JP4702538B2 - Surface coated cutting tool with excellent wear resistance due to high hard coating layer in high speed cutting of high hardness steel - Google Patents

Description

  This invention has a high heat resistance such as alloy tool steels and hardened materials for bearing steels, in which the hard coating layer has excellent heat resistance, and also has high-temperature hardness and high-temperature strength, and thus particularly excellent heat resistance is required. Even when used in high-speed cutting with high heat generation such as hard steel, the surface of a carbide substrate made of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet that exhibits excellent wear resistance or high The present invention relates to a surface-coated cutting tool in which a hard coating layer is formed on the surface of a speed tool steel substrate.

  In general, surface-coated cutting tools include a throw-away tip that is detachably attached to the tip of a cutting tool for turning and planing of various steels and cast irons, and drilling of the work material. There are drills and miniature drills used for processing, etc., and solid type end mills used for chamfering, grooving, shoulder processing, etc. of the work material. A slow-away end mill tool that performs cutting work in the same manner as a type end mill is known.

Also, as one of the surface-coated cutting tools, for example, on the surface of a cemented carbide substrate composed of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet, Having a single phase structure, and
_{Formula: [Ti 1- (X + Y} ) Al X Si Y] N ( provided that an atomic ratio, X is from .50 to 0.65, Y represents a 0.01-0.10)
Surface coating formed by vapor-depositing a hard coating layer composed of a composite nitride of Ti, Al and Si [hereinafter referred to as (Ti, Al, Si) N] layer satisfying the requirements of 0.1 to 20 μm. A cemented carbide tool is known. In such a conventional surface-coated cemented carbide tool, the (Ti, Al, Si) N layer constituting the hard coating layer is hardened at a high temperature by the constituent component Al. It is also known that the high temperature strength and the heat resistance are improved by the Si.

Furthermore, the above-mentioned surface-coated carbide tool is loaded with the above-mentioned carbide substrate in an arc ion plating apparatus which is one of physical vapor deposition apparatuses schematically shown in FIG. For example, a cathode electrode (evaporation source) in which a Ti—Al—Si alloy having a composition corresponding to the composition of the (Ti, Al, Si) N layer, which is a hard coating layer, is heated to a temperature of 500 ° C. For example, an arc discharge is generated between the anode electrode and the anode electrode under the condition of current: 90A, and simultaneously nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of 2 Pa, for example. For example, it is also known that it is produced by depositing a hard coating layer composed of the (Ti, Al, Si) N layer on the surface of the cemented carbide substrate under the condition that a bias voltage of −100 V is applied.
Japanese Patent No. 2793773

In recent years, the performance of cutting devices has been dramatically improved. On the other hand, there is a strong demand for labor saving and energy saving and further cost reduction for cutting, and with this, cutting tends to be faster. In the case of surface coated carbide tools, when this is used to cut steel or cast iron under normal cutting conditions, there is no problem if the composition is selected according to the cutting conditions. Used for cutting high hardness steels with high heat of Vickers hardness (C scale) such as hardened steel and bearing steel under high-speed cutting conditions with high heat generation. In some cases, particularly due to the lack of heat resistance of the hard coating layer, the progress of wear is extremely fast, so that the service life is reached in a relatively short time.

In view of the above, the present inventors have developed a surface-coated cutting tool that exhibits excellent wear resistance with a hard coating layer particularly in high-speed cutting of high-hardness steel. As a result of conducting research by focusing on the (Ti, Al, Si) N layer constituting the hard coating layer of hard tools,

(a) In the (Ti, Al, Si) N layer constituting the hard coating layer, the heat resistance is improved by increasing the content ratio of the Si component, but 1 in the conventional (Ti, Al, Si) N layer described above. When the Si content is about 10 atomic%, the high heat resistance required for high-speed cutting of high hardness steel cannot be ensured. In order to satisfy these requirements satisfactorily, the above 1-10 atomic% In order to use a (Ti, Al, Si) N layer containing 20 to 35 atomic% of Si component, which is much more than 20 to 35 atomic%, as a hard coating layer, practically, It is necessary to contain a predetermined amount of Ti to ensure a predetermined high temperature strength. In this case, however, the content ratio of the Al component is unavoidably low, and as a result, the high temperature hardness is extremely low. thing.

(B) The (Ti, Al, Si) N layer (hereinafter referred to as the thin layer A) in which the Si content in (a) is increased to 20 to 35 atomic% to improve heat resistance, The (Ti, Al, Si) N layer (hereinafter referred to as the thin layer B) having a relatively high Al content and a predetermined relatively high high-temperature hardness, although the Si content is relatively low. When the layers are alternately laminated in a state where each layer has an average layer thickness of 5 to 20 nm (nanometers), the (Ti, Al, Si) N layer of this alternately laminated structure is a thin layer A containing high Si. To have both excellent heat resistance and a predetermined high-temperature hardness phase of the thin layer B having a relatively high Al content.
Here, the composition formulas of the thin layer A and the thin layer B are as follows.
Composition formula of thin layer A: [Ti _{1- (E + F)} Al _E Si _F ] N (however, in atomic ratio, E represents 0.15 to 0.30, F represents 0.20 to 0.35)
Composition formula of the thin layer B: [Ti _{1- (M + N)} Al _M Si _N ] N (however, in atomic ratio, M is 0.50 to 0.65, and N is 0.01 to 0.10)

(C) The (Ti, Al, Si) N layer having the alternately laminated structure of the thin layer A and the thin layer B of (b) above has excellent heat resistance and predetermined characteristics required for high-speed cutting of high hardness steel. Although it does not have a sufficiently high temperature hardness yet, it is provided as an upper layer of the hard coating layer, while the lower layer is insufficient in heat resistance, but relative (Ti, Al, Si) N layer having a composition corresponding to the above-mentioned conventional hard coating layer having a high Al component content and excellent high-temperature hardness,

Composition formula: [Ti _{1− (X + Y)} Al _X Si _Y ] N (wherein, X is 0.50 to 0.65 and Y is 0.01 to 0.10 in atomic ratio) (Ti, Al, Si) N layer of single phase structure,
With this structure, the hard coating layer consisting of the upper layer and the lower layer has excellent heat resistance and excellent high temperature hardness and high temperature strength. The coated cemented carbide tool should exhibit excellent wear resistance over a long period of time without chipping even in high-speed cutting of high-hardness steel with high heat generation.

The research results shown in (a) to (c) above were obtained.

This invention was made based on the above research results,

On the surface of a cemented carbide substrate made of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet, or on the surface of a high-speed tool steel substrate,
(A) Both are composed of an upper layer and a lower layer made of a composite nitride of Ti, Al, and Si, the upper layer has an average layer thickness of 0.5 to 1.5 μm, and the lower layer has an average layer thickness of 2 to 6 μm. Have
(B) Each of the upper layers has an alternately laminated structure of thin layers A and B each having an average layer thickness of 5 to 20 nm (nanometer),
The thin layer A is
Ti satisfying the composition formula: [Ti _{1− (E + F)} Al _E Si _F ] N (wherein E is 0.15 to 0.30 and F is 0.20 to 0.35 in atomic ratio) A composite nitride layer of Al and Si;
The thin layer B is
_{Formula: [Ti 1- (M + N} ) Al M Si N] N ( provided that an atomic ratio, M is from .50 to 0.65, N denotes the 0.01-0.10) and Ti which satisfies A composite nitride layer of Al and Si,
(C) the lower layer has a single phase structure;
_{Formula: [Ti 1- (X + Y} ) Al X Si Y] N ( provided that an atomic ratio, X is from .50 to 0.65, Y denotes the 0.01-0.10) and Ti which satisfies A composite nitride layer of Al and Si;
It is characterized by a surface-coated cutting tool that exhibits excellent wear resistance in high-speed cutting of high-hardness steel formed by vapor-depositing a hard coating layer made of

Next, the reason why the numerical values of the hard coating layer of the surface-coated cutting tool of the present invention are limited as described above will be described.
(A) Composition formula and average layer thickness of the hard coating layer constituting the lower layer Hard coating layer (Ti, Al, Si) The Al component in the N layer improves high temperature hardness, while the Ti component has high temperature strength. In addition, the Si component has an effect of improving heat resistance, and the lower layer increases the Al component content to provide high high-temperature hardness. However, the X value indicating the Al content is Ti and Si. If it is less than 0.50 in terms of the total amount (atomic ratio, the same shall apply hereinafter), the proportion of Ti will be relatively high, ensuring excellent high-temperature hardness required for high-speed cutting of high-hardness steel. However, when the X value indicating the proportion of Al exceeds 0.65, the proportion of Ti is relatively decreased, and the high temperature strength is increased. Decreases rapidly, resulting in chipping (slight chipping) Therefore, the X value was set to 0.50 to 0.65.
Further, the Y value indicating the proportion of Si is the proportion of the total amount of Ti and Al. If the Y value is less than 0.01, the predetermined heat resistance cannot be ensured, while the Y value exceeds 0.10. The Y value was determined to be 0.01 to 0.10 because a clear lowering tendency appears in the high-temperature strength.
Furthermore, if the average layer thickness is less than 2 μm, it is impossible to impart its own high-temperature hardness to the hard coating layer over a long period of time, resulting in a short tool life, while if the average layer thickness exceeds 6 μm, Since chipping is likely to occur, the average layer thickness was determined to be 2 to 6 μm.

(B) Composition formula of the hard coating layer constituting the thin layer A of the upper layer The Si component in (Ti, Al, Si) N of the thin layer A of the upper layer improves the heat resistance, thereby increasing the high heat generation. It is included for the purpose of adapting to high-speed cutting of hardened steel. Therefore, the F value indicating the content ratio is the ratio of the total amount of Ti and Al. Excellent heat resistance cannot be ensured. On the other hand, if the F value exceeds 0.35, the high-temperature strength decreases rapidly, which causes a decrease in the high-temperature strength of the entire upper layer, and chipping is likely to occur. Therefore, the F value was set to 0.20 to 0.35.
Further, the E value indicating the proportion of Al is the proportion of the total amount of Ti and Si, and if it is less than 0.15, the minimum high-temperature hardness cannot be ensured, causing wear promotion, while the E If the value exceeds 0.30, the high-temperature strength decreases and causes chipping, so the E value was set to 0.15 to 0.30.

(C) Composition formula of the hard coating layer constituting the thin layer B of the upper layer The thin layer B is an upper layer composed of an alternating laminated structure of the thin layer A and the thin layer B. The main purpose is to compensate for (high temperature hardness).

As already mentioned, the thin layer A of the upper layer is intended to increase the content ratio of the Si component and improve its heat resistance, but the upper layer is also required to have a predetermined high-temperature strength. In order to ensure, it is necessary to contain a predetermined amount of Ti in the thin layer A. If it does so, the content rate of Al in the thin layer A will have to decrease, As a result, the high temperature hardness of the thin layer A becomes inadequate, and it leads to the fall of abrasion resistance by extension.
Therefore, in the thin layer B of the upper layer, the content ratio of the Si component is relatively low as compared with the thin layer A, while the content ratio of the Al component is maintained relatively high, An upper portion having a high high temperature hardness and compensating for the shortage of the high temperature hardness of the adjacent thin layer A, so that the thin layer A has excellent heat resistance and the thin layer B has a predetermined high temperature hardness. Form a layer.
When the M value indicating the Al content ratio in the composition formula of the thin layer B is less than 0.50, the Al content ratio becomes too small to ensure a predetermined high-temperature hardness, and as a result, wear progresses. On the other hand, if the M value exceeds 0.65, the content ratio of the Ti component is relatively reduced, and the high-temperature strength of the upper layer is inevitably reduced, which may cause chipping. Therefore, the M value was determined to be 0.50 to 0.65.

Further, the N value indicating the proportion of Si occupies the total amount of Ti and Al. If the N value is less than 0.01, the heat resistance of the entire upper layer is inevitably deteriorated, while the N value exceeds 0.10. The N value was determined to be 0.01 to 0.10 because the high-temperature strength decreased and chipping was likely to occur.

(D) Single layer average layer thickness of thin layer A and thin layer B of the upper layer Thin layer A and thin layer B of the upper layer, and if each single layer average layer thickness is less than 5 nm, each thin layer is of the above composition It is difficult to form clearly, and as a result, the desired excellent heat resistance and a predetermined high-temperature hardness cannot be ensured in the upper layer, and each average layer thickness exceeds 20 nm. Defects of the thin layer, that is, if the thin layer A is insufficient in high-temperature hardness, if it is thin layer B, insufficient heat resistance appears locally in the layer, and this causes wear to proceed rapidly. Therefore, the average layer thickness of each layer was determined to be 5 to 20 nm.

That is, the thin layer B is provided to reinforce the characteristics of the thin layer A, but if the average layer thickness of each of the thin layer A and the thin layer B is within the range of 5 to 20 nm, the thin layer B is thin. The upper layer composed of the alternately laminated structure of the layer A and the thin layer B functions as if it is a single layer having excellent heat resistance, predetermined high temperature hardness and excellent high temperature strength. When the average layer thickness of each of A and thin layer B exceeds 20 nm, the high temperature hardness of thin layer A or the heat resistance of thin layer B appears locally in the layer, and the upper layer Since good characteristics as a single layer cannot be exhibited as a whole, the average layer thickness of each of the thin layers A and B was determined to be 5 to 20 nm.
Excellent heat resistance, high temperature hardness, and high temperature strength can be obtained by forming an upper layer having an alternate layer structure in which the average layer thickness of the thin layers A and B is in the range of 5 to 20 nm on the lower layer surface. A hard coating layer is obtained.

(E) Average layer thickness of the upper layer If the average layer thickness of the entire upper layer is less than 0.5 μm, it is not possible to impart the excellent heat resistance of the upper layer and the predetermined high temperature hardness to the hard coating layer over a long period of time. On the other hand, if the average layer thickness of the entire upper layer exceeds 1.5 μm, chipping is likely to occur. Therefore, the average layer thickness is set to 0.5 to 1.5 μm.

  In the surface-coated cutting tool according to the present invention, the hard coating layer is composed of a (Ti, Al, Si) N layer, and the upper layer of the hard coating layer is excellent by adopting an alternate laminated structure of the thin layer A and the thin layer B. Because it has heat resistance and a predetermined high temperature hardness, and the lower layer of the single phase structure has an excellent high temperature hardness, even in high-speed cutting of high hardness steel with high heat generation, the hard coating layer It exhibits excellent wear resistance over a long period of time without occurrence of chipping.

  Next, the surface-coated cutting 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, after sintering, WC-based carbide with honing of R: 0.03 on the cutting edge and chip shape of ISO standard CNMG120408 Alloy carbide substrates A-1 to A-10 were formed.

In addition, as raw material powders, all are TiCN (weight ratio TiC / TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder 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 then pressed into a compact at a pressure of 100 MPa. The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour, and after sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to obtain ISO standard / CNMG120408. The carbide substrates B-1 to B-6 made of TiCN base cermet having the following chip shape were formed.

(A) Next, each of the above carbide substrates A-1 to A-10 and B-1 to B-6 was ultrasonically cleaned in acetone and dried, and then the arc ion plate shown in FIG. Attached along the outer peripheral portion at a predetermined distance in the radial direction from the central axis on the rotary table in the coating apparatus, and used as a cathode electrode (evaporation source) on one side with the target compositions shown in Tables 3 and 4, respectively. As the upper layer Ti-Al-Si alloy for forming the thin layer A having the corresponding component composition and the cathode electrode (evaporation source) on the other side, the component compositions corresponding to the target compositions shown in Tables 3 and 4 are also used. The upper layer thin layer B and the lower layer forming Ti-Al-Si alloy are disposed opposite to each other with the rotary table interposed therebetween,
(B) First, the inside of the apparatus is evacuated and maintained at a vacuum of 0.1 Pa or less, and the inside of the apparatus is heated to 400 ° C. with a heater, and then the carbide substrate that rotates while rotating on the rotary table is set to −1000 V And applying a current of 100 A between the thin layer B and Ti-Al-Si alloy for forming the lower layer and the lower layer and the anode electrode to generate arc discharge. Bombarded with Ti-Al-Si alloy,
(C) Introducing nitrogen gas as a reaction gas into the apparatus to make a reaction atmosphere of 3 Pa, applying a DC bias voltage of −100 V to a carbide substrate rotating while rotating on the rotary table, and An arc discharge is generated by passing a current of 100 A between the layer B and the Ti-Al-Si alloy for forming the lower layer and the anode electrode, so that the target compositions shown in Tables 3 and 4 are formed on the surface of the carbide substrate. And a (Ti, Al, Si) N layer having a single phase structure with a target layer thickness is deposited as a lower layer of the hard coating layer,

(D) Next, the flow rate of nitrogen gas as a reaction gas introduced into the apparatus is adjusted to a reaction atmosphere of 2 Pa, and a DC bias voltage of −100 V is applied to the carbide substrate rotating while rotating on the rotary table. In the applied state, a predetermined current in the range of 50 to 200 A is passed between the cathode electrode and the anode electrode of the Ti-Al-Si alloy for forming the thin layer A to generate arc discharge, and the carbide A thin layer A having a predetermined layer thickness is formed on the surface of the substrate, and after the thin layer A is formed, the arc discharge is stopped. Instead, the cathode electrode of the thin layer B and the lower layer forming Ti—Al—Si alloy Similarly, a predetermined current in the range of 50 to 200 A is passed between the anode electrodes to generate arc discharge to form a thin layer B having a predetermined layer thickness. Then, the arc discharge is stopped and the thin layer A is formed again. Ti-Al-Si alloy The formation of thin layer A by arc discharge between the cathode electrode and the anode electrode and the formation of thin layer B by arc discharge between the cathode electrode and the anode electrode of the thin layer B and Ti-Al-Si alloy for forming the lower layer are alternately performed. Thus, an upper layer composed of alternately laminated thin layers A and B having a target composition and a target layer thickness of one layer along the layer thickness direction is similarly formed on the surface of the cemented carbide substrate. By carrying out vapor deposition with the overall target layer thicknesses shown in Tables 3 and 4, the present invention surface-coated carbide throwaway tip (hereinafter referred to as the present invention coated carbide tip) 1 to 1 as the present invention coated carbide tool. 16 were produced respectively.

  For the purpose of comparison, these carbide substrates A-1 to A-10 and B-1 to B-6 were ultrasonically cleaned in acetone and dried, respectively, and the arc ion plating apparatus shown in FIG. A Ti—Al—Si alloy having a component composition corresponding to the target composition shown in Table 5 was attached as a cathode electrode (evaporation source), and the apparatus was first evacuated to 0.1 Pa. While maintaining the following vacuum, the inside of the apparatus was heated to 400 ° C. with a heater, a DC bias voltage of −1000 V was applied to the cemented carbide substrate, and the Ti—Al—Si alloy and anode electrode of the cathode electrode were applied. A current of 100 A was passed between them to generate an arc discharge, so that the surface of the cemented carbide substrate was bombarded with the Ti—Al—Si alloy, and then nitrogen gas was introduced into the apparatus as a reactive gas, and 3 Pa of And a bias voltage applied to the cemented carbide substrate is lowered to -100 V to generate an arc discharge between the cathode electrode and the anode electrode of the Ti-Al-Si alloy. Each of A-1 to A-10 and B-1 to B-6 has a (Ti, Al, Si) N layer having a single-phase structure having a target composition and a target layer thickness shown in Table 5. By forming the hard coating layer by vapor deposition, conventional surface-coated carbide throw-away tips (hereinafter referred to as conventional coated carbide tips) 1 to 16 as conventional coated carbide tools were produced, respectively.

Next, the coated carbide tips 1-16 of the present invention and the conventional coated carbide tip 1 in the state where each of the various coated carbide tips is screwed to the tip of the tool steel tool with a fixing jig. About ~ 16
Work material: JIS / SKD61 hardened material (hardness: HRC56) round bar,
Cutting speed: 80 m / min. ,
Cutting depth: 0.8 mm,
Feed: 0.08 mm / rev. ,
Cutting time: 5 minutes,
Dry continuous high-speed cutting test of alloy tool steel under the conditions (cutting condition A) (normal cutting speed is 40 m / min.),
Work material: JIS / SUJ2 hardened material (hardness: HRC56), 4 longitudinally spaced round bars with equal intervals in the length direction,
Cutting speed: 40 m / min. ,
Cutting depth: 1.0 mm,
Feed: 0.1 mm / rev. ,
Cutting time: 5 minutes,
Dry intermittent high-speed cutting test of the bearing steel under the conditions (referred to as cutting condition B) (normal cutting speed is 20 m / min.),
Work material: JIS · SKD11 quenching material (hardness: HRC57) 4 longitudinally spaced round bars with equal intervals in the length direction,
Cutting speed: 45 m / min. ,
Cutting depth: 0.6 mm,
Feed: 0.1 mm / rev. ,
Cutting time: 5 minutes,
A dry continuous high-speed cutting test (normal cutting speed is 20 m / min.) Of the alloy tool steel under the above conditions (referred to as 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 6.

(A) As raw material powder, medium coarse WC powder having an average particle size of 5.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, NbC powder of 1.2 μm, 2 μm ZrC powder, 2.3 μm Cr ₃ C ₂ powder, 1.5 μm VC powder, 1.0 μm (Ti, W) C [by mass ratio, TiC / WC = 50/50] powder, Co powder of 1.8 μm was prepared, and these raw material powders were blended in the blending composition shown in Table 7, respectively, and added with wax, ball milled in acetone for 24 hours, dried under reduced pressure, and then pressure of 100 MPa Are pressed into various green compacts of a predetermined shape, and these green compacts are heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a heating rate of 7 ° C./min in a vacuum atmosphere of 6 Pa. And after holding at this temperature for 1 hour, As a result, three types of cemented carbide substrate-forming round bar sintered bodies having diameters of 8 mm, 13 mm, and 26 mm were formed. In the combination shown in the above, the diameter × length of the cutting edge is 6 mm × 13 mm, 10 mm × 22 mm, and 20 mm × 45 mm, respectively, and each has a four-blade square shape with a twist angle of 30 degrees. Cemented carbide substrates (end mills) C-1 to C-8 were produced, respectively.
(B) Also, the diameter of the cutting edge part x in the combinations shown in Table 7 by machining from three types of high-speed tool steel (JIS / SKH55) materials with a diameter of 8 mm, 13 mm, and 26 mm. High-speed tool steel (hereinafter referred to as HSS) base (end mill) E having a four-blade square shape with dimensions of 6 mm × 13 mm, 10 mm × 22 mm, and 20 mm × 45 mm, respectively, and a twist angle of 30 degrees. -1 to E-6 were produced. The dimensions and shapes of the HSS substrates (end mills) E-1 to E-2, E-3 to E-4, and E-5 to E-6 are the same as the carbide substrates (end mills) C-1 to C-3. , C-4 to C-6, and C-7 to C-8.

  Next, the surfaces of these carbide substrates (end mills) C-1 to C-8 and HSS substrates (end mills) E-1 to E-6 were ultrasonically cleaned in acetone and dried, as shown in FIG. From the (Ti, Al, Si) N layer having a single-phase structure with the target composition and target layer thickness shown in Table 8 under the same conditions as in Example 1 above. The total target layer thickness shown in Table 8 is also the lower layer, and the upper layer consisting of the alternating layers of the thin layer A and the thin layer B having the target composition and the single target layer thickness are also shown in Table 8 along the layer thickness direction. As a surface-coated cutting tool of the present invention, the surface-coated carbide end mill (hereinafter referred to as the present invention coated carbide end mill) 1 to 8 and the surface-coated high-speed tool steel end mill (hereinafter referred to as the present invention) Hereinafter, the present invention coated HSS engine Mill and refers) 9-14 were prepared, respectively.

  For the purpose of comparison, the surfaces of the above-mentioned carbide substrates (end mills) C-1 to C-8 and HSS substrates (end mills) E-1 to E-6 were ultrasonically cleaned in acetone and dried. 2 is charged in the arc ion plating apparatus shown in FIG. 2 and has a single-phase structure with the target composition and target layer thickness shown in Table 9 under the same conditions as in Example 1 (Ti, Al). , Si) By depositing a hard coating layer composed of an N layer, conventional surface coated carbide end mills (hereinafter referred to as conventional coated carbide end mills) 1 to 8 as conventional surface coated cutting tools and conventional surface coated high speeds. Tool steel end mills (hereinafter referred to as conventional coated HSS end mills) 9 to 14 were produced.

(A) Next, of the present invention coated carbide end mills 1-8 and conventional coated carbide end mills 1-8,

(A-1) About this invention coated carbide end mills 1-3 and conventional coated carbide end mills 1-3,
Work material-Plane: 100 mm x 250 mm, thickness: 50 mm thick JIS / SKD11 quenching material (hardness: HRC58),
Cutting speed: 45 m / min. ,
Groove depth (cut): 0.2 mm,
Table feed: 100 mm / min,
A dry high-speed grooving test of the alloy tool steel under the conditions (normal cutting speed is 20 m / min.),
(A-2) About this invention coated carbide end mills 4-6 and conventional coated carbide end mills 4-6,

Work material-Plane: 100 mm × 250 mm, thickness: 50 mm of JIS / SUJ2 quenching material (hardness: HRC56),
Cutting speed: 40 m / min. ,
Groove depth (cut): 0.4 mm,
Table feed: 100 mm / min,
A dry high-speed grooving test of the bearing steel under the conditions (normal cutting speed is 20 m / min.)
(A-3) About the coated carbide end mills 7 and 8 of the present invention and the conventional coated carbide end mills 7 and 8,
Work material-Plane: 100 mm x 250 mm, thickness: 50 mm thick JIS / SKD61 quenching material (hardness: HRC55),
Cutting speed: 75 m / min. ,
Groove depth (cut): 0.8 mm,
Table feed: 40 mm / min,
A dry high-speed grooving test of the alloy tool steel under the conditions (normal cutting speed is 40 m / min.),
In any of the above groove cutting tests (a-1) to (a-3), the cutting groove length until the flank wear width of the outer peripheral edge of the cutting edge reaches 0.1 mm, which is a guide for the service life. Was measured.

(B) Next, among the present coated HSS end mills 9 to 14 and the conventional coated HSS end mills 9 to 14,

(B-1) About the present coated HSS end mills 9 and 10 and the conventional coated HSS end mills 9 and 10,

Work material-Plane: 100 mm x 250 mm, thickness: 50 mm JIS SKD61 (hardness: HRC52) plate material,

Cutting speed: 35 m / min. ,
Groove depth (cut): 3.5 mm,
Table feed: 120 mm / min,
A dry high-speed grooving test of the alloy tool steel under the conditions (normal cutting speed is 20 m / min.),
(B-2) About this invention coated HSS end mills 11 and 12 and conventional coated HSS end mills 11 and 12,

Work material-Plane: 100 mm x 250 mm, thickness: 50 mm JIS SKD11 (hardness: HRC56) plate material,

Cutting speed: 35 m / min. ,
Groove depth (cut): 5.0 mm,
Table feed: 100 mm / min,
A dry high-speed grooving test of the alloy tool steel under the conditions (normal cutting speed is 20 m / min.),
(B-3) About this invention coated HSS end mills 13 and 14 and conventional coated HSS end mills 13 and 14,

Work material-Plane: 100 mm x 250 mm, thickness: 50 mm JIS / SUJ2 (hardness: HRC55) plate,

Cutting speed: 35 m / min. ,
Groove depth (cut): 7.0 mm,
Table feed: 50 mm / min,
A dry high-speed grooving test of the bearing steel under the conditions (normal cutting speed is 20 m / min.)
In any of the groove cutting tests of (b-1) to (b-3) above, the cutting groove length until the flank wear width of the outer peripheral edge of the cutting edge reaches 0.1 mm, which is a guide for the service life. Was measured.
The measurement results of the above (a-1) to (a-3) and (b-1) to (b-3) are shown in Tables 8 and 9, respectively.

The diameters produced in Example 2 above were 8 mm (for forming carbide substrates C-1 to C-3), 13 mm (for forming carbide substrates C-4 to C-6), and 26 mm (for carbide substrates C-). 7, for C-8 formation), and from these three types of round bar sintered bodies, the diameter x length of the groove forming portion is 4 mm x 13 mm (by grinding). Carbide substrates D-1 to D-3), 8 mm × 22 mm (Carbide substrates D-4 to D-6), and 16 mm × 45 mm (Carbide substrates D-7 and D-8), and all Carbide substrates (drills) D-1 to D-8 made of a WC-base cemented carbide having a two-blade shape with a twist angle of 30 degrees were produced.

In addition, using the high-speed tool steel (JIS / SKH55) material used in Example 2 above, the diameter and length of the groove forming portion were 4 mm × 25 mm (HSS substrates F-1, F- 2), 8 mm x 45 mm (HSS bases F-3, F-4), and 16 mm x 90 mm (HSS bases F-5, F-6), and each has a two-blade shape with a twist angle of 30 degrees. HSS substrates (drills) F-1 to F-6 made of high-speed tool steel were produced.

  Next, the cutting edges of these carbide substrates (drills) D-1 to D-8 and HSS substrates (drills) F-1 to F-6 are honed, ultrasonically cleaned in acetone, and dried. In the same manner, the arc ion plating apparatus shown in FIG. 1 was charged, and under the same conditions as in Example 1, it had a single phase structure with the target composition and target layer thickness shown in Table 10 (Ti, Al , Si) N layer, and the upper layer composed of the alternating layers of the thin layer A and the thin layer B having the target composition and the single target layer thickness which are also shown in Table 10 along the layer thickness direction. By carrying out vapor deposition with the overall target layer thickness shown, the present invention surface coated carbide drills (hereinafter referred to as the present invention coated carbide drill) 1 to 8 as the present invention surface coated cutting tool and the present invention surface coated HSS. Drill (hereinafter referred to as the present invention HSS drill) Say) 9-14 was prepared, respectively.

  For comparison purposes, the surfaces of the above-mentioned carbide substrates (drills) D-1 to D-8 and HSS substrates (drills) F-1 to F-6 are subjected to honing and ultrasonically cleaned in acetone. In a dry state, the same was put into the arc ion plating apparatus shown in FIG. 2, and under the same conditions as in Example 1, a single phase structure with the target composition and target layer thickness also shown in Table 11 was obtained. By vapor-depositing a hard coating layer comprising a (Ti, Al, Si) N layer, conventional surface-coated carbide drills (hereinafter referred to as conventional coated carbide drills) 1 to 8 as conventional surface-coated cutting tools and Conventional surface-coated HSS drills (hereinafter referred to as conventional coated HSS drills) 9 to 14 were produced.

(C) Next, of the present invention coated carbide drills 1-8 and conventional coated carbide drills 1-8,
(C-1) About this invention coated carbide drills 1-3 and conventional coated carbide drills 1-3,

Work material-plane: 100 mm x 250 mm, thickness: 50 mm JIS / SKD61 (hardness: HRC54) plate material,
Cutting speed: 40 m / min. ,
Feed: 0.08 mm / rev,
Hole depth: 8 mm,
Wet high-speed drilling cutting test of alloy tool steel under the conditions (normal cutting speed is 20 m / min.),
(C-2) About the present coated carbide drills 4-6 and the conventional coated carbide drills 4-6,

Work material-plane: 100 mm × 250 mm, thickness: 50 mm JIS / SUJ2 (hardness: HRC55) plate material,
Cutting speed: 50 m / min. ,
Feed: 0.1 mm / rev,
Hole depth: 16 mm,
Wet high speed drilling test of bearing steel under the conditions (normal cutting speed is 25 m / min.),
(C-3) About the coated carbide drills 7 and 8 of the present invention and the conventional coated carbide drills 7 and 8,

Work material-Plane: 100 mm x 250 mm, thickness: 50 mm JIS SKD11 (hardness: HRC56) plate material,
Cutting speed: 45 m / min. ,
Feed: 0.12 mm / rev,
Hole depth: 32 mm,
Wet high-speed drilling machining test of alloy tool steel under the conditions (normal cutting speed is 25 m / min.),

In any of the wet high-speed drilling tests (using water-soluble cutting oil) of any of the above (c-1) to (c-3), the number of drilling processes until the flank wear width of the tip cutting edge surface reaches 0.3 mm Was measured. The measurement results are shown in Tables 10 and 11, respectively.
(D) Next, among the above-mentioned present invention coated HSS drills 9-14 and conventional coated HSS drills 9-14,
(D-1) For the coated HSS drills 9 and 10 of the present invention and the conventional coated HSS drills 9 and 10,

Work material-Plane: 100 mm × 250 mm, thickness: 50 mm JIS SKD11 (hardness: HRC55) plate,

Cutting speed: 30 m / min. ,
Feed: 0.12 mm / rev,
Hole depth: 12 mm,
Wet high-speed drilling machining test of alloy tool steel under the conditions (normal cutting speed is 15 m / min.),
(D-2) About this invention coated HSS drills 11 and 12 and conventional coated HSS drills 11 and 12,

Work material-plane: 100 mm × 250 mm, thickness: 50 mm JIS / SUJ2 (hardness: HRC55) plate material,

Cutting speed: 30 m / min. ,
Feed: 0.15 mm / rev,
Hole depth: 24 mm,
Wet high-speed drilling test of bearing steel under the conditions (normal cutting speed is 15 m / min.)
(D-3) About this invention coated HSS drills 13 and 14 and conventional coated HSS drills 13 and 14,

Work material-Plane: 100 mm x 250 mm, thickness: 50 mm JIS SKD61 (hardness: HRC52) plate material,

Cutting speed: 40 m / min. ,
Feed: 0.16 mm / rev,
Hole depth: 48 mm,
Wet high-speed drilling cutting test of alloy tool steel under the conditions (normal cutting speed is 20 m / min.),
In any of the wet high-speed drilling tests (using water-soluble cutting oil) in any of the above (d-1) to (d-3), the number of drilling processes until the flank wear width of the tip cutting edge surface reaches 0.3 mm Was measured.
The measurement results of the above (c-1) to (c-3) and (d-1) to (d-3) are shown in Tables 10 and 11, respectively.

  As a result, the present coated carbide tips 1 to 16 as the present surface coated cutting tool, the present coated carbide end mill 1 to 8, the present coated HSS end mill 9 to 14, the present coated carbide drill 1 to 8 and the present invention HSS drills 9 to 14 (Ti, Al, Si) N hard coating layer composed of (Ti, Al, Si) N, upper layer thin layer A and thin layer B, further composition of the lower layer, as a conventional coated tool Conventional coated carbide tips 1 to 16, conventional coated carbide end mills 1 to 8, conventional coated HSS end mills 9 to 14, conventional coated carbide drills 1 to 8 and conventional coated HSS drills 9 to 14 (Ti, Al, Si ) When the composition of the hard coating layer made of N was measured by an energy dispersive X-ray analysis method using a transmission electron microscope, each showed substantially the same composition as the target composition.

Further, when the average layer thickness of the constituent layers of the hard coating layer was subjected to cross-sectional measurement using a transmission electron microscope, all showed the same average value (average value of five locations) as the target layer thickness.

  From the results shown in Tables 3 to 11, the surface-coated cutting tool of the present invention has an upper layer in which the hard coating layer has an alternately laminated structure of thin layers A and B each having an average layer thickness of 5 to 20 nm. (Having an average layer thickness of 0.5 to 1.5 μm) and a lower layer having a single-phase structure (having an average layer thickness of 2 to 6 μm), the upper layer having excellent heat resistance and predetermined In addition, since the lower layer has excellent high-temperature hardness, chipping occurs even in high-speed cutting with high heat generation of hardened steel of alloy tool steel and bearing steel. However, conventional surface-coated cutting tools with a hard coating layer consisting of a single-phase (Ti, Al, Si) N layer, in particular, lack the heat resistance of the hard coating layer, while exhibiting excellent wear resistance. It is clear that the wear progresses rapidly due to the above, and that the service life is reached in a relatively short time.

As described above, the surface-coated cutting tool of the present invention is excellent not only for cutting under normal cutting conditions such as various steels and cast iron, but also for high-speed cutting with high heat generation of high hardness steel. It exhibits excellent wear resistance and excellent cutting performance over a long period of time, so it is fully satisfactory for high-performance cutting equipment, labor saving and energy saving of cutting, and cost reduction. It can be done.

The arc ion plating apparatus used for forming the hard coating layer which comprises the surface coating cutting tool of this invention is shown, (a) is a schematic plan view, (Si) is a schematic front view. It is a schematic explanatory drawing of a normal arc ion plating apparatus.

Claims (1)

On the surface of a cemented carbide substrate made of tungsten carbide-based cemented carbide or titanium carbonitride-based cermet, or on the surface of a high-speed tool steel substrate,
(A) Both are composed of an upper layer and a lower layer made of a composite nitride of Ti, Al, and Si, the upper layer has an average layer thickness of 0.5 to 1.5 μm, and the lower layer has an average layer thickness of 2 to 6 μm. Have
(B) Each of the upper layers has an alternately laminated structure of thin layers A and B each having an average layer thickness of 5 to 20 nm (nanometer),
The thin layer A is
Ti satisfying the composition formula: [Ti _{1− (E + F)} Al _E Si _F ] N (wherein E is 0.15 to 0.30 and F is 0.20 to 0.35 in atomic ratio) A composite nitride layer of Al and Si;
The thin layer B is
_{Formula: [Ti 1- (M + N} ) Al M Si N] N ( provided that an atomic ratio, M is from .50 to 0.65, N denotes the 0.01-0.10) and Ti which satisfies A composite nitride layer of Al and Si,
(C) the lower layer has a single phase structure;
_{Formula: [Ti 1- (X + Y} ) Al X Si Y] N ( provided that an atomic ratio, X is from .50 to 0.65, Y denotes the 0.01-0.10) and Ti which satisfies A composite nitride layer of Al and Si;
A surface-coated cutting tool that exhibits excellent wear resistance in high-speed cutting of high-hardness steel, formed by vapor-depositing a hard coating layer made of

Images