JPS5839221B2 - Sintered hard alloy and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sintered hard alloy whose cutting characteristics are significantly improved by incorporating oxygen into the sintered hard alloy whose main component is Ti.

Conventionally, it has been common knowledge that when a large amount of oxygen is contained, sinterability is poor, fine pores are generated in the alloy, and the toughness of the alloy is poor.

Of fenlegungsschr
if t) 2043411, the amount of oxygen in the alloy is 0.
．． It is stated that the amount should be kept to 15% or less as much as possible.

Also, “Modified 5pinoda” by Rudy et al.
lAI Joys for Tool and Wea
r Appl 1cations.

8th Plansee Sem1nar II (1
974) Even if oxygen is contained up to 2.5% by weight, the sinterability is not bad, but the transverse rupture strength becomes low, and the α' phase (carbonitrided homogeneous phase with little Mo), α “phase (carbonitriding homogeneous phase with a large amount of Mo), the weight φ0 is 0.5 and 0.9, respectively.
It has been reported that a dense phase cannot be obtained with 2 or more.

The feature of Rudy et al.'s method is that carbonitride alloy powder (TiMo
) (CN) is used as a raw material.

Although this is a slight improvement over the conventional method, the essential phenomenon of releasing the oxygen contained therein remains the same, resulting in a decrease in toughness.

As mentioned above, even if oxygen is included in Rudy et al.'s method, the oxygen in the alloy is not stable and tends to be released as CO2CO2 gas, resulting in poor alloy tension. We are striving to

The inventors have a completely different opinion and have discovered a production method that allows oxygen to be stably contained.

According to this method, it was found that the sintered hard alloy of the present invention containing oxygen has significantly improved performance compared to an alloy that does not contain oxygen, contrary to conventional wisdom.

The method of the present invention uses TiO which is a Bl type solid solution (the Bl type solid solution is a NaCA type solid solution type tank solution structure compound) as a raw material.
, Ti(CO), Ti(No), Ti(CNO) (for convenience, Tie, Ti(CO), Ti(NO), Ti(CN
Displayed as 0), actually Ti10. As is clear from the phase diagram, the C and N ratios fluctuate.

(Similarly hereinafter) It is characterized by using a powder or a raw material in which up to 50 mol of Ti is replaced with a group IVa metal or a group VIa metal, and/or by using a CO gas atmosphere as the sintering atmosphere.

By using such a manufacturing method, it has become possible to create an alloy with significantly improved plastic deformation resistance and crater resistance at high temperatures.

The reason for this is not clear, but when comparing the properties of TiC and TiO, the Vickers hardness at room temperature is lower than that of TiC and TiO.
iO 3200 kg/mJ, i 700 kg/
mA, TiC has high hardness at room temperature, and at 800°C, TiC and TiO each have a hardness of 500 kg/mA.

At 660 kg/mm, the hardness of TiO increases as the temperature increases.

Furthermore, TiO has far more chemically stable properties than TiC.

Therefore, if it becomes possible to incorporate oxygen into the alloy, T
An alloy that takes advantage of the properties of iO can be obtained.

Furthermore, if oxygen is contained in the alloy, the alloy surface reacts with oxygen during cutting, and Belag is likely to be formed on the surface, which may reduce the cutting resistance.

The above materials use TiO and Ti(CO) as raw materials.

Although Ti (CNO) and Ti (NO) powder are used,
Ti may be replaced with IVa group metal or Va group metal up to 50 mol φ, but if the mol ratio exceeds 50 mol, undissolved material will remain.

A material in which Ti is replaced with a group VIa metal cannot be used as a raw material.

For example, when using (T i MO') (CNO) powder, the more MO there is, the more unstable the oxygen in the solid solution becomes, and the more likely it is to be released as C09C02 gas, which causes the formation of fine pores in the alloy. Although the resultant toughness decreases, gas is not released when the lVa group metal and/or the VIa group metal are in solid solution as in the case of the method of the present invention, and especially when N and O coexist. and oxygen easily form a stable solid solution.

Next, limitations on the metal components and non-metal components of the hard phase of the present invention will be described.

The total composition of the hard phase of the present invention is ((Group 1 Va metal) a (
Group VIa metal) b) (CuNvOw)z,
The first Va group metal represents one of Ti, Zr, and Hf, or two or more metals in an arbitrary ratio.

Further, the Group VIa metal refers to one of Cr, Mo, and W, or two or more metals in an arbitrary ratio.

Up to 60 moles of each of these Group I Va metals and/or Group VIa metals can be replaced by a metal selected from the group consisting of V, Nb, and Ta.

When it exceeds 60 mol φ, wear resistance deteriorates.

In addition, 20 or more moles of the metal component of the hard phase is Ti, Zr and Hf are effective in improving wear resistance, V, Nb and Ta are effective in improving toughness, Cr is effective in improving corrosion resistance, and MO2W is effective in improving toughness.

Next, let us discuss the nonmetallic components of the hard phase.

v and w are the molar fractions of carbon, nitrogen, and oxygen, respectively,
If (2) is less than 0.04, the effect of nitrogen to refine the alloy and the effect of stably containing oxygen is lost, and if (2) is more than 0.36, sinterability deteriorates.

Further, when W is 0.01 or less, there is no effect of oxygen inclusion, and when W is 0.20 or more, sinterability deteriorates.

2 is the stoichiometric parameter for metals (1st Va group metal 10th V
Group Ia metal) The number of bonds of carbon, nitrogen and oxygen duram atoms per duram atom, from 0.80 to 1.0
It fluctuates between 5 and 5.

Below 0.80, a brittle phase exists, and above i, o, F
ree Carbon exists, but there is no performance problem up to 1.05.

The range of the total composition of the hard phase of the present invention is shown in FIGS. 1 and 2.

In FIG. 1, the scope of the present invention is within the area surrounded by A, B, C, and D, but preferably a more limited area A'
, B, C', D'.

If W is 0.20 or more, sinterability will be impaired, and if it is less than o or oi, there will be no effect of containing oxygen.

If b is 0.04 or less, the toughness will deteriorate, and if b is 0.5 or more, the wear resistance will deteriorate.

In FIG. 2, the scope of the present invention is within the area surrounded by E, F, G, and H, but preferably a further limited area E'
, F, G', and H'.

When N10-1-N is 0.42 or more, sinterability is impaired;
Below 0.04, the effect of nitrogen disappears, and b is 0.04.
When b is less than 0.50, the toughness deteriorates, and when b is 0.50 or more, the wear resistance deteriorates.

The metal bonding phase that binds the hard phase is composed of iron group metals,
This contains one or more of Al, Cu, Ag, Si, and B in a weight ratio of 0.2 to 25% relative to the iron group metal, but if the content is less than 0.2 fO, the alloy becomes brittle and sufficient bonding is not achieved. No effect can be obtained, and if the weight ratio is 25 or more, the wear resistance will decrease.

The iron group metal is selected from Co p N + + Fe, but the effect of the present invention can be maintained even if it is added in a small amount of 5 weight φ or less by replacing it.

In other words, the addition of L has the effect of contributing to strengthening the binder phase, and C
Addition of u suppresses grain growth and improves thermal conductivity.

It also works to make the surface and internal structure uniform.

Addition of Ag improves wettability and can also be expected to improve thermal conductivity.

Si and B also contribute to improving sinterability. In addition, the metal bonding phase includes Ti, Zr, Hf, V, and Nb.

It is a matter of course that hard phase forming elements such as Ta, Cr, Mo, W, C, N, and 0 are contained.

As described above, the present invention uses oxides, carbonates,
CO gas sintering is performed as a sintering method using oxynitrides and carbonate nitrides to prevent deoxidation and/or enrich oxygen, but 2 powders that do not contain oxygen are sintered with CO gas. Oxygen can also be incorporated into the alloy.

Also, the reason why the CO gas pressure was set in the range of 0.01 to 300 Torr is that below 0.01 Torr, oxygen becomes CO2CO2.
This is because carbon is more likely to be released as a gas, and if the temperature exceeds 300 Torr, carburization becomes severe and fluctuations in the carbon content become large.

Applications of the alloy of the present invention are not limited to those described in the examples, and can be used not only for cutting tools but also for pen balls, wear-resistant tools, dies, wear-resistant parts (apex seals), ornaments, etc.

Example 1゜Ti(CNO) powder prepared from commercially available TiC powder, TiN powder, WC powder, Mo2C powder, TiO powder, TiO powder, TiC powder, and TiN powder, as well as Ni powder, C
o powder, Al powder, Cu powder, Ag powder, TaN powder,
TaC powder was blended with the composition shown in Table 1 to obtain the hard phase composition shown in Table 2.

Acetone was added to this using a 188 stainless steel lined pot using a TiC--Ni--Mo pole with a diameter of 10 mm, and the mixture was mixed in a wet ball mill for 96 hours.

To this mixed powder, add 3 types of camphor and add 2t/i
Embossed with.

This stamped body was maintained at a CO gas partial pressure of 5 Torr from 800°C to 1380°C, then baked at 1380°C for 60 minutes under vacuum, and when cooled to 800°C, the CO gas partial pressure was 5 Torr.
The alloy was prepared by holding at Torr.

Table 3 shows the mechanical properties and analyzed oxygen content of the obtained alloy.

Further, the cutting performance is shown in Table 4. EXAMPLE 2 Table 5 below is a composite of a number of tooling hard phases formed from compositions combining several alloy substitutes.

Table 6 shows the mechanical properties of the obtained alloy, and Table 7 shows the cutting performance.

[Brief explanation of the drawing]

Figure 1 shows the total composition of the hard phase ((IVa group metal)a(VI
When expressed as group a metal)b)(CuNvOw)z,
The vertical axis shows the molar fraction W of oxygen, and the horizontal axis shows the molar fraction W of group IVa metal. Figure 2 shows the total composition of the hard phase ((IVa group metal)a(VI
When expressed as group a metal)b)(CuNvOw)z, the vertical axis shows N10-)-N and the horizontal axis shows the mole fraction of group VIa metal.

Claims (1)

[Claims] An alloy consisting of an I Bl type solid solution hard phase and a metal binder phase, in which IVa is used as a metal component to form the hard phase.
It has a group metal (one or more types including Ti) and a group VIa metal (one or more types of W t Mo t Cr), the nonmetallic components are C, N, and O, and it has a hard phase. If the total composition of the hard phase is within the regions A, B, CD1 in Figure 1 and the regions E, F, G, H in Figure 2, and the total composition of the hard phase is in the atomic ratio ((Group 1 Va metal) ) a (Group VIa metal) b ) (CuNvOw) z, a t
a+b=1.0.5 between b r u s V t W
≦a≦0.96, 0.04≦b≦0.50u + v
There is a relationship of + w = 1, and the range of u, v, w, z is 0.49≦U≦0.95 0.04<v<0.36 0.01≦W≦0.20 0.80≦ 2≦1.05, and furthermore, the metal alloy is a metal containing one or more of iron group metals [τ, A#, Cu, AgSi, B, and the entire alloy is 10
When the weight width is 0, the amount of bonded metal in this range is 3~
25 weight φ, and each of Group 1 Va metal and/or Group VIa metal in the hard phase of the above alloy from 1 mol to 60 mol is replaced by a metal selected from the group consisting of V, Nb, and Ta. A sintered hard alloy characterized by: 2 As a bonding metal, A7. Cu. One or more types of Ag, Si, and B are 0 for iron group metals.
．． The sintered hard alloy according to claim 1, wherein the sintered hard alloy has a weight ratio of 2 to 25%. 3. Preventing deoxidation of the alloy and/or by maintaining the CO gas partial pressure at 0.01 to 300 Torr intermittently or continuously during part or all of the heating, sintering, and cooling processes. Alternatively, an alloy consisting of a Bl-type solid solution hard phase and a metal binder phase characterized by oxygen enrichment to contain oxygen in the alloy, in which group IVa metal (Ti) is used as a metal component to form the hard phase. 1 or 2 or more of group a metals (including 1 or 2 of W, Mo, and Cr)
The nonmetallic components are C, N, and O, and the total composition of the hard phase is within the regions A, B, and C2D1 in Fig. 1 and the regions E, F, G, and H in Fig. 2. Moreover, the total composition of the hard phase is ((Group 1 Va metal) a
(Group VIa metal) b) (CuNvOw) When expressed as z, a+b=1.0.5≦a between a, b, u, ■2w
≦0.96, 0.04≦b≦0.5゜u + v +
There is a relationship w = 1, and the range of u, v, w, z is 0
．． 49<u<0.95 0.04<:y<0.36 0.01≦W≦0.20 0.80≦2≦1.05, and furthermore, the metal binding phase mainly contains iron group metals, Al, Cu, Ag. One or more types of Si and B are 0.2 to 25 of iron group metals.
A metal containing a weight φ, the entire alloy being io. When considering the weight range, the amount of bonded metal in this is 3 to 2
5 by weight and each mole of Group I Va and/or Group VIa metal in the hard phase of the above alloy φ to 60
A method for producing a sintered hard alloy, characterized in that up to the mole content is replaced with a metal selected from the group consisting of V, Nb, and Ta. 4 Along with carbides and nitrides, Ti0h (0,8≦h≦1
．． 5), Ti (Ce, Og)i (0,05≦e≦
0.95゜0.05≦g≦0.95, 0.80≦i≦
1.5), Ti(Nj, Ok M (0,05≦j≦
0.95, 0.05≦≦0.95, 0.80≦l
≦1.5), Ti (Cm. Nn, Oo)p (0,05'nm≦0.95,
0.05≦nζ0.95, 0.05≦O≦0.95
, o, s i p≦1,5) and sintering the mixture to make the alloy contain oxygen. . 5 Ti is one or two of lVa group metal, VIa group metal
4. The method for producing a sintered hard alloy according to claim 3, using a raw material in which at least one species has been substituted by 1 mol φ to 50 mol φ.