JPS6056778B2 - Bare metal for coated hard alloys - Google Patents

Description

Detailed Description of the Invention: A so-called superstructure consisting of a hard phase of one or more of carbides, nitrides, and carbonitrides of group elements a, a, a, and a, and a binder phase mainly composed of iron group metals. It is well known that coated cemented carbide tools, in which a hard metal is coated with one or more of carbides, nitrides, carbonitrides and/or oxides, have particularly excellent wear resistance.

Above all, TiC,. Ti(CN), TlN. ．． Al
It is known that a coated cemented carbide coated with 5 to 10 microns of one or more types of 2O3 has a lifespan of 2 to 1 mm longer than conventional cemented carbide. However, these coated cemented carbides have various problems because they use base metals with a bonding phase of iron group metals, especially CO, and it is difficult to say that the properties of the coated phase are fully utilized. It has been found that the characteristics required in a tool can be roughly divided into two types.

That is, toughness and wear resistance. As for toughness, it has been found through many years of research by the inventors that it can be further divided into two types. These include mechanical strength and thermal fatigue strength. The relationship between mechanical strength and wear resistance is contradictory in the above-mentioned superalloys, and if the iron group binding metal (CO in many cases) is increased and the mechanical strength is increased, the wear resistance is decreased. Put it away.

Changes in thermal fatigue strength are quite complex.

Thermal fatigue strength increases as the amount of CO increases;
If the amount of O is too large, plastic deformation will occur, leading to a decrease in thermal fatigue strength. Therefore, there is naturally a limit to the improvement in thermal fatigue strength by increasing the amount of CO. On the other hand, in order to improve the efficiency of cutting tools, tools with high thermal fatigue resistance and high labor strength are required to withstand heavy cutting with large depths of cut and feed.
In this case, although particularly high toughness is required, plastic deformation resistance is also required, and current cemented carbide metals naturally have their limits. The present invention combines abrasion resistance and toughness by coating a base metal with a hard material, which has plastic deformation resistance and thermal fatigue toughness under high temperatures that conventional cemented carbide cannot achieve. We propose a tool with excellent performance.

In conventional cemented carbide with CO as a binder phase, the softening temperature of the CO phase is low, so the plastic deformation resistance at high temperatures is already a problem under practical cutting conditions, and the thermal fatigue toughness of the materials described below is low. Comparatively low.

Plastic deformation is also important in coated cemented carbide tools in another sense.

This is because even if the cutting edge becomes hot during cutting and the cemented carbide metal is plastically deformed, the coating hard phase hardly undergoes plastic deformation in that temperature range, so the coating can follow the deformation of the metal. This causes breakage or peeling of the coating, shortening tool life. Therefore, in order to prevent this, it is necessary to use high melting point metals such as W instead of iron group metals. In fact, prototype alloys based on this idea require 2 to 3
Tl-
Using the eutectic point of the W-C system, (Ti,.W)C1? x-
It has been proposed to create a W alloy by heating and melting it to a temperature of around 2500 points C and casting it using a so-called melting method. Although the wear resistance and plastic deformation resistance at high temperatures of this alloy (hereinafter referred to as cast alloy) are far superior to that of the cemented carbide, it has the following drawbacks that prevent it from being widely used: I couldn't reach it.

First, the toughness, especially the mechanical strength, is extremely poor. Second
However, since it is made by casting, products with complex shapes such as cemented carbide manufactured by powder metallurgy cannot be manufactured at low cost. Thirdly, due to the casting temperature, only alloys with low melting points near eutectic compositions can be obtained. Also, (Tl..W) (C.
．． Although N)-W casting alloys have been proposed, they have not been put to practical use for similar reasons. Therefore, those skilled in the art can easily think that if the composition of these cast alloys can be manufactured by powder metallurgy, the second and third of the above-mentioned drawbacks can be overcome.

However, although many attempts have been made to achieve this goal, no superior alloy has actually been created. The reason is that alloys with this composition contain carbides and MO. This is because since it is made of a high melting point metal such as W, its sinterability is extremely poor and it does not have sufficient strength. The present inventors have conducted detailed research on these alloys, particularly on the elements that form the hard phase, and have obtained surprising findings.

In other words, they discovered that by adding oxygen to the hard phase, which was conventionally thought to inhibit sintering in hard alloys, sinterability was significantly improved, and toughness was also improved. .

Based on this knowledge, the present invention proposes a high melting point metal binder hard alloy with excellent toughness as a tool that meets the recent demands for higher efficiency. The main feature of the present invention is that oxygen is actively introduced into the hard phase, but in this alloy, almost no oxygen is needed outside of the hard phase, and the hard phase is (
M1, M2) (C1-010x)2 (hereinafter referred to as formula (1)) or (M1, M2) (C1-o-, 00..
Ny)2 (hereinafter referred to as formula (2)).

M1 is Ti. ．． Zr. ．． M2 is one or more metals selected from Hf, and M2 is CrlMO. ．． One or more metals selected from w. This is clear from the X-ray diffraction shown in FIG. This figure shows W5O atomic% and Ti25 atomic%.
This is an X-ray diffraction pattern of the alloy of the present invention with a composition of The same is true for alloys containing N. The limiting conditions of equations (1) and (2) will now be explained.

First, if the oxygen content, X, is too small, its effect will not be apparent, and if it is too large, the sinterability will be deteriorated. Generally, the sinterability of mixtures of oxides and metals is poor because of poor wetting of their interfaces, and the same can be considered for the alloys of the present invention. If the range is 0.05≦x≦0.5, a high-strength alloy can be obtained without impairing the effect of oxygen addition.

The same thing can be said about nitrogen, but if the lowest wear resistance is required, nitrogen may be undesirable, so 0.01≦y≦0.5 is considered to be appropriate. Furthermore, if the sum of N and O (x+y) exceeds a limit, sinterability will be impaired.

Since the content of O is required to be 0.05 or more, the lower limit is also determined, and it is desirable that 0.05≦x+y≦0.6.
If the stoichiometric constant z exceeds 0.5, the hard phase and carbon coexist, which is outside the scope of the present invention.

Moreover, if it is less than 0.1, the hard phase is too small and the hardness is insufficient, which deviates from the purpose of the present invention as a cutting tool or wear-resistant material. Therefore, it is necessary that 0.1≦z≦0.5. ■ Some of the group a elements are V. Nb. Substitution with Ta(7)Va group element is effective in improving toughness.

However, if a large amount is added, the structure tends to deviate from the coexistence of Me (CNO) and high melting point metal phase, which is characteristically produced by the combination of high melting point elements of groups 1a and 2a. (Ml
a. ．． M2b. ．． M3c) (C1-o-,, NylOX
) 2 (M1■a-group element, M2■a-group element, M
3) A group element) a+c is preferably within the range of the amount of the A group element, preferably between 0.1 and 0.7, and ± is 0.3a
It is desirable that it is below +c.

That is, up to 30 atom % of Mla is V. It is preferable to substitute one or more group ①a metals selected from sNb, Ta. Note that no effect is observed if the amount of substitution is less than 1 atomic %. Iron group metals and Ag. ．． Pd. ．． It is generally known that the addition of a small amount of Cu or the like promotes the sinterability of high melting point metals, and this effect is also observed in the alloy of the present invention.

It is preferable to add one or more of these metals, as this enables sintering at a lower temperature. However, these metals have low melting points, and it is clear that if they are added in large amounts, the heat resistance, which is a characteristic of the present alloy, will be reduced. From this point of view, it is desirable to reduce the amount of these metals added to 2 atomic % or less. Note that no effect is observed at 0.01 atomic % or less. Carbides, nitrides,
For example, TlClTi may be used as a coating material in a single layer or in multiple layers of oxides, borides, or mixtures or compounds.
N. Coating with Tl(CN), AI2O3, etc. results in a tool that can withstand high-efficiency cutting compared to conventional coated cemented carbide base metals.

This will be described in Examples. It should be noted that the coating method that is effective in the present invention is not limited to the coating method shown in the Examples, and the coating material is not limited to the one shown in the Examples. Example 1 86% by weight of W powder with an average particle size of 1 μm and 14% by weight of TLC powder with an average particle size of 1 μm were wet mixed and subjected to a drying process to form SN.
G844 (width 25.4=, thickness 6.4?, cutting edge radius 1.
6).

This was sintered as follows. Room temperature to 1000℃ Vacuum (3×10-1T0rr or less) 1000 to 17000
CPc0350T0rr1700~18500C vacuum (
1 x 10-1T0rr or less) Maintained at 18500C for 1 hour Cooling was done in vacuum, heating rate was 100CImin When the carbon and oxygen contents of the resulting alloy were measured, they were 2.4% by weight and 0.5% by weight, respectively. It was hot.

This Yumisaki Otsu)? The composition of this prototype alloy is or (TlO.3
3) WO◆67) (CO●81~00●19) O●37
It is represented by ヰ. This was deposited to 5 μm using a known chemical vapor deposition method.
The TiC film was coated with a TiC film, and the following cutting test was conducted.

Work material: S43C forged material, outer diameter 220wn, length 15
0h Speed: 110rr1.1min Depth of cut: 6-10Tn Feed: 0.86wnIrev Table 1 shows the lifespan of the present invention and comparative products.

In this test, the cutting depth fluctuated rapidly due to the highly uneven forged material, and the cemented carbide reached the end of its life in a short period of time.

Furthermore, conventionally coated chips undergo plastic deformation due to high feed rate, leading to breakage. In addition, metals that do not contain oxygen have low strength and fail due to fatigue.

On the other hand, the product of the present invention had a longer life than the commercially available cast alloy, and a stable machined surface was obtained. Example 2 An alloy of W42-Ti28-C25-σ was prepared in the same manner as in Example 1, various coatings were applied, and comparisons were made by the following cutting tests.

Table 2 shows the results. Work material: SCM4 (HB28O)
80φ×400e Speed: 1407TLImin Depth of cut: 27077! Feed rate: 0.36TwtIrev Tip shape: SNG432 Bite holder NiNllR-44 has significant crater wear, and with conventional coated tips, crater wear progresses significantly after the coating film has worn off.

Since the ingot of the present invention has extremely good wear resistance, its life does not end due to crater wear. Example 3 An alloy having the composition shown in Table 3 was used as a base metal and coated with 2μ of TlC, 2μ of Ti(CN), and 2μ of TiN by chemical vapor deposition.

This was subjected to a milling test under the following conditions. The results are shown in Table 3. Workpiece material: SCM3 (width 600mm, length 100077!77! plate material) Speed: 807TLImjn Depth of cut: 6T1r1n Feed length 0.54Tnm/Blade tool shape: Axial rake 4730" Radial rake -1 key 30" Lead angle 251 19.05707! Cutting time: 3 powders Commercially available TiC-coated tips break the coating film during heavy intermittent milling, which causes chips and shortens the service life. Since cracks do not progress to the extent that they lead to defects due to breakage, the coating film can bring out its good wear resistance.

As described above, the present invention can fully utilize the excellent performance of the coating film due to the high base metal toughness. Example 4 W55-Tl2O-Cl6-N4-0 as in Example 1
5 or (TlO-27)WO・73)(CO・64)N
A sample of 0◆33 was prepared.

This was coated with 6 μm of TiC by chemical vapor deposition (CVDl plasma CVD) and physical vapor deposition (ion blating), and a planer processing test was conducted. Work material: SS4l
Speed: 257T1, Imin Maximum depth of cut: 1.57T$t Cutting width: 15wn Rake angle: 15n In cutting as in this example, the cemented carbide is damaged and becomes useless.

The product of the present invention has toughness not found in cemented carbide, and is more wear resistant than high speed steel. From the above four examples, it is clear that the present invention has much better performance than conventional cemented carbide base metal coated alloys.

[Brief explanation of the drawing]

Figure 1 shows W5O atomic%, Tj25 atomic%, C2O atomic%
, shows an X-ray diffraction pattern of an alloy of the present invention having a composition of 1 atomic %. 1... Peak of W, 2... Peak of TiC phase.

Claims (1)

[Claims] 1 Consists of a hard phase and a high melting point metal phase, and the entire composition is expressed by the formula (1
) A coated hard alloy ingot characterized by: (M_1a, M_2b) (C_1_-_x, O_x)_
z... (1) However, M_1 is a group IVa metal, and T
One or more selected from i, Zr, Hf, M
_2 is a group IVa metal and is composed of one or more selected from Cr, Mo, and W. Here, a, b, x, and z all have an atomic ratio of a+b=1, and 0.1≦a≦0.7. 0.05≦X≦0.5, 0.1≦z≦0.5. 2 Consists of a hard phase and a high melting point metal phase, and the total composition is expressed by the formula (2
) A coated hard alloy ingot characterized by: (M_1a, M_2b) (C_1_-_x_-_y, N
_y, O_x)_z...(2) However, M_1 is
M_2 is a group IVa metal, one or more selected from Ti, Zr, and Hf, and M_2 is a group IVa metal, including Cr, Mo, W
Consisting of one or more selected types. Here, a, b, x, y, z are all atomic ratios, a+b=
1, and 0.1≦a≦0.7. Also 0.05≦x
+y≦0.6, 0.05≦x≦0.5, 0.01≦y≦
0.5, 0.1≦z≦0.5. 3 It consists of a hard phase and a high melting point metal phase, and the total composition is expressed by the formula (3
) A coated hard alloy ingot characterized by: (M_1a, M_2b) (C_1_-_x, O_x)_
z...(3) However, M_1 is a group IVa metal, and T
One or more selected from i, Zr, Hf, M
_2 is a group IVa metal, and is one or more selected from Cr, Mo, and W, and 1 to 30 atomic percent of M_1 is one or two of group Va metals such as V, Nb, and Ta. The above metals are substituted. Here, a, b, x, and z all have an atomic ratio of a+b=1 and 0.1≦a≦0.7. 0.05≦x≦0.5, and 0.1≦z≦0.5. 4 Consists of a hard phase and a high melting point metal phase, and the total composition is expressed by the formula (4
) A coated hard alloy ingot characterized by: (M_1a, M_2b) (C_1_-_x_-_y, N
_y, O_x)_z...(4) However, M_1 is
M_2 is a group IVa metal, one or more selected from Ti, Zr, and Hf, and M_2 is a group IVa metal, including Cr, Mo, W
1 to 30 atomic % of M_1 is substituted with one or more metals selected from Va group metals such as V, Nb, and Ta. Here, a, b, x, y, z are all atomic ratios, a+b=
1 and 0.1≦a≦0.7. Also, 0.05≦x+y≦
0.6, 0.05≦x≦0.5, 0.01≦y≦0.5
and 0.1≦z≦0.5.