JPS602376B2 - Sintered material for cutting tools with excellent high-temperature properties - Google Patents

Description

[Detailed Description of the Invention] The present invention provides a scale material that has excellent high-temperature properties and exhibits excellent performance when used as a cutting tool particularly in high-speed cutting and high-feed cutting that require these properties. It is related to.

Generally, when cutting steel, when the cutting speed is increased or the feed rate is increased, the temperature of the cutting tool's cutting edge increases, and the cutting tool reaches the end of its useful life due to plastic deformation caused by the high temperature rather than wear. In many cases, this preference is becoming stronger due to the recent advances in high-speed cutting and high-efficiency cutting.

However, in the cemented carbides and cermets currently in practical use whose dispersed phase is mainly composed of W carbide or Ti carbide, while the binder phase is mainly composed of iron group metals, when the cutting edge temperature exceeds 1000 °C, Because they soften rapidly, not only these cemented carbide and cermets, but also surface-coated cemented carbide and surface-coated cermets with a hard coating layer formed on their surfaces must be used at a cutting edge temperature of 1000 qo. It is limited to slightly more than that. On the other hand, ceramics containing AI oxide as a main component exhibit high hardness and excellent oxidation resistance at high temperatures, and are therefore used in practical applications as high-speed cutting tools.However, even with this ceramic, the cutting edge lacks high-temperature stability. However, due to insufficient reliability, the current situation is that low feed rates are used during high-speed cutting. In addition, in recent years, cast alloys having a structure in which carbides of W and Ti are dispersed in layers in a matrix of high-melting point metals such as W or Mo have been proposed as cutting tool materials for high-speed cutting and high-feed cutting. (See, for example, US Pat. No. 3,690,962),
However, this cast alloy has a significantly high melting point of 2,700°C, is difficult to shape because it is a cast alloy, and has insufficient oxidation resistance and impact resistance, so it is not widely put into practical use. It was something that could not be reached.

Therefore, from the above-mentioned viewpoint, the present inventors have developed a technology that enables high-speed cutting and high-feed cutting, and has excellent wear resistance, plastic deformation resistance, oxidation resistance, and impact resistance, that is, excellent high-temperature properties. As a result of research, it was found that scale materials with Ti: 10-35%, Zr and H
One or two of f: 5-30%, Nb and T
One or two of a: 5-30%, C: 20-4
0%, Re: 5-20%, and the remainder is W and unavoidable impurities (however, W: 20-60%). When the components are completely dissolved at a high temperature and the temperature is increased rapidly from the condensation temperature, the dispersed phase consists of a compound phase mainly composed of Ti and C, one or two of Zr and m, and C. The resulting material consists of a fine hard phase with a compound phase mainly composed of W and Re, while the binder phase has a structure consisting of a high melting point alloy phase mainly composed of W and Re. In addition to significantly improving impact resistance due to the high melting point alloy phase mainly composed of W and Re as the binder phase, it also has excellent plastic deformation resistance and oxidation resistance, and is composed of the fine hard phase. Coupled with the excellent wear resistance of the dispersed phase,
They have come to the knowledge that when used as a cutting tool for high-speed cutting or high-feed cutting, it exhibits extremely excellent cutting performance.

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-Ti Ti forms a compound phase mainly composed of Ti and C, giving the material high hardness and thereby improving wear resistance, but if its content is less than 10 at%, During the cooling process from the solid solution state in the aging process, the desired amount of fine compound phase mainly composed of Ti and C cannot be precipitated, resulting in low wear resistance. If the content exceeds 10%, the amount of dispersed phase becomes too large relative to the binder phase, resulting in deterioration of impact resistance. Therefore, the content was set at 10 to 35 at%.

'b} Zr and Hf These components also have the effect of precipitating a compound phase containing one or two of Zr and Hf and C as main components to improve wear resistance, but their content The amount is 5 atomic%
If the content is less than 30 atomic %, the desired high hardness and high wear resistance cannot be achieved like with Ti, while if the content exceeds 30 atomic %, the dispersed phase becomes too large and the impact resistance deteriorates. The content is 5 to 30%.
Defined as atomic percent.

'c) Nb and Ta These components have the effect of improving oxidation resistance by diffusing into the compound phase whose main components are Ti, Nb, m, and C, respectively, but their content is 5 at%. If the content is less than 30 atomic %, the desired effect cannot be obtained, whereas if the content exceeds 30 atomic %, the wear resistance decreases. Therefore, the content was set at 5 to 30 atomic %.

{d} C The C component combines with Ti, Zr, Hf, Nb, Ta, and W in some cases to form a dispersed phase consisting of a fine hard phase, improving the wear resistance of the material. However, if the content is less than 20 at%, the amount of the dispersed phase is relatively too small to ensure the desired wear resistance, while if the content exceeds 40 at%, If the amount of dispersed phase relative to the binder phase becomes too large, the impact resistance of the material will deteriorate, so the content should be reduced to 20-40%.
Defined as atomic percent.

[e'Re The Re component has the effect of forming a melting point alloy phase as a binder phase with W, and significantly improving the plastic deformation resistance, oxidation resistance, and impact resistance of the material, but its content is is less than 5 at%, the desired effect cannot be obtained;
If the content exceeds atomic %, the binder phase becomes too large and the wear resistance of the material deteriorates.
Its content was determined to be 5 to 20 at%.

'f' The VVW component mainly combines with Ti and C to form a dispersed phase, and the remaining main part forms a high melting point alloy phase as a binder phase with Re, improving the plastic deformation resistance of the material. , has the effect of improving oxidation resistance and impact resistance, but if its content is less than 20 at %, the binder phase will be relatively small and the ratio to Re will also be low, so that the desired effect will not be achieved. On the other hand, if 60 atomic % is contained, the wear resistance and oxidation resistance will deteriorate, so the content was set at 20 to 60 atomic %.

Note that the Tsukatai material of the present invention contains one or more of oxygen, nitrogen, Fe, Co, Ni, Cr, Mo, AI, etc. as inevitable impurities, but the total content is 5 atomic % or less. If present, the properties of this coagulated material will not be impaired in any way.

Next, the material of the present invention will be specifically explained with reference to Examples.

Example 1 Titanium carbide powder having an average particle size of 1.0 mm, zirconium carbide powder with an average particle size of 1.5 mm, and 1.5 mm particle diameter were used as raw material powders.
Prepare hafnium carbide powder of 5 mounds, tantalum carbide powder of 1.0 m2, W powder of 0.8 m2, and Re powder of 1.0 m2, and prepare these raw powders as shown in Table 1. The composition shown is mixed, wet-mixed in a ball mill for 7 hours, dried, and then press-molded at a pressure of 15k9/m2 to form a compacted powder.
After freezing at a temperature of 2100°C for 1 hour in a vacuum of Sintered materials 1 to 5 of the present invention and Hisame baked striped materials 1 to 6 having the same final component composition were produced, respectively.

Table 1 Comparative Dawn Supply Materials 1 to 6 all have a composition in which one of the components (indicated by * in Table 1) is outside the scope of the present invention.

Next, a cutting tip having a shape of SNP432 was prepared from the resultant fastening materials 1 to 5 of the present invention and comparative fastening materials 1 to 6, and the cutting tip was prepared using the following materials: JIS/SNCM-8 (
Hardness: HB250), Cutting speed: 250'min, Feed: 0.3 ribs/rev, Depth of cut: 2 ribs, Cutting time: 10
Continuous cutting test under conditions of 10 minutes, and work material: JIS/S
NCM-8 (Hardness: HB280), Cutting speed: 140min, Feed: 0.3mm, Depth of cut: 2mm, Cutting time:
An interrupted cutting test was conducted under conditions of 3 minutes, and in the above continuous cutting test, the flank wear depth and crater wear depth on the chip cutting edge were measured, and in the above interrupted cutting test,
The number of broken cutting edges among the 10 tested cutting edges was measured.

These measurement results are also shown in Table 1. In addition, the first
For comparison purposes, the table includes a commercially available ceramic cutting tip mainly composed of aluminum oxide (hereinafter referred to as conventional cutting tip 1), and a tungsten carbide-based cemented carbide substrate with titanium carbide and oxide. The results of a cutting test under the same conditions for a surface-coated cemented carbide cutting tip (hereinafter referred to as conventional cutting tip 2), which is coated with a hard layer consisting of two layers of aluminum, are also shown. As shown in Table 1, the cutting chips manufactured using the inventive cohesive materials 1 to 5 were tested in the lotus mirror and interrupted cutting tests, as well as the cutting chips made from the comparative cohesive materials 1 to 6 and the conventional cutting chips 1, 2, and 3. 2
It is clear that the cutting performance is much better than that of the previous one.

Example 2 As raw material powders, in addition to the same raw material powders used in Example 1, niobium carbide powder having an average particle size of 1.2 mounds was prepared, and these raw material powders were blended as shown in Table 2. The Akatsuki Materials 6 to 9 of the present invention and the Bisame Yakistriped Materials 7 to 1 were prepared under the same conditions as in Example 1 except that they were added to the composition.
2 were produced respectively.

Next, cutting tips each having a shape of SNP432 were prepared from the resulting brined materials 6 to 9 of the present invention and comparative lamp materials 7 to 12, and the work material was JIS/SN.
CM-8 (hardness: HB250), cutting speed: 100/
Continuous cutting test under the conditions of min, feed: 0.7 ribs'rev, depth of cut: 8 ribs, cutting time: 1 minute, and work material: SN.
CM-8 (hardness: HB280), cutting speed: 100'
An intermittent cutting test was conducted under the following conditions: min, feed: 0.4 side'rev, depth of cut: 3 ribs, cutting time: 3 minutes, Example 1
Similarly, in the above continuous cutting test, flank wear depth and crater wear depth were measured, and in the above interrupted cutting test, l
The number of defects among the q-hard cutting edges was measured.

The measurement results are also shown in Table 2. Table 2 Also, for comparison purposes, Table 2 shows surface-coated cemented carbide cutting tips (all of which are made of a commercially available tungsten carbide-based cemented carbide substrate coated with a hard layer of titanium carbide). The cutting test results under the same conditions for a P30 tungsten carbide-based cemented carbide cutting tip (hereinafter referred to as conventional cutting tip 4) are also shown.

Claims (1)

[Claims] 1 Ti: 10-35%, one or two of Zr and Hf: 5-30%, one or two of Nb and Ta: 5-30%, C: 20-40%, Re :5
~20%, and the rest is W and unavoidable impurities (however, W:
20 to 60%), and the dispersed phase is a compound phase containing Ti and C as main components, one or two of Zr and Hf, and C. A cutting tool with excellent high-temperature properties characterized by having a structure consisting of a fine hard phase with a compound phase mainly composed of sintered material.