JP2001315004A - Surface-coated cermet cutting tool with hard coating layer having superior heat-resisting plastic deformation characteristic - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface-coated cermet cutting tool having a hard coating layer having superior heat-resisting plastic deformation characteristic. SOLUTION: In this surface-coated cermet cutting tool manufactured vapor deposition by forming the hard coating layer of a thickness of 5-30 μm by chemical and/or physical vapor deposition onto a surface of a cermet base composed of tungsten carbide hard metal base or titanium carbonitride cermet base, the hard coating layer is composed of (a) one or plural carbide layer, nitride layer, carbonitride layer, carboxide layer and carbonitroxide layer of Ti, having a granular crystal structure, (b) and aluminum oxide layer similarly having the granular crystal structure, and (c) a composite carbonitride layer of Ti and V including V of 1-30 atom % to the total amount of Ti and V, and having a longitudinal grown crystal structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hard coating for high heat generated when high-speed cutting is performed on difficult-to-cut materials such as stainless steel and mild steel, which exhibit high cutting resistance due to high viscosity of the material. The layer exhibits excellent heat-resistant plastic deformation properties,
The present invention relates to a surface-coated cermet-made cutting tool (hereinafter, referred to as a coated cermet tool) which can exhibit excellent cutting performance for a long period of time because uneven wear is significantly suppressed.

[0002]

2. Description of the Related Art Conventionally, a hard coating layer is generally formed on a surface of a cermet substrate made of a tungsten carbide (hereinafter, referred to as WC) -based cemented carbide substrate or a titanium cermet (hereinafter, referred to as TiCN) -based cermet substrate. Coated cermet tools are known which are chemically and / or physically deposited with an average layer thickness of 〜30 μm.

[0003] In the above coated cermet tool, the hard coating layer is formed of a (a) Ti carbide (hereinafter referred to as TiC) layer and a nitride (hereinafter also referred to as TiN) each having a granular crystal structure. ), A carbonitride (hereinafter referred to as TiCN) layer, a carbon oxide (hereinafter referred to as TiCO) layer, and a carbon oxynitride (hereinafter referred to as TiCNO) layer. (Hereafter, TiC
(Indicated by NO)), one or more of the layers, (b)
Aluminum oxide also having a granular crystal structure (hereinafter, referred to as
Al ₂ O ₃ ) layer, (c) Ti carbonitride (hereinafter referred to as 1-TiCN) layer having a vertically-grown crystal structure, and above (a), (b) and (c) In addition, the thickness of the coating cermet is such that the Ti carbon / nitride / oxide layer is relatively thin, while the Al ₂ O ₃ layer and the 1-TiCN layer are relatively thick. Tools are also known, and it is well known that they are used for continuous cutting and interrupted cutting of various steels and cast irons.

Further, as the Al ₂ O ₃ layer constituting the hard coating layer of the above-mentioned conventional coated cermet tool, those having an α-type crystal structure and those having a κ-type crystal structure are widely put into practical use. The above l- which also forms the hard coating layer
As described in, for example, JP-A-6-8010 and JP-A-7-328808, the TiCN layer uses a mixed gas containing an organic carbonitride as a reaction gas in a normal chemical vapor deposition apparatus, It is also known that the layer is formed by chemical vapor deposition at a medium temperature range of 700 to 950 ° C. and has excellent toughness itself.

[0005]

On the other hand, cutting in recent years
Need to save labor and energy and reduce costs.
There is a strong demand, and with this, the cutting process tends to be faster
However, in the conventional coated cermet tool described above,
When used for cutting under normal conditions such as steel and cast iron
Is not a problem, but it is particularly viscous and high
High speed of difficult-to-cut materials such as stainless steel and mild steel that show cutting resistance
When used for cutting, this cutting involves significant heat generation.
Therefore, even if the thickness of the hard coating layer is increased, the heat resistance is low.
Cracked Al _TwoO_ThreeThere is no problem in the layer, but especially thicker
On the other hand, heat is applied to the l-TiCN layer with poor heat resistance.
Plastic deformation tends to occur, which causes uneven cutting surface
Wear which results in a relatively short service life.
Is the current situation.

[0006]

Means for Solving the Problems Accordingly, the present inventors have
In view of the above, we will develop a coated cermet tool that does not generate uneven wear on the cutting surface even when it is used for high-speed cutting of difficult-to-cut materials such as stainless steel and mild steel with high heat generation. In order to improve the heat-resistant plastic deformation property of the 1-TiCN layer among the hard coating layers of the coated cermet tool, a study was conducted. L-T which is a constituent layer of the layer
When the iCN layer is formed by a normal chemical vapor deposition apparatus, the reaction gas is mixed with vanadium tetrachloride under the condition that, for example, specifically, the reaction gas composition is TiCl
_{4: 0.5~5%, VCl 4:} 0.01~0.5%, CH
_{3 CN: 0.05~1%, Ar:} 5~40%, N 2: 3~
When the layer is formed under the conditions of 45%, H ₂ : remaining, and the reaction atmosphere temperature: 800 to 950 ° C., and the reaction atmosphere pressure: 4 to 60 kPa, the above-mentioned 1-TiCN layer contains the V component. A composite carbonitride layer of Ti and V is formed.

(B) The composite carbonitride layer of Ti and V obtained in the above (a) retains a vertically-grown crystal structure in the same manner as the l-TiCN layer, and therefore has excellent toughness. Assuming that the content of the V component is 1 to 30 atomic% in the total amount with the Ti component, the resulting composite carbonitride of Ti and V having a vertically elongated crystal structure [hereinafter, l
-(Ti, V) CN] layer has remarkably improved heat resistance due to the inclusion of the V component, and has excellent heat-resistant plastic deformability.

(C) A coated cermet tool in which the above l- (Ti, V) CN layer is applied as a constituent layer of a hard coating layer is used for high-speed cutting of difficult-to-cut materials such as stainless steel and mild steel with high heat generation. Even when the l- (Ti, V) CN layer is used in a thickened state, the l- (Ti, V) CN layer itself has excellent heat-resistant plastic deformation properties as described above, and is also hard. The Al ₂ O ₃ layer constituting the coating layer is also excellent in heat plastic deformation, while the TiC · N · O layer does not have sufficient heat plastic deformation, but the l- (Ti, V) CN
Since the thickness of the hard coating layer is relatively small compared to the Al ₂ O ₃ layer and the Al ₂ O ₃ layer, it hardly affects the thermoplastic deformation of the hard coating layer. The cutting surface must exhibit excellent cutting performance over a long period of time while maintaining normal wear. (A) ~
The research result shown in (c) was obtained.

The present invention has been made based on the results of the above research, and is based on a WC-based cemented carbide substrate or TiC
On the surface of a cermet substrate composed of an N-based cermet substrate,
In a coated cermet tool obtained by chemical vapor deposition and / or physical vapor deposition of a hard coating layer with an average layer thickness of 5 to 30 μm, the hard coating layer may be formed by (a) a TiC layer, a TiN layer, a T
T composed of an iCN layer, a TiCO layer, and a TiCNO layer
one or more of iC / NO layers, (b) A
l ₂ O ₃ layer, (c) a ratio of V to Ti with respect to the total amount of 1 to 1
A coated cermet tool comprising a 1- (Ti, V) CN layer containing 30 atomic% and having a hard coating layer having excellent heat-resistant plastic deformation properties, comprising the above (a), (b) and (c). It is characterized by the following.

In the coated cermet tool according to the present invention, the V content of the l- (Ti, V) CN layer constituting the hard coating layer is 1 to 1 in the total amount with the Ti component.
The reason why 30 atomic% is set is that if the ratio is less than 1 atomic%, V
The desired improvement effect on the thermal plastic deformability provided by the components cannot be obtained, while when the proportion exceeds 30 atomic%, the excellent toughness provided by the vertically grown crystal structure tends to decrease. It is desirable that the content ratio be 3 to 15 atomic%. The reason why the average thickness of the hard coating layer is set to 5 to 30 μm is that if the layer thickness is 5 μm, the desired excellent wear resistance cannot be secured. This is because chipping and chipping easily occur in the blade.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated cermet tool of the present invention will be specifically described with reference to examples. WC powder having an average particle diameter of 1 to 3 μm,
TiC powder, ZrC powder, VC powder, TaC powder, Nb
A C powder, a Cr ₃ C ₂ powder, a TiN powder, a TaN powder, and a Co powder were prepared, and these raw material powders were blended in the composition shown in Table 1, wet-mixed in a ball mill for 72 hours, and dried. It is pressed into a green compact at a pressure of 120 MPa, and the green compact is pressed in a vacuum of 6 Pa at a temperature of 1410.
C. for 1 hour under vacuum, and after sintering, the cutting edge is subjected to a honing process of R: 0.05 mm to have a chip shape of ISO standard CNMG120408, and W
Cermet substrates A1 to A8 composed of a C-base cemented carbide were formed.

In addition, as raw material powders,
TiCN having an average particle size of 2 μm (TiC /
(TiN = 50/50) powder, Mo ₂ C powder, ZrC powder, NbC powder, TaC powder, WC powder, Co powder, and Ni powder were prepared, and these raw material powders were blended into the composition shown in Table 2. After being wet-mixed in a ball mill for 24 hours, dried and pressed into a green compact at a pressure of 100 MPa, the green compact was fired in a nitrogen atmosphere of 1.3 kPa at a temperature of 1500 ° C. for 1 hour. After sintering and sintering,
The cutting edge portion was subjected to a honing process of R: 0.03 mm to form cermet bases B1 to B6 having a chip shape of ISO standard CNMG120412 and made of a TiCN-based cermet.

Then, these cermet substrates A-1 to A-1
On the surfaces of A-8 and B-1 to B-6, using a general chemical vapor deposition apparatus, under conditions shown in Tables 3 and 4, TiC.
N · O layer and Al ₂ O ₃ layer, and furthermore l- (Ti, V) C
Table 5 shows the hard coating layer composed of the N layer or the 1-TiCN layer.
The coated cermet tools 1 to 14 of the present invention and the conventional coated cermet tools 1 to 14 were produced by forming the target layer thicknesses and combinations shown in FIG.

The resulting coated cermet tool 1 of the present invention
When the content ratio of the V component in the 1- (Ti, V) CN layer constituting the hard coating layer of No. 14 was measured using an Auger spectrometer, the content ratio was substantially the same as the target content ratio. The thicknesses of the constituent layers of the hard coating layers of the coated cermet tools 1 to 14 of the present invention and the conventional coated cermet tools 1 to 14 were respectively measured in cross section by using a scanning electron microscope. The same average layer thickness (average value of five points measurement) was shown.

Next, the coated cermet tool 1 of the present invention will be described.
-14, and the conventional coated cermet tools 1-14, which were screwed to the tip of a tool steel tool with a fixing jig. Work material: JIS SUS304 round bar, Cutting speed: 220 m / min , Depth of cut: 2 mm, feed: 0.25 mm / rev, cutting time: 10 minutes, dry high-speed continuous turning test of stainless steel under the following conditions: Work material: JIS S15C round bar, Cutting speed: 450 m / min , Depth of cut: 2 mm, feed: 0.25 mm / rev, cutting time: 10 minutes, dry high-speed continuous turning test of mild steel under the following conditions: Work material: JIS SUS304, four longitudinally equally spaced lengthwise Grooved round bar, Cutting speed: 200m / min, Depth of cut: 2mm, Feed: 0.2mm / rev, Cutting time: 5 minutes, Dry high-speed intermittent turning of stainless steel Machining test, Work material: JIS S15C, lengthwise round bar with four equally spaced longitudinal grooves, Cutting speed: 300 m / min, Cutting depth: 1.5 mm, Feed: 0.5 mm / rev, Cutting time: 5 minutes A dry high-speed intermittent turning test of mild steel was performed under the following conditions, and the maximum flank wear width of the cutting edge was measured in each turning test. Table 7 shows the measurement results.

[0016]

[Table 1]

[0017]

[Table 2]

[0018]

[Table 3]

[0019]

[Table 4]

[0020]

[Table 5]

[0021]

[Table 6]

[0022]

[Table 7]

[0023]

From the results shown in Tables 5 to 7, it can be seen that 1-Ti
The coated cermet tools 1 to 14 of the present invention in which the l- (Ti, V) CN layer is a constituent layer of the hard coating layer instead of the CN layer, the l- (Ti, V) CN layer has excellent heat resistance. Due to its plastic deformability, even when cutting stainless steel or mild steel at high speed with high heat generation, plastic deformation of the hard coating layer is suppressed, and as a result, the wear of the cutting edge becomes normal wear, and it is excellent. In contrast, the conventional coated cermet tools 1 to 14 having the l-TiCN layer as a constituent layer, while the l-TiCN layer is plastically deformed due to high heat generated during cutting. It is evident that uneven wear occurs at the cutting edge, which significantly accelerates the progress of wear. As described above, the coated cermet tool of the present invention is excellent not only in cutting under various conditions such as steel and cast iron but also in high-speed cutting of difficult-to-cut materials such as stainless steel and mild steel. Since it exhibits high performance and shows versatile cutting performance, it can sufficiently cope with labor saving and energy saving of the cutting process, and further, cost reduction.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (Reference) C22C 29/02 C22C 29/02 A 29/04 29/04 AZ 29/08 29/08 29/10 29 / 10 29/12 29/12 Z 29/16 29/16 H C23C 14/06 C23C 14/06 P 16/30 16/30 F term (reference) 3C046 FF03 FF05 FF10 FF13 FF16 FF19 FF22 FF25 4K018 AD03 AD04 AD06 FA24 KA15 4K029 AA04 BA44 BA54 BA55 BA60 BB02 BB07 BC02 BD05 EA01 4K030 BA18 BA19 BA35 BA36 BA38 BA41 BA43 BB01 CA03 LA01 LA22

Claims (1)

[Claims] 1. A surface obtained by chemical vapor deposition and / or physical vapor deposition of a hard coating layer with an average thickness of 5 to 30 μm on the surface of a cermet substrate comprising a tungsten carbide-based cemented carbide substrate or a titanium carbonitride-based cermet substrate. In the coated cermet cutting tool, the hard coating layer comprises: (a) a carbide layer, a nitride layer, a carbonitride layer, a carbonitride layer, and a carbonitride layer of Ti, each having a granular crystal structure. (B) an aluminum oxide layer also having a granular crystal structure, (c) a vertically elongated crystal structure, and V being the total amount of Ti A hard coating layer having excellent heat resistance, characterized by comprising a composite carbonitride layer of Ti and V containing 1 to 30 atomic% in proportion to the above, and the above (a), (b) and (c). Exhibits plastic deformation Surface coated cermet cutting tool.