JPH0121113B2 - - Google Patents

Description

[Detailed description of the invention]

This invention has excellent toughness and wear resistance,
The present invention relates to a composite ultra-high pressure sintered piece suitable for use as a cutting blade, particularly when cutting difficult-to-cut materials. Conventionally, for cutting high-hardness steel, Ni-based and Co-based superalloys, etc., tantalum nitride (hereinafter referred to as TaN): 10 to 20% by weight (hereinafter % indicates weight %),
The remainder consists of cubic boron nitride (hereinafter referred to as CBN) and unavoidable impurities.
The cutting edge layer of CBN-based ultra-high pressure sintered material contains one or more of Fe, Co, and Ni: 1 to 10% for the purpose of imparting toughness to it, and the rest is carbonized. WC with a composition consisting of tungsten (hereinafter referred to as WC) and unavoidable impurities
A composite ultra-high pressure sintered piece made of a laminated composite with a retaining layer of base cemented carbide is used as the cutting edge. The above conventional composite ultra-high pressure sintered piece has normal pressure:
It is manufactured under ultra-high pressure sintering conditions of 50,000 to 60,000 atm and temperature: 1350 to 1500°C, so the WC-based cemented carbide forming the retaining layer is liquid phase sintered. In the retaining layer of such conventional composite ultra-high pressure sintered pieces, a considerable amount of WC is dissolved in the liquid phase (usually composed of Co) under high temperature and pressure during its manufacture, while a proportionate amount of WC is dissolved in the liquid phase (usually composed of Co). As a result, the precipitation of WC becomes more active during solidification, so the precipitated WC grains grow abnormally long and thin, and furthermore, at the interface between the cutting edge layer and the retaining layer, the CBN constituting the cutting edge layer The formation of pores (small holes) caused by the nitrogen gas generated by the decomposition could not be avoided, and as a result, the interfacial bonding strength between both layers was significantly reduced. In conventional composite ultra-high-pressure sintered pieces in which the adhesion between the cutting edge layer and the retaining layer is not good, minute vibrations during cutting are amplified, accelerating the wear of the cutting edge and causing chipping. This made it more likely that defects would occur. From the above-mentioned viewpoints, the present inventors have developed a composite ultra-high pressure sintered piece for cutting blades that has high interfacial bonding strength with the CBN-based ultra-high pressure sintered material constituting the cutting edge layer having the above composition, and further As a result of conducting various studies to obtain a material for forming a retaining layer with excellent toughness and wear resistance, we found that (a) the above material for forming a retaining layer was replaced with titanium nitride (hereinafter referred to as titanium nitride).
When composed of a base ultra-high pressure sintered material (denoted as TiN),
Grain growth during sintering is extremely small and CBN
It is possible to obtain a composite ultra-high pressure sintered piece in which the generation of pores at the interface between the cutting edge layer and the cutting edge layer made of TaN is suppressed, and the bonding strength with the cutting edge layer is extremely high. (b) The above-mentioned TiN is inexpensive, has excellent heat and wear resistance, and has the property of strongly bonding with Fe group (Fe, Co, Ni) metals. When the binder phase forming component for TiN, which is the dispersed phase forming component in the layer, is composed of an Fe group metal, the resulting retaining layer has high thermal conductivity and a low coefficient of friction, so it seems to have excellent thermoplastic deformation resistance. This results in excellent wear resistance and chipping resistance during cutting. (c) In the above retaining layer, as a dispersed phase forming component.
In addition to TiN, one or more of the nitrides of V, Ta, Nb, Zr, and Hf are added, and in addition to Fe group metals, one of Cr, Mo, and W is used as a binder phase forming component. When one or more species are contained, grain growth and pore generation are further suppressed, and the bonding strength between the dispersed phase and the binder phase is further improved. In this case, the effect brought about by the nitride other than TiN is the same whether it exists in the form of a simple substance or in the form of a composite solid solution with TiN. The findings shown in (a) to (c) above were obtained. Therefore, this invention has been made based on the above knowledge, and includes a composite ultra-high pressure sintered piece for cutting blades containing TaN: 10 to 20%, and the remainder consisting of CBN and inevitable impurities. A cutting edge layer of a CBN-based ultra-high pressure sintered material having the composition: TiN: 50-95%, one or more of nitrides of V, Ta, Nb, Zr, and Hf: 1-20% , or two or more: 1 to 20%, one or more of Cr, Mo, and W: 1 to 20%, and the remainder is one of Fe, Co, and Ni
It is characterized in that it is composed of a laminated composite of a seed or two or more kinds and a holding layer of a TiN-based ultra-high pressure sintered material having a composition consisting of unavoidable impurities. The reason why the component composition of the retaining layer in the composite ultra-high pressure sintered piece of the present invention is limited as described above will be explained below. (a) TiN If the TiN content is less than 50%, the heat resistance strength will decrease, while if the TiN content exceeds 95%, the toughness will decrease.
It was set at ~95%. (b) Nitride other than TiN If the content is less than 1%, the desired effect of suppressing grain growth and pore generation of the dispersed phase and improving wettability with the binder phase cannot be obtained, while if the content exceeds 20% Since this would impair the effect of improving these properties, the content was set at 1 to 20%. (c) Cr, Mo, W These components are dissolved in relatively large amounts in the Fe group metal constituting the binder phase, further improving the heat resistance strength of the binder phase itself, and further improving the wettability with the dispersed phase. However, if the content is less than 1%, the desired effect of improving the above effect cannot be obtained;
If the content exceeds 1%, the strength not only decreases, but also a brittle intermetallic compound is formed and toughness is lost. Therefore, the content was set at 1 to 20%. The reason why the TaN content in the cutting edge layer of the composite ultra-high pressure sintered piece of this invention is set at 10 to 20% is because if the content is less than 10%, the desired toughness cannot be obtained. This is because when its content exceeds 20%, wear resistance decreases.

[Table] It is a thing. Next, the composite ultra-high pressure sintered piece of the present invention will be specifically explained using examples. As raw material powders, CBN powder, TaN powder, and TiN all have an average particle size within the range of 0.5 to 1.5 μm.
Powder, ZrN powder, VN powder, HfN powder, (Ti _0.85
Nb _0.15 ) N powder, (Ti _0.9 Zr _0.1 ) N powder, (Ti _0.9
V _0.1 ) N powder, WC powder, Cr powder, Mo powder, W
Powder, Fe powder, Co powder, and Ni powder are prepared, and these raw material powders are each blended into the composition shown in Table 1, and after mixing, they are placed in a cylindrical thin-walled container made of Zr to form a retaining layer. Charge 200mg of uniformly mixed powder for forming a cutting edge layer, then charge and fill 60mg of uniformly mixed powder for forming a cutting edge layer, and then heat the entire container filled with the mixed powder under normal ultra-high pressure. After being charged into a high temperature generator and sintered under ultra-high pressure under the conditions of holding the pressure and temperature shown in Table 1 for 30 minutes each, it was slowly cooled to a temperature of 1300℃, and then rapidly cooled. , finally, by performing normal post-processing, it has substantially the same component composition as the blended composition, and the shape shown in the schematic perspective view in FIG. 1, that is, the planar shape: central angle 90 Composite ultra-high pressure sintered piece 1 of the present invention having a fan shape with a radius of 3.0 mm in degrees, a thickness of the cutting edge layer 1a: 0.5 mm, and a thickness of the retaining layer 1b: 2.0 mm (total thickness: 2.5 mm). -6 were produced. The resulting composite ultra-high pressure sintered piece 1 of the present invention
- 6 were polished with a diamond wheel and the structure was observed, and it was found that the upper cutting edge layer 1a
and the lower retention layer 1b both have a theoretical density ratio of 100%.
It showed a fine uniform structure. Further, the fracture surface exhibited an irregular fracture surface, and no pores were observed in the interior as well as at the interface between the two layers, and it was confirmed that the two layers were firmly adhered to each other. Further, the above-mentioned retaining layer had a Vickers hardness shown in Table 2. On the other hand, for comparison purposes, the retention layer was WC-6% by weight.
The manufacturing conditions are the same as the above-mentioned composite ultra-high pressure sintered piece of the present invention, except that the WC-based cemented carbide having a composition of Co is used and the ultra-high pressure sintering conditions are as shown in Table 1.

Conventional composite ultra-high pressure sintered pieces 1 and 2 were manufactured under the conditions shown in [Table]. Conventional composite ultra-high pressure sintered piece 1 obtained as a result,
In No. 2, pores were observed. Table 2 also shows the Vickers hardness of the retention layer. Next, these composite ultra-high pressure sintered pieces were assembled into a WC-based carbide film with a planar dimension of 12.7 mm□ and a thickness of 4.8 mm, as shown in a plan view in Fig. 2 and a front view in Fig. 3. Alloy cutting tip (throwaway tip) 2
Attach it to the cutting edge of one of the four corners by brazing, and then attach it to the cutting tool, and then workpiece material: Inconel 718, cutting speed: 120 m/min, feed: 0.15 mm/rev., depth of cut: 1.0 mm, side edge angle:
A cutting test was conducted under the conditions of 45°, cutting oil: water-soluble cutting oil, and the cutting time until the flank wear width reached 0.3 mm was measured. The measurement results are shown in Table 2. Table 2 also shows the state of the cutting edge. As shown in Table 2, all of the composite ultra-high pressure sintered pieces 1 to 6 of the present invention show normal wear, so it is easy to understand that the bonding strength between the cutting edge layer and the retaining layer is extremely high. Furthermore, it is clear that the cutting life is much better than that of the conventional composite ultra-high pressure sintered pieces 1 and 2. In addition, in the above example, the composite ultra-high pressure sintered piece was
Although we have described the case where it is used by attaching it to the cutting edge of a cutting tip made of WC-based cemented carbide, it goes without saying that the composite ultra-high pressure sintered piece may be made larger and used as a cutting tip as it is. It is. As mentioned above, the composite ultra-high pressure sintered piece of the present invention has excellent toughness and wear resistance by configuring the retaining layer with the TiN-based ultra-high pressure sintered material having the above-mentioned composition. In addition, the bonding strength between the cutting edge layer and the retaining layer is extremely high, so it has industrially useful properties such as being able to further extend the cutting life, especially when cutting difficult-to-cut materials. It is something that you have.

[Brief explanation of drawings]

FIG. 1 is a schematic perspective view showing an embodiment of the composite ultra-high pressure sintered piece, FIG. 2 is a plan view showing the composite ultra-high pressure sintered piece attached to the cutting edge of a cutting tip, and FIG.
The figure is a front view of the same. In the drawings, 1, 1'... Composite ultra-high pressure sintered piece, 1a... Cutting edge layer, 1b... Holding layer, 2... Cutting chip.

Claims (1)

[Scope of Claims] 1. A cutting edge layer of a cubic boron nitride-based ultra-high pressure sintered material containing 10 to 20% of tantalum nitride, with the remainder consisting of cubic boron nitride and unavoidable impurities; Titanium: 50-95%; One or more of the nitrides of V, Ta, Nb, Zr, and Hf: 1-20%; One or more of the nitrides of Cr, Mo, and W. : 1 to 20%, with the remainder being one of Fe, Co, and Ni
Composite ultra-high-pressure sintered material for cutting blades, characterized in that it is composed of a laminated composite of a holding layer of a titanium nitride-based ultra-high-pressure sintered material having a composition (by weight %) of a species or two or more species and unavoidable impurities. piece.