JPS6022057B2 - Sintered material for cutting tools with excellent high-temperature properties and its manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a bonding material that has excellent high temperature properties and exhibits excellent cutting performance when used as a cutting tool for high-speed cutting or high-feed cutting that particularly requires high-temperature properties. and its manufacturing method.

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 trend is becoming stronger due to recent advances in high-speed cutting and high-efficiency cutting.

However, the cutting edge temperatures of cemented carbides and cermets currently in practical use, where the dispersed phase is mainly composed of W carbide or Ti carbide and the binder phase is mainly composed of iron group metals, have a cutting edge temperature of over 1000°C. Because of this, not only these cemented carbides and cermets, but also surface-coated cemented carbide and surface-coated cermets with a hard coating phase formed on their surfaces, must be used under certain conditions at the cutting edge. The temperature is limited to slightly above 1000 qo. On the other hand, ceramics whose main component is N oxide exhibit high hardness and excellent oxidation resistance at high temperatures, so they are used as cutting tools for high-speed cutting, but their cutting edges are not impact resistant. Because of this lack of reliability and insufficient reliability, it is currently used at low feed rates for high-speed cutting. In addition, in recent years, cast alloys (for example, US (See Patent No. 3690962 specification) was proposed,
However, this cast alloy has a significantly high melting point of 2,700°C, and since it is a cast alloy, it is difficult to give it a shape, and it also has insufficient oxidation resistance and impact resistance. It has not yet been widely put into practical use.

Therefore, from the above-mentioned viewpoint, the present inventors have developed a material for cutting tools that has excellent high-temperature properties that enable high-speed cutting and high-feed cutting, that is, wear resistance, plastic deformation resistance, oxidation resistance, and As a result of research to manufacture cutting tools with excellent impact resistance and bending using powder metallurgy, we found that as a raw material powder,
metal carbide powder, metal shelving powder, metal carbon shelving powder,
and W powder are prepared, two or more of these raw material powders are blended into a predetermined composition, mixed under normal conditions, press-molded, and the resulting green compact is made into a non-oxidizing powder. In an atmosphere, it is sintered at a temperature of 2,000 to 2,700°C, that is, the complete solid solution temperature, and then cooled from this sintering temperature and subjected to a compound precipitation treatment at a temperature of 1,000 to 160,000. 25%, Zr and Hf
One or two of these: 5-20%, One or two of Nb and Ta: 5-20%, C: 15-40%
, B: 1 to 10%, the rest being W and inevitable impurities (
However, the dispersion layer has a composition consisting of a compound phase mainly composed of Ti, C, and B, one or two of Zr and Hf, and C. When a scale alloy is produced which has a structure consisting of a fine hard phase with a compound phase mainly composed of B and a W-based alloy whose binder phase is mainly composed of W, the resulting anti-binding material is It has excellent wear resistance, plastic deformation resistance, oxidation resistance, and impact resistance, and is therefore extremely effective when used as a cutting tool for high-speed cutting and high-feed cutting that require these high-temperature properties. They obtained the knowledge that it exhibits excellent cutting performance.

This invention has been made based on the above findings, and the reason why the composition range of the material and the brining temperature are limited as described above will be explained below. 'a- TiTi component forms a compound phase mainly composed of Ti, C, and 8, which is dispersed as a fine hard phase in the base material, imparting high hardness to the material, thereby improving the wear resistance of the material. However, if the content is less than 5%, the desired amount of the compound cannot be precipitated in the compound precipitation treatment step, and as a result, the desired wear resistance cannot be ensured.
On the other hand, if the content exceeds 25%, the amount of the compound forming the dispersed phase becomes too large compared to the binder phase, and the impact resistance of the material deteriorates. It was set at 25%.

{b- Zr and Hf Both components are Zr as well as Ti.
The main components are one or two of Hf and C and B, and have the effect of improving the wear resistance of the material by forming a compound phase that is dispersed as a fine hard phase in the matrix. If the content is less than 5%, high hardness, that is, high wear resistance, similar to Ti, cannot be ensured, while if the content exceeds 20%, the compound phase that forms the dispersed phase increases as well. If too much, the impact resistance of the material deteriorates, so the content was set at 5 to 20%.

'c} Nb and Ta These two components have the effect of improving the oxidation resistance of the material that is diffused into the above two compound phases and dissolved in the base material, but if their content is less than 5% However, if the content exceeds 20%, the wear resistance of the material tends to deteriorate, so the content was set at 5 to 20%.

(d) C The C component forms two types of compound phases as described above and has the effect of improving the wear resistance of the material, but if its content is less than 15%, the amount of the hard dispersed phase is relatively low. If the content is too small, it is not possible to secure the desired wear resistance, while if the content exceeds 40%, the ratio of the compound phase to the binder phase becomes too large, leading to deterioration of the impact resistance of the material. Therefore, the content was determined to be 15 to 40%.

{e} B As mentioned above, the B component has the effect of hardening the hard compound phase uniformly dispersed in the base material and improving the wear resistance of the material, so if its content is less than 1%, The desired wear resistance cannot be obtained, and if the content exceeds 10%, the impact resistance of the material deteriorates, so the content was set at 1 to 10%.

'f] W A part of the W component diffuses into the above compound phase, but
Most of the remainder constitutes the binder phase of the base material, and this binder phase consists of a W-based alloy in which the components constituting the dispersed phase described above are dissolved, so the material has excellent plastic deformation resistance and impact resistance. It becomes valuable.

However, if the content is less than 20%, the amount of the binder phase is relatively too small, resulting in particularly poor impact resistance, while if the content exceeds 55%, the amount of the dispersed phase is relatively small. If the amount is too low, the wear resistance of the material will deteriorate, so the content is set at 20 to 55%. Note that the resulting binder contains unavoidable impurities such as Fe, Ni,
Co, Cr, Mo, Si, N and platinum group metals (Pt,
Even if it contains one or more of Pd, Rh, R mountain lr, melon), as long as the total content is 2% or less, the properties of this sintered material will not be impaired in any way. do not have.

'g- Dawning temperature At competitive temperatures below 200 and 0, the structure at dawn does not become a complete collective solution, and as a result, in the compound precipitation process after dawning,
It is not possible to obtain a maple fabric in which a fine hard compound phase is uniformly dispersed in a W-based alloy base, and as a result, it is not possible to secure the desired wear resistance and impact resistance.
If the dawning temperature exceeds 700 qo, a liquid phase will appear and it will be difficult to maintain the shape, so the dawning temperature was set at 2000 to 2700°C.

'h} Compound Precipitation Processing Temperature If the temperature is less than 100,000, too few compounds will be separated out, making it impossible to obtain a structure in which fine hard compounds are uniformly dispersed; If the temperature exceeds 1000°C to 1600°C, no separation will occur, and if the compound precipitation temperature falls outside the temperature range of 1000 to 1600°C, it will not be possible to secure the desired wear resistance and impact resistance. The compound precipitation treatment temperature is increased from the point to 10
It was set as 00:00 to 1600:00.

Next, the dawning material of the present invention and its manufacturing method will be specifically explained with reference to Examples. Example 1 TIC having an average particle size of 1.0×m as a raw material powder
Powder, 1.2m of (Tio. Strong Wo. Rudder) C powder,
1.5 m of ZrC powder, 1.0 m of (Japan et al. 4)
5N~. Mother) C powder, 1.2 fm TaC powder, 1
．． Prepare TiB2 powder of 0.8 mm and W powder of 0.8 mm, mix two or more of these raw material powders to a predetermined composition, wet mix in a ball mill for 7 hours, and dry. After that, it is press-molded at a pressure of 15k9 to form a green compact, and then this green compact is heated in a specific air flow at a temperature of:
After pre-sintering by holding at 800℃ for 1 hour, 10-
The temperature was maintained at 260,000 for 1 hour in a vacuum of 200,000 ton.
By performing compound precipitation treatment under the conditions of cooling at a cooling rate of 700oo/hr and holding at 1500qo for 3 hours in the temperature range up to 6 and comparison materials 1 to 6
were manufactured respectively.

In addition, Hisame Sintered Materials 1 to 6 all have compositions in which the content of any one of the constituent components (those marked with * in Table 1) is outside the scope of this invention. It is something that we have.

Next, a cutting tip having a shape of SNP432 was prepared from each of the fired materials 1 to 6 of the present invention and Hisame sintered materials 1 to 6 obtained as a result, and the work material was JIS/SN.
CM-8 (hardness: HB260), cutting speed: 20 skin/m
continuous high-speed cutting test under the conditions of in, feed: 0.3 ribs/rev, depth of cut: 2 ribs, cutting time: 1 minute, work material: JIS/SNCM-8 (hardness: HB280), cutting speed , 180 skin/min, feed rate: 0.2 side, depth of cut: 2 ribs, and cutting time: 3 minutes. Intermittent high-speed cutting tests were conducted under the conditions of , 180 skin/min, feed: 0.2 side, cutting depth: 2 ribs, and cutting time: 3 minutes.In the continuous high-speed cutting tests, flank wear depth and crater wear on the chip cutting edge were measured. The depth was measured, and in the intermittent high-speed cutting test, the number of cutting edges in which breakage occurred out of the number of cutting edges tested was measured.

These measurement results are also shown in Table 1. In addition, the first
For comparison purposes, the table shows a ceramic cutting tip whose main component is mountain oxide, and Ti carbide (TIC) produced by chemical vapor deposition on the surface of a cemented carbide substrate whose main component is W carbide.
Also shown are cutting test results under the same conditions for surface-coated cemented carbide cutting tips (referred to as conventional cutting tips 1 and 2) coated with AI oxide (Mountain 203) with a total average layer thickness of 7 mm. As is clear from the results shown in Table 1, conventional cutting tip 1 had particularly poor impact resistance, resulting in fractures on all of the test cutting edges, and conventional cutting tip 2 had excellent impact resistance. Therefore, although it shows excellent cutting performance equivalent to the sintered material of the present invention in an intermittent high-speed cutting test, it suffers from large wear in a continuous high-speed cutting test due to inferior wear resistance.

On the other hand, it is clear that the aged materials 1 to 6 of the present invention exhibit excellent high-speed cutting performance in both intermittent and continuous high-speed cutting tests. Furthermore, as seen in Hisame Sintered Materials 1 to 6, when the content of any one of the constituent components falls outside the scope of the present invention, the cutting test is inferior in at least one of the continuous and intermittent high-speed cutting tests. It will show you the results. Example 2 In addition to the raw material powder used in Example 1, the average particle size:
1. Kanono (Tio.58Wo.42) CO. short powder,
And the same 1.0w enemy TIC Misaki horse. 5 powders are prepared, and these raw material powders are appropriately combined and used to form a predetermined composition,
This blended powder was mixed under the same conditions as in Example 1, press-molded, and pre-sintered, then 10-2
ton of vacuum at a temperature of 2,100°C for 2 hours, and after brining, it was cooled at a cooling rate of 700 qo/hr in the temperature range from the competitive coalescence temperature to 1,200 qo while maintaining a solid solution structure. , 1200 qo for 5 hours to perform a compound precipitation treatment, the present invention materials 7 to 10 having the component compositions shown in Table 2, and the content of any one of the constituent components (second Hisame sintered materials 7 to 11 (those marked with * in the table) having compositions outside the scope of the present invention were manufactured, respectively.

Next, cutting chips each having a shape of SNP432 were prepared from the above-mentioned sintered materials 7 to 10 of the present invention and Hisame sintered striped materials 7 to 11.
(hardness: HB250), cutting speed: 80/min, feed: 0.75 ribs/rev, depth of cut: 8 skins, cutting time: 1
A continuous high-feed cutting test was conducted under perfect conditions, and flank wear depth and crater wear depth were measured.

The measurement results are shown in Table 2. Table 2 also shows, for the purpose of comparison, a hard layer of Ti carbide coated with an average layer thickness of 6 Am by chemical vapor deposition on the surface of a commercially available anchor hard alloy substrate mainly composed of W carbide. surface-coated cemented carbide cutting tips consisting of P30 W carbide as a main component (hereinafter referred to as conventional cutting tips 3 and 4).
The results of cutting tests under the same conditions are also shown.

As shown in Table 2, the results were similar to those in Example 1, and the cutting tips made with the inventive sintering materials 7 to 10 were the same as the cutting tips 3 and 4 of the subordinate cutting tips 3 and 4 and the comparative sintering materials. It is clear that the cutting performance is much superior to that of the cutting tips prepared in Examples 7 to 11.

As described above, according to the present invention, a sintered material with excellent high-temperature properties, Table 2, that is, wear resistance, plastic deformation resistance, oxidation resistance, and impact resistance is produced using a conventional powder metallurgy method. Therefore, when the resulting material is used as a cutting tool for high-speed cutting or high-feed cutting that requires the above-mentioned high-temperature properties, it exhibits extremely excellent cutting performance.

Claims (1)

[Claims] 1 Ti: 5-25%, one or two of Zr and Hf: 5-20%, one or two of Nb and Ta: 5-20%, C: 15-40%, B: 1-1
0%, and the rest is W and unavoidable impurities (however, W: 2
0 to 55%) (in atomic %),
and the dispersed phase consists of a fine hard phase consisting of a compound phase mainly composed of Ti, C and B, and a compound phase mainly composed of one or two of Zr and Hf and C and B. , on the other hand, a sintered material for cutting tools having excellent high-temperature properties, characterized in that the binder phase has a structure consisting of a W-based alloy containing W as a main component. 2. Prepare metal carbide powder, metal boride powder, metal carboride powder, and W powder as raw material powders, mix two or more of these raw material powders to a predetermined composition, and mix under normal conditions. The resulting green compact is mixed and press-molded in a non-oxidizing atmosphere at a temperature of 2000 to 27
After complete solid solution sintering at a high temperature of 00°C, compound precipitation treatment is performed at a temperature of 1000 to 1600°C in a non-oxidizing atmosphere, Ti: 5 to 25%, one or two of Zr and Hf: 5 ~20%, one or two of Nb and Ta: 5-20%, C: 15-40%, B: 1-1
0%, and the rest is W and unavoidable impurities (however, W: 2
0 to 55%) (in atomic %),
and the dispersed phase consists of a fine hard phase consisting of a compound phase mainly composed of Ti, C and B, and a compound phase mainly composed of one or two of Zr and Hf and C and B. A method for producing a sintered material for a cutting tool with excellent high-temperature properties, characterized in that the binder phase produces a sintered material having a structure consisting of a W-based alloy containing W as a main component.