JPH05239587A - Ticn-based cermet alloy - Google Patents

Abstract

PURPOSE:To obtain a TiCN-based cermet alloy having both high strength and high toughness by specifying the amts. of Ti, W and Mo and the ratio among them allowed to enter into solid soln. in a binding phase in a TiCN-based cermet alloy. CONSTITUTION:When a TiCN-based cermet alloy is produced by substituting one or more kinds of carbides or carbonitrides of groups IVa, Va and VIa metals other than Ti for part of TiCN as a base and carrying out bonding with an Fe family metal, the amts. of W, Mo and Ti allowed to enter into solid soln. in the binding phase are regulated so as to satisfy conditions represented by Ti+W+Mo>=6.0 and (W+Mo)/Ti>=1.0 in the case where the amt. of the binding phase is expressed as 100. The objective TiCN-based cermet alloy having remarkably improved heat resistance, especially toughness at high temp. while maintaining the same hardness is obtd.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The invention relates to titanium carbonitride (hereinafter referred to as "T
iCN ")-based cermet alloy, especially TiC that has both high strength and high toughness by strengthening the binder phase.
It relates to an N-based cermet alloy.

[0002]

2. Description of the Related Art At present, a nitrogen-containing titanium carbonitride (hereinafter referred to as TiCN) base alloy is mainly used as a cermet alloy for tools. This TiCN-based cermet alloy, compared to the conventional TiC-based cermet alloy and cemented carbide,
Room temperature strength, oxidation resistance, and cutting performance are improved.

Both of the TiCN-based cermet alloys have a core (TiW) C, (TiWTa) CN and surrounding structures ((TiWTa) C and (TiWTa) C, respectively.
The core phase particles of N form a hard phase to improve the strength, and the TiCN-based cermet alloy has a fine particle size due to the nitrogen content. Further, it is also known that the TiCN-based cermet alloy has excellent high temperature strength by solid solution of Zr, Hf, etc. in the double carbonitride.

[0005]

Problems to be Solved by the Invention As described above, TiC
N-based cermet alloys have superior characteristics in hard phase compared to TiC-based cermets and cemented carbides, but the binder phase is on the extension line of cemented carbide to improve wettability to Co, Ni, etc. To the extent that Mo is added or an intermetallic compound is dispersed. Therefore, we focused on the strengthening of the binder phase, especially the composition of the binder phase, and conducted studies to improve the strength, especially the heat resistance.

This heat resistance greatly affects the physical properties, especially the high temperature strength, and appears in the creep test, cutting test and the like. The creep test makes it difficult for plastic deformation to occur under high temperature and stress, and this phenomenon correlates with high-speed cutting to some extent. Therefore, an object of the present invention is to provide a TiCN-based cermet alloy that has particularly excellent hardness while improving the toughness at high temperatures by paying attention to the binder phase of the TiCN-based cermet alloy and measuring its strengthening.

[0007]

[Means for Solving the Problems] To strengthen the binder phase, Mo is used.
It is well known by those skilled in the art that it is easy to increase the solid solution amount of W. However, in the case of TiCN-based cermet alloy, W which has excellent heat resistance is used especially for applications corresponding to high speed cutting. If the amount of solid solution cannot be increased, heat resistance cannot be improved.

Therefore, the present inventor has substituted a part of a TICN-based carbide or carbonitride of the 4a, 5a, and 6a groups excluding Ti with one or two or more kinds, and bonding with a Fe group metal. In a TiCN-based cermet alloy consisting of the following, as a result of a detailed study on the use of carbide (WC), double carbide, and metal W as the W supply source for forming a solid solution in the binder phase, the solid solution amount of W in the binder phase In order to increase W, not only the solid solution amount of W in the binder phase increases, but W, Mo, Ti
It has been found that the binder phase is strengthened when it has a predetermined relationship with the solid solution amount of, and as a result, the strength, particularly the thermal strength, of the TiCN-based cermet alloy can be improved.

The present inventor has been made on the basis of this finding, and comprises a hard phase mainly composed of TiCN and a binder phase composed of Co, Ni, etc., and the Ti, W and Mo contents in the binder phase are 6.0. The TiCN-based cermet alloy is characterized by satisfying the condition of ≦ Ti + W + Mo 1.0 ≦ (W + Mo) / Ti. The reason for limiting the numerical values will be described in detail below.

In the present invention, the content of Ti, W and Mo in the binder phase is 6 wt% or more because it is the minimum amount necessary for strengthening the binder phase. Where Ti, W
And Mo content are% by weight in the binder phase,
ICP (inductive) which will be described in detail in the examples below.
y coupled plasma) optical emission spectrometry.

In order to have both excellent toughness and hardness, not only the total content of Ti and Mo in the binder phase is set within the above range, but also the W, Mo and Ti content ratio is 1.0≤W + Mo /
It is necessary to satisfy the Ti condition. This is because the toughness cannot be improved when the ratio is less than 1.0 as shown in Examples described later. The binder phase is mainly composed of one or two of Co and Ni, and contains Ti, W, Mo, Zr, Hf, which are the constituent elements of the hard phase, and unavoidable impurities as its strengthening elements.

[0012]

[Examples] The raw materials used for blending were commercially available TiCN powder (average particle size 1.0 μm) and WC powder (1.0 μm).
, TaC powder (1.0 μm in the same), and a solid solution of WC-TiC-TiN-TaC was prepared using the above powder. The solid solution is WC / TiC / TiN / Ta = 2/3
It was blended so as to be ⅔ / 2, dried and then subjected to solution treatment at 1600 ° C. for 2 hours in an N atmosphere to adjust the particle size to prepare a powder having an average particle size of 0.8 μm.

As shown in Table 1, these powders were mixed in various compositions, dried, and press-molded with a throw away tip of TEE433, sintered at 1500 ° C. for 1 hr in vacuum, and then processed into a predetermined shape. The solid solution was based on the amount of Ta, and Ti and W were added by using TiCN, TiC, TiN, WC, or the like.

Next, after polishing and lapping the above chips to confirm the physical properties, Vickers hardness, crack resistance (kg / mm) indicating toughness, solid solution amount of elements in the binder phase (dissolved amount in the binder phase, It was calculated as 100%). Vickers hardness is 3 with diamond indenter according to JIS standard
A load of 0 kg was applied and the diagonal length was measured and determined from the hardness conversion table. The crack resistance (kg / mm) is determined by applying a load of 50 kg with a diamond indenter as in the Vickers hardness and measuring the distance of cracks generated at the four corners of the indentation.
It was calculated by summing the lengths of cracks.

The amount of elemental solid solution in the binder phase is determined by dissolving and extracting the binder phase with an aqueous mixed acid solution, and measuring ICP (inductively).
It was determined by quantifying each element in the binding phase by coupled plasma emission spectrometry. Table 2 shows Vickers hardness and toughness, crack resistance (kg / mm),
Ti + W + Mo content (wt%) in binder phase, Mo + W / T
indicates i. Further, a test was conducted according to the following cutting specifications. Cutting speed 200 m / min Feed 0.08 mm / blade Cutting 1.0 mm Work material SCM440 Tip shape TEE433 Cutter shape φ80 1-blade The results are shown in Table 3. In the cutting test, the amount of wear and the time required to reach chipping from the thermal crack generated by the heat cycle during cutting were measured.

[0016]

[Table 1] Sample number TiC TiN WC TaC Mo Co Co Ni Present invention example 1 27.0 27.0 21.0 10.0-7.5 7.5 Present invention example 2 27.0 27.0 19.0 10.0 2.0 7.5 7.5 Present invention example 3 27.0 27.0 16.0 10.0 5.0 7.5 7.5 Present invention example 4 40.5 13.5 16.0 10.0 5.0 7.5 7.5 Inventive Example 5 40.5 13.5 16.0 10.0 5.0 7.5 7.5 Comparative Example 6 35.0 35.0-10.0 5.0 7.5 7.5

[0017]

[Table 2] Bonded phase distribution (WT%) of the sample number Cermet W + Mo Ti + Mo + W (W + Mo) / Ti hardness Crack resistance Ti W Mo Co Ni Hv Kg / mm 1 3.0 3.5-46 bal 3.5 6.5 1.1 1420 105 2 3.2 2.3 4.4 45 bal 5.5 9.9 3.1 1460 102 3 2.3 1.7 6.0 45 bal 4.0 10.0 1.7 1460 110 4 1.2 1.5 5.5 46 bal 7.0 8.2 5.8 1490 113 5 1.2 1.0 4.8 46 bal 5.8 7.0 4.8 1490 102 6 1.0-4.0 47 bal 5.0 7.0 2.5 1410 105

[0018]

[Table 3] Trial No. Cutting time (min) Maximum flank wear amount Remarks 1 45 0.38 2 40 0.29 3 45 0.31 4 50 0.32 5 38 0.38 6 20 0.05 Cutting edge removal Yes

From the results of Table 3, in the comparative cermet, after chipping occurred, chipping occurred and the life reached.
In the cermet of the present invention, similar to the cemented carbide P system,
It was possible to cut even if a thermal fatigue crack occurred without causing defects. In addition, in these cutting tests, the examples of the present invention were less prone to chipping, so that a longer life was achieved.

[0020]

As described above, the TiCN-based cermet alloy according to the present invention has the same hardness and heat resistance by specifying the solid solution amounts of Ti, W and Mo in the binder phase and their ratios. In particular, a TiCN-based cermet alloy with significantly improved toughness at high temperatures could be obtained, and excellent performance was exhibited in cutting.

Front Page Continuation (72) Inventor Susumu Toyota Susumu Narita, Chiba Prefecture 2 13 Narita Factory Hitachi Tool Co., Ltd. (72) Inventor Akio Washi 13 Narita Chiba Prefecture 2 Niizumi Hitachi Tool Co., Ltd. Narita Factory

Claims (1)

[Claims] 1. TiC based on TiCN, part of which is replaced by one or more of 4a, 5a, and 6a carbides or carbonitrides other than Ti, and bonded with an Fe group metal.
In an N-based cermet alloy, W dissolved in the binder phase,
A TiCN-based cermet alloy, characterized in that the solid solution amounts of Mo and Ti satisfy the condition of 6.0 ≦ Ti + W + Mo 1.0 ≦ (W + Mo) / Ti when the binder phase is 100.