JPH0813077A - Nitrogen-containing sintered hard alloy - Google Patents

Abstract

PURPOSE:To obtain the hard alloy extremely excellent in thermal shock resistance by regulating an X-ray diffraction peak of higher intensity on a low angle side so that it has a specific half-width, in a nitrogen-containing sintered hard alloy having a specific composition and having two peaks of B1 structure. CONSTITUTION:The nitrogen-containing sintered hard alloy, which consists of 75-95wt.% of hard phase consisting of Ti and one or more kinds among the carbides, nitrides, and carbonitrides of one or more kinds among the group IVa, Va, and VIa transition metals of the Periodic Table and multiple carbonitrides of them and 5-25wt.% of binding phase containing Ni, Co, and inevitable impurities and in which two peaks of B1 structure are detected by the X-ray diffraction measurement, is prepared. In a peak of higher intensity, detected on a low angle side, between two peaks of B1 structure from the same diffracting plane in the X-ray diffraction measurement of this alloy, the half-width of the X-ray diffraction peak measured in the surface part of the alloy is regulated so that it becomes 40-<60% of the half-width of the X-ray diffraction peak measured in the inner part at a depth of >=1mm from the surface of the alloy. By this method, the alloy usable for wet cutting can be obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nitrogen-containing sintered hard alloy, and particularly as a material for a cutting tool, it has excellent thermal shock resistance, wear resistance and strength, and can be used for wet cutting. The present invention relates to a nitrogen-containing sintered hard alloy.

[0002]

2. Description of the Related Art Sintered hard alloys containing carbon as a main component such as carbonitrides as a hard phase and containing nitrogen bonded with a metal composed of Ni and Co have already been put to practical use as cutting tools. In this nitrogen-containing sintered hard alloy, the high-temperature creep resistance is significantly improved because the hard phase becomes significantly finer than that of the conventional nitrogen-free sintered hard alloy.
It has been widely used as a cutting tool along with so-called cemented carbide containing C as a main component. However, in this nitrogen-containing sintered hard alloy, the thermal conductivity of the carbonitride of Ti, which is the main component, is significantly smaller than the thermal conductivity of WC, which is the main component of the cemented carbide. The thermal conductivity of the hard alloy is about 1/2 of that of the cemented carbide, and the thermal expansion coefficient also depends on the characteristic value of the main component, and that of the nitrogen-containing sintered hard alloy is 1. The resistance to thermal shock is reduced due to such factors as tripled. For this reason, cutting under conditions in which thermal shock is particularly severe, such as milling and lathe cutting of square timber,
In addition, the present situation is that reliability is lower than that of coated cemented carbide and the like for wet-type profile cutting in which the depth of cut varies greatly. Various improvements have been attempted to solve such problems as described below. For example, in Japanese Unexamined Patent Publication (Kokai) No. 2-15139, 50% by weight or more of Ti in terms of carbides, 6a of W, etc.
A group element containing less than 40% by weight in terms of carbide and containing high nitrogen with an atomic ratio of N / C + N of 0.4 to 0.6 improves the surface roughness by controlling the sintering atmosphere, and has a high surface layer. Forming a modified portion having toughness and high hardness is also disclosed in JP-A-5-9.
In Japanese Patent No. 646, a region containing Ti as a main component and containing W, Mo, and Cr in a total amount of less than 40% by weight in terms of carbide is controlled in a cooling step after sintering to reduce a binder phase in the surface portion as compared with the inside. There is disclosed a cermet that forms a groove and leaves a compressive stress on the surface.

[0003]

However, the cermets disclosed in any of the above publications have improved wear resistance and toughness, but have insufficient fracture resistance as compared with coated cemented carbide. Therefore, thermal shock resistance, especially thermal cracking, and sudden cracking due to crack propagation due to both thermal shock and mechanical shock are likely to occur, and sufficient reliability cannot be obtained. That is, in such a prior art, although the manufacturing cost can be reduced by omitting the coating process, only the performance which is commensurate with it can be exhibited. This means that in the category of so-called cermet, which is premised on the inclusion of Ti to a certain extent or more, there is a limit to improving the strength against defects. Therefore, the present inventors have arrived at the present invention as a result of detailed research on analysis of cutting phenomena such as temperature distribution in various cuttings and arrangement of material components in a tool. INDUSTRIAL APPLICABILITY The present invention is a nitrogen for cutting tool which can be used with high reliability without surface coating even in processing under severe thermal shock that could only be used with conventional expensive coated cemented carbide. An object is to provide a sintered hard alloy containing.

[0004]

In a nitrogen-containing sintered hard alloy, the hard phase particles have a so-called cored double structure, as disclosed in Japanese Patent Publication No. 56-51201.
It is formed of a core portion enriched with i and N and a peripheral portion enriched with W and Mo and depleted of N. When an X-ray diffraction measurement (Cu-Kα ray) is performed on such an alloy having a double structure, as shown in FIG. 1, the strong peaks on the low angle side of the diffraction angle are in the peripheral portion, and the high-angle intensity is high. The low peak of is for the core.

The inventors of the present invention have proposed a conventional expensive coated cemented carbide, which does not cause thermal shock resistance, particularly thermal cracking, or sudden cracking due to crack propagation caused by both thermal shock and mechanical shock. It is not necessary to apply a surface coating for machining under conditions subject to severe thermal shock, which could only be used, such as milling and lathe cutting of square timber, and wet profile cutting where the cutting depth fluctuates greatly. We have conducted intensive research to develop a nitrogen-containing sintered hard alloy for cutting tools that can be used reliably. As a result, the composition of the alloy surface
The finding that reducing the proportion of the core portion of the cored structure and making the structure abundance ratio of the peripheral portion large and homogeneous and less strain can significantly improve wear resistance, thermal shock resistance and toughness And reached the present invention.

That is, the nitrogen-containing sintered hard alloy of the present invention comprises, firstly, Ti and at least one transition metal carbide or nitride other than Ti selected from the groups 4a, 5a and 6a of the periodic table. 75 to 95% by weight of hard phase composed of at least one kind of carbonitride or composite carbonitride
And the binder phase containing Ni and Co and inevitable impurities is 5
In the nitrogen-containing sintered hard alloy in which two peaks of B1 structure are detected by X-ray diffraction measurement,
The half width (hereinafter referred to as the half width) of the X-ray diffraction peak of the peak with the higher intensity detected on the low angle side of the peaks from the same diffraction surface of the two B1 structures in the line diffraction measurement is the alloy. Half width measured on the surface is 1 mm of alloy
The nitrogen-containing sintered hard alloy is characterized in that it is 40% or more and less than 60% with respect to the half width measured inside.

The second invention is the same nitrogen-containing sintered hard alloy, and in the peaks from the same diffraction plane of two B1 structures in X-ray diffraction, the intensity of the small peak detected on the high angle side of the diffraction angle. Is I _s , the intensity of the peak with high intensity detected on the lower angle side of the diffraction angle is I _L, and the peak intensity ratio represented by I _s / I _L on the alloy surface is I
_H, is I _H / I _N when the peak intensity ratio represented by I _s / I _L inside 1mm or more alloy was I _N, 0.0
It is a nitrogen-containing sintered hard alloy characterized by being 1 or more and 0.95 or less. It is preferably 0.01 or more and 0.3 or less.

A third aspect of the present invention is the same nitrogen-containing sintered hard alloy, the X-ray diffraction peak measured within 1 mm or more of the alloy at the peak position of the peak of high intensity detected on the low angle side of the X-ray diffraction angle. The nitrogen-containing sintered hard alloy is characterized in that the X-ray diffraction peak position measured at the alloy surface portion with respect to the position is present on the low angle side.

The fourth invention is characterized in that the WC phase is present in the same nitrogen-containing sintered hard alloy, but it is necessary that the WC phase is hardly present. Specifically, the WC (110) peak is required. the larger the peak intensity of the intensity detected in the low angle side of the intensity of the I _WC, two B1 structure (220) peak and I _B1, is represented by I _WC / I _B1 inside than 1mm alloys that when the intensity ratio I _WN, the intensity ratio expressed by I _WC / I _B1 at the alloy surface portion was I _WH, below 0.95 I _WN is 0.1 or more, I _WH / I _WN 0 It is a nitrogen-containing sintered hard alloy characterized by being less than 0.2. Fifth
Of the invention is the above-mentioned first and second inventions, the sixth invention is the above-mentioned third and first or fifth inventions, and the seventh invention is the above-mentioned fourth and first, fifth or sixth inventions. Are combined with each other.

[0010]

The reason for limitation in the present invention will be described in detail below. If the hard phase in the present invention is less than 75% by weight, abrasion resistance and plastic deformation resistance are significantly deteriorated, and if it exceeds 95% by weight, strength and toughness are insufficient, which is not preferable. The half-value width of the peak of the surface portion of the present invention having a higher intensity is 40% or more and less than 60% of the inner half-value width. If it is less than 40%, the plastic deformation resistance is poor, and if it is 60% or more, the thermal shock resistance is insufficient, which is not preferable. I _H / I _N of the present invention is 0.0
If it is less than 1, it cannot be manufactured substantially, and if it exceeds 0.95, the desired thermal shock resistance cannot be obtained. A desirable upper limit value is 0.3. Further, in the peak position of the peak having a high intensity of the X-ray diffraction angle in the present invention, when the peak position measured on the surface portion is on the low angle side with respect to the peak position measured internally, the desired thermal shock resistance and abrasion resistance are obtained. However, if it exists on the high angle side, the thermal shock resistance and the plastic deformation resistance are particularly poor. For example, in the case of a diffraction curve from the (220) plane of the B1 structure that can be detected by a Cu-Kα ray of X-ray near a diffraction angle of 61 degrees (see FIG. 2), the diffraction angle of the surface portion is 0.01 to
It is necessary to shift to the low angle side by 0.2 degrees.

Further, the present invention is characterized in that the WC phase is present inside and is hardly present on the surface portion,
If I _WN is less than 0.1, crack propagation resistance is insufficient and the toughness is significantly deteriorated. If I _WN is 0.95 or more, a large amount of WC phase remains on the surface. I _WH / I _WN cannot be less than 0.2. Wear resistance when I _WH / I _WN exceeds 0.2
Crater wear resistance (wear caused by chemical reaction such as high temperature diffusion wear with the work material) deteriorates, which is not preferable.

The nitrogen-containing sintered hard alloy of the present invention is generally selected from Ti and T selected from Groups 4a, 5a and 6a of the Periodic Table.
Carbonitride powder containing at least one transition metal other than i, WC powder, and iron group metal powder of Ni or Co are wet-mixed and then pressed and molded into a vacuum of about 1 to 10 ^-2 Torr from 1000 to After degassing at 1200 ° C., nitrogen gas partial pressure 2 to
Sintered at 1400 to 1500 ° C. for 0.5 to 3 hours at 70 Torr and 0.5 in a vacuum of 10 ⁻⁵ to 10 ⁻¹ Torr.
Prepare by cooling at a rate of -10 ° C / min. The average particle size of the raw material is preferably 0.5 to 5 μm by the above method.

The other embodiments of the present invention will be summarized below. (1) A combination of the first invention and the third and fourth inventions (2) At least one of the second invention and the third and fourth inventions
A combination of two. (3) A combination of the third invention and the fourth invention. (4) After wet mixing Ti and carbonitride powders containing at least one transition metal other than Ti selected from groups 4a, 5a, and 6a of the periodic table, WC powders, and iron group metal powders of Ni and Co, After pressing and molding, degassing in a vacuum of about 1 to 10 ^-2 Torr at 1000 to 1200 ° C, and then partial pressure of nitrogen gas 2 to
Sintered at 1400 to 1500 ° C. for 0.5 to 3 hours at 70 Torr and 0.5 in a vacuum of 10 ⁻⁵ to 10 ⁻¹ Torr.
The method for producing a nitrogen-containing sintered hard alloy according to any one of claims 1 to 7 or any of the above (1) to (3), characterized by cooling at a rate of -10 ° C / min. . (5) The method for producing a nitrogen-containing sintered hard alloy as described in (4) above, wherein the raw material powder has an average particle size in the range of 0.5 to 5 μm.

[0014]

EXAMPLES The present invention and the following examples will be explained in more detail below, but the present invention is not limited thereby. [Example 1] With an average particle size of 2 μm, the outer portion of the cored structure looks white with a reflection electron microscope, and the core looks black (Ti _0.85 Ta _0.05 Nb _0.04 W _0.06 ) (C _0.55 N _0.45 ).
Powder, 0.7 μm WC powder, and 1.5 μm N
i powder and Co powder are 45 wt%, 40 wt%,
Wet-mixing 7% by weight and 8% by weight, and then press-molding to obtain 10
After degassing in a vacuum of ^-2 Torr at 1200 ° C, sintering at 1450 ° C for 1 hour at a nitrogen gas partial pressure of 20 Torr, and then in vacuum.2.
Sample 1 was prepared by cooling at 5 ° C / min. X of this sample 1
Line of Cu-Kα line B1 structure, the half-value width (hereinafter, referred to as the half-value width) of the peak of the intensity of the diffraction curve from the (220) plane is 0.27 degrees within 1 mm from the surface, and the surface wrapping is performed. In terms of surface, it decreased to 0.14 degrees and 52%. 35% by weight of TiCN and TaC so as to have the same alloy composition as Sample 1.
4% by weight, 2% by weight of NbC, 44% by weight of WC, 7% by weight of Ni, 8% by weight of Co were mixed and sintered under the same conditions as those of the sample 1, 46% by weight of TiCN, 8% by weight of TaC,
Mo2C 8% by weight, WC 20% by weight, Ni 6% by weight, C
o 12 wt% was blended and sintered under the same conditions as Sample 1 and Sample 3
The same partial pressure as the sample 1 and sample 2 with a nitrogen partial pressure of 5
Samples 4 and 5 were prepared by sintering at 1400 ° C. with Torr and cooling at a CO partial pressure of 200 Torr. The respective (front half width) / (inner half width) is 62%, 63
%, 76% and 71%. A tool shape CNMG432 was prepared with a sintered surface of each of the nitrogen-containing sintered hard alloys of Samples 1 to 5 and a cutting test for thermal shock resistance evaluation was performed as described below. (Sample 1
Is the product of the present invention, and samples 2 to 5 are comparative products)

Thermal shock resistance cutting test

[Table 1] As a result, although only two samples 1 were missing, samples 2-5
Had 14, 16, 18, and 13 defects, respectively.

Example 2 (Ti with an average particle size of 2 μm)_0.87
Nb_0.07W_0.06) (C_0.5N_0.5) Powder and same 1.5μ
85% by weight of Ni powder and 7% by weight of Co powder, respectively.
%, 8 wt% by wet mixing, and then press molding, 10^-2Torr
Nitrogen gas partial pressure 5 Torr after degassing at 1200 ℃ in vacuum
After sintering at 1450 ° C. for 1 hour, cooling as shown in Table 1
I described together _H/ I_N(X-ray Cu-Kα ray B1 structure
(Using the diffraction curve from the (220) plane). these
The following abrasion resistance test and thermal shock test in Example 1 were performed.
The results are shown in Table 1.

Wear-resistant cutting test

[Table 2]

[0018]

[Table 3] Slow cooling: 3 to 10 ° C / min Super slow cooling: 0.5 to 5 ° C / min Furnace cooling: 5 to 15 ° C / min Rapid cooling: 10 to 100 ° C / min

Example 3 (Ti _{0.85 with} an average particle size of 2 μm)
Ta _0.05 Nb _0.04 W _0.06 ) (C _0.55 N _0.45 ) powder, 0.7 μm WC powder, 1.5 μm Ni powder and C
o 52% by weight, 30% by weight, 10% by weight, and 8% by weight of powder were wet-mixed with each other, and subjected to embossing molding to obtain 10 ^-2 Torr
Nitrogen gas partial pressure 20To after degassing at 1200 ℃ in vacuum
rr at 1480 ° C. for 1 hour, then in vacuum at 1.5 ° C. /
Sample 13 was prepared by cooling in minutes. 38% by weight of TiCN, 4% by weight of TaC, 2% by weight of NbC, 38% by weight of WC, 10% by weight of Ni, and 8% by weight of Co were mixed so as to have the same alloy composition as the sample 13, and the sample 14 was sintered under the same conditions as the sample 13, and 46% by weight of TiCN, 8% by weight of NbC, 8% by weight of Mo2C, 20% by weight of WC, 10% by weight of Ni, and 8% by weight of Co were mixed and sintered under the same conditions as the sample 13 to obtain a sample 15 and an embossed compact identical to the samples 13 and 15. Sintered at 1430 ℃ with nitrogen partial pressure of 15 Torr and CO partial pressure of 180 Torr
And cooled to prepare Samples 16 and 17, respectively. Further, the same embossed molded body as Samples 13 and 15 was subjected to nitrogen partial pressure 1
Sintered at 1430 ° C at 5 Torr, cooled at 5 ° C in vacuum,
Samples 18 and 19 were prepared.

Diffraction angle deviation angle (deviation to a low angle) from the internal peak position of the peak position of the surface portion using the diffraction curve from the (220) plane of the Cu-Kα ray B1 structure of each X-ray. -, The deviation to a high angle is +), and a tool shape CNMG432 was prepared with a sintered skin using the nitrogen-containing sintered hard alloy of each sample, and the cutting test (2) for the thermal shock resistance evaluation described below was performed. The results are shown in Table 2.

[0021]

[Table 4]

[0022]

[Table 5]

Example 4 (Ti _{0.85 with} an average particle size of 2 μm)
Ta _0.09 W _0.06 ) (C _0.6 N _0.4 ) powder and 0.7μ
m WC powder and the same 1.5 μm Ni powder and Co powder of 45% by weight, 40% by weight, 8% by weight and 7% by weight, respectively.
Wet-blended and then stamped and molded in a vacuum of 10 ^-2 Torr.
After degassing at 200 ℃, nitrogen gas partial pressure up to 1480 ℃ 5
After gradually increasing to -20 Torr and sintering at 1480 ° C for 1 hour, sample 20 was prepared by cooling in vacuum at 2 ° C / min. Sample 20
35% by weight of TiCN and Nb so that the same alloy composition as
C6 wt%, WC44 wt%, Ni8 wt%, Co7 wt% were mixed and sintered under the same conditions as Sample 13, and Sample 21 was used. TiCN 46 wt%, NbC8 wt%, Mo2C8
% By weight, 20% by weight of WC, 10% by weight of Ni and 8% by weight of Co were mixed together and sintered under the same conditions as the sample 20 to prepare a sample 22. Each I _WN and I _WH / I _WN of the sample 20 was 0.4.
1, 0.05, sample 21 0.55, 0.51, sample 2
2 was 0.01 or less and 0.01 or less. Sample 20-
As a result of carrying out the same abrasion-resistant cutting test as in Example 2 using No. 22, V _B was 0.14 mm and 0.29 m, respectively.
m and 0.33 mm. Further, as a result of performing a thermal shock resistance cutting test (2) similar to that of Example 3, the number of defective cutting edges was 3, 18, and 13, respectively. (Sample 20 is a product of the present invention, and samples 21 to 22 are comparative products).

[Example 5] Sample 23 had an average particle size of 2
μm (Ti_0.85Ta_0.05Nb_0.04W_0.06) (C _0.55N
_0.45) Powder, 0.7 μm WC powder, 1.5 μm
m Ni powder and Co powder are 47% by weight and 38% by weight, respectively.
%, 7% by weight, 8% by weight, and tested as sample 24.
37 weight of TiCN so that it has the same alloy composition as material 23
%, TaC 4% by weight, NbC 2% by weight, WC 42% by weight
%, Ni 7 wt%, Co 8 wt%, and Sample 2
4 as TiCN 50% by weight, TaC 2% by weight, NbC
8 wt%, Mo2C5 wt%, WC19 wt%, Ni8
% By weight and Co 8% by weight, and after wet-mixing each of them,
Molded and molded, 10^-2Degas at 1200 ° C in a Torr vacuum
After that, bake for 1 hour at 1450 ° C with a partial pressure of nitrogen gas of 20 Torr.
After binding, cool at 2 ° C / min in a vacuum, and insert a sintered skin chip for cutting
CNMG432 was created. Also, the same as Samples 23-25
Like sintering and cooling only at a CO partial pressure of 200 Torr
Were designated as Samples 26, 27 and 28, respectively. each
(Full width at half maximum) / (Full width at half maximum), I_H, I_N, I
_H/ I_N((220) plane of Cu-Kα ray B1 structure of X-ray
From the above), peak position deviation angle, I_WN, I
_WH/ I_WNA wear resistance cutting test result similar to that of Example 2,
The same thermal shock resistance cutting test (2) as in Example 3 was carried out.
As a result, the following toughness test results are also shown in Table 3. (Sample 2
3 is the product of the present invention, and samples 24 to 28 are comparative products)

Toughness cutting test

[Table 6]

[0026]

[Table 7]

[0027]

As described above, according to the present invention, as a cutting tool, cutting under particularly severe conditions of thermal shock, for example, milling cutting or cutting with a lathe of square timber, and wet copying with greatly varying cutting depth. It has an effect that a highly reliable nitrogen-containing sintered hard alloy can be provided without a coating to a processing region such as a cutting process which can be conventionally used only with an expensive coated cemented carbide tool.

[Brief description of drawings]

FIG. 1 is a diffraction curve from a typical B1 structure (422) plane of X-ray CU-Kα line of a nitrogen-containing sintered hard alloy having a cored double structure.

FIG. 2 is a diffraction curve from a B1 structure (220) plane of an X-ray Cu-Kα line of a nitrogen-containing sintered hard alloy having a cored double structure.

3 (a) is a surface portion of Sample 23 in Example 5, FIG.
(B) An internal X-ray Cu-Kα ray diffraction curve.

FIG. 4 is a diffraction curve of an X-ray Cu-Kα ray of (a) surface portion and (b) inside of the sample 24.

5A and 5B are diffraction curves of X-ray Cu-Kα ray of (a) surface portion and (b) inside of Sample 25, respectively.

Claims (7)

[Claims] 1. At least one of a carbide, a nitride, a carbonitride or a composite carbonitride of Ti and at least one transition metal other than Ti selected from the groups 4a, 5a and 6a of the periodic table. 75 to 95% by weight of a hard phase consisting of one or more species, 5 to 25% by weight of a binder phase containing Ni and Co and inevitable impurities, and 2 types of peaks of B1 structure detected by X-ray diffraction measurement. In sintered hard alloy,
Of the two peaks from the same diffraction plane of the B1 structure in the X-ray diffraction measurement, the half-value width of the X-ray diffraction peak measured at the alloy surface portion is the peak with the higher intensity detected on the low angle side. Nitrogen-containing sintered hard alloy, characterized in that it is 40% or more and less than 60% with respect to the half width of the X-ray diffraction peak measured inside 1 mm or more. 2. At least one of a carbide, a nitride, a carbonitride or a composite carbonitride of Ti and at least one transition metal other than Ti selected from the groups 4a, 5a and 6a of the periodic table. 75 to 95% by weight of a hard phase consisting of one or more species, 5 to 25% by weight of a binder phase containing Ni and Co and inevitable impurities, and 2 types of peaks of B1 structure detected by X-ray diffraction measurement. In sintered hard alloy,
In the peaks from the same diffraction plane of two B1 structures in X-ray diffraction, the intensity of the peak having a small intensity detected on the high angle side of the diffraction angle is I _s , and the intensity of the peak having a high intensity detected on the low angle side of the diffraction angle is large. Let I _L be the strength of
_The peak intensity ratio expressed by _s / I _L is I _H , the alloy is 1 mm
The peak intensity ratio represented by I _s / I _L in the above is I _N
And I _H / I _N when the is a nitrogen-containing sintered hard alloy, wherein the at 0.01 to 0.95. 3. At least one of a carbide, a nitride, a carbonitride or a composite carbonitride of Ti and at least one transition metal other than Ti selected from the groups 4a, 5a and 6a of the periodic table. 75 to 95% by weight of a hard phase consisting of one or more species, 5 to 25% by weight of a binder phase containing Ni and Co and inevitable impurities, and 2 types of peaks of B1 structure detected by X-ray diffraction measurement. In sintered hard alloy,
At the peak position of the high intensity peak detected on the lower side of the X-ray diffraction angle, the X-ray diffraction peak position measured on the alloy surface is lower than the X-ray diffraction peak position measured inside the alloy of 1 mm or more. Nitrogen-containing sintered hard alloy characterized by existing on the corner side. 4. At least one of a carbide, a nitride, a carbonitride or a composite carbonitride of Ti and at least one transition metal other than Ti selected from the groups 4a, 5a and 6a of the periodic table. 75 to 95% by weight of a hard phase consisting of one or more species, 5 to 25% by weight of a binder phase containing Ni and Co and inevitable impurities, and 2 types of peaks of B1 structure detected by X-ray diffraction measurement. In sintered hard alloy,
The intensity of the (110) peak of _WC is I _WC , and the intensity of the peak having the higher intensity detected on the lower angle side of the (220) peaks of the two B1 structures is I _B1, and I _{WC within} 1 mm or more of the alloy When the strength ratio represented by / I _B1 is I _WN and the strength ratio represented by I _WC / I _B1 on the alloy surface is I _WH , I _WN is 0.1 or more and less than 0.95, and I A nitrogen-containing sintered hard alloy having a _WH / I _WN of 0.2 or less. 5. The identity of two B1 structures in X-ray diffraction
In the peak from the diffraction plane, it is detected on the high angle side of the diffraction angle.
The intensity of the peak with a small intensity_S, Low angle side of diffraction angle
The intensity of the peak with high intensity detected in_LAnd then
I on the gold surface_S/ I_LThe peak intensity ratio represented by
I_H, I within 1 mm of alloy_S/ I _LRepresented by
The peak intensity ratio is I_NI when_H/ I_NBut 0.0
It is 1 or more and 0.95 or less, It describes in Claim 1 characterized by the above-mentioned.
The listed nitrogen-containing sintered hard alloy. 6. The X-ray diffraction measured on the alloy surface portion with respect to the X-ray diffraction peak position measured inside 1 mm or more of the alloy at the peak position of the high intensity peak detected on the low angle side of the X-ray diffraction angle. The nitrogen-containing sintered hard alloy according to claim 1 or 5, wherein the peak position is on the lower angle side. 7. The intensity of the (110) peak of _WC is I _WC ,
Of the (220) peaks of the two B1 structures, the intensity of the peak having a high intensity detected on the low angle side is defined as I _B1 and the intensity of the alloy is 1
The strength ratio represented by I _WC / I _B1 inside mm or more is I _WN ,
_Assuming that the strength ratio represented by I _WC / I _B1 on the alloy surface is I _WH , I _WN is 0.1 or more and less than 0.95, and I _WH / I _WN
Is 0.2 or less, The nitrogen-containing sintered hard alloy according to claim 1, 5 or 6, characterized in that.