JP2007167983A - Surface coated cemented carbide-made cutting tool having hard coating layer exhibiting excellent wear resistance in high-speed cutting soft material hard to work - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a surface coated cutting tool having a hard coating layer exhibiting excellent wear resistance in high-speed cutting soft material hard to work. <P>SOLUTION: In this surface coated cutting tool, the following hard coating layer is formed on the surface of a cemented carbide base. The hard coating layer includes: (a) a surface layer formed of Cr boride layer; and (b) a wear resisting hard layer formed of a compound nitride layer of Ti, Al and Si, which satisfies a composition formula: (Ti<SB>1-(X+Y)</SB>Al<SB>X</SB>Si<SB>Y</SB>)N (wherein 0.45≤X≤0.65, 0.01≤Y≤0.10, and 0.50≤X+Y≤0.70 by atomic ratio). In the surface layer, the surface roughness of a cutting face at least including a cutting edge ridge part and a flank part is set at 0.2 μm or less Ra by injecting a polishing liquid mixed with aluminum oxide fine grains as an injection abrasive by a wet blast to polish under the coexistence of pulverized Cr nitride fine grains made by wet blasting the abrasive layer and aluminum oxide fine grains as the injection abrasive in the state where the abrasive layer formed of Cr nitride layer is formed on the whole surface of the surface layer by vapor deposition. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  According to the present invention, the hard coating layer is composed of a wear-resistant hard layer having excellent high-temperature hardness, high-temperature strength and heat resistance, and a surface layer having excellent high-temperature oxidation resistance, and thus, particularly, the chip has a high viscosity. Even when the cutting of soft difficult-to-cut materials (work materials) such as stainless steel, high manganese steel, and mild steel, which are easily welded to the tool surface, is performed under high-speed cutting conditions with high heat generation. And the chips are heated to a high temperature, the viscosity and weldability are further increased, and the oxidation reactivity to the surface of the hard coating layer is increased accordingly. A surface-coated cemented carbide cutting tool (hereinafter referred to as coated carbide) that significantly suppresses the progress of wear of the hard coating layer due to the oxidation reaction suppressing effect of the surface layer, and exhibits excellent wear resistance over a long period of time. Craft It relates to) that.

  Generally, for coated carbide tools, a throw-away tip that is attached to the tip of a cutting tool for turning or flattening of various steel and cast iron work materials, 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.

Further, as a coated carbide tool, on the surface of a carbide substrate composed of tungsten carbide (hereinafter referred to as WC) -based cemented carbide or titanium carbonitride (hereinafter referred to as TiCN) -based cermet,
Composition formula: (Ti _{1- (X + Y)} Al _X Si _Y ) N (however, in atomic ratio, 0.45 ≦ X ≦ 0.65, 0.01 ≦ Y ≦ 0.10, 0.50 ≦ X + Y ≦ 0) A hard coating layer composed of a composite nitride of Ti, Al, and Si (hereinafter referred to as (Ti, Al, Si) N) satisfying .70) is physically vapor-deposited with an average layer thickness of 1 to 10 μm. A coated carbide tool is known, and the (Ti, Al, Si) N layer, which is a hard coating layer of the coated carbide tool, has high temperature hardness and heat resistance due to Al as a component, and high temperature due to the Ti. Combined with the effect of improving heat resistance due to the same Si, it also has excellent cutting performance when used for continuous cutting and intermittent cutting of various steels and cast iron. Are known.

Furthermore, the above-mentioned coated carbide tool is, for example, the above-mentioned carbide substrate is inserted into an arc ion plating apparatus which is one type of physical vapor deposition apparatus schematically shown in FIG. For example, an arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which a Ti—Al—Si alloy having a predetermined composition is set, for example, at a current of 90 A, while being heated to a temperature of 500 ° C. At the same time, nitrogen gas is introduced into the apparatus as a reaction gas to form a reaction atmosphere of, for example, 2 Pa. On the other hand, the carbide substrate is applied to the surface of the carbide substrate under a condition that a bias voltage of, for example, −100 V is applied. It is also known that it is produced by vapor-depositing a wear-resistant hard layer made of the (Ti, Al, Si) N layer as a hard coating layer.
Japanese Patent No. 2793773

  The performance and automation of cutting machines in recent years have been remarkable. On the other hand, there are strong demands for labor saving and energy saving and further cost reduction for cutting. Accordingly, cutting speed has been increased and types of work materials have been increased. There is a tendency that a general-purpose coated carbide tool not limited to the above is widely desired, but in the above-mentioned conventional coated carbide tool, this is applied to general steels such as low alloy steel and carbon steel, ductile cast iron, gray cast iron, etc. There is no problem when it is used for machining of ordinary cast iron, but it is particularly difficult to cut stainless steel, high-manganese steel, and soft difficult-to-cut materials such as mild steel that have high chip viscosity and are easily welded to the tool surface ( When the cutting of the workpiece is performed under high-speed cutting conditions with high heat generation, the workpiece and the chips are heated to a high temperature and the viscosity and weldability are further increased. Hard cover Since the oxidation reaction to the layer surface becomes active, the wear progress of the hard coating layer is accelerated, the reach this result relatively short time service life at present.

In view of the above, the present inventors have developed the above-described coated carbide tool exhibiting excellent wear resistance with an excellent wear-resistant hard layer in high-speed cutting of the above-mentioned soft difficult-to-cut materials. As a result of conducting research focusing on conventional coated carbide tools,
(A) For example, an arc ion plating apparatus (hereinafter abbreviated as AIP apparatus) and a sputtering apparatus (hereinafter referred to as SP apparatus) having a structure shown in FIG. 1 (a) in a schematic plan view and in FIG. Is a coexisting vapor deposition apparatus, that is, a carbide substrate mounting rotary table is provided at the center of the apparatus, and a predetermined composition is provided on one side as a cathode electrode (evaporation source) of the AIP apparatus with the rotary table interposed therebetween. Ti-Al-Si alloy, the cathode electrode (vapor source) as Cr borides of the SP device on the other side with (hereinafter, indicated by CrB ₂₎ sintered body of powder (hereinafter, CrB of ₂ sintered body) opposite the Using the deposited vapor deposition apparatus, a plurality of cemented carbide substrates are mounted in a ring shape along the outer peripheral portion at a predetermined distance in the radial direction from the central axis on the rotary table of the apparatus. Basically, the Ti-Al-Si is first rotated while rotating the rotary table in a nitrogen atmosphere and rotating the carbide substrate itself for the purpose of uniforming the thickness of the wear-resistant hard layer formed by vapor deposition. Arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode of the alloy, and the (Ti, Al, Si) N layer is resistant to an average layer thickness of 0.8 to 5 μm on the surface of the carbide substrate. After vapor deposition as a wear hard layer, the atmosphere in the vapor deposition apparatus is substantially changed to an Ar atmosphere instead of a nitrogen atmosphere, and CrB ₂ is disposed as a cathode electrode (evaporation source) of the SP apparatus. When sputtering of the bonded body is started and a CrB ₂ layer is deposited on the (Ti, Al, Si) N layer as a surface layer with an average layer thickness of 0.8 to 5 μm, the resulting coated carbide tool is Especially the viscosity of the chips Even when it is used to perform cutting of soft difficult-to-cut materials (work materials) such as stainless steel, high manganese steel, and mild steel that are easy to weld to the tool surface under high-speed cutting conditions with high heat generation, The wear-resistant hard layer composed of the (Ti, Al, Si) N layer is heated to a high temperature by the surface layer composed of the CrB ₂ layer having excellent high-temperature oxidation resistance, and the viscosity and weldability are further increased. Along with this, it is protected from the work material and chips with increased oxidation reactivity to the hard coating layer, and the progress of wear is remarkably suppressed, so that excellent wear resistance is exhibited over a long period of time. thing.
(B) However, the CrB ₂ layer formed on the (Ti, Al, Si) N layer of (a) has a relatively rough vapor deposition surface, and this causes high-speed cutting of the soft difficult-to-cut material in particular. Then, chipping (small chipping) tends to occur at the cutting edge. Therefore, 15 to 60 mass% aluminum oxide (hereinafter referred to as Al ₂ O ₃ ) fine particles as a proportion of the total amount with water as a wet abrasive, that is, a spray abrasive, is used as a normal polishing means. It is conceivable to apply wet blasting to the surface by spraying the polished polishing liquid, but even with the wet blasting, the measurement based on the compliant standard JIS B0601-1994 (all the following surface roughness is such compliant standard) In this case, it is only possible to ensure a surface roughness of Ra: 0.3 to 0.6 μm. With this surface roughness, high-speed cutting of the soft difficult-to-cut material can be achieved. It should not be possible to satisfactorily suppress chipping at the cutting edge.
(C) On the other hand, as shown in FIG. 1, a cathode electrode (on the entire surface of the rake face and the flank face including the cutting edge ridge line portion of the CrB ₂ layer constituting the surface layer of the hard coating layer in the above-mentioned coated carbide tool, Using an AIP device in which metal Cr is disposed as the evaporation source), the atmosphere in the device is a nitrogen atmosphere, and arc discharge is generated between the cathode electrode (evaporation source) and the anode electrode, and an average of 0.5 to 5 μm With the layer thickness, a Cr nitride (hereinafter referred to as CrN) layer is formed by vapor deposition.
When a polishing liquid containing 15 to 60% by mass of Al ₂ O ₃ fine particles as a spraying abrasive in a ratio to the total amount of water is sprayed by wet blasting as in (b) above, the CrN layer ( (Hereinafter referred to as CrN abrasive layer) is pulverized and pulverized by the Al ₂ O ₃ fine particles, becomes CrN fine particles and acts as an abrasive in the presence of the Al ₂ O ₃ fine particles, and constitutes the surface layer of the hard coating layer The surface of the CrB ₂ layer to be polished is polished. As a result, the surface of the CrB ₂ layer after polishing is smoothed to a surface roughness of Ra: 0.2 μm or less. Using a coated carbide tool in which at least a rake face portion including a cutting edge ridge line portion and a flank portion of a surface of a certain CrB ₂ layer are smoothed to a surface roughness of Ra: 0.2 μm or less, particularly the soft difficult-to-cut material When high-speed cutting is performed Chipping generation at the cutting edge is prevented, and the hard coating layer exhibits excellent wear resistance over a long period of time.
The research results shown in (a) to (c) above were obtained.

This invention was made based on the above research results, and on the surface of the carbide substrate,
(A) As a surface layer, a CrB ₂ layer formed by vapor deposition using an SP apparatus and having an average layer thickness of 0.8 to 5 μm,
(B) The wear-resistant hard layer is formed by vapor deposition using an AIP apparatus, and has an average layer thickness of 0.8 to 5 μm.

Composition formula: (Ti _{1- (X + Y)} Al _X Si _Y ) N (however, in atomic ratio, 0.45 ≦ X ≦ 0.65, 0.01 ≦ Y ≦ 0.10, 0.50 ≦ X + Y ≦ 0) .70),

(Ti, Al, Si) N layer satisfying
A coated carbide tool formed by forming a hard coating layer comprising the above (a) and (b),
Furthermore, the surface roughness of the rake face portion and the flank face portion including at least the cutting edge ridge line portion of the surface layer composed of the CrB ₂ layer of the hard coating layer,
In a state where an abrasive layer composed of a CrN layer having an average layer thickness of 0.5 to 5 μm and formed by vapor deposition using an AIP apparatus is vapor-deposited on the entire surface layer,
In wet blasting, as a spraying abrasive, a polishing liquid containing 15 to 60% by mass of Al ₂ O ₃ fine particles in a proportion of the total amount with water is sprayed,
High-speed cutting of a soft difficult-to-cut material with Ra: 0.2 μm or less by polishing in the presence of pulverized CrN fine particles by wet blasting of the abrasive layer and Al ₂ O ₃ fine particles as a spray abrasive. The hard coating layer is characterized by a coated carbide tool that exhibits excellent wear resistance.

Next, the reason why the hard coating layer and the CrN abrasive layer of the coated carbide tool of the present invention and the Al ₂ O ₃ fine particles of the polishing liquid used in wet blasting are numerically limited as described above will be described.
(A) X value and Y value in the composition formula of the wear resistant hard layer The Al component in the (Ti, Al, Si) N layer constituting the wear resistant hard layer improves the high temperature hardness and heat resistance, while the Ti component Has the effect of improving the high-temperature strength and further improving the heat resistance in the coexistence of Al with the same Si component, but the ratio of the X value indicating the proportion of Al to the total amount of Ti and Si (atom If the ratio is less than 0.45, the ratio of Ti will be relatively large, and it will not be possible to secure the excellent high temperature hardness and heat resistance required for high-speed cutting, resulting in rapid progress of wear. On the other hand, when the X value indicating the proportion of Al exceeds 0.65, the proportion of Ti becomes relatively small, and the high-temperature strength rapidly decreases. Chipping (slight chipping) is likely to occur The X value was determined to be 0.45 to 0.65. Moreover, if the Y value indicating the proportion of Si is a proportion of the total amount of Ti and Al, and less than 0.01, the desired heat resistance improvement effect cannot be obtained, while if the Y value exceeds 0.10, Since the high temperature strength is lowered, the Y value is set to 0.01 to 0.10. Furthermore, if the (X + Y) value indicating the total content of Al and Si is less than 0.50, the high-temperature hardness and heat resistance required for high-speed cutting of a soft difficult-to-cut material cannot be sufficiently satisfied. If the (X + Y) value exceeds 0.70, the high-temperature strength required for high-speed cutting of a soft difficult-to-cut material cannot be ensured, so the (X + Y) value is 0.50 or more and 0.70. It was determined as follows.
(B) Average layer thickness of wear-resistant hard layer If the average layer thickness is less than 0.8 μm, it is insufficient to exhibit its excellent wear resistance over a long period, while the average layer thickness is If it exceeds 5 μm, chipping is likely to occur at the cutting edge portion in the high-speed cutting of the hard difficult-to-cut material, so the average layer thickness is set to 0.8 to 5 μm.
(C) Average layer thickness of the surface layer As described above, the hard coating layer has excellent high temperature hardness, high temperature strength and heat resistance of the wear resistant hard layer, and excellent high temperature oxidation resistance of the CrB ₂ layer as the surface layer. Coexistence with the high-temperature heat-extracting soft difficult-to-cut material with excellent heat resistance, the CrB ₂ layer has an average layer thickness of less than 0.8 μm. , It is insufficient to protect the wear-resistant hard layer from the high oxidation reactivity of the soft difficult-to-cut material at the time of cutting to the end of its service life. On the other hand, if the average layer thickness exceeds 5 μm, chipping is applied to the cutting edge. Therefore, the average layer thickness is set to 0.8 to 5 μm.
(D) CrN abrasive layer As described above, CrN abrasive layer during wet blasting, the Al ₂ O ₃ fine formulated as injection abrasive in the polishing liquid milled micronized, the Al ₂ O ₃ becomes CrN fine Acts as an abrasive in the presence of fine particles, and polishes the surface of the CrB ₂ layer constituting the surface layer of the hard coating layer. In this case, if the average layer thickness is less than 0.5 μm, grinding during wet blasting When the average layer thickness exceeds 5 μm, the proportion of Al ₂ O ₃ fine particles blended in the polishing liquid as a jetting abrasive is not sufficient. The balance is lost and the amount is relatively excessive. In this case as well, the polishing function suddenly decreases. In either case, the surface of the CrB ₂ layer is polished to a surface roughness of Ra: 0.2 μm or less. Can Because it Kunar, defining the average layer thickness and 0.5 to 5 [mu] m.
(E) the Al ₂ O ₃ fine fraction polishing liquid Al ₂ O ₃ fine polishing liquid, while coexisting with pulverized CrN fine of CrN abrasive layer during wet blasting, polishing the surface of CrB ₂ layers Even if the ratio is less than 15% by mass or more than 60% by mass with respect to the total amount with water, the polishing function will be abruptly reduced. The mass% was determined.

The coated carbide tool of the present invention has a (Ti, Al, Si) N wear-resistant hard layer having excellent high-temperature hardness, high-temperature strength and heat resistance, excellent high-temperature oxidation resistance, and high-speed cutting. Soft hard-to-cut material (work material) and hard coating layer composed of _two surface layers of CrB that protects the wear-resistant hard layer from the high oxidation reaction of chips. Even if the cutting of the material is performed at a high speed with high heat generation, the surface layer is polished to a surface roughness of Ra: 0.2 μm or less so that chipping at the cutting edge portion is prevented. In combination with this, excellent wear resistance is exhibited over a long period of time.

  Next, the coated carbide 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 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, 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 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 The green compact was sintered in a nitrogen atmosphere of 2 kPa at a temperature of 1500 ° C. for 1 hour. After sintering, the cutting edge portion was subjected to a honing process of R: 0.03 to meet ISO standards / TiCN-based cemented carbide substrates B-1 to B-6 having a chip shape of CNMG120408 were formed.

Further, as a cathode electrode (evaporation source) of the SP device for surface layer formation, CrB ₂ powder having an average particle diameter of 0.8 μm is hot pressed under the conditions of temperature: 1500 ° C., pressure: 20 MPa, holding time: 3 hours. Thus, a CrB ₂ sintered body was produced.
(A) Next, each of the above-mentioned carbide substrates A-1 to A-10 and B-1 to B-6 was ultrasonically cleaned in acetone and dried, and then in the vapor deposition apparatus 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, and corresponded to the target composition shown in Table 4 as the cathode electrode (evaporation source) of the AIP device on one side. A Ti—Al—Si alloy for forming a wear-resistant hard layer having a component composition, a CrB ₂ sintered body for forming a surface layer as a cathode electrode (evaporation source) of the SP device on the other side, and the Ti—Al— Attaching metal Cr for forming a CrN abrasive layer as a cathode electrode (evaporation source) of the AIP device along the rotary table at a position shifted by 90 degrees from each of the Si alloy and the CrB ₂ sintered body,
(B) First, the inside of the apparatus is evacuated and kept at a vacuum of 0.1 Pa or less, and the inside of the apparatus is heated to 500 ° C. with a heater, and then the carbide substrate that rotates while rotating on the rotary table is set to −1000 V. And a current of 100 A is passed between the Ti—Al—Si alloy of the cathode electrode and the anode electrode to generate an arc discharge, whereby the surface of the carbide substrate is made to the Ti—Al—Si. Bombard washed by alloy and
(C) Nitrogen gas is introduced as a reaction gas into the apparatus to form a reaction atmosphere of 3 Pa, a DC bias voltage of −100 V is applied to a carbide substrate rotating while rotating on the rotary table, and a cathode electrode A current of 100 A was passed between the Ti-Al-Si alloy and the anode electrode to generate an arc discharge, so that the surface of the cemented carbide substrate had a target composition and target layer thickness (Ti , Al, Si) N layer is deposited as a wear-resistant hard layer of the hard coating layer,
(D) Next, the purpose of improving the adhesion between the (Ti, Al, Si) N layer as the wear-resistant hard layer already formed by vapor deposition and the CrB ₂ layer as the surface layer to be vapor-deposited from now on Then, while continuing the arc discharge between the cathode electrode and the anode electrode of the wear-resistant hard layer forming Ti—Al—Si alloy, a mixed gas of Ar and nitrogen (N ₂ : Ar = 3: 1 by volume ratio is introduced, and the atmosphere in the apparatus is set to 3 Pa. At the same time, spatter is generated at a power of 3 kW on the CrB ₂ sintered body arranged as the cathode electrode (evaporation source) of the SP apparatus. This state was maintained for 20 minutes, and Ti, Al, Si, and Cr composite boronitride layers as adhesion bonding layers (in this case, the average layer thickness was 0.3 μm in all subsequent measurements. Average of 0.1-0.5 μm Excellent adhesion bonding properties at a thickness to form a to) secured,
(E) Subsequently, the sputtering between the CrB ₂ sintered body arranged as the cathode electrode (evaporation source) of the SP apparatus and the anode electrode is continued in the same condition (sputtering output: 3 kW) and introduced into the apparatus. The gas to be used is changed from a mixed gas of Ar and nitrogen to Ar gas, and the atmosphere in the apparatus is set to 0.5 Pa. At the same time, an arc between the cathode electrode and the anode electrode of the wear-resistant hard layer forming Ti-Al-Si alloy. Discharging is stopped, sputtering is performed for a time corresponding to the layer thickness under these conditions, and a CrB ₂ layer having a target layer thickness similarly shown in Table 4 is deposited as a surface layer of the hard coating layer,
(F) Further, nitrogen gas is introduced into the apparatus instead of Ar gas, and the atmosphere in the apparatus is changed to a nitrogen atmosphere of 3 Pa. At the same time, the sputtering is stopped, and the rotation is performed while rotating on the rotary table. A DC bias voltage of −100 V is applied to the hard substrate, and a current of 100 A is passed between the metal Cr, which is the cathode electrode of the AIP device, and the anode electrode to generate an arc discharge, whereby the CrB ₂ layer (surface A CrN abrasive layer having a target layer thickness also shown in Table 4 is formed on the entire surface of the layer) by vapor deposition,
(G) Subsequently, the coated carbide tool for forming the CrN abrasive layer was subjected to wet blasting under the blasting conditions shown in Table 3 and in the combinations shown in Table 4, and was composed of _two CrB layers. By grinding the rake face portion and the flank face portion including at least the cutting edge ridge line portion of the surface layer to the surface roughness shown in Table 4, the surface coated carbide throwaway of the present invention as the coated carbide tool of the present invention. Chips (hereinafter referred to as the present invention-coated chips) 1 to 16 were produced.

Further, for the purpose of confirming the action and effect of the CrB ₂ layer which is the surface layer of the above-described coated chip of the present invention, as shown in Table 5, the CrB ₂ layer is not formed and the wear-resistant hard layer is used. Comparative coated carbide tool under the same conditions except that the target layer thickness of the (Ti, Al, Si) N layer is the sum of the target layer thickness of the wear-resistant hard layer and the target layer thickness of the surface layer of the coated chip of the present invention. Comparative surface-coated cemented carbide throwaway tips (hereinafter referred to as comparative coated tips) 1 to 16 were produced.

  Table 5 shows the surface roughness after wet blasting of the (Ti, Al, Si) N layers constituting the wear-resistant hard layers of the comparative coated chips 1 to 16 obtained as a result.

Next, in the state where each of the above various coated chips is screwed to the tip of the tool steel tool with a fixing jig, the present coated chips 1-16 and the comparative coated chips 1-16,
Work material: JIS / SUS304 round bar,
Cutting speed: 230 m / min. ,
Cutting depth: 2.5 mm,
Feed: 0.25 mm / rev. ,
Cutting time: 5 minutes,
A dry continuous high-speed cutting test of stainless steel under the conditions (referred to as cutting condition A) (normal cutting speed is 150 m / min.),
Work material: JIS / SCMnH2 lengthwise equidistant round bars with 4 vertical grooves,
Cutting speed: 220 m / min. ,
Cutting depth: 3 mm,
Feed: 0.2 mm / rev. ,
Cutting time: 8 minutes,
Of high manganese steel under the above conditions (referred to as cutting condition B) (continuous cutting speed is 150 m / min.),
Work material: JIS / SS400 lengthwise equidistant 4 round bars with flutes,
Cutting speed: 240 m / min. ,
Incision: 2 mm,
Feed: 0.15 mm / rev. ,
Cutting time: 10 minutes,
A dry interrupted high-speed cutting test (normal cutting speed is 180 m / min.) Of mild steel under the above conditions (referred to as cutting condition C), and the flank wear width of the cutting edge was measured in any of the cutting tests. The measurement results are shown in Table 6.

As raw material powders, medium coarse WC powder having an average particle diameter of 5.5 μm, fine WC powder of 0.8 μm, TaC powder of 1.3 μm, NbC powder of 1.2 μm, ZrC of 1.2 μm 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, and 1 Prepare 8 .mu.m Co powder, mix these raw material powders with the composition shown in Table 7, add wax, ball mill in acetone for 24 hours, dry under reduced pressure, and then press at a pressure of 100 MPa. The green compacts were press-molded, and these green compacts were heated to a predetermined temperature in the range of 1370 to 1470 ° C. at a rate of temperature increase of 7 ° C./min in a 6 Pa vacuum atmosphere. After holding at temperature for 1 hour, sintering under furnace cooling conditions 3 types of sintered carbide rod-forming bodies for forming a carbide substrate having diameters of 8 mm, 13 mm, and 26 mm were formed, and further, the three types of sintered rods for round bar were subjected to grinding, as shown in Table 7. Made of WC-base cemented carbide with a combination of 4 blade square shape with diameter and length of 6mm × 13mm, 10mm × 22mm, and 20mm × 45mm respectively, and a twist angle of 30 degrees. Carbide substrates (end mills) C-1 to C-8 were produced.

Subsequently, the surfaces of these carbide substrates (end mills) C-1 to C-8 were ultrasonically cleaned in acetone and dried, and then charged into the vapor deposition apparatus shown in FIG. And a wear-resistant hard layer comprising a (Ti, Al, Si) N layer having the target composition and target layer thickness shown in Table 8 and a CrB ₂ layer having the target layer thickness also shown in Table 8. A hard coating layer composed of a surface layer is formed by vapor deposition, and wet blasting is performed under the blasting conditions shown in Table 3 and in the combinations shown in Table 8, so that at least a surface layer composed of CrB ₂ layers is cut. By grinding the rake face portion and the flank face portion including the edge line to the surface roughness shown in Table 8, the surface coated carbide end mill of the present invention as the coated carbide tool of the present invention (hereinafter referred to as the present coated material). Called end mill) 8 were prepared, respectively.

Further, for the purpose of confirming the action and effect of the CrB ₂ layer which is the surface layer of the above-mentioned coated end mill of the present invention, as shown in Table 8, the CrB ₂ layer is not formed and the wear resistant hard layer is used. Comparative coated carbide tool under the same conditions except that the target layer thickness of the (Ti, Al, Si) N layer is the sum of the target layer thickness of the wear resistant hard layer and the target layer thickness of the surface layer of the coated end mill of the present invention. Comparative surface-coated cemented carbide end mills (hereinafter referred to as comparative coated end mills) 1 to 8 were produced.

  Table 8 shows the surface roughness after wet blasting of the (Ti, Al, Si) N layer constituting the wear resistant hard layers of the comparative coated end mills 1 to 8 obtained as a result.

Next, of the present invention coated end mills 1-8 and comparative coated end mills 1-8, the present invention coated end mills 1-3 and comparative coated end mills 1-3 are as follows:
Work material-plane: 100 mm × 250 mm, thickness: 50 mm JIS / SS400 plate material,
Cutting speed: 50 m / min. ,
Groove depth (cut): 3 mm,
Table feed: 300 mm / min,
Dry high-speed grooving test of mild steel under normal conditions (normal cutting speed is 30 m / min.),
About this invention coated end mills 4-6 and comparative coated end mills 4-6,
Work material-plane: 100 mm × 250 mm, thickness: 50 mm JIS / SCMnH2 plate material,
Cutting speed: 60 m / min. ,
Groove depth (cut): 4.5 mm,
Table feed: 350 mm / min,
Dry high-speed grooving test of high manganese steel under the conditions of (normal cutting speed is 40 m / min.),
For the coated end mills 7 and 8 and the comparative coated end mills 7 and 8 of the present invention,
Work material-Plane: 100 mm × 250 mm, thickness: 50 mm JIS / SUS316 plate material,
Cutting speed: 65 m / min. ,
Groove depth (cut): 8 mm,
Table feed: 200 mm / min,
Stainless steel dry high-speed grooving test under normal conditions (normal cutting speed is 35 m / min.)
In each of the groove cutting tests, the cutting groove length was measured until the flank wear width of the outer peripheral edge of the cutting edge reached 0.15 mm, which is a guide for the service life. The measurement results are shown in Table 8, 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.

Next, the cutting edges of these carbide substrates (drills) D-1 to D-8 are subjected to honing, ultrasonically cleaned in acetone, and dried, and then loaded into the vapor deposition apparatus shown in FIG. Then, under the same conditions as in Example 1, the wear-resistant hard layer composed of the (Ti, Al, Si) N layer having the target composition and target layer thickness shown in Table 9, and the target layer thickness also shown in Table 9 A hard coating layer composed of a surface layer composed of _two layers of CrB is vapor-deposited and further subjected to wet blasting under the blasting conditions shown in Table 3 and the combinations shown in Table 9 to form a CrB _two layer. The surface coated carbide drill of the present invention as the coated carbide tool of the present invention is obtained by polishing the rake face portion and the flank face portion including at least the cutting edge ridge line portion of the surface layer to the surface roughness similarly shown in Table 9. (Hereinafter, the present invention coated drill Refers) 1-8 were prepared, respectively.

Further, for the purpose of confirming the effect of the CrB ₂ layer, which is the surface layer of the above-described coated drill according to the present invention, as shown in Table 9, the CrB ₂ layer is not formed and the wear resistant hard layer is used. A comparative coated carbide tool under the same conditions except that the target layer thickness of the (Ti, Al, Si) N layer is the sum of the target layer thickness of the wear-resistant hard layer and the surface layer of the coated drill of the present invention. Comparative surface coated carbide drills (hereinafter referred to as comparative coated drills) 1 to 8 were manufactured.

  Table 9 shows the surface roughness after wet blasting of the (Ti, Al, Si) N layers constituting the wear-resistant hard layers of the comparative coated drills 1 to 8 obtained as a result.

Next, of the present invention coated drills 1-8 and comparative coated drills 1-8, for the present invention coated drills 1-3 and comparative coated drills 1-3,

Work material-plane: 100 mm × 250 mm, thickness: 50 mm JIS / SCMnH2 plate material,

Cutting speed: 50 m / min. ,
Feed: 0.2 mm / rev,
Hole depth: 12 mm,

Wet high speed drilling test of high manganese steel under normal conditions (normal cutting speed is 25 m / min.),
About this invention coated drill 4-6 and comparative coated drill 4-6,

Work material-Plane: 100 mm × 250 mm, thickness: 50 mm JIS / SUS316 plate material,
Cutting speed: 60 m / min. ,
Feed: 0.25 mm / rev,
Hole depth: 24 mm,
Wet high-speed drilling test of stainless steel under normal conditions (normal cutting speed is 30 m / min.),
About this invention covering drills 7 and 8 and comparative covering drills 7 and 8,
Work material-plane: 100 mm × 250 mm, thickness: 50 mm JIS / SS400 plate material,
Cutting speed: 65 m / min. ,
Feed: 0.15 mm / rev,
Hole depth: 50 mm,
Wet high-speed drilling test of mild steel under the conditions of (normal cutting speed is 35 m / min.),
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 0.25 mm was measured. The measurement results are shown in Table 9, respectively.

  Wear-resistant hard layers and surfaces constituting the hard coating layers of the present coated chips 1-16, the present coated end mills 1-8, and the present coated drills 1-8 as the present coated carbide tools obtained as a result. The composition of the layers and the composition of the wear resistant hard layers of comparative coated tips 1 to 16, comparative coated end mills 1 to 8 and comparative coated drills 1 to 8 as a comparative coated carbide tool were measured using a transmission electron microscope. When measured by energy dispersive X-ray analysis, each showed substantially the same composition as the target composition.

  Further, when the average layer thickness of the surface layer of the hard coating layer and the wear-resistant hard layer was measured with a scanning electron microscope, the average value was substantially the same as the target layer thickness (average value of five locations). )showed that.

From the results shown in Tables 4 to 9, the hard coating layer has high-temperature hardness, high-temperature strength and heat-resistant (Ti, Al, Si) N-layer wear-resistant hard layer and excellent high-temperature oxidation resistance. The coated carbide tool of the present invention composed of _two surface layers of CrB that protects the wear-resistant hard layer from the high-temperature oxidation reaction atmosphere at the time of cutting are various stainless steels, high-manganese steels, mild steels, etc. In spite of high heat generation in high-speed cutting of soft difficult-to-cut materials, it has excellent wear resistance, whereas it consists only of (Ti, Al, Si) N wear-resistant hard layers In the comparative coated carbide tool, it is clear that the wear progress of the cutting edge portion is fast and the service life is reached in a relatively short time by high-speed cutting with high heat generation of the soft difficult-to-cut material.

  As described above, the coated carbide tool of the present invention is not only for cutting under normal cutting conditions such as various types of steel and cast iron, but also for high-speed cutting of the above-mentioned soft difficult-to-cut materials with high heat generation. However, because it exhibits excellent wear resistance and excellent cutting performance over a long period of time, it is possible to improve the performance and automation of cutting equipment, reduce labor and energy of cutting, and reduce costs. It can respond satisfactorily.

The vapor deposition apparatus used for forming the surface coating layer which comprises a coated carbide tool is shown, (a) is a schematic plan view, (b) 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 cermet,
(A) Cr boride layer formed as a surface layer by vapor deposition using a sputtering apparatus and having an average layer thickness of 0.8 to 5 μm;
(B) The wear-resistant hard layer is formed by vapor deposition using an arc ion plating apparatus, and has an average layer thickness of 0.8 to 5 μm.
Composition formula: (Ti _{1- (X + Y)} Al _X Si _Y ) N (however, in atomic ratio, 0.45 ≦ X ≦ 0.65, 0.01 ≦ Y ≦ 0.10, 0.50 ≦ X + Y ≦ 0) .70),
Ti, Al and Si composite nitride layer satisfying
In the surface-coated cemented carbide cutting tool formed by forming a hard coating layer comprising the above (a) and (b),
Further, the surface roughness of the rake face portion and the flank face portion including at least the cutting edge ridge line portion of the surface layer composed of the Cr boride layer of the hard coating layer,
In the state where the entire surface layer is vapor-deposited using an arc ion plating apparatus and an abrasive layer composed of a Cr nitride layer having an average layer thickness of 0.5 to 5 μm is vapor-deposited,
In wet blasting, as a spraying abrasive, a polishing liquid containing 15 to 60% by mass of aluminum oxide fine particles in a proportion of the total amount with water is sprayed,
In the measurement based on the conformity standard JIS B0601-1994, it was polished in the presence of pulverized Cr nitride fine particles by wet blasting of the abrasive layer and aluminum oxide fine particles as a spray abrasive, and Ra: 0.00. 2 μm or less,
A surface-coated cemented carbide cutting tool that exhibits excellent wear resistance due to its high-speed cutting of soft, difficult-to-cut materials.

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