JPS629551B2 - - Google Patents

Description

[Detailed description of the invention]

This invention has both high hardness and high toughness, as well as excellent wear resistance and welding resistance, and is particularly suitable for cutting Ni-based or Co-based super alloys and high-speed steel, which require these characteristics. The present invention relates to a cubic boron nitride-based ultra-high pressure sintered material that is suitable for use as tools and wear-resistant tools such as bearings and wire drawing dies. In recent years, compared to tungsten carbide-based cemented carbide,
Attempts have been made to use cubic boron nitride-based ultra-high pressure sintered materials (hereinafter abbreviated as CBN-based sintered materials), which have extremely excellent wear resistance, as cutting tools and wear-resistant tools. These existing CBN-based sintered materials can be roughly divided into two types depending on the binder phase of the CBN particles that form the dispersed phase. A metal whose main component is 〓〓〓〓〓
The other type is made of ceramic whose main component is titanium nitride, titanium carbide, aluminum nitride, or aluminum oxide. However, if the binder phase of the former is composed of metal
Although CBN-based sintered materials have high toughness, they tend to soften at high temperatures. Therefore, when used as cutting tools, for example, they have high wear resistance and anti-welding properties under harsh cutting conditions that generate a large amount of heat. It cannot be used because it causes a lack of performance, and it can only be used under conditions of low load (low heat generation). In addition, the latter ceramic is used as the bonding phase.
CBN-based sintered materials have excellent wear resistance and welding resistance, but have the problem of poor toughness. Therefore, from the above-mentioned viewpoint, the present inventors conducted research to obtain a CBN-based sintered material with high toughness and excellent wear resistance and welding resistance. The sintered material is composed of carbides, nitrides, and carbonitrides of metals from Groups 4a and 5a of the periodic table, carbides of metals from group 6a of the periodic table, and solid solutions of two or more of these metals, by weight%. One or more types of (hereinafter collectively referred to as metal carbon/nitride): 10 to 70%, Al carbide (hereinafter referred to as Al ₄ C ₃ ) and carbonitride (hereinafter referred to as AlCN) ) one or two of the following
Species: 1 to 40%, and if necessary, one or more of Ni, Co, and Fe (hereinafter referred to as iron group metals): 1 to 10%, and the remainder When composed of CBN (containing 30 to 90% by volume) and unavoidable impurities,
In the resulting CBN-based sintered material, high hardness, that is, excellent wear resistance and excellent welding resistance are ensured by the carbon/nitride of the above metal and CBN, and the above Al ₄ C ₃ and CBN They found that AlCN ensures high toughness. This invention was made based on the above knowledge, and the reason why the component composition range was limited as described above will be explained below. (a) Metallic carbon/nitride These components have the effect of forming a dispersed phase and imparting excellent wear resistance and welding resistance to the material, but if their content is less than 10%, the above effects will be reduced. However, if the content exceeds 70%, the toughness of the material decreases, so the content was set at 10 to 70%. (b) Al ₄ C ₃ and AlCN These components have the effect of further improving the toughness of the material without impairing the wear resistance and welding resistance, but if their content is less than 1%, this effect will not be achieved. On the other hand, if the desired effect is not obtained, and if the content exceeds 40%, CBN particles tend to grow, and not only the wear resistance deteriorates, but also the toughness tends to decrease. Therefore, the content was set at 1 to 40%. (c) Iron group metals These components include CBN particles forming the dispersed phase, metal carbon/nitride particles, and AlN, AlCN.
These properties are required because it works by penetrating between particles and further improving sinterability during material manufacturing, and forming a binder phase in the material to further improve the toughness of the material. It is included as necessary when the content is 1
If the content is less than 10%, the desired effect of improving the above action will not be seen, while if the content exceeds 10%, the wear resistance and welding resistance of the material will deteriorate. %. (d) CBN Since this component has extremely high hardness and excellent heat resistance, the inclusion of this component gives the material extremely excellent wear and welding resistance. If the amount is less than 30% by volume, the desired characteristics cannot be secured,
On the other hand, if the content exceeds 90% by volume, the contact ratio between CBN particles becomes too high, which not only causes the material to become brittle, but also deteriorates sinterability, leaving fine pores in the material. The content of
It was set at 30-90% by capacity. The CBN content expressed in volume % is, for example, when comparing the specific gravity of WC and CBN, WC: 15.8 g/cm ³ and CBN:
3.48 g/cm ³ , and the difference between the two is significant. Therefore, even if the content is small in terms of weight, the volume ratio that actually affects the properties is quite large. Furthermore, the CBN-based sintered material of the present invention can be used, for example, as follows.
When used as a cutting tool, it can be used as a throw-away tip either alone or in combination with a high-rigidity material such as tungsten carbide-based cemented carbide or titanium carbide-based cermet.
Furthermore, these chips can be used while being attached by brazing to the tip of a holder made of tungsten carbide-based cemented carbide, hardened steel, or the like. Next, the CBN-based sintered material of the present invention will be specifically explained using Examples. Example: As raw material powder, average particle size: 2 μm
CBN powder, all with an average particle size of 1 μm
TiC powder, ZrC powder, HfC powder, VC powder, NbC powder, TaC powder, _Cr3C2 powder, _Mo2C powder, WC powder, TiN powder, ZrN powder, HfN powder, _VN powder,
NbN powder, TaN powder, TiCN powder, ZrCN powder,
VCN powder, TaCN powder, (Ti, W)C powder, (Zr,
Ta) C powder, (Ti, Zr) C powder, (Ti, Ta, W)
C powder, (Ti, Zr) N powder, (Nb, Ta) N powder,
(Ti, W) CN powder, (Ti, Zr) CN powder, (Zr,
Mo, W) CN powder, ((Ti, Ta, W) CN powder,
Al ₄ C ₃ powder, AlCN powder, both 0.5 μm Co
Powder, Ni powder, and Fe powder were prepared, and these raw material powders were blended into the composition shown in Table 1, mixed in a ball mill under normal conditions, and then milled with a pressure of 2 tons/cm ² in diameter: 15 mmφ. ×Thickness: 2mm
These compacts were then inserted into a container of a known ultra-high pressure and high temperature generator at a pressure of 55 kb, a temperature of 1200°C, and a holding time of 1. Invention CBN-based sintered materials 1 to 34 and comparative CBN having substantially the same composition as the blended composition by ultra-high pressure sintering under conditions of
Base sintered materials 1 to 8 were each manufactured. Comparative CBN-based sintered materials 1 to 8 all have compositions in which the content of one of the constituent components (marked with * in Table 1) is outside the scope of this invention. It is. Next, for the resulting CBN-based sintered materials 1 to 34 of the present invention and comparative CBN-based sintered materials 1 to 8, the Vickers hardness was measured. Determine the fracture toughness value Kc based on the length of the crack that occurred from the tip of the indentation, and then calculate the wear resistance and welding resistance.

[Table] 〓〓〓〓〓

[Table] 〓〓〓〓〓

[Table] For the purpose of evaluating, work material: die steel SKD11
(Hardness: Rockwell hardness C scale 62), Depth of cut: 0.2mm, Feed: 0.1mm/rev., Cutting speed: 100
A cutting test was conducted at m/min without cutting oil, and the cutting time until the flank wear of the cutting edge reached 0.2 mm was measured. These results are also shown in Table 1. From the results shown in Table 1, the CBN-based sintered materials 1 to 34 of the present invention all have high hardness and excellent toughness, and therefore have excellent cutting performance even in difficult-to-cut materials such as die steel. On the other hand, as seen in Comparative CBN-based sintered materials 1 to 8, if the content of any of the constituent components falls outside the range of this invention, the toughness becomes inferior, It is clear that good cutting performance cannot be obtained when used as a cutting tool. As mentioned above, the CBN-based ultra-high pressure sintered material of this invention has excellent toughness, wear resistance, and welding resistance, so it is suitable for cutting difficult-to-cut materials that require these properties. Not only when used as a cutting tool, but also when used as a wear-resistant tool such as a bearing or wire drawing die, it exhibits excellent performance over a long period of time. 〓〓〓〓〓

Claims (1)

[Claims] 1% by weight of a group consisting of carbides, nitrides, and carbonitrides of metals from groups 4a and 5a of the periodic table, carbides of metals from group 6a of the periodic table, and solid solutions of two or more of these metals. One or more of the following: 10-70
%, one or two of Al carbides and carbonitrides: 1 to 40%, and the remainder is cubic boron nitride (however, 30 to 90%).
A cubic boron nitride-based ultra-high pressure sintered material for cutting tools and wear-resistant tools, characterized by having a composition consisting of (% by volume) and unavoidable impurities. 2% by weight of carbides, nitrides, and carbonitrides of metals from groups 4a and 5a of the periodic table, carbides of metals from group 6a, and solid solutions of two or more of these metals; or 2 or more types: 10-70
%, one or two of Al carbides and carbonitrides: 1 to 40%, one or more of Ni, Co, and Fe: 1 to 10%, and the rest is Cubic boron nitride (30 to 90
A cubic boron nitride-based ultra-high pressure sintered material for cutting tools and wear-resistant tools, characterized by having a composition consisting of (% by volume) and unavoidable impurities.