JPS621464B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention has high toughness and hardness, as well as excellent wear resistance, plastic deformation resistance, and impact resistance. Cutting tools used for heavy cutting such as cutting and deep-cut cutting, as well as cutting tools used for relatively long and high temperatures such as hot rolling rolls, hot drawing rolls, hot compression dies, hot forging dies, and hot extrusion punches. The present invention relates to a super heat-resistant sintered alloy that exhibits excellent performance when used as a hot working tool exposed to heat, and a method for producing the same. In recent years, high-speed cutting and high-feed cutting have been considered in order to improve machining efficiency, but increasing the cutting speed or feed rate increases the temperature of the cutting tool's cutting edge and causes the cutting edge to wear out. Rather, in many cases, the service life is reached due to plastic deformation caused by high temperatures. However, the hard phase currently in practical use is mainly tungsten carbide (hereinafter referred to as WC).
and titanium carbide (hereinafter referred to as TiC), while the binder phase is mainly composed of iron group metals.
WC-based cemented carbide and TiC-based cermet suddenly soften when the cutting edge temperature exceeds 1000°C. Even for those with a coating layer, the usage conditions are limited to a blade edge temperature of slightly over 1000°C. In addition, the hard phase is composed of a composite carbide solid solution of Ti and W (hereinafter referred to as (Ti, W)C) or a composite carbonitride solid solution (hereinafter referred to as (Ti, W)CN), while the binder phase A cermet composed of a W-Mo alloy has been proposed, and attempts have been made to use this cermet as a cutting tool for high-speed cutting and heavy-duty cutting, but this conventional cermet has poor sinterability and is difficult to use as a raw material powder. be done (Ti,
Because the C concentration in the W)C powder or (Ti, W)CN powder is relatively high, a part of it reacts with a part of the W powder during sintering to form brittle W ₂ C, and this W ₂ C The presence of these materials results in poor impact resistance, and the current situation is that they do not exhibit sufficiently satisfactory cutting performance. Therefore, from the above-mentioned viewpoints, the present inventors have developed a method that has particularly excellent plastic deformation resistance and impact resistance.
As a result of conducting research to develop materials suitable for use as cutting tools for high-speed cutting and heavy cutting of steels that require wear resistance, we found that Ti carbides, nitrides, and Powder of one or more types of carbonitrides (hereinafter referred to as TiC, TiN, and TiCN, collectively referred to as Ti carbon/nitride): 50 ~
30%, Zr and Hf carbides, nitrides, and carbonitrides (hereinafter ZrC, ZrN, ZrCN, respectively)
Powder of one or more of HfC, HfN, and HfCN, collectively referred to as (Zr, Hf) carbon/nitride: 5 to 35%, magnesium oxide (hereinafter referred to as MgO) ) Powder: 0.5 to 10%, W powder: remainder, powder of one or more of TiC, TiN, and TiCN: 5 to 30%, ZrC, ZrN, ZrCN, HfC, HfN, and
Powder of one or more types of HfCN: 5
~35%, MgO: 0.5-10%, powder of one or two of aluminum oxide (hereinafter referred to as Al ₂ O ₃ ) and yttrium oxide (hereinafter referred to as Y ₂ O ₃ ): 0.5-10%, W powder: The remaining powder compact with a blending composition of
In vacuum or inert gas atmosphere, 1800~
When sintered at a high temperature within the range of 2700°C, a composite carbide solid solution and a composite carbonitride solid solution (hereinafter referred to as (Ti, W, Zr, Hf)C and (Ti,
Any one of W, Zr, Hf) (indicated by CN)
Seeds: 10-60%, MgO as a hard phase forming component: 0.01
~1%, W as a binder phase forming component and unavoidable impurities: the remainder, (Ti, W, Zr,
Any one of Hf)C and (Ti, W, Zr, Hf)CN: 10 to 60%, MgO as a hard phase forming component: 0.01 to 1
%, Al ₂ O ₃ and also as hard phase forming components
One or two of Y ₂ O ₃ : 0.5 to 10%, W as a binder phase forming component and unavoidable impurities: the remainder, the above composition, and the above (Ti,
W, Zr, Hf)C and (Ti, W, Zr, Hf)CN
However, a super heat-resistant sintered alloy with a two-phase structure of a phase rich in Ti and W and a phase rich in either or both of Zr and Hf is obtained, and in this super heat-resistant sintered alloy, during sintering, , MgO, (Ti, W, Zr, Hf)C and (Ti,
W, Zr, Hf) CN (hereinafter collectively referred to as composite carbon/nitride solid solution) reacts with the C component in this composite carbon/nitride solid solution, and the C component in this composite carbon/nitride solid solution decreases. As a result, sintering properties are significantly improved, and brittle W ₂ C is difficult to form, resulting in excellent impact resistance.Furthermore, the composite carbon/nitride solid solution as a hard phase As mentioned above, it has a two-phase structure of a fine phase rich in W and Ti and a fine phase rich in either or both of Zr and Hf, which further improves wear resistance and plastic deformation resistance. Therefore, it was found that when used as a cutting tool for high-speed cutting or heavy cutting, it exhibits excellent cutting performance. This invention has been made based on the above findings, and the reason why the blending composition, component composition, and sintering temperature are limited as described above will be explained below. (a) Composite carbon/nitride solid solution This component is the main hard phase forming component, and has the effect of imparting excellent wear resistance and plastic deformation resistance to the sintered alloy, and this hard phase teeth,
It is formed by blending Ti carbon/nitride powder and (Zr, Hf) carbon/nitride powder as raw material powder, but if the blending amount is less than 5% each, the composite carbon/nitride powder Solid solution content is 10%
On the other hand, in the case of Ti carbon/nitride powder, the desired effect cannot be obtained.
%, and in the case of (Zr, Hf) carbon/nitride powder, exceeds 35%, the content of the composite carbon/nitride solid solution becomes too high, exceeding 60%, Since the toughness of the sintered alloy will be significantly reduced, the amount of Ti carbon/nitride powder should be increased to 5-30%, and the amount of (Zr, Hf) carbon/nitride powder should be increased to 5-35%. The content of the composite carbon/nitride solid solution in the sintered alloy was determined to be 10 to 60%. (b) MgO During sintering, most of MgO reacts with C in the composite carbon/nitride solid solution formed in this sintering process, reducing the amount of C in the composite carbon/nitride solid solution. At the same time, it improves sinterability, and a small amount of it remains in the sintered alloy and has the effect of significantly improving impact resistance, but if the amount is less than 0.5%, the desired sinterability improvement is not achieved. Not only is there no effect, but the amount of MgO remaining in the sintered alloy is 0.01
If the MgO content exceeds 10%, the MgO content in the sintered alloy will exceed 1% if the sintering temperature is low. As a result, not only the plastic deformation resistance of the sintered alloy decreases, but also cavities are more likely to form in the sintered alloy, resulting in a deterioration of its impact resistance. from,
The blending amount of MgO was determined to be 0.5 to 10%, that is, the MgO content was determined to be 0.01 to 1%. (c) Al ₂ O ₃ and Y ₂ O ₃ Most of these components are uniformly dispersed in the matrix, improving sinterability and further improving the wear resistance and impact resistance of the sintered alloy. Since it has the effect of improving the effect, it is blended (contained) as necessary, but if the blended (contained) amount is less than 0.5%, the desired effect of improving the above effect cannot be obtained; %, the impact resistance and plastic deformation resistance of the sintered alloy tend to deteriorate.
It was set at 10%. (d) W and unavoidable impurities A part of W is solidly dissolved in the hard phase, but most of it is present as a binder phase and is strongly bonded to the hard phase.
It has the effect of imparting excellent impact resistance to the sintered alloy. In addition, as an unavoidable impurity
Even if it contains one or more of Mo, Cr, Fe, Ni, Co, Re, Pt, and Pd, the characteristics of the sintered alloy will be affected if the content of each component is 1% or less. Nothing will be harmed. (e) Sintering temperature If the sintering temperature is less than 1800°C, the evaporation of MgO will be insufficient, and therefore the amount of carbon in the sintered alloy will decrease less, making it difficult to secure the desired sinterability and impact resistance. On the other hand, if the sintering temperature exceeds 2700℃, a liquid phase will occur in the sintered alloy and its shape will change.
The temperature was set at 2700℃. Next, the super heat-resistant sintered alloy of the present invention will be specifically explained with reference to Examples. Example 1 Raw material powder has an average particle size of 1.5 μm
TiC powder, 1.2μm TiN powder, 1.0μm ZrC
Prepare powder, HfC powder of 1.5 μm, MgO powder of 0.4 μm, Al ₂ O ₃ powder of 0.5 μm, Y ₂ O ₃ powder of 0.4 μm, and W powder of 0.8 μm, and use these raw materials. Each powder was blended into the composition shown in Table 1, wet-pulverized and mixed in a ball mill for 72 hours, dried, and then press-molded at a pressure of 15 kg/mm ² to form a green compact. The sintered alloy 1 of the present invention having the component composition also shown in Table 2 was obtained by sintering the body in a nitrogen atmosphere of 760 torr under the conditions of holding the temperature shown in Table 1 for 2 hours. ~31 and comparative sintered alloys 1 to 5 were manufactured respectively.

【table】

【table】

【table】

【expressed. Next, the resulting sintered alloys of the present invention 1-
31 and Comparative Sintered Alloys 1 to 5 were measured for their hardness (Rockwell hardness A scale) and transverse rupture strength, and cutting chips with the shape of SNP433 were cut from them. Work material: SNCM-8 (hard). _Cutting speed: 200 m/min, Feed: 0.3 mm/rev., Depth of cut: 2 mm, Cutting time: 10 min, High-speed continuous cutting test under the following conditions, and Work material: SNCM-8 ( Hardness: H _B 270), Cutting speed: 120m/min, Feed: 0.4mm/rev., Depth of cut: 3mm, Cutting time: 3min. The flank wear width and rake face wear depth of the blade were measured, and in the above interrupted cutting test,

【table】

[Table] Among the 10 test cutting edges, the number of cutting edges with chipping was measured. The results of these measurements are shown in Table 3. For comparison purposes, an ISO P10 grade WC-based cemented carbide cutting tip (hereinafter referred to as conventional cutting tip 1) and TiC-10%Mo-15%
A cutting test was also conducted under the above cutting conditions for a TiC-based cermet cutting tip (hereinafter referred to as conventional cutting tip 2) having a composition of Ni (the above weight %, below % indicates weight %), and the results are also shown in Table 3. It was shown to. As is clear from the results shown in Table 3, all of the sintered alloys 1 to 31 of the present invention have high hardness and high toughness, and exhibit excellent wear resistance and impact resistance in all cutting tests. In contrast, comparative sintered alloy 1 containing no MgO and (Ti, W,
Comparative sintered alloys 2 and 3 that do not contain Zr)C have inferior sintering properties and impact resistance, so in continuous cutting tests in particular, all or most of the cutting edges were damaged, and Comparative sintered alloys 4 and 5, in which the content of (Ti, W, Zr)C is higher than the range of the present invention, show relatively excellent wear resistance but have poor toughness. In the interrupted cutting test, most of the cutting edges were damaged. Furthermore, it is clear that the conventional cutting chips 1, 2 have poor wear resistance and impact resistance, and exhibit very poor cutting performance. Example 2 In addition to the raw material powder used in Example 1, as raw material powders, TiC _0.7 N _0.3 powder with an average particle _size of 1.5 μm, TiC _0.6 N _0.4 powder with _an average particle _{size of} 1.2 μm, 1.0 μm
TiC _0.5 N _0.5 powder, _1.5 μm TiC _{0.4 N 0.6 powder ,}
1.2 μm ZrC _0.7 N _0.3 powder and 1.0 μm ZrC 0.7 N _0.3 powder _.
HfC _0.7 N _0.3 powder ₍ weight ratio above) was prepared, these raw _material powders were blended into the composition shown in Table 4, and then wet-pulverized and mixed under the same conditions as in Example 1. By drying, molding to form a compact, and then sintering at a temperature of ₂₀₀₀ °C for 2 hours in an N2 gas or Ar gas atmosphere at various pressures shown in Table 4, Sintered alloys 32 to 49 of the present invention having the component compositions shown in Table 5 were manufactured, respectively.

【table】

[Table] Next, the resulting sintered alloys of the present invention 32~
49, the hardness and transverse rupture strength were measured, and cutting chips with the shape of SNP433 were cut from this, and ISO chips prepared for comparison purposes were also measured.
Along with P30 grade WC-based cemented carbide cutting tips (hereinafter referred to as conventional cutting tips), workpiece material: SNCM-8 (hardness: H _B 265), cutting speed: 100m/min, feed: 0.8mm/rev. , Depth of cut: 4 mm, Cutting time: 10 min, High feed continuous cutting test under the conditions of , Work material: SNCM-8 (hardness: H _B 275), Cutting speed: 100 m/min, Feed: 0.45 mm/ An interrupted cutting test was conducted under the following conditions: rev., depth of cut: 3 mm, cutting time: 3 min, and as in Example 1, the flank wear width and rake face wear depth of the cutting edge, as well as the number of missing cutting edges, were measured. measure

[Table] These measurement results are also shown in Table 6. From the results shown in Table 6, the present invention sintered alloy 32
-49 all have high hardness and high toughness, and show excellent cutting performance in high-feed continuous cutting and interrupted cutting, whereas conventional cutting tip 3 has particularly poor plastic deformation resistance, so it is difficult to use high-feed cutting. In a continuous cutting test, it became impossible to cut after 3 minutes. Example 3 In addition to the powder used in Example 1, as a raw material powder, Mo with an average particle size of 0.8 μm was added as an impurity.
powder, 2.5μm Ni powder, 1.2μm Co powder,
After preparing the same 3.0 μm Re powder and blending these raw powders into the compositions shown in Table 7, they were wet-pulverized and mixed under the same conditions as in Example 1, dried, molded, and pressed. powder, and then these green compacts in a nitrogen atmosphere of 300 torr,
Sintered alloys 50 to 79 of the present invention and comparative sintered alloys 6 to 6, each having the composition shown in Table 8, were obtained by sintering them at the temperatures shown in Table 6 for 2 hours. 13 were produced respectively.

【table】

【table】

【table】

[Table] Next, hardness and transverse rupture strength were measured for these sintered alloys 50 to 79 of the present invention and comparative sintered alloys 6 to 13, and cutting chips with the shape of SNP433 were cut from them. Furthermore, along with an ISO P40 grade WC-based cemented carbide cutting chip (hereinafter referred to as conventional cutting chip 4) prepared for comparison purposes, workpiece material: SNCM-8 (hardness: H _B 265), cutting speed: 60 m /min, Feed: 0.7mm/rev., Depth of cut: 10mm, Cutting time: 3min, High feed continuous cutting test under the following conditions, Work material: SNCM-8 (Hardness: H _B 275), Cutting speed An interrupted cutting test was conducted under the following conditions: : 80 m/min, feed: 0.5 mm/rev., depth of cut: 3 mm, cutting time: 3 min, and as in Example 1, the width of flank wear of the cutting edge and

【table】

[Table] The wear depth of the rake face and the number of chipped cutting edges were measured. These measurement results are also shown in Table 9. From the results shown in Table 9, the present invention sintered alloy 50
-79 all have high hardness and high toughness, and show excellent performance in all cutting tests.In particular, as seen in the present invention sintered alloys 56-59 and 76-79, Mo, Ni It is clear that even if impurities such as , Co, or Re are contained, if the content is 1% or less, the properties of the sintered alloy are hardly affected. On the other hand, Comparative Sintered Alloys 6 and 7 have a blending (content) amount of MgO or Al ₂ O ₃ that is outside the range of the present invention, and Comparative Sintered Alloys 6 and 7 have a content of composite carbon/nitride solid solution that is outside the range of the present invention. Comparative sintered alloys 8 and 9 are on the lower side, comparative sintered alloys 10 and 11 have a high content of Ni as an impurity, exceeding 1%,
Furthermore, Comparative Sintered Alloys 12 and 13, which were manufactured at a low sintering temperature outside the range of the present invention, both exhibited extremely poor cutting performance due to insufficient toughness, and the conventional cutting tip 4 exhibited extremely poor cutting performance. Although it had excellent impact resistance almost equivalent to that of the sintered alloy of the present invention, it was inferior in plastic deformation resistance and could not be cut in 0.8 minutes in a high-feed continuous cutting test. As mentioned above, the super heat-resistant sintered alloy of this invention is
It has high toughness and hardness, as well as excellent wear resistance, plastic deformation resistance, and impact resistance.
It exhibits excellent cutting performance when used as a cutting tool for high-speed cutting and heavy cutting of steel that require these characteristics, and is also suitable for hot rolling rolls, hot drawing rolls, hot compression dies, hot forging. It has industrially useful properties such as exhibiting excellent performance over a long period of time when used as a hot processing tool such as a die or even a hot extrusion punch that is exposed to high temperatures for a relatively long period of time.

Claims (1)

[Claims] 1 Any one of a composite carbide solid solution and a composite carbonitride solid solution of Ti, W, and one or two of Zr and Hf as hard phase forming components: 10 -60%, magnesium oxide as a hard phase forming component: 0.01 to 1%, W as a binder phase forming component and unavoidable impurities: the remainder (weight%), and the above composite carbide solid solution and composite carbonitride solid solution,
It has a two-phase structure of a phase rich in Ti and W and a phase rich in either or both of Zr and Hf.It has high toughness and hardness, and has good wear resistance and plastic deformation resistance. , and a super heat-resistant sintered alloy with excellent impact resistance. 2 Any one of composite carbide solid solutions and composite carbonitride solid solutions of Ti as hard phase forming components, W, and one or two of Zr and Hf: 10 to 60%, also hard Magnesium oxide as a phase-forming component: 0.01 to 1%, and one or two of aluminum oxide and yttrium oxide as hard phase-forming components.
Species: 0.5 to 10%, W as a binder phase forming component, and unavoidable impurities: the remainder (weight%), and the above composite carbide solid solution and composite carbonitride solid solution,
It has a two-phase structure of a phase rich in Ti and W and a phase rich in either or both of Zr and Hf.It has high toughness and hardness, and has good wear resistance and plastic deformation resistance. , and a super heat-resistant sintered alloy with excellent impact resistance.