Blade member of cermet having surface reaction layer and process for producing same

A blade member for cutting tools comprises a cermet substrate having on a surface thereof a reaction layer. The reaction layer is composed of carbo-nitride of at least two metals in groups IV.sub.A, V.sub.A and VI.sub.A, the metals including Ti. The reaction layer may be composed of oxy-carbo-nitride of the above metals. The reaction layer may consist of inner and outer layers, the inner layer being composed of carbo-nitride of the above metals while the outer layer is composed of oxy-carbo-nitride of the above metals. The blade members with the reaction layer exhibits excellent toughness, wear resistance and thermoplastic deformation resistance. There is also disclosed a process for producing the above blade member.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to a blade member or insert of cermet for cutting 
tools having a wear-resistant and thermoplastic deformation-resistant 
reaction layer on a surface thereof, the blade member being suited for 
high speed cutting. 
2. Prior Art 
Conventionally, cermets, containing as hard phase-constituting components a 
major proportion of titanium carbide (TiC) and/or titanium nitride (TiN), 
have been extensively used to form blade members or inserts for high speed 
cutting tools such as a turning tool, since such hard cermets are superior 
in wear-resistance to cemented tungsten carbide. However, such cermet 
blade members have not met the requirement of very high speed cutting 
operation of above 200 m/minute. Therefore, in order to meet this 
requirement, hard ceramics containing a major proportion of aluminum oxide 
(Al.sub.2 O.sub.3) have been proposed to form a blade member capable of 
very high speed cutting. However, such ceramics contain no binder and 
therefore are inferior in toughness. As a result, the use of such ceramics 
blade members has been limited to high speed finish cutting. 
There has also been proposed and extensively used a high speed-cutting 
blade member made of cemented tungsten carbide and having on its surface a 
composite coating layer or layers composed of at least one material 
selected from the group consisting of TiC, TiN, titanium oxide (TiOx) and 
Al.sub.2 O.sub.3. Such coating layers are usually formed by a chemical 
vapor deposition process using reaction gas such as titanium 
tetrachloride, methane gas, hydrogen gas and nitrogen gas. Therefore, a 
deposition apparatus for forming such coating is large in size, and 
manufacturing costs of such surface-coated blade member are also 
increased. Further, the constituent parts of the deposition apparatus are 
susceptible to corrosion due to hydrochloric acid produced by chlorine gas 
generated upon decomposition of titanium tetrachloride. In addition, means 
for preventing leakage of such hydrochloric acid should be provided from a 
viewpoint of safety. Further, when the coating is formed on the blade 
member of cemented tungsten carbide by means of the chemical vapor 
deposition process, a decarburized .eta. phase is inevitably formed in its 
substrate immediately below the deposited coating. The presence of such a 
decarburized phase will lower the toughness of the blade member so that 
the blade member will not always have a satisfactory cutting performance. 
SUMMARY OF THE INVENTION 
It is therefore an object of this invention to provide a blade member of 
cermet having on its surface a reaction layer which exhibits excellent 
wear resistance and thermoplastic deformation resistance, whereby the 
blade member exhibits excellent cutting performance particularly when a 
high speed cutting operation is carried out. 
Another object is to provide a process for producing such a blade member. 
According to the present invention, there is provided a blade member for 
cutting tools which comprises a substrate of cermet containing, apart from 
impurities, 10 to 35% by volume of at least one binder metal selected from 
the group consisting of Fe, Co, Ni, Cr, Mo, W and Al, 5 to 40% by volume 
of at least one compound selected from the group consisting of carbides 
and nitrides of metals in groups IV.sub.A, V.sub.A and VI.sub.A of the 
periodic table as hard phase-constituting components, and balance titanium 
carbide and titanium nitride as main hard phase-constituting components 
(volume ratio of titanium nitride to titanium carbide plus titanium 
nitride is 0.2 to 0.6), said substrate having on a surface thereof a 
reaction layer composed of carbo-nitride of at least two metals in groups 
IV.sub.A, V.sub.A and VI.sub.A of the periodic table, said at least two 
metals including Ti, and said reaction layer having an average thickness 
of 0.5 to 15.0 .mu.m. 
According to a second aspect of the invention, a reaction layer on a cermet 
substrate of the above-mentioned components is composed of 
oxy-carbo-nitride of at least two metals in groups IV.sub.A, V.sub.A and 
VI.sub.A of the periodic table, said at least two metals including Ti. 
This reaction layer has an average thickness of 0.5 to 10.0 .mu.m. 
According to a third aspect of the invention, a reaction layer on a cermet 
substrate of the above-mentioned components consists of inner and outer 
layers. The inner layer is composed of carbo-nitride of at least two 
metals in groups IV.sub.A, V.sub.A and VI.sub.A of the periodic table, 
said at least two metals including Ti. The inner layer has an average 
thickness of 0.2 to 15.0 .mu.m. The outer layer is composed of 
oxy-carbo-nitride of at least two metals in groups IV.sub.A, V.sub.A and 
VI.sub.A of the periodic table, said at least two metals including Ti. The 
outer layer has an average thickness of 0.2 to 10.0 .mu.m. The combined 
average thicknesses of the inner and outer layers is 0.5 to 20.0 .mu.m. 
The above-mentioned reaction layers on the cermet substrates exhibit 
excellent wear resistance and thermoplastic deformation resistance when a 
cutting operation is carried out at a high cutting speed of 150 to 250 
m/min. using these blade members. 
The starting materials of the cermet substrate are in the form of powder. 
These powder materials are mixed together and then compacted into a 
densified solid body. This densified solid body is sintered under vacuum 
of not more than 10.sup.-1 torr to provide a cermet substrate. As a 
result, the cermet substrate has reduced nonmetallic content (mainly 
nitrogen content) due to denitridation during the sintering operation. 
In the case where the reaction layer, composed of carbo-nitride of metals 
and having an average thickness of 0.5 to 15.0 .mu.m, is formed in a 
surface of the cermet substrate, the cermet substrate is heated at 
temperatures of 1100.degree. to 1300.degree. C. in an atmosphere of 
N.sub.2. The reaction layer so formed has a high hardness and a high 
strength of bonding to the substrate body because there exists no clear 
linear boundary between the reaction layer and the cermet substrate. 
Further, no decarburized .eta. brittle phase is formed immediately below 
the reaction layer as is the case with the chemical deposited cemented 
carbide substrate. Further, the hard phase-constituting components react 
with N.sub.2 during the heating operation and are finely dispersed 
uniformly in the surface of the substrate so that the toughness of the 
resultant blade member is not lowered at all. Therefore, this blade member 
having the above-mentioned reaction layer is excellent in wear resistance 
and toughness. 
The reaction layer is formed through the reaction of the denitridated 
surface of the substrate with N.sub.2 during the heating treatment. This 
reaction is represented by the following formula: 
EQU (Ti, M)(CN).sub.1-a +(a/2)N.sub.2 .fwdarw.(Ti, M)(CN) 
wherein M is at least one metal selected from the group consisting of 
metals in groups IV.sub.A, V.sub.A and VI.sub.A of the periodic table 
except for Ti, and a is the amount of denitridation. The reaction layer 
should preferrably has the following composition formula: 
EQU (Ti, M) (CxNy) 
wherein 0.05.ltoreq.x.ltoreq.0.4 and 0.6.ltoreq.y.ltoreq.0.95 are provided 
in terms of molar ratio. 
In the reaction layer, concentrations of Ti and N become higher toward its 
surface, and concentrations of M and C become higher in a direction away 
from its surface. Thus, the reaction layer has continuous gradient of such 
concentration. And, the reaction layer has no free graphite or even if 
there exists any free graphite, the amount of free graphite is negligible 
since the surface of the substrate is denitridated during the sintering 
under vacuum of not more than 10.sup.-1 torr. As described above, the 
reaction layer composed of carbo-nitride of metals has an average 
thickness of 0.5 to 15.0 .mu.m. If the average thickness is less than 0.5 
.mu.m, the reaction layer does not possess desired wear resistance and 
thermoplastic deformation resistance. On the other hand, if the average 
thickness exceeds 15 .mu.m, the resultant blade member has a reduced 
toughness. 
In the case where the reaction layer, composed of oxy-carbo-nitride of 
metals and having an average thickness of 0.5 to 10.0 .mu.m, is formed in 
a surface of the cermet substrate, the substrate is heated at temperatures 
of 1100.degree. to 1300.degree. C. either in an atmosphere of one or both 
of CO and CO.sub.2 or in an atmosphere of N.sub.2 and one or both of CO 
and CO.sub.2. 
This reaction layer is formed through the reaction of the denitridated 
surface of the substrate with either CO or CO plus N.sub.2 (CO.sub.2 
reacts with C in a reaction chamber to form CO: CO.sub.2 +C.fwdarw.2CO). 
The reaction layer composed of oxy-carbo-nitride of metals is formed 
either by the following reaction: 
EQU (Ti, M)(CN).sub.1-1 +a(CO).fwdarw.(Ti, M)(CNO) 
wherein M is at least one metal selected from the group consisting of 
metals in groups IV.sub.A, V.sub.A and VI.sub.A of the periodic table 
except for Ti, and a is the amount of denitridation or by the following 
reaction: 
EQU (Ti, M)(CN).sub.1-a' +(b'/2)N.sub.2 +c'(CO).fwdarw.(Ti, M)(CNO) 
wherein a' is the amount of denitridation (a'=b'+c'). The reaction layer 
should preferrably has the following composition formula: 
EQU (Ti, M) (CxNyOz) 
wherein x is 0.2 to 0.7, y is 0.1 to 0.7 and z is 0.05 to 0.4 (molar 
ratio). Although the rate of formation of this reaction layer composed of 
oxy-carbo-nitride of metals is lower than that of the reaction layer of 
carbo-nitride of metals, the former is higher in wear resistance than the 
latter if they have the same thickness. Further, the hard 
phase-constituting components react with CO during the heating operation 
and are finely dispersed uniformly in the surface of the substrate so that 
the toughness of the resultant blade member is not lowered at all. 
Therefore, this blade member having the above-mentioned reaction layer 
exhibits excellent wear resistance and toughness. 
In this reaction layer, concentrations of Ti, C and O become higher toward 
its surface, and concentrations of M and N become higher in a direction 
away from its surface. Thus, the reaction layer has continuous gradient of 
such concentration. 
As described above, the reaction layer composed of oxy-carbo-nitride of 
metals has an average thickness of 0.5 to 10.0 .mu.m. If the average 
thickness is less than 0.5 .mu.m, the reaction layer does not possess 
desired wear resistance and thermoplastic deformation resistance. On the 
other hand, if the average thickness exceeds 10 .mu.m, the resultant blade 
member has a reduced toughness. 
In the case where the reaction layer, consisting of the inner layer of 
carbo-nitride of metals and the outer layer of oxy-carbo-nitride of 
metals, is formed in a surface of the cermet substrate, a base reaction 
layer composed of carbo-nitride of metals is first formed according to the 
procedure described above for the reaction layer of carbo-nitride of 
metals. In this case, however, the base reaction layer has an average 
thickness of 0.5 to 20.0 .mu.m. The inner portion of the base reaction 
layer serves as the above-mentioned inner layer. Then, if there exists no 
free carbon in the base reaction surface of the cermet substrate, the 
substrate is heated at 1100.degree. to 1300.degree. C. in an atmosphere of 
CO so that the outer layer of oxy-carbo-nitride of metals is formed in the 
surface of the base reaction surface. Alternatively, if there exists any 
free carbon in the base reaction layer, the substrate is heated at 
1100.degree. to 1300.degree. C. either in an atmosphere of CO.sub.2 or in 
an atmosphere of CO.sub.2 and CO to form the outer layer of 
oxy-carbo-nitride of metals in the surface of the base reaction surface. 
In either case, as described above, the outer layer has an average 
thickness of 0.2 to 10.0 .mu.m, and the inner layer of carbo-nitride of 
metals has an average thickness of 0.2 to 15.0 .mu.m. But, the combined 
average thickness of the inner and outer layers should be 0.5 to 20.0 
.mu.m. If the average thickness of each of the inner and outer layers is 
less than 0.2 .mu.m, and if their combined average thicknesses is less 
than 0.5 .mu.m, the reaction layer composed of the inner and outer layers 
does not possess desired wear resistance and thermoplastic deformation 
resistance. On the other hand, if the average thicknesses of the outer and 
inner layers exceed 10.0 .mu.m and 15.0 .mu.m, respectively, and if their 
combined average thicknesses exceed 20.0 .mu.m, the resultant blade member 
has a reduced toughness. 
The provision of the inner layer composed of carbo-nitride of metals and 
the outer layer composed of oxy-carbo-nitride of metals serves to further 
enhance the wear resistance and thermoplastic deformation resistance of 
the overall reaction layer. 
The content of the binder metal or metals in the cermet substrate is 10 to 
35% by volume. The binder metal or metals serve to enhance the toughness 
of the cermet substrate, and if the content of the binder metal or metals 
is less than 10% by volume, a desired toughness of the cermet substrate is 
not achieved. On the other hand, if the content exceeds 35% by volume, 
wear resistance of the cermet substrate is lowered. 
The carbides and nitrides of metals in group IV.sub.A, V.sub.A and VI.sub.A 
serve to improve plastic deformation resistance. Further, carbides of Mo 
and W serve to enhance the toughness of the cermet substrate. The content 
of the metal carbide and/or nitride is 5 to 40% by volume. If its content 
is less than 5% by volume, the desired effects can not be achieved. If the 
content exceeds 40% by volume, the wear resistance of the cermet substrate 
is lowered, and the reaction layer on the surface of the substrate fails 
to exhibit excellent wear resistance. 
The balance titanium carbide and titanium nitride also serve as main hard 
phase-constituting components of the cermet substrate. The volume ratio of 
titanium nitride to titanium carbide plus titanium nitride should be 0.2 
to 0.6. If the volume ratio is less than 0.2, the content of titanium 
nitride is correspondingly low so that the amount of denitridation of the 
substrate during the vacuum sintering operation is too small. As a result, 
a considerable amount of free carbon will exist in the resultant reaction 
surface layer formed through the subsequent heating treatment. This would 
adversely affect the wear resistance of the reaction layer and the 
toughness of the cermet substrate. On the other hand, if the volume ratio 
exceeds 0.6, the content of titanium nitride is correspondingly increased 
so that the amount of denitridation of the surface layer of the substrate 
during the vacuum sintering operation is too large. As a result, the 
resultant blade member has a roughened surface so that its accuracy is 
adversely affected. In addition, the wear resistance of the reaction 
surface and the toughness of the blade member are lowered. 
The compacted body of the powder materials should be sintered under vacuum 
of not more than 10.sup.-1 torr to form the cermet substrate. If the 
sintering is carried out under vacuum of more than 10.sup.-1 torr, the 
nonmetallic content (mainly, the nitrogen content) of the cermet substrate 
is not sufficiently reduced. As a result, the reaction layer having 
desired properties can not be formed in the surface of the cermet 
substrate at the subsequent heating treatment. 
The heat treatment of the cermet substrate is carried out at temperatures 
of 1100.degree. to 1300.degree. C. If the temperature is less than 
1100.degree. C., the speed of formation of the reaction layer is lowered 
and therefore the production rate of the blade member is low. On the other 
hand, if the temperature is more than 1300.degree. C., the reaction 
surface is so roughened that accuracy of the blade member is adversely 
affected. 
The impurities contained in this cermet substrate include O.sub.2, B and 
Si. If the content of the impurities is less than 2% by volume, they will 
not affect the intended properties of the cermet substrate at all.

DESCRIPTION OF THE INVENTION 
The invention will now be illustrated by the following Examples: 
The following Examples 1 to 3 illustrates blade members having on a surface 
a reaction layer composed of carbo-nitride of metals. 
EXAMPLE 1 
Powders of TiC (average particle size: 1.5 .mu.m), TiN (1.0 .mu.m), TaC 
(1.0 .mu.m), WC (1.2 .mu.m), Mo (0.8 .mu.m), Ni (2.5 .mu.m) and Co (1.2 
.mu.m) were prepared as starting materials. The starting materials were 
mixed together in predetermined amounts to provide a mixture. Then, the 
mixture was compacted into a densified solid body. Then, the densified 
body was sintered at temperature of 1450.degree. C. for 1.5 hours under 
vacuum of 10.sup.-2 torr to form a cermet substrate. The cermet substrate 
consisted of 45% by volume TiC, 25% TiN, 5% TaC, 5% WC, 10% Mo, 4% Ni and 
6% Co (the ratio of TiN to TiC plus TiN was 0.36). The cermet substrate 
was then ground into a shape conforming to JIS.multidot.SNP432. Cermet 
substrates prepared in this manner were subjected to heat treatment under 
conditions shown in Tabe 1 to produce blade members 1 to 7 of this 
invention. The composition of each reaction layer shown in Table 1 was 
that of the central portion of the reaction layer. 
For comparison purposes, cermet substrates prepared according to the above 
procedure were subjected to heat treatment at temperatures above the upper 
temperature limit of this invention, i.e., 1300.degree. C., to produce 
comparison blade members 1 and 2. Also, there were provided comparison 
blade member 3 of cermet containing TiC, Ni and Mo and WC-based comparison 
blade member 4 having on a surface 6 .mu.m thick coating composed of a 
layer of TiC and layer of Al.sub.2 O.sub.3. The comparison blade members 3 
and 4 were commercially available. 
The blade members 1 to 7 of this invention and the comparison blade members 
1 to 4 were each attached to a holder and subjected to a continuous 
cutting test to determine wear resistance. The conditions for this 
continuous cutting test were as follows: 
Workpiece: a bar of steel (JIS.multidot.SNCM-8; AISI.multidot.4340; 
Hardness: HB240) 
Cutting speed: 250 m/minute 
Feed rate: 0.30 mm/revolution 
Depth of cut: 1.5 mm 
Time: 10 minutes 
After this continuous cutting test, the flank wear and the crater wear of 
each blade member were observed. The results obtained are shown in Table 
1. 
Also, the blade members 1 to 7 of this invention and the comparison blade 
members 1 to 4 were subjected to an intermittent cutting test to determine 
toughness. In this intermittent test, two workpieces in the form of block 
were fixedly secured to a turning support member. A tool holder holding 
the blade member was located adjacent to the support member so that during 
the turning of the support member, the outer surfaces of the two 
workpieces were intermittently brought into cutting engagement with the 
blade member. In this test, it was determined how many blade members of 
the same construction out of ten were subjected to chipping. The 
conditions for this intermittent cutting test were as follows: 
Workpiece: a block of steel (JIS.multidot.SNCM-8; Hardness: HB280) 
Cutting speed: 140 m/minute 
Feed rate: 0.3 mm/revolution 
Depth of cut: 2 mm 
Time: 3 minutes 
The results of this intermittent cutting test are shown in Table 1. 
TABLE 1 
__________________________________________________________________________ 
Intermittent 
Heat treatment Continuous cutting 
cutting test 
Heat Reaction layer test Number of chipped 
Kind of 
Pressure 
tempera- 
Composition of carbo-nitride of metals: 
Average 
Flank 
Crater 
blade members/ 
blade of N.sub.2 
ture Time 
(Ti, M) (CxNy) thickness 
wear wear number of tested 
member 
(torr) 
(.degree.C.) 
(h) 
(molar ratio) (.mu.m) 
(mm) (.mu.m) 
members 
__________________________________________________________________________ 
Blade 
members of 
this 
invention 
1 600 1240 10 (Ti.sub.0.80 Ta.sub.0.06 W.sub.0.03 Mo.sub.0.11)--(C.su 
b.0.18 N.sub.0.82) 3.5 0.19 25 1/10 
2 550 1250 8 (TI.sub.0.80 Ta.sub.0.06 W.sub.0.03 Mo.sub.0.11)--(C.su 
b.0.15 N.sub.0.83) 4.0 0.16 20 2/10 
3 500 1260 7 (Ti.sub.0.81 Ta.sub.0.06 W.sub.0.03 Mo.sub.0.10)--(C.su 
b.0.16 N.sub.0.84) 4.0 0.16 20 2/10 
4 450 1270 6 (Ti.sub.0.81 Ta.sub.0.06 W.sub.0.03 Mo.sub.0.10)--(C.su 
b.0.17 N.sub.0.83) 4.0 0.16 20 2/10 
5 400 1280 8 (Ti.sub.0.82 Ta.sub.0.05 W.sub.0.03 Mo.sub.0.10)--(C.su 
b.0.20 N.sub.0.80) 6.0 0.14 15 3/10 
6 450 1290 13 (Ti.sub.0.84 Ta.sub.0.05 W.sub.0.02 Mo.sub.0.09)--(C.su 
b.0.25 N.sub.0.75) 10.0 0.17 10 4/10 
7 550 1300 18 (Ti.sub.0.86 Ta.sub.0.04 W.sub.0.02 Mo.sub.0.08)--(C.su 
b.0.30 N.sub.0.70) 15.0 0.20 10 6/10 
Compari- 
son blade 
members 
1 550 1320* 
18 (Ti.sub.0.87 Ta.sub.0.04 W.sub.0.02 Mo.sub.0.07)--(C.su 
b.0.41 N.sub.0.59) 17.0* 
0.28 10 10/10 
2 550 1310* 
10 (Ti.sub.0.87 Ta.sub.0.04 W.sub.0.02 Mo.sub.0.07)--(C.su 
b.0.36 N.sub.0.64) 10.0 0.23 10 8/10 
3 -- 0.37 50 10/10 
Plastic deformation 
developed 
4 -- 0.31 100 4/10 
Plastic deformation 
developed 
__________________________________________________________________________ 
*not falling within the range of this invention 
As seen from Table 1, the blade members 1 to 7 of this invention exhibited 
excellent toughness, excellent wear resistance and excellent thermoplastic 
deformation resistance. On the other hand, the comparison blade members 1 
to 4 were extremely inferior in such properties. 
EXAMPLE 2 
Powder materials described in Example 1 and powders of NbC (1.0 .mu.m), ZrC 
(1.5 .mu.m), Mo.sub.2 C (1.2 .mu.m) and TaN (1.0 .mu.m) were selectively 
used as starting powder materials. The powder materials were mixed 
together in ratios shown in Table 2 to provide various mixtures. Each 
mixture was pressed into a densified solid body having a shape conforming 
to JIS.multidot.SNMG 432. Then, the densified solid bodies were sintered 
at temperature of 1450.degree. C. for 1.5 hours under vacuum shown in 
Table 2 to form cermet substrates 8a to 14a of this invention and 
comparative cermet substrates 5a to 8a. The cermet substrates were 
substantially identical in composition to their respective mixtures. Then, 
the cermet substrates 8a to 14a of this invention were subjected to heat 
treatment under conditions shown in Table 3 to produce blade members 8 to 
14 of this invention. Also, the comparison substrates 5a to 8a were 
subjected to heat treatment to produce comparison blade members 5 to 8. 
The substrates were subjected to the heat treatment in the above sintering 
furnace. Each comparison substrate had component contents not falling 
within this invention as indicated by mark * in Table 2. The comparison 
blade members 5 and 6 had free carbon in their reaction layer and at 
portions immediately adjacent thereto. The comparison blade member 7 had 
an extremely roughened surface. 
The blade members 8 to 14 of this invention and the comparison blade 
members 5 to 8 were subjected to a continuous cutting test. The conditions 
for this continuous cutting test were as follows: 
Workpiece: a bar of steel (JIS.multidot.SNCM-8; Hardness: HB240) 
Cutting speed: 200 m/minute 
Feed rate: 0.36 mm/revolution 
Depth of cut: 1.5 mm 
Time: 10 minutes 
An intermittent cutting test was also carried out under the following 
cutting conditions: 
Workpiece: a block of steel (JIS.multidot.SNCM-8; Hardness: HB280) 
Cutting speed: 120 m/minute 
Feed rate: 0.3 mm/revolution 
Depth of cut: 2 mm 
Time: 3 minutes 
The results of the continuous and intermittent cutting tests are shown in 
Table 3. 
TABLE 2 
__________________________________________________________________________ 
Composition (volume %) 
Kind of blade member 
Hard phase constituting components TiCTiNTaCNbCZrCWCMo.sub.2 
CTaN Binder components MoNiCo 
##STR1## 
Sintering vacuum (torr) 
__________________________________________________________________________ 
Substrates of this 
substrates 
8a 50 13 -- -- -- 5 -- -- 20 4 8 0.21 10.sup.-2 
9a 49 22 -- -- -- 5 -- -- 12 4 8 0.31 
10a 42 29 -- -- -- 5 -- -- 12 4 8 0.41 
11a 35 36 -- -- -- 5 12 -- -- 4 8 0.51 10.sup.-1 
12a 29 42 -- -- -- 5 12 -- -- 4 8 0.59 
13a 31 20 10 5 -- 10 12 -- -- 4 8 0.39 
14a 41 27 -- -- 1 5 -- 2 12 4 8 0.40 10.sup.-2 
Comparison 
substrate 
8a 71* 
--* 
-- -- -- 5 -- -- 12 4 8 0* 
6a 61* 
10* 
-- -- -- 5 -- -- 12 4 8 0.14* 
7a 24* 
47* 
-- -- -- 5 12 -- -- 4 8 0.66* 10.sup.-1 
8a 70 18 --* 
--* 
--* 
--* 
--* --* 
-- 4 8 0.20 10.sup.-2 
__________________________________________________________________________ 
*not falling within this invention 
TABLE 3 
__________________________________________________________________________ 
Continuous 
Intermittent 
Heat treatment cutting cutting test 
Heat Reaction layer test Number of chipped 
Kind of 
Pressure 
tempera- 
Composition of carbo-nitride metals: 
Average 
Flank 
Crater 
blade members/ 
blade of N.sub.2 
ture Time 
(Ti, M) (CxNy) thickness 
wear 
wear 
number of tested 
member 
(torr) 
(.degree.C.) 
(h) 
(molar ratio) (.mu.m) 
(mm) 
(.mu.m) 
members 
__________________________________________________________________________ 
Blade 
members of 
this 
invention 
8 500 1280 6 (Ti.sub.0.77 W.sub.0.04 Mo.sub.0.19)--(C.sub.0.23 
N.sub.0.77) 4.0 0.17 
20 3/10 
9 (Ti.sub.0.84 W.sub.0.03 Mo.sub.0.13)--(C.sub.0.20 
N.sub.0.80) 4.5 0.15 
15 3/10 
10 (Ti.sub.0.86 W.sub.0.03 Mo.sub.0.11)--(C.sub.0.15 
N.sub.0.85) 4.5 0.13 
15 2/10 
11 300 (Ti.sub.0.88 W.sub.0.03 Mo.sub.0.09)--(C.sub.0.12 
N.sub.0.88) 4.5 0.15 
15 2/10 
12 (Ti.sub.0.89 W.sub.0.03 Mo.sub. 0.08)--(C.sub.0.08 
N.sub.0.92) 4.5 0.20 
10 4/10 
13 500 (Ti.sub.0.65 Ta.sub.0.14 Nb.sub.0.06 W.sub.0.07 
Mo.sub.0.08)--(C.sub.0.19 N.sub.0.81) 
4.0 0.19 
25 1/10 
14 (Ti.sub.0.83 Ta.sub.0.04 W.sub.0.03 Mo.sub.0.10)--(C.su 
b.0.18 N.sub.0.82) 4.5 0.17 
20 2/10 
Compari- 
son blade 
member 
5 (Ti.sub.0.83 W.sub.0.03 Mo.sub.0.14)--(C.sub.0.56 
N.sub.0.44) 3.5 0.35 
50 10/10 
6 (Ti.sub.0.84 W.sub.0.03 Mo.sub.0.13)--(C.sub.0.30 
N.sub.0.70) 4.0 0.30 
30 7/10 
7 300 (Ti.sub.0.89 W.sub.0.03 Mo.sub.0.08)--(C.sub.0.05 
N.sub.0.95) 4.5 0.37 
20 9/10 
8 500 Ti--(C.sub.0.22 N.sub.0.78) 
4.5 0.30 
25 10/10 
__________________________________________________________________________ 
As can be seen from Table 3, the blade members 8 to 14 of this invention 
exhibited excellent wear resistance and excellent toughness and achieved 
an excellent cutting performance. On the other hand, the comparison blade 
members 5 to 8, whose substrates had the compositions not falling within 
the range of this invention, were very inferior in wear resistance and 
toughness and exhibited a poor cutting performance. 
EXAMPLE 3 
Cermet substrates, composed of 26.5% by volume TiC, 20% TiN, 10% TaC, 15% 
WC, 10% Mo, 5.5% Ni, 11% Co and 2% Al (the volume ratio of TiN to TiC plus 
TiN: 0.43), were prepared according to the procedure of Example 1. The 
cermet substrates were subjected to heat treatment under conditions shown 
in Table 4 to produce blade members 15 to 19 of this invention and 
comparison blade member 9. The cermet substrate not subjected to heat 
treatment was used as comparison blade member 10. Also, there were 
provided WC-based comparison blade member 11 (JIS.multidot.P10) and 
comparison WC-based blade member 12 having on a surface 7 .mu.m thick 
coating composed of TiC layer and TiN layer. 
The blade members 15 to 19 of this invention and the comparison blade 
members 9 to 12 were subjected to a continuous cutting test. The 
conditions for this continuous cutting test were as follows: 
Workpiece: a bar of steel (JIS.multidot.SNCM-8; Hardness: HB240) 
Cutting speed: 160 m/minute 
Feed rate: 0.44 mm/revolution 
Depth of cut: 1.5 mm 
Time: 15 minutes 
An intermittent cutting test was also carried out under the following 
cutting conditions: 
Workpiece: a block of steel (JIS.multidot.SNCM-8; Hardness: HB280) 
Cutting speed: 100 m/minute 
Feed rate: 0.335 mm/revolution 
Depth of cut: 2 mm 
Time: 3 minutes 
The results of the continuous and intermittent cutting tests are shown in 
Table 4. 
TABLE 4 
__________________________________________________________________________ 
Continuous 
Intermittent 
cutting test 
Heat treatment cutting Number 
Heat Reaction layer test of chipped 
Pressure 
tempera- 
Composition of carbo-nitride metals: 
Average 
Flank 
Crater 
blade members/ 
Kind of of N.sub.2 
ture Time 
(Ti, M) (CxNy) thickness 
wear 
wear 
number of tested 
blade member 
(torr) 
(.degree.C.) 
(h) 
(molar ratio) (.mu.m) 
(mm) 
(.mu.m) 
members 
__________________________________________________________________________ 
Blade members of 
this invention 
15 200 1100 16 Not measurable 0.5 0.30 
50 1/10 
16 1150 (Ti.sub.0.67 Ta.sub.0.13 W.sub.0.09 Mo.sub.0.11)--(C 
.sub.0.30 N.sub.0.70) 
1.0 0.21 
40 1/10 
17 300 1200 10 (Ti.sub.0.68 Ta.sub.0.13 W.sub.0.09 Mo.sub.0.10)--(C 
.sub.0.25 N.sub.0.75) 
2.0 0.19 
30 1/10 
18 400 1260 6 (Ti.sub.0.72 Ta.sub.0.12 W.sub.0.07 Mo.sub.0.09)--(C 
.sub. 0.15 N.sub.0.85) 
3.0 0.16 
20 1/10 
19 500 1280 7 (Ti.sub.0.72 Ta.sub.0.12 W.sub.0.07 Mo.sub.0.09)--(C 
.sub.0.16 N.sub.0.84) 
4.0 0.15 
20 2/10 
Comparison 
blade members 
9 200 1050* 
16 Not measurable 0.3* 
0.39 
65 1/10 
10 -- -- 0.47 
80 2/10 
11 -- 0.53 
150 
4/10 
12 -- 0.35 
60 3/10 
__________________________________________________________________________ 
*not falling within the range of this invention 
As can be seen from Table 4, the blade members 15 to 19 of this invention 
exhibited excellent wear resistance and excellent toughness in comparison 
with the comparison blade members 11 and 12. The reaction layer of the 
comparison blade member 9 had an average thickness of 0.3 .mu.m which is 
below the lower limit of the thickness range of this invention. The 
comparison blade member 10 had no reaction surface layer. Therefore, the 
two comparison blade members 9 and 10 were substantially equal in 
toughness to the blade members of this invention but were inferior in wear 
resistance. 
The following Examples 4 to 6 illustrate blade members having on a surface 
a reaction layer composed of oxy-carbo-nitride of metals. 
EXAMPLE 4 
Cermet substrates were prepared according to the procedure of Example 1 
using the same powder materials, the cermet substrates having the same 
composition as the cermet substrates of Example 1. The cermet substrates 
were then ground into a shape conforming to JIS.multidot.SNP432. The 
cermet substrates were then subjected to heat treatment in an atmosphere 
of CO.sub.2 or in an atmosphere of CO.sub.2 and N.sub.2 under conditions 
shown in Table 5 to produce blade members 20 to 26 of this invention and 
comparison blade members 13 and 14. The comparison blade members 13 and 14 
were produced under the conditions not falling within the range of this 
invention, as shown in Table 5. Also, there were provided comparison blade 
member 15 of cermet containing TiC, Ni and Mo and WC-based comparison 
blade member 16 having on a surface 6 .mu.m thick coating composed of a 
layer of TiC and a layer of Al.sub.2 O.sub.3. 
The blade members 20 to 26 of this invention and the comparison blade 
members 13 to 16 were subjected to a continuous cutting test and an 
intermittent cutting test. The conditions for this continuous cutting test 
were as follows: 
Workpiece: a bar of steel (JIS.multidot.SNCM-8; Hardness: HB220) 
Cutting speed: 250 m/minute 
Feed rate: 0.36 mm/revolution 
Depth of cut: 1.5 mm 
Time: 10 minutes 
The conditions for the intermittent cutting test were as follows: 
Workpiece: a block of steel (JIS.multidot.SNCM-8; Hardness: HB280) 
Cutting speed: 140 m/minute 
Feed rate: 0.3 mm/revolution 
Depth of cut: 2 mm 
Time: 3 minutes 
The results of these two continuous and intermittent cutting tests are 
shown in Table 5. 
TABLE 5 
__________________________________________________________________________ 
Inter- 
mittent 
cutting 
test 
Number 
of 
chipped 
blade 
mem- 
Heat treatment Continuous 
bers/ng 
Pres- Pres- 
Heat Reaction layer test number 
Kind of 
sure 
sure 
tempera- 
Composition of oxy-carbo-nitride of 
Average 
Flank 
Crater 
of tested 
blade of CO.sub.2 
of N.sub.2 
ture Time 
metals: (Ti, M) (CxNyOz) 
thickness 
wear wear blade 
member 
(torr) 
(torr) 
(.degree.C.) 
(h) 
(molar ratio) (.mu.m) 
(mm) (.mu.m) 
members 
__________________________________________________________________________ 
Blade 
members of 
this 
invention 
20 350 -- 1250 12 (Ti.sub.0.81 Ta.sub.0.06 W.sub.0.03 Mo.sub.0.10)--(C 
.sub.0.60 N.sub.0.20 O.sub.0.20) 
1.5 0.18 25 1/10 
21 300 -- 1260 10 (Ti.sub.0.81 Ta.sub.0.06 W.sub.0.03 Mo.sub.0.10)--(C 
.sub.0.60 N.sub.0.20 O.sub.0.20) 
2.0 0.16 20 2/10 
22 250 -- 1270 8 (Ti.sub.0.82 Ta.sub.0.05 W.sub.0.03 Mo.sub.0.10)--(C 
.sub.0.58 N.sub.0.20 O.sub.0.22) 
2.0 0.15 20 2/10 
23 200 -- 1280 6 (Ti.sub.0.82 Ta.sub.0.05 W.sub.0.03 Mo.sub.0.10)--(C 
.sub.0.55 N.sub.0.20 O.sub.0.25) 
2.0 0.15 20 2/10 
24 100 200 1280 8 (Ti.sub.0.83 Ta.sub.0.05 W.sub.0.03 Mo.sub.0.09)--(C 
.sub.0.30 N.sub.0.55 O.sub.0.15) 
4.5 0.13 15 3/10 
25 100 300 1290 15 (Ti.sub.0.85 Ta.sub.0.04 W.sub.0.03 Mo.sub.0.08)--(C 
.sub.0.17 N.sub.0.65 O.sub.0.18) 
7.5 0.15 10 4/10 
26 150 400 1300 20 (Ti.sub.0.87 Ta.sub.0.04 W.sub.0.02 Mo.sub.0.07)--(C 
.sub.0.10 N.sub.0.70 O.sub.0.20) 
10.0 0.16 10 5/10 
Compari- 
son blade 
members 
13 150 400 1320* 
20 (Ti.sub.0.88 Ta.sub.0.04 W.sub.0.02 Mo.sub.0.06)--(C 
.sub.0.05 N.sub.0.75 O.sub.0.20) 
12.0* 
0.20 10 10/10 
14 --* --* 1280 6 -- -- 0.42 50 2/10 
Plastic Deformation 
15 -- 0.39 55 10/10 
Plastic Deformation 
16 -- 0.36 100 4/10 
Plastic 
__________________________________________________________________________ 
Deformation 
*not falling within this invention 
As can be seen from Table 5, the blade members 20 to 26 exhibited excellent 
toughness, excellent wear resistance and excellent thermoplastic 
deformation resistance. The comparison blade members 15 and 16 were 
extremely inferior in these properties. The comparison blade member 13 was 
extremely inferior in toughness, and the comparison blade member 14 were 
extremely inferior in wear resistance and thermoplastic deformation 
resistance. 
EXAMPLE 5 
The same powder materials described in Example 2 were mixed together in 
ratios shown in Table 2 to provide various mixtures. Cermet substrates 8a 
to 14a and comparison substrates 5a to 8a were produced from these 
mixtures according to the same procedure of Example 2. The cermet 
substrates 8a to 14a of this invention were subjected to heat treatment 
under conditions shown in Table 6 to produce blade members 27 to 33 of 
this invention, respectively. Also, the comparison cermet substrates 5a to 
8a were subjected to heat treatment under conditions shown in Table 6 to 
produce comparison blade members 17 to 20, respectively. The comparison 
blade members 17 and 18 had free carbon in their reaction layers and at 
portions immediately adjacent thereto. The comparison blade member 19 had 
an extremely roughened surface. 
The blade members 27 to 33 of this invention and the comparison blade 
members 17 to 20 were subjected to a continuous cutting test and an 
intermittent cutting test. 
The conditions for this continuous cutting test were as follows: 
Workpiece: a bar of steel (JIS.multidot.SNCM-8; Hardness: HB260) 
Cutting speed: 200 m/minute 
Feed rate: 0.36 mm/revolution 
Depth of cut: 1.5 mm 
Time: 10 minutes 
The conditions for the intermittent cutting test were as follows: 
Workpiece: a block of steel (JIS.multidot.SNCM-8; Hardness: HB280) 
Cutting speed: 120 m/minute 
Feed rate: 0.3 mm 
Depth of cut: 2 mm 
Time: 3 minutes 
The results of the continuous and intermittent cutting tests are shown in 
Table 6. 
TABLE 6 
__________________________________________________________________________ 
Inter- 
mittent 
cutting 
test 
Number 
of 
chipped 
Heat treatment Continuous 
bladeng 
Pres- Pres- 
Heat Reaction layer test mem- 
Kind of 
sure 
sure 
tempera- 
Composition of oxy-carbo-nitride of 
Average 
Flank 
Crater 
bers/ 
blade of CO.sub.2 
of N.sub.2 
ture Time 
metals: (Ti, M) (CxNyOz) 
thickness 
wear wear tested 
member 
(torr) 
(torr) 
(.degree.C.) 
(h) 
(molar ratio) (.mu.m) 
(mm) (.mu.m) 
members 
__________________________________________________________________________ 
Blade 
members of 
this 
invention 
27 200 -- 1280 7 (Ti.sub.0.77 W.sub.0.04 Mo.sub.0.18)--(C.sub.0.62 
N.sub.0.13 O.sub.0.25) 
1.5 0.16 25 3/10 
28 (Ti.sub.0.85 W.sub.0.03 Mo.sub.0.12)--(C.sub.0.58 
N.sub.0.17 O.sub.0.25) 
2.0 0.14 20 2/10 
29 (Ti.sub.0.86 W.sub.0.03 Mo.sub.0.11)-- (C.sub.0.53 
N.sub.0.22 O.sub.0.25) 
2.0 0.13 15 1/10 
30 100 -- (Ti.sub.0.88 W.sub.0.03 Mo.sub.0.09)--(C.sub.0.48 
N.sub.0.27 O.sub.0.25) 
2.0 0.15 15 2/10 
31 (Ti.sub.0.89 W.sub.0.03 Mo.sub.0.08)--(C.sub.0.44 
N.sub.0.30 O.sub.0.26) 
2.5 0.19 10 3/10 
32 100 200 (Ti.sub.0.66 Ta.sub.0.13 Nb.sub.0.06 W.sub.0.07 
Mo.sub.0.08)-- 4.0 0.18 20 1/10 
(C.sub.0.88 N.sub.0.60 O.sub.0.12) 
33 100 200 (Ti.sub.0.84 Ta.sub.0.03 W.sub.0.03 Mo.sub.0.10)--(C 
.sub.0.28 N.sub.0.55 O.sub.0.17) 
4.0 0.16 15 2/10 
Compari- 
son blade 
members 
17 200 -- (Ti.sub.0.85 W.sub.0.03 Mo.sub.0.12)--(C.sub.0.88 
O.sub.0.12) 0.8 0.33 50 10/10 
18 (Ti.sub.0.85 W.sub.0.03 Mo.sub.0.12)--(C.sub.0.71 
N.sub.0.09 O.sub.0.20) 
1.0 0.29 35 6/10 
19 100 -- (Ti.sub.0.89 W.sub.0.03 Mo.sub.0.08)--(C.sub.0.37 
N.sub.0.33 O.sub.0.30) 
2.5 0.37 15 9/10 
20 200 -- Ti--(C.sub.0.60 N.sub.0.12 O.sub.0.28) 
2.0 0.28 30 10/10 
__________________________________________________________________________ 
As can be seen from Table 6, the blade members 27 to 33 of this invention 
exhibited excellent wear resistance and excellent toughness and achieved a 
good cutting performance. On the other hand, the comparison blade members 
17 to 20 whose substrates had the compositions not falling within the 
range of this invention, were very inferior in wear resistance and 
toughness and exhibited a poor cutting performance. 
EXAMPLE 6 
Cermet substrates, composed of 26.5% by volume TiC, 20% TiN, 10% TaC, 15% 
WC, 10% Mo, 5.5% Ni, 11% Co and 2% Al (the volume ratio of TiN to TiC plus 
TiN: 0.43), were prepared according to the procedure of Example 1. The 
cermet substrates were subjected to heat treatment under conditions shown 
in Table 7 to produce blade members 34 to 38 of this invention and 
comparison blade member 21. The cermet substrate not subjected to heat 
treatment was used as comparison blade member 22. Also, there were 
provided WC-based comparison blade member 23 (JIS.multidot.P10) and 
comparison WC-based blade member 24 having on a surface 7 .mu.m thick 
coating composed of TiC layer and TiN layer. 
The blade members 34 to 38 of this invention and the comparison blade 
members 21 to 24 were subjected to a continuous cutting test. The 
conditions for this continuous cutting test were as follows: 
Workpiece: a bar of steel (JIS.multidot.SNCM-8; Hardness: HB260) 
Cutting speed: 150 m/minute 
Feed rate: 0.44 mm/revolution 
Depth of cut: 1.5 mm 
Time: 15 minutes 
An intermittent cutting test was also carried out under the following 
cutting conditions: 
Workpiece: a block of steel (JIS.multidot.SNCM-8; Hardness: HB280) 
Cutting speed: 100 m/minute 
Feed rate: 0.335 mm/revolution 
Depth of cut: 2 mm 
Time: 5 minutes 
The results of the continuous and intermittent cutting tests are shown in 
Table 7. 
TABLE 7 
__________________________________________________________________________ 
Inter- 
mittent 
cutting 
test 
Number 
of 
chipped 
Heat treatment Continuous 
bladeng 
Pres- Pres- 
Heat Reaction layer test mem- 
Kind of 
sure 
sure 
tempera- 
Composition of oxy-carbo-nitride of 
Average 
Flank 
Crater 
bers/ 
blade of CO.sub.2 
of N.sub.2 
ture Time 
metals (Ti, M) (CxNyOz) 
thickness 
wear wear tested 
member 
(torr) 
(torr) 
(.degree.C.) 
(h) 
(molar ratio) (.mu.m) 
(mm) (.mu.m) 
members 
__________________________________________________________________________ 
Blade 
members of 
this 
invention 
34 100 -- 1100 Not measurable 0.5 0.25 40 1/10 
35 1150 20 Not measurable 0.8 0.18 30 1/10 
36 200 1200 (Ti.sub.0.69 Ta.sub.0.13 W.sub.0.08 Mo.sub.0.10)--(C 
.sub.0.50 N.sub.0.45 O.sub.0.05) 
2.0 0.16 15 1/10 
37 200 -- 1280 6 (Ti.sub.0.72 Ta.sub.0.12 W.sub.0.07 Mo.sub.0.09)--(C 
.sub.0.65 N.sub.0.25 O.sub.0.10 ) 
1.5 0.13 10 1/10 
38 100 200 (Ti.sub.0.73 Ta.sub.0.12 W.sub.0.06 Mo.sub.0.09)--(C 
.sub.0.25 N.sub.0.60 O.sub.0.15) 
3.5 0.13 10 1/10 
Compari- 
son blade 
members 
21 -- 1050* 
20 Not measurable 0.3* 0.34 50 1/10 
22 -- -- 0.46 80 2/10 
23 -- 0.52 150 5/10 
24 -- 0.33 40 3/10 
__________________________________________________________________________ 
*not falling within the range of this invention 
As can be seen from Table 7, the blade members 34 to 38 of this invention 
exhibited excellent wear resistance and excellent toughness in comparison 
with the comparison blade members 23 and 24. The reaction layer of the 
comparison blade member 21 had an average thickness of 0.3 .mu.m which is 
below the lower limit of the thickness range of this invention. The 
comparison blade member 22 had no reaction layer. Therefore, the two 
comparison blade members 21 and 22 were substantially equal in toughness 
to the blade members of this invention but were inferior in wear 
resistance. 
The following Examples 7 to 9 illustrate blade members having on a surface 
a reaction layer composed of an inner layer of carbo-nitride of metals and 
an outer layer of oxy-carbo-nitride of metals. 
EXAMPLE 7 
Cermet substrates were prepared according to the procedure of Example 1 
using the same powder materials, the cermet substrates having the same 
composition as the cermet substrates of Example 1. The cermet substrates 
were then ground into a shape conforming to JIS.multidot.SNP432. The 
cermet substrates were then subjected to heat treatment in an atmosphere 
of N.sub.2 under conditions shown in Table 8 to form a first reaction 
layer of carbo-nitride of metals on a surface thereof. Subsequently, the 
cermet substrates were subjected to heat treatment in an atmosphere of 
CO.sub.2 under conditions shown in Table 8 to form an outer reaction layer 
of oxy-carbo-nitride of metals in the first reaction layer, thereby 
producing blade members 39 to 45 of this invention and comparison blade 
members 25 and 26. The comparison blade members 25 and 26 were produced 
under the conditions not falling within the range of this invention, as 
shown in Table 8. Also, there were provided comparison blade member 27 of 
cermet containing TiC, Ni and Mo and WC-based comparison blade member 28 
having on a surface 6 .mu.m thick coating composed of a layer of TiC and a 
layer of Al.sub.2 O.sub.3. 
The blade members 39 to 45 of this invention and the comparison blade 
members 25 to 28 were subjected to a continuous cutting test and an 
intermittent cutting test for the same purposes in the above Examples. 
The conditions for the continuous cutting test were as follows: 
Workpiece: a bar of steel (JIS.multidot.SNCM-8; Hardness: HB240) 
Cutting speed: 260 m/minute 
Feed rate: 0.375 mm/revolution 
Depth of cut: 2.0 mm 
Time: 10 minutes 
The conditions for the intermittent cutting test were as follows: 
Workpiece: a block of steel (JIS.multidot.SNCM-8; Hardness: HB280) 
Cutting speed: 150 m/minute 
Feed rate: 0.33 mm/revolution 
Depth of cut: 2.0 mm 
Time: 3 minutes 
The results obtained are shown in Table 8. 
TABLE 8 
__________________________________________________________________________ 
Heat treatment Reaction layer 
Outer layer Inner layer 
Kind of Inner layer Heat tem- Composition of 
Averageitride 
blade Pressure of 
Heat temp- Pressure of 
perature of metals: (Ti, M) 
thickness 
member N.sub.2 (torr) 
erature (.degree.C.) 
Time (h) 
CO.sub.2 (torr) 
(.degree.C.) 
Time (h) 
(molar ratio) (.mu.m) 
__________________________________________________________________________ 
Blade member of 
this invention 
39 600 1240 8 300 1250 6 (Ti.sub.0.85 Ta.sub.0.05 
W.sub.0.03 Mo.sub.0.07)-- 
3.0 
(C.sub.0.18 N.sub.0.82) 
40 550 1250 7 250 1260 5 (Ti.sub.0.85 Ta.sub.0.05 
W.sub.0.03 Mo.sub.0.07)-- 
3.5 
(C.sub.0.15 N.sub.0.85) 
41 500 1260 6 200 1270 4 (Ti.sub.0.87 Ta.sub.0.05 
W.sub.0.03 Mo.sub.0.05)-- 
3.5 
(C.sub.0.15 N.sub.0.85) 
42 450 1270 5 200 1280 3 (Ti.sub.0.87 Ta.sub.0.05 
W.sub.0.03 Mo.sub.0.05)-- 
3.5 
(C.sub.0.17 N.sub.0.83) 
43 400 1280 7 250 1280 6 (Ti.sub.0.88 Ta.sub.0.04 
W.sub.0.03 Mo.sub.0.05)-- 
5.5 
(C.sub.0.20 N.sub.0.80) 
44 450 1290 11 300 1290 7 (Ti.sub.0.90 Ta.sub.0.04 
W.sub.0.03 Mo.sub.0.03)-- 
8.0 
(C.sub.0.25 N.sub.0.75) 
45 550 1300 12 300 1300 9 (Ti.sub.0.92 Ta.sub.0.03 
W.sub.0.02 Mo.sub.0.03)-- 
10.0 
(C.sub.0.30 N.sub.0.70) 
Comparison blade 
members 
25 550 1320* 15 300 1300 6 (Ti.sub.0.94 Ta.sub.0.02 
W.sub.0.02 Mo.sub.0.02)-- 
16.0 
(C.sub.0.41 N.sub.0.59) 
26 550 1300 6 400 1330* 
18 (Ti.sub.0.92 Ta.sub.0.03 
W.sub.0.02 Mo.sub.0.03)-- 
5.0 
(C.sub.0.35 N.sub.0.65) 
27 -- 
28 -- 
__________________________________________________________________________ 
Reaction layer 
Outer layer 
Composition of oxy-carbo- 
Continuous cutting 
Intermittent 
cutting test 
Kind of nitride of metals: (Ti, M) 
Average 
test Number of 
blade (CxNyOz) thickness 
Flank wear 
Crater 
chipped blade 
members/ 
member (molar ratio) (.mu.m) 
(mm) (.mu.m) 
number of tested 
members 
__________________________________________________________________________ 
Blade member of 
this invention 
39 (Ti.sub.0.90 Ta.sub.0.04 W.sub.0.02 Mo.sub.0.04)-- 
0.7 0.13 20 0/10 
(C.sub.0.35 N.sub.0.53 O.sub.0.12) 
40 (Ti.sub.0.90 Ta.sub.0.04 W.sub.0.02 Mo.sub.0.04)-- 
1.0 0.11 15 1/10 
(C.sub.0.35 N.sub.0.50 O.sub.0.15) 
41 (Ti.sub.0.92 Ta.sub.0.03 W.sub.0.02 Mo.sub.0.03)-- 
1.0 0.10 15 1/10 
(C.sub.0.35 N.sub.0.50 O.sub.0.15) 
42 (Ti.sub.0.92 Ta.sub.0.03 W.sub.0.02 Mo.sub.0.03)-- 
1.0 0.09 15 1/10 
(C.sub.0.40 N.sub.0.43 O.sub.0.17) 
43 (Ti.sub.0.92 Ta.sub.0.03 W.sub.0.02 Mo.sub.0.03)-- 
2.0 0.09 10 2/10 
(C.sub.0.43 N.sub.0.40 O.sub.0.17) 
44 (Ti.sub.0.95 Ta.sub.0.02 W.sub.0.01 Mo.sub.0.02)-- 
3.5 0.13 5 3/10 
(C.sub.0.45 N.sub.0.35 O.sub.0.20) 
45 (Ti.sub.0.95 Ta.sub.0.02 W.sub.0.01 Mo.sub.0.02)-- 
4.5 0.15 5 5/10 
(C.sub.0.48 N.sub.0.30 O.sub.0.22) 
Comparison blade 
members 
25 (Ti.sub.0.97 Ta.sub.0.01 Mo.sub.0.02)-- 
3.0 0.26 5 10/10 
(C.sub.0.55 N.sub.0.23 O.sub.0.22) 
26 (Ti.sub.0.95 Ta.sub.0.02 W.sub.0.01 Mo.sub.0.02)-- 
11.0* 
0.22 5 10/10 
(C.sub.0.50 N.sub.0.25 O.sub.0.25) 
27 -- 0.42 70 10/10 
Plastic 
deformation 
28 -- 0.39 120 5/10 
Plastic 
deformation 
__________________________________________________________________________ 
*not falling within this invention 
As can be seen from Table 8, the blade members 39 to 45 of this invention 
were much superior to the comparison blade members 27 and 28 in wear 
resistance, thermoplastic deformation resistance and toughness. The 
comparison blade member 25 had 16.0 .mu.m thick inner layer which exceeded 
the upper limit of the thickness range of this invention. The comparison 
blade member 26 had 11.0 .mu.m thick outer layer which exceeded the upper 
limit of the thickness range of this invention. These comparison blade 
members 25 and 26 were much inferior in toughness. 
EXAMPLE 8 
The same powder materials described in Example 2 were mixed together in 
ratios shown in Table 6 to provide various mixtures. Cermet substrates 8a 
to 14a and comparison substrates 5a to 8a were produced from these 
mixtures according to the same procedure of Example 2. Then, the cermet 
substrates 8a to 14a of this invention were subjected to heat treatment 
under conditions shown in Table 9 to produce blade members 46 to 52 of 
this invention, respectively. Also, the comparison substrates 5a to 8a 
were subjected to heat treatment under conditions shown in Table 9 to 
produce comparison blade members 29 to 32, respectively. The comparison 
blade members 29 and 30 had free carbon in their reaction layers and at 
portions immediately adjacent thereto. The comparison blade member 31 had 
an extremely roughened surface. 
The blade members 46 to 52 of this invention and the comparison blade 
members 29 to 32 were subjected to a continuous cutting test. The 
conditions for this continuous cutting test were as follows: 
Workpiece: a bar of steel (JIS.multidot.SNCM-8; Hardness: HB240) 
Cutting speed: 210 m/minute 
Feed rate: 0.36 mm/revolution 
Depth of cut: 2.0 mm 
Time: 10 minutes 
An intermittent cutting test was also carried out under the following 
conditions: 
Workpiece: a block of steel (JIS.multidot.SNCM-8; Hardness: HB280) 
Cutting speed: 130 m/minute 
Feed rate: 0.3 mm/revolution 
Depth of cut: 2.0 mm 
Time: 3 minutes 
The results of these two tests are shown in Table 9. 
TABLE 9 
__________________________________________________________________________ 
Heat treatment Reaction layer 
Outer layer Inner layer 
Kind of 
Inner layer Heat tem- 
Composition of 
Averageitride 
blade Pressure of 
Heat temp- 
Time 
Pressure of 
Pressure of 
perature 
Time 
of metals: (Ti, M) 
thickness 
member 
N.sub.2 (torr) 
erature (.degree.C.) 
(h) 
CO.sub.2 (torr) 
CO (torr) 
(.degree.C.) 
(h) 
(molar ratio) (.mu.m) 
__________________________________________________________________________ 
Blade 
members of 
this 
invention 
46 500 1280 5 200 1280 3 (Ti.sub.0.82 W.sub.0.04 
Mo.sub.0.14)-- 3.5 
(C.sub.0.20 N.sub.0.80) 
47 (Ti.sub.0.89 W.sub.0.03 
Mo.sub.0.08)-- 4.0 
(C.sub.0.18 N.sub.0.82) 
48 -- (Ti.sub.0.91 W.sub.0.03 
Mo.sub.0.06)-- 4.0 
(C.sub.0.15 N.sub.0.85) 
49 300 100 (Ti.sub.0.92 W.sub.0.03 
Mo.sub.0.05 )-- 4.0 
(C.sub.0.12 N.sub.0.88) 
50 (Ti.sub.0.94 W.sub.0.02 
Mo.sub.0.04)-- 4.0 
(C.sub.0.08 N.sub.0.92) 
51 500 100 (Ti.sub.0.81 Ta.sub.0.07 
Nb.sub.0.02 W.sub.0.05 Mo.sub.0. 
05)-- 3.5 
(C.sub.0.16 N.sub.0.84) 
52 (Ti.sub.0.90 Ta.sub.0.02 
W.sub.0.03 Mo.sub.0.05)-- 
4.0 
(C.sub.0.16 N.sub.0.84) 
Compari- 
son blade 
members 
29 200 (Ti.sub.0.87 W.sub.0.03 
Mo.sub.0.10)-- 3.0 
(C.sub.0.56 N.sub.0.44) 
30 -- (Ti.sub.0.89 W.sub.0.03 
Mo.sub.0.08)-- 3.5 
(C.sub.0.30 N.sub.0.70) 
31 300 100 (Ti.sub.0.95 W.sub.0.02 
Mo.sub.0.30)-- 4.0 
(C.sub.0.05 N.sub.0.95) 
32 500 200 Ti--(C.sub.0.20 N.sub.0.80) 
4.0 
__________________________________________________________________________ 
Intermittent 
Cutting test 
Reaction layer Number of 
Outer layer Continuous Chipped blade 
Composition of oxy-carbo- 
cutting members/ 
Kind of 
nitride of metals: (Ti, M) 
Average 
test number of 
blade (CxNyOz) thickness 
Flank wear 
Craft wear 
tested 
member 
(molar ratio) 
(.mu.m) 
(mm) (.mu.m) 
members 
__________________________________________________________________________ 
Blade 
members of 
this 
invention 
46 (Ti.sub.0.93 W.sub.0.02 Mo.sub.0.05)-- 
1.0 0.11 15 3/10 
(C.sub.0.40 N.sub.0.45 O.sub.0.15) 
47 (Ti.sub.0.94 W.sub.0.02 Mo.sub.0.04)-- 
1.0 0.10 10 2/10 
(C.sub.0.40 N.sub.0.45 O.sub.0.15) 
48 (Ti.sub.0.94 W.sub.0.02 Mo.sub.0.04)-- 
1.0 0.09 10 1/10 
(C.sub.0.38 N.sub.0.45 O.sub.0.17) 
49 (Ti.sub.0.95 W.sub.0.02 Mo.sub.0.03)-- 
1.0 0.10 10 2/10 
(C.sub.0.33 N.sub.0.50 O.sub.0.17) 
50 (Ti.sub.0.97 W.sub.0.01 Mo.sub.0.02)-- 
1.0 0.15 10 3/10 
(C.sub.0.25 N.sub.0.55 O.sub.0.20) 
51 (Ti.sub.0.92 Ta.sub.0.03 Nb.sub.0.01 W.sub.0.02 
1.0 0.13 15 1/10 
Mo.sub.0.02) (C.sub.0.38 N.sub.0.45 O.sub.0.17) 
52 (Ti.sub.0.96 Ta.sub.0.01 W.sub.0.01 Mo.sub.0.02) 
1.0 0.11 15 1/10 
(C.sub.0.38 N.sub.0.45 O.sub.0.17) 
Compari- 
son blade 
members 
29 (Ti.sub.0.94 W.sub.0.01 Mo.sub.0.05)-- 
1.0 0.30 40 10/10 
(C.sub.0.60 N.sub.0.33 O.sub.0.07) 
30 (Ti.sub.0.95 W.sub.0.01 Mo.sub.0.04)-- 
1.0 0.28 30 7/10 
(C.sub.0.45 N.sub.0.45 O.sub.0.10) 
31 (Ti.sub.0.98 W.sub.0.01 Mo.sub.0.01)-- 
1.0 0.35 15 9/10 
(C.sub.0.25 N.sub.0.50 O.sub.0.25) 
32 Ti--(C.sub.0.40 N.sub.0.45 O.sub.0.15) 
1.0 0.25 30 10/10 
__________________________________________________________________________ 
As can be seen from Table 9, the blade members 46 to 52 exhibited excellent 
wear resistance and excellent toughness and achieved a good cutting 
performance. On the other hand, the comparison blade members 29 to 32 
whose substrates had the compositions not falling within the range of this 
invention, were very inferior in wear resistance toughness and exhibited a 
poor cutting performance. 
EXAMPLE 9 
Cermet substrates, composed of 26.5% by volume TiC, 20% TiN, 10% TaC, 15% 
WC, 10% Mo, 5.5% Ni, 11% Co and 2% Al (the volume ratio of TiN to TiC plus 
TiN: 0.43), were prepared according to the procedure of Example 1. The 
cermet substrates were subjected to heat treatment under conditions shown 
in Table 10 to produce blade members 53 to 57 of this invention and 
comparison blade members 33 to 36. The cermet substrate not subjected to 
the heat treatment was used as comparison blade member 36. Also, there 
were provided WC-based comparison blade member 37 (JIS.multidot.P10) and 
comparison WC-based blade member 38 having on a surface 7 .mu.m thick 
coating composed of TiC layer and TiN layer. 
The blade members 53 to 57 of this invention and the comparison blade 
members 33 to 38 were subjected to a continuous cutting test. The 
conditions for this continuous cutting test were as follows: 
Workpiece: a bar of steel (JIS.multidot.SNCM-8; Hardness: HB240) 
Cutting speed: 150 m/minute 
Feed rate: 0.475 mm/revolution 
Depth of cut: 2.0 mm 
Time: 15 minutes 
An intermittent cutting test was also carried out under the following 
cutting conditions: 
Workpiece: a block of steel (JIS.multidot.SNCM-8; Hardness: HB280) 
Cutting speed: 110 m/minute 
Feed rate: 0.375 mm/revolution 
Depth of cut: 2.0 mm 
Time: 3 minutes 
The results of the continuous and intermittent cutting tests are shown in 
Table 10. 
TABLE 10 
__________________________________________________________________________ 
Heat treatment Reaction layer 
Outer layer Inner layer 
Kind of 
Inner layer Heat tem- 
Composition of carbo-nitride 
of Average 
blade Pressure of 
Heat temp- 
Time 
Pressure of 
Pressure of 
perature 
Time 
metals: (Ti, M) 
thickness 
member N.sub.2 (torr) 
erature (.degree.C.) 
(h) 
CO.sub.2 (torr) 
CO (torr) 
(.degree.C.) 
(h) 
(molar ratio) (.mu.m) 
__________________________________________________________________________ 
Blade 
members of 
this invention 
53 200 1100 10 -- 100 1100 10 Not measurable 0.3 
54 1150 1150 Not measurable 0.6 
55 300 1200 10 1200 10 (Ti.sub.0.82 Ta.sub.0.08 
W.sub.0.05 Mo.sub.0.05)-- 
2.0 
(C.sub.0.30 N.sub.0.70) 
56 400 1260 5 100 1260 6 (Ti.sub.0.87 Ta.sub.0.06 
W.sub.0.04 Mo.sub.0.03)-- 
2.5 
(C.sub.0.16 N.sub.0.84) 
57 500 1280 5 1280 4 (Ti.sub.0.88 Ta.sub.0.06 
W.sub.0.03 Mo.sub.0.03) 
3.0 
(C.sub.0.15 N.sub.0.85) 
Comparison 
blade 
members 
33 200 1050* 
12 -- Not measurable 0.2 
34 -- -- 100 1050 10 -- -- 
35 200 1050 10 Not measurable 0.1* 
36 -- 
37 -- 
38 -- 
__________________________________________________________________________ 
Intermittent 
cutting test 
Reaction layer Number of 
Outer layer Continuous chipped blade 
Composition of oxy-carbo- 
cutting members/ 
Kind of 
nitride of metals: (Ti, M) 
Average 
test number of 
blade (CxNyOz) thickness 
Flank wear 
Crater 
tested 
member (molar ratio) 
(.mu.m) 
(mm) (.mu.m) 
members 
__________________________________________________________________________ 
Blade 
members of 
this invention 
53 Not measurable 
0.2 0.19 30 0/10 
54 Not measurable 
0.4 0.14 20 0/10 
55 (Ti.sub.0.90 Ta.sub.0.04 W.sub.0.03 Mo.sub.0.03)- 
- 1.0 0.11 10 1/10 
(C.sub.0.35 N.sub.0.55 O.sub.0.10) 
56 (Ti.sub.0.92 Ta.sub.0.04 W.sub.0.02 Mo.sub. 
0.02)-- 1.0 0.10 10 1/10 
(C.sub.0.35 N.sub.0.50 O.sub.0.15) 
57 (Ti.sub.0.92 Ta.sub.0.04 W.sub.0.02 Mo.sub.0.02)- 
- 1.5 0.09 5 1/10 
(C.sub.0.40 N.sub.0.43 O.sub.0.17) 
Comparison 
blade 
members 
33 -- -- 0.40 70 0/10 
34 Not measurable 
0.1* 
0.36 50 0/10 
35 Not measurable 
0.1* 
0.29 45 0/10 
36 -- 0.48 80 1/10 
37 -- 0.57 170 5/10 
38 -- 0.40 80 3/10 
__________________________________________________________________________ 
*not falling within the range of this invention 
As can be seen from Table 10, the blade members 53 to 57 of this invention 
exhibited excellent wear resistance and excellent toughness in comparison 
with the comparison blade members 37 and 38. The reaction layer of each of 
the comparison blade members 33 to 35 were below the lower limit of the 
thickness range of this invention. Further, the reaction layer of each of 
the comparison blade members 33 and 34 was a single layer. The comparison 
blade member 36 had no reaction layer. Although these comparison blade 
members 33 to 36 were substantially equal in toughness to the blade 
members of this invention, they were quite inferior in wear resistance.