JPH108253A - Manufacturing method of surface coated cemented carbide cutting tool with excellent chipping resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a cutting tool made of surface coated cemented carbide excellent in chipping resistance and showing excellent cuttability over a long period. SOLUTION: At the time of producing a cutting tool made of surface coated cemented carbide by forming a hard coating layer with 3 to 20μm average layer thickness contg. an Al2 O3 layer on the surface of a WC base cemented carbide substrate using a chemical vapor deposition method and/or a physical vapor deposition method, in the formation of the above Al2 O3 layer, as the reactive gas, an inert reactive gas having a compsn. composed of, by volume, 0.5 to 10% AlCl3 , 1 to 30% sulfur oxide (where y/x>2 in the case of being expressed by the compositional formula of Sx Oy , and the balance inert gas is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention, aluminum oxide which constitutes the hard coating layer (hereinafter, indicated by Al ₂ O ₃₎ layer relatively fast deposition rate, and can be formed into a thick film, Moreover, even if this is made thicker, the layer thickness becomes uniform,
In addition, since it shows excellent interlayer adhesion to other constituent layers, it can be used not only for continuous cutting of steel or cast iron, for example, but also for intermittent cutting, especially when used for chipping (minute chipping) on the cutting edge. The present invention relates to a method for producing a surface-coated cemented carbide cutting tool (hereinafter referred to as a coated cemented carbide tool) that exhibits excellent cutting performance for a long period of time without occurrence of cracks.

[0002]

2. Description of the Related Art Conventionally, a hard coating layer including an Al ₂ O ₃ layer is formed on a surface of a tungsten carbide-based cemented carbide substrate (hereinafter referred to as a cemented carbide substrate) by using a chemical vapor deposition method and / or a physical vapor deposition method. For example, a carbide of Ti (hereinafter, referred to as TiC)
Layer, nitride (hereinafter also indicated as TiN) layer, carbonitride (hereinafter indicated as TiCN) layer, oxide (hereinafter referred to as TiO ₂₎
) Layer, a carbonate (hereinafter, shown as TiCO) layer, a nitrogen oxide (hereinafter, shown as TiNO) layer, and one or more of a carbon oxynitride (hereinafter, shown as TiCNO) layer When the hard coating layer consisting of the Al ₂ O ₃ layer 3-20
A coated carbide tool formed with an average layer thickness of μm is known. Further, in particular, the formation of the Al ₂ O ₃ layer constituting the hard coating layer of the coated cemented carbide tool is considered as a reaction gas,
(Hereinafter,% indicates volume%), aluminum trichloride (hereinafter, shown as AlCl ₃ ): 1 to 20%, carbon dioxide (hereinafter, shown as CO ₂ ): 0.5 to 30%, [ If necessary, carbon monoxide (CO) or hydrogen chloride (HC
l): 1 to 30%], hydrogen: a hydrogen-based reaction gas having a composition consisting of the remainder, and a reaction temperature of 950 to 1100.
It is also known that the process is performed under the conditions of ° C and an atmospheric pressure of 20 to 200 torr.

[0003]

On the other hand, in recent years, the use of FA in cutting has been remarkable, and there has been a strong demand for labor saving. Accordingly, coated carbide tools have been required to have a longer service life. As means corresponding to the above, among the hard coating layers constituting the same, particularly, the oxidation resistance and thermal stability are excellent, and further thickening of an Al ₂ O ₃ layer having high hardness has been widely studied. When the thickness of the Al ₂ O ₃ layer is increased, the thickness of the Al ₂ O ₃ layer becomes locally non-uniform in the conventional Al ₂ O ₃ layer forming means, and the flank of the cutting edge, the rake face, and the rake face Not only does the layer thickness significantly vary between the edges where the surfaces intersect, but also the adhesion to other constituent layers (interlayer adhesion) is reduced, which results in, for example, steel or cast iron. Chipping on cutting edge when used for interrupted cutting such as Easily it occurs, at present, leading to a relatively short time service life.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above viewpoint, when manufacturing coated carbide tools,
In particular, focusing on the formation of the Al ₂ O ₃ layer constituting the hard coating layer, a study was conducted to reduce the local variation of the layer thickness when the layer thickness was increased and to improve the interlayer adhesion. (A) and (b) were obtained. (A) Al formed using a conventional hydrogen-based reaction gas
_{In the 2} O ₃ layer, CO ₂ and hydrogen (H ₂ ), which are constituents of a reaction gas, react in a reaction atmosphere according to the above reaction formula (1), CO ₂ + H ₂ → CO + H ₂ O. The resulting H ₂ O and AlCl ₃ react with AlCl ₃ + H ₂ O → Al ₂ O ₃ + HCl (2) according to the above reaction formula (2), whereby AlCl ₃ is hydrolyzed to form Al ₂ O ₃ And in this case, the above (1)
The reaction of the above formula (2) is much faster than the reaction of the formula,
Therefore, H ₂ O generated by the above formula (1) quickly reacts with AlCl ₃ present in the reaction atmosphere, and most of the Al ₂ O ₃ is generated in the reaction atmosphere. including the formed hard coat layer surface, Al ₂ O by depositing the same hereinafter)
Because it takes a reaction mechanism in which _three layers are formed, it is affected by the flow of the reaction gas and the shape of the surface of the substrate. Even if it is arranged in a state, it is difficult to form an Al ₂ O ₃ layer having a uniform thickness between the flank of the cutting edge, the rake face, and the edge portion where the flank and the rake face intersect, and it is difficult Variations in layer thickness are inevitable.

(B) From the results of the above-mentioned study (a), it has been concluded that the layer thickness can be made uniform by forming Al ₂ O _{3 on the} surface of the substrate as much as possible. When efforts were made to develop a reaction gas for the reaction, AlCl ₃ : 0.5 to 10%, sulfur oxide (provided that the composition formula: S _x O _y , y / x>
2): When an inert gas-based reaction gas having a composition of 1 to 30% and an inert gas: remaining is used, the above-mentioned sulfur oxide in the reaction gas (hereinafter, SO ₃ will be described as an example)
However, SO ₃ → SO ₂ + O (A) is decomposed according to the above equation (A) to generate O. On the other hand, SO ₂ generated at the same time
_Since it acts as a catalyst to accelerate the decomposition of ₃ , Al
Cl ₃ is a substrate surface, decompose according AlCl ₃ → Al + Cl ₂ (b) (a) above equation, to produce Al and Cl _2. Therefore, the Al formed by the above equations (A) and (A)
And O is the substrate surface, and reacted according to _{Al + O → Al 2 O 3} ( c) above (c) formula Al ₂ O ₃ to produce. Here, the reactions of the above formulas (A), (A) and (C) all have a high reaction rate, so that Al ₂ O ₃
Not only the film formation rate of the layer becomes relatively high, but also the reaction of the above formula (c) is carried out on the substrate surface. Therefore, when forming the Al ₂ O ₃ layer, the formed Al ₂ O ₃
Of the reaction gas flow and the shape of the substrate surface, so that the resulting deposited Al ₂ O ₃ layer has a layer thickness of Even when the thickness is increased, local variations are extremely small, and the adhesion to the substrate surface is further improved.

The present invention has been made on the basis of the above-mentioned research results, and a hard coating including an Al ₂ O ₃ layer on a surface of a superhard substrate by using a chemical vapor deposition method and / or a physical vapor deposition method. Layers such as TiC layer, TiN layer, TiCN layer,
TiO ₂ layer, TiCO layer, TiNO layer, and TiCN
A method for producing a coated cemented carbide tool by forming a hard coating layer comprising one or more of the O layers and the Al ₂ O ₃ -based layer with an average layer thickness of 3 to 20 μm,
The formation of the Al ₂ O ₃ layer constituting the hard coating layer is performed by using, as a reaction gas, AlCl ₃ : 0.5 to 10%, sulfur oxide (however, when represented by a composition formula: S _x O _y , y / x >
2): 1 to 30%, inert gas such as Ar or He: remaining, by using an inert gas-based reaction gas having a composition consisting of:
Further, the present invention is characterized by a method for producing a coated cemented carbide tool which achieves uniform layer thickness of the thickened layer and improved interlayer adhesion and, as a result, exhibits excellent chipping resistance.

Next, the reason why the composition of the reaction gas is limited as described above in the method of the present invention will be described. (A) When the proportion of AlCl ₃ is less than 0.5%, the source of Al ₂ O ₃ is insufficient and the formation of the Al ₂ O ₃ layer becomes slow, which is not practical.
On the other hand, if the ratio exceeds 10%, the supply of the Al source becomes excessive, and the crystallinity of the Al ₂ O ₃ layer decreases, so that the ratio is 0.5 to 10%, preferably 2 to 7%. I decided.

(B) Sulfur oxide (hereinafter referred to as S _x O _y ) When the proportion is less than 1%, A is less than the O source of Al ₂ O _3.
If the l-source is excessively supplied and the crystallinity is reduced, on the other hand, if the ratio exceeds 30%, the decomposition O is excessively present relative to the Al source, and the formation rate of the Al ₂ O ₃ layer is reduced. From
The ratio was set to 1 to 30%, preferably 5 to 20%. Further, the atomic ratio of S and O in S _x O _y , that is, y /
When x is 2 or less, since SO ₂ is chemically stable, there is no O generated according to the above formula (A), that is, SO ₃ → SO ₂ + O, and the formation of the Al ₂ O ₃ layer is substantially eliminated. Since it becomes impossible, y / x> 2 was determined.

The reaction temperature and atmospheric pressure, which are other production conditions, are as follows: reaction temperature: 800 to 1100 ° C., preferably 900 to 1050 ° C., and atmospheric pressure: 20 to 20.
0 torr, preferably 40 to 100 torr. This is because when the reaction temperature is lower than 800 ° C., Al ₂ O
The crystallinity of the _three layers decreases, while if it exceeds 1100 ° C, Al
_{This is because the 2} O ₃ layer becomes coarse and the chipping resistance is reduced.
If the pressure is less than 0 torr, the reaction is slow, and the layer is not formed at a predetermined speed. On the other hand, if the pressure exceeds 200 torr, the surface of the layer becomes uneven, which causes a non-uniform layer thickness. It is. Further, the reason why the average layer thickness of the hard coating layer is 3 to 20 μm is that the layer thickness is 3 μm.
If the thickness is less than 20 μm, the desired excellent wear resistance cannot be ensured. On the other hand, if the thickness exceeds 20 μm, chipping or chipping is likely to occur on the cutting edge.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the method of the present invention will be specifically described with reference to embodiments. As raw material powder, average particle size:
Medium WC powder having 2.8 μm, coarse WC powder having 4.9 μm, and (Ti, W) C having 1.5 μm (weight ratio:
Hereinafter the same, TiC / WC = 30/70) powder, same as 1.2
μm (Ti, W) CN (TiC / TiN / WC = 24
/ 20/56) Powder, (Ta, Nb) C of 1.2 μm
(TaC / NbC = 90/10) powder, and 1.1
μm Co powder was prepared, and these raw material powders were blended in the blending composition shown in Table 1, wet-mixed for 72 hours with a ball mill, dried, and then subjected to ISO • CNMG120408 (for carbide substrates A to D) and SEEN42AFTN1. Press-formed into a green compact having a shape defined for (for super-hard substrate E), and the green compact was vacuum-sintered under the conditions shown in Table 1 to produce super-hard substrates A to E, respectively. Further, the cemented carbide substrate B is kept in a 100 Torr CH ₄ gas atmosphere at a temperature of 1400 ° C. for 1 hour, and then gradually carburized. After the treatment, carbon and carbon adhering to the cemented carbide substrate surface are treated.
By removing o by acid and barrel polishing, the maximum Co content at a position 11 μm from the surface: 15.9% by weight,
A Co-enriched zone having a depth of 42 μm was formed on the surface of the substrate. On the surface of the cemented carbide substrates A and D, a Co-enriched zone having a maximum Co content of 9.1 wt% and a depth of 23 μm was formed at a position of 17 μm from the surface of the sintered body. And the remaining cemented carbide substrates C and E have the C
o There was no formation of an enriched zone and the tissue had an overall homogeneous structure. Table 1 shows the internal hardness (Rockwell hardness A scale) of each of the carbide substrates A to E.

Then, the surfaces of these superhard substrates A to E were honed, and a conventional chemical vapor deposition apparatus was used. Table 1 (1-TiCN in the table corresponds to JP-A-6-8010
Under the conditions shown in Table 3 and Table 3 under the conditions shown in Table 3 and under the condition shown in Table 3. By forming the hard coating layer having the composition and the target layer thickness (the flank of the cutting edge), the methods 1 to 10 of the present invention and the conventional methods 1 to 10 are carried out, respectively, and the coated carbide tool (hereinafter, corresponding to each method) Coated carbide tools to be used are referred to as coated carbide tools 1 to 10 of the present invention and conventional coated carbide tools 1 to 10).
Was manufactured. For the resulting Al ₂ O ₃ layer constituting the hard coating layer of the various coated carbide tools obtained as a result, the maximum layer thickness at the edge where the flank and rake face of the cutting edge intersect was measured, and further from the edge. The layer thickness was measured on the flank and rake face of each 1 mm inside. The measurement results are shown in Tables 6 and 7. In addition, Al ₂ O constituting the hard coating layer
_The thicknesses of the other layers other than the _three layers showed almost no local variation, and were almost the same as the target layer thickness.

Further, for the purpose of evaluating chipping resistance, the coated carbide tools 1 and 2 of the present invention and the conventional coated carbide tools 1 and 2 were subjected to a work material: JIS FCD.
45, a cutting speed: 150 m / min. , Infeed:
2 mm, feed: 0.3 mm / rev. , Cutting time: 10
A dry intermittent cutting test of ductile cast iron was performed under the following conditions, and the flank wear width of the cutting edge was measured.

[0013] The coated carbide tools 3 and 4 of the present invention and the conventional coated carbide tools 3 and 4 have a work material of JIS.
Square material of SCM440, cutting speed: 150 m / min. ,
Cut: 2 mm. , Feed: 0.3 mm / rev. A dry intermittent cutting test was performed on the alloy steel under the conditions of cutting time: 10 minutes, and the flank wear width of the cutting edge was measured in the same manner.

Similarly, for the coated carbide tools 5 and 6 of the present invention and the conventionally coated carbide tools 5 and 6, a work material: JI
S.S45C square bar, cutting speed: 150 m / min. ,
Cut: 2 mm. , Feed: 0.3 mm / rev. A dry intermittent cutting test of carbon steel was performed under the conditions of cutting time: 10 minutes, and the flank wear width of the cutting edge was measured.

Similarly, for the coated carbide tools 7 and 8 of the present invention and the conventional coated carbide tools 7 and 8, a work material: JIS F
C200 square bar, cutting speed: 150 m / min. , Cut: 2 mm. , Feed: 0.3 mm / rev. , Cutting time: 10 minutes, dry intermittent cutting test of cast iron,
The flank wear width of the cutting blade was measured.

Further, the same applies to the coated carbide tools 9 and 10 of the present invention.
And for the conventional coated carbide tools 9, 10, the work material:
JIS with dimensions of width 100mm x length 500mm
Square material of SCM440, use conditions: single blade attached to a cutter with a diameter of 125 mm, rotation speed: 510 r. p. m. , Cutting speed: 200 m / min. , Cut: 2 mm. , Feed: 0.2mm / tooth, cutting time: 3 passes (cutting time of 1 pass: 5.3 minutes), dry milling (intermittent cutting) test of alloy steel, flank wear of cutting edge The width was measured. Tables 6 and 7 show the results of these measurements.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

[0020]

[Table 4]

[0021]

[Table 5]

[0022]

[Table 6]

[0023]

[Table 7]

[0024]

As can be seen from the results shown in Tables 6 and 7, all of the books produced by the present invention methods 1 to 10 using an inert gas-based reactive gas for forming the Al ₂ O ₃ layer constituting the hard coating layer. In each of the invention coated carbide tools 1 to 10, even if the thickness of the Al ₂ O ₃ layer of the hard coating layer constituting the hard coating layer is increased, the local variation is extremely small, and the cutting edge escapes. The surface thickness, the rake face, and the layer thickness between the flank and the rake face intersecting edges are made uniform, while Al ₂
Conventional methods 1 to 10 using a hydrogen-based reaction gas for forming the O ₃ layer
In the conventional coated cemented carbide tools 1 to 10 manufactured by the above, the variation in the layer thickness between the flank, the rake face, and the edge portion is remarkable, and as a result, the coated cemented carbide tools 1 to 10 of the present invention and in intermittent cutting of cast iron, the Al ₂
Coupled with the excellent interlayer adhesion of the O ₃ layer,
It is clear that the chipping resistance is superior to that of the conventional coated carbide tools 1 to 10. As described above, according to the method of the present invention, A
Even if the layer thickness of the l ₂ O ₃ layer is increased, a coated carbide tool having very little local variation in the layer thickness and good interlayer adhesion can be manufactured. Coated carbide tools, for example, show excellent chipping resistance even in intermittent cutting as well as continuous cutting of steel and cast iron, etc., and show excellent cutting performance over a long period of time. It has industrially useful effects such as contributing to labor saving.

Claims (2)

[Claims] 1. A hard coating layer including an aluminum oxide layer having an average thickness of 3 to 20 μm is formed on a surface of a tungsten carbide-based cemented carbide substrate using a chemical vapor deposition method and / or a physical vapor deposition method. In a method for producing a surface-coated cemented carbide cutting tool, aluminum trichloride: 0.5 to 10% by volume, as a reactive gas, sulfur oxide (the composition formula: When represented by S _x O _y , y
/ X> 2): 1 to 30%, inert gas: the use of an inert gas-based reactive gas having a composition consisting of the remainder, a cutting tool made of a surface-coated cemented carbide having excellent chipping resistance. Manufacturing method. 2. The surface of a tungsten carbide-based cemented carbide substrate is subjected to chemical vapor deposition and / or physical vapor deposition to form a T
i or one or more of a carbide layer, a nitride layer, a carbonitride layer, an oxide layer, a carbonate layer, a nitride oxide layer, and a carbonitride layer, and an aluminum oxide layer A method of manufacturing a surface-coated cemented carbide cutting tool by forming a hard coating layer with an average layer thickness of 3 to 20 μm. : 0.5 to 10%, sulfur oxide (however, when represented by a composition formula: S _x O _y , y
/ X> 2): 1 to 30%, inert gas: the use of an inert gas-based reactive gas having a composition consisting of the remainder, a cutting tool made of a surface-coated cemented carbide having excellent chipping resistance. Manufacturing method.