JPS6155591B2 - - Google Patents

Description

[Detailed description of the invention]

This invention provides a surface coating that exhibits excellent cutting performance when used as a cutting tool for cutting steel and cast iron, especially for heavy cutting such as high-speed cutting, high-feed cutting, and deep-cut cutting of both of these work materials. The present invention relates to a method for manufacturing an ultra-hard sintered member. Conventionally, the base member is generally a super-hard sintered member made of a cermet such as a tungsten carbide-based cemented carbide or a titanium carbide-based sintered material, or a ceramic such as an aluminum oxide-based sintered material.
A single or double layer of one of the group consisting of carbides, nitrides, and oxides of metals from groups 4a, 5a, and 6a of the periodic table, and solid solutions of two or more of these metals is coated on the surface of this base member. It is well known that a surface-coated ultra-hard sintered member formed by forming a coating layer consisting of more than one layer by a chemical vapor deposition method or the like is used as a cutting tool. However, although some of these conventional surface-coated ultra-hard sintered members show excellent cutting performance when used for cutting steel, they do not show the desired cutting performance when cutting cast iron, and it takes a relatively short time. Others, on the contrary, show excellent performance and a relatively long service life when cutting cast iron, but have a short cutting life when cutting steel. It does not exhibit satisfactory cutting performance when cutting either steel or cast iron such as paddles, and even more so when cutting these materials at high speeds or during heavy cutting such as high-feed cutting and deep-cut cutting. Of course, this is true when cutting under such conditions. Therefore, from the above-mentioned viewpoint, the inventors of the present invention have found that it can be used not only for cutting both steel and cast iron, but also under severe conditions such as high-speed cutting and heavy cutting of both these work materials. As a result of research to develop a cutting tool that exhibits excellent cutting performance even when cutting Charged into a container, AlCl ₃ , Al(CH ₃ ) ₃ , and Al ₂ (CH ₃ ) ₃ Cl ₃ in volume %
One of these (hereinafter collectively referred to as Al source): 0.5 to 5%, one or two of CO ₂ and CO: 3 to 5%
15%, or one or two of CO ₂ and CO, and hydrocarbon gas: 3 to 15% (however, hydrocarbon gas: 0.3 to 5%, hereinafter collectively referred to as carbon/oxygen supply source) ), N ₂ : 10 to 30%, Ar: 30 to 70%, H ₂ : remainder (but containing 10% or more), while introducing a reaction mixture gas having the following composition: Atmosphere inside the reaction vessel: 0.1 Plasma chemical vapor deposition treatment under the following conditions: vacuum of ~20 torr, application of DC voltage to the base member: -300 to -800 V, or high frequency power of 0.2 to 10 W/ ^cm2 , heating temperature in the reaction vessel: 800 to 1200°C. When this is carried out, a hard coating layer made of crystalline aluminum carbonitride oxide (hereinafter referred to as Al CNO) is formed on the surface of the base member, and this Al CNO has high hardness at room temperature and high temperature. The resulting Al CNO
Surface-coated ultra-hard sintered parts with a hard coating layer exhibit excellent performance when used as cutting tools for cutting steel and cast iron, and furthermore, they can be used for high-speed cutting and heavy-duty cutting of both of the work materials mentioned above. They found that even when used for cutting, it similarly exhibits excellent cutting performance and can ensure a long service life. This invention was made based on the above knowledge, and the reason why the manufacturing conditions were limited as described above will be explained below. (a) Composition of reaction mixture Al source, carbon/oxygen source, and N ₂ The blending amounts of these components are respectively less than 0.5% for Al source, less than 3% for carbon/oxygen source,
and N ₂ : less than 10%, it is not possible to form a crystalline Al/CNO hard coating layer on the surface of the base member at a practical reaction rate; on the other hand, if the blending amount of the Al source exceeds 5%, The reaction within the glow discharge becomes active and begins to form Al/CNO powder.
It becomes difficult to form an Al CNO hard coating layer firmly deposited on the surface of the base member, and if the carbon/oxygen supply source exceeds 15% or _N2 exceeds 30%, the AlCNO hard coating layer becomes difficult to form. Al ₂ O ₃ and
As AlN becomes mixed, the properties of the coating layer deteriorate, so the respective blending amounts are changed to 0.5 to 5% for Al source, 3 to 15% for carbon/oxygen source, and 3 to 15% for carbon/oxygen source. _N2 : was set at 10-30%.
Note that hydrocarbon gas is C in the AlCNO hard coating layer.
It is added when it is necessary to relatively increase the content of the ingredients, but if the amount added is less than 0.3%, the effect will not appear, while if it is added more than 5%, graphite (carbon) will precipitate. As a result, the properties of the hard coating layer also deteriorate.
The blending amount of hydrocarbon gas was determined to be 0.3 to 5%. Ar Ar gas has the effect of promoting glow discharge, but if the amount is less than 30%, the desired glow discharge cannot be achieved, while if it is more than 70%, the glow discharge becomes too active. As a result, the surface temperature of the base member becomes too high, exceeding 1200°C, and the crystal grains of the hard coating layer become coarse and brittle, so the amount of the hard coating layer is reduced to 30 to 70%.
It was determined that Note that if the amount of H ₂ is less than 10%, the reduction of the Al supply source will not be sufficient, and as a result, it will take a long time to form _the AlCNO hard coating layer. % or more. (b) Pressure of the atmosphere inside the reaction vessel If the pressure is less than 0.1 torr, the reaction rate is extremely slow and it is not practical.On the other hand, if the pressure is made to exceed 20 torr, reactions occur in the atmosphere and amorphous The pressure was determined to be 0.1 to 20 torr because quality AlCNO powder was formed. (c) Application to the base member When the application to the base member is DC voltage: -
For less than 300V and high frequency power: less than 0.2W/ ^cm2 , the glow discharge is extremely weak and the desired AlCNO
A coating layer cannot be formed, and on the other hand, DC voltage is -800V, and high frequency power is 10W/
cm ² , the temperature of the base member increases to 1200℃
If the voltage becomes too high and the crystal grain growth that causes embrittlement becomes significant, the voltage applied to the base member should be changed to -300 to -800 V for DC voltage and 0.2 to 10 W/cm for high frequency power. ² . (d) Heating temperature in the reaction vessel If the heating temperature is less than 800°C, the AlCNO coating layer becomes amorphous and cannot form a crystalline form, whereas if the heating temperature exceeds 1200°C,
As mentioned above, grain growth that causes embrittlement
Since this occurs in the AlCNO coating layer, the heating temperature was set at 800-1200°C. In addition, formed by the method of this invention
It can be easily confirmed by X-ray diffraction measurement that the AlCNO hard coating layer has a crystalline form, and furthermore, the atomic ratio is Al _{0.55 ~ 0.61} C _{0.15 ~ 0.22} N _{0.02 ~} It has a composition _{of 0.08 O 0.13 to 0.20} . Furthermore, when forming the AlCNO coating layer by the method of this invention, the average layer thickness is 0.5 to
The average layer thickness is preferably 20 μm, because if the average layer thickness is less than 0.5 μm, the desired excellent cutting performance cannot be achieved over a long period of time;
This is because if the layer thickness exceeds 100%, the coating process time becomes longer, which not only causes the crystals to become coarser and reduce toughness, but also causes the surface to become rough and uneven. be. Next, the method for manufacturing the surface-coated ultra-hard sintered member of the present invention will be specifically explained with reference to Examples. Example A cutting tip made of an ultra-hard sintered material and a cutting tip made of a surface-coated ultra-hard sintered material each having the composition and coating layer shown in Table 1 were prepared as the base member, and these base members were each prepared in a normal manner. The base member is charged into a reaction vessel of a plasma chemical vapor deposition apparatus, and then subjected to plasma chemical vapor deposition treatment under the conditions shown in Table 1 to coat the surface of the base member with AlCNO.
Surface-coated cutting chips 1 to 12 of the present invention were each manufactured by forming a hard coating layer. Next, the composition of the AlCNO coating layer in the surface-coated cutting chips 1 to 12 of the present invention obtained as a result,
The crystal shape, Vickers hardness, and average layer thickness were measured and the results are also shown in Table 1. Furthermore, the above-mentioned surface-coated cutting chips 1 to 1 of the present invention
Regarding 12,

【table】

【table】

[Table] Work material: SNCM-8 (Hardness: H _B 270), Cutting speed: 160 m/min, Feed: 0.34 mm/rev., Depth of cut: 1.5 mm, Cutting time: 30 min. High-speed cutting test and the following conditions: Work material: FC-25 (Hardness: _HB 200), Cutting speed: 200 m/min, Feed: 0.25 mm/rev., Depth of cut: 1.5 mm, Cutting time: 20 min. A high-speed cutting test was conducted on cast iron, and the flank wear width of the cutting edge was measured after the test. The results of these measurements are shown in Table 2. Table 2 also shows, for comparison purposes, the surface-coated cutting chips 1 to 1 of the present invention.
In No. 12, the cutting test results under the same conditions of the base members (hereinafter referred to as conventional cutting chips 1 to 12) before forming the AlCNO coating layer are also shown. From the results shown in Table 2, surface-coated cutting chips 1 to 12 of the present invention are superior to conventional cutting chips 1 to 12, which are the same except that they do not form an AlCNO hard coating layer, in high-speed cutting of both steel and cast iron. It shows much better wear resistance compared to
It is clear that this is caused by the formation of the AlCNO hard coating layer. As described above, according to the method of the present invention, a material having high hardness and toughness at room temperature and high temperature, and chemically stable at high temperature.
An AlCNO hard coating layer can be formed on the surface of the base member. Therefore, when a surface-coated ultra-hard sintered member having this AlCNO hard coating layer is used as a cutting tool for cutting steel and cast iron, it has excellent performance. Furthermore, it stably exhibits extremely excellent cutting performance over a long period of time, even in high-speed cutting and heavy cutting of steel and cast iron, which require cutting under even harsher conditions.

Claims (1)

[Scope of Claims] 1. An ultra-hard sintered member made of cermet or ceramics, or a surface-coated ultra-hard sintered member formed by forming a hard layer on the surface of the ultra-hard sintered member, as a base member; The base member is charged into a reaction vessel, and one of _AlCl3 , Al( _CH3 ) ₃ , and _Al2 ( _CH3 ) _3Cl3 : 0.5 to 5%, _CO2 and CO _are added in volume %. One or two of the following: 3~
15%, or one or two of CO ₂ and CO, hydrocarbon gas: 3 to 15% (contains hydrocarbon gas: 0.3 to 5%), N ₂ : 10 to 30%, Ar: 30 While introducing a reaction mixture gas having a composition consisting of ~70%, _H2 : the remainder (containing 10% or more), atmosphere inside the reaction vessel: vacuum of 0.1 to 20 torr, application to the base member: -300 to By performing plasma chemical vapor deposition treatment under the following conditions: -800V DC voltage or 0.2~10W/ ^cm2 high frequency power, reaction vessel heating temperature: 800~1200℃, the surface of the base member is coated with A method for producing a surface-coated ultra-hard sintered member for a cutting tool, which comprises forming a hard coating layer made of crystalline aluminum carbonitride.