JPH05337704A - Inclined hard layer coating cemented carbide cutting tool - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a cutting tool made of a cemented carbide with a gradient hard layer showing excellent cutting performance for any cutting such as a tip, a drill and an end mill coated with a gradient hard layer. [Structure] The surface of a cemented carbide substrate or the surface of a cemented carbide substrate is further coated with a titanium nitride layer, and a Ti (CxNy) [where x + y = 1] gradient hard layer is coated on the titanium nitride layer. In the cutting tool, the Ti (Cx
Ny) [however, x + y = 1] x in the gradient hard layer
Is substantially 0 on the surface of the cemented carbide substrate or on the surface in contact with the titanium nitride layer, and changes so as to increase in the layer thickness direction from the inner surface to the outer surface, and is substantially 1 on the surface in contact with the titanium carbide layer. On the other hand, y is substantially 1 on the surface of the cemented carbide substrate or the surface in contact with the titanium nitride layer, and changes so as to decrease in the layer thickness direction from the inner surface to the outer surface, and is substantially the outermost surface. A cutting tool made of cemented carbide coated with a graded hard layer that is 0.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting tool made of cemented carbide coated with a gradient hard layer, which exhibits excellent cutting performance for any cutting such as chips, drills and end mills coated with a gradient hard layer. is there.

[0002]

2. Description of the Related Art Generally, as a binder phase forming component, one or more iron group metals are contained, and if necessary, carbides or nitrides of 4a, 5a, and 6a group metals of the periodic table. The surface of a cemented carbide substrate (hereinafter referred to as cemented carbide substrate) containing 0.5 to 30% by weight of carbonitride and the balance of tungsten carbide (hereinafter referred to as WC) and inevitable impurities, Ti, A hard layer-coated cemented carbide cutting tool coated with the compound layer of is known.

As the hard layer of these hard layer-coated cemented carbide cutting tools, TiN layer, TiC layer, TiCN layer, etc. are generally known, but in recent years, C and N are concentrated as shown in FIG. A varying TiCN graded hard layer has been proposed (see JP-A-3-82748).

[0004]

However, the above-mentioned conventional T
The hard layer coated cemented carbide cutting tool coated with iCN graded hard layer does not have sufficient wear resistance when used for high feed continuous cutting, intermittent cutting such as milling, and the TiCN graded hard layer peels off. However, a defect occurs from that portion, and a satisfactory service life is not obtained.

[0005]

Therefore, the present inventors have
As a result of conducting research to solve the above problems and obtain a hard-layer-coated cemented carbide cutting tool that exhibits even longer life when used for intermittent cutting such as high-feed continuous cutting and milling cutting. , (A) When the graded hard layer coated on the surface of the cemented carbide substrate is expressed by Ti (CxNy) [where x + y = 1], x in Ti (CxNy) [where x + y = 1] is the innermost surface. Gradient hard layer that becomes substantially 0, changes so as to increase continuously from the innermost surface to the outermost surface, and changes so as to decrease y continuously, and y becomes substantially 0 on the outermost surface. The cemented carbide cutting tool coated with is more excellent in peeling resistance and longer in service life than conventional ones. (B) In this case, the Ti (CxNy) [where x + y = 1] gradient hard layer and cemented carbide are used. By interposing a TiN layer between the surfaces of the alloy substrate Substantially the same effect can be obtained, it was obtained a finding such.

The present invention has been made on the basis of such findings. (1) Cutting comprising a cemented carbide substrate surface coated with a Ti (CxNy) [where x + y = 1] gradient hard layer. In the tool, the Ti (CxNy) [where x + y = 1]
X in the graded hard layer becomes substantially 0 at the innermost surface in contact with the surface of the cemented carbide substrate, changes so as to increase in the layer thickness direction from the inner surface to the outer surface, and becomes substantially 1 at the outermost surface. , Y is substantially 1 on the innermost surface in contact with the surface of the cemented carbide substrate, changes so as to decrease in the layer thickness direction from the inner surface to the outer surface, and becomes 0 on the outermost surface. Cemented carbide cutting tool. (2) A cutting tool obtained by coating the surface of a cemented carbide substrate with a titanium nitride layer, and coating the titanium nitride layer with a Ti (CxNy) [where x + y = 1] gradient hard layer. (CxNy) [where x + y = 1]
X in the graded hard layer is substantially 0 on the innermost surface in contact with the titanium nitride layer, changes so as to increase in the layer thickness direction from the inner surface to the outer surface, and is substantially 1 on the outermost surface, while y is , A cutting tool made of a gradient hard layer coated cemented carbide, which becomes substantially 1 on the surface in contact with the titanium nitride layer, changes so as to decrease in the layer thickness direction from the inner surface to the outer surface, and becomes substantially 0 on the outermost surface. , Is characterized by.

A physical vapor deposition apparatus such as an ion plating apparatus is used to form the gradient hard layer in the cutting tool made of a cemented carbide coated with a gradient hard layer of the present invention. The reaction gas introduced into the physical vapor deposition apparatus was initially nitrogen gas: 100
%, Hydrocarbon gas: introduced at 0%, and this mixed gas continuously decreases the amount of nitrogen gas introduced as the physical vapor deposition progresses, as shown in the graph of FIG. The hydrocarbon gas is supplied so as to continuously increase in inverse proportion to this, and finally nitrogen gas: 0%,
Hydrocarbon gas: Introduced so as to be 100%. In the graph of FIG. 1, the nitrogen gas introduction amount and the hydrocarbon gas introduction amount are linearly and continuously changed, but the present invention is not limited to this, and may be continuously changed in a curved line.

The graded hard layer thus obtained is made of Ti
(CxNy) [where x + y = 1], the values of x and y are in the range of 0 ≦ x ≦ 1 and 0 ≦ y ≦ 1, and the concentration gradient of C and N in the graded hard layer is obtained. Becomes almost as shown in the graph of FIG. The innermost surface in contact with the cemented carbide substrate or the surface in contact with the titanium nitride layer is x = 0, y
= 1 and substantially TiN, so that the adhesion to the cemented carbide substrate is excellent, while the outermost surface that is directly affected during cutting becomes x = 1 and y = 0 and becomes substantially TiC. Therefore, the wear resistance is excellent, and therefore T
i (CxNy) [where x + y = 1] By coating an inclined hard layer, it is possible to obtain a hard layer-coated cemented carbide cutting tool having excellent properties having both adhesion and wear resistance. Become.

Further, as shown in the graph of FIG. 3, the surface of the cemented carbide substrate is coated with a titanium nitride layer, and the Ti (CxNy) [where x + y =
1] A graded hard layer may be coated. The Ti (CxN
y) [however, x + y = 1] The thickness of the gradient hard layer is 30
It is preferably μm or less. If it exceeds 30 μm, the difference in thermal expansion between the base material and the base material during cutting becomes large, and cracks are likely to occur, resulting in easy peeling. On the other hand, the gradient hard layer is 0.5
If the thickness is less than μm, the effect of suppressing hard layer peeling is insufficient, so the thickness is preferably 0.5 μm or more.

Ti (CxNy) of the present invention [where x
+ Y = 1] In the graded hard layer, as shown in the graphs of FIGS. 2 and 3, x = 0, y = 1 on the innermost surface in contact with the cemented carbide substrate or the surface in contact with the titanium nitride layer, and the outermost surface is x = 1 and y = 0, and the values of x and y are 0 ≦ x ≦ 1.
And a gradient hard layer having a value within the range of 0 ≦ y ≦ 1, the conventional gradient hard layer shown in the graph of FIG.
x and y in i (CxNy) [where x + y = 1] have values in the range of 0 <x <1 and 0 <y <1, and the gradient hard layer coating is different due to the difference in the gradient hard layer. The cutting effect of the cemented carbide cutting tool is remarkably excellent.

[0011]

EXAMPLES Next, the cutting tool made of cemented carbide coated with a graded hard layer of the present invention will be specifically described based on Examples.

Example 1 Co powder, TiC powder, TaC powder, and WC powder each having an average particle size of 3 μm were prepared as raw material powders, and these powders were used as Co powder: 9% by weight, TiC powder: 1% by weight, TaC powder: 2% by weight, the rest: WC powder was mixed and mixed, then molded into a green compact, and the green compact was sintered under normal conditions to produce a sintered body. The sintered body was ground to produce a WC-based cemented carbide chip having a shape of ISO standard TNGA160408.

Next, this WC-based cemented carbide tip is mounted in the upper part of a normal ion plating apparatus, while Ti is placed in the lower part of the ion plating apparatus.
Filled with metal. In such a state, the inside of the ion plating apparatus was kept in a vacuum of 1 × 10 ⁻⁵ Torr, and the temperature rising rate was 6 ° C./min. To 700 ° C, and then
While maintaining this temperature, the atmosphere was maintained in an Ar gas atmosphere of 5 × 10 ^-2 Torr for bombard cleaning.

Further, the Ti metal is heated and evaporated by energization and the like, and only nitrogen gas is supplied from the supply port, the supply of nitrogen gas is immediately reduced, acetylene gas is introduced, and ion plating is performed while discharging from the discharge port. The pressure inside the apparatus was maintained at 1.0 × 10 ⁻³ Torr, and physical vapor deposition was performed while continuously changing the mixing ratio of nitrogen gas and acetylene gas in inverse proportion to each other. On the surface, the innermost surface becomes x = 0, y = 1 and becomes substantially TiN, and the outermost surface becomes x = 1, y = 0 and becomes substantially TiC. Thickness: Ti (CxN) of 4.0 μm
y) [however, x + y = 1] The gradient coated chip 1 of the present invention coated with the gradient hard layer was produced.

Further, only about 10 nitrogen gas is supplied from the supply port.
A TiN layer having a thickness of 0.5 μm is formed on the surface of the WC-based cemented carbide chip while being supplied for a period of time, and then the same is formed on the TiN layer formed on the surface of the WC-based cemented carbide chip. Then, the innermost surface becomes x = 0, y = 1 and becomes substantially TiN, and the outermost surface becomes x = 1, y = 0 and becomes substantially TiC. Thickness: 3.5 μm Ti (CxNy) [However, x + y = 1] The gradient coated chip 2 of the present invention coated with the gradient hard layer was produced.

Conventional Example 1 On the other hand, for comparison, the ISO standard T manufactured in Example 1 was used.
A WC-based cemented carbide chip having the shape of NGA160408 was subjected to bombard cleaning in the same manner as in Example 1, and then, from the supply port, nitrogen gas: acetylene gas = 0.
A mixed gas of 1: 0.9 is supplied, and subsequently, the supply amount of nitrogen gas is decreased and at the same time the supply amount of acetylene gas is increased, and finally, nitrogen gas: acetylene gas = 0.
It is supplied so that it becomes a mixed gas of 9: 0.1, and the innermost surface is x = 0.1, y = on the surface of the WC-based cemented carbide chip.
0.9, the outermost surface is x = 0.9, y = 0.1 Thickness: 4.0 μm Ti (CxNy) [where x + y =
1] A conventional hard-coated chip was prepared by coating a graded hard layer.

A continuous cutting test and an interrupted cutting test were carried out on the inclined coated chips 1 and 2 of the present invention and the conventional coated chips under the following conditions, and the results are shown in Table 1. 1 Continuous dry cutting test (1) High speed cutting test Work material: SNCM439 (Brinell hardness: 250), Cutting speed: 210 m / min, Feed: 0.25 mm / rev. , Depth of cut: 1.5 mm, continuous dry cutting, crater wear depth (μm) after 20 minutes of cutting, and flank wear width V of cutting edge
The time (minutes) until B 2 became 0.3 mm was measured, and the measurement results are shown in Table 1.

(2) Medium and low speed cutting test Work material: SNCM439 (Brinell hardness: 250), cutting speed: 150 m / min, feed: 0.25 mm / rev. The depth of cut: 1.5 mm, continuous dry cutting was performed, and the time (minutes) until the flank wear width VB of the cutting edge reached 0.3 mm was measured. The measurement results are shown in Table 1.

2 Intermittent dry cutting test Work material: A cylindrical body made of SCM440 (Brinell hardness: 300) and having four grooves on the outer circumference in the axial direction, cutting speed: 100 m / min, feed: 0.21 mm / rev ． Incision: 1.0 mm, dry cutting was performed, and the number of cutting edges in which a defect occurred out of 10 test cutting edges was measured, and the measurement results are shown in Table 1.

[0020]

[Table 1] From the results shown in Table 1, it can be seen that the gradient coated chips 1 and 2 of the present invention have excellent cutting characteristics as compared with the conventional coated chips.

Example 2 A composition having a composition corresponding to K10 of JIS standard B4104,
A drill having an outer diameter of 10 mm was prepared, the surface of this drill was bombarded cleaned in exactly the same manner as in Example 1, and then only nitrogen gas was supplied from the supply port to immediately reduce the supply of nitrogen gas and to supply acetylene gas. Introduced,
Maintaining the pressure in the ion plating device at 1.0 × 10 ^-3 Torr while discharging from the discharge port, performing physical vapor deposition while continuously changing the mixing ratio of nitrogen gas and acetylene gas in inverse proportion, On the surface of the drill, the innermost surface is x = 0, y = 1 and is substantially TiN, and the outermost surface is x = 1, y = 0 and is substantially TiC.
Ti (CxNy) of 4.0 μm [where x + y = 1]
An inclined coated drill 1 of the present invention coated with an inclined hard layer was produced.

Further, only about 10 nitrogen gas is supplied from the supply port.
Thickness of 0.5 μm on the surface of the drill while supplying for minutes
Of the TiN layer formed on the surface of the drill, and then the innermost surface is x = 0, y =
1 and substantially TiN, and the outermost surface is x = 1, y = 0
Becomes substantially TiC. Thickness: 3.5 μm Ti
(CxNy) [where x + y = 1] The gradient coated drill 2 of the present invention coated with the gradient hard layer was produced.

Conventional Example 2 On the other hand, JIS standard B prepared in Example 2 for comparison.
It has a composition corresponding to K10 of 4104, and outer diameter: 10 m
After carrying out bombard cleaning of the m drill in the same manner as in Example 2, first, a mixed gas of nitrogen gas: acetylene gas = 0.1: 0.9 is supplied from the supply port, and then the supply amount of nitrogen gas is reduced. At the same time, while increasing the supply amount of acetylene gas, finally nitrogen gas: acetylene gas =
It is supplied so as to be a mixed gas of 0.9: 0.1, and the W
On the surface of the C-based cemented carbide drill, the innermost surface is x = 0.1,
y = 0.9 and outermost surface is x = 0.9 and y = 0.1 Thickness: 4.0 μm Ti (CxNy) [where x +
y = 1] A conventional coated drill coated with an inclined hard layer was produced.

A drilling test was conducted on these coated drills of the present invention and conventional coated drills under the following conditions, and the results are shown in Table 2. 3 Drilling test Work material: Thickness: 20 mm thick plate made of SCM440 (Brinell hardness: 220) Cutting speed: 60 m / min, Feed: 0.2 mm / rev. Under the conditions of, 2500 holes are drilled, total cutting length: 50m
Was drilled to measure the wear amount of the margin part of the drill and the wear amount of the blade back part, and the measurement results are shown in Table 2.

[0025]

[Table 2] From the results shown in Table 2, the coated drills 1 and 2 of the present invention
Indicates that the drilling characteristics are superior to the conventional coated drills.

Example 3 The composition is equivalent to JIS M20, and the outer diameter is 6 mm.
Of the end mill prepared in Example 1 on the surface of this end mill.
A TiN layer with a thickness of 0.5 μm was formed in exactly the same manner as, and the supply of nitrogen gas was immediately reduced and acetylene gas was introduced, while discharging the used nitrogen gas and acetylene gas from the outlet. The pressure inside the ion plating device was maintained at 1.0 × 10 ⁻³ Torr, and physical vapor deposition was performed while continuously changing the mixing ratio of nitrogen gas and acetylene gas so as to be in inverse proportion. S: A Ti (CxNy) [however, x + y = 1] gradient hard layer having a thickness of 4.0 μm was coated to prepare a gradient coated end mill 1 of the present invention.

Furthermore, only about 10 nitrogen gas is supplied from the supply port.
The thickness of the surface of the end mill is 0.5 while feeding for 0.5 minutes.
.mu.m TiN layer is formed, and then the innermost surface is x = in the same manner on the TiN layer formed on the surface of the end mill.
0, y = 1 and substantially TiN, and the outermost surface is x =
1, thickness at which y = 0 becomes substantially TiC: 3.5
A gradient coated end mill 2 of the present invention coated with a Ti (CxNy) [where x + y = 1] gradient hard layer of μm was produced.

Conventional Example 3 On the other hand, JIS standard M prepared in Example 3 for comparison.
An end mill having a composition corresponding to 20 and an outer diameter of 6 mm was subjected to bombard cleaning in the same manner as in Example 3,
First, from the supply port, nitrogen gas: acetylene gas = 0.1:
A mixed gas of 0.9 is supplied, and subsequently, the supply amount of nitrogen gas is decreased and at the same time the supply amount of acetylene gas is increased, and finally, nitrogen gas: acetylene gas = 0.9:
It is supplied so as to be a mixed gas of 0.1, and the innermost surface has x = 0.1, y = 0.9 and the outermost surface has x = 0.9, y = 0.1 on the surface of the end mill. Thickness: 4.0 μm Ti (CxNy) [where x + y = 1] A conventional coated end mill coated with a gradient hard layer was prepared.

The coated end mills 1 and 2 of the present invention and the conventional coated end mills were subjected to wet-cutting test of steel by the down-cut method under the following conditions, and the results are shown in Table 3. 4 Wet piece cutting test of steel by down-cut method Work material: S43C, Cutting speed: 60 m / min, Feed per blade: 0.01 mm / rev. The depth of cut: 15 mm, the width of cut: 0.05 mm, a wet one-sided cutting test was performed, and the amount of wear in the margin of the end mill was 0.2 mm or more or the surface roughness (Rmax) of the vertical surface of the work material was The time when the life reached 6.0 μm or more was defined as the life, and the time until reaching the life was measured in units of 5 minutes.

[0030]

[Table 3] From the results shown in Table 3, it can be seen that the coated end mills 1 and 2 of the present invention have a longer cutting life than the conventional coated end mills.

[0031]

From the results shown in Examples 1 to 3 and Conventional Examples 1 to 3, the gradient hard layer-coated cemented carbide cutting tool of the present invention is a conventional gradient hard layer-coated cemented carbide cutting tool. It has superior performance as compared with, and brings an excellent effect in industry.

[Brief description of drawings]

FIG. 1 is a graph schematically showing the amounts of nitrogen gas and hydrocarbon gas introduced into a physical vapor deposition device for producing a cutting tool made of a gradient hard layer-coated cemented carbide according to the present invention.

FIG. 2 is a graph schematically showing concentration gradients of C and N in a Ti (CxNy) [where x + y = 1] graded hard layer in a cutting tool made of a graded hard layer-coated cemented carbide of the present invention.

FIG. 3 is a graph schematically showing concentration gradients of C and N in Ti (CxNy) [where x + y = 1] graded hard layer in the graded hard layer-coated cemented carbide cutting tool of the present invention.

FIG. 4 is a graph schematically showing a concentration gradient of C and N in a Ti (CxNy) [where x + y = 1] graded hard layer in a conventional hard tool coated with a graded hard layer.

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[Procedure amendment]

[Submission date] July 13, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

Further, the Ti metal is heated and evaporated by energization and the like, and only nitrogen gas is supplied from the supply port, the supply of nitrogen gas is immediately reduced, acetylene gas is introduced, and ion plating is performed while discharging from the discharge port. The pressure in the apparatus was maintained at 1.0 × 10 ⁻⁴ Torr, and physical vapor deposition was performed while continuously changing the mixing ratio of nitrogen gas and acetylene gas so as to be in inverse proportion. On the surface, the innermost surface becomes x = 0, y = 1 and becomes substantially TiN, and the outermost surface becomes x = 1, y = 0 and becomes substantially TiC. Thickness: Ti (CxN) of 4.0 μm
y) [however, x + y = 1] The gradient coated chip 1 of the present invention coated with the gradient hard layer was produced.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0025

[Correction method] Change

[Correction content]

[0025]

[Table 2] From the results shown in Table 2, the coated drills 1 and 2 of the present invention
Indicates that the drilling characteristics are superior to the conventional coated drills.

Claims (2)

[Claims] 1. Ti (CxNy) on the surface of a cemented carbide substrate
[However, in a cutting tool formed by coating a gradient hard layer of x + y = 1], Ti in the Ti (CxNy) [where x + y = 1] gradient hard layer is substantially the surface in contact with the surface of the cemented carbide substrate. It becomes 0 and changes so as to increase in the layer thickness direction from the inner surface to the outer surface and becomes substantially 1 at the outermost surface, while y is substantially 1 at the surface in contact with the surface of the cemented carbide substrate.
The cutting tool made of a gradient hard layer coated cemented carbide is characterized in that it changes so as to decrease in the layer thickness direction from the inner surface to the outer surface and becomes substantially 0 at the outermost surface. 2. A cutting tool obtained by coating the surface of a cemented carbide substrate with a titanium nitride layer, and coating the titanium nitride layer with a Ti (CxNy) [where x + y = 1] graded hard layer. In the Ti (CxNy) [where x + y = 1] gradient hard layer, x is substantially 0 on the surface in contact with the titanium nitride layer.
And changes so as to increase in the layer thickness direction from the inner surface to the outer surface and becomes substantially 1 at the outermost surface, while y is
A superposed gradient hard layer coating, which is substantially 1 on the surface in contact with the titanium nitride layer, changes so as to decrease in the layer thickness direction from the inner surface to the outer surface, and becomes substantially 0 on the outermost surface. Hard alloy cutting tool.