JP3291775B2 - Surface coated cutting tool - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cemented carbide or cermet substrate formed by a chemical vapor deposition method on a surface of the substrate.
One kind or two or more kinds of titanium carbide, nitride, carbonitride, carbonate and carbonitride, and at least one aluminum oxide layer The present invention relates to a surface-coated cutting tool having excellent wear resistance and fracture resistance formed by forming a composite hard layer composed of:

[0002]

2. Description of the Related Art Conventionally, a surface-coated cutting tool obtained by coating a surface of a cemented carbide substrate or a cermet substrate with a composite hard layer composed of a titanium compound layer and at least one aluminum oxide layer by a chemical vapor deposition method is known as steel. It is well known that it is used for continuous cutting and interrupted cutting.

[0003] The aluminum oxide layer is superior in wear resistance to the titanium compound layer, but is inferior in adhesion and toughness. Therefore, a titanium compound layer is first formed on the surface of a cemented carbide substrate or a cermet substrate by a chemical vapor deposition method. Coating layers,
An aluminum oxide layer is coated on the titanium compound layer by a chemical vapor deposition method to impart abrasion resistance and toughness of the formed composite hard layer to improve fracture resistance.

As a method of forming the aluminum oxide layer in the composite hard layer by a chemical vapor deposition method, a reaction gas containing 0.01 to 1.0% by volume of hydrogen sulfide gas is used as a normal reaction gas to form the aluminum oxide layer. Methods for improving the growth rate are known. According to this method, since the growth rate of the aluminum oxide layer is improved, the structure change can be prevented without exposing other coating layers and the substrate to high temperatures for a long time, and therefore, it is superior to the conventional coated cutting tools. It is said that a surface-coated cutting tool having high performance can be obtained (for example,
No. 3234).

[0005]

However, in recent years, there has been a strong demand for labor saving and shortening of the cutting process, and accompanying this, high speed continuous heavy cutting such as high feed and high cutting under more severe conditions has been accompanied. However, the conventional hydrogen sulfide gas: 0.01 to 0.3 V
Under such severe conditions, a cutting tool coated with a composite hard layer containing an aluminum oxide layer obtained by chemical vapor deposition using a reactive gas containing ol% does not have abrasion resistance and fracture resistance of the coating layer. At present, it is sufficient and shows only a relatively short service life.

[0006]

Accordingly, the present inventors have conducted research to develop a surface-coated cutting tool coated with a composite hard layer including an aluminum oxide layer which is more excellent in wear resistance and fracture resistance. (1) The conventional WC-based cemented carbide cutting tool or T
An aluminum oxide layer formed on the surface of a cutting tool substrate made of an iCN-based cermet by a chemical vapor deposition method using a reaction gas containing hydrogen sulfide gas: 0.01 to 1.0% by volume has an α-type crystal and is subjected to X-ray diffraction. The ratio of the peak intensity of the (030) plane: I (030) to the peak intensity of the (104) plane: I (104) is I (030) / I (104).
≦ 1 made of aluminum oxide,
The aluminum oxide layer having such a crystal structure does not exhibit sufficient wear resistance and fracture resistance.

(2) The reason is that α-type crystal aluminum oxide having orientation on the (104) plane has a crystallographically higher density than α-type crystal aluminum oxide having orientation on the (030) plane. Low-density α-type crystal aluminum oxide exhibiting orientation on the (104) plane having a low density is (030)
The conventional α-type crystal aluminum oxide layer containing more than the α-type crystal aluminum oxide showing orientation on the surface is considered to not show sufficient wear resistance and chipping resistance,

(3) Therefore, the peak intensity I of the (030) plane in the X-ray diffraction is determined by
(030) is larger than the peak intensity I (104) of the (104) plane in X-ray diffraction, that is, I (03)
0)> I (104), when composed of aluminum oxide of α-type crystal, the wear resistance and fracture resistance are further improved, and the surface-coated cutting tool coated with the composite hard layer containing this aluminum oxide layer is (4) The aluminum oxide layer of the α-type crystal in which I (030)> I (104) is sulfided in a normal chemical vapor deposition reaction gas by a normal chemical vapor deposition method. Hydrogen gas:
0.01-2.0 Vol% and sulfur dioxide gas:
It was found that the reaction gas was formed by using a reaction gas to which 01 to 1.0% by volume was added.

The present invention has been made on the basis of this finding, and a titanium compound layer (Ti
C, TiN, TiCN, TiCO, TiCNO, etc. in a cutting tool coated with a single hard layer or a hard coating layer formed of two or more layers and a composite hard layer formed of at least one aluminum oxide layer. The aluminum oxide layer has an α-type crystal and has a peak intensity of (104) plane in X-ray diffraction: (0) with respect to I (104).
30) The ratio of the plane peak intensity: I (030) is I (03).
0) / I (104)> 1 is characterized by a surface-coated cutting tool made of aluminum oxide.

In order to manufacture the surface-coated cutting tool of the present invention, a cermet cutting tool (including a WC-based cemented carbide cutting tool or the like) having a normal surface ground is used as a substrate.
The surface of the substrate is coated with at least one
It is produced by forming a titanium compound layer, and further forming at least one aluminum oxide layer of the present invention on the titanium compound layer. The aluminum oxide layer is not necessarily the outermost layer, and at least one titanium compound layer may be further coated on the aluminum oxide layer.

In the present invention, I (030) / I (10
4) In order to form an aluminum oxide layer satisfying> 1, H ₂ S gas: 0.01 to 2.0 Vol% in a chemical vapor deposition reaction gas for forming a normal aluminum oxide layer.
And SO ₂ gas: formed by using a reaction gas to which 0.01 to 1.0 Vol% is added, and reacts with H ₂ S gas and SO ₂ gas so that 2H ₂ S + SO ₂ = 3S + 2H ₂ O. To produce S and water, and the generated water reacts with aluminum chloride to form H ₂ O + 2AlCl = Al ₂ O ₃ + 6HCl, where Al ₂ is such that I (030) / I (104)> 1. It is believed that O ₃ is produced.

[0012]

Next, a method for manufacturing a surface-coated cutting tool according to the present invention will be specifically described with reference to examples. 72% WC-8% TiC-10% TaC manufactured by ordinary powder metallurgy
A cutting tool having a component composition of -10% Co (corresponding to ISO standard P30) and having a shape defined by ISO standard SNMG432 was prepared.

Example 1 This cutting tool was charged into a conventional chemical vapor deposition apparatus, and the temperature was set at 1: 1.
000 ° C, pressure: 50 torr, reaction gas composition: 3% TiC
Thickness: 3 μm under the condition of l ₄ -9% CH ₄ -88% H ₂ .
A TiC layer having a temperature of 1000 ° C., a pressure of 100 torr, and a reaction gas composition of 4% TiCl ₄ -2%
A TiCNO layer having a thickness of 0.5 μm is formed under the conditions of CO-2% CH ₄ -22% N ₂ -70% H ₂ , and further, a temperature: 1000 ° C., a pressure: 50 torr, and a reaction gas composition : 6% AlCl ₃ -10% CO ₂ -6% HCl-2%
_{H 2 S-1% SO 2} -75% H 2, conditions with a thickness of: 4 [mu]
An Al ₂ O ₃ layer of m was formed to produce a coated cutting tool 1 of the present invention.

Conventional Example 1 After forming a TiC layer and a TiCNO layer under the same conditions as in Example 1, temperature: 1000 ° C., pressure: 50 torr, reaction gas composition: 6% AlCl ₃ -10% CO ₂ -6% HCl—
An Al ₂ O ₃ layer having a thickness of 4 μm was formed under the conditions of 1.0% H ₂ S-77% H ₂ , and a conventional coated cutting tool 1 was produced.

Example 2 The above cutting tool was charged into a conventional chemical vapor deposition apparatus, and the temperature was 1: 1.
000 ° C, pressure: 50 torr, reaction gas composition: 3% TiC
A TiCN layer having a thickness of 4 μm is formed under the conditions of l ₄ -6% CH ₄ -26% N ₂ -65% H ₂ , and a temperature:
1000 ° C., pressure: 50 torr, reaction gas composition: 3% Ti
Cl ₄ -9% CH ₄ -88% H ₂ , thickness: 1 μm
m of a TiC layer, and a temperature of 1000 ° C.
Pressure: 100 torr, reaction gas composition: 4% TiCl ₄ -2
% CO-2% CH ₄ -22% N ₂ -70% H ₂ , a TiCNO layer having a thickness of 0.5 μm is formed, and a temperature of 1000 ° C., a pressure of 50 torr and a reaction gas are further formed thereon. Composition: 6% AlCl ₃ -10% CO ₂ -6% HCl—
An Al ₂ O ₃ layer having a thickness of 3 μm was formed under the conditions of 0.6% H ₂ S−0.3% SO ₂ −77.1% H ₂ , thereby producing a coated cutting tool 2 of the present invention.

Conventional Example 2 A TiCN layer, a TiC layer and a Ti
After forming the CNO layer, temperature: 1000 ° C., pressure: 50
torr, reaction gas composition: 6% AlCl ₃ -10% CO ₂ −
An Al ₂ O ₃ layer having a thickness of 3 μm was formed under the conditions of 6% HCl-0.3% H ₂ S-77.7% H ₂ , and a conventional coated cutting tool 2 was produced.

Example 3 This cutting tool was charged in a conventional chemical vapor deposition apparatus, and the temperature was 1: 1.
000 ° C, pressure: 50 torr, reaction gas composition: 3% TiC
_{l 4 -9% CH 4 -88%} H 2, conditions with a thickness of: 1 [mu] m
A TiC layer having a temperature of 1000 ° C., a pressure of 100 torr, and a reaction gas composition of 4% TiCl ₄ -6%
0.5 μm TiC under the condition of CO-90% H ₂ .
An O layer is formed, and a temperature: 1000 ° C., a pressure: 50 torr, and a reaction gas composition: 6% AlCl ₃ -10%
CO ₂ -6% HCl-1% H ₂ S-0.5% SO ₂ -7
An Al ₂ O ₃ layer having a thickness of 3 μm was formed under the condition of 6.5% H ₂ , thereby producing a coated cutting tool 3 of the present invention.

Under the same conditions as in Example 3, the TiC layer and Ti
After forming the CO layer, temperature: 1000 ° C., pressure: 50 to
rr, reaction gas composition: 6% AlCl ₃ -10% CO ₂ -6
An Al ₂ O ₃ layer having a thickness of 3 μm was formed under the conditions of% HCl-0.5% H ₂ S-77.5% H ₂ , and a conventional coated cutting tool 3 was produced.

Examples 4-6 A of the coated cutting tools 1-3 of the present invention produced in Examples 1-3.
on the surface of the l ₂ O ₃ layer, further temperature: 1000 ° C., pressure:
200 torr, reaction gas composition: 2% TiCl ₄ -38% N
A TiN layer having a thickness of 1 μm was formed under the conditions of _{2 to} 60% H ₂ , thereby producing coated cutting tools 4 to 6 of the present invention.

On the surface of the Al ₂ O ₃ layer of each of the conventional coated cutting tools 1 to 3 produced in Conventional Examples 1 to 3, a temperature of 1000 was further added.
° C, pressure: 200 torr, reaction gas composition: 2% TiCl ₄
-38% N ₂ -60% H ₂ , thickness: 1 μm T
An iN layer was formed, and conventionally coated cutting tools 4 to 6 were produced.

X-ray diffraction was performed on these coated cutting tools 1 to 6 of the present invention and conventional coated cutting tools 1 to 6,
(104) plane peak intensity: (0) with respect to I (104)
30) plane peak intensity: ratio of I (030) = I (03)
0) / I (104) was determined, and their values are shown in Table 1.

[0022] The present invention coated cutting tool 6 and the conventional coated cutting tools 1 to 6 were obtained, Workpiece: SNCM439 (Hardness: H _B 230) Cutting speed: 180 m / min feed Ri: 0.3 mm / rev Depth of cut: 2.0 mm Cutting time: 30 min Cooling oil: None A continuous cutting test of steel was performed, and the flank wear width of the cutting edge was measured. These results are also shown in Table 1.

Furthermore, the present invention coated cutting the tool 6 and the conventional coated cutting tools 1 to 6, Workpiece: SNCM439 (Hardness: H _B 230) square bar Cutting speed: 100 m / min feed Ri: 0.236mm / rev Depth of cut: 3.0 mm Cutting time: 30 min Cooling oil: None An intermittent cutting test was performed on the steel, and the time until the cutting edge of the tool reached fracture was measured. The results are also shown in Table 1.

[0023]

[Table 1]

[0024]

As is evident from the results shown in Table 1, the I (0) of the Al ₂ O ₃ layer of the coated cutting tools 1 to 6 of the present invention.
The values of 30) / I (104) are all greater than 1, but I (03) of the Al ₂ O ₃ layer of the conventional coated cutting tools 1-6.
0) / I (104) is 1 or less, and I (030) / I (10) of the Al ₂ O ₃ layer coated on the substrate.
The coated cutting tools 1 to 6 of the present invention in which the value of 4) is larger than 1 have a smaller flank wear width when a continuous cutting test is performed than the conventional coated cutting tools 1 to 6 and are less likely to suffer defects caused by an intermittent cutting test. It can be seen that the time until the solstice is long.

Therefore, the surface-coated cutting tool of the present invention has a cutting performance which is more excellent than that of the conventional surface-coated cutting tool. It can be reduced and can greatly contribute to the development of industry.

──────────────────────────────────────────────────の Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B23B 27/14 B23P 15/28 C23C 16/30-16/40 C23C 28/04

Claims (1)

(57) [Claims] Claims: 1. A titanium carbide, nitride,
A cutting tool coated with a single hard layer of carbonitrides, carbon oxides and carbonitrides, or a composite hard layer comprising at least one aluminum oxide layer; The aluminum layer has an α-type crystal and the ratio of the peak intensity of the (030) plane: I (030) to the peak intensity of the (104) plane: I (104) by X-ray diffraction is I (030) / A surface-coated cutting tool comprising an aluminum oxide such that I (104)> 1.