JPS6365079A - Surface coated head alloy for cutting tool having high resistance to chipping - Google Patents

Abstract

PURPOSE:To produce a surface coated hard alloy for cutting tools having high resistance to chipping by specifying the compressive residual stress of a hard coating layer consisting of carbide, etc., of group 4a metals at the time of forming said hard coating layer on the surface of a base body consisting of a WC-base sintered hard alloy, etc. CONSTITUTION:The hard coating layer consisting of the single layer of one kind among the groups of the carbide, nitride and oxide of the group 4a metals of the periodic table and the solid solns., of >=2 kinds thereof or plural layers of >=2 kinds thereof is formed on the surface of the base body consisting of any among the WC-base sintered hard alloy, TiCN-base cermet or high speed steel. The formation of the hard coating layer is executed by a cluster in beam method without using an ion plating method to decrease the compressive residual stress in the hard coating layer to <=0.7Pa. The generation of exfoliation in the hard coating layer is thereby prevented and the surface coated hard alloy for cutting tools which exhibits the resistance to chipping and exhibits the excellent wear resistance for a long period of time is obtd.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention has excellent fracture resistance and wear resistance, and particularly when used as a cutting tool, the hard coating layer can be easily peeled off. It relates to a surface-coated hard alloy that exhibits excellent cutting performance.

[Conventional technology]

In general, metals from Group 4a of the Periodic Table of Elements are applied to the surface of a substrate made of tungsten carbide (hereinafter referred to as WE)-based cemented carbide, titanium carbonitride (hereinafter referred to as T1CN)-based cermet, or high-speed steel. carbides, nitrides, and oxides,
and one of the group consisting of two or more of these solid solutions
A surface-coated hard alloy formed by forming a hard coating layer consisting of a single layer of seeds or a multilayer of two or more types by an ion blasting method is used as a cutting tool.

[Problems that the invention attempts to determine]

However, when using the above-mentioned conventional surface-coated hard alloy as a cutting tool for high-load cutting such as high-speed cutting or interrupted cutting, the hard coating layer tends to peel off, and the hard coating layer tends to peel off in a relatively short period of time. Currently, it reaches the end of its useful life.

[Means for solving problems]

Therefore, from the above-mentioned viewpoints, the present inventors conducted research to develop a surface-coated hard alloy with excellent chipping resistance and whose hard coating layer does not peel off. Approximately 0.9 C) for the hard coating layer of the coated hard alloy
The presence of a high compressive residual stress of Pa or more, and the presence of this compressive residual stress makes it easy for the hard coating layer to peel off.

(b) The compressive residual stress in the hard coating layer is Q, 7G
When the pressure is reduced to below Pa, the peeling phenomenon of the hard coating layer is significantly suppressed.

(C) When the hard coating layer is formed using the cluster ion beam method instead of the conventionally used ion blasting method, the resulting compressive residual stress in the hard coating layer is reduced to 0.70 Pa or less. To learn to do things.

The findings shown in (a) to (C) above were obtained.

This invention was made based on the above knowledge, and is based on the cluster ion beam method. , by forming a single layer or a multilayer of two or more of the group consisting of carbides, nitrides, and oxides of Group 4a metals of the Periodic Table of the Elements, and solid solutions of two or more of these. , the compressive residual stress in the hard coating layer is set to 0.7 GPa or less, and the hard coating layer exhibits excellent fracture resistance without peeling even when used for high-speed cutting or interrupted cutting, and has excellent fracture resistance over a long period of time. This is a surface-coated hard alloy for cutting tools that exhibits excellent wear resistance.

Note that the compressive residual stress of the hard coating layer can be easily measured by a well-known X-ray stress measuring method.

〔Example〕

Next, the surface-coated hard alloy of the present invention will be specifically explained using examples.

Example 1 As a substrate, the composition of RSO standard p20 and the same standard 5
Prepare a WCC cemented carbide tip with the shape of NGN 432 (slow 7-way tip), and use this tip as the first
The cluster ion beam device shown schematically in the figure is mounted on the downward facing substrate 1, and the metal 3 charged into the crucible 2 is heated by the heating coil 4 under the conditions shown in Table 1. The evaporated metal is heated to evaporate, and the evaporated metal is reacted while passing through the ionization electrode 5 and the acceleration electrode 6, to form a hard coating layer on the surface of the chip with the composition and average layer thickness also shown in Table 1. Surface-coated hard alloys of the present invention (hereinafter referred to as coated alloys of the present invention) 1 to 7 were manufactured by this method.

For the purpose of comparison, the same substrate was mounted on the ion blating device shown schematically in FIG. Then, the metal 3 in the crucible 2 is heated and evaporated by the electron beam 7 arranged in parallel, and the evaporated metal is reacted while passing through the ionization electrode 5, so that the composition and average layer shown in Table 1 are formed on the chip surface. Conventional surface-coated hard alloys (hereinafter referred to as conventional coated alloys) 1 to 7 were each manufactured by forming a thick hard coating layer.

Next, for the various coating alloys obtained as a result, the compressive residual stress of the hard coating layer was measured using X-rays.
Cutting speed: 130m/rev, feed = 0.5mm/rev, depth of cut: 1.5mm.

Continuous cutting test of steel under the conditions of cutting time: 20+m, and work material: SN
CM 439 (hardness: HB270), cutting speed 21o
An interrupted cutting test was conducted on steel under the following conditions: 0.3 mx/rev, feed: 0.3 mx/rev, depth of cut: 2 m, cutting time: 3 m, and in the former continuous cutting test, the flank wear width of the cutting edge was At the same time as measuring, the condition of the hard coating layer was also observed, and in the latter interrupted cutting test, 1
The number of chipped cutting edges out of the number of 0 test cutting edges was measured.

These results are shown in Table 1.

Example 2 The base is made of T1CN-based cermet and has an SMM shape.
C) Except using a 432 throw-away tip.
In the same manner as in Example 1, the coating alloy 8 of the present invention and the conventional coating alloy 8 were manufactured under the conditions shown in Table 1, respectively.

Regarding these coating alloys, the compressive residual stress of the hard coating layer was measured using X-rays, and the workpiece material: 80M41
5 (hardness: HB150), cutting speed: 2007Fl
/mia.

Feed: 0.36 all/rev, depth of cut 20
．． Continuous cutting test of steel under the conditions of 5 approval, cutting time: 20 mIL, and work material: SN
CM 439 (hardness: HB250), cutting speed: 15
An interrupted cutting test was conducted on steel under the following conditions: 0 m/speed, feed rate of 20, 25 M/rev, depth of cut of 22, and cutting time of 3 mm. As in Example 1, in the former continuous cutting test, In addition to measuring the flank wear width of the cutting edge, the condition of the hard coating layer was observed, and in the latter intermittent cutting test, the number of defects among 10 tested cutting edges was measured. These results are shown in Table 1.

Example 3 Example 1 except that a two-sided end mill made of high-speed steel and having a diameter of 6 mm x length of 50 m was used as the base.
Coated alloy 9 of the present invention and conventional coated alloy 9 were manufactured under the conditions shown in Table 1 in the same manner as in Table 1.

Similarly, for the resulting coated alloy, the compressive residual stress of the hard coating layer was measured, and the workpiece material: 5KD-
61 (Hardness: HRC34), Cutting speed: 25m/hide, Feed: o, o15mx/blade, Depth of cut: S HXX width Cutting oil: Oil-based, A side cutting test on steel was conducted under the following conditions. The cutting length until the second outer circumference wear of the blade reached 0.3 rnx was measured, and the state of the hard coating was observed. These results are shown in Table 1.

〔Effect of the invention〕

From the results shown in Table 1, the coated alloys 1 to 9 of the present invention are:
All of them exhibit excellent wear resistance and chipping resistance, but in conventional coating alloys 1 to 9, the compressive residual stress in the hard coating layer is as high as about 0.7 GPa or more, so the hard coating layer It is clear that peeling occurs, chipping resistance is low, and relatively poor wear resistance is exhibited.

As mentioned above, the surface-coated hard alloy of the present invention has extremely low compressive residual stress of 0.7 () Pa or less in the hard coating layer, so it can be used as a cutting tool for high-feed cutting, interrupted cutting, etc. In some cases, the hard coating layer exhibits excellent chipping resistance without peeling, and the hard coating layer has excellent wear resistance, and exhibits excellent cutting performance over an extremely long period of time. It is.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing an ion brating device,
FIG. 2 is a schematic explanatory diagram showing a cluster ion beam device. 1... Substrate, 2... Crucible, 3...
Metal, 4... Heating coil, 5... Ionization electrode, 6... Accelerating electrode, 7... Electron beam.

Claims (2)

[Claims] (1) A carbide of a group 4a metal of the periodic table of elements,
In a surface-coated hard alloy formed by forming a hard coating layer consisting of a single layer or a multilayer of two or more of nitrides, oxides, and solid solutions of two or more of these, the above-mentioned The compressive residual stress of the hard coating layer is 0.7 GPa.
A surface-coated hard alloy for cutting tools with excellent fracture resistance, characterized by the following: (2) A surface-coated hard alloy for a cutting tool having excellent fracture resistance as set forth in claim (1), wherein the hard coating layer is formed by a cluster ion beam method.