JP3397058B2 - Surface-coated cemented carbide cutting tool with excellent wear resistance - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has excellent wear resistance and therefore exhibits excellent cutting performance over a long period of time, for example, in continuous cutting and interrupted cutting of steel. The present invention relates to a surface-coated cemented carbide cutting tool (hereinafter referred to as a coated cemented carbide tool). 2. Description of the Related Art Conventionally, generally, for example, an arc ion plating apparatus which is a kind of physical vapor deposition apparatus schematically shown in FIG. 1 is used.
At a temperature of 0 ° C., an arc discharge is generated between the anode electrode and a cathode electrode (evaporation source) on which a Cr—Ti alloy having a predetermined composition is set, and at the same time, nitrogen gas is used as a reaction gas in the apparatus. Or a nitrogen gas and a methane gas are introduced, while a tungsten carbide (hereinafter abbreviated as WC) -based cemented carbide or a titanium carbonitride (hereinafter abbreviated as TiCN) -based cermet (hereinafter collectively referred to as a For example, as described in JP-A-7-243047, a Cr-Ti composite nitride is formed on the surface of the cemented carbide substrate under the condition that a bias voltage of -120 V is applied. [Hereinafter, (Cr, Ti)
N] and a Cr-Ti composite carbonitride [hereinafter referred to as (C
r, Ti) CN] or a single or multiple hard coating layer composed of
It is known to produce coated cemented carbide tools by vapor deposition with an average layer thickness of 20 μm. [0003] On the other hand, in recent years, FA and speeding of cutting work are remarkable, and there is a strong demand for labor saving and energy saving of cutting work.
It is strongly desired to extend the service life of cutting tools.
In the case of the above-mentioned conventional coated cemented carbide tools, the hard coating layer that constitutes it has excellent chipping resistance (the property that the cutting edge is not easily chipped), but the wear resistance is not enough. At present, the service life is reached in a very short time. [0004] Therefore, the present inventors have proposed:
From the above viewpoints, (Cr, Ti) N and (Cr, Ti) constituting the hard coating layer of the conventional coated cemented carbide tool described above.
Ti) focused on CN, result of research to achieve this improve wear resistance, in which the by-containing Mg, Ca, and any of Sr, the composition _{formula: (Cr a Ti b M c} ) N, and the composition _{formula: (Cr a Ti b M c} ) C d N 1 _over d, (provided that an atomic ratio, a: 0.5~0.7, b: 0.1
~ 0.49, c: 0.01 ~ 0.2, a + b + c = 1,
d: 0.01 to 0.5, and M represents any of Mg, Ca, and Sr).
-Based composite nitride [hereinafter, referred to as (Cr, Ti, M) N] and Cr-Ti-based composite carbonitride [hereinafter, referred to as (Cr, Ti, M)
M) CN], or both of them constitute a hard coating layer, the resulting coated cemented carbide tool has the (Cr, Ti, M) N and (Cr, Ti,
M) With CN maintaining excellent chipping resistance,
Research results have shown that, since it has excellent wear resistance, for example, continuous cutting and intermittent cutting of steel exhibit excellent cutting performance over a long period of time. The present invention has been made on the basis of the above research results, and has a surface of a cemented carbide substrate having a thickness of 0.5 to 0.5 mm.
The hard coating layer of a single layer or multiple layers to be deposited with an average layer thickness of 20 [mu] m, the composition _{formula: (Cr a Ti b M c} ) N, and the composition _{formula: (Cr a Ti b M c} ) C d N 1 _{over d} , (However, in atomic ratio, a: 0.5 to 0.7, b: 0.1
~ 0.49, c: 0.01 ~ 0.2, a + b + c = 1,
d: 0.01 to 0.5, M represents any one of Mg, Ca, and Sr) (Cr, T
The present invention is characterized by a coated hard cemented carbide tool having excellent wear resistance, comprising one or both of (i, M) N and (Cr, Ti, M) CN. In addition,
In the coated cemented carbide tool of the present invention, in order to facilitate discrimination before and after use, the hard coated titanium nitride (TiN) layer having an average thickness of 0.1 to 1 μm is used. It may be deposited on the surface of the layer. Next, (Cr, Ti, M) N and (C) constituting the hard coating layer of the coated cemented carbide tool of the present invention.
The reason why the composition ratio (atomic ratio) of (r, Ti, M) CN is limited as described above will be described. That is, the above (Cr, T
In (i, M) N and (Cr, Ti, M) CN, Cr and Ti as constituents have an effect of contributing to the improvement of chipping resistance of the cutting edge in a coexisting state.
In any of the cases, if Cr: less than 0.5 and Ti: less than 0.1, the desired excellent chipping resistance cannot be ensured. On the other hand, in the case of either Cr or Ti, the ratio is Cr: 0. When the content exceeds 0.7 and Ti: 0.49, the wear resistance rapidly decreases.
The ratio is Cr: 0.5 to 0.7, preferably 0.5 to 0.7.
0.65, Ti: 0.1 to 0.49, desirably 0.2
5 to 0.49. In addition, the same constituent component M
(Any of Mg, Ca, and Sr) has the effect of improving wear resistance and thus enabling long-term cutting, but if the ratio is less than 0.01, desired wear resistance is obtained. No improvement effect can be obtained. On the other hand, if the ratio exceeds 0.2, the hardness of the layer itself sharply increases, and Cr and Ti
Since the excellent chipping resistance brought by the above cannot be secured, the ratio is set to 0.01 to
0.2, desirably 0.01 to 0.1. Further, the C component in (Cr, Ti, M) CN has an effect of increasing the hardness and thereby improving the wear resistance.
(Cr, Ti, M) CN has relatively higher wear resistance than the above (Cr, Ti, M) N, but in this case, if the ratio of the C component is less than 0.01, the predetermined hardness is improved. When the effect is not obtained, on the other hand, when the ratio exceeds 0.5, the toughness is rapidly reduced and chipping is likely to occur on the cutting edge. Therefore, the ratio of the C component is 0.01 to 0.5, desirably. 0.1-0.
45. In addition, the average layer thickness of the hard coating layer is set to 0.
The reason why the thickness is set to 5 to 20 μm is that if the layer thickness is less than 0.5 μm, the desired wear resistance cannot be secured, while if the layer thickness exceeds 20 μm, chipping tends to occur on the cutting edge. The average layer thickness is preferably 2 to 10 μm. When a TiN layer is deposited on the surface of the hard coating layer, the average layer thickness is set to 0.1 to 1 μm. If the layer thickness is less than 0.1 μm, a clear golden color cannot be provided. The desired golden color is due to the fact that a layer thickness of up to 1 μm is sufficient. Next, a coated cemented carbide tool according to the present invention will be described in detail with reference to examples. WC powder having an average particle diameter of 1 to 3 μm,
A TiC powder, a TaC powder, a NbC powder, and a Co powder were prepared, and these raw material powders were WC: 72% by weight,
TiC: 8%, TaC: 9%, NbC: 2%, Co: 9
%, Wet-mixed in a ball mill for 72 hours, dried, and then pressed into a green compact at a pressure of 1.5 ton / cm ² , and the green compact is heated in a vacuum at a temperature of 1400.
Sintering under the condition of holding at 1 ° C. for 1 hour.
A cemented carbide substrate A made of a WC-based cemented carbide having a chip shape of NGN120408 was formed. In addition, TiC having an average particle size of 0.5 to 2 μm is used as a raw material powder.
N (TiC / TiN = 50/50 by weight) powder, Mo
₂ C powder, TaC powder, WC powder, Co powder, and N
i powder was prepared, and these raw material powders were
N: 50%, Mo ₂ C: 8%, WC: 15%, TaC:
8%, Co: 12%, Ni: 7%
After wet mixing with a ball mill for 24 hours and drying, 1 to
The green compact is press-molded at a pressure of n / cm ² , and the green compact is heated to 1540 ° C. in a nitrogen atmosphere of 10 torr.
After sintering under the condition of holding time, and after sintering, R: 0.
03 Honing process and ISO standard SEEN1
A cemented carbide substrate B made of TiCN-based cermet having a chip shape of 203AFTN1 was formed. Next, these cemented carbide substrates A and B are ultrasonically cleaned in acetone, dried, and charged into an arc ion plating apparatus shown in FIG. 1 respectively. ) as equipped with a Cr-Ti-M alloy and Cr-Ti alloy having various component compositions, evacuation to the device as a 1 × 10 ^over 5 torr of vacuum first, and 500 ° C. in the apparatus with a heater And then Ar gas was introduced into the apparatus, and 1 × 10 ^-3 torr
After applying a bias voltage of -800 V to the substrate and bombarding the surface of the substrate,
Nitrogen gas or nitrogen gas and methane gas are introduced into the apparatus as a reaction gas, the atmosphere is set to 5 × 10 ⁻³ torr, and the bias voltage applied to the cemented carbide substrate is set to −20.
0 V, an arc discharge is generated between the cathode electrode and the anode electrode.
By forming a hard coating layer having the composition and the average layer thickness shown in Tables 1 and 2 on the respective surfaces of the above, the coated cemented carbide tools 1 to 12 of the present invention and the conventionally coated cemented carbide tools 1 to 4 Each was manufactured. [0009] Of the various coated cemented carbide tools obtained as a result, the coated cemented carbide tools 1 to 6 of the present invention and the conventional coated cemented carbide tools 1 and 2 are as follows: Work material: JIS SCM440 circle Bar, cutting speed: 300 m / min, feed: 0.3 mm / rev, depth of cut: 2 mm, dry high-speed continuous cutting test of alloy steel was performed, and coated cemented carbide tools 7 to 12 according to the present invention and conventional coated super For hard alloy tools 3 and 4, a dry high-speed continuous cutting test of alloy steel was performed under the following conditions: work material: JIS SCM440, cutting speed: 300 m / min, feed: 0.25 mm / rev, cutting depth: 1.5 mm. In each cutting test, the cutting time until the flank wear width of the cutting edge reached 0.3 mm was measured. Table 3 shows the measurement results.
It was shown to. [Table 1] [Table 2] [Table 3] From the results shown in Tables 1 to 3, all of the coated cemented carbide tools 1 to 12 of the present invention can be cut under severe conditions by high-speed continuous cutting of steel. Alloy tool 1
It is evident that the abrasion resistance is much higher than that of No. 4. As described above, the coated cemented carbide tool according to the present invention has the above-mentioned (Cr, Ti,
Since M) N and (Cr, Ti, M) CN have excellent wear resistance while maintaining excellent chipping resistance, for example, continuous cutting and interrupted cutting of steel under ordinary conditions are, of course, possible. That is, even in high-speed cutting, which is a cutting process under more severe conditions, the cutting edge does not generate chipping and exhibits excellent cutting performance for a remarkably long period.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic explanatory view of an arc ion plating apparatus.

Continued on the front page (72) Inventor Keiichi Sakurai 1511 Furamagi, Ishishita-cho, Yuki-gun, Ibaraki Pref. Mitsubishi Materials Corporation Tsukuba Works (56) References JP-A-7-173608 (JP, A) JP-A-8- 199340 (JP, A) JP 5-82471 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23C 14/00-14/58 C23C 16/00-16/56 B23B 27/14 B23P 15/28

Claims (1)

(57) [Claim 1] A surface of a tungsten carbide-based cemented carbide substrate or a titanium carbonitride-based cermet substrate has a thickness of 0.5 to 20%.
The single layer or multilayer hard coating layer to be deposited with an average layer thickness of [mu] m, the composition _{formula: (Cr a Ti b M c} ) N, and the composition _{formula: (Cr a Ti b M c} ) C d N 1 _{over d} , (However, in atomic ratio, a: 0.5 to 0.7, b: 0.1
~ 0.49, c: 0.01 ~ 0.2, a + b + c = 1,
d: 0.01 to 0.5, and M represents any of Mg, Ca, and Sr).
A cutting tool made of a surface-coated cemented carbide having excellent wear resistance, characterized in that the cutting tool is made of one or both of a composite nitride and a Cr-Ti composite carbonitride.