JP3374653B2 - Carbonitride cermet cutting tool with excellent wear resistance - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carbonitriding material having excellent wear resistance and exhibiting excellent cutting performance in high-speed cutting of, for example, steel for a long time. The present invention relates to a material-based cermet cutting tool (hereinafter, referred to as a cermet tool). 2. Description of the Related Art Conventionally, for example, Japanese Patent Laid-Open No. 2-190438
As described in Japanese Unexamined Patent Publication, as a cermet tool used for cutting steel or the like, the volume% (hereinafter,% is the volume%
), The titanium carbonitride having a single phase structure (hereinafter, referred to as
Phase: 2 to 20%; Co—Ni-based alloy bonded phase: 5 to 30%; Ti, W and N having a single phase structure
b and / or Ta complex carbonitride solid solution (hereinafter, referred to as
Phase (indicated by Ti, W, Nb / Ta) CN) and inevitable impurities: the composition consisting of the remainder, and the binder phase forms a continuous phase, as illustrated in the schematic structure diagram in FIG. , W, Nb / Ta) A cermet tool composed of a carbonitride-based cermet (hereinafter referred to as a cermet) having a structure in which a CN phase and a TiCN phase form a dispersed phase is known. On the other hand, the performance of cutting devices has been remarkably improved in recent years, and there has been a strong demand for energy saving and labor saving. In the case where the above-mentioned conventional cermet is used, for example, for high-speed cutting of steel, at present, wear is remarkable, and the service life is relatively short. [0004] Therefore, the present inventors have proposed:
From the above point of view, focusing on the conventional cermet tool described above, as a result of researching to improve the wear resistance, when producing the conventional cermet tool, the sintering of the green compact, the usual Conditions, that is, (a) from room temperature to the temperature of (liquid phase appearance temperature −20 ° C.)
(B) After raising the temperature in a vacuum atmosphere of 0.5 Torr, and then changing to a nitrogen atmosphere of 5 to 15 Torr, 1400
(C) heating to a predetermined sintering temperature within a range of 1520 ° C.
Subsequently, the sintering is performed in the same nitrogen atmosphere under the conditions of maintaining the sintering temperature at the sintering temperature for a predetermined time and then cooling the furnace.
Raising the temperature from room temperature to a predetermined temperature in the range of 1200 to 1270 ° C. in a nitrogen atmosphere of 0.5 to 1.5 Torr,
(B) After the temperature was raised, the atmosphere was changed to a mixed gas of hydrogen and methane at 5 to 10 Torr (methane content: 1 to 15%), and the temperature was raised to the temperature of (liquid phase appearance temperature -50 ° C). (C) Subsequently, the atmosphere is changed to 5
1400-152 instead of nitrogen atmosphere of ~ 15 Torr
If the temperature is raised to a sintering temperature in the range of 0 ° C. and (d) the temperature is kept at the sintering temperature for a predetermined time in the same nitrogen atmosphere and then the furnace is cooled, the temperature rising process to the sintering temperature is particularly performed. That is,
The temperature rise in the nitrogen atmosphere, the subsequent temperature rise in the mixed gas atmosphere, and the holding for a predetermined time in the mixed gas atmosphere cause worm-like growth of (Ti, W, Nb / Ta) CN. , Thereby obtaining (Ti, W, Nb / T
a) CN is locally fused to each other to form a continuous phase, and as a result, the cermet after sintering has a worm during sintering as illustrated in the structural schematic diagrams in FIGS. (Ti, W, Nb / Ta) CN phase 1 which grows in a local state is locally fused to each other to form a continuous phase, and a bonding phase 3 of a Co—Ni-based alloy is formed.
Is present as a dispersed phase between the (Ti, W, Nb / Ta) CN phase and the TiCN phase 2 is present in the binder phase or in the binder phase and the (Ti, W, Nb / Ta) CN phase. Since it has a structure distributed as a dispersed phase in the cermet, the cermet tool composed of this cermet grows into a worm-like shape before forming a continuous phase, for example, by high-speed cutting of steel, and is fused together. (Ti, W, Ni / T
a) A study result was obtained that exerts excellent wear resistance over a long period of time by the action of the CN phase. [0005] The present invention has been made based on the above-mentioned research results, and has a TiCN having a single-phase structure.
Phase: 2 to 20%, Co-Ni alloy bonded phase: 5 to 20
%, Also having a single phase structure (Ti, W, Nb / T
a) CN phase and unavoidable impurities: composition consisting of the remainder,
(Ti, W, N)
b / Ta) CN phase is locally fused to each other to form a continuous phase, the binder phase exists as a dispersed phase between the (Ti, W, Nb / Ta) CN phase, and the TiCN phase is In the binder phase, or the binder phase and the (Ti, W,
(NbTa) A cermet tool comprising a cermet having a structure distributed as a dispersed phase in a CN phase. The cermet constituting the cermet tool of the present invention is a constituent component (Ti, W, Nb / T).
a) The CN phase is composed of Ti, W and Nb /
When the content ratio of Ta satisfies the ratio (atomic%) of these metal components, W: 5 to 25%, Nb / Ta: 6 to 30%, Ti: remaining Growth occurs, mutual fusion is likely to occur, and the formation of a continuous phase is promoted. Further, in the cermet constituting the cermet tool of the present invention, the TiCN phase has an effect of improving the plastic deformation resistance of the tool. If the ratio is less than 2%, the desired effect of improving the plastic deformation resistance is obtained. On the other hand, if the proportion exceeds 20%, the toughness decreases, and chipping and chipping easily occur on the cutting edge.
20%, desirably 2 to 12%. Further, the binder phase has an effect of improving sinterability and thereby increasing the strength and toughness of the tool. The desired effect was not obtained, while the ratio was 2
If it exceeds 0%, the growth of the (Ti, W, Nb / Ta) CN phase is suppressed, and the formation of a continuous phase becomes difficult, and the desired effect of improving wear resistance cannot be obtained. It is 5 to 20%, preferably 7 to 12%. Next, a cermet tool according to the present invention will be described in detail with reference to embodiments. As raw material powders, all have a predetermined average particle size in the range of 0.5 to 2 μm, and in terms of weight ratio (hereinafter the same), TiC / TiN / W
(Ti, W, Nb) CN powder having a composition of C / NbC = 30/30/30/10 (hereinafter referred to as solid solution A powder), TiC / TiN / WC / TaC = 30/30/3
(Ti, W, Ta) CN powder having a composition of 0/10 / (hereinafter referred to as solid solution B powder), TiC / TiN / WC
/ NbC / TaC = 30/30/20/10/10 (Ti, W, Nb, Ta) CN powder
Solid solution C powder), TiC / TiN / WC = 30 /
(Ti, W, Ta) CN powder having a composition of 30/40 (hereinafter referred to as solid solution D powder), further TiCN powder,
TiN powder, NbC powder, TaC powder, WC powder, Co
Powder and Ni powder were prepared, and these raw material powders were listed in Table 1.
, And wet-mixed in a ball mill for 72 hours, dried, and then press-molded into green compacts A to T at a pressure of 1.5 ton / cm ² . Next, the green compacts A to T were subjected to the following conditions: (a) from room temperature to 1250 ° C. for 0.5 To
(b) After the temperature was raised to 1250 ° C., a mixed gas of hydrogen and methane at 8 Torr (methane:
1% / m up to 1320 ° C instead of atmosphere
in. (C) Subsequently, the atmosphere is maintained at the above-mentioned atmosphere and temperature for 1 hour. (C) Subsequently, the atmosphere is changed to a nitrogen atmosphere of 10 Torr and a predetermined sintering temperature in the range of 1400 to 1520 ° C. is raised to 2 ° C. / Min. The cermet tools 1 to 20 of the present invention each having a throw-away tip shape in accordance with the standard of SNMG432 by sintering under the following conditions: Manufactured. Further, the green compacts A to T are formed under the following conditions:
That is, (a) 0.2T from room temperature to 1350 ° C.
(b) After the temperature was raised to 1350 ° C., the temperature was increased to 1400 ° C. after changing to a nitrogen atmosphere of 10 Torr.
The temperature is raised to a predetermined sintering temperature in the range of 1520 ° C., and the sintering is carried out under the conditions of holding at this sintering temperature for 1 hour and then cooling in a furnace. Manufactured. With respect to the various cermet tools obtained as a result, the structure of the cermets constituting the tools was observed using an Auger electron spectroscopic analyzer and an image processing analyzer, and the content ratio of the constituent phases was measured. In addition, FIGS. 1 to 3 schematically show the results of microscopic observation (× 4000) using a scanning electron microscope. FIG. 1 is a schematic diagram of the cermet tool 2 of the present invention, FIG. 2 is a schematic diagram of the cermet tool 3 of the present invention, and FIG. Further, regarding the above various cermet tools, work material: JIS-SNCM439 (hardness: HB270)
Round bar, Cutting speed: 350 m / min. Infeed: 2.0 mm Feed: 0.35 mm / rev. A dry continuous high-speed cutting test was performed on the steel under the following conditions, and the cutting time until the flank wear width of the cutting edge reached 0.2 mm was measured. The results are shown in Tables 2 and 3. [Table 1] [Table 2] [Table 3] The cermet tools 1 to 20 according to the present invention all have any of the tissues exemplified in FIGS. ,
W, Nb / Ta) CN phase forms a continuous phase, C
The binder phase of the o-Ni alloy is (Ti, W, Nb / T
a) exists as a dispersed phase between the CN phases, and further, a TiCN phase is contained in the binder phase or the binder phase and the (Ti, W, Nb /
Ta) showing a structure distributed as a dispersed phase in the CN phase,
On the other hand, the conventional cermet tools 1 to 20 each have a structure illustrated in FIG. 3, that is, a bonding phase forming a continuous phase,
All form a dispersed phase (Ti, W, Nb / Ta) C
It shows a structure composed of an N phase and a TiCN phase, and as shown in Tables 2 and 3 due to the difference in the structure, the cermet tools 1 to 20 of the present invention are higher in cutting speed of steel than the conventional cermet tools 1 to 20. It is evident that it will exhibit even better wear resistance. As described above, the cermet tool of the present invention exhibits excellent wear resistance over a long period of time, not only in normal cutting but also in high-speed cutting. Can be fully satisfied.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic structural view of a cermet constituting a cermet tool 2 of the present invention. FIG. 2 is a schematic structural view of a cermet constituting the cermet tool 3 of the present invention. FIG. 3 is a schematic structural view of a cermet constituting a conventional cermet tool 20. [Description of Signs] 1 (Ti, W, Nb / Ta) CN phase 2 TiCN phase 3 Bound phase

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B23B 27/14 C22C 29/04

Claims (1)

(57) [Claims 1] Titanium carbonitride phase having a single phase structure: 2
２０20%, Co—Ni alloy binder phase: 5-20%, Ti, W, Nb and / or Ta having a single phase structure
Composite carbonitride solid solution phase and unavoidable impurities of the following: composition consisting of the remainder (above, volume%), and the above composite carbonitride solid solution phase which grew like worms at the time of sintering were locally fused and continuous. Forming a phase, wherein the binder phase is present as a dispersed phase between the composite carbonitride solid solution phase, and the titanium carbonitride phase is in the binder phase, or in the binder phase and the composite carbonitride solid solution phase. A cutting tool made of carbonitride-based cermet having excellent wear resistance, characterized by having a structure distributed as a dispersed phase.