JPH10244405A - Cutting tool made of surface-covering cemented carbide with its hard covering layer having excellent abrasion resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting tool made of surface-covering cemented carbide with its hard covering layer having excellent abrasion resistance. SOLUTION: In a cutting tool made of surface-covering cemented carbide comprising a hard covering layer as thin as 10 to 30μm on an average chemically/physically deposited on the surface of cemented carbide, where the hard covering layer is formed out of a TiCN layer having longitudinally growing crystal structure, one kind or more than two kinds out of Ti compound layers composed of a TiC layer, a TiN layer, a TiCN layer, a TiCO layer, a TiNO layer, and of a TiCNO layer, all of which have a granular crystal structure, a (Ti, M) CN layer as thin as 1 to 10μm (where, M represents one kind or more than two kinds out of Cr, W and Mo, and includes a total volume with Ti by atomic percentage of 0.5 to 10) having a longitudinally growing crystal structure, is disposed therein while being adjacent to the upper surface and/or lower surface of the TiN layer having a longitudinally growing crystal structure consisting of the hard covering layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a hard coating layer having excellent wear resistance, and exhibits excellent cutting performance over a long period of time even when continuous cutting or interrupted cutting of steel or cast iron is performed at high speed. The present invention relates to a cutting tool made of a surface-coated cemented carbide (hereinafter, referred to as a coated cemented carbide tool).

[0002]

2. Description of the Related Art Conventionally, generally, for example, JP-A-6-800
No. 8, JP-A-7-328809, etc., a tungsten carbide-based cemented carbide substrate (hereinafter, referred to as
A Ti carbonitride (hereinafter referred to as 1-TiCN) layer having a vertically-grown crystal structure and a Ti carbide (hereinafter referred to as Ti
C) layer, nitride (hereinafter also indicated by TiN)
Layer, carbonitride (hereinafter, shown as TiCN) layer, carbon oxide (hereinafter, shown as TiCO) layer, nitride oxide (hereinafter, TiN)
O) and one or more of the Ti compound layers comprising a carbonitride (hereinafter referred to as TiCNO) layer and also have a granular crystal structure, and have an α-type or a κ.
A hard coating layer composed of an aluminum oxide (hereinafter, referred to as Al ₂ O ₃ ) layer having a crystal structure in which the α-type and the κ-type are mixed together is formed by chemical vapor deposition with an average layer thickness of 10 to 30 μm. Alternatively, coated carbide tools obtained by physical vapor deposition are widely known, and it is also known that the coated carbide tools are used for continuous cutting or interrupted cutting of steel, cast iron, or the like.

[0003]

On the other hand, in recent years, FA and speed of cutting have been remarkable, and there has been a strong demand for labor saving and energy saving of cutting.
It is strongly desired to extend the service life of cutting tools.
In the conventional coated carbide tool described above, the hard coating layer constituting the hard coated layer has good toughness, that is, excellent chipping resistance (a property in which chipping or chipping is unlikely to occur in the cutting edge), but wear resistance is low. At present, the service life is short in a relatively short time because it is not sufficient.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above-mentioned viewpoints, focusing on the hard coating layer of the conventional coated carbide tool, and conducting research to improve the wear resistance of the hard coating layer, the hard coating layer of the conventional coated carbide tool was formed. Adjacent to the upper surface and / or lower surface of the l-TiCN layer to be formed, is a composite carbonitride of Ti and M [hereinafter referred to as l- (Ti, M) CN] layer having the same vertically elongated crystal structure (here, M Represents one or more of Cr, W, and Mo, and is 0.5 to 0.5% of the total amount with Ti.
(Containing 10 atomic%) with an average layer thickness of 1 to 10 μm, in the resulting coated carbide tool, the 1- (Ti, M) CN layer has excellent toughness due to the elongated growth crystal structure. , Having high hardness due to M content,
In combination with the coexistence with the l-TiCN layer having excellent toughness, while the hard coating layer retains excellent fracture resistance,
Since it has excellent wear resistance, it can be cut for a long time without chipping or chipping of the cutting edge even when cutting under normal conditions, as well as continuous cutting and intermittent cutting under high speed conditions. The research results show that they will exhibit excellent cutting performance.

The present invention has been made based on the results of the above-mentioned research, and has disclosed that l-Ti
CN layer, TiC layer, TiN layer, TiCN layer, TiCO
Layer, TiNO layer, and the one or more of Ti compound layer formed of TiCNO layer, chemical vapor deposition and the hard coating layer consisting of the the Al ₂ O ₃ layer with an average layer thickness of 10 to 30 [mu] m / Alternatively, in a coated carbide tool formed by physical vapor deposition, l- (Ti, M) C is formed adjacent to the upper surface and / or lower surface of the l-TiCN layer constituting the hard coating layer.
N layer (where M is one of Cr, W, and Mo)
A hard coating layer having an average thickness of 1 to 10 μm, wherein the hard coating layer has excellent wear resistance. It is characterized by a coated carbide tool having a property.

[0006] In the coated carbide tool of the present invention,
The reason why the average layer thickness of the hard coating layer is set to 10 to 30 μm is that if the layer thickness is less than 10 μm, the desired excellent wear resistance cannot be secured for a long period of time.
If the thickness exceeds μm, the fracture resistance is reduced. The reason why the average layer thickness of the 1- (Ti, M) CN layer is 1 to 10 μm is that if the layer thickness is less than 1 μm, a desired effect of improving wear resistance cannot be secured. This is because if the thickness exceeds 10 μm, chipping (minute chipping) tends to occur on the cutting edge. Furthermore, the M content ratio of the l- (Ti, M) CN layer is set to 0.5 to 10 atomic% because the ratio is 0.1%.
If the content is less than 5 atomic%, the effect of improving the hardness of the layer itself is not sufficient, and as a result, the improvement of the wear resistance of the hard coating layer becomes insufficient, while if the content exceeds 10 atomic%, the toughness of the layer itself tends to decrease. Appear, which causes chipping of the hard coating layer.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated carbide tool of the present invention will be specifically described with reference to examples. As the raw material powder, fine-grained WC powder having an average particle diameter of 1.5 μm;
C powder, 1.2 μm (Ti, W) CN (by weight ratio,
Hereinafter, the same, TiC / TiN / WC = 24/20/56)
Powder (Zr, W) CN (ZrC / Zr)
N / WC = 29/22/49) powder, 1.3 μm (Ta, Nb) C (TaC / NbC = 90/10) powder, 1 μm Cr powder, and 1.2 μm Co powder Then, these raw material powders were blended in the blending composition shown in Table 1, wet-mixed in a ball mill for 72 hours, dried, and then press-molded into a green compact having a shape conforming to ISO / CNMG120408. Carbide substrates A to E were also manufactured by vacuum sintering under the conditions shown in Table 1. Table 1 shows the internal hardness (Rockwell hardness A scale) of each of the carbide substrates A to E.

Next, these super hard substrates A to E are respectively
Finished to the specified shape, and honed.
Table 2 and Table 3 using a normal chemical vapor deposition apparatus
Under the conditions shown in Table 4, the compositions and
And average thickness of the Ti compound layer (l-TiCN layer and l
For the-(Ti, M) CN layer, the symbols in Table 3
Ti-based CN 1 to 10) and Al_TwoO_ThreeLayers (Table 2
And in Table 4, αAl _TwoO_Three, ΚAl_TwoO_Three, And α
+ ΚAl_TwoO_ThreeHave crystal structures of α-type, κ-type, and
And α + κ mixed type Al_TwoO_ThreeThe hard coating consisting of
By forming a cover layer, the coated carbide tools of the present invention 1 to 15
And conventional coated carbide tools 1 to 15 were produced.
In addition, the coated carbide tools 1 to 15 of the present invention obtained as a result were
M of Ti-based CN2-10 in each hard coating layer
Quantitative analysis of the content ratio with an energy dispersive X-ray analyzer
As a result, the value is almost the same as the target M content ratio in Table 3.
showed that.

Next, the above-mentioned coated carbide tools 1 to 1 according to the present invention.
5 and the conventional coated carbide tools 1 to 15, a work material: a round bar of SCM440 (hardness: HB220), a cutting speed: 350 m / min. , Depth of cut: 2 mm, feed: 0.3 mm / rev, wet high-speed continuous cutting test of alloy steel under the following conditions (hereinafter referred to as cutting condition A), and work material: SCM440 (hardness: HB220). Round bar with four longitudinal grooves at equal intervals in the longitudinal direction, Cutting speed: 380 m / min. Infeed: 1.5 mm. , Feed: 0.3 mm / rev, a dry high-speed intermittent cutting test of alloy steel under the following conditions (hereinafter referred to as cutting conditions B), and in any of the cutting tests, the flank wear width of the cutting edge was reduced to 0.3 mm. The cutting time up to was measured. Table 6 shows the measurement results.

[0010]

[Table 1]

[0011]

[Table 2]

[0012]

[Table 3]

[0013]

[Table 4]

[0014]

[Table 5]

[0015]

[Table 6]

[0016]

From the results shown in Tables 4 to 6, all of the coated carbide tools 1 to 15 of the present invention are subjected to severe cutting conditions due to the l- (Ti, M) CN layer constituting the hard coating layer. Even in high-speed continuous cutting and high-speed intermittent cutting of steel, the cutting edge does not have chipping or chipping, shows excellent wear resistance, and enables cutting for a long time. It is clear that in the conventional coated cemented carbide tools 1 to 15 having no (Ti, M) CN layer, the wear progresses quickly and the service life is relatively short. As described above, in the coated carbide tool of the present invention, the hard coating layer constituting the coated hard tool has excellent wear resistance, so that not only continuous cutting or interrupted cutting under ordinary conditions such as steel or cast iron, but also Even in high-speed cutting where even more wear resistance is required, it can exhibit excellent cutting performance over a long period of time, and therefore can sufficiently respond to FA and labor saving in cutting. It is.

Claims (1)

[Claims] 1. A titanium carbonitride layer having a vertically elongated crystal structure, and a Ti carbide layer, a nitride layer, and a carbonitride layer each having a granular crystal structure on a surface of a tungsten carbide-based cemented carbide substrate. , A hard coating layer composed of one or more of Ti compound layers consisting of a carbon oxide layer, a nitrogen oxide layer, and a carbon oxynitride layer, and an aluminum oxide layer also having a granular crystal structure In a surface-coated cemented carbide cutting tool formed by chemical vapor deposition and / or physical vapor deposition with an average layer thickness of 10 to 30 μm, T having a vertically elongated crystal structure constituting the hard coating layer
i adjacent to the upper and / or lower surface of the carbonitride layer,
A composite carbonitride layer of Ti and M also having a vertically elongated crystal structure (where M is one of Cr, W, and Mo)
A hard coating layer characterized by having an average layer thickness of 1 to 10 μm, wherein the hard coating layer represents one or more kinds and contains 0.5 to 10 atomic% in proportion to the total amount with Ti). Surface-coated cemented carbide cutting tool with excellent wear resistance.