JP5975214B2 - Surface coated cutting tool - Google Patents

Description

  The present invention relates to a surface-coated cutting tool (hereinafter referred to as a coated tool). More specifically, for example, a difficult-to-cut material that is severely welded to the cutting edge when machining titanium alloy, heat-resistant alloy steel, stainless steel, etc. In addition, the present invention relates to a coated tool that exhibits excellent chipping resistance and wear resistance when the hard coating layer is machined under high-speed cutting conditions with remarkable impact and weldability to the cutting edge.

  In general, coated tools are used for turning and planing of work materials such as various types of steel and cast iron, inserts that can be used detachably attached to the tip of a cutting tool, drilling processing of work materials, etc. There are drills, miniature drills, solid type end mills used for chamfering, grooving, shoulder processing, etc. of the work material, etc. Also, inserts are detachably attached and cutting is performed in the same way as solid type end mills Insert type end mill tools are known.

  In addition, as a conventional coated tool, for example, an insert body having a structure in which an ultrahigh pressure sintering reaction product is interposed at an interface between a cubic boron nitride phase forming a dispersed phase and a titanium nitride phase forming a continuous phase. A surface-coated cubic boron nitride-based ultra-high pressure sintered material cutting tool having a hard coating layer deposited on the surface, wherein (a) the hard coating layer has a lower layer having an average layer thickness of 1 to 3 μm and 0 An upper layer having an average layer thickness of 3 to 3 μm, (b) the lower layer is composed of a composite nitride layer of Cr and Al satisfying a specific composition formula, and (c) the upper layer is a single layer average A composite nitride layer of Cr and Al, which has a laminated structure of thin layers A and B each having a thickness of 0.05 to 0.3 μm, and the thin layer A satisfies a specific composition formula, a thin layer B has a structure of Cr nitride (CrN) layer, which makes it difficult to cut hard difficult-to-cut materials. Surface-coated cubic boron nitride containing group ultrahigh pressure sintered material cutting tool made to exert over the surface finish was excellent in continued cutting a long has been known (e.g., see Patent Document 1).

  Furthermore, another conventional coated tool is known which has improved wear resistance and fracture resistance by vapor-depositing a hard coating layer comprising an (Al, Ti, M) N layer on the surface of the tool base. However, such a hard coating layer is prepared by, for example, inserting a tool base into an arc ion plating apparatus (AIP apparatus) which is one type of physical vapor deposition apparatus shown schematically in FIG. For example, between a cathode electrode in which an alloy corresponding to the composition of the hard coating layer is set, for example, an Al—Ti—M alloy, and the anode electrode while being heated to a temperature of 500 ° C., for example, current: 90 A Arc discharge is generated under the conditions of the above, and simultaneously, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 2 Pa. On the other hand, a tool base is applied with a bias voltage of, for example, −100 V Base (Al, Ti, M) it is also known to be produced by depositing a hard coating layer consisting of N layers on the surface (e.g., see Patent Document 2).

JP 2008-18507 A Japanese Patent No. 2793773

  However, the automation of cutting machines in recent years has been remarkable. On the other hand, there is a strong demand for labor saving, energy saving, and cost reduction for cutting, and as a result, cutting tools have as much influence as possible on the type of work material. There is a tendency to demand cutting tools that can cut as many grades as possible, but in conventional coated tools, this is at the normal cutting speed of work materials such as steel and cast iron. No problem when used for cutting, but high-speed cutting conditions with difficult to cut materials such as titanium alloy, heat-resistant alloy steel, and stainless steel with high heat generation and remarkable impact and weldability to the cutting edge When cutting with, the work material and chips are heated to a high temperature due to the heat generated during cutting, and the viscosity increases, and as a result, the weldability to the surface of the hard coating layer further increases. Fruit, increased chipping (fine chipping) rapidly at the cutting edge. This is the current situation is reached in a relatively short time service life due.

  Therefore, the technical problem to be solved by the present invention, that is, the object of the present invention is that even when difficult-to-cut materials such as titanium alloy, heat-resistant alloy steel, and stainless steel are cut under high-speed cutting conditions with high heat generation. It is to provide a coated tool that exhibits excellent impact resistance, welding resistance, chipping resistance and wear resistance.

  In view of the above, the inventors of the present invention have an excellent hard coating layer particularly when cutting difficult-to-cut materials such as titanium alloy, heat-resistant alloy steel, and stainless steel under high-speed cutting conditions. As a result of earnest research to develop a coated tool having both high impact resistance, welding resistance, chipping resistance and wear resistance, Al and Ti, which are hard coating layers of conventional coated tools, are formed on the surface of the tool base. The lower nitride layer is a composite nitride layer of Al and Ti (hereinafter referred to as an (Al, Ti) N layer) containing a Ti component so that the Ti content in the total amount of 25 to 55 atomic%. Al having an average layer thickness of 0.5 to 5 μm, and an Al layer containing a Cr component such that the Cr content in the total amount of Al and Cr is 25 to 50 atomic%. Cr composite nitride layer (hereinafter referred to as (Al, Cr) N layer) ) With a one-layer average layer thickness of 0.1 to 1.0 μm, and a Cr nitride layer (hereinafter referred to as a CrN layer) is further formed thereon with a one-layer average layer thickness of 0.1 to 1.0 μm. By forming an alternating layer of two or more periods of (Al, Cr) N layers and CrN layers, the lower (Al, Ti) N layer has excellent wear resistance, heat resistance, and fracture resistance. In addition, the (Al, Cr) N layer constituting the alternate lamination of the upper layer exhibits excellent oxidation resistance and heat resistance, and the CrN layer exhibits excellent lubricity and welding resistance. By joining the (Al, Cr) N layer and the CrN layer, excellent impact resistance, chipping resistance, and crack resistance are exhibited, and further, a lower layer is formed between the tool base and the upper layer ( Synergy between the Al, Ti) N layer and the upper layer composed of alternating layers of the (Al, Cr) N layer and the CrN layer. The result becomes excellent chipping resistance (the toughness increased) so as to exert the wear resistance. Therefore, especially in high-speed cutting of difficult-to-cut materials that are heavily welded to the cutting edge during machining, even if the cutting edge becomes hot, it has excellent heat resistance, and as a result, chipping (small chipping) occurs at the cutting edge. New knowledge that the wear resistance is suppressed and excellent wear resistance is exhibited over a long period of time.

Furthermore, an average layer thickness of 0.5 to 5.0 μm (Al, 0.5 μm) containing a Ti component so that the Ti content in the total amount of Al and Ti is 25 to 55 atomic% on the surface of the tool base. An average layer thickness of 0.1 to 0.1 in which a Cr component is formed by vapor deposition and a Cr component is contained so that the Cr content in the total amount of Al and Cr is 25 to 50 atomic%. When the upper layer is composed of an alternating layered structure in which a 1.0 μm (Al, Cr) N layer and a CrN layer having an average layer thickness of 0.1 to 1.0 μm are alternately formed, the CrN layer has excellent lubricity. The (Al, Cr) N layer, which is formed by alternately laminating with this, exhibits excellent oxidation resistance and heat resistance. Therefore, even in cutting work with high heat generation, the CrN layer It has been found that excellent welding resistance is maintained.
That is, in high-speed cutting of difficult-to-cut materials such as titanium alloy and stainless steel, even if the cutting edge becomes hot, the (Al, Cr) N layer has insufficient welding resistance and is alternately laminated. As a result, the wear resistance with the work material is improved as a whole hard coating layer. As a result, chipping (slight chipping) is prevented from occurring at the cutting edge and excellent wear resistance over a long period of time. We obtained new knowledge that the sexuality is exhibited.
Furthermore, the present inventors have conducted detailed research focusing on the Young's modulus of the (Al, Ti) N layer and the (Al, Cr) N layer constituting the alternate lamination of the upper layer. For the (Al, Ti) N layer, the Young's modulus is not limited to the work material and cutting conditions in order to fully exhibit the wear resistance, heat resistance, and fracture resistance expected of the lower layer. When the Young's modulus is 400 to 550 GPa, the wear resistance, heat resistance, and fracture resistance of the (Al, Ti) N layer are more effectively exhibited. On the other hand, for the (Al, Cr) N layer as the upper layer, when the Young's modulus is a low Young's modulus of 150 to 300 GPa, the fracture resistance of the (Al, Cr) N layer is enhanced. It has been found that the damage form of steel or the like tends to have a life due to abnormal damage such as welding chipping, that is, it exhibits particularly excellent cutting performance in high-speed cutting of difficult-to-cut materials that are severely welded to the cutting edge during processing.
By combining several new findings as described above, each component has a synergistic effect, and it is difficult to predict from each component alone, and exhibits excellent cutting performance. It came to be completed.

The present invention has been made based on the research results,
“(1) In a surface-coated cutting tool in which a hard coating layer is formed on the surface of a tool base composed of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet,
The hard coating layer is
(A) having an average layer thickness of 0.5 to 5.0 μm, and
Composition formula: (Al _1-x Ti _x ) N (where x represents the content ratio of Ti in the total amount of Al and Ti, and the atomic ratio is 0.25 ≦ x ≦ 0.55) A lower layer comprising a composite nitride layer of Al and Ti satisfying and having a Young's modulus E of 400 GPa ≦ E ≦ 550 GPa;
(B) has an average layer thickness of 0.1 to 1.0 μm, and
Composition formula: (Al _1-y Cr _y ) N (where y represents the content ratio of Cr in the total amount of Al and Cr, and the atomic ratio is 0.25 ≦ y ≦ 0.50) A (Al, Cr) N layer consisting of a composite nitride layer of Al and Cr satisfying and having a Young's modulus E of 150 GPa ≦ E ≦ 300 GPa;
(C) a CrN layer having a single layer average layer thickness of 0.1 to 1.0 μm;
(B), (c) is composed of alternating laminations of two or more layers, the total average layer thickness is 1.2 times or more the average layer thickness of the lower layer, and 0.6-6 An upper layer that is 0.0 μm;
A surface-coated cutting tool characterized by comprising: "
It is characterized by.
In the present invention, the stacking cycle refers to the stacking of the (Al, Cr) N layer and the CrN layer as one cycle.

  Next, the reason why the numerical values of the constituent layers of the hard coating layer of the coated tool of the present invention are limited as described above will be described.

(A) Composition and average layer thickness of the (Al, Ti) N layer constituting the lower layer:
The Al component, which is a component of the (Al, Ti) N layer constituting the lower layer, improves the high-temperature hardness of the hard coating layer, and the Ti component has the effect of improving the high-temperature strength. When the x value indicating the ratio is less than 0.25 in the ratio to the total amount with Al (atomic ratio, the same applies hereinafter), the predetermined high-temperature strength cannot be ensured, which causes a decrease in wear resistance, On the other hand, if the x value indicating the Ti content exceeds 0.55, the Al content decreases relatively, and the high-temperature hardness required for high-speed cutting cannot be ensured. The x value was determined to be 0.25 to 0.55 because it would be difficult to prevent the occurrence of.
Further, if the average layer thickness of the (Al, Ti) N layer constituting the lower layer is less than 0.5 μm, it is insufficient to exhibit the excellent wear resistance of itself for a long time, When the average layer thickness exceeds 5 μm, chipping is likely to occur at the cutting edge portion in the high-speed cutting, so the average layer thickness was set to 0.5 to 5.0 μm.

(B) Composition of (Al, Cr) N layer constituting one of the alternately stacked layers in the upper layer:
The (Al, Cr) N layer made of a composite nitride of Al and Cr that constitutes one of the alternately stacked layers in the upper layer has excellent oxidation resistance and heat resistance, and also depends on its constituent Cr component. It comes to have excellent lubricity, and supplements high temperature hardness with Al component. Therefore, a low coefficient of friction is maintained even under high temperature cutting conditions, and excellent heat resistance is exhibited. However, the ratio of the y value indicating the Cr content to the total amount with Al (atomic ratio, the same applies hereinafter) If it is less than 0.25, it is not possible to expect welding resistance since lubricity cannot be ensured. On the other hand, if the y value indicating the Cr content exceeds 0.50, In addition, the Al content decreases, and not only the high-temperature hardness required for high-speed cutting of difficult-to-cut materials cannot be secured, but also the wear resistance is lowered, making it difficult to prevent chipping. Therefore, the y value was determined to be 0.25 to 0.50 (atomic ratio, the same applies hereinafter).

(C) Single layer average layer thickness of (Al, Cr) N layer and CrN layer constituting the alternate lamination in the upper layer:
The (Al, Cr) N layers constituting the alternating layers in the upper layer have excellent oxidation resistance and heat resistance, so that they exhibit excellent heat resistance, but the average layer thickness is less than 0.1 μm. However, it is insufficient to exhibit its excellent oxidation resistance and heat resistance over a long period of time. On the other hand, if the average layer thickness exceeds 1.0 μm, heat resistance is insufficient in high-speed cutting. Becomes apparent and chipping is likely to occur at the cutting edge, so the average layer thickness is set to 0.1 to 1.0 μm. In addition, the CrN layer has excellent welding resistance and has excellent lubricity due to its constituent Cr component. However, when the average layer thickness is less than 0.1 μm, the CrN layer has its own tangle. On the other hand, when the average layer thickness exceeds 1.0 μm, the lack of welding resistance becomes obvious in high-speed cutting, and the cutting edge portion becomes unclear. Since chipping easily occurs, the average layer thickness is determined to be 0.1 to 1.0 μm.
That is, the (Al, Cr) N layer provides oxidation resistance and heat resistance to the upper layer, and the CrN layer is provided to provide welding resistance and lubricity. If the layer thickness is in the range of 0.1 to 1.0 μm, the upper layer composed of the alternately laminated structure of each layer is as if it had excellent oxidation resistance, heat resistance, welding resistance, and lubricity. If each layer has an average layer thickness exceeding 1.0 μm, the (Al, Cr) N layer has insufficient oxidation resistance or heat resistance, or the CrN layer has welding resistance. Insufficient lubricity appears locally in the layer, and the upper layer as a whole cannot exhibit good characteristics as a single layer. It was determined to be 1.0 μm.

(D) Young's modulus of the lower (Al, Ti) N layer and the upper (Al, Cr) N layer:
When the (Al, Cr) N layer of the upper layer has a relatively low Young's modulus such that the Young's modulus is included in the range of 150 to 300 GPa, the amount of deformation of the film when external stress is applied increases and cracks occur. Therefore, the chipping resistance can be improved. Therefore, particularly excellent cutting performance is exhibited in high-speed cutting of difficult-to-cut materials that tend to have a life due to abnormal damage such as welding chipping, such as titanium alloy and stainless steel. On the other hand, if the Young's modulus of the upper (Al, Cr) N layer is lower than 150 GPa, it is not preferable because the wear resistance is remarkably lowered. Since it falls, the film is likely to collapse or peel off. Therefore, it is not preferable in high-speed cutting of difficult-to-cut materials such as titanium alloy steel and stainless steel. Therefore, in the present invention, the Young's modulus of the upper (Al, Cr) N layer is set to 150 to 300 GPa. On the other hand, the (Al, Ti) N layer of the lower layer is not limited to the work material and cutting conditions in order to sufficiently exhibit the wear resistance, heat resistance, and fracture resistance expected of the lower layer, When the Young's modulus is a relatively high Young's modulus of 400 to 550 GPa, the wear resistance, heat resistance, and fracture resistance of the (Al, Ti) N layer are more effectively exhibited. Therefore, in the present invention, the Young's modulus of the lower (Al, Ti) N layer is set to 400 to 550 GPa.

(E) The total average layer thickness of the upper layer and the layer thickness ratio of the lower layer and the upper layer:
The upper layer having an alternately laminated structure of (Al, Cr) N layers and CrN layers exhibits excellent oxidation resistance, heat resistance, welding resistance, and lubricity due to the synergistic effect of each layer as described above. However, if the total average layer thickness of the upper layer is less than 1.2 times the average layer thickness of the lower layer, the load concentrates on the upper layer during cutting, and the expected oxidation resistance, heat resistance, welding resistance, lubrication Sex is not played. On the other hand, if the total average layer thickness of the upper layer exceeds 6.0 μm, chipping is likely to occur, and the wear resistance is reduced. Therefore, the total average layer thickness of the upper layer was determined to be 0.6 to 6.0 μm and 1.2 times or more the average layer thickness of the lower layer.

The (Al, Ti) N layer, (Al, Cr) N layer, and CrN layer constituting the hard coating layer of the present invention are, for example, one type of physical vapor deposition apparatus schematically shown in FIG. A tool base is inserted into an arc ion plating apparatus, and the inside of the apparatus is heated to a temperature of, for example, 500 ° C. with a heater, and then the Al—Ti alloy, Al—Cr alloy or metal Cr having a predetermined composition is put into the apparatus. The cathode electrode (evaporation source) is arranged, and an arc discharge is generated between the anode electrode and the Al—Ti alloy as the cathode electrode (evaporation source), for example, under the condition of current: 110 A, and simultaneously reacts in the apparatus. Nitrogen gas is introduced as a gas to obtain a reaction atmosphere of, for example, 3 Pa. On the other hand, a predetermined target layer thickness is obtained by evaporating on the tool base for a predetermined time under the condition that a bias voltage of, for example, −100 V is applied. A lower layer (Al, Ti) N layer is formed. Then, arc discharge is alternately generated between the Al—Cr alloy as the anode electrode and the cathode electrode, for example, under the condition of current: 110 A, and simultaneously nitrogen gas is introduced into the apparatus as a reaction gas. On the other hand, a (Al, Cr) N layer having a predetermined target layer thickness is formed on the substrate by, for example, vapor deposition for a predetermined time under the condition that a bias voltage of −25 V is applied. . Furthermore, an arc discharge is generated between the metal Cr as the anode electrode and the cathode electrode, for example, under the condition of current: 110 A, and at the same time, nitrogen gas is introduced into the apparatus as a reaction gas to obtain a reaction atmosphere of, for example, 3 Pa. On the other hand, a CrN layer having a predetermined target layer thickness is formed on the tool base by, for example, vapor deposition for a predetermined time under the condition that a bias voltage of −55 V is applied. By repeatedly depositing these, the upper layer having a predetermined total target layer thickness consisting of an alternating layer of (Al, Cr) N layers and CrN layers having a predetermined target layer thickness is evaporated. A coating layer can be deposited.

  According to one aspect of the coated tool of the present invention, the hard coating layer has a lower layer made of an (Al, Ti) N layer and an upper layer made of an alternating laminate of an (Al, Cr) N layer and a CrN layer. When the Young's modulus of the (Al, Cr) N layer that constitutes the alternate lamination of the upper layer compared to the lower layer is a low Young's modulus, the hard coating layer has excellent high temperature hardness, heat resistance, high temperature strength, wear resistance As a whole, in addition to excellent high-temperature hardness, heat resistance, high-temperature strength, etc., it has excellent fracture resistance and welding resistance. , Titanium alloy, stainless steel, and other difficult-to-cut materials, with high heat generation, and high-speed cutting with high load, excellent weld resistance and fracture resistance, and excellent long-term resistance It exhibits chipping and wear resistance.

The arc ion plating apparatus used for forming the hard coating layer which comprises this invention coated tool is shown, (a) is a schematic plan view, (b) is a schematic front view. It is a schematic explanatory drawing of the conventional arc ion plating apparatus used in forming the hard coating layer which comprises the conventional coating tool. The schematic diagram of the layer structure of the hard coating layer of this invention is shown.

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

WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, TaN powder, and Co powder all having an average particle diameter of 1 to 3 μm are prepared as raw material powders. These raw material powders are blended into the composition shown in Table 1, wet mixed by a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. Medium, sintered at 1400 ° C. for 1 hour, and after sintering, tool bases A-1 to A-10 made of WC-base cemented carbide having an ISO standard / CNMG120408 insert shape were formed. .

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, all having an average particle diameter of 0.5 to 2 μm. Prepare powder, Co powder, and Ni powder, mix these raw material powders into the composition shown in Table 2, wet mix for 24 hours with a ball mill, dry, and press-mold into green compact at 100 MPa pressure Then, this green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, a tool substrate B made of TiCN base cermet having an ISO standard / CNMG120408 insert shape was used. -1 to B-6 were formed.

(A) Next, each of the tool bases A-1 to A-10 and B-1 to B-6 is ultrasonically cleaned in acetone and dried, and then the arc ion plating apparatus shown in FIG. It is mounted along the outer peripheral portion at a predetermined distance in the radial direction from the central axis on the inner rotary table, and cathode electrodes (evaporation sources) are arranged in three opposite directions across the rotary table. First, an Al—Ti alloy for forming a lower layer having a predetermined composition is disposed as a cathode electrode (evaporation source), and the second is an Al layer for forming an upper layer having a predetermined composition as a cathode electrode (evaporation source). -Cr alloy is arranged, and third, metal Cr for forming the upper layer is arranged as a cathode electrode (evaporation source),
(B) First, the inside of the apparatus is evacuated and kept at a vacuum of 0.1 Pa or less, the inside of the apparatus is heated to 500 ° C. with a heater, and then the direct current of −1000 V is applied to the tool base that rotates while rotating on the rotary table. A bias voltage is applied and a current of 100 A is passed between the cathode electrode and the anode electrode to generate an arc discharge, thereby bombarding the tool substrate surface,
(C) Next, nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere shown in Table 3, and a DC bias voltage shown in Table 3 is applied to the tool base that rotates while rotating on the rotary table. And applying an electric current of 120 A between the Al—Ti alloy of the cathode electrode and the anode electrode to generate an arc discharge, and on the surface of the tool base, the target composition, target layer thickness shown in Table 3, After vapor-depositing the (Al, Ti) N layer as the lower layer of Young's modulus, the arc discharge between the cathode electrode (evaporation source) and the anode electrode is stopped,
(D) Subsequently, a DC bias voltage shown in Table 3 is applied to the tool base that rotates while rotating on the rotary table while maintaining the atmosphere in the apparatus in the nitrogen atmosphere shown in Table 3, and the cathode electrode (evaporation) Source) Al—Cr alloy electrode or metal Cr electrode and an anode electrode are alternately supplied with a current of 120 A to generate an arc discharge, and the target composition, layer thickness, Young An upper layer of an alternate stacked structure having a stacking cycle and a total target layer thickness shown in Table 3 consisting of a (Al, Cr) N layer of a ratio and a CrN layer having a target layer thickness shown in Table 3;
A hard coating layer as schematically shown in FIG. 3 is formed on the tool substrate by vapor deposition according to (a) to (d), and a surface-coated insert (hereinafter referred to as the present invention-coated insert) 1 as the present invention-coated tool. ~ 16 were produced respectively.
The Young's modulus of each layer was controlled by controlling the bias voltage and the nitrogen partial pressure as described above. That is, the Young's modulus can be controlled to a low Young's modulus by forming the (Al, Cr) N layer constituting the alternately stacked upper layers by using a low bias voltage and a low nitrogen partial pressure. The Young's modulus of the underlayer (Al, Ti) N layer was controlled by controlling the bias voltage and the nitrogen partial pressure as described above. That is, it can control to 400-550 GPa by forming into a film in the range of -20-150V and 0.5-9.0Pa.
The Young's modulus was measured by a nanoindentation method using a nanoindenter (trademark of MTS Systems). The results are shown in Table 3.

  For comparison purposes, surface coated inserts (hereinafter referred to as comparative coated inserts) 1 to 8 as comparative coated tools shown in Table 4 were produced in the same manner as in the above examples. Here, the comparative coating insert 1 has a hard coating layer made of a single layer of (Al, Ti) N layer, and the comparative coating insert 2 has a lower layer made of (Al, Ti) N layer and (Al , Cr) N has a hard coating layer composed of an upper layer composed of a single layer, and comparative coating inserts 3 to 8 are composed of a lower layer composed of an (Al, Ti) N layer and an (Al, Cr) N layer. A hard coating layer consisting of alternating layers of CrN layers and CrN layers, but the upper layer Young's modulus, single layer target thickness, or total target layer thickness deviates from the numerical range defined in the present invention. To do.

Next, with the various coated inserts, all of the present invention coated inserts 1 to 16 and comparative coated inserts 1 to 8 in a state where all the tool inserts are screwed to the tip of the tool steel tool with a fixing jig.
Work material: JIS / SUS304 (HB220) round bar,
Cutting speed: 145 m / min. ,
Cutting depth: 2.5mm,
Feed: 0.2 mm / rev. ,
Cutting time: 5 minutes
(Continuous cutting speed and feed are 120 m / min. And 0.2 mm / rev., Respectively)
Work material: Ti-6Al-4V alloy (HB260) round bar,
Cutting speed: 60 m / min. ,
Incision: 2 mm,
Feed: 0.2 mm / rev. ,
Cutting time: 5 minutes
Wet continuous high-speed cutting test of Ti alloy under the following conditions (cutting condition B) (normal cutting speed and feed are 40 m / min. And 0.2 mm / rev., Respectively),
Work material: JIS G4901 (HB190) round bar,
Cutting speed: 75 m / min. ,
Cutting depth: 2mm,
Feed: 0.2 mm / rev. ,
Cutting time: 5 minutes
Wet continuous high-speed cutting test of nickel alloy under the following conditions (cutting condition C) (normal cutting speed and feed are 50 m / min. And 0.2 mm / rev., Respectively),
The flank wear width of the cutting edge was measured in any high-speed cutting test. The measurement results are shown in Tables 5 and 6.

As in Example 1, all of WC powder, TiC powder, ZrC powder, VC powder, TaC powder, NbC powder, Cr ₃ C ₂ powder, TiN powder, TaN powder, and Co having an average particle diameter of 1 to 3 μm. A raw material powder composed of powder is blended in the composition shown in Table 1, wet mixed by a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 100 MPa. Medium, sintered at 1400 ° C. for 1 hour to form a round tool sintered body for forming a tool base having a diameter of 13 mm. Further, the round bar sintered body is cut by grinding. Manufacture of WC-base cemented carbide tool bases (end mills) A-1 to A-10 having a blade part diameter x length of 10 mm x 22 mm and a 4-blade square shape with a twist angle of 30 degrees did.

  Then, the surfaces of these tool bases (end mills) A-1 to A-10 were ultrasonically cleaned in acetone and dried, and then charged into the arc ion plating apparatus shown in FIG. 1, the lower layer composed of the (Al, Ti) N layer having the target composition, target layer thickness, and Young's modulus shown in Table 7 with the bias voltage and nitrogen partial pressure shown in Table 7; Table 7 consisting of (Al, Cr) N layer with target composition, single layer thickness, Young's modulus shown in Table 7 and CrN layer with single layer thickness shown in Table 7 with the indicated bias voltage and nitrogen partial pressure The surface coating cemented carbide end mill of the present invention as the coating tool of the present invention (hereinafter referred to as the following) is formed by vapor-depositing and forming a hard coating layer composed of the lamination cycle shown in FIG. This is called the coated end mill of the present invention. 0 was prepared, respectively.

For comparison purposes, surface-coated end mills (hereinafter referred to as comparative coated end mills) 1 to 5 as comparative coated tools shown in Table 8 were produced in the same manner as in the above examples. Here, the comparative coated end mill 1 has a hard coating layer made of a single layer of (Al, Ti) N layer, and the comparative coated end mill 2 has a lower layer made of (Al, Ti) N layer and (Al , Cr) N has a hard coating layer composed of a single upper layer, and comparative coated end mills 3 to 5 have a lower layer composed of an (Al, Ti) N layer and an (Al, Cr) N layer. A hard coating layer consisting of alternating layers of CrN layers and CrN layers, but the upper layer Young's modulus, single layer target thickness, or total target layer thickness deviates from the numerical range defined in the present invention. To do.
Next, for the present invention coated end mills 1-10 and comparative coated end mills 1-5,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 (HB200) plate material,
Cutting speed: 130 m / min. ,
Groove depth (cut): 15 mm,
Table feed: 310 mm / min. ,
(High cutting speed and table feed are 90 m / min. And 280 mm / min., Respectively)
Work material—planar dimensions: 100 mm × 250 mm, thickness: 50 mm Ti-6Al-4V alloy (HB230) plate,
Cutting speed: 90 m / min. ,
Groove depth (cut): 15 mm,
Table feed: 120 mm / min. ,
Wet high-speed grooving test of Ti alloy under the following conditions (cutting condition E) (normal cutting speed and table feed are 35 m / min. And 95 mm / min., Respectively),
Work material-Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS G4902 (HRB87) plate material,
Cutting speed: 60 m / min. ,
Groove depth (cut): 15 mm,
Table feed: 100 mm / min. ,
Wet high-speed grooving test of nickel alloy under the following conditions (cutting condition F) (normal cutting speed and table feed are 35 m / min. And 85 mm / min., Respectively),
In each high-speed groove cutting test, the cutting groove length was measured until the flank wear width of the outer peripheral edge of the cutting edge reached 0.1 mm, which is a guide for the service life. The measurement results are also shown in Tables 7 and 8, respectively.

  The round bar sintered body with a diameter of 13 mm manufactured in Example 2 was used, and from this round bar sintered body, the dimensions of the groove forming part diameter × length were 8 mm × 22 mm and the twist angle by grinding. WC-base cemented carbide tool bases (drills) A-1 to A-10 having a 30-degree two-blade shape were produced, respectively.

  Next, the cutting edges of these tool bases (drills) A-1 to A-10 are subjected to honing, ultrasonically cleaned in acetone, and dried to the arc ion plating apparatus shown in FIG. In the same manner as in Example 1, using the bias voltage and nitrogen partial pressure shown in Table 9, the lower layer composed of the (Al, Ti) N layer having the target composition and target layer thickness shown in Table 9 Then, using the bias voltage and nitrogen partial pressure shown in Table 9, the (Al, Cr) N layer having the target composition and the target layer thickness shown in Table 9 and the CrN layer having the target layer thickness shown in Table 9 are used. The surface coated carbide drill of the present invention as the coated tool of the present invention is formed by vapor-depositing a hard coating layer composed of an upper layer having an alternate laminated structure of the lamination period and total target layer thickness shown in Table 9 (Hereinafter referred to as the coated drill of the present invention) ) 1 to 10 were prepared, respectively.

  For comparison purposes, surface-coated drills (hereinafter referred to as comparative coated drills) 1 to 5 as comparative coated tools shown in Table 10 were produced by the same method as in the above-described examples. Here, the comparative coated drill 1 has a hard coating layer made of a single layer of (Al, Ti) N layer, and the comparative coated drill 2 has a lower layer made of (Al, Ti) N layer and (Al , Cr) N has a hard coating layer composed of a single upper layer, and comparative coated drills 3 to 5 have (Al, Ti) N lower layer and (Al, Cr) N A hard coating layer consisting of alternating layers of CrN layers and CrN layers, but the upper layer Young's modulus, single layer target thickness, or total target layer thickness deviates from the numerical range defined in the present invention. To do.

Next, for the present invention coated drills 1-10 and comparative coated drills 1-5,
Work material-planar dimensions: 100 mm × 250 mm, thickness: 50 mm JIS / SUS304 (HB200) plate material,
Cutting speed: 110 m / min. ,
Feed: 0.3 mm / rev. ,
Hole depth: 5mm,
Wet high-speed drilling test of stainless steel under the following conditions (cutting condition G) (normal cutting speed and feed are 70 m / min. And 0.2 mm / rev., Respectively),
Work material-planar dimensions: 100 mm x 250 mm, thickness: 50 mm Ti-6Al-4V alloy (HB280) plate,
Cutting speed: 70 m / min. ,
Feed: 0.2 mm / rev. ,
Hole depth: 5mm,
Wet high-speed drilling test of Ti alloy under the following conditions (cutting condition H) ((normal cutting speed and feed are 40 m / min. And 0.15 mm / rev., Respectively),
Work material-Plane dimensions: 100 mm x 250 mm, thickness: 50 mm JIS G4902 (HRB87) plate material,
Cutting speed: 60 m / min. ,
Feed: 0.2 mm / rev. ,
Hole depth: 5mm,
Wet high speed drilling test of nickel alloy under the following conditions (cutting condition I) (normal cutting speed and feed are 45 m / min. And 0.1 mm / rev., Respectively),
In each wet high-speed drilling test (using water-soluble cutting oil), the number of drilling processes until the flank wear width of the tip cutting edge surface reached 0.3 mm was measured. The measurement results are also shown in Table 9 and Table 10, respectively.

  As a result, this invention coated insert 1-16 as this invention coated tool, this invention coated end mill 1-10, and the lower layer which comprises the hard coating layer of this invention coated drill 1-10 are comprised (Al , Ti) N layer and upper layer constituting an alternate stack of (Al, Cr) N layer and CrN layer composition, comparative coated inserts 1-8 as comparative coated tools, comparative coated end mills 1-5, and comparison Dispersion of the composition of the (Al, Ti) N layer and the upper layer constituting the lower layer of the coated drills 1 to 5 using the transmission electron microscope. When measured by X-ray analysis, each showed substantially the same composition as the target composition.

  Moreover, when the average layer thickness of each layer which comprises the said hard coating layer was cross-sectional measured using the scanning electron microscope, all showed the average layer thickness (average value of five places) substantially the same as target layer thickness. .

  From the results shown in Tables 3 to 10, the coated tool of the present invention has excellent high-temperature hardness in a state in which the lower layer (Al, Ti) N layer having a high Young's modulus is firmly adhered to the surface of the tool substrate. It has heat resistance and high temperature strength, and the alternate lamination of the low Young's modulus (Al, Cr) N layer and CrN layer that constitute the upper layer has impact resistance, chipping resistance, and crack resistance. This ensures excellent wear resistance over a long period of time without chipping even when high-speed cutting of difficult-to-cut materials such as titanium alloy and stainless steel is ensured. On the other hand, even if the hard coating layer is composed of only the (Al, Ti) N layer or the upper layer has an alternate lamination of (Al, Cr) N layers and CrN layers, (Al, Cr) Young's modulus of N layer, (Al, Cr) N layer and Cr In the comparative coated tool in which the average layer thickness of the layers deviates from the numerical range defined in the present invention, in all high-speed cutting of difficult-to-cut materials, the work material (difficult-to-cut material) and the chips and the hard coating layer It is clear that since the adhesiveness and reactivity of this material are further increased, chipping occurs at the cutting edge and the service life is reached in a relatively short time.

  As described above, the coated tool of the present invention has excellent wear resistance and resistance not only to cutting of general work materials, but also to high-speed cutting of difficult-to-cut materials such as titanium alloy and stainless steel. Demonstrates flawlessness and exhibits excellent cutting performance over a long period of time, so it can sufficiently satisfy automation of cutting equipment, labor saving and energy saving of cutting, and cost reduction. .

Claims (1)

In a surface-coated cutting tool formed by forming a hard coating layer on the surface of a tool base composed of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet,
The hard coating layer is
(A) having an average layer thickness of 0.5 to 5.0 μm, and
Composition formula: (Al _1-x Ti _x ) N (where x represents the content ratio of Ti in the total amount of Al and Ti, and the atomic ratio is 0.25 ≦ x ≦ 0.55) A lower layer composed of a composite nitride layer of Al and Ti satisfying and having a Young's modulus E of 400 GPa ≦ E ≦ 550 GPa;
(B) has an average layer thickness of 0.1 to 1.0 μm, and
Composition formula: (Al _1-y Cr _y ) N (where y represents the content ratio of Cr in the total amount of Al and Cr, and the atomic ratio is 0.25 ≦ y ≦ 0.50) A (Al, Cr) N layer comprising a composite nitride layer of Al and Cr satisfying and having a Young's modulus E of 150 GPa ≦ E ≦ 300 GPa;
(C) a CrN layer having a single layer average layer thickness of 0.1 to 1.0 μm;
An upper layer comprising (b) and (c) two or more alternating layers, the total average layer thickness being 1.2 times or more of the lower layer, and 0.6 to 6.0 μm A surface-coated cutting tool comprising: