JPH0312144B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to surface-coated cermet members for cutting tools and wear-resistant tools, and in particular, a bonding alloy having a martensitic structure containing fine particles of a titanium compound and a vanadium compound as a hard dispersed phase. The present invention relates to a surface-coated cermet member for cutting tools and wear-resistant tools, which has a super hard coating layer made of a titanium compound on the surface of the cermet. [Conventional technology] Conventionally, high-speed steel (hereinafter referred to as high speed steel) has high hardness and excellent toughness, so it has been widely used not only for cutting tools but also as a material for various wear-resistant tools that require wear resistance. However, in order to further extend the life of these tools, recently cermets have been developed in which carbides and nitrides of various metals, which contribute to improved wear resistance, are dispersed in HSS using a sintering method. On the other hand, if an ultra-hard coating layer made of a titanium compound is provided on the surface of the high speed steel, the welding resistance and seizure resistance will be improved, and the tool life will be extended by 2 to 30 minutes.
Since the length is 10 times longer, providing such a coating layer on the surface of high speed steel has also been widely adopted industrially. [Problems to be Solved by the Invention] Titanium carbide, which is a typical metal carbide, improves the sinterability of cermet during sintering, and remains dispersed in the structure of cermet after sintering. Titanium nitride, which is a typical metal nitride, remains dispersed in the cermet structure after sintering and improves the welding and seizure resistance of the cermet. However, if a large amount of titanium nitride is dispersed in the bonding metal, the toughness of the cermet will decrease, so there is a limit to the amount of titanium nitride added. There was a natural limit to the improvement of seizability. On the other hand, even with the above-mentioned coating with the ultra-hard layer, the extension of tool life was not necessarily satisfactory for the following reasons. (1) The coating treatment for the above coating layer is carried out at a temperature below the tempering temperature of the high speed steel, that is, usually at a temperature around 500°C. If a tool provided with this coating layer is used, the coating layer is likely to peel off. (2) In addition, even after the above-mentioned tools have been used for a certain period of time, they are partially re-sharpened and used repeatedly. In this case, the remaining coating layer is useful for extending the tool life, so this re-sharpening is recommended. Although the life of a coated HSS tool is improved compared to an uncoated HSS tool, the wear resistance of the exposed base material surface due to the loss of the coating layer due to re-sharpening will eventually reduce the tool life. Therefore, the effect of improving tool life with the ultra-hard coating layer is not constant in each actual operation. Therefore, even if an attempt is made to extend the tool life using such a super-hard coating layer, the effect is unstable and unpredictable, so it is difficult to confirm its effectiveness in individual cases in actual work before deciding on its application. The current situation is that [Means for solving the problem] Therefore, from the above-mentioned viewpoint, the present inventors have solved the problem.
In order to improve the tool life of surface-coated members for cutting tools and wear-resistant tools, in which the surface of a cermet, in which hard particles are dispersed in a high-speed steel master alloy having a martensitic structure, is coated with an ultra-hard layer, various As a result of repeated research, we found the following findings: () At a coating temperature of approximately 500°C, the diffusion distance of atoms during vapor deposition of the coating material is extremely short, and titanium atoms are difficult to diffuse into the iron-based substrate. Therefore, strong adhesion cannot be obtained between the coating layer made of a titanium compound and the iron-based substrate, whereas if a dispersed phase made of a titanium compound exists in this substrate, the dispersed phase and the coating phase Rearrangement of titanium atoms occurs at the bonding surface, forming a structure in which the titanium dispersed phase and the coating phase are integrated via titanium atoms, that is, a structure in which the coating layer is rooted in the substrate. In order to create a strong bonding force between the coating layer and the substrate and to exert that bonding force strongly over the entire joint surface, the content of the titanium compound in the cermet must be 5% by weight or more; () Titanium nitride (hereinafter referred to as titanium nitride) dispersed in the bonding alloy
If the average particle size of TiN) and/or TiCxNy (where x<y) particles is set to 5 μm or less, sinterability is improved, so 5 to 20% by volume
() Therefore, the content of TiN and TiCxNy (x<y) can be increased without reducing the toughness of the cermet, and these are Because it has strong adhesion and seizure resistance, even if the base is exposed on the tool surface by re-sharpening a part of the tool in use, the base itself will not be damaged by conventional high-speed steel or Compared to cermet, it has superior welding and seizure resistance, and its wear resistance is well balanced with the excellent wear resistance of the coating layer, resulting in a stable tool life for the tool as a whole. I found out that it can be done. This invention was invented based on the above findings, and includes: first particles that are one or two particles of TiN and NiCxNy (where x<y) with an average particle size of 5 μm or less: D1 and vanadium carbide (hereinafter referred to as VC) of 5μm or less and (Vx, My)C
(However, M is Ti, Zr, Hf, Nb, Ta, Cr, Mo,
A dispersed phase consisting of second particles: D2, which are one or more elements selected from W and are one or two particles of x>y), and Cr: 3.5. ~6%, W+Mo: 4~20%, V: 3~
6%, Co or Co+Ni (however, Ni/Co+Ni: 3
% or less): 2-15%, C: 0.5-2.0%, and Fe
+ unavoidable impurities: a cermet consisting of a binder phase having a martensitic structure that has undergone heat treatment of quenching and tempering (hereinafter referred to as weight %), and with respect to D1, D2 and the binder phase. The composition is D1: 5-20% by volume,
D2: 5 to 30% by volume and binder phase: the remainder The cermet is used as a base, and the surface of the base is coated with Ti, dititanium mononitride,
_Ti2N ), Tin and TiCxNy (where x<
A single layer consisting of any one of y) (excluding the case of Ti), a composite layer consisting of two or more of these, or a combination of one or more of each of these single layers and composite layers. Multi-layered Bitkers hardness Hv: 2000Kg/mm ² or more Thickness: 1
The present invention provides a surface-coated cermet member for cutting tools and wear-resistant tools, which is provided with an ultra-hard coating layer of ~10 μm. Next, in this invention, the reason why the component composition range, particle size, Vickers hardness and layer thickness of the coating layer are limited as described above will be described. A Base (a) Binding phase The master alloy forming the binding phase is Cr: which is obtained by sintering powdered high speed steel.
3.5~6%, W+Mo: 4~20%, V: 3~6
%, Co or Co+Ni (however, Ni/Co+Ni:
3% or less): 2 to 15%, C: 0.5 to 2.0%, and Fe + unavoidable impurities: the remainder (weight %), and the composition range of these individual components is suitable for high speed steel. However, for Co, Part 3
Up to % by weight can be replaced with Ni.
Ni has the function of increasing the amount of retained austenite after heat treatment, but in this invention, in order for the dispersed phase to exhibit sufficient hardness and wear resistance, the hardness of the alloy itself constituting the binder phase is lower than that of the alloy itself after heat treatment. It is permissible for the hardness to be slightly lower than that of high speed steel. This bond master alloy has a martensitic structure that has been quenched and tempered, and also contains fine M ₆ C type carbides and, in some cases (particularly when Ni is included), a small amount of retained austenite structure. (b) Dispersed phase D1 Titanium nitride: TiN and titanium carbonitride:
TiCxNy is originally an effective component for imparting high hardness and wear resistance to various tools, and as mentioned above, the Ti contained in these compounds can cause damage to the coating at the bonding surface between the base and the coating layer. Because it causes rearrangement with Ti in the layer components and strengthens the bond between the substrate and the coating layer,
It is a component that plays an important role in firmly adhering the coating layer made of titanium compounds to the substrate, but if the amount of the dispersed phase made of these compounds is less than 5% by volume, the above bond cannot be maintained strongly. On the other hand, if the content exceeds 20% by volume, the toughness of the entire substrate decreases, so the content was set at 5 to 20% by volume. In addition, if the average particle size of the particles of these compounds exceeds 5 μm,
Since the toughness of the substrate decreases, it is set at 5 μm or less, and in order to provide sufficient adhesion resistance and seizure resistance to the substrate with TiCxNy, it is necessary to
Since a large amount must be included, it was determined that x<y. (c) Dispersed phase D2 Vanadium carbide: VC and vanadium
Composite carbide with one or more metals from Ti, Zr, Hf, Nb, Ta, Cr, Mo, and W: (Vx, My)C (where M represents the above metal, and z>y ) is originally an effective component for imparting high hardness and wear resistance to various tools, and V contained in these carbides.
and V in the bonding mother alloy, which has the effect of increasing the interfacial strength between the carbide and the bonding mother alloy and improving toughness, but in the case of the above composite carbide, the proportion of metal M other than V is V
(Vx, My)C is set as x>y because if the ratio exceeds (in atomic ratio), the sea surface strength of the carbide and the binder phase weakens and the toughness of the base material decreases. In addition, if the average particle size of these carbide particles exceeds 5 μm, the toughness of the base will decrease, so it is set at 5 μm or less,
Furthermore, the amount of the dispersed phase consisting of these carbides is 5
If it is less than 30% by volume, the above-mentioned effect of improving wear resistance due to carbide cannot be expected. On the other hand, if it exceeds 30% by volume, the toughness and oxidation resistance of the base material will decrease.
It was determined as capacity%. B Layer thickness and hardness of ultra-hard coating layer As mentioned above, the coating layer is composed of one or more of the titanium compounds consisting of Ti ₂ N, TiN, and TiCxNy (x<y), or these titanium compounds and Ti. These titanium compounds form an ultra-hard layer, while Ti alone, i.e. in the form of a single layer of Ti,
Although it is not possible to form a coating layer of the carbide chamber,
When these titanium compounds are interposed between each layer or between each of these layers and the substrate, it has the effect of increasing the adhesion between these layers, and titanium carbonitride
The reason for setting x<y in TiCxNy is the above A.
As stated in paragraph (c) of Here, a composite layer refers to two layers in which all the layers are different from each other, such as a layer consisting of TiN+TiCN or TiN+TiCN.
A multilayer refers to a layer consisting of more than one component, such as a TiN+Ti+TiN layer, which is a stack of a TiN single layer and a TiCN+TiN composite layer.
It means a layer consisting of two or more types of components and three or more layers, in which layers made of one or more types of components are repeatedly stacked on each other twice or more. If the thickness of the coating layer is less than 1 μm, sufficient improvement in wear resistance cannot be obtained;
Even if the thickness exceeds 10 μm, there is little improvement in wear resistance, and rather the toughness of the entire member deteriorates significantly, so the layer thickness was set at 1 to 10 μm. In addition, the hardness of the coating layer is 2000 as measured by a micro-Vickers hardness tester.
Since the desired wear resistance cannot be achieved with Kg/mm ² , the hardness was set at 2000 Kg/mm ² . The surface-coated cermet member of the present invention is produced by mixing high-speed steel powder with nitride powder and carbide powder, press-molding the mixed powder to form a green compact, and then molding it in vacuum or in a non-oxidizing atmosphere. After sintering, removing residual pores by HIP treatment if necessary, quenching and tempering, and polishing to obtain a substrate of specified dimensions, conventional chemical vapor deposition or physical vapor deposition is performed. It can be obtained by depositing a titanium compound or titanium and titanium on the surface of a substrate by a method. [Example] Next, the surface-coated cermet member of the present invention will be specifically explained with reference to Examples. Example 1 Cr: 4.0%, V: 3.2%, Mo: 5.0%, W: 5.0
%, Co: 9.0%, C: 1.1% and Fe + unavoidable impurities: remainder (weight %), average particle size adjusted by atomization:
These raw material powders were blended at a blending ratio of 90% by volume of 5μm high speed steel powder, 5% by volume of 1.0μm TiN powder, and 5% by volume of 1.1μm (V _0.95 , Ti _0.05 )C powder, and then ball milled for 24 hours. After wet mixing and pulverization, drying, press forming at a press pressure of 3.0 ton/mm ² to form a green compact, and then sintering the green compact by holding it in a vacuum at a temperature of 1270°C for 1 hour. , furthermore, in argon at 1000 atmospheres, temperature: 1230℃
A dense cermet was obtained by performing HIP treatment under conditions where the cermet was maintained at When we observed the structure of this cermet, we found that it was TiN.
Content is 5.1% by volume, carbide mainly composed of vanadium:
(V _0.95 , Ti _0.05 ) The amount of C was 5.2% by volume, and thus the actual measurement after sintering was close to the blended value. Next, this cermet was oil quenched at a temperature of 1260°C, and then tempered twice at the same temperature of 550°C to give a Rockwell hardness C scale _HRC of 67.The cermet was then polished to a size of 8 x 12. ×4.8mm
A throw-away tip for a side cutter was manufactured. This throw-away chip, as well as a throw-away chip with the same dimensions as above, cut from commercially available SKH-9 types of high-speed steel manufactured by the melting method, were prepared using the ion plating method to achieve a Bitkers hardness of 2200 kg. /mm ² and a thickness of 3 μm at 500° C. to produce inventive coated cutting chips 1 and comparison coated cutting chips 1. Therefore, when an indenter of a Vickers hardness tester was driven into the surface of these cutting chips with a load of 20 kg, peeling of the TiN layer was observed in the square indentation of the comparison coated cutting chip 1, whereas peeling of the TiN layer was observed in the square indentations of the comparative coated cutting chip 1. No peeling was observed on the coated cutting chips. In addition, for half of these cutting chips, the rake face is polished so that only the flank surface remains with a coating layer, and the chips that are not polished are cut using a side cutter. Work material: JIS / SNCM-8 ( A continuous steel cutting test was conducted on a round bar with hardness: H _B 270) under the following conditions: cutting speed: 100 m/min, feed: 0.3 mm/rev・, depth of cut: 5 mm, and the amount of flank wear was measured. The tool life of each cutting tip was measured using the time when the value reached 0.3 mm as the tool life standard, and the results are shown in Table 1.

[Table] Example 2 Cr produced by a known method of co-reducing a mixture of various metal oxides and carbon with hydrogen:
4.0%, V: 3.0%, Mo: 8.0%, Co: 10%, C:
0.85% and Fe + unavoidable impurities: The remainder has a composition (more than weight %) of average particle size: 3.0 μm high speed steel powder, 3 μm and 6.2 μm TiN powder,
2.0 μm TiC _0.1 N _0.9 powder, 2.0 μm VC powder,
1.8 μm (V _0.9 Zr _0.1 ) C powder, 2.1 μm (V _0.95 , Hf _0.05 ) C powder, 2.0 μm (V _0.9 ,
Nb _0.1 ) C powder, 1.5 μm (V _0.95 , Ta _0.05 ) C
Powder, 1.3μm (V _0.8 , W _0.2 )C powder, 1.5μm
Prepare a (V _0.7 , Ma _0.3 ) C powder with a diameter of 1.3 μm and a (V _0.8 , Cr _0.2 ) C powder with a diameter of 1.3 μm, mix these raw powders into a predetermined composition, and wet-mix and grind them in a ball mill for 24 hours. After drying, it is press-molded at a press pressure of 2.0ton/ ^mm2 to form a green compact.
Next, each green compact was sintered in a vacuum at a temperature of 1280°C for 1 hour, and then sintered at a temperature of 1000°C.
Cermet members having the component compositions shown in Table 2 are manufactured by performing HIP treatment at a temperature of 1250°C in argon at atmospheric pressure, and then heated to 1250°C. After quenching and tempering at 540°C, a surface coating layer with the composition and average layer thickness shown in Table 2 was formed by ion plating at 500°C with various atmospheric gases. Coated cutting chips of the present invention as surface-coated cermet members having the shape of JIS.SNMN432 by forming them
No. 11 and comparative coated cutting chips 2-7 were prepared, respectively. Comparative coated cutting chips 2 to 7 are based on the content of any of the constituent components of the Izumo cermet (substrate) member, the average particle size of the titanium compound particles D1 in the dispersed phase, or the layer thickness of the coating phase. are outside the scope of this invention (all are indicated by * in Table 2). Next, a cutting test was conducted on the resulting cutting chips under the same conditions as in Example 1 to evaluate the tool life of each, and the resistance force of the cermet member was measured, and these results were used in a second test. Shown in the table. Example 3 Mixtures of various metal oxides and carbon are co-coated with hydrogen.

[Table] Cr produced by a known reduction method:
4.0%, V: 3.0%, W: 5.0%, Mo: 5.0%, Co:
10%, Ni: 1.0%, C: 1.1% and Fe + unavoidable impurities: the balance (weight%), average particle size: 3.0μm, high speed steel powder 85% by volume,
TiC _0.4 N _0.6 powder 5% by volume of 1.8μm and 2.0μm
After blending these raw powders at a blending ratio of 10% by volume of VC powder, a cermet was produced under the same conditions as in Example 1. The content of the first particles D1 of the dispersed phase in the obtained cermet, that is, particles having a composition of TiC _0.4 N _0.6 , was 5.2% by volume, and the content of the second particles D2,
That is, the content of VC particles was 10.2% by volume. A cermet with an _HRC hardness of 65 was obtained by subjecting this cermet to heat treatment under the same conditions as in Example 1, and for comparison purposes, a cermet similar to that in Example 1 was prepared from the same high speed steel as used in Example 1. An inventive coated cutting tip 12 and a comparative coated cutting tip 10 were manufactured. These cutting chips were then subjected to the same cutting test as in Example 1 to measure the tool life. The results are shown in Table 3.

[Table] [Effects of the Invention] According to the results of the Examples, the cermet member of the present invention contains TiN and/or TiCxNy particles, so that a hard coating layer made of a titanium compound can be firmly attached to the surface of the cermet member (Example). 1) By reducing the particle size of the titanium compound particles, these titanium It can be seen that by increasing the content of compound particles and improving the wear resistance of the base itself, the tool life of surface-coated cermet members was significantly extended (Tables 1 to 3). . As mentioned above, the surface-coated cermet member of the present invention has excellent wear resistance and peeling resistance, so the tool life is significantly improved, and therefore, when used as a cutting tool and a wear-resistant tool, It exhibits an excellent industrial effect in that excellent cutting performance can be stably maintained over a long period of time.

Claims (1)

[Claims] 1. Titanium nitride with an average particle size of 5 μm or less and
One or two of TiCxNy (x<y)
First particles, which are seed particles: D1 and vanadium carbide of 5 μm or less and (Vx, My)C (where M is selected from Ti, Zr, Hf, Nb, Ta, Cr, Mo, and W) A dispersed phase consisting of second particles: D2, which are one or more metals and are one or two particles of x>y), Cr: 3.5 to 6%, W + Mo: 4 ~20%, V:3~
6%, Co or Co+Ni (however, Ni/Co+Ni: 3
% or less): 2 to 15%, C: 0.5 to 2.0%, Fe + unavoidable impurities: the remainder (hereinafter referred to as weight %), a binder phase having a martensitic structure that has undergone heat treatment of quenching and tempering, A cermet consisting of D1, D2 and a binder phase whose composition is D1: 5-20% by volume, D2: 5-20% by volume.
The cermet with 30% by volume and the remaining binder phase is used as a base, and on the surface of the base, titanium, dititanium mononitride, titanium nitride, and TiCxNy (where x<y) are applied.
A single layer consisting of one of these types (excluding the case of titanium), a composite layer consisting of two or more of these types, or one single layer and one composite layer each.
Bitker's hardness consisting of multiple layers combined
A surface-coated cermet member for cutting tools and wear-resistant tools, which is provided with an ultra-hard coating layer having an Hv of 2000 Kg/mm ² or more and a thickness of 1 to 10 μm.