increases toward the surface side of
(D) From the interface between the hard coating layer and the substrate, the long axis width of each of the composite carbonitride crystal grains of Ti and Al having a cubic structure existing at a position L entering the inside of the 0.5 μm hard coating layer, seeking short axis width and the ratio of the long axis width and the width of the short axis of their crystal grains and an average aspect ratio a _L, the average aspect ratio a _L is 1 to 2, also the surface layer of the hard coating layer The long axis width and the short axis width are obtained for each of the Ti and Al composite carbonitride crystal grains having a cubic structure existing at the position H inside the 0.5 μm hard coating layer. and when the ratio of the width of the short axis and an average aspect ratio a _H, the surface-coated cutting tool, wherein the average aspect ratio a _H is 3-10.
(2) The surface-coated cutting tool according to (1) above, wherein the average chlorine content contained in the hard coating layer is 0.001 to 1.0 atomic%.
(3) From the interface between the hard coating layer and the substrate, composition analysis is performed centering on the position L entering the inside of the 0.5 μm hard coating layer to determine the chlorine content, and the average value is the average chlorine content. When C _L, the average chlorine content _{C L} is 0.02 to 1.0 atomic%, and, from the surface layer of the hard coating layer, around a position H that has entered the interior of 0.5μm hard layer perform composition analysis, determine the content of chlorine, when the average value and the average chlorine content _{C H,} the average chlorine content _{C H} is 0.001 to 0.01 atomic%, further, a hard coating layer (2) characterized in that the average chlorine content therein has a composition gradient structure that gradually decreases from the interface side between the hard coating layer and the substrate toward the surface layer side of the hard coating layer. The surface-coated cutting tool described.
(4) The hard coating layer is at least surface-coated cutting tool according to any one of (1) to (3), characterized in that the vapor deposited by chemical vapor deposition containing trimethyl aluminum as a reaction gas component Manufacturing method . "
It has the characteristics.

  Next, the hard coating layer of the coated tool of the present invention will be described more specifically.

The average composition of the cubic composite carbonitride layer of Ti and _{Al ((Ti 1-X Al} X) (C Y N 1-Y) layer):
In the above (Ti _1-X Al _X ) (C _Y N _1-Y ) layer, if the Al content ratio X (atomic ratio) is less than 0.55, the high temperature hardness is insufficient and the wear resistance is reduced. On the other hand, if the value of X (atomic ratio) exceeds 0.95, the cubic structure cannot be maintained due to the decrease in the relative Ti content, so the high-temperature strength decreases, chipping, and defects Therefore, the value of X (atomic ratio) needs to be 0.55 or more and 0.95 or less.
When the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer having the above composition is formed by vapor deposition by the PVD method, the crystal structure is a hexagonal crystal. (Ti _1-X Al _X ) having the above composition while maintaining the cubic structure up to the range of the high Al content ratio X (for example, X = 0.80 to 0.95). Since a (C _Y N _1-Y ) layer can be obtained, there is no decrease in film hardness.
Further, in the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer, the C component improves the layer hardness, while the N component has an effect of improving the high-temperature strength of the layer. However, when the content ratio Y (atomic ratio) of the C component is less than 0.0005, high hardness cannot be obtained. On the other hand, when Y (atomic ratio) exceeds 0.005, the high-temperature strength decreases. , Y (atomic ratio) was set to 0.0005 or more and 0.005 or less.
The (Ti _1-X Al _X ) (C _Y N _1-Y ) layer has an average layer thickness of less than 2 μm, and cannot sufficiently ensure adhesion to the substrate, whereas the average layer When the thickness exceeds 20 μm, it becomes easy to cause thermoplastic deformation by high-speed milling with high heat generation, which causes uneven wear. Therefore, the total average layer thickness is set to 2 to 20 μm.

In the present invention, in the (Ti _1-X Al _X ) (C _Y N _1-Y ) layer having the above average composition, it is not a uniform composition over the entire layer, but from the interface side of the hard coating layer with the substrate, A composition gradient structure in which the Al content in the hard coating layer continuously increases toward the surface layer side of the hard coating layer is formed.
That is, compositional analysis is performed from the interface between the substrate surface and the hard coating layer, centering on the position L on the interface side with the substrate entering the inside of the 0.5 μm hard coating layer, and a composite carbonitriding of Ti and Al having a cubic structure The Al content ratio X _L (atomic ratio) of the product is 0.55 or more and 0.70 or less, and from the surface of the hard coating layer, centering on the position H of the surface layer portion that enters the 0.5 μm hard coating layer The composition analysis is performed, the Al content ratio X _H (atomic ratio) of the composite carbonitride of Ti and Al having a cubic structure is 0.80 or more and 0.95 or less, and from the interface side with the substrate of the hard coating layer, An Al composition gradient structure in which the Al content rate gradually increases toward the surface layer side of the hard coating layer is formed.
By such a composition gradient structure, lattice strain due to the difference in crystal lattice constant depending on the composition is introduced into the hard coating layer toward the surface layer side. As a result, the chipping resistance of the hard coating layer is improved. improves.

In the present invention, the structure of the (Ti _1-X Al _X ) (C _Y N _1-Y ) crystal grains constituting the hard coating layer has a granular structure in the hard coating layer on the interface side with the substrate, A columnar structure is formed on the surface side of the hard coating layer.
That is, from the interface between the substrate surface and the hard coating layer, an average aspect A _L of the crystal grains at the position L of the interface with the inside containing substrates of 0.5μm hard layer and granular structure is 1-2, also , from the surface of the hard coating layer, an average aspect a _H of the crystal grains at the position H of the surface layer portion which has entered the interior of 0.5μm hard layer and columnar tissue from 3 to 10.
In the present invention, by forming the above-described structure, the adhesion of the hard coating layer can be improved on the interface side with the substrate, and the hard coating layer on the surface layer side has excellent wear resistance. At the same time, since the structure is different between the interface side with the substrate and the surface layer side, it has excellent chipping resistance in order to prevent crack propagation from the surface layer side.

In the present invention, a (Ti _1-X Al _X ) (C _Y N _1-Y ) layer is formed by vapor deposition by a chemical vapor deposition method as described later. At this time, chlorine, which is a reactive gas component, is contained in the layer. Contained.
Chlorine contained in the layer causes embrittlement of the layer itself when it is in a large amount (amount exceeding 1 atomic%), but only if it is contained in a trace amount in the range of 0.001 atomic% to 1 atomic%. Since the lubricity can be improved without lowering the toughness of the layer, it is desirable to contain chlorine having an average chlorine content of 0.001 atomic% to 1 atomic% in the layer.
Further, when chlorine is contained in the layer, a composition gradient structure in which the average chlorine content gradually decreases from the interface side between the hard coating layer and the substrate toward the surface layer side of the hard coating layer is formed. Can improve lubricity without causing a reduction in chipping resistance of the hard coating layer.
Specifically, from the interface between the substrate surface and the hard coating layer, composition analysis is performed centering on the position L entering the inside of the 0.5 μm hard coating layer, the chlorine content is determined, and the average value is the average chlorine content center when the amount _{C L,} the average chlorine content _{C L} is 0.02 to 1.0 atomic%, and the surface of the hard coating layer, the position H which has entered the interior of 0.5μm hard layer The chlorine content is determined, and the average value is defined as the average chlorine content C _{H. The} average chlorine content C _H is 0.001 to 0.01 atomic%, and the hard coating layer By forming a composition gradient structure in which the average chlorine content gradually decreases toward the surface layer side, the lubricity and chipping resistance of the hard coating layer can be enhanced.

The (Ti _1-X Al _X ) (C _Y N _1-Y ) layer of the present invention can be deposited by, for example, a thermal CVD method under the following conditions.
Reaction gas composition (volume%):
TiCl ₄ 2.6 to 5.0%, Al (CH ₃ ) _{3 0 to} 10.0%,
AlCl _{3 0 to} 10.0%, NH ₃ 6.0 to 10.0%,
_{N 2 6.0~10.0%, C 2 H} 4 0~1.0%,
Ar 6.0 to 10.0%, remaining H ₂ (However, neither Al (CH ₃ ) ₃ nor AlCl ₃ becomes 0% at the same time.)
Reaction atmosphere temperature: 700 to 900 ° C.
Reaction atmosphere pressure: 2 to 10 kPa,
By the thermal CVD method under the above conditions, the average composition satisfies 0.55 ≦ X ≦ 0.95, 0.0005 ≦ Y ≦ 0.005 (where X and Y are atomic ratios),
_{Formula: (Ti 1-X Al X} ) (C Y N 1-Y)
A cubic composite carbonitride layer of Ti and Al expressed by

Gradually increases with the above chemical vapor deposition (thermal CVD method) by depositing form _{(Ti 1-X Al X)} (C Y N 1-Y) layer, Al content is, toward the surface layer side of the hard coating layer In addition, the Al content ratio X _L (atomic ratio) at the position L of the hard coating layer satisfies 0.55 ≦ X _L ≦ 0.70, and the Al content ratio X _H (atomic ratio) at the position H However, in the composition gradient structure satisfying 0.80 ≦ X _H ≦ 0.95, for example, the amount of trimethylaluminum (Al (CH ₃ ) ₃ ), which is the reaction gas component, is adjusted with the progress of vapor deposition ( In other words, it is possible to perform vapor deposition by increasing the amount of AlCl ₃ component and relatively decreasing the amount of Ar gas added with the progress of vapor deposition.

In addition, with respect to the structure of crystal grains, as with the composition gradient structure of Al, for example, the amount of the reaction gas component trimethylaluminum (Al (CH ₃ ) ₃ ) increased with the progress of vapor deposition, As the N ₂ gas is added, the amount of N ₂ gas added is relatively large and a small amount of C ₂ H ₄ gas is added from the middle of the vapor deposition, so that crystals having an average aspect ratio of 1 to 2 on the interface side between the hard coating layer and the substrate On the other hand, crystal grains having an average aspect ratio of 3 to 10 can be formed on the surface layer side of the hard coating layer.

Furthermore, according to the chemical vapor deposition method (thermal CVD method), the amount of the reaction gas component trimethylaluminum (Al (CH ₃ ) ₃ ) is increased with the progress of the vapor deposition formation, so that the reaction gas component AlCl _{3 is} relatively increased. the amount of decrease is vapor deposited _{(Ti 1-X Al X)} (C Y N 1-Y) average chlorine content in the layer gradually decreases composition gradient toward the surface layer side of the hard coating layer A structure is formed.
Thus, for example, the amount of reaction gas component trimethylaluminum (Al (CH ₃ ) ₃ ) is adjusted according to the desired X value, aspect ratio, average chlorine content, etc., along with the desired composition gradient (Al, chlorine). By doing so, it is possible to obtain a desired hard coating layer.

Coated tool of the present invention, by chemical vapor deposition, as a hard coating layer, cubic _{(Ti 1-X Al X)} (C Y N 1-Y) layer of crystal structure is deposited formed, rigid coating layer, the hard From the interface between the coating layer and the substrate, it has a composition gradient structure in which the Al content rate gradually increases as it goes to the surface layer side of the hard coating layer, and different structure forms are formed on the interface side and the surface layer side, In addition, it has a composition gradient structure that gradually decreases the average chlorine content, providing excellent adhesion, lubricity, chipping resistance, and wear resistance, and high-speed milling cutting of alloy steel and high-speed intermittent cutting of hardened steel. Even when it is used for the above, excellent cutting performance can be exhibited over a long period of use.

The schematic explanatory drawing of the hard coating layer longitudinal cross-section of this invention coated tool is shown.

  Next, the coated tool of the present invention will be specifically described with reference to examples.

As raw material powders, WC powder, TiC powder, ZrC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, and Co powder all having an average particle diameter of 1 to 3 μm were prepared. Then, after adding wax, ball mill mixing in acetone for 24 hours, drying under reduced pressure, press-molding into a green compact of a predetermined shape at a pressure of 98 MPa. Substrate made of WC-base cemented carbide having an insert shape defined in ISO standard / SEEN1203AFSN1 after vacuum sintering in vacuum at a predetermined temperature within a range of 1370 to 1470 ° C. for 1 hour. A to D were produced.

In addition, as raw material powders, TiCN (mass ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder, all having an average particle diameter of 0.5 to 2 μm. Co powder and Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 2, wet mixed by a ball mill for 24 hours, dried, and pressed into a compact at a pressure of 98 MPa. The green compact was sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1540 ° C. for 1 hour, and after sintering, a base body made of TiCN base cermet having an ISO standard / SEEN1203AFTN1 insert shape a -D were produced.

Next, on the surfaces of the tool bases A to D and the tool bases a to d, (Ti _1-X Al _X ) (C _Y ) of the present invention is used under the conditions shown in Table 3 using a normal chemical vapor deposition apparatus. The present invention coated tools 1 to 10 shown in Table 5 were manufactured by vapor-depositing N _{1 -Y} ) layers at a target layer thickness.

Further, for the purpose of comparison, an ordinary chemical vapor deposition apparatus was used on the surfaces of the tool bases A to D and the tool bases a to d, and under the conditions shown in Table 4, (Ti _1-x Al _x ) of the comparative example. Comparative example-coated tools 1 to 8 shown in Table 6 were manufactured by vapor-depositing (C _y N _1-y ) with a target layer thickness.

For reference, (Ti _1-x Al _x ) (C _y N _1-y ) of the reference example is applied to the surfaces of the tool base A and the tool base a by arc ion plating using a conventional physical vapor deposition apparatus. Reference example coated tools 9 and 10 shown in Table 6 were manufactured by vapor deposition with a target layer thickness.
The conditions for arc ion plating are as follows.
(A) The tool bases A and a are ultrasonically cleaned in acetone and dried, and in the outer peripheral portion at a predetermined distance in the radial direction from the central axis on the rotary table in the arc ion plating apparatus. Along with this, an Al-Ti alloy having a predetermined composition is arranged as a cathode electrode (evaporation source),
(B) First, the inside of the apparatus is heated to 500 ° C. with a heater while the inside of the apparatus is evacuated and kept at a vacuum of 0.1 Pa or less, and then the tool base that rotates while rotating on the rotary table is −1000 V. A DC bias voltage is applied, and an arc discharge is generated by flowing a current of 100 A between the cathode electrode and the anode electrode made of an Al—Ti alloy, and the tool base surface is bombard washed.
(C) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 4 Pa, a DC bias voltage of −100 V is applied to the tool base that rotates while rotating on the rotary table, and A current of 120 A is passed between the cathode electrode (evaporation source) made of the Al—Ti alloy and the anode electrode to generate arc discharge, and the target average composition and target shown in Table 6 are formed on the surface of the tool base. A cover layer composed of an (Al, Ti) N layer having an average layer thickness is formed by vapor deposition.
Comparative surface-coated inserts (hereinafter referred to as comparative coated inserts) 9 to 10 as comparative coated tools were produced.

Next, for the hard coating layers of the above-described inventive coated tools 1 to 10, the average Al content ratio X, the average C content ratio Y, the Al content ratios X _L and X _H , and the average aspect ratios A _L and A of the hard coating layer. _H , average chlorine content, average chlorine content C _L , and average chlorine content C _H were measured.
The specific measurement is as follows.
Using a fluorescent X-ray analyzer, the surface of the hard coating layer is irradiated with X-rays having a spot diameter of 100 μm, and the average Al content ratio X, average C content ratio Y and average chlorine content are determined from the analysis results of the characteristic X-rays obtained. Asked.
Next, a cross section perpendicular to the surface of the substrate was created using a diamond polishing machine, and a position L that entered the 0.5 μm hard coating layer from the interface between the hard coating layer and the substrate was spotted using an electron beam microanalyzer device. Irradiate an electron beam with a spot diameter of 0.4 μm at the center of the substrate, that is, 0.7 μm hard coating layer from the position entering the inside of the 0.3 μm hard coating layer from the interface between the hard coating layer and the substrate centering on the position L. The electron beam was irradiated up to the position inside, and the Al content ratio _XL and the average chlorine content _CL were determined from the average of 10 points of the analysis results of the obtained characteristic X-rays. Note that “perform composition analysis at the center” means that the electron beam having the spot diameter of 0.4 μm is irradiated around the position, and an average of 10 points of the obtained characteristic X-ray analysis results is obtained. . Further, a line L _L having a width of 50 μm is drawn in parallel with the substrate surface at the position L, the lengths of the major axis and the minor axis are obtained for each crystal grain crossing the line L _L , and the major axis length is changed to the minor axis length. in seeking the aspect ratio of crystal grains each by dividing, to obtain an average aspect ratio a _L at position H by averaging the individual aspect ratios.
The position H that enters the inside of the hard coating layer from the surface of the hard coating layer is the center of the spot, and an electron beam with a spot diameter of 0.4 μm is irradiated, that is, the position H is the center and 0 from the surface of the hard coating layer. Irradiate the electron beam from the position inside the 3 μm hard coating layer to the position inside the 0.7 μm hard coating layer, and obtain the Al content ratio X from the average of 10 points of the analysis result of the characteristic X-ray obtained. _H and average chlorine content C _H are obtained, and a line L _H having a width of 50 μm is drawn in the horizontal direction from the substrate surface at position H, and the lengths of the major axis and minor axis are obtained for each crystal grain crossing the line L _H. Then, the aspect ratio of each crystal grain was determined by dividing the length of the major axis by the length of the minor axis, and the average aspect ratio A _H at the position _H was determined by averaging the individual aspect ratios.
The average thickness of the hard coating layer was measured by a cross-section using a scanning electron microscope to obtain an average value at five locations, and the average value was taken as the average thickness of the hard coating layer.
Furthermore, regarding the crystal structure of the hard coating layer, when X-ray diffraction is performed using an X-ray diffractometer and Cu—Kα ray as a radiation source, JCPDS00-038-1420 cubic TiN and JCPDS00-046-1200 cubic crystal A diffraction peak appears between the diffraction angles of the same crystal plane shown in each of AlN (for example, 36.66 to 38.53 °, 43.59 to 44.77 °, 61.81 to 65.18 °). Investigated by confirming.
Table 5 shows the results.

Then, for each of the comparative example coated tools 1 to 8 and the reference example coated tools 9 and 10, as in the present invention coated tools 1 to 10, the average Al content ratio x, the average C content ratio y of the hard coating layer, The Al content ratios x _L and y _H , the average aspect ratios a _L and a _H , the average chlorine content, the average chlorine content c _L , and the average chlorine content c _H were measured.
Further, the crystal structure of the hard coating layer was also investigated in the same manner as in the present coated tools 1 to 10.
Table 6 shows the results.

Next, the present coated tools 1 to 10, the comparative coated tools 1 to 8 and the reference in the state where each of the various coated tools is clamped to the tip of the cutter made of tool steel having a cutter diameter of 125 mm by a fixing jig. Example With respect to the coated tools 9 and 10, the following dry high speed face milling and center cut machining test of alloy steel was performed, and the flank wear width of the cutting edge was measured.
Work material: Block material of JIS / SCM440 width 100mm, length 400mm
Rotational speed: 917 min ⁻¹ ,
Cutting speed: 360 m / min,
Cutting depth: 1mm,
Single-blade feed rate: 0.1 mm / tooth,
Cutting time: 9 minutes
Table 7 shows the results of the cutting test.

As the raw material powder, cBN powder, TiN powder, TiCN powder, TiC powder, Al powder, and Al ₂ O ₃ powder each having an average particle diameter in the range of 0.5 to 4 μm were prepared. The mixture is blended in the composition shown in FIG. 1, wet mixed with a ball mill for 80 hours, dried, and then pressed into a green compact having a diameter of 50 mm × thickness: 1.5 mm under a pressure of 120 MPa. The green compact is sintered in a vacuum atmosphere at a pressure of 1 Pa at a predetermined temperature within a range of 900 to 1300 ° C. for 60 minutes to obtain a presintered body for a cutting edge piece. In addition, Co: 8% by mass, WC: remaining composition, and diameter: 50 mm × thickness: 2 mm, superposed on a WC-based cemented carbide support piece with a normal super-high pressure Insert into the sintering machine and under normal conditions Pressure: 4 GPa, temperature: 1200 ° C. to 1400 ° C. at a predetermined temperature holding time: 0.8 hour sintering, and after sintering, the upper and lower surfaces are polished using a diamond grindstone, and wire discharge It is divided into predetermined dimensions by a processing device, and further Co: 5 mass%, TaC: 5 mass%, WC: remaining composition and ISO standard CNGA1204112 shape (thickness: 4.76 mm × inscribed circle diameter: 12. The brazing part (corner part) of the insert body made of a WC-based cemented carbide with a 7 mm 80 ° rhombus) has a composition consisting of Zr: 37.5%, Cu: 25%, Ti: the rest in volume%. After brazing using a brazing material of Ti alloy and having a predetermined dimension, the cutting edge is subjected to honing with a width of 0.13 mm and an angle of 25 °, and then subjected to final polishing to ISO standards. CNGA12 The tool substrate b - d having the insert shape of 412 was produced, respectively.

Then, these tool substrate i ~ the surface of the two, using a conventional chemical vapor deposition apparatus under the conditions shown in Table _{3, (Ti 1-X Al} X) of the present invention (C _{Y N 1-Y)} layer The present invention coated tools 11 to 15 shown in Table 9 were manufactured by vapor-depositing with a target layer thickness.

For the purpose of comparison, the same tool substrate i ~ the surface of the two, using a conventional chemical vapor deposition apparatus under the conditions shown in Table _{4, (Ti 1-x Al} x) of Comparative Example (C _{y N 1-} Comparative example-coated tools 11 to 14 shown in Table 10 were manufactured by vapor deposition forming _y ) with a target layer thickness.

For reference, (Ti _1-x Al _x ) (C _y N _1-y ) of the reference example is set to the target layer thickness by arc ion plating on the surface of the tool substrate A using a conventional physical vapor deposition apparatus. A reference example-coated tool 15 shown in Table 10 was manufactured by vapor deposition.
The arc ion plating conditions are the same as the conditions shown in the first embodiment.

Next, with respect to the hard coating layers of the present invention coated tools 11 to 15, the average Al content ratio X, the average C content ratio Y, the Al content ratios X _L and X _H , and the average aspect ratios A _L and A of the hard coating layer. _H , average chlorine content, average chlorine content C _L , average chlorine content C _H , and the crystal structure of the hard coating layer were measured using the same method as shown in Example 1.
Table 9 shows the results.

Next, for each of the comparative example coated tools 11 to 14 and the reference example coated tool 15, the average Al content ratio x, the average C content ratio y, and Al of the hard coating layer are the same as in the present invention coated tools 11 to 15. The content ratio x _L , y _H , average aspect ratio a _L , a _H , average chlorine content, average chlorine content c _L , average chlorine content c _H , and crystal structure of the hard coating layer were measured.
Table 10 shows the results.

Next, in the state where each of the above various coated tools is screwed to the tip of the tool steel tool with a fixing jig, the present coated tools 11 to 15, the comparative coated tools 11 to 14, and the reference coated samples The tool 15 was subjected to the following dry high-speed intermittent cutting test of carburized and quenched alloy steel, and the flank wear width of the cutting edge was measured.
Work material: JIS SCM415 (Hardness: HRC62) lengthwise equidistant four round grooved round bars,
Cutting speed: 210 m / min,
Cutting depth: 0.15mm,
Feed: 0.15mm / rev,
Cutting time: 4 minutes
Table 11 shows the results of the cutting test.

From the results shown in Tables 5 to 7 and Tables 9 to 11, the present invention coated tools 1 to 15 are formed by vapor deposition of a (Ti _1-X Al _X ) (C _Y N _1-Y ) layer having a cubic structure, The hard coating layer has a composition gradient structure in which the Al content ratio gradually increases from the interface between the hard coating layer and the substrate toward the surface layer side of the hard coating layer, and is different between the interface side and the surface layer side. In addition, it has a composition gradient structure in which the average chlorine content is gradually reduced, and has excellent adhesion, lubricity, and chipping resistance in high-speed milling machining or high-speed outer diameter intermittent machining of alloy steel. Demonstrate and wear resistance.
On the other hand, all of the comparative example coated tools 1-8, 11-14, and the reference example coated tools 9, 10, 15 not only cause abnormal damage such as chipping, chipping, and peeling on the hard coating layer. It is clear that the service life is reached in a relatively short time.

As described above, the coated tool of the present invention can be used not only for high-speed milling cutting of alloy steel and high-speed intermittent cutting of outer diameter, but also as a coating tool for various work materials, and for a long period of use. Since it exhibits excellent wear resistance, it can satisfactorily respond to higher performance of cutting equipment, labor saving and energy saving of cutting, and cost reduction.

Claims (4)

On the surface of the substrate composed of either tungsten carbide-based cemented carbide, titanium carbonitride-based cermet, or cubic boron nitride-based ultra-high pressure sintered body,
(A) a hard coat layer of a composite carbonitride layer of Ti and Al on cubic flat HitoshisoAtsu 2~20μm are the made form,
(B) The hard coating layer has an average composition,
_{Formula: (Ti 1-X Al X} ) (C Y N 1-Y)
In this case, the Al content ratio X and the C content ratio Y (where X and Y are atomic ratios) satisfy 0.55 ≦ X ≦ 0.95 and 0.0005 ≦ Y ≦ 0.005, respectively. Satisfied,
(C) From the interface between the hard coating layer and the substrate, composition analysis is performed centering on the position L entering the inside of the 0.5 μm hard coating layer, and the Al content of the composite carbonitride of Ti and Al having a cubic structure When the ratio is obtained and the average value is X _L (however, the atomic ratio), the Al content ratio X _L is 0.55 ≦ X _L ≦ 0.70, and is 0 from the surface layer of the hard coating layer. The composition analysis is performed centering on the position H inside the hard coating layer of 5 μm, the Al content ratio of the composite carbonitride of Ti and Al having a cubic structure is obtained, and the average value is calculated as X _H (however, the atomic ratio ), The Al content ratio X _H is 0.80 ≦ X _H ≦ 0.95, and the Al content ratio in the hard coating layer is determined from the interface side between the hard coating layer and the substrate. It has a composition gradient structure that gradually increases toward the surface side of
(D) From the interface between the hard coating layer and the substrate, the long axis width of each of the composite carbonitride crystal grains of Ti and Al having a cubic structure existing at a position L entering the inside of the 0.5 μm hard coating layer, seeking short axis width and the ratio of the long axis width and the width of the short axis of their crystal grains and an average aspect ratio a _L, the average aspect ratio a _L is 1 to 2, also the surface layer of the hard coating layer The long axis width and the short axis width are obtained for each of the Ti and Al composite carbonitride crystal grains having a cubic structure existing at the position H inside the 0.5 μm hard coating layer. and when the ratio of the width of the short axis and an average aspect ratio a _H, the surface-coated cutting tool, wherein the average aspect ratio a _H is 3-10.   The surface-coated cutting tool according to claim 1, wherein an average chlorine content contained in the hard coating layer is 0.001 to 1.0 atomic%. From the interface between the hard coating layer and the substrate, composition analysis is performed centering on the position L entering the inside of the 0.5 μm hard coating layer, the content ratio of chlorine is obtained, and the average value is calculated as the average chlorine content _CL . Then, the average chlorine content _{C L} is 0.02 to 1.0 atomic%, and, from the surface layer of the hard coating layer, a composition analysis about the position H which has entered the interior of 0.5μm hard layer The chlorine content is determined, and the average value is defined as the average chlorine content C _{H. The} average chlorine content C _H is 0.001 to 0.01 atomic%, and the average in the hard coating layer. The surface coating according to claim 2, wherein the chlorine content has a composition gradient structure that gradually decreases from the interface side between the hard coating layer and the substrate toward the surface side of the hard coating layer. Cutting tools. The hard coating layer, at least, the manufacturing method of the surface-coated cutting tool according to any one of claims 1 to 3, characterized in that the vapor deposited by chemical vapor deposition containing trimethyl aluminum as a reaction gas component.