JP3353597B2 - Manufacturing method of surface coated cemented carbide cutting tool with excellent chipping resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an Al ₂ O ₃ -based compound layer comprising aluminum oxide (hereinafter, referred to as Al ₂ O ₃ ) as a main component of a hard coating layer. The layer thickness becomes uniform and shows excellent interlayer adhesion to other constituent layers. Therefore, for example, not only continuous cutting of steel or cast iron, but also chipping (particularly when used for intermittent cutting). 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 over a long period of time without occurrence of minute chipping or the like.

[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). (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, the 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, and this is deposited on the reaction surface. Thus, the reaction mechanism in which an Al ₂ O ₃ layer is formed is taken, so that the reaction gas flow and the shape of the reaction surface are affected. Regardless of the arrangement in any state, it is not possible to form an Al ₂ O ₃ layer having a uniform thickness on the flank of the cutting edge, the rake face, and the edge where the flank and the rake face intersect. Difficult and inevitable large thickness variations.

(B) From the results of the above-mentioned study (A), it was concluded that the layer thickness could be made uniform by forming Al ₂ O ₃ on the reaction surface as much as possible. After making efforts to develop a reaction gas for the reaction, AlCl ₃ : 0.5 to 10%, nitrogen oxide (hereinafter referred to as NO _x ): 1 to 30%, titanium tetrachloride (hereinafter, TiCl ₄ ) Shown): 0.01 to
1% hydrogen (hereinafter, indicated by H _2): 0.5~20%, [provided that the proportion of AlCl ₃ for the TiCl _4:. 10 to
100), Ar or He: remainder, the use of Ar or He system reaction gas having a composition consisting of, NO _x is by the catalytic action of TiCl ₄ on the reaction _{surface, NO x → N 2 + O} (a) above (a (In this case, TiCl
_{If 4} does not exist, the reaction becomes NO _x → N ₂ + O ₂ ,
This reaction is a very slow reaction), O generated by the reaction of the above formula (a) is adsorbed on the reaction surface, and thus, the reaction between O and AlCl ₃ becomes AlCl ₃ + O → Al ₂ O ₃ + Cl ₂ (b The reaction is carried out on the reaction surface according to the reaction formula of the above formula (b), and therefore, the layer is formed without moving and depositing the generated Al ₂ O _{3 on} the reaction surface, and the flow of the reaction gas and the reaction surface shape. Is performed without being affected by
_{Since the} reaction atmosphere is activated by the presence of _2, the reactions of the above formulas (a) and (b) are promoted,
The deposited layer formed as a result has very little local variation even when the layer thickness is increased, and furthermore, the adhesion to the reaction surface is further improved, and the deposited layer is made of Al ₂ O ₃ . As a main component, that is, a content of a reaction gas component other than Al and oxygen is 15% or less,
Since it is desirably composed of an Al ₂ O ₃ -based compound layer of 10% or less, it has oxidation resistance, thermal stability, and high hardness equivalent to those of Al ₂ O ₃ .

The present invention has been made on the basis of the above-mentioned research results, wherein Al ₂ O ₃ is used as a main component on the surface of a superhard substrate by using a chemical vapor deposition method and / or a physical vapor deposition method. Hard coating layers including Al ₂ O ₃ -based compound layers, such as TiC layers, TiN layers, TiCN layers, TiO ₂ layers, TiC
The coated super hard layer is formed by forming one or more of the O layer, the TiNO layer, and the TiCNO layer and the Al ₂ O ₃ -based compound layer with an average layer thickness of 3 to 20 μm. In a method of manufacturing a tool, the Al ₂ O ₃ -based compound layer constituting the hard coating layer is used as a reaction gas, AlCl ₃ : 0.5 to 10%, NO _x : 1 to 30%, TiCl ₄ : 0 _{.01~1%, H 2: 0.5~20%} , [ provided that the proportion of AlCl ₃ for the TiCl _4:. 10 to
100], Ar or He: rest, using Ar or He-based reactive gas having a composition consisting of, and reaction temperature: 850 to 1100 ° C., atmospheric pressure: by forming at 20～200Torr, conditions, thick The present invention is characterized by a method for producing a coated cemented carbide tool which achieves uniform layer thickness of the oxidized layer and improvement of the 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) If the proportion of AlCl ₃ is less than 0.5%, the Al source of Al ₂ O ₃ is insufficient and the formation of the Al ₂ O ₃ -based compound layer is slowed down, which is not practical. Is exceeded, the supply of the Al source becomes excessive, and the crystallinity of the Al ₂ O ₃ -based compound layer (deposited layer) is reduced.
0%, preferably 2 to 7%.

[0008] (b) NO _x in the ratio is less than 1%, A with respect to O source of Al ₂ O ₃
The l source is oversupplied and the crystallinity of the deposited layer is reduced.
Is present in excess, causing local non-uniformity in the reaction of the above formula (b), leading to a reduction in the uniformity of the layer thickness.
The ratio was set to 1 to 30%, preferably 5 to 20%.

(C) TiCl_Four If the proportion is less than 0.01%, the reaction of the above formula (a)
Not enough, Al _Two O_Three Supply of O source is insufficient
Not only cannot form a layer at a practical speed, but also
Layer thickness uniformity is also impaired, while the proportion
If it exceeds 1%, a large amount of Ti will be present in the reaction atmosphere.
This causes the crystallinity of the deposited layer to decrease.
From 0.01 to 1%, preferably 0.1 to 1%
It was determined to be 0.5%.

(D) If the proportion of H ₂ is less than 0.5%, the desired activation cannot be achieved in the reaction atmosphere, while if the proportion exceeds 20%, the thickness of the deposited layer becomes inadequate. Since uniformity appears, the proportion is 0.5 to 20%, preferably 1 to 10%.
%.

[0011] (e) capacity ratio of TiCl ₄ AlCl ₃ for (AlCl ₃ / TiCl ₄₎ in the ratio is less than 10, too many proportions of Ti source to the Al source in the reaction atmosphere, this is the crystallinity of the deposited layer Due to the decrease, the predetermined characteristics cannot be secured in the Al ₂ O ₃ -based compound layer.
If it exceeds 0, on the contrary, the proportion of Ti in the reaction atmosphere becomes too small, the decomposition effect of NO _x on the reaction surface by Ti is remarkably reduced, and the supply of the O source of Al ₂ O ₃ becomes insufficient,
Since the layer formation speed is reduced, the ratio is 10 to 10
0, preferably 10 to 50.

Incidentally, the reaction temperature and the other production conditions such as reaction temperature and
And atmospheric pressure, the reaction temperature: 850 to 1100 ° C.
Preferably, 900 to 1050 ° C, atmospheric pressure: 20 to 20
0 torr, preferably 40 to 100 torr
Is good. This is because when the reaction temperature is lower than 850 ° C.,
The crystallinity decreases, while if it exceeds 1100 ° C., Al_Two O _Three 
The system compound layer becomes coarse and wear resistance decreases
And the atmospheric pressure is 20t
If the reaction rate is lower than orr, the reaction becomes slow, and the layer is formed at a predetermined speed.
Is not carried out, while if it exceeds 200 torr, Al_Two O_Three 
Unevenness occurs on the surface of the system compound layer, and
This is because it causes uniformity. Ma
Further, the reason why the average layer thickness of the hard coating layer is set to 3 to 20 μm is as follows.
If the layer thickness is less than 3 μm, the desired excellent wear resistance is ensured.
Cannot be maintained, while its layer thickness exceeds 20 μm
The chipping and chipping of the cutting edge
This is due to reasons.

[0013]

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 composition shown in Table 1, wet-mixed in a ball mill for 72 hours, 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 slowly carburized.
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 super-hard 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).
And p-TiCN has a normal granular crystal structure described in Japanese Unexamined Patent Application Publication No. H10-260, and Table 3 [Al ₂ O ₃ (a) to
(N) shows an Al ₂ O ₃ -based compound layer, and Al ₂ O 3
₃ (o) shows an Al ₂ O ₃ layer. Hereinafter, the same applies to Tables 4 and 5], by forming a hard coating layer having the composition and the target layer thickness (the flank of the cutting edge) shown in Tables 4 and 5 under the conditions shown in Tables 4 and 5. And the conventional methods 1 to 10 are respectively carried out, and coated carbide tools (hereinafter, coated carbide tools corresponding to the respective methods are referred to as coated carbide tools 1 to 14 of the present invention and conventional coated carbide tools 1 to 10). Manufactured. The Al ₂ O ₃ -based compound layer and the Al ₂ O ₃ layer constituting the hard coating layers of the various coated carbide tools obtained as a result (Tables 6 and 7)
In the following, these are collectively referred to as an Al ₂ O ₃ layer), and the maximum layer thickness at the edge where the flank of the cutting edge and the rake face intersect is measured. And the layer thickness at the rake face were measured. The measurement results are shown in Tables 6 and 7. The layer thicknesses of the Al ₂ O ₃ -based compound layer and the other layers other than the Al ₂ O ₃ layer constituting the hard coating layer have almost no local variation and show almost the same value as the target layer thickness. Was something.

Further, in order to evaluate the chipping resistance, the coated carbide tools 1 to 3 of the present invention and the conventionally coated carbide tools 1 and 2 were subjected to a work material: JIS FCD.
450 square bar, cutting speed: 180 m / min. , Depth of cut: 2 mm, feed: 0.3 mm / rev. , Cutting time:
An intermittent cutting test of ductile cast iron was performed under the conditions of 15 minutes, and the flank wear width of the cutting edge was measured.

The coated carbide tools 4 to 6 of the present invention and the conventionally coated carbide tools 3 and 4 are described in Japanese Patent Laid-Open No.
Square material of SCM440, cutting speed: 180 m / min. ,
Cut: 2 mm. , Feed: 0.3 mm / rev. A dry intermittent cutting test of the alloy steel was performed under the conditions of cutting time: 15 minutes, and the flank wear width of the cutting edge was measured.

Similarly, for the coated cutting tools 7 to 9 of the present invention and the conventional coated cutting tools 5 and 6, the work material: JI
S.S45C square bar, cutting speed: 180 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: 15 minutes, and the flank wear width of the cutting edge was measured.

Similarly, for the coated cutting tools 10 to 12 of the present invention and the conventional coated cutting tools 7 and 8, a work material: JIS
-Square bar of FC200, cutting speed: 180 m / min. ,
Cut: 2 mm. , Feed: 0.3 mm / rev. A dry intermittent cutting test of cast iron was performed under the conditions of cutting time: 15 minutes, and the flank wear width of the cutting edge was measured.

Further, the coated cutting tool of the present invention 13-1
5 and the conventional coated cutting tools 9 and 10, the work material: JI having dimensions of width 100 mm × length 500 mm
Square material of S / SNCM439, use condition: 125mm in diameter
Single cutter attached to a cutter, rotation speed: 510 r. p.
m. , Cutting speed: 200 m / min. , Depth of cut: 2m
m. , 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.

[0020]

[Table 1]

[0021]

[Table 2]

[0022]

[Table 3]

[0023]

[Table 4]

[0024]

[Table 5]

[0025]

[Table 6]

[0026]

[Table 7]

[0027]

According to the results shown in Tables 6 and 7,
Al constituting the hard coating layer_TwoO_ThreeIn forming the base compound layer
Inventive processes 1 to 15 using an active gas-based reaction gas
All of the coated coated carbide tools 1 to 15 of the present invention have this structure.
Al in the hard coating layer to be formed _Two O_Three System compound layer thickness
In addition, even if this is made thicker, local variation is extremely small.
Rake face, rake face, rake face and rake face
The layer thickness between the edges where the
On the other hand, Al_TwoO_ThreeUse hydrogen-based reaction gas for layer formation
Conventional coated carbide tools 1-10 manufactured by conventional methods 1-10
At the flank, rake, and edge
The thickness of each layer is significantly different from each other.
Coated carbide tools 1-15 are intermittent cutting of steel and cast iron,
The Al_TwoO_Three -Based compound layer has excellent interlayer adhesion
Combined with the conventional coated carbide tools 1-10
Clearly shows excellent chipping resistance
It is. As described above, according to the method of the present invention, the rigid
Al constituting the coating layer_Two O_Three Thicker compound layer
Even so, there is very little local variation in the layer thickness,
Manufacture of coated carbide tools with excellent interlayer adhesion
And therefore the resulting coated carbide tool
Is the Al_TwoO_ThreeAl-based compound layer_TwoO_ThreeFeatures equivalent to
Combined with the ability to combine steel and cast iron, for example.
Excellent chip resistance not only for continuous cutting but also for interrupted cutting
Demonstrates excellent cutting performance over a long period of time
So that it contributes to the use of FA in cutting and labor saving.
This brings an industrially useful effect.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takashi Oga 1-297 Kitabukurocho, Omiya City, Saitama Prefecture Mitsubishi Materials Corporation In-house Research Laboratory (56) References Patent 3240914 (JP, B2) Patent 3240915 (JP, B2) ) Patent 3240916 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23B 27/14 B23P 15/28 C23C 16/30-16/40

Claims (2)

(57) [Claims] 1. A hard coating layer containing an aluminum oxide-based compound layer containing aluminum oxide as a main component is formed on a surface of a tungsten carbide-based cemented carbide substrate by a chemical vapor deposition method and / or a physical vapor deposition method in a thickness of 3 to 20 μm. A method for producing a surface-coated cemented carbide cutting tool by forming an average layer thickness of: aluminum oxide trichloride: 0.5 to 10% by volume% as a reaction gas Nitrogen oxide: 1 to 30%, titanium tetrachloride: 0.01 to 1%, hydrogen: 0.5 to 20%, (the ratio of aluminum trichloride to titanium tetrachloride: 10 to 100), Ar or He: rest, using Ar or He-based reactive gas having a composition consisting of, and reaction temperature: 850 to 1100 ° C., atmospheric pressure: 20～200Torr, be formed in the condition Preparation of chipping resistance excellent surface-coated cemented carbide cutting tool, characterized in that. 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
one or more of a carbide layer, a nitride layer, a carbonitride layer, an oxide layer, a carbonate layer, a nitrogen oxide layer, and a carbonitride layer of i, and aluminum oxide as a main component. Hard coating layer comprising an aluminum oxide-based compound layer
A method of manufacturing a surface-coated cemented carbide cutting tool by forming an average layer thickness of 20 μm.
Aluminum trichloride: 0.5 to 10%, nitrogen oxides: 1 to 30%, titanium tetrachloride: 0.01 to 1%, hydrogen: 0.5 to 20%, ratio of aluminum chloride: 10 to 100), Ar or He: rest, using Ar or He-based reactive gas having a composition consisting of, and reaction temperature: 850 to 1100 ° C., atmospheric pressure: 20～200Torr, at conditions A method for producing a surface-coated cemented carbide cutting tool having excellent chipping resistance, characterized by being formed .