JP4466848B2 - A surface-coated cermet cutting tool that exhibits excellent chipping resistance with a hard coating layer in high-speed intermittent cutting - Google Patents

Description

  The present invention relates to a surface-coated cermet cutting tool (hereinafter referred to as a coated cermet tool) that exhibits excellent chipping resistance with a hard coating layer, particularly in high-speed intermittent cutting of various types of steel and cast iron.

Conventionally, as a coated cermet tool, a base made of tungsten carbide (hereinafter referred to as WC) based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) based cermet (hereinafter collectively referred to as a tool base) On the surface)
(1) Ti carbide (hereinafter referred to as TiC) layer, nitride (hereinafter also referred to as TiN) layer, carbonitride (hereinafter referred to as TiCN), each of which is formed by chemical vapor deposition or physical vapor deposition. 1), a carbon oxide (hereinafter referred to as TiCO) layer, and a carbonitride oxide (hereinafter referred to as TiCNO) layer, and an overall average layer thickness of 3 to 20 μm. A Ti compound layer having
(2) An aluminum oxide (hereinafter referred to as α-type Al ₂ O ₃ ) layer having an α-type crystal structure in an upper layer formed by chemical vapor deposition and having an average layer thickness of 1 to 14 μm,
There is known a surface-coated cermet cutting tool formed by vapor-depositing the hard coating layer composed of (a) and (b) above, and this coated cermet tool is a work material such as various steels and cast iron. It is used for continuous cutting and intermittent cutting.
Japanese Unexamined Patent Publication No. 6-31503

In recent years, the performance of cutting machines has been remarkable. On the other hand, there is a strong demand for labor saving, energy saving, and cost reduction for cutting, and along with this, cutting has been on the trend of higher speed. For coated cermet tools, there is no problem when this is used for cutting under normal conditions such as steel and cast iron, but this is especially fast for high-speed intermittent cutting with severe cutting conditions, that is, extremely fast cutting edges. When used for high-speed interrupted cutting with mechanical thermal shock at a pitch, the Ti compound layer constituting the hard coating layer has a relatively high high-temperature strength, and the α-type Al ₂ O ₃ layer is relatively In addition, the α-type Al ₂ O ₃ layer is particularly deficient in high-temperature strength and heat resistance, and the Ti compound layer is not sufficiently satisfactory in high-temperature strength. Coating layer Mappings easily (small chipping) occurs, the reach this result relatively short time service life at present.

In view of the above, the inventors of the present invention constitute a hard coating layer of the above-described conventional coated cermet tool, in particular, a TiCN layer (hereinafter referred to as a conventional TiCN layer) of the Ti compound layer and α-type Al. Focusing on the ₂ O ₃ layer (hereinafter referred to as the conventional Al ₂ O ₃ layer), research was conducted to further improve the high-temperature strength of both layers and to develop a coated cermet tool that does not generate chipping under high-speed intermittent cutting conditions. As a result,
(Aa) The conventional TiCN layer is a normal chemical vapor deposition apparatus.
Reaction gas composition - by _{volume%, TiCl 4: 2~10%,} CH 3 CN: 0.5~3%, N 2: 10~30%, H 2: remainder,
Reaction atmosphere temperature: 850-950 ° C.
Reaction atmosphere pressure: 3 to 13 kPa,
However, prior to the formation of the conventional TiCN layer,
Reaction gas composition - by _{volume%, TiCl 4: 0.52~0.84%,} C 3 H 6 ( _{methylethylene): 2 ~5%, N 2} : 20~40%, H 2: remainder,
Reaction atmosphere temperature: 700 to 750 ° C.
Reaction atmosphere pressure: 3 to 7 kPa,
Deposition time: 1-3 hours
In this condition, a TiCN thin film as a seed thin film (hereinafter referred to as a TiCN seed thin film) is preferably formed with an average layer thickness of 0.02 to 0.5 μm, and the above-described conventional TiCN layer is formed on the TiCN seed thin film. When the TiCN layer is formed under the same conditions, the TiCN layer at the time of formation is significantly affected by the crystal arrangement of the TiCN seed thin film, and the TiCN layer is formed as a result. (Hereinafter referred to as a history TiCN layer) has a higher temperature strength than that of the conventional TiCN layer, and has excellent mechanical and thermal shock resistance.

(Ab) About the conventional TiCN layer and the history TiCN layer constituting the lower layer of the hard coating layer of the coated cermet tool,
Using a field emission scanning electron microscope, as shown in the schematic explanatory diagrams of FIGS. 1A and 1B, electron beams are individually applied to crystal grains having a cubic crystal lattice existing within the measurement range of the surface polished surface. Irradiate and use an electron backscatter diffraction image apparatus, and the normal of the {112} plane, which is the crystal plane of the crystal grain, with respect to the normal of the polished surface with respect to the normal of the surface-polished surface at an interval of 0.1 μm / step Measure the inclination angle to be made, divide the measurement inclination angle within the range of 0-45 degrees out of the measurement inclination angle for each pitch of 0.25 degree, and totalize the frequency existing in each division When the tilt angle number distribution graph is created, the conventional TiCN layer has an unbiased tilt angle number within the range of the measured tilt angle distribution of the {112} plane within the range of 0 to 45 degrees as illustrated in FIG. While the distribution graph is shown, the history TiCN layer is shown in FIG. As can be seen, a sharp maximum peak appears at a specific position in the tilt angle section, and the sharp maximum peak has a height that appears in the tilt angle section on the horizontal axis of the graph. It changes depending on the pressure, and the inclination angle division position on the horizontal axis of the graph also changes depending on the TiCl ₄ content of the reaction gas.

( Ac ) As described above, when forming the TiCN seed thin film, by setting the content of TiCl _{4 in} the reaction gas to 0.52 to 0.84 %, the inclination angle number distribution graph of the hysteresis TiCN layer A sharp maximum peak appears in the range of 2.00 to 6.50 degrees of the tilt angle section, and the reaction atmosphere temperature is set to 700 to 750 ° C. and the reaction atmosphere pressure is set to 3 to 7 kPa. An inclination angle distribution graph in which the total of the frequencies existing within a range of 10 degrees occupies a ratio of 61 to 75 % of the entire frequency in the inclination angle distribution distribution graph is shown. In this case, according to the test result, , even less than 0.52% content of as TiCl ₄ shown in Table 3, also beyond the content is 0.84% at any tilt angle frequency distribution graph of the history TiCN layer in each case, Tilt angle division position of the high peak is to appear at a position outside the range of 2.00 to 6.50 degrees, it becomes impossible to secure a high temperature strength which is superior in one step on the result the history TiCN layer, In regard to the reaction atmosphere temperature and the reaction atmosphere pressure, whether the temperature is less than 700 ° C., more than 750 ° C., even if the pressure is less than 3 kPa, or more than 7 kPa, The frequency ratio existing in the range of 0 to 10 degrees may be less than 61 %, and in this case, the high temperature strength cannot be further improved.

(Ba) The conventional Al ₂ O ₃ layer is a normal chemical vapor deposition apparatus.
Reaction gas composition - by _{volume%, AlCl 3: 1~5%,} CO 2: 0.5~10%, HCl: 0.3~3%, H 2 S: 0.02~0.4%, H 2 :remaining,
Reaction atmosphere temperature: 950-1100 ° C.
Reaction atmosphere pressure: 3 to 13 kPa,
However, prior to the conventional Al ₂ O ₃ layer formation,
Reaction gas composition - by _{volume%, AlCl 3: 1~5%,} CO 2: 5~10%, HCl: 0.3~3%, CH 3 CN: 0.02~0.1%, NO: 0. 02~ 0.2%, _{H 2:} remainder,
Temperature of reaction atmosphere: 840 ~900 ℃,
Reaction atmosphere pressure: 5 to 13 kPa,
Deposition time: 1 to 1.5 hours
In conditions, preferably as the Al ₂ O ₃ thin film (hereinafter, Al referred ₂ O ₃ or thin) species thin with an average layer thickness of 0.02~0.5μm is formed and the Al ₂ O ₃ or thin When forming the above-described prior the Al ₂ O ₃ layer α type the Al ₂ O ₃ layer under the same conditions as the conditions for forming the above forming the α-type the Al ₂ O ₃ layer at the time of the crystals of the Al ₂ O ₃ or thin The α-type Al ₂ O ₃ layer (hereinafter referred to as a history Al ₂ O ₃ layer) formed as a result of the significant influence of the arrangement and the sufficient history of the α-type Al ₂ O ₃ layer The high-temperature strength and heat resistance possessed by itself are not impaired, and the high-temperature strength is further improved as compared with the conventional Al ₂ O ₃ layer.

(Bb) The history Al ₂ O ₃ layer and the conventional Al ₂ O ₃ layer in (a) above are shown schematically in FIGS. 2A and 2B using a field emission scanning electron microscope. As described above, each of the Al ₂ O ₃ crystal grains having a hexagonal crystal lattice existing within the measurement range of the polished surface is irradiated with an electron beam, and a predetermined region is set to 0.1 μm / step using an electron backscatter diffraction image apparatus. Is measured with respect to the normal of the surface polished surface at an interval of the inclination angle formed by the normal of the {0001} plane which is the crystal plane of the crystal grain, and within the range of 0 to 45 degrees of the measured inclination When the inclination angle number distribution graph is created by dividing the measured inclination angles at 0.25 degree pitches and adding up the frequencies existing in each section, the conventional Al ₂ O ₃ layer is As illustrated in FIG. 6, the distribution of measured inclination angles on the {0001} plane is within the range of 0 to 45 degrees. Whereas it illustrates an unbiased inclination angle frequency distribution graph, the history the Al ₂ O ₃ layer, as illustrated in FIG. 4, appear sharp highest peak in a specific position of the tilt angle indicator, the sharp maximum The height of the peak that appears in the tilt angle section of the horizontal axis of the graph varies depending on the reaction atmosphere temperature and the reaction atmosphere pressure during the formation of the Al ₂ O ₃ seed thin film, and the tilt angle section position of the horizontal axis of the graph is the same as the CH of the reaction gas. ₃ Change according to CN content.

(Bc) As described above, when the Al ₂ O ₃ seed thin film is formed, the history Al ₂ O ₃ layer is formed by setting the content of CH ₃ CN in the reaction gas to 0.02 to 0.1%. In the inclination angle number distribution graph, the sharp maximum peak appears in the range of 0 to 10 degrees of the inclination angle section, the reaction atmosphere temperature is 840 to 900 ° C., and the reaction atmosphere pressure is 5 to 13 kPa, The total number of frequencies within the range of 0 to 10 degrees shows a graph corresponding to 45 to 71 % of the total frequency in the tilt angle frequency distribution graph. In this case, the test results According to the graph, even when the content of CH ₃ CN is less than 0.02% and the content exceeds 0.1%, the highest peak in the inclination angle number distribution graph of the above-mentioned history Al ₂ O ₃ layer Tilt angle section position exceeds 10 degrees As a result, it becomes impossible to ensure the desired excellent high-temperature strength in the hysteresis Al ₂ O ₃ layer, and the reaction atmosphere temperature and the reaction atmosphere pressure are less than 840 ° C. In addition, even if the temperature exceeds 900 ° C., the pressure is less than 5 kPa, and the pressure exceeds 13 kPa, both are within the range of 0 to 10 degrees in the inclination angle number distribution graph of the hysteresis Al ₂ O ₃ layer. The frequency ratio present is less than 45%, and the desired improvement effect cannot be obtained in the high temperature strength.

(Bd) As described above, a coating in which the upper layer of the hard coating layer is composed of the hysteresis Al ₂ O ₃ layer and one of the lower layers is composed of a Ti compound layer composed of the hysteresis TiCN layer. The cermet tool has excellent chipping resistance because the hard coating layer has extremely high temperature strength, especially in high-speed intermittent cutting where mechanical thermal shock is applied to the cutting edge at an extremely fast pitch. As a result, the research results shown in (A) and (B) have been obtained.

The present invention has been made based on the above research results, and on the surface of a tool base composed of a WC-based cemented carbide or TiCN-based cermet,
(1) The lower layer consists of one or more of TiC layer, TiN layer, TiCN layer, TiCO layer, and TiCNO layer, all formed by chemical vapor deposition, and an overall average layer of 3 to 20 μm A Ti compound layer having a thickness;
(2) an α-type Al ₂ O ₃ layer having an α-type crystal structure in a state where the upper layer is formed by chemical vapor deposition;
In the coated cermet cutting tool formed by vapor-depositing the hard coating layer composed of (1) and (2) above,
(A) One of the Ti compound layers of (1) above is
Reaction gas composition - by _{volume%, TiCl 4: 0.52~0.84%,} C 3 H 6 ( _{methylethylene): 2~5%, N 2:} 20~40%, H 2: remainder,
Reaction atmosphere temperature: 700 to 750 ° C.
Reaction atmosphere pressure: 3 to 7 kPa,
Deposition time: 1-3 hours
Under the conditions, through a TiCN seed thin film formed by chemical vapor deposition to an average layer thickness of 0.02 to 0.5 μm,
Reaction gas composition - by _{volume%, TiCl 4: 2~10%,} CH 3 CN: 0.5~3%, N 2: 10~30%, H 2: remainder,
Reaction atmosphere temperature: 850-950 ° C.
Reaction atmosphere pressure: 3 to 13 kPa,
Under the conditions (corresponding to the conventional vapor deposition conditions)
As it is formed,
Using electric field emission scanning electron microscope, the crystal grains each having a cubic crystal lattice existing in a measurement range of the surface polishing surface is irradiated with an electron beam, using an electron backscattering diffraction image device, 0 a predetermined area The inclination angle formed by the normal of the {112} plane, which is the crystal plane of the crystal grain, is measured with respect to the normal of the surface-polished surface at an interval of 1 μm / step. In the inclination angle number distribution graph obtained by dividing the measured inclination angles within the range of degrees into pitches of 0.25 degrees and totaling the frequencies existing in the respective sections, 2.00 to 6.50 degrees Inclination angle distribution in which the highest peak exists in the inclination angle section within the range, and the sum of the frequencies existing in the range of 0 to 10 degrees occupies 61 to 75 % of the entire frequency in the inclination angle distribution graph History TiCN layer showing graph,
(B) The α-type Al ₂ O ₃ layer is
Reaction gas composition - by _{volume%, AlCl 3: 1~5%,} CO 2: 5~10%, HCl: 0.3~3%, CH 3 CN: 0.02~0.1%, NO: 0. 02~0.2%, _{H 2:} remainder,
Reaction atmosphere temperature: 840 to 900 ° C.
Reaction atmosphere pressure: 5 to 13 kPa,
Deposition time: 1 to 1.5 hours
Under the conditions, through the Al ₂ O ₃ seed thin film formed by chemical vapor deposition to an average layer thickness of 0.02 to 0.5 μm ,
Reaction gas composition - by _{volume%, AlCl 3: 1~5%,} CO 2: 0.5~10%, HCl: 0.3~3%, H 2 S: 0.02~0.4%, H 2 :remaining,
Reaction atmosphere temperature: 950-1100 ° C.
Reaction atmosphere pressure: 3 to 13 kPa,
In the above conditions (conditions corresponding to conventional vapor deposition conditions), chemical vapor deposition is formed to an average layer thickness of 1 to 14 μm ,
Using a field emission scanning electron microscope, each crystal grain having a hexagonal crystal lattice existing within the measurement range of the surface polished surface is irradiated with an electron beam, and a predetermined region is set to 0. 0 using an electron backscatter diffraction image apparatus. At an interval of 1 μm / step, an inclination angle formed by a normal line of the {0001} plane, which is a crystal plane of the crystal grain, is measured with respect to a normal line of the polished surface. In the inclination angle distribution graph formed by dividing the measured inclination angles within the range of 0.25 degrees into pitches and adding up the frequencies existing in each section, the inclination angles within the range of 0 to 10 degrees Chemistry showing an inclination angle distribution graph in which the highest peak exists in the section and the total of the frequencies existing in the range of 0 to 10 degrees occupies 45 to 71 % of the entire frequency in the inclination angle distribution graph Α-type in the state of vapor deposition History the Al ₂ O ₃ layer having a crystal structure,
It is characterized by a coated cermet tool that exhibits excellent chipping resistance with a hard coating layer in high-speed intermittent cutting.

Next, the reason why the constituent layers of the hard coating layer of the coated cermet tool of the present invention are numerically limited as described above will be described below.
(A) (a) Ti compound layer (lower layer)
The Ti compound layer itself has high-temperature strength, and the presence of the Ti compound layer allows the hard coating layer to have high-temperature strength, and is strong against both the tool base and the hysteresis Al ₂ O ₃ layer that is the upper layer. It has an action that contributes to improving the adhesion of the hard coating layer to the tool substrate, but if the total average layer thickness is less than 3 μm, the above-mentioned action cannot be sufficiently exerted, whereas the total average layer thickness When the thickness exceeds 20 μm, it becomes easy to cause thermoplastic deformation particularly by high-speed intermittent cutting accompanied by generation of high heat, which causes uneven wear. Therefore, the total average layer thickness is determined to be 3 to 20 μm.

(B) History TiCN layer (lower layer)
As described above, when the TiCN seed thin film is formed, by setting the content of TiCl _{4 in} the reaction gas to 0.52 to 0.84 %, the sharpest peak in the tilt angle distribution graph is the tilt angle section. When the reaction atmosphere temperature is 700 to 750 ° C. and the reaction atmosphere pressure is 3 to 7 kPa, the frequency that is in the range of 0 to 10 degrees appears. The hysteresis TiCN layer showing the inclination angle frequency distribution graph in which the total accounted for 61 to 75 % of the total frequency in the inclination angle frequency distribution graph is formed, and as a result, the history TiCN layer was further improved. However, if the average layer thickness is less than 2.5 μm, it is not possible to provide the hard coating layer with the desired excellent high-temperature strength. If the layer thickness exceeds 15 [mu] m, easily heat the plastic deformation which causes partial wear is generated, since it becomes worn accelerates, determined the average layer thickness and 2.5～15Myuemu.

(B) History Al ₂ O ₃ layer (upper layer)
The history Al ₂ O ₃ layer is an inclination angle distribution graph, where the sharpest peak appears in the range of 0 to 10 degrees of the inclination angle section, and the sum of the frequencies existing in the range of 0 to 10 degrees is , Showing an inclination angle distribution graph occupying a ratio of 45 to 71 % of the entire frequency in the inclination angle distribution graph, and as a result, it has excellent high-temperature strength and improves chipping resistance. _The excellent high-temperature hardness and heat resistance of the ₂ O ₃ layer itself contributes to improving the wear resistance of the hard coating layer. However, if the average layer thickness is less than 1 μm, the hard coating layer can exhibit sufficient wear resistance. On the other hand, if the average layer thickness exceeds 14 μm and becomes too thick, chipping tends to occur. Therefore, the average layer thickness was set to 1 to 14 μm.

  In addition, for the purpose of identification before and after the use of the cutting tool, a TiN layer having a golden color tone may be vapor-deposited as necessary, but the average layer thickness in this case may be 0.1 to 1 μm, This is because if the thickness is less than 0.1 μm, a sufficient discrimination effect cannot be obtained, while the discrimination effect by the TiN layer is sufficient with an average layer thickness of up to 1 μm.

The coated cermet tool of the present invention comprises a TiCN layer which is one of the Ti compound layers constituting the lower layer of the hard coating layer of the conventional coated cermet tool and an α-type Al ₂ O ₃ layer which is the upper layer. As described above, high-speed intermittent cutting of steel and cast iron, etc., in which mechanical thermal shock is applied to the cutting edge at a very fast pitch by configuring it with a history TiCN layer and a history Al ₂ O ₃ layer that are further improved in high-temperature strength. Even in the cutting process, excellent wear resistance is exhibited without occurrence of chipping.

  Next, the coated cermet 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, TiN powder, and Co powder each having an average particle diameter of 1 to 3 μm are prepared. These raw material powders are shown in Table 1. After blending into the blending composition, adding wax, ball mill mixing in acetone for 24 hours, drying under reduced pressure, press-molding into a compact of a predetermined shape at a pressure of 98 MPa, and this compact in a vacuum of 5 Pa. Slow stipulated in ISO · CNMG120412 by vacuum sintering at a predetermined temperature within the range of 1370 to 1470 ° C under the condition of holding for 1 hour, and after sintering, the honing process of R: 0.07mm is applied to the cutting edge part. Tool bases A and B made of a WC-base cemented carbide having an outer tip shape were manufactured.

Further, as raw material powders, TiCN (mass ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, TaC powder, WC powder, Co powder, all having an average particle diameter of 0.5 to 2 μm. , And Ni powder, these raw material powders are blended in the blending composition shown in Table 1 , wet mixed for 24 hours with a ball mill, dried, and then pressed into a compact at a pressure of 98 MPa. The powder is sintered in a nitrogen atmosphere of 1.3 kPa at a temperature of 1540 ° C. for 1 hour, and after sintering, the cutting edge portion is subjected to a honing process of R: 0.07 mm to achieve ISO standard / CNMG120212. The tool bases b and e made of TiCN base cermet having the following chip shape were formed.

Next, a Ti compound layer is formed on the surface of these tool bases as a lower layer of the hard coating layer under the conditions shown in Table 2 using a normal chemical vapor deposition apparatus. When forming the history TiCN layer, the TiCN seed thin film is first subjected to the conditions shown in Table 3 , that is, the conditions of the seed thin films c, d, f, and g for the target history TiCN layer determined based on the test results. Subsequently, a history TiCN layer was formed by vapor deposition with the combination and target layer thickness shown in Table 5 under the same conditions as the conventional TiCN layer formation conditions shown in Table 2 as described above. In the combinations shown in Table 5 , the Al ₂ O ₃ seed thin film is subjected to the conditions shown in FIG. 4 , that is, the seed thin films A, B, E, and K conditions for the target history Al ₂ O ₃ layer determined based on the test results. form Then, as described above, a history Al ₂ O ₃ layer is vapor-deposited with the combination and target layer thickness shown in Table 5 under the same conditions as the conventional Al ₂ O ₃ layer formation conditions shown in Table _3. By this, this invention coated cermet tool 1-5 was manufactured, respectively.

For comparison purposes, as shown in Table 5 , the Ti compound layer including the conventional TiCN layer and the α-type Al ₂ O ₃ layer (conventional Al ₂ O ₃ layer), which are the lower layers of the hard coating layer, are also shown. Conventionally coated cermet tools 1 to 5 were produced by forming a hard coating layer under the same conditions except that vapor deposition was performed under the conditions shown in Table 2 and with the target layer thickness shown in Table 5 .

Next, with respect to the hysteresis TiCN layer and the conventional TiCN layer constituting the hard coating layer of the above-described coated cermet tool of the present invention and the conventional coated cermet tool, and further to the hysteresis Al ₂ O ₃ layer and the conventional Al ₂ O ₃ layer, field emission scanning electrons An inclination angle number distribution graph was prepared using a microscope and an electron backscatter diffraction image apparatus .
That is, the inclination angle number distribution graph shows the field emission scanning electron microscope in a state where the surfaces of the hysteresis TiCN layer and the conventional TiCN layer, and further the surfaces of the hysteresis Al ₂ O ₃ layer and the conventional Al ₂ O ₃ layer are polished surfaces. A cubic crystal lattice (TiCN) existing in the measurement range of the surface polished surface with an electron beam with an acceleration voltage of 15 kV at an incident angle of 70 degrees and an irradiation current of 1 nA on the polished surface. Alternatively, each crystal grain having a hexagonal crystal lattice (Al ₂ O ₃ ) is irradiated, and an electron backscatter diffraction image apparatus is used to divide a region of 30 × 50 μm at an interval of 0.1 μm / step. The inclination angle formed by the normal of the {112} plane (TiCN layer) or {0001} plane (Al ₂ O ₃ layer), which is the crystal plane of the crystal grain, with respect to the normal is measured. Of the measured tilt angles Measuring the inclination angle is in the range of 0 to 45 degrees while divided for each pitch of 0.25 degrees, it was created by aggregating the frequencies present in each segment.

As a result, the {112} plane or {0001} plane is the highest in the inclination angle number distribution graphs of various hysteresis TiCN layers and conventional TiCN layers, and various hysteresis Al ₂ O ₃ layers and conventional Al ₂ O ₃ layers. Table 6 shows the ratio of the number of inclination angles existing in the inclination angle section showing the peak and the inclination angle number existing in the inclination angle section in the range of 0 to 10 degrees to the entire inclination angle distribution graph.

In the above-mentioned various inclination angle number distribution graphs, as shown in Table 6 , each of the hysteresis TiCN layer and the hysteresis Al ₂ O ₃ layer of the coated cermet tool of the present invention has a distribution of measured inclination angles of 2 in the {112} plane. The highest peak appears in each of the inclination angle sections in the range of 0 to 6.50 degrees and the measured inclination angle of the {0001} plane in the range of 0 to 10 degrees, and the 2.00 to 6.50 degrees and 0 to 0 degrees. While showing the inclination angle number distribution graph in which the ratio of the inclination angle numbers existing in the inclination angle section within the range of 10 degrees is 61 to 75% and 45 to 71% , respectively , the conventional TiCN of the conventional coated cermet tool Both the conventional layer and the conventional Al ₂ O ₃ layer are unbiased in the distribution of the measured inclination angles of the {112} plane and the {0001} plane within the range of 0 to 45 degrees, and the highest peak does not exist. Tilt angle division within the range of degrees The inclination angle number distribution graph in which the ratio of the number of inclination angles existing therein is also 30% or less is shown.
3 and 4 are graphs of inclination angle number distribution of the hysteresis TiCN layer and the hysteresis Al ₂ O ₃ layer of the coated cermet tool 3 of the present invention, and FIGS. 5 and 6 are the conventional TiCN layer and the conventional AlN of the conventional coated cermet tool 3. ₂ shows an inclination angle number distribution graph of the ₂ O ₃ layer.

Further, with respect to the above-described coated cermet tools 1 to 5 and the conventional coated cermet tools 1 to 5 , the Ti compound layer and the Al ₂ O ₃ layer of the hard coating layer are formed by an electron beam microanalyzer (EPMA) and an Auger spectrometer. (The longitudinal section of the layer was observed), it was confirmed that both the former and the latter had substantially the same composition as the target composition, and the thickness of the constituent layers of the hard coating layer of these coated cermet tools When measured using a scanning electron microscope (same longitudinal section measurement), all showed an average layer thickness (average value of five-point measurement) substantially the same as the target layer thickness.

Next, in the state where each of the above various coated cermet tools is screwed to the tip of the tool steel tool with a fixing jig, the present coated cermet tools 1 to 5 and the conventional coated cermet tools 1 to 5 are as follows:
Work material: JIS · SCM440 lengthwise equidistant 4 vertical grooved round bar,
Cutting speed: 450 m / min,
Incision: 1.5mm,
Feed: 0.3mm / rev,
Cutting time: 10 minutes,
Dry high-speed intermittent cutting test (normal cutting speed is 250 m / min) of alloy steel under the above conditions (cutting condition A),
Work material: JIS · S40C lengthwise equal length 4 round bar with round groove,
Cutting speed: 450 m / min,
Incision: 1.5mm,
Feed: 0.3mm / rev,
Cutting time: 10 minutes,
Dry high-speed intermittent cutting test of carbon steel under the conditions (cutting condition B) (normal cutting speed is 200 m / min),
Work material: JIS / FCD350 lengthwise equidistant round bars with 4 vertical grooves,
Cutting speed: 450 m / min,
Cutting depth: 1.6mm,
Feed: 0.32mm / rev,
Cutting time: 10 minutes,
A dry high-speed intermittent cutting test (normal cutting speed is 250 m / min) of ductile cast iron under the above conditions (cutting condition C), and the flank wear width of the cutting edge was measured in any cutting test. The measurement results are shown in Table 7 .

From the results shown in Tables 5-7 , in the coated cermet tools 1-5 of the present invention, one of the Ti compound layers and the upper layer of the lower layer of the hard coating layer are each one of the lower layers. In the layer, the {112} plane has an inclination angle of 2.00 to 6.50 degrees , and in the upper layer, the {0001} plane has an inclination angle in the range of 0 to 10 degrees. Hysteresis TiCN layer and hysteresis Al ₂ showing the gradient peak distribution graph showing the highest peak and occupying 61 to 75% and 45 to 71% of the total ratio of the frequencies existing in the gradient angle range of 0 to 10 degrees, respectively. Both the hysteresis TiCN layer and the hysteresis Al ₂ O ₃ layer have excellent high-temperature strength even in high-speed intermittent machining, which consists of an O ₃ layer, and mechanical thermal shock is applied to the cutting edge at an extremely fast pitch. From the cutting edge While the occurrence of chipping is remarkably suppressed and excellent wear resistance is exhibited, one of the Ti compound layers and the upper layer of the lower layer of the hard coating layer are respectively present in one of the lower layers. In the {112} plane, and in the above upper layer, the distribution of measured inclination angles on the {0001} plane is all unbiased within the range of 0 to 45 degrees, and the inclination angle number distribution graph without the highest peak. In the conventional coated cermet tools 1 to 5 composed of the conventional TiCN layer and the conventional Al ₂ O ₃ layer, the cutting edge portion is high because the high temperature strength of the hard coating layer is insufficient in high-speed intermittent cutting. It is clear that chipping occurs and the service life is reached in a relatively short time.

  As described above, the coated cermet tool of the present invention can be used for hard coating not only for cutting under normal conditions such as various types of steel and cast iron, but also for high-speed intermittent cutting that requires high-temperature strength for the hard coating layer. Since the layer exhibits excellent chipping resistance and excellent wear resistance over a long period of time, it is fully satisfied with high performance of cutting equipment, labor saving and energy saving of cutting processing, and cost reduction It can cope with.

It is a schematic explanatory drawing which shows the measurement range of the inclination angle of the {112} plane of the crystal grain in the TiCN layer which comprises the lower layer of a hard coating layer. Is a schematic diagram illustrating a measurement range of the inclination angle of the {0001} plane of the crystal grains in the hard coating layer α type the Al ₂ O ₃ layer constituting the. It is an inclination angle number distribution graph of the {112} plane of the history TiCN layer which constitutes the lower layer of the hard coating layer of the present coated cermet tool 3 . The inclination angle frequency distribution graph of the {0001} plane of the history the Al ₂ O ₃ layer constituting the upper layer of the hard coating layer of the present invention coated cermet tool 3. It is the inclination angle number distribution graph of the {112} plane of the conventional TiCN layer which constitutes the lower layer of the hard coating layer of the conventional coated cermet tool 3 . 6 is a graph showing the distribution of the number of inclination angles of the {0001} plane of the conventional Al ₂ O ₃ layer constituting the upper layer of the hard coating layer of the conventional coated cermet tool 3 .

Claims (1)

On the surface of the tool base composed of tungsten carbide based cemented carbide or titanium carbonitride based cermet,
(1) The lower layer is formed of one or more of Ti carbide layer, nitride layer, carbonitride layer, carbonate layer, and carbonitride oxide layer, all formed by chemical vapor deposition. And a Ti compound layer having a total average layer thickness of 3 to 20 μm,
(2) an aluminum oxide layer having an α-type crystal structure in a state where the upper layer is formed by chemical vapor deposition;
In the surface-coated cermet cutting tool formed by vapor-depositing the hard coating layer composed of (1) and (2) above,
(A) One of the Ti compound layers of (1) above is
Reaction gas composition - by _{volume%, TiCl 4: 0.52~0.84%,} C 3 H 6 ( _{methylethylene): 2~5%, N 2:} 20~40%, H 2: remainder,
Reaction atmosphere temperature: 700 to 750 ° C.
Reaction atmosphere pressure: 3 to 7 kPa,
Deposition time: 1-3 hours
Under the conditions, through a titanium carbonitride thin film as a seed thin film formed by chemical vapor deposition to an average layer thickness of 0.02 to 0.5 μm,
Reaction gas composition - by _{volume%, TiCl 4: 2~10%,} CH 3 CN: 0.5~3%, N 2: 10~30%, H 2: remainder,
Reaction atmosphere temperature: 850-950 ° C.
Reaction atmosphere pressure: 3 to 13 kPa,
Under the conditions (corresponding to the conventional vapor deposition conditions)
As it is formed,
Using a field emission scanning electron microscope, each crystal grain having a cubic crystal lattice existing within the measurement range of the surface polished surface is irradiated with an electron beam, and a predetermined region is set to 0. 0 using an electron backscatter diffraction image apparatus. The inclination angle formed by the normal of the {112} plane, which is the crystal plane of the crystal grain, is measured with respect to the normal of the surface polished surface at an interval of 1 μm / step. In the inclination angle number distribution graph in which the measured inclination angles within the range of 0.25 degrees are divided for each pitch of 0.25 degrees and the frequencies existing in each division are tabulated, the range of 2.00 to 6.50 degrees An inclination angle distribution graph in which the highest peak exists in the inclination angle section and the sum of the frequencies existing in the range of 0 to 10 degrees occupies a ratio of 61 to 75 % of the entire frequency in the inclination angle distribution graph. Showing a titanium carbonitride layer,
(B) The aluminum oxide layer of (2) above,
Reaction gas composition - by _{volume%, AlCl 3: 1~5%,} CO 2: 5~10%, HCl: 0.3~3%, CH 3 CN: 0.02~0.1%, NO: 0. 02~0.2%, _{H 2:} remainder,
Reaction atmosphere temperature: 840 to 900 ° C.
Reaction atmosphere pressure: 5 to 13 kPa,
Deposition time: 1 to 1.5 hours
Under the above conditions, through an aluminum oxide thin film as a seed thin film formed by chemical vapor deposition with an average layer thickness of 0.02 to 0.5 μm,
Reaction gas composition - by _{volume%, AlCl 3: 1~5%,} CO 2: 0.5~10%, HCl: 0.3~3%, H 2 S: 0.02~0.4%, H 2 :remaining,
Reaction atmosphere temperature: 950-1100 ° C.
Reaction atmosphere pressure: 3 to 13 kPa,
In the above conditions (conditions corresponding to conventional vapor deposition conditions), chemical vapor deposition is formed to an average layer thickness of 1 to 14 μm ,
Using a field emission scanning electron microscope, each crystal grain having a hexagonal crystal lattice existing in the measurement range of the surface polished surface is irradiated with an electron beam, and the measurement range is set to 0 using an electron backscatter diffraction image apparatus. The inclination angle formed by the normal line of the {0001} plane, which is the crystal plane of the crystal grain, is measured with respect to the normal line of the polished surface at an interval of 1 μm / step. In the inclination angle distribution graph formed by dividing the measured inclination angles within the range of ˜45 degrees into the pitches of 0.25 degrees and totaling the frequencies existing in the respective sections, within the range of 0 to 10 degrees. Inclination angle number distribution graph in which the highest peak exists in the inclination angle section and the sum of the frequencies existing in the range of 0 to 10 degrees occupies a ratio of 45 to 71 % of the whole frequency in the inclination angle distribution graph α while chemical vapor deposited showing the Aluminum oxide layer having a crystal structure,
A surface-coated cermet cutting tool that exhibits excellent chipping resistance with a high hard coating layer in high-speed intermittent cutting.

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