JP2003048106A - Surface coated cemented carbide throw-away tip having cutting edge part exhibiting superior chipping resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface coated cemented carbide throw-away tip whose cutting edge part exhibits superior chipping resistance. SOLUTION: In this surface coated cemented carbide throw-away tip, on the surface of tungsten carbide base cemented carbide throw-away tip, having a composition such that as a binder phase forming component, 4 to 20 mass % Co and 0.1 to 4 mass % Cr, and the residue is formed by tungsten carbide and inevitable impurities as a hard phase forming component, in which in the measurement by longitudinal section texture observation using an optical microscope, a porous band area where vacancy exists in a ratio of 5 to 30 area % is existent in the cutting face part including a cutting edge ridge line part where the cutting face and flank of the cutting edge part intersect each other extending from the surface to a depth of 20 to 10 μm, and the vacancy ratio of the other body part is 2 area % or less, a composite nitride layer of Ti Al satisfying a composition formula: (Ti1- XAlX)N(wherein at atom ratio, X is 0.15 to 0.65) is physically evaporated as a hard coating layer with an average layer thickness of 1 to 20 μm.

Description

DETAILED DESCRIPTION OF THE INVENTION [0001] TECHNICAL FIELD The present invention relates to various kinds of steels and the like.
Intermittent cutting of cast iron, etc.
When performed under heavy cutting conditions such as high depth of cut or high feed
Ultra-surface coating with excellent cutting resistance
Slow-away tips made of hard alloy (hereafter referred to as coated carbide tips)
It is about). [0002] 2. Description of the Related Art Conventionally, as a coated carbide tip, for example, FIG.
2 is a kind of a physical vapor deposition apparatus schematically shown in FIG.
Tungsten carbide based
A hard alloy substrate (hereinafter referred to as a super-hard substrate) is charged and a heater is provided.
In the apparatus, for example, the atmosphere is vacuumed to 0.5 Pa,
When heated to a temperature of 500 ° C, the anode electrode
Cathode electrode set with Ti-Al alloy having composition
Between the pole (evaporation source), for example, voltage: 35 V, current: 9
Arc discharge is generated under the condition of 0A, and
Nitrogen gas is introduced as a reactive gas, while
Is a condition where a bias voltage of -200V is applied, for example.
On the surface of this, for example, JP-A-62-56565
As described in the report, the composition formula: (Ti_1-XAl_X) N
(However, in atomic ratio, X shows 0.15-0.65.)
Complex nitride of Ti and Al satisfying (hereinafter, (Ti, A
1) N)] layer as a hard coating layer having a thickness of 1 to 20 μm.
Known coated carbide tips are deposited with a uniform thickness.
This is used for continuous and interrupted cutting of steel and cast iron
It is also well known. [0003] SUMMARY OF THE INVENTION In recent years,
High performance is remarkable, while labor saving for cutting process
There is a strong demand for energy saving and cost reduction.
As a result, cutting tools are affected as much as
There is a tendency to require less versatility, but the above conventional coating
For cemented carbide inserts, this must be done with ordinary strips such as steel or cast iron.
No problem when used for continuous or interrupted cutting
However, when used for cutting to do this,
The high mechanical and thermal shocks that occur
Defects such as chipping and chipping (small chipping) easily occur
As a result, the service life is currently relatively short.
is there. [0004] Means for Solving the Problems Accordingly, the present inventors have
From the viewpoints described above, the conventional coated carbide tips
In particular, perform intermittent cutting of steel, cast iron, etc. under heavy cutting conditions.
Coated carbide with excellent cutting resistance at the cutting edge
As a result of research to develop chips,
The cemented carbide substrate that composes the cemented carbide tip was measured using an optical microscope.
The porosity of 2 area% or less is measured by observation of the longitudinal section structure.
Having a composition of Co:
Contains 4 to 20% by mass and Cr: 0.1 to 4% by mass
And the remainder is tungsten carbide as a hard phase forming component
(Hereinafter referred to as WC) and the composition consisting of unavoidable impurities.
The rake face at the cutting edge of the carbide substrate
1, that is, a longitudinal section of a main part of the cutting blade portion is schematically shown in FIG.
As shown in the figure, the cutting edge ridge line where the rake face
On the rake face, at a depth of 20 to 100 μm from the surface
Measurement by observation of longitudinal section structure using optical microscope
And a porous zone in which pores are present at a ratio of 5 to 30 area%.
A part was formed, and the hard coating layer was physically vapor-deposited on this part.
When a coated carbide tip is constructed, the resulting coating
In a cemented carbide tip, it is present in the porous zone portion.
Holes provide sufficient mechanical and thermal shock during cutting
The cutting edge has excellent fracture resistance
With excellent cutting performance over a long period of time
We obtained the research result that it exerts itself. The present invention has been made based on the above research results.
Wherein Co: 4 to
20% by mass and Cr: 0.1 to 4% by mass.
Is composed of WC as a hard phase forming component and unavoidable impurities.
Observation of longitudinal cross-sectional structure using an optical microscope
Pores are present in a ratio of 5 to 30% by area
Porous zone meets rake face and flank face of cutting edge
20 to 1 from the surface on the rake face including the cutting edge ridge
It exists over a depth of 00 μm,
The surface of a cemented carbide substrate having a pore ratio of 2 area% or less
As the coating layer, the composition formula: (Ti_1-XAl_X) N (however,
In the atomic ratio, X represents 0.15 to 0.65).
(Ti, Al) N layer with an average layer thickness of 1 to 20 μm
A coating with a cutting edge that exhibits excellent chipping resistance.
It is characterized by a coated carbide tip. The coated carbide tip of the present invention constitutes
For example, WC powder as raw material powder, Cr
_ThreeC_TwoPowder and Co powder are blended in the prescribed ratio
And mixed to form a mixed powder for forming the body part,
For the formation of the band portion, the raw material powder blended in the above specified ratio
Add paraffin in proportion to the porosity and mix
These mixed powders are mixed in a porous zone.
Press molding while taking into account the thickness of
Then, the green compact is deparaffinized,
In the state where holes are formed in the green compact part for forming
It can be manufactured by sintering. Next, the coated cemented carbide tip of the present invention is used.
The super hard substrate and the hard coating layer constituting the
The reason for limiting the numerical values as described above will be described. (A) Composition of carbide substrate Co component improves sinterability, and thus has strength for super hard substrates
And has the effect of imparting toughness, but its content is
Below 4% by weight, the desired strength and strength, especially in the porous zone
The toughness cannot be ensured, resulting in chipping and
Chipping is likely to occur, while its content is 20
When the amount exceeds%, thermoplastic deformation also occurs in the porous zone.
As a result, uneven wear, which promotes wear, occurs on the cutting edge.
From 4 to 20 mass
%. The Cr component contains Co in the binder phase
Solid solution suppresses grain growth of WC phase, thus forming hard phase
Has the effect of contributing to the refinement of the WC phase
When the amount is less than 0.1% by mass, a desired effect of grain refinement is secured.
When the content exceeds 4% by mass,
Cr carbide began to precipitate, especially in the porous zone.
Rapid decrease in toughness, which can cause defects
Therefore, the content was determined to be 0.1 to 4% by mass. (B) Porous zone portion of the super hard substrate The main body of the cemented carbide substrate contains the cemented carbide
With a porosity of less than 2 area% as in the body
To maintain the specified strength, and
As described above, intermittent cutting is performed under heavy cutting such as high depth of cut and high feed.
Even under the cutting conditions, a large number of vacancies distributed
Absorbs and relaxes thermal and mechanical shocks, causing
It also has the effect of suppressing the occurrence of chipping and other defects.
That's how it works. However, the void in the porous zone
If the porosity is less than 5% by area, a sufficient shock absorbing / mitigating effect can be obtained.
On the other hand, if the porosity exceeds 30 area%,
Sharply drops, causing chipping and chipping at the cutting edge.
The porosity is determined to be 5 to 30% by area because
Was. Also, the depth of formation of the porous zone from the surface of the cemented carbide substrate
If the thickness is less than 20 μm, impact absorption by the porous zone portion
It is not possible to satisfactorily secure the effect of
If the formation depth exceeds 100 μm, the strength of the porous zone
Sharply decreases, resulting in chipping or
Since chipping and other defects are likely to occur,
The formation depth was determined to be 20 to 100 μm. (C) Hard coating layer Al in the (Ti, Al) N layer constituting the hard coating layer
Increases the high-temperature hardness with respect to TiN, thereby improving wear resistance.
To form a solid solution,
Formula: (Ti_1-XAl_X) X value of N is less than 0.15 in atomic ratio
Cannot achieve the desired abrasion resistance.
If the value exceeds 0.65, chipping occurs in the hard coating layer.
Since it is easy to produce, the X value is fixed at 0.15 to 0.65.
I did. If the average thickness of the hard coating layer is less than 1 μm,
The desired abrasion resistance cannot be secured.
When the layer thickness exceeds 20 μm, chipping occurs on the hard coating layer.
, The average layer thickness is 1 to 20 μm.
m. [0010] DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the coated carbide chip of the present invention will be described.
The steps will be specifically described with reference to examples. As raw material powder,
WC powder having an average particle diameter of 1 to 3 μm, Cr
_ThreeC _TwoPowder and Co powder,
Was blended in the composition shown in Table 1 and
Wet mixing for 2 hours, drying, and forming of super hard substrate body
The mixed powders a-1 to a-9 were prepared, and the raw material powder was further prepared.
In addition to paraffin, and these are shown in Table 2.
Blend in the composition and dry mix in a ball mill for 24 hours
And mixed powders b-1 to b
-9, and then mix these powders with a porous band.
Considering the thickness of the area, and the set shown in Table 3
Laminated and filled in a mold by pressing
The green compact is pressed in a nitrogen atmosphere at 60
Deparaffinization treatment at 0 ° C for 1 hour
In the state where pores are formed in the green compact part for forming the quality zone part,
In vacuum, at a temperature within a range of 1350 to 1500 ° C.
Sinter under the condition of holding for 1 hour at the temperature, and finally the cutting edge
Honing of R: 0.05 on the edge line
Gives the composition and porosity shown in Table 3 (ordinary optical
Of the longitudinal cross-sectional structure observed at a magnification of 200 times using a microscope
A body part having a measurement result, the same applies hereinafter) and a cutting blade
The composition, which is located on the rake face of the part, also shown in Table 3,
Porous with porosity and depth (thickness) from the surface
Consists of a band part, and ISO standard CNMG1203
08 of the present invention having a chip shape of
Each was formed. [0011] For comparison purposes, the communication shown in Table 4 is shown.
To form a porous zone on the rake face of the cutting edge.
Except for the difference, the formation conditions of the above-mentioned ultra-hard substrate A1 to A9 of the present invention
The conventional carbide substrates B1 to B9 were formed under the same conditions as
Done. Next, the hard substrates A-1 to A
-9 and conventional carbide substrate B-1 to B-9 in acetone
In the state of ultrasonic cleaning and drying, each is shown in FIG.
Into the arc ion plating system
As a sword electrode (evaporation source)
A Ti-Al alloy was installed, and the inside of the apparatus was evacuated to 1.3 x 1
0^-3While maintaining the vacuum of Pa, the inside of the device
After heating to 00 ° C., Ar gas was introduced into the apparatus and
An Ar atmosphere of 5 Pa was used.
0 V pulse bias voltage is applied to the surface of
r Gas bombarding cleaning, then 1.3 × 10
^-3While maintaining the vacuum of Pa, the inside of the device
With heating to a predetermined temperature in the range of 0 to 700 ° C,
2.8 Pa by introducing nitrogen gas as a reaction gas into the apparatus
And a bar applied to the carbide substrate.
When the bias voltage is set to -150 V, the cathode electrode (T
arc discharge between the i-Al alloy) and the anode electrode
(T) on each surface of the cemented carbide substrate.
The hard coating layer consisting of the (i, Al) N layer
By vapor deposition with the target composition and target layer thickness,
Invention coated carbide tips 1-9 and conventional coated carbide tips 1
To 9 were each manufactured. It should be noted that the resulting
Bright coated carbide tips 1-9 and conventional coated carbide tips 1
Regarding the composition and layer thickness of each hard coating layer of No. 9,
Using an Auger spectrometer and a scanning electron microscope,
Table 5 shows the results of measuring the longitudinal section of the cutting edge.
Composition and average substantially equal to target composition and target layer thickness
The layer thickness (average value of measurement at five locations) is shown. Next, the coated carbide tips 1 to 9 according to the present invention will be described.
And about the conventional coated carbide tip tools 1-9, Work material: JIS / SNCM439 Four at regular intervals in the length direction
Flute round bar, Cutting speed: 100 m / min. , Cut: 3.0 mm, Feed: 0.15 mm / rev. , Cutting time: 5 minutes, High-cut intermittent cutting test of alloy steel under the conditions of Work material: JIS S45C with 4 longitudinal grooves at regular intervals in the length direction
Round bar, Cutting speed: 100 m / min. , Cut: 1.0 mm, Feed: 0.4 mm / rev. , Cutting time: 5 minutes, High feed intermittent cutting test of carbon steel under the conditions of Work material: Four longitudinal grooves at equal intervals in the longitudinal direction of FCD450
rod, Cutting speed: 100 m / min. , Cut: 3.5 mm, Feed: 0.2 mm / rev. , Cutting time: 5 minutes, High-cut intermittent cutting test of spheroidal graphite cast iron under various conditions
The maximum flank wear width of the cutting edge in any cutting test.
Was measured. Table 5 shows the measurement results. [0014] [Table 1] [0015] [Table 2] [0016] [Table 3][0017] [Table 4] [0018] [Table 5][0019] From the results shown in Table 5, it can be seen that the coating of the present invention
The hard tips 1 to 9 all have extremely high thermal and mechanical
Intermittent cutting in heavy cutting conditions of steel and cast iron with mechanical impact
Porous band formed on the rake face of the carbide substrate even when machining
The cutting edge part has excellent mechanical and thermal shock resistance depending on the area
Chipping and chipping
No wear and excellent wear resistance
The formation of a porous zone on the rake face of the carbide substrate
In the conventional coated carbide tips 1 to 9, the heavy cutting conditions
In the intermittent cutting with, chipping or chipping occurs at the cutting edge,
It is clear that the service life is reached in a relatively short time. Up
As described above, the coated carbide tip of the present invention can be used for various steels and
Continuous cutting and intermittent cutting under normal conditions such as cast iron
Theory, especially with heavy mechanical and thermal shock.
Even when used for intermittent cutting under cutting conditions,
Cutting performance.
It can respond satisfactorily to the versatility of machining, and
Possible to save labor and energy, and reduce cost
It is assumed that.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view showing a longitudinal section of a main part of a cutting blade portion of a carbide substrate constituting a coated carbide chip of the present invention. FIG. 2 is a schematic explanatory view of an arc ion plating apparatus.

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[Procedure amendment] [Date of submission] August 24, 2001 (2001.8.2
4) [Procedure amendment 1] [Document name to be amended] Description [Item name to be amended] 0018 [Amendment method] Change [Content of amendment] [Table 5]

   ────────────────────────────────────────────────── ─── Continuation of front page    (72) Inventor Toshiyuki Taniuchi             1511 Furamagi, Ishishita-cho, Yuki-gun, Ibaraki Prefecture             Mitsubishi Materials Corporation Tsukuba Works F term (reference) 3C046 FF03 FF10 FF19 FF25 FF38                 4K029 AA04 BA58 BC02 BD05 CA03                       DD06 EA01

Claims (1)

Claims 1. A binder phase-forming component containing 4 to 20% by mass of Co and 0.1 to 4% by mass of Cr, with the balance being tungsten carbide as a hard phase-forming component and inevitable impurities. Has a composition of, and is measured by observation of a longitudinal cross-sectional structure using an optical microscope,
The porous zone portion in which voids are present at a ratio of 5 to 30% by area has a depth of 20 to 100 μm from the surface at the rake face portion including the cutting edge ridge portion where the rake face and the flank face of the cutting edge portion intersect. Over the surface of the tungsten carbide-based cemented carbide substrate having a pore ratio of 2% by area or less in the other main body portion, as a hard coating layer, a composition formula: (Ti _1-x Al _x ) N ( However, in the atomic ratio, X indicates 0.15 to 0.65), and a composite nitride layer of Ti and Al satisfying the following condition is physically vapor-deposited with an average layer thickness of 1 to 20 μm. Slow-away tip made of surface-coated cemented carbide that exhibits excellent fracture resistance.