JPS5854182B2 - Oxygen-containing tungsten/titanium carbide-based sintered hard alloy - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an oxygen-containing tungsten-titanium carbide (hereinafter referred to as (W)) which exhibits particularly excellent cutting properties when used as a cutting tool material.

Ti)C)-based sintered hard alloys.

Conventionally, sintered hard alloys generally include: (a) WCC cemented carbide containing tungsten carbide (hereinafter referred to as WC) as a main component; (b) titanium carbide (hereinafter referred to as TiC) and titanium nitride (hereinafter referred to as TiN). ), or cermet (C) containing titanium carbonitride (hereinafter referred to as T1CN) as a main component, aluminum oxide (hereinafter referred to as Al2O3)
It has been broadly classified into ceramics containing as the main component.

Among these conventional sintered hard alloys, ceramics are superior to the above-mentioned WC in terms of toughness when used as cutting tools.
A1□ as it is inferior to C cemented carbide and cermet.
The excellent heat resistance, oxidation resistance, and welding resistance of 03 cannot be fully utilized, and therefore it is only put into practical use in a few limited fields.

In addition, most of the above cermets are mainly composed of TiC, and since TiC has inferior toughness and plastic deformation resistance compared to WC, this TiC-based cermet cannot be used during interrupted cutting under heavy loads. There is a problem in that TiC-based cermets are prone to chipping when used for cutting, black scale cutting, and cutting of high-hardness materials.Therefore, research on improving the toughness of TiC-based cermets has been actively conducted. It has been studied to improve toughness by adding components such as W or WC, TiN or T1CN to cermet.

It is true that W or WC is added to the conventional TiC-based cermet mentioned above.
When the component is added, this W or WC becomes TiC.
TiC forms a solid solution in the surrounding structure called the intermediate phase surrounding TiC, forming a double structure with TiC as the core, improving the wettability between the hard phase and the binder phase. This cermet does not have high strength because no improvement in strength has been essentially achieved.

Furthermore, when TiN is added to the conventional TiC-based cermet, as is well known, this TiN is the most stable compound among transition metal nitrides, along with zirconium nitride (hereinafter referred to as ZrN), and has high thermal conductivity. In addition to its excellent heat shock resistance and thermal shock resistance, it acts to suppress the grain growth of the hard phase during sintering and the development of relatively brittle surrounding structures, improving the toughness of the cermet. However, in order to impart the desired toughness to the cermet, it is necessary to add a large amount of it.

However, when such a large amount of TiN is added to a cermet, the wettability of TiN with the binder phase deteriorates, and cavities and bores (small pores) are easily formed in the cermet structure, resulting in a significant decrease in the strength of the cermet. At present, it is not possible to contain a large amount of TiN, and as a result, it is not possible to obtain a product with the desired excellent toughness.

Furthermore, as mentioned above, it has been considered to improve the toughness of cermets by adding T1CN to TiC-based cermets or by including T1CN as a main component. Judging from the fact that there is almost no difference in alloy properties and cutting performance when compared to the above-mentioned cermets containing TiCN-based cermets for the same purpose, it is clear that the T1CN-containing cermets and the TiCN-based cermets have essentially high performance. It is understood that it does not have strength and toughness.

As mentioned above, in cermets made by adding W or WC, TiN or TiCN to TiC-based cermets, as well as in TiN-based and T1CN-based cermets, the hard phase is fine, so the alloy hardness increases. However, the strength of the hard phase has not been essentially improved, so it does not have high strength, and its toughness is not as good as WCC cemented carbide.

- WCC cemented carbide is superior to the conventional cermets mentioned above in terms of toughness, but the WCC component has heat resistance, oxidation resistance,
And in terms of welding resistance, since it does not contain TiC component, when the WCC cemented carbide is used for cutting that requires heat resistance and oxidation resistance, such as high-speed cutting, it is better than the TiC-based cermet. This shows extremely poor cutting performance.

Because of this, WCC components also have heat resistance, oxidation resistance,
and (W, Ti)C components and T with excellent welding resistance.
WC-(W
, Ti) C-TaC-C.

The PLO grade of the WCC type cemented carbide is mainly used for high-speed cutting.
Depending on the grade, when the cutting speed exceeds 200 m/min, the wear of the cutting tool, especially crater wear, is so severe that it is practically unusable.

Furthermore, cutting tools used for heavy cutting, which generate a large amount of heat during cutting and which also place large stress on the cutting edge, are required to have high heat resistance, plastic deformation resistance, and impact resistance. P30 grade of WCC cemented carbide JI8 classification is often used, but this P30 grade has heat resistance and plastic deformation resistance, but it lacks impact resistance, and conversely, it has poor impact resistance. P30 grade does not have all of heat resistance, plastic deformation resistance, and impact resistance. When this is used for heavy cutting with large feed and depth of cut, it does not exhibit excellent cutting performance.

As mentioned above, conventional WCC cemented carbide and conventional cermets each have cutting areas in which they are not good at cutting, and in particular, in cutting where toughness is important, it is better to use toughness rather than cermets that have many limiting conditions. The above-mentioned WCC cemented carbide will be widely used.

However, as mentioned above, conventional WC-based sintered alloys have not yet shown sufficiently satisfactory cutting performance not only in high-speed cutting but also in heavy-duty cutting, where their toughness can be utilized. In order to expand the cutting area of cemented carbide, it is necessary to simultaneously improve its heat resistance, oxidation resistance, welding resistance, plastic deformation resistance, and impact resistance.

From the above-mentioned viewpoints, the present inventors conducted research to obtain a sintered hard alloy that has heat resistance, oxidation resistance, welding resistance, plastic deformation resistance, and impact resistance at the same time. (a) W/Ti molar ratio: 1/4 to 1/1 (W.

The sintered hard alloy containing Ti)C as a main component is WC
It has the excellent impact resistance of TiC and the excellent abrasion resistance of TiC.

(b) An iron group metal containing one or more Cr group metals as necessary for the purpose of improving the high temperature strength of the alloy and the wettability with the hard phase during sintering. 5 to 5 as one or more types as bonded phase C component
A (W, Ti)C-based sintered hard alloy containing 30% by volume has a molar ratio of oxygen to the total amount of oxygen, carbon and nitrogen, or both, of 0.2 or less. , Ti carbonates, nitrides, and carbonitrides,
and Ti', and 4a of the periodic table excluding Ti.

One or two carbonates, nitoxides, and carbonitrides (hereinafter collectively referred to as carbonitoxides) of one or more of group 5a and 6a metals When the above is contained in a ratio of 1 to 50% by volume, the charcoal
Nitoxide has the following characteristics: ■ It is uniformly and finely dispersed in a spherical state.

■ Particles are less likely to stick together.

■ Excellent heat resistance, oxidation resistance, and welding resistance, and does not reduce alloy strength.

■ Suppress grain growth of (W, Ti)C.

Because of these characteristics, the (W, Ti)C-based sintered hard alloy has excellent heat resistance, oxidation resistance, and welding resistance, as well as excellent impact resistance. , It will now exhibit excellent cutting performance when used in high-speed cutting and heavy-duty cutting, which were traditionally weak points for WCC cemented carbide.

(c) Carbides of metals from groups 4a, 5a, and 6a of the periodic table excluding (W, Ti) C in a range of 1 to 50% by volume to the above (W, Ti) C-based sintered hard alloy. ,
When one or more of nitrides and carbonitrides (hereinafter collectively referred to as carbonitrides) are contained, the wear resistance of the alloy is further improved.

The findings shown in (a) to (c) IJ have been obtained above.

This invention has been made based on the above knowledge, and the technical reason for limiting the numerical values as described above will be explained below.

(1) Molar ratio of N7 in (W, Ti)C If the molar ratio of W/Ti in (W, Ti)C, which is the main component of the alloy of this invention, is less than 1/4, the Ti to W
If the relative content ratio of Ti becomes too large, that is, WC becomes Ti.
If the ratio is too small compared to C, the excellent plastic deformation resistance and impact resistance of WC cannot be fully exhibited. On the other hand, if the ratio W/Ti exceeds 1/1, the relative If the content ratio becomes too high, i.e., TiC is too small compared to WC, TiC's excellent heat resistance, oxidation resistance, and welding resistance cannot be fully exhibited, so the molar The ratio was limited to IA~l/l.

(2) Content of carbon/nitride oxides If the content is less than 1 volume, the desired excellent heat resistance, oxidation resistance, welding resistance, and impact resistance cannot be imparted to the alloy. On the other hand, if the content exceeds 50%, the sinterability will deteriorate, and cavities and bores will easily form in the alloy structure, reducing impact resistance. It was determined that

(3) 0/(C+0), 0/(N
+O), and 0/(C+N+0) molar ratio If these molar ratios exceed 0.2, the oxygen content will be too high and the sinterability will deteriorate, making it easy for cavities and bores to form in the alloy structure. As a result, the impact resistance deteriorates, so the molar ratio was limited to 0.2 or less.

(4) Content of carbon/nitride If the content is less than 1 volume φ, the desired wear resistance cannot be ensured, so it is necessary to contain 1% or more.
If the content exceeds 50 capacity φ, the excellent heat resistance, oxidation resistance, welding resistance, plastic deformation resistance, and impact resistance of (W, Ti)C will not be fully exhibited. Therefore, the content was determined to be 1 to 50 volumes.

(5) Content of Cr group metals and iron group metals If the content is less than 5 volumes, the impact resistance of the alloy will deteriorate, while if the content exceeds 30 volumes, the wear resistance of the alloy will deteriorate. Since it will deteriorate, the content should be reduced to 5 to 3.
It was defined as 0 capacity rice cake.

The (W, Ti)C-based hard alloy of this invention is
Carbon/nitride oxide powder as raw material powder can be produced by ordinary powder metallurgy, for example, by mixing (a) titanium oxide (TiO2) powder, TiC powder and carbon (C) powder. and temperature 1600~200
Titanium carbonate (hereinafter referred to as Ti(CO)) powder is produced by reacting at 0°C, or a mixed powder of Ti(Co) powder and TiN powder or Ti(CN) powder is reacted at the above temperature. To react, titanium carbonitoxide (
A powder (hereinafter referred to as Ti (CNO)) is produced.

(b) The above 'ri(CO) powder is heated to a temperature of 1,600 to 2,000° C. in an N2 or NH3 atmosphere and reacted to produce Ti(CNO) powder.

(c) Ti (CN) powder or TiN powder, Tt02 powder and C powder were mixed and heated to a temperature of 1600.
Ti (CN0
) powder or titanium nitride oxide (hereinafter referred to as Ti (No)) powder is manufactured.

(d) When producing a powder in which a portion of Ti in the above Ti(CNO) is substituted with one or more metals of groups 4a, 5a and 6a of the periodic table, the above Ti02.
4a, 5a of the periodic table as appropriate for TiC, TiN, and Ti(CN) powders.

It is produced by mixing one or more of group 6a metal oxide powder, carbide powder, nitride powder, and carbonitride powder, and similarly subjecting the mixture to a high-temperature heating reaction.

It can be prepared by a method such as.

Next, the (W, Ti)C-based sintered hard alloy of the present invention will be explained through examples and in comparison with comparative examples.

Example 1 As a raw material powder, an average particle size of 1.0 μm was obtained, w/Ti
The molar ratio of (W, T
i) C powder, 1.5 μm thick, C:N:0 molar ratio 0.55:0.30:0.15, i.e. 0.1
5/(0,55+0.30+O,l 5 ) −0,
Ti(C) according to the invention with an oxygen molar ratio of 15
NO) powder, the same 1.5 μm, the molar ratio of C:N:O is 0.45:0.30:0.25, i.e. 0.2
5/(0,45+0.30 +0.25) = 0.
Ti (CNQ) powder outside the scope of this invention with an oxygen molar ratio of 25, Co powder of 1.0 μm, N
Using i powder and Mo powder, these raw material powders are blended in appropriate amounts so as to have the alloy composition shown in Table 1,
This blended powder is pulverized and mixed in a ball mill, then a green compact is formed from the mixed powder, and the green compact is held in vacuum at a temperature of 1450°C for 1 hour and sintered. 5 and Comparative Alloys 1-3 were produced.

Next, the above-mentioned present invention alloys 1 to 5, the above-mentioned comparative alloys 1 to 3,
and conventionally known as cutting tool material *Kuruni 01.
Cutting test chips with shapes conforming to Cl5 (Cemented Carbide Tool Association Kikare) and 5NP432 were manufactured from conventional alloys 1 to 3 of PIO and P2O, and cutting test chips were prepared under cutting conditions A to D shown in Table 2. Continuous and interrupted cutting tests were carried out by applying either of the following conditions, and flank wear and crater wear were measured in the continuous cutting test, and which of the six test cutting edges (chips) was measured in the interrupted cutting test. We measured whether defects occurred in each individual.

The results of these measurements are shown in Table 3.

Table 3 also shows the polished surface condition of the alloy structure.

As is clear from the results shown in Table 3, in cutting high-hardness materials such as chilled rolls, that is, under continuous cutting conditions A, alloys 1 and 2 of the present invention were compared to comparative alloy 1 and conventional alloy (KOI) I. In addition, alloys 1 and 2 of the present invention have excellent impact resistance compared to conventional alloy (KOI) 1 even in interrupted cutting of steel, that is, under interrupted cutting conditions C/1. It shows.

Also in high-speed cutting of steel, that is, continuous cutting condition B and interrupted cutting condition DI, the present invention alloys 3 to 5 are compared to comparative alloys 2 and 3 and conventional alloy 2 (PIO).

It shows extremely superior abrasion resistance and impact resistance compared to No. 3 (P2O).

Example 2 Raw material powders each having an average particle size of 1.5 μm were obtained, (a) W: Ti = 45%: 55% (by weight), C: N:
(W, Ti) (CNO) according to the invention with a molar ratio of 0 = 0.5: 0.4: 0.1
Powder, (b) Ti:Ta:Zr=70%:20%:
10% (weight%), C:N:0=0.5:0
．． (Ti, Ta) according to the invention with a molar ratio of 3:0.2.

Zr) (CNO) powder, (c) Ti:Nb:V=40%:50%:10
% (excellent weight), C: N: 0=0.4: 0.5
: according to the present invention with a molar ratio of 0.1 (T
i, Nb, V) (CNO) powder, (d) Ti2Mo:Cr=70%:29%:1% (by weight), C:N:0=0.60:0.25:0.1
(Ti, Mo.

Cr) (CNO) powder, using the powders (a) to (d) above, and further adding 2.5μ
m, and the W/T i (7)-E/l/ratio is 0.51
0.5, that is, 1/1, and Co powder and W powder with the same 1.0 μm, and these raw material powders were alloyed with the alloy composition shown in Table 4. 5) Blend an appropriate amount of this, and from the resulting blended powder, under the same conditions as in Example 1 [7) Invention Alloys 6 to 19
was manufactured.

Next, the above invention alloys 6 to 9 and the conventional alloy (P2O
) 4, chips for cutting tests were manufactured under the same conditions as in Example 1, and continuous cutting tests and interrupted cutting tests were conducted under the cutting conditions E and F shown in Table 5. Similarly, flank wear and crater wear were measured in the continuous cutting test, and the cutting edge loss ratio was measured in the interrupted cutting test.

The measurement results are shown in Table 6 along with the polished surface flow of the alloy structure.

As is clear from the results shown in Table 6, the alloy of the present invention exhibits superior wear resistance and impact resistance compared to the conventional alloy (P2O) 4 in heavy cutting with large feed and depth of cut.

Example 3 Raw material powders each having an average particle size of 1.5 μm were obtained, (a) C:N:0=0.65:0.20:
Ti (
CN0) powder, (b) C:0=0.85: 0.
Ti(Co) according to the invention with a molar ratio of 15
powder, (c) Ti(NO) powder according to the invention with a molar ratio of N:0 = 0.85: 0.15, (d) Ti:Ta = 80%: 20% (wt%), C:0
(Ti, TaXC0) powder according to the present invention with a molar ratio of =0.85:0.15, (e) C:
0=0.75: Ti(Co) powder with a molar ratio outside the range of this invention of 0.25, the above (a) to (
Using the powder of e) and obtaining the same 2.5 μm, W/
The molar ratio of Ti is 0.3510.65, or 7/13
(W, Ti)C powder with a diameter of 1.0 μm and a Co powder with a diameter of 1.0 μm were used, and these raw powders were blended in appropriate amounts to have the alloy composition shown in Table 7f, and from the resulting blended powder , the invention alloy 10~ under the same conditions as in Example 1.
No. 13 and Comparative Alloy 4 were produced.

Next, chips for cutting tests were manufactured from the above-mentioned invention alloys 10 to 13, comparative alloy 4, and conventional alloy (P2O) 5 under the same conditions as in Example 1, and the cutting conditions shown in Table 8 were made. A continuous cutting test and an interrupted cutting test were conducted using G and H.

The test results are shown in Table 9 (along with the condition of polishing streaks in the alloy structure).

As is clear from the results shown in Table 9, the alloy of the present invention exhibits superior wear resistance and impact resistance compared to Comparative Alloy 4 and Conventional Alloy 5.

Example 4 Raw material powder: (a) W:Ti=10%:90% (wt%), C:N:
(W, T i ) (CN
O) powder, (b) 1.0 μm TaC powder, (c) 1.5 μm NbC powder, (d) 2.5 μm VC powder, (e) 1.5 μm ZrC powder, (f ) Ti:Ta-90%:10% (by weight),
1.5 μm (Ti, Ta)C powder, (g) 1.
5 μm TiN powder, (h) 1.5 μm TaN powder, (i) C:N=0.7: 0.3. Ti(CN) powder with the same 1.5 μm molar ratio, (j) Ti:Mo=90%: 10% (weight), C:
N = 1.8 with a molar ratio of 0.7:0.3
(Ti, Mo) (CN) powder of μm, (k) N1 powder of i, 0 μm, (1) Co powder of 1.0 μm, using the powders of (a) to (1) above, and 2.5μ
m, and the W/T i 0)-E:)Ll ratio is 0.21
Using (W, Ti)C powder of 0.8, that is, 1/4, these raw material powders were blended in appropriate amounts to have the alloy composition shown in Table 10, and from this blended powder, Examples were prepared. Invention alloys 14 to 19 were produced under the same conditions as in Example 1.

Next, the above-mentioned alloys 14 to 19 of the present invention and the conventional alloy (P
From IO)6, chips for cutting tests were manufactured under the same conditions as in Example 1, and cutting tests were conducted under continuous cutting conditions B and intermittent cutting conditions 1]C shown in Table 2.

The test results are shown in Table 11.

Also in this Example 4, as shown in Table 11,
It is clear that the alloy of the present invention has superior wear and impact resistance compared to the conventional alloy (PLO grade) 6.

Example 5 In addition to the raw material powder used in Example 4, an average particle size of 0.8
Using W powder having a particle size of 1.5 μm, appropriate amounts of these raw material powders were blended to have the alloy composition shown in Table 12, and the alloys 20 to 23 of the present invention were prepared from this blended powder under the same conditions as in Example 1. Manufactured.

Next, the above-mentioned present invention alloys 20 to 23 and the conventional alloy (P
From 2O)7, chips for cutting tests were manufactured under the same conditions as in Example 1, and cutting tests were conducted under continuous cutting conditions G and intermittent cutting conditions H shown in Table 8E.

The test results are shown in Table 13.

As shown in Table 13, it is clear from Example 5 that the alloy of the present invention exhibits superior wear resistance and impact resistance compared to the conventional alloy (P2O) 71.

As mentioned above, the (W, Ti)C-based sintered hard alloy of the present invention has extremely excellent heat resistance, oxidation resistance, welding resistance,
Because it has both plastic deformation resistance and impact resistance,
It not only shows excellent cutting performance when applied to cutting high-hardness materials, high-speed cutting, and even heavy-duty cutting, but also hot drawing dies and hot rolling rolls that require heat resistance and impact resistance. It exhibits excellent properties even when used in
Furthermore, it has excellent corrosion resistance, making it suitable for manufacturing corrosion-resistant and wear-resistant parts, making it extremely versatile and highly effective in each field of use.

Claims (1)

[Claims] 1. Carbonates, nitrides, and carbonitrides of Ti, in which the molar ratio of oxygen to the total amount of oxygen and either or both of carbon and nitrogen is 0.2 or less. 4a, 5a, and 6 of the periodic table excluding Ti,
One or more of the group consisting of one or more carbonates, nitrides, and carbonitoxides of group a metals:
1 to 50%, one or more iron group metals: 5
~30%, tungsten/titanium carbide with a w/Ti molar ratio of 1/4 to 1/1 and unavoidable impurities; Carbide difference sintered hard alloy. 2 Ti carbonate, nitride oxide, and carbonitride oxide, and Ti, in which the molar ratio of oxygen to the total amount of oxygen and either or both of carbon and nitrogen is 0.2 or less; 4a, 5a, and 6 of the periodic table excluding Ti
One or more of the group consisting of carbonates, nitride oxides, and carbonitrides of one or more group a metals: 1 to 50%, one of the iron group metals tungsten/titanium carbide with a W/Ti molar ratio of 1/4 to 1/1 and unavoidable impurities: the remainder An oxygen-containing tungsten/titanium carbide differentially sintered hard alloy characterized by consisting of (more than % by volume). 3 Ti carbonate, nitride oxide, and carbonitride oxide, and Ti, in which the molar ratio of oxygen to the total amount of oxygen and either or both of carbon and nitrogen is 0.2 or less; 4a, 5a, and 6 of the periodic table excluding TI
One or more of the group consisting of carbonates, nitride oxides, and carbonitrides of one or more group a metals = 1 to 50%, one of the iron group metals Species or 2 or more types: 5 to 30%, 4a and 5 of the periodic table other than tungsten and titanium carbides
a, and one or more of carbides, nitrides, and carbonitrides of Group 6a metals: 1 to 50%, w, , with a molar ratio of Ti = 1/4 to 1/1 A tungsten/titanium carbide differentially sintered hard alloy containing oxygen, characterized in that the remainder (more than % by volume) consists of tungsten/titanium carbide and unavoidable impurities. 4 Ti carbonate, nitride oxide, and carbonitride oxide, and Ti, in which the molar ratio of oxygen to the total amount of oxygen and either or both of carbon and nitrogen is 0.2 or less; 4a, 5a, and 6 of the periodic table excluding Ti
One or more of the group consisting of carbonates, nitride oxides, and carbonitrides of one or more group a metals: 1 to 50%, one of the iron group metals Pillars or two or more types and one or more types of chromium group metals: 5 to 30%, 4a and 5 of the periodic table other than tungsten and titanium carbides
a, and one or more of carbides, nitrides, and carbonitrides of group 6a metals: 1 to 50%, and tungsten with a W/Ti molar ratio of 1/4 to 1/1. A tungsten/titanium carbide differentially sintered hard alloy containing oxygen, characterized in that the remainder (more than % by volume) consists of: titanium carbide and unavoidable impurities.