JPH0123241B2 - - Google Patents

Description

[Detailed description of the invention]

This invention relates to a composite cutting chip that has excellent wear resistance and has high mutual bonding strength of the composite material brazed to the cutting edge, and therefore exhibits stable cutting performance over a long period of time. . Conventionally, the dispersed phase was generally composed of cubic boron nitride (hereinafter referred to as CBN), while the binder phase was composed of TiC,
An upper layer of a CBN-based sintered material made of one or more of TiCN, WC, AlN, etc. and/or an iron group metal, and a dispersion layer.
Composed of WC, while the bonded phase was composed of Co
A composite consisting of a lower layer of WC-based cemented carbide,
Composite cutting tips made of WC-based cemented carbide, high-speed steel, etc., and brazed to the cutting edge are in practical use. However, in the above-mentioned conventional composite cutting tip, the above-mentioned composite is heated at high temperature and high pressure, e.g.
Since it is manufactured by sintering at 1400℃ and pressure: 55Kb, Co, which constitutes the binder phase in the lower layer, diffuses into the upper layer during sintering.
Not only does the wear resistance of the upper layer deteriorate due to this Co diffusion, but the composite cutting chip itself is expensive, so it is re-ground and reused after its useful life. , since the amount of Co diffusion is not constant, there is a large variation in cutting life.
There were problems such as significant inconvenience in its management. Therefore, from the above-mentioned viewpoint, the present inventors have developed a composite cutting chip that does not impair the excellent wear resistance of the CBN-based sintered material that constitutes the lower layer of the composite in the composite cutting chip. As a result of conducting research to develop a material with properties suitable for the lower layer of the composite, we replaced the lower layer of the composite in the conventional composite cutting tip with WC-based cemented carbide by weight%. 4a of the periodic table as a hard dispersed phase forming component,
5a and 6a group metals, as well as carbides, nitrides, oxides, and borides of Mg, Ca, Al, and Si, and one of solid solutions of two or more of these.
Species or two or more species: 10 to 70%, W or W-Mo alloy as a binder phase forming component, and unavoidable impurities: the remainder:
In this cermet, there is no diffusion of binder phase-forming components into the upper layer made of CBN-based sintered material during sintering, so the excellent wear resistance of the upper layer is not impaired, and moreover, the upper layer is The resulting composite cutting chip has high bonding strength and superior rigidity and heat resistance compared to WC-based cemented carbide, resulting in excellent cutting performance that is stable over an extremely long period of time. We have obtained the knowledge that it will become more effective. Therefore, the present invention has been made based on the above knowledge, and provides a composite cutting chip in which a composite of an upper layer of CBN-based sintered material and a lower layer of cermet is brazed to the cutting edge. 4a of the periodic table as a hard dispersed phase forming component,
5a and 6a group metals, as well as carbides, nitrides, oxides, and borides of Mg, Ca, Al, and Si, and one of solid solutions of two or more of these.
The present invention is characterized in that it is made of a cermet having a composition consisting of a species or two or more species: 10 to 70%, W or W--Mo alloy as a binder phase forming component, and the remainder: unavoidable impurities. In addition, in the lower layer part of the composite of the composite cutting tip of this invention, the content of the hard dispersed phase forming component is
The reason for limiting the content to 10 to 70% is that if the content is less than 10%, the content of the binder phase forming component will be relatively too high, exceeding 90%, and it will not be possible to secure the desired wear resistance. On the other hand, if the content exceeds 70%, the content of the binder phase forming component will be relatively less than 30%, resulting in a significant lack of toughness. It was established. Next, the composite cutting chip of the present invention will be specifically explained using examples. Example: CBN powder with an average particle size of 5 μm and 1 μm as raw material powder for forming the upper layer in a composite
TiN powder of 1.5 μm, Ti _0.5 N _0.5 powder of 2 μm
AlN powder, 2.2 μm WC powder, and 1.2 μm Co powder were prepared, and as raw material powders for forming the lower layer, W powder with an average particle size of 0.8 μm, and (Ti _0.6 WJ _0.4 ) with an average particle size of 1.5 μm. C _0.7 N _0.3 powder, 1.2 μm TiN powder,
Al ₂ O ₃ powder of 0.5 μm, MgO powder of 0.4 μm,
2.0μm ZrC powder, 1.5μm TaC powder, 1.8μm
NbC powder with a diameter of 0.4 μm and CaO powder with a diameter of 0.4 μm were prepared, and these raw material powders were blended into the composition shown in Table 1. After mixing both in a ball mill for 72 hours, the upper layer part had a diameter of :8mm
It was press-formed into a green compact with dimensions of φ x thickness: 1.5 mm, and the lower layer was formed at a predetermined pressure and sintered under the same conditions shown in Table 1. After that, it was polished to dimensions of outer diameter: 8 mmφ x thickness: 3 mm, and then the upper layer partial compact and the lower layer partial sintered compact formed in this way were stacked and charged into a stainless steel container. Pressure this container:
After maintaining the temperature at 1100℃ for 30 minutes in a vacuum of 10 ^-4 mmHg to fully degas the inside, it was charged into a girdle-type ultra-high pressure and high temperature device, using pyroferrite as the pressure medium, and A graphite cylinder was used as the heating element, and the composite was sintered under the conditions of pressure: 55 Kb, temperature: 1400°C, and holding time: 30 minutes. Composite cutting tips 1 to 1 of the present invention are produced by brazing the composite to the cutting edge of a WC-based cemented carbide cutting tip having a shape conforming to ISO standard SNGN432.
8 and conventional composite cutting chips 1 and 2 were manufactured. Next, regarding the composite cutting chips 1 to 8 of the present invention and the conventional composite cutting chips 1 to 2 obtained as a result, Work material: Hardened steel round bar (Material: SKD-11, Hardness: H _R C60), Cutting Speed: 70m/mm, feed: 0.1mm/rev., depth of cut: 0.2mm, cutting time: 15mm,

[Table] Cutting: Continuous cutting test under the conditions of , Work material: Hardened steel square material (Material: SKD-11, Hardness: H _R C50), Cutting speed: 120 m/mm, Feed: A milling test was conducted under the following conditions: 0.3mm/blade, depth of cut: 0.7mm, cutting time: 15mm, cutting fluid: not used, and in the above continuous cutting test, the flank wear width and rake face wear depth of the cutting edge were measured. In addition, in the milling cutting test, the cutting time until chipping occurred on the cutting edge was measured. The results of these measurements are shown in Table 1. From the results shown in Table 1, composite cutting chips 1 to 8 of the present invention all have excellent wear resistance in continuous cutting tests, and no chipping is observed in milling tests. Therefore, the conventional composite cutting chips 1 and 2 had relatively low wear resistance, and chipping and peeling of the composite were observed, and it is clear that the cutting properties were inferior to the composite cutting chips of the present invention. be. As mentioned above, in the composite cutting tip of the present invention, the bonding strength of the lower layer to the upper layer of the composite is extremely high, and the lower layer has excellent rigidity and heat resistance, so that it is easy to cut when cutting. In addition to exhibiting excellent wear resistance, the cutting edge exhibits no chipping or peeling, and exhibits excellent cutting performance over a long period of time.

Claims (1)

[Claims] 1. An upper layer portion of a cubic boron nitride-based sintered material;
In a composite cutting chip formed by brazing a composite with a lower layer portion of cermet to the cutting edge portion, the lower layer portion is classified as 4a of the periodic table as a hard dispersed phase forming component in weight%.
5a and 6a group metals, as well as carbides, nitrides, oxides, and borides of Mg, Ca, Al, and Si, and one of solid solutions of two or more of these.
1. A composite cutting chip characterized in that it is made of a cermet having a composition of: 10 to 70% of a species or two or more species, W or W-Mo alloy as a binder phase forming component, and the remainder of unavoidable impurities.