JPH0397866A - Coated cemented carbide tool - Google Patents

Abstract

PURPOSE:To manufacture a coated cemented carbide tool improved in wear resistance by using a sintered body composed of the specific composition of WC base cemented carbide and specified with carbon containing condition and saturation magnetic flux density in the finish sintered body as a base body and forming the coated tool. CONSTITUTION:The sintered body of the WC base cemented carbide composed of one or more kinds among carbide, nitride and carbide-nitride of IV A, V A and VI A groups in the periodic table and one or more kinds in Fe group and Cr group, and in which the content of carbon is in the low carbon range of two phase range, and having <=(14-16) gauss per Co 1% the saturation magnetic flux density, is used as the base body. On the base body, inner layer of titanium carbide-nitride having 0.5-10mu thickness is formed with CVD process using organic CN compound as reaction gas and further, outer layer composed of one or more layers of aluminum oxide, titanium carbide-nitride and/or titanium nitride having 0.5-10mu thickness is formed with the CVD process. By this method, the coated tool being available to high speed continuous cutting field, is obtd.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to improvements in coated cemented carbide tools.

Specifically, the present invention relates to expanding the range of applications of M-covered cemented carbide tools with improved high-speed cutting performance.

[Conventional technology]

The hard phase is WC-Co, WC-(WT i T
a) TiC. A
Multilayer coated tools made of various combinations of l 20 3, TiCN, TiN, etc. have a wide range of applications and are in practical use as long-life cutting ΔIJL tools.

The CVD method and the PVD method are mainly used as the manufacturing method, but various coating methods are also being used due to advances in process technology.

In addition, alloys in which a small amount of TiN is added to JIS M cemented carbide are widely used for the substrate, and by adding nitrogen, surface modification such as removal of β layer can be achieved, and toughness is further improved. Conventionally, T i C was used for wear-resistant positioning applications using the CVD method.
, A]. For applications where multi-layer coatings such as 203 are used and fracture resistance is important, T
A tool coated with iN is applied.

[Problems to be solved by the invention] As mentioned above, for conventional uses that emphasize chuma, 'l゛IC,
A. 1 20 3 etc. is applied to the surface to coat the surface with a highly wear-resistant film 11), which is effective, but on the other hand, due to the fragile decarburized layer that forms at the interface between the substrate and the film during formation, chipping resistance is reduced. It has the disadvantage of being weak in
Attempts are being made to improve its strength by adding too much carbon into the base or enriching it near the surface. However, since the constant presence of carbon in the base body reduces the plastic deformability and wear resistance of the base body, it is preferable that the carbon content be as low as possible.

"T. Stage to Solve the Problems" Therefore, the present inventors have proposed the following: J. Is it possible to suppress the decarburized layer that occurs at the interface of the skin-like substrate in an alloy with a low carbon content that does not produce foreign phases in ISM cemented carbide?4 As a result of studying the CVD method, we found that it would be better to use a gas that makes the normal CVD method lower in temperature and more reactive.

Further, when nitride is added to this substrate, the effect is further enhanced. The nitride may be a 4a or 5a group condensate or carbonitride. Depending on the use and purpose, for example, NbN, TiN, etc. are excellent for high-speed continuous cutting, etc., and for applications that require intermittent cutting. , the purpose is T a N, Z r N,
H f N and the like tend to be superior, and similar effects can be obtained even when a plurality of nitrides and carbonitrides are used.

[Operation] As described above, the present invention has a period {1 a of 4a, 5a, 6
The base material is a WC-based cemented carbide made of one or more of group A carbides, nitrides, and carbonitrides and one or more of Fe group and Cr group, and the carbon content in the final sintered body is two-phase. It is a low carbon region in the region, and the saturated density is 14 per Col%.
The base is a sintered body with a temperature of ~16 gauss or more, and the inner layer is coated with titanium carbonitride of 0.5-10 microns by the CVD method using an organic CN compound as a reaction gas, and further coated with titanium carbonitride of 0.5-10 microns. Aluminum oxide, titanium carbonitride and/or titanium nitride t If4 by CVD method
and/or a coated cemented carbide tool characterized by being coated with multiple layers.

The substrate and membrane of the coated tool according to the invention are limited for the following reasons.

1) Carbon saturation magnetic flux density in i & final sintered body is 14 to 16 gauss per Col%
(Low carbon region in 2 phases) Carbon content F in combustion method
Since the r value has a large error term, the saturation magnetic flux density commonly used for cemented carbide was used. The reason for using the saturation magnetic flux density is that carbon measurement in the low carbon region, which is the subject of this invention, can be carried out with the highest degree of stability.

p8 Japanese magnetic density is 14 g a LJ per Cal%
SS. If less than 4S, carbon is insufficient and foreign phases are likely to occur, and if it exceeds +6) ζa USS, grain growth tends to occur and is unsuitable for high-speed cutting.
4 to j6 gauss.

2) Inner layer 0. CVD method using 5-10 micron organic CN compound If the inner layer of titanium carbonitride is less than 0.5 micron, it is not effective in suppressing C migration, and if the inner layer is less than 10 micron, In order to significantly inhibit toughness, the thickness was set to 0.5 to 10 microns.

3) Outer layer 0.5 to 10 microns CVD method If the single layer and/or multilayer outer layer of aluminum oxide, titanium carbonitride, and titanium nitride is less than 0.5 microns, sufficient abrasion resistance cannot be imparted. If it exceeds 1 layer, 2
Since it would become too thick and brittle, it was set to 0.5 to 10 microns.

The present invention will be specifically explained below.

[Example 1] Commercially available WC powder (average particle size 5.0 μm), 1”jC powder (average particle size 1.0 μm), TiN powder (average particle size 1.0 μm),
Using TaC powder (1.5, um) and Co powder for bonding, JIf for turning is used for turning: equivalent to JIS M20 used for bodies (II! Residual WC-2TiC
-5TaC-7Co-0.3TiN). The carbon content was adjusted by adding W. These powders were blended, mixed, dried, pressed, and sintered in air at 1.100°C for 1 hour to prepare transverse rupture strength test pieces. The saturation magnetic flux density, hardness, and fracture toughness values of the test piece were 7! N was determined. The results are shown in Table 1.

In sample number 8.9 in Table 1, the fracture toughness value was extremely low due to the decarburized phase.

SNMA from this alloy 4. 3 Added a chip with the shape of 2. In addition, this chip was placed in a CVD reactor, and the temperature was raised to so ``c'' while flowing H gas.Tj.CI4 2%, C from 800℃
Ill it a mixed gas consisting of H, CN2%, HJ4
7 if / min pressure 4 0 mm H
Tj
A 2 micron coating of CN was applied.

The chip was further heated to 100° C., and the gas mixture was changed to a mixture of 1.2% TiCl and 2% N, and the mixture was reacted for 6 hours to form 6 microns of TjN on the substrate. Next, a mixed gas consisting of Co2 2% AIC"13 2% H2 remainder was mixed at a flow rate of 7'1K/min and a pressure of 4.
A ]. 203 was coated with 2 microns.

A cutting test was conducted on this chip using a commercially available TtC6 micron-A12032 micron chip under UF conditions.

The cutting test conditions are longitudinal continuous steel bar for horizontal forming LηiTI1
It was carried out at Since the load is continuous in longitudinal continuous cutting,
Plastic deformation resistance, which is important for cutting performance, was confirmed.

Cutting speed 200m/mjn Feed 0. 2mrn/rev cutting depth 3.
Ornm Cutting time 2 min 30 min The results are shown in Table 2.

Table 2 sample number 8. 9 was not tested due to the decarburization phase, but the chip of the present invention showed normal wear with a decrease in plastic deformation as the amount of carbon decreased, whereas the commercially available chip had large plastic deformation. , abnormal wear has occurred on the nose. Furthermore, in order to compare the wear resistance, it was found that there was no significant difference between the chips even when the cutting time was 30 minutes, but the maximum amount of wear on the flank surface after 30 minutes of cutting was different in the slope of the constant wear between the inventive chip and the commercially available chip, and there was a large difference. .

[Example 2] Commercially available WC powder (average particle size 5.0 μm) Ta
JIs KI used for turning substrate in 11 using C powder (1.5 μm) and Co powder as binder phase
O equivalent (composition remaining W C-3 T a C-f
3Co). Carbon was adjusted by adding W or carbon. These powders were blended, and after the mixing was completed, they were dried and press-molded.
After 1hr sintering in vacuum at 1400''C, a transverse rupture strength test piece was produced.The saturation magnetic flux density, hardness, and fracture toughness of the test piece were measured.

The results are shown in Table 3.

Sample No. 18.19 in Table 3 had an extremely low fracture toughness f due to the decarburized phase.

A chip in the shape of SNMA432 was added to this alloy, and this chip was placed in a CVD reactor and H
, The temperature was raised to 800° C. while flowing gas. 800
TIC1.42% from ℃, C H3C N2%, H
Flow a mixed gas consisting of 2 residues t 7 i! I/mi
Supplied under the conditions of n pressure 40 mm Hg 0.5
A 2 micron layer of TiCN was coated onto the substrate by reacting for a period of time.

The temperature of the chip was further raised to 1000°C, and the mixed gas was mixed with TiC1. The composition was changed to 2% N, 2% CH4, and 2% CH4, and a 6R reaction was performed to form 6 microns of TiCN on the substrate. Next, TiC1<2%, N, 2% H2
9* at a flow rate of 7 rl/min and a pressure of 4
Ti is supplied under the condition of 0 mmHg, and Ti
A 2 micron coating of N was applied.

This chip is commercially available TiC6 micron-A 120
A cutting test with a 32 micron chip was conducted under the following conditions.

The conditions for the cutting test were to cut ductile cast iron.

Plastic deformation resistance, which is important for cutting performance, was confirmed.

Cutting speed 250 m/min feed
0. 2mm/rev Depth of cut 3.0mm Cutting time 2min 30min The results are shown in Table 4.

Although there is not much difference from Table 2, the maximum amount of wear on the flank surface after 30 minutes of cutting differs between the inventive chip and the commercially available chip in terms of the slope of steady wear, resulting in a large difference.

〔Effect of the invention〕

The coated cemented carbide tool of the present invention has improved plastic deformation resistance in the base, increased cutting edge strength, and improved wear resistance by specifying the amount of carbon in the base in the final sintered body. This is a tool that has expanded its scope of application to the field of high-speed continuous cutting, which is a feature of coated tools.

Claims (1)

[Claims] The base material is a WC-based cemented carbide consisting of one or more carbides, nitrides, and carbonitrides of groups 4a, 5a, and 6a of the periodic table, and one or more of the Fe group and Cr group, and the final sintered body The base is a sintered body whose carbon content is in the low carbon region of the two-phase region, and the saturation magnetic flux density is 14 to 16 gauss per Col% or less, and an organic CN compound with an inner layer of 0.5 to 10 microns on the base. Coated with titanium carbonitride by CVD method using as a reaction gas, and further coated with 0.5-10 micron CV
A coated cemented carbide tool coated with one layer and/or multiple layers of aluminum oxide, titanium carbonitride and/or titanium nitride by method D.