JP3161346B2 - Titanium carbonitride-based cermet throw-away cutting inserts with excellent wear and chipping resistance - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a cutting edge ridge where a flank and a rake face of a cutting edge intersect (hereinafter simply referred to as a cutting edge ridge), and the flank and the rake face have different hardnesses. , A slow-way type cutting tip made of titanium carbonitride-based cermet which has excellent wear resistance and chipping resistance (hereinafter simply referred to as cutting tip).
It is about.

[0002]

2. Description of the Related Art Conventionally, generally, for example, JP-A-3-3250
No. 2, as described in JP-B-2, etc., containing 3 to 20% by weight of Co and / or Ni as a binder phase forming component, and having a Vickers hardness of 1400 to 1800 inside,
The maximum surface hardness is 2400 Vickers hardness on the flank of the cutting edge, the cutting edge ridge, and the surface over the rake face.
A cutting tip formed with a surface hardened layer having a uniform hardness distribution of 2800 is known, and it is also known that the cutting tip is used for continuous cutting or interrupted cutting of, for example, steel. Further, the cutting tip, the following conditions,
(A) Heating rate to sintering temperature: 1 to 3 ° C / sec; (b) Heating atmosphere from room temperature to 1200 to 1350 ° C:
A vacuum of 0.1 torr or less, (c) a sintering temperature of 1200 to 1350 ° C.
Temperature rising atmosphere to 0 to 1560 ° C: nitrogen atmosphere of 5 to 30 torr, (d) Holding time and atmosphere at the above sintering temperature: 60 to
(E) Cooling: furnace cooling in a vacuum atmosphere of 0.1 torr or less, under a condition satisfying the above conditions (a) to (e), a compact having a predetermined compounding composition It is also known to be manufactured by sintering a body.

[0003]

On the other hand, in recent years, there has been a strong demand for labor saving and energy saving for cutting work, and the cutting work has tended to be accelerated accordingly. In conventional cutting inserts that do not change, if this is used when performing continuous cutting or intermittent cutting at high speed,
Chipping is likely to occur on the flank and rake face of the cutting blade, and at present the service life is reached in a relatively short time.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the above viewpoint, we focused on the conventional cutting insert with a surface hardened layer formed on the above surface part, and conducted research to improve chipping resistance while maintaining excellent wear resistance. , Co as a binder phase forming component and / or
Or, after specifying the content of Ni as 7 to 17% by weight,
The conditions for sintering the above-mentioned conventional cutting tips are (a) to (e).
The cooling atmosphere of the condition (e) of the conditions (1) to (5)
When sintering is performed under a nitrogen atmosphere of r, the cutting edge after sintering has a Vickers cutting edge with a relatively higher hardness than the surface hardened layer of the conventional cutting tip. The flank face and the rake face exhibit a relatively low Hv: a surface hardened layer exhibiting a maximum surface hardness of 1800 to 2200, which has a maximum surface hardness of 2600 to 3000 in terms of hardness (Hv). The cutting edge with such a hardened layer ensures excellent wear resistance due to the relatively high hardness of the cutting edge ridge even when used for high-speed continuous cutting and high-speed interrupted cutting. In addition, the occurrence of chipping was suppressed by the flank and rake face having relatively low hardness, and a research result that excellent cutting performance was exhibited over a long period of time was obtained.

The present invention has been made on the basis of the above-mentioned research results, and contains 7 to 17% by weight of Co and / or Ni as a binder phase forming component and has an H inside.
v: On the surface of the cutting tip having a hardness of 1400 to 1800, the maximum surface hardness at the cutting edge ridge is Hv: 26.
It has a feature of a cutting tip having excellent wear resistance and chipping resistance, which is formed by forming a surface hardened layer having a maximum surface hardness of Hv: 1800 to 2200 on the flank and the rake face. Things.

The hardness distribution in the hardened surface layer of the cutting tip according to the present invention is determined by specifying the content of Co and / or Ni, which is a binder phase forming component, at 7 to 17% by weight, as described above. (A)
The cooling atmosphere of the condition (e) among the conditions (e)
It is adjusted by sintering under the condition of a nitrogen atmosphere of 5 torr, that is, Co and / or Ni
The lower the content of Ni in the above range and the higher the pressure of the nitrogen atmosphere in the above condition (e) in the above range, the higher the hardness of the ridge portion of the cutting edge, the flank face and the rake face, and conversely, Co And / or the higher the Ni content within the above range and the lower the pressure of the nitrogen atmosphere, the lower the hardness. Therefore, the content of the binder phase forming component exceeds 17% by weight, And the nitrogen atmosphere is 1t
If it is less than orr, the maximum surface hardness of the ridge of the cutting edge is H
v: less than 2600, the maximum surface hardness of the flank and rake face is less than Hv: 1800, and it becomes impossible to secure desired excellent wear resistance. On the other hand, the content of the binder phase forming component is reduced. When the nitrogen atmosphere exceeds 5 torr with less than 7% by weight, the maximum surface hardness of the cutting edge ridge portion exceeds Hv: 3000, and the maximum surface hardness of the flank and rake surface exceeds Hv: 2200. Thus, the hardness distribution of the hardened surface layer was determined as described above because chipping easily occurred on the cutting blade.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the cutting insert of the present invention will be described in detail with reference to examples. As a raw material powder, TiCN having a predetermined average particle diameter in the range of 0.5 to 2 μm [weight ratio (the same applies hereinafter), TiC / TiN = 5
0/50] powder, TiN powder, TaC powder, NbC powder, WC powder, Mo ₂ C powder, VC powder, ZrC powder,
Cr ₃ C ₂ powder, (Ti, W, Mo) CN [Ti / W /
Mo = 80/10/10, C / N = 70/30] powder,
(Ti, Ta, V) CN [Ti / Ta / V = 70/20
/ 10, C / N = 50/50] powder, (Ti, Ta, N
b) CN [Ti / Ta / Nb = 70/15/15, C /
N = 60/40] powder, (Ti, W, Nb) CN [Ti
/ W / Nb = 80/10/10, C / N = 70/30]
Powder, (Ti, Nb, Mo) CN [Ti / Nb / Mo =
60/30/10, C / N = 60/40] powder, (T
i, W) CN [Ti / W = 80/20, C / N = 70 /
30] A powder, a Co powder, and a Ni powder are prepared, and these raw material powders are blended in the blending composition shown in Table 1, wet-mixed in a ball mill for 24 hours, dried, and then 1 ton / c.
The green compacts A to M are press-molded at a pressure of m ² , and then these green compacts A to M are subjected to the following conditions, that is, from room temperature to 1350 ° C. in a vacuum atmosphere of 0.05 torr,
The temperature was raised at a rate of 1.5 ° C./min to 1350 ° C., the atmosphere was changed to a nitrogen atmosphere of 10 torr, the temperature was raised to 1520 ° C. at the same rate, and 152
Hold at 0 ° C. for 60 minutes, and finally 1 to 5 torr
r, sintering in a predetermined nitrogen atmosphere within a predetermined nitrogen atmosphere under furnace cooling conditions, and performing a 0.05 mm round honing on the sintered body to obtain a cutting insert of the present invention having a throw-away insert shape according to ISO standard SNMG120408. 1 to 13 were manufactured respectively. Further, for the purpose of comparison, the above-mentioned green compacts A to M
The conventional cutting tips 1 to 13 were manufactured under the same conditions except that the sintering was performed in a nitrogen atmosphere of 0.05 torr, which was the final step of the above sintering conditions. .

[0008] With respect to the various cutting chips obtained as a result, the Vickers hardness (load: 300 g) of the flank and the rake face (load: 300 g) was determined for each one of the polished surfaces while the surface was polished.
Since the surface hardness cannot be measured accurately at the ridge of the cutting edge, the Vickers hardness (load: 300 g) at a position 0.05 mm inward from the honing surface in the polished cross section at 10 arbitrary points is measured. The surface hardness was measured to determine the maximum surface hardness. The results were shown in Tables 2 and 3 together with the internal hardness (Hv). In addition, for the cutting tips 1 to 13 of the present invention and the conventional cutting tips 1 to 13, work material: JIS S45C, a round bar with four longitudinal grooves at regular intervals in the longitudinal direction, cutting speed: 300 m / min, feed: 0. A high-speed intermittent cutting test of steel was performed under the conditions of 2 mm / rev, actual cutting depth: 1.5 mm, cutting time: 10 minutes, and the flank wear width of the cutting edge was measured. Tables 2 and 3 show the measurement results.

[0009]

[Table 1]

[0010]

[Table 2]

[0011]

[Table 3]

[0012]

From the results shown in Tables 2 and 3, all of the cutting tips 1 to 13 of the present invention have relatively high cutting edge ridges in the surface hardened layer constituting the cutting tips. The flank and rake surfaces with low hardness provide excellent wear resistance and chipping resistance, so that chipping does not occur even in high-speed interrupted cutting of steel, which is cutting under severe conditions. In contrast to the cutting performance, in the conventional cutting tips 1 to 13 in which the surface hardened layer does not change in relative hardness, in a relatively short time due to the high hardness of the flank and rake face in the surface hardened layer. It is evident that chipping occurs and extends the service life. As described above, the cutting tip of the present invention has Hv: 260 of the cutting edge ridge portion of the surface hardened layer constituting the cutting tip.
Excellent wear resistance is ensured by the maximum surface hardness of 0 to 3000, and the maximum surface hardness is Hv: 1800 to 22
Since the relatively hard flank and rake face of 00 have excellent chipping resistance,
For example, not only in high-speed continuous cutting of steel but also in high-speed intermittent cutting, chipping does not occur on the cutting edge, and excellent cutting performance is exhibited over a long period of time.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisashi Tsujizaki 1511 Furamagi, Ishishita-cho, Yuki-gun, Ibaraki Prefecture Inside the Tsukuba Works, Mitsubishi Materials Corporation (72) Inventor Katsuhisa Nonaka 1511 Furimagi, Ishishita-cho, Yuki-gun, Ibaraki Prefecture Address Mitsubishi Materials Corporation Tsukuba Works (56) References JP-A-3-32502 (JP, A) JP-A-2-15139 (JP, A) JP-A-63-57732 (JP, A) (58) Survey Field (Int. Cl. ⁷ , DB name) B23B 27/14 C22C 29/04

Claims (1)

(57) [Claims] The present invention contains 7 to 17% by weight of Co and / or Ni as a binder phase-forming component, and has an interior of 1400 to 1%.
The maximum surface hardness at the cutting edge ridge line where the flank of the cutting edge and the rake face intersect with the surface of a titanium carbonitride-based cermet throw-away type cutting tip having a Vickers hardness of 800 is 2600 to 3000 Vickers hardness. And a surface hardened layer having a Vickers hardness of 1800 to 2200 as the maximum surface hardness at the flank and rake faces, and having excellent wear resistance and chipping resistance. Cermet throwaway cutting insert.