JP2002137120A - Surface covered high speed tool steel gear cutting tool having hard covered layer having excellent chip lubrication property - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface covered high speed tool steel gear cutting tool having a hard covered layer having excellent chip lubrication property. SOLUTION: A first thin layer of the surface covered high speed tool steel gear cutting tool which is formed by alternately laminating the first thin layer and a second thin layer having individual average layer thickness of 0.005 to 0.2 μm and has a hard covered layer having average layer thickness of 2 to 15 μm on the whose by physically depositing it on a surface of a high speed tool steel basic body is composed of either or both of a compound nitride of Ti and Al satisfying atomic ratio of X: 0.30 to 0.70 and m: 0.6 to 0.99 and compound carbon-nitride of Ti and Al according to the measurement by an Auger spectral analyzer in a central part in the direction of thickness when expressed by a composition formula: [Ti1-XAlX]N and [Ti1-XAlX]C1-mNm, and the second thin layer is composed of either or both of a compound nitride of Ti, Al, and Ta satisfying atomic ratio of X: 0.30 to 0.70, Y: 0.01 to 0.35, and m: 0.6 to 0.99 and compound carbon-nitride of Ti, Al, and Ta according to the measurement by the Auger spectral analyzer in the central part in the direction of thickness when expressed by a composition formula: [Ti1-(X+Y)AlXTaY]N and [Ti1-(X+Y)AlXTaY]C1-mNm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a low-alloy steel, in which a hard coating layer exhibits excellent lubricating properties against chips, and therefore has a particularly high viscosity and the chips are easily welded to the cutting surface. Even when used for high-speed gear cutting of gears made of difficult-to-cut materials such as mild steel, the surface coating height ensures excellent cutting performance over a long period without chipping or chipping (small chipping) of the cutting edge. The present invention relates to a speed cutting tool made of speed tool steel (hereinafter, referred to as a coated tooth cutting tool).

[0002]

2. Description of the Related Art Conventionally, various gears are generally used as structural members of automobiles, aircrafts, and various types of driving devices. Cutting tools are used. As the above-mentioned gear cutting tool, for example, as described in JP-A-7-310173, a composition formula: [Ti _1-X Al _X ] N and [Ti _{1 -X} Al _X ] C _1-m N _m , when measured by an Auger spectrometer at the center in the thickness direction, X: 0.30 to 0.70, m: 0.6 to 0.99
Complex nitride of Ti and Al satisfying the following [hereinafter, (Ti, A
l) a layer represented by N] or a composite carbonitride of Ti and Al [hereinafter represented by (Ti, Al) CN] layer;
A coated tooth cutting tool formed by physical vapor deposition of a hard coating layer composed of both with an average layer thickness of 2 to 15 μm is widely known.

Further, the above-mentioned conventional coated tooth cutting tool uses an arc ion plating apparatus, which is a kind of a physical vapor deposition apparatus schematically shown in FIG. 1, for example, and the inside of the apparatus is heated with a heater, for example, at a pressure of 20 mtorr. As the vacuum of
When heated to a temperature of 500 ° C., for example, a voltage of 35 V and a current of 9 are applied between an anode electrode and a cathode electrode (evaporation source) on which a Ti—Al alloy having a predetermined composition is set.
An arc discharge is generated under the condition of 0 A, and at the same time, a nitrogen gas or a nitrogen gas and a methane gas are introduced into the apparatus as a reaction gas. On the other hand, a base made of high-speed tool steel (hereinafter simply referred to as a base) has, for example,- It is also known that the hard coating layer is manufactured by physical vapor deposition on the surface of the base under a condition that a bias voltage of 200 V is applied.

[0004]

In recent years, the use of FAs in gear processing devices has been remarkable, but on the other hand, there has been a strong demand for labor saving and energy saving and further cost reduction for gear cutting. A versatility that can cut as many materials as possible with one type of gear cutting tool is required,
Although the speed of gear cutting also tends to increase, there is no problem with the above-mentioned conventional coated gear cutting tool when gear cutting is performed under normal conditions such as carbon steel or cast iron. When is used for high-speed gear cutting of gears such as low-alloy steel and mild steel having extremely high viscosity, the chips of these gears are hardened by the (Ti, Al) N layer or the (Ti, Al) layer constituting the hard coating layer. ) CN
Due to the high affinity for the layer, it is easy to weld to the cutting edge surface of the gear cutting tool, and this welding phenomenon becomes more noticeable as the cutting speed increases, and this welding phenomenon causes the cutting edge At present, chipping and chipping occur, resulting in a relatively short service life.

[0005]

Means for Solving the Problems Accordingly, the present inventors have
In view of the above, research was conducted to develop a coated tooth cutting tool that is less likely to cause cutting powder to adhere to the cutting edge surface, especially when used for high-speed gear cutting of gears such as low alloy steel and mild steel. result,
(A) The (Ti, Al) N layer and the (Ti, Al) CN layer constituting the hard coating layer of the above-mentioned conventional coated tooth cutting tool have T
The ratio of i to Al in the total amount, and the center in the thickness direction was measured with an Auger spectrometer, and the atomic ratio was 0.0
When Ta is contained in a solid solution in a ratio of 1 to 0.35, the resulting composite nitride of Ti, Al, and Ta [hereinafter, (Ti, A
l, Ta) N] layer and a composite carbonitride of Ti, Al, and Ta [hereinafter, referred to as (Ti, Al, Ta) CN] layer, the hard coating layer is made of Ta. Has a markedly low affinity for work materials, especially high-viscosity difficult-to-cut materials such as low-alloy steel and mild steel, and has high chip lubricating properties. Is significantly suppressed, but (Ti, A)
1) The excellent toughness of the N layer and the (Ti, Al) CN layer is impaired.

(B) On the other hand, the (Ti, Al) N layer and (T) which are constituent layers of the hard coating layer of the conventional coated tooth cutting tool described above.
(i, Al) CN layer and (Ti, Al, Ta) of the above (a)
The N layer and the (Ti, Al, Ta) CN layer are in a state where the individual layers are extremely thin, that is, 0.005 to 0.2.
When the hard coating layer is formed by alternately laminating both layers in a state where the average layer thickness is set to μm, the hard coating layer has a problem that each layer has due to the thinned alternate lamination structure of the two layers, namely, ( Ti, Al) N layer and (Ti,
Al) CN layer (hereinafter, referred to as first thin layer) has high affinity for chips, and (Ti, Al, Ta) N layer and (Ti, Al, Ta) CN layer (hereinafter, referred to as second thin layer)
Of the first thin layer and the excellent chip lubrication of the second thin layer, the resulting coated gear cuttings Even if this tool is used for high-speed gear cutting of gears made of highly viscous and difficult-to-cut materials such as low alloy steel and mild steel, the cutting edge will not be chipped or chipped. To be able to demonstrate performance. The research results shown in (a) and (b) above were obtained.

[0007] The present invention has been made based on the above-mentioned research results, and has the following effects.
A hard coating layer physically deposited with a total average layer thickness of 15 μm,
Each of the first and second thin layers has an average layer thickness of 0.005 to 0.2 μm and is alternately laminated. The first thin layer is composed of [Ti _1-x Al _x ] N and [Ti _1-X Al _X ] C _1-
When expressed in _m N _m, as measured by Auger spectroscopy apparatus in the thickness direction central portion, in terms of atomic ratio, X: .30-.7
0, m: (Ti, Al) N satisfying 0.6 to 0.99
Layer and / or the (Ti, Al) CN layer, and the second thin layer has a composition formula: [Ti
_{1- (X + Y)} Al _X Ta _Y ] N and [Ti _{1- (X + Y)} Al _X T
a _Y ] C _1-m N _m , when measured by an Auger spectrometer at the center in the thickness direction, X: 0.3 in atomic ratio
0 to 0.70, Y: 0.01 to 0.35, m: 0.6 to
The hard coating layer composed of one or both of the (Ti, Al, Ta) N layer and the (Ti, Al, Ta) CN layer satisfying 0.99 has excellent chip lubrication. The present invention is characterized in that the coated tooth cutting tool has a feature.

[0008] In the coated tooth cutting tool of the present invention,
The average thickness of each of the first thin layer and the second thin layer constituting the alternate lamination of the hard coating layers is 0.005 to 0.2 μm, respectively.
The reason is that, when the average thickness of any of the thin layers is less than 0.005 μm, the properties of each thin layer, that is, the excellent toughness by the first thin layer and the excellent cut by the second thin layer. When the hard coating layer cannot be sufficiently satisfactorily provided with the powder lubricity, on the other hand, when the average layer thickness exceeds 0.2 μm, problems with each thin layer,
That is, the reason is that the chip welding property by the first thin layer and the decrease in toughness by the second thin layer appear in the hard coating layer, and preferably 0.007 to 0.10.
It is good to be set to μm.

Further, in the coated tooth cutting tool of the present invention,
(Ti, Al) N layer and (Ti, Al) CN layer forming the first thin layer of the hard coating layer, and (Ti, Al, Ta) N layer and (Ti, Al) forming the second thin layer , T
a) Al in the CN layer increases the hardness with respect to TiCN and thus forms a solid solution in order to improve the wear resistance. Therefore, the composition formulas: (Ti _1-x Al _x ) N and (Ti _{1 -X} Al _x ) C _1-m N _m and the composition formula: [Ti
_{1- (X + Y)} Al _X Ta _Y ] N and [Ti _{1- (X + Y)} Al _X T
_{a Y] C 1-m N} X values atomic ratio _m (hereinafter the same), 0.3
If the value is less than 0.7, the desired wear resistance cannot be ensured. On the other hand, if the value exceeds 0.7, the X value is set to 0.3 to 0.7 for the reason that chipping or chipping is likely to occur in the cutting edge.
It was decided. Desirably, the X value is set to 0.35 to 0.65.

The C component in the (Ti, Al) CN layer and the (Ti, Al, Ta) CN layer has an effect of improving the hardness, so that the (Ti, Al) CN layer and the (Ti, Al) CN layer , Al, Ta) CN layer is the above (Ti, Al)
The N layer and the (Ti, Al, Ta) N layer each have a relatively high hardness, but in this case, the proportion of the C component in the above composition formula is less than 0.01, that is, the m value is 0.
If it exceeds 99, the predetermined hardness improving effect cannot be obtained, while C
When the ratio of the components exceeds 0.4, that is, when the m value is less than 0.6, the toughness rapidly decreases,
The m value was determined to be 0.6 to 0.99. Desirably, the m value is set to 0.8 to 0.9.

Further, the above-mentioned second thin layer is formed (T
i, Al, Ta) N layer and (Ti, Al, Ta) CN
The layers are the (Ti, Al) N layer of the first thin layer and the (T
As compared with the (i, Al) CN layer, Ta has an excellent chip lubricating property due to the action of Ta.
When the value is less than 1, the solid solution content of Ta is insufficient, and the predetermined chip lubricating property improving effect cannot be provided to the hard coating layer. On the other hand, when the Y value exceeds 0.35, the toughness rapidly decreases, Since this decrease in toughness appears remarkably in the entire hard coating layer, the Y value is set to 0.01 to 0.35. Desirably, the Y value is set to 0.07 to 0.30.

The hard coating layer has a total average layer thickness of 2 to 1
The reason why the thickness is set to 5 μm is that if the layer thickness is 2 μm, the desired excellent wear resistance cannot be secured, while the layer thickness is 1 μm.
If the thickness exceeds 5 μm, chipping and chipping of the cutting edge are liable to occur.
The thickness is preferably set to 0 μm.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated tooth cutting tool of the present invention will be specifically described with reference to examples. As a high-speed tool steel substrate, the material consists of JIS / SKH55, JIS / B
A single hob for gears having the dimensions (module: 2) with the outer shape defined by 4354: 60 mm x total length: 60 mm, and the same material made of JIS / SKH55, JIS / B4
Number of teeth specified in 356: 50, Pitch circle diameter: 100mm
(Module: 2) pinion cutters were prepared, and these high-speed tool steel substrates were ultrasonically cleaned in acetone and dried, and then each of them was applied to a normal arc ion plating apparatus illustrated in FIG. First, a Ti-Al alloy for forming a first thin layer and a Ti-Al-Ta for forming a second thin layer having various component compositions as a cathode electrode (evaporation source).
From among the alloys, an alloy having a predetermined component composition is selected in a predetermined combination, and the selected alloy is mounted on a rotating disk at a position opposite to each other with the rotation axis as a center. While maintaining the vacuum, the inside of the apparatus was heated to 500 ° C. by a heater, and then an Ar gas was introduced into the apparatus to form an Ar atmosphere of 10 Pa. The substrate rotates intermittently with the passage of time, while applying a bias voltage of -800 V to the substrate to clean the substrate surface with Ar gas bombardment. Then, nitrogen gas or nitrogen gas and methane gas are introduced into the apparatus as a reaction gas. 6 Pa and a bias voltage applied to the substrate was lowered to -200 V, and an anode was placed between the cathode electrode (one alloy on the rotating disk) and the anode electrode. And a first thin layer and a second thin layer having the target composition and the target layer thickness shown in Table 1 in the combination shown in Table 2 and also shown in Table 2 on the surface of the substrate. The coated tooth cutting tools 1 to 13 of the present invention were manufactured by depositing hard coating layers having the number of layers alternately laminated.

For the purpose of comparison, a predetermined one of Ti-Al alloys having various component compositions is mounted as a cathode electrode (evaporation source) in the above-mentioned arc ion plating apparatus. Except for the (Ti, Al) N layer and / or (Ti, A) having a target composition and a target layer thickness as shown in Table 3,
1) Conventional coated tooth cutting tools 1 to 12 were manufactured by depositing a hard coating layer composed of a CN layer.

The respective hard coating layers constituting the coated tooth cutting tools 1 to 13 of the present invention and the conventional coated tooth cutting tools 1 to 12 obtained as described above are formed at the central portions in the thickness direction of the respective constituent layers. The composition was measured using an Auger spectrometer, and the layer thickness was measured using a scanning electron microscope. In each case, the target composition and the layer thickness were substantially the same as the target composition and the layer thickness. .

Next, the above-described coated tooth cutting tools 1 to 13 according to the present invention.
Among the conventional coated gear cutting tools 1 to 12, the cutting speed (rotation speed) of the hob is 200 m / min (1062r).
pm), feed: 2.0 mm / rev, under high-speed cutting conditions, outer diameter: 100 mm x length: 25 mm
× Number of teeth: 48 teeth and material is JIS / SC
gear cutting made of low alloy steel of r420,
Regarding the pinion cutter, the number of strokes: 750 strokes / min, circumferential feed: 4 mm / stroke, radial feed: 0.01 mm / stroke, and outer diameter: 66 mm x length: 25 mm x
Number of teeth: 31 dimensions and the material is JIS / SCr4
Gears made of 20 low alloy steels were subjected to gear cutting, and the number of gears processed until the maximum flank wear of the cutting edge reached 0.02 mm (service life) was measured. The measurement results are shown in Tables 2 and 3, respectively. The number of gears processed in columns 2 and 3
The marks indicate the results of wet processing (using cutting oil), and the non-marks indicate the results of dry processing (air blow).

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

[0020]

From the results shown in Tables 2 and 3, all of the coated tooth cutting tools 1 to 13 of the present invention, in which the hard coating layer is composed of alternate multiple layers of the first thin layer and the second thin layer, are all low alloy steels. Even when the gear cutting process is performed at high speed with high heat generation, the affinity of the high-temperature heated chips to the hard coating layer becomes extremely low due to the remarkable improvement of the chip lubrication by the second thin layer. Since the cutting edge always maintains excellent surface lubricity without welding to the hard coating layer, chipping due to chip welding to the cutting edge does not occur on the cutting edge and excellent wear resistance On the other hand, in the conventional coated tooth cutting tools 1 to 12 in which the hard coating layer substantially consists of a single layer having the same composition as the first thin layer, chips are easily welded to the hard coating layer. Because of this, the hard coating layer is peeled off locally, Mappings occurs, it is apparent that lead to a relatively short time service life. As described above, the coated gear cutting tool of the present invention is not only gear cutting under normal conditions for gears such as carbon steel or cast iron, but also has a particularly high viscosity,
Even in high-speed gear cutting of gears such as low alloy steel and mild steel in which cutting chips easily adhere to the cutting blade surface, it exhibits excellent surface lubricity against chips and exhibits versatile cutting performance. ,
The present invention can satisfactorily cope with the use of the FA in the gear processing device, the labor saving and the energy saving of the gear cutting, and the cost reduction.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view of an arc ion plating apparatus.

Continuing from the front page (72) Inventor Koichi Maeda 179 Kanegasaki Nishi-Oike, Uozumi-cho, Akashi-shi, Hyogo 1 MMC Kobelco Tool Inc. (72) Inventor Yusuke Tanaka 179, Kanegasaki-Nishi-Oike, Uozumi-cho, Akashi-shi, Hyogo 1 FMC term in MMC Belco Tool Co., Ltd. (reference) 3C046 FF02 FF10 FF16 FF19 FF25 4K029 AA02 BA54 BA58 BB02 BC00 BD05 CA04 DB04 DD06 EA01

Claims (1)

[Claims] 1. A high-speed tool steel substrate having a surface of 2 to 15 μm
The hard coating layer physically vapor-deposited with a total average layer thickness of m comprises an alternate lamination of a first thin layer and a second thin layer, each of which has an average layer thickness of 0.005 to 0.2 μm. the composition formula: when represented by _{[Ti 1-X Al X]} N and the _{[Ti 1-X Al X]} C 1- m N m, as measured by Auger spectroscopy apparatus in the thickness direction central portion, the atomic ratio so,
X: 0.30 to 0.70, m: 0.6 to 0.99, which is composed of one or both of a composite nitride of Ti and Al and a composite carbonitride of Ti and Al, The second thin layer is formed by a composition formula: [Ti _{1- (X + Y)} Al _X Ta _Y ]
When expressed in N and the _{[Ti 1- (X + Y)} Al X Ta Y] C 1-m N m, as measured by Auger spectroscopy apparatus in the thickness direction central portion, in terms of atomic ratio, X: 0.30 ~ 0.70, Y:
Composite nitride of Ti, Al and Ta and Ti, Al and Ta satisfying 0.01 to 0.35, m: 0.6 to 0.99
A surface-coated high-speed tool steel gear cutting tool having an excellent chip lubrication property, wherein the hard coating layer has excellent chip lubricity, characterized in that the tool is made of any one or both of the following composite carbonitrides.