JP2017179474A - Hard metal used for tool for processing nonmetallic material - Google Patents
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- 239000000463 material Substances 0.000 title abstract description 10
- 239000002184 metal Substances 0.000 title abstract description 5
- 229910052751 metal Inorganic materials 0.000 title abstract description 5
- 239000002344 surface layer Substances 0.000 claims abstract description 59
- 150000004767 nitrides Chemical class 0.000 claims abstract description 18
- 239000002245 particle Substances 0.000 claims abstract description 18
- 239000011230 binding agent Substances 0.000 claims abstract description 16
- 239000012535 impurity Substances 0.000 claims abstract description 4
- 150000001247 metal acetylides Chemical class 0.000 claims description 12
- 229910052719 titanium Inorganic materials 0.000 claims description 7
- 229910052750 molybdenum Inorganic materials 0.000 claims description 6
- 229910052758 niobium Inorganic materials 0.000 claims description 6
- 229910052715 tantalum Inorganic materials 0.000 claims description 6
- 229910052735 hafnium Inorganic materials 0.000 claims description 5
- 229910052726 zirconium Inorganic materials 0.000 claims description 5
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 238000005520 cutting process Methods 0.000 abstract description 28
- 239000000956 alloy Substances 0.000 abstract description 8
- 229910045601 alloy Inorganic materials 0.000 abstract description 8
- 229910052804 chromium Inorganic materials 0.000 abstract description 8
- 230000007547 defect Effects 0.000 abstract description 6
- 229910052720 vanadium Inorganic materials 0.000 abstract description 6
- 238000005299 abrasion Methods 0.000 abstract description 2
- 230000006835 compression Effects 0.000 abstract 1
- 238000007906 compression Methods 0.000 abstract 1
- 239000000843 powder Substances 0.000 description 18
- 238000005245 sintering Methods 0.000 description 16
- 238000000034 method Methods 0.000 description 13
- 238000004519 manufacturing process Methods 0.000 description 9
- 239000000203 mixture Substances 0.000 description 9
- 238000005452 bending Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 7
- 239000007769 metal material Substances 0.000 description 7
- 239000011148 porous material Substances 0.000 description 6
- 239000002994 raw material Substances 0.000 description 6
- 239000010953 base metal Substances 0.000 description 5
- 238000005219 brazing Methods 0.000 description 5
- 230000000052 comparative effect Effects 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- 238000005259 measurement Methods 0.000 description 5
- 239000002023 wood Substances 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 4
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- 239000011248 coating agent Substances 0.000 description 3
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- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 229910052786 argon Inorganic materials 0.000 description 2
- 238000005422 blasting Methods 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 238000005260 corrosion Methods 0.000 description 2
- 230000007797 corrosion Effects 0.000 description 2
- 238000002149 energy-dispersive X-ray emission spectroscopy Methods 0.000 description 2
- 230000009422 growth inhibiting effect Effects 0.000 description 2
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- 238000000465 moulding Methods 0.000 description 2
- 229910052755 nonmetal Inorganic materials 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 229910000531 Co alloy Inorganic materials 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 229910003460 diamond Inorganic materials 0.000 description 1
- 239000010432 diamond Substances 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 238000007542 hardness measurement Methods 0.000 description 1
- 239000011121 hardwood Substances 0.000 description 1
- 238000007373 indentation Methods 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
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- 229910052721 tungsten Inorganic materials 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
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Abstract
Description
本発明は、非金属材料を加工するための工具に用いる超硬合金、特に、高硬度木材の切削用工具として用いた場合においても好適である、高硬度、高靱性であって、耐摩耗性に優れた超硬合金に関するものである。 The present invention is a cemented carbide used in a tool for processing a non-metallic material, and particularly suitable for use as a cutting tool for high-hardness wood. It has high hardness, high toughness, and wear resistance. It relates to a cemented carbide having excellent resistance.
従来、非金属系材料を加工するための工具、例えば、高硬度木材の切削工具に用いる超硬合金においては、Ｃｏ含有量が５〜１５ｍａｓｓ％と高い材料では硬度が不足し、木材を加工する際に耐摩耗性が著しく低くなることが判明しており、これに対しＣｏ含有量を低くして３〜５ｍａｓｓ％程度としたところ、焼結性が悪化し、破壊靭性値が低下するという問題が生じていた。 Conventionally, in a cemented carbide used for a tool for processing a non-metallic material, for example, a cutting tool for high-hardness wood, a material having a high Co content of 5 to 15 mass% is insufficient in hardness and processes wood. In this case, it has been found that the wear resistance is remarkably reduced. On the other hand, when the Co content is reduced to about 3 to 5 mass%, the sinterability deteriorates and the fracture toughness value decreases. Has occurred.
そこで、例えば、特許文献１では、ＷＣ基超硬合金において、結合金属相としてのＣｏおよびＮｉの少なくとも一方を１ｗｔ％以上、ＣｏおよびＮｉを合わせて３ｗｔ％以下の割合で含み、さらにＣｒおよびＣｒ炭化物の少なくとも一方をＣｒ量として０．５ｗｔ％以上、１．５ｗｔ％以下、必要に応じ、Ｔｉ、Ｔａ、Ｎｂ、Ｍｏ、Ｖの炭化物、炭窒化物の少なくとも１種を含み、ＷＣの平均粒径を０．２μｍ以上、０．５μｍ以下とし、粒径２μｍ以上のＷＣ粒の含有量を合金の断面組織中の面積比で０．７％以下とし、硬度および抗折力がそれぞれＨＲＡ９４．０以上および２２０ｋｇ／ｍｍ２以上である、木質系硬質材料を加工するための工具に用いられるＷＣ基超硬合金の提案がなされている。
そして、具体的な製造条件としては、焼結温度は、１３５０〜１４５０℃、好ましくは、１４００〜１４５０℃程度とされ、焼結後または焼結と同時にＨＩＰ処理を行うことにより、一層の強度向上が実現できるとされている。
Therefore, for example, in Patent Document 1, in a WC-based cemented carbide, at least one of Co and Ni as a binding metal phase is included in a ratio of 1 wt% or more, and the combined amount of Co and Ni is 3 wt% or less, and Cr and Cr The average grain size of WC including at least one of carbides and carbonitrides of Ti, Ta, Nb, Mo, and V, if necessary, with at least one of carbides as Cr amount of 0.5 wt% or more and 1.5 wt% or less The diameter is 0.2 μm or more and 0.5 μm or less, the content of WC grains having a particle size of 2 μm or more is 0.7% or less in terms of the area ratio in the cross-sectional structure of the alloy, and the hardness and bending strength are HRA 94.0. The proposal of the WC base cemented carbide used for the tool for processing the above-mentioned and 220 kg / mm < 2 > or more of a wooden hard material is made | formed.
As specific production conditions, the sintering temperature is 1350 to 1450 ° C., preferably about 1400 to 1450 ° C., and the strength is further improved by performing HIP treatment after sintering or simultaneously with sintering. Can be realized.
また、特許文献２では、非金属系材料であるガラスの切断用工具に用いられる超硬合金
として、金属相としてのＣｏを０．５〜４ｗｔ％、粒成長抑制剤としてのＶＣ、ＮｂＣ、ＴａＣ、Ｃｒ３Ｃ２、Ｍｏ２Ｃ、ＺｒＣ、ＨｆＣの一種以上を０．１〜３ｗｔ％含有し、残部をＷＣ及び不可避不純物とし、ＷＣの平均粒径が０．２〜１．５μｍであって、Ｈｖが２１００Ｋｇ／ｍｍ２以上である、強度(ＭＯＲ)と耐摩耗性をともに向上したＷＣ基超硬合金の提案がなされている。
そして、具体的な製造方法としては、原料粉末を湿式混合、粉砕、乾燥後、成形体とし、真空下（０．１ｔｏｒｒ）、１３５０℃にて１時間保持後、Ａｒ雰囲気下（１０００ａｔｍ）１２５０℃にて１時間保持し、その後、ＨＩＰ処理による焼結により得られるとされている。
Moreover, in patent document 2, as a cemented carbide used for the tool for cutting glass which is a nonmetallic material, Co as a metal phase is 0.5 to 4 wt%, VC, NbC, and TaC as grain growth inhibitors. , Cr 3 C 2 , Mo 2 C, ZrC, HfC is contained in an amount of 0.1 to 3 wt%, the balance is WC and inevitable impurities, and the average particle size of WC is 0.2 to 1.5 μm. A WC-based cemented carbide having an Hv of 2100 kg / mm 2 or more and improved both strength (MOR) and wear resistance has been proposed.
As a specific manufacturing method, the raw material powder is wet-mixed, pulverized and dried, and then formed into a molded body. After holding in vacuum (0.1 torr) at 1350 ° C. for 1 hour, in an Ar atmosphere (1000 atm) 1250 ° C. For 1 hour, and then obtained by sintering by HIP treatment.
また、特許文献３では、用途が非金属系材料用に限定されたものではないが、切削に用いられる高強度高靱性高耐摩耗性のＷＣ基超硬合金として、Ｃｏを０．１〜１０重量％、Ｃｒ化合物、Ｖ化合物等を含み、ＷＣの平均粒径が１００〜１０００ｎｍであって、高靱性及び高抗折強度を有し、鋼製の超硬チップ等を用途とする断続切削に優れたＷＣ基超硬合金の提案がなされている。
そして、具体的な製造方法としては、原料粉末を湿式混合粉砕、乾燥後、プレス成形体とし、９００℃〜１６００℃の温度範囲にて、アルゴンガスを炉内に導入し、３〜２００気圧の範囲で加圧焼結を行い、焼結の駆動力を増加させることで密度がほぼ１００％の超硬合金を得るというものである。
Further, in Patent Document 3, the use is not limited to non-metallic materials, but Co is 0.1 to 10 as a WC-based cemented carbide of high strength, high toughness and wear resistance used for cutting. For interrupted cutting that uses steel carbide tips and the like, including wt%, Cr compound, V compound, etc., with an average particle size of WC of 100 to 1000 nm, high toughness and high bending strength An excellent WC-based cemented carbide has been proposed.
As a specific manufacturing method, the raw material powder is wet mixed and pulverized, dried, and then formed into a press-molded body, and argon gas is introduced into the furnace at a temperature range of 900 ° C. to 1600 ° C. By performing pressure sintering in the range and increasing the driving force of sintering, a cemented carbide having a density of almost 100% is obtained.
さらに、特許文献４では、熱伝導度の優れた高硬度、高靱性超硬合金の製造方法として、
粒子径が０．５μｍ以下のＷＣ微粒子を用い、Ｃｏ量を０．５〜３ｗｔ％に抑え、さらに、ＶＣ、Ｃｒ３Ｃ２、ＴａＣ、ＨｆＣ、ＺｒＣから選ばれた粉末の少なくとも１種を０．２〜２．０ｗｔ％添加した超硬合金原料粉末を成形し、真空炉にて真空中（１×１０〜１×１０−５Ｔｏｒｒ）で１３００〜１６００℃、１５〜９０分保持し高温焼結を行い、引き続き同一炉にてそのまま温度を常温まで下げることなく、ＡｒまたはＮ２ガスを圧力媒体として炉内ガス圧が、３０〜５００ｋｇ／ｃｍ２となるように導入し、１５〜９０分加圧保持した後、１２００〜１６００℃にて低圧ＨＩＰ処理を行い、その後、常温にすることなく、再度真空中（１×１０〜１×１０−５Ｔｏｒｒ）で１３００〜１６００℃にて、再焼結を行うことが提案されている。
そして、かかる提案により、従来の高圧ＨＩＰ処理では、Ｃｏがポア中に流出することに起因した靱性の低下を解消し、内部に存在するポアを消失させ、更にＨＩＰ後の再焼結により不均一組織を解消し抗折力、硬度の改善を図り、熱伝導度の優れた高硬度、高靱性超硬合金を得るというものである。
Furthermore, in patent document 4, as a manufacturing method of high hardness and high toughness cemented carbide with excellent thermal conductivity,
WC fine particles having a particle diameter of 0.5 μm or less are used, the amount of Co is suppressed to 0.5 to 3 wt%, and at least one powder selected from VC, Cr 3 C 2 , TaC, HfC, and ZrC is 0 Molding cemented carbide raw material powder with 2 to 2.0 wt% added and holding at 1300 to 1600 ° C. for 15 to 90 minutes in a vacuum oven (1 × 10 to 1 × 10 −5 Torr) In the same furnace, without reducing the temperature to room temperature, Ar or N 2 gas was introduced as a pressure medium so that the gas pressure in the furnace would be 30 to 500 kg / cm 2 and 15 to 90 minutes. After maintaining the pressure, low-pressure HIP treatment is performed at 1200 to 1600 ° C., and then again at 1300 to 1600 ° C. in vacuum (1 × 10 to 1 × 10 −5 Torr) again without changing to room temperature. Proposed to sinter It has been.
And by this proposal, in the conventional high-pressure HIP processing, the deterioration of toughness due to Co flowing out into the pores is eliminated, the pores existing inside disappear, and further, non-uniformity by re-sintering after HIP By eliminating the structure and improving the bending strength and hardness, a high hardness and high toughness cemented carbide with excellent thermal conductivity is obtained.
特許文献１及び特許文献２に記載された非金属系材料を加工するための工具に用いる超硬合金においては、ＷＣ粒を細粒化しその平均粒径を規定し、ＣｒやＴｉ、Ｖなどの炭化物、炭窒化物を添加し、高硬度で抗折力に優れた、超硬合金を得ることにより、従来かかる超硬合金において課題となっていた、Ｃｏ含有量によって生じる特性の劣化、特に、低Ｃｏ材料においては抗折力が低下する点を解決した。
しかしながら、強断続切削などの厳しい条件下において用いられる超硬合金においては、更なる耐欠損性が求められるものの、特許文献１や特許文献２に記載された超硬合金では、
耐欠損性が安定して得られないという問題が生じていた。
また、特許文献３では、ＷＣ粒の細粒化と焼結時の駆動力を増加させることにより、高靱性、高抗折強度を有し、断続切削に優れた低Ｃｏ含有のＷＣ基超硬合金の提案がなされているが、例示されている用途は、鋼製の超硬チップ等の切削であり、木材を含む非金属系材料について適用した事例は記載されていない。
また、特許文献４では、ＷＣ粒の細粒化と低圧ＨＩＰ処理に加え、その後の再焼結を行う事で、ポアの消滅と不均一組織の解消により、高靱性、高抗折強度を有する低Ｃｏ含有のＷＣ基超硬合金の提案がなされているものの、断続切削性や木材を含む非金属系材料についての適用については、何ら記載されていない。
そこで、本発明者らは強断続切削においてＷＣが粒内破壊を生じ、それが脱落する事で摩耗が促進されると考え、従来のように、１０ｍａｓｓ％以下の結合相成分の分散性および組織の均一化による靭性向上ではなく、成分の９０ｍａｓｓ％以上を占めるＷＣ自体の靭性を向上することで耐欠損性及び耐摩耗性を飛躍的に向上できるという知見を得た。したがって、本発明は、上記した強断続切削などの厳しい条件下においても、高靭性、高耐摩耗性に優れ、非金属系材料を加工するための工具に用いる超硬合金を提供することを目的としてなされたものである。
In the cemented carbide used for the tool for processing the nonmetallic material described in Patent Document 1 and Patent Document 2, the WC grains are finely divided to define the average particle diameter, and Cr, Ti, V, etc. By adding carbide, carbonitride and obtaining a cemented carbide with high hardness and excellent bending strength, which has been a problem in conventional cemented carbide, deterioration of properties caused by Co content, in particular, Resolved the problem of low bending strength in low Co materials.
However, in the cemented carbide used under severe conditions such as hard interrupted cutting, further fracture resistance is required, but in the cemented carbide described in Patent Document 1 and Patent Document 2,
There has been a problem that the fracture resistance cannot be stably obtained.
Further, in Patent Document 3, by reducing the WC grain size and increasing the driving force during sintering, it has high toughness and high bending strength, and is a low Co-containing WC-based carbide excellent in intermittent cutting. Although the proposal of an alloy is made, the illustrated use is cutting of a carbide tip made of steel or the like, and an example of application to a nonmetallic material including wood is not described.
In Patent Document 4, in addition to WC grain refinement and low-pressure HIP treatment, subsequent re-sintering provides high toughness and high bending strength by eliminating pores and eliminating heterogeneous structures. Although a low Co-containing WC-based cemented carbide has been proposed, there is no description about intermittent machinability and application to non-metallic materials including wood.
Accordingly, the present inventors consider that WC causes intragranular fracture in strong interrupted cutting, and that the wear off is promoted, and as in the past, the dispersibility and structure of the binder phase component of 10 mass% or less. It was found that the fracture resistance and the wear resistance can be remarkably improved by improving the toughness of WC itself, which occupies 90 mass% or more of the components, instead of improving the toughness by homogenizing. Accordingly, an object of the present invention is to provide a cemented carbide that is excellent in high toughness and high wear resistance even under severe conditions such as the above-mentioned hard interrupted cutting, and that is used for a tool for processing a nonmetallic material. It was made as.
本発明は、Ｃｒおよび／またはＣｒの炭化物、窒化物、炭窒化物、並びに、Ｖおよび／またはＶの炭化物、窒化物、炭窒化物の１種または２種以上を含み、結合金属相として、Ｃｏを含む、微粒ＷＣを基とする、ＷＣ基超硬合金において、各成分組成範囲を適正に調整するとともに、微細化されたＷＣ自体に適正な圧縮残留応力を付与することにより、高靭性、高耐摩耗性が備わり、高硬度木材の切削用工具として用いた場合において、長寿命化を達成し得ることを見出したものであり、特に断続切断を繰り返し行う丸鋸切削加工において有用なＷＣ基合金を提供することにより、前記課題を解決したものである。
特に、残留圧縮応力の付与については、種々の製造条件を工夫し、特定の組織構造を見出すことにより達成したものである。
The present invention includes Cr and / or Cr carbide, nitride, carbonitride, and one or more of V and / or V carbide, nitride, carbonitride, In a WC-based cemented carbide based on fine-grained WC containing Co, by appropriately adjusting each component composition range and imparting appropriate compressive residual stress to the refined WC itself, high toughness, It has been found that a long life can be achieved when it is used as a tool for cutting hard wood with high wear resistance, and is particularly useful in a circular saw cutting process in which intermittent cutting is repeated. By providing an alloy, the above problems are solved.
In particular, the application of the residual compressive stress is achieved by devising various manufacturing conditions and finding a specific structure.
本発明は、上記の知見に基づいてなされたものであって、
「（１） 硬質相と結合相とからなり、結合相成分としてのＣｏを１〜５ｍａｓｓ％含み、また、Ｃｒおよび／またはＣｒの炭化物、窒化物、炭窒化物、並びに、Ｖおよび／またはＶの炭化物、窒化物、炭窒化物の１種または２種以上を合計で０．１〜０．７ｍａｓｓ％含み、残部がＷＣと不可避不純物とからなるＷＣ基超硬合金において、
硬度および破壊靭性値がそれぞれ、Ｈｖ２０００以上および４．０ＭＰａ・ｍ１／２以上であり、
ＷＣの平均粒径は０．１〜０．５μｍであり、
また、前記超硬合金は、その表面に表層部を有し、該表層部のＷＣには、１０〜３０ＭＰａの残留圧縮応力が付与されていることを特徴とするＷＣ基超硬合金。
（２） （１）に記載されたＷＣ基超硬合金において、
前記表層部は、垂直断面方向に、最表面から０．１〜１．０μｍまでの領域である第１表層部と、該第１表層部から垂直断面方向に更に１０μｍの領域である第２表層部とからなり、
第１表層部のＣｏ量（質量％）は１５ｍａｓｓ％以上であることを特徴とするＷＣ基超硬合金。
（３） （２）に記載されたＷＣ基超硬合金において、第２表層部における垂直断面方向のＣｏ量（質量％）の最小値に対する最大値の比が、１．５〜２０であることを特徴とするＷＣ基超硬合金。
（４） （２）または（３）のいずれかに記載されたＷＣ基超硬合金において、第２表層部より内部のＨｖ（５０ｋｇｆ）に対する、第１表層部と第２表層部の境界面から第２表層部側０．７μｍ以内の部位におけるＨｖ（５０ｋｇｆ）の比が、０．９〜０．９９であることを特徴とするＷＣ基超硬合金。
（５） （１）〜（４）のいずれかに記載されたＷＣ基超硬合金において、前記表層部の最表面におけるＣｏの面積率が４０％以上であることを特徴とするＷＣ基超硬合金。
（６） （１）〜（５）のいずれかに記載されたＷＣ基超硬合金において、有孔度が超硬合金規格ＣＩＳ００６Ｃ−２００７でＡ０２〜Ａ０６、または、Ｂ０２〜Ｂ０６であることを特徴とするＷＣ基超硬合金。
（７） （１）〜（６）のいずれかに記載されたＷＣ基超硬合金において、結合相成分のＮｉをＣｏの含有量（質量％）の１０ｍａｓｓ％以下で含有することを特徴とするＷＣ基超硬合金。
（８） （１）〜（７）のいずれかに記載されたＷＣ基超硬合金において、Ｔｉ、Ｚｒ、Ｎｂ、Ｍｏ、Ｈｆ及びＴａの炭化物、窒化物、炭窒化物の１種または２種以上を結合相成分の１０ｍａｓｓ％以下で含有させることを特徴とするＷＣ基超硬合金。」
に特徴を有するものである。
The present invention has been made based on the above findings,
“(1) Consisting of a hard phase and a binder phase, containing 1 to 5 mass% of Co as a binder phase component, and Cr and / or Cr carbide, nitride, carbonitride, and V and / or V In a WC-based cemented carbide comprising 0.1 to 0.7 mass% in total of one or more of carbides, nitrides, and carbonitrides of the above, and the balance consisting of WC and inevitable impurities,
The hardness and fracture toughness values are Hv2000 or more and 4.0 MPa · m1 / 2 or more, respectively.
The average particle size of WC is 0.1 to 0.5 μm,
Further, the cemented carbide has a surface layer portion on the surface thereof, and a residual compressive stress of 10 to 30 MPa is applied to the WC of the surface layer portion.
(2) In the WC-based cemented carbide described in (1),
The surface layer portion is a first surface layer portion that is a region from 0.1 to 1.0 μm from the outermost surface in the vertical cross-sectional direction, and a second surface layer that is a region that is further 10 μm from the first surface layer portion in the vertical cross-sectional direction. And consists of
A WC-based cemented carbide characterized in that the Co amount (% by mass) of the first surface layer part is 15 mass% or more.
(3) In the WC-based cemented carbide described in (2), the ratio of the maximum value to the minimum value of the Co amount (% by mass) in the vertical cross-sectional direction in the second surface layer portion is 1.5 to 20. WC-based cemented carbide characterized by
(4) In the WC-based cemented carbide described in either (2) or (3), from the interface between the first surface layer portion and the second surface layer portion with respect to Hv (50 kgf) inside from the second surface layer portion. A WC-based cemented carbide characterized in that the ratio of Hv (50 kgf) at a site within 0.7 μm on the second surface layer side is 0.9 to 0.99.
(5) The WC-based cemented carbide according to any one of (1) to (4), wherein an area ratio of Co on the outermost surface of the surface layer portion is 40% or more. alloy.
(6) The WC-based cemented carbide according to any one of (1) to (5), wherein the porosity is A02 to A06 or B02 to B06 according to cemented carbide standard CIS006C-2007. WC base cemented carbide.
(7) The WC-based cemented carbide according to any one of (1) to (6), wherein Ni as a binder phase component is contained at 10 mass% or less of Co content (mass%). WC base cemented carbide.
(8) In the WC-based cemented carbide described in any one of (1) to (7), one or two of Ti, Zr, Nb, Mo, Hf, and Ta carbide, nitride, and carbonitride A WC-based cemented carbide comprising 10% by mass or less of the binder phase component. "
It has the characteristics.
まず、本発明に係るＷＣ超硬合金について、その最表面部から内部組織に至る構造について概略説明する。
すなわち、本発明に係るＷＣ超硬合金は、図１にも記載されているとおり、表層部と内部とからなり、該表層部は、Ｃｏ量（質量％）が多く、最表面から垂直断面方向に０．１〜１．０μｍの厚みを有する第１表層部と、第１表層部から垂直断面方向に更に１０μｍの厚みを有する第２表層部とからなっている。
以下では、本発明に係る超硬合金の成分組成やその濃度分布、及び、それらを規定する理由等について説明する。
First, the structure from the outermost surface portion to the internal structure of the WC cemented carbide according to the present invention will be schematically described.
That is, the WC cemented carbide according to the present invention is composed of a surface layer portion and an inside as shown in FIG. 1, and the surface layer portion has a large amount of Co (mass%), and is perpendicular to the vertical cross-sectional direction from the outermost surface. The first surface layer portion has a thickness of 0.1 to 1.0 μm, and the second surface layer portion further has a thickness of 10 μm in the vertical cross-sectional direction from the first surface layer portion.
Below, the component composition and concentration distribution of the cemented carbide according to the present invention, the reasons for defining them, and the like will be described.
Ｃｏ：
Ｃｏは結合相を形成するものであり、その含有量が、１ｍａｓｓ％未満では欠損が生じ易くなり、また、５ｍａｓｓ％を超える場合には、耐摩耗性不足となり摩耗が進行することから、Ｃｏの含有量を１〜５ｍａｓｓ％と規定した。（請求項１）
また、超硬合金の表面部には、最表面にＣｏ量（質量％）の高い第１表層部が形成されており、垂直断面方向におけるＣｏの濃度分布と特性の関係についてみてみると、第２表層部において、Ｃｏ量（質量％）の最も少ない部分に対する、Ｃｏ量（質量％）の最も多い部分のＣｏ量（質量％）の比が、１．５未満では、欠損を生じるおそれがあり、また、２０を超えると初期摩耗が増大し、耐摩耗性が低下する可能性があるため、Ｃｏ量（質量％）に組成勾配を設け、第２表層部における最大Ｃｏ量（質量％）に対する最小Ｃｏ量（質量％）の比を１．５〜２０とすることが好ましく、１．５〜５の範囲とすることがより好ましく、１．５〜３の範囲とすることがさらにより好ましい。（請求項２、３）
ダイヤモンド砥石等による切刃部分の研削加工を行う場合、特に非金属加工用に使用される切刃は鋭利なエッジの形成が必要なため、切刃エッジ部にチッピングが発生し易いが、本発明の超硬合金では最表面部とその直下にＣｏ量（質量％）の多い部分が存在するため、研削加工によるチッピングを抑制でき、切削加工時の切刃エッジ部の微小チッピングから生じる初期摩耗を抑制できる。前記Ｃｏ量（質量％）は、１５質量％以上であることが好ましい。（請求項２）
そして、これを、超硬合金の垂直断面方向における硬さ分布（Ｈｖ（５０ｋｇｆ））と特性の関係からみてみると、第２表層部より内部の硬さＨｖ（５０ｋｇｆ）に対する、第１表層部と第２表層部の境界面から第２表層部側０．７μｍ以内の部位におけるＨｖ（５０ｋｇｆ）の比が、０．９９を超えると欠損が生じるおそれがあり、また、０．９未満では、初期摩耗が増大し、耐摩耗性が低下する可能性があるため、第２表層部より内部のＨｖ（５０ｋｇｆ）に対する、第１表層部と第２表層部の境界面から第２表層部側０．７μｍ以内の部位におけるＨｖ（５０ｋｇｆ）の比は、０．９〜０．９９であることが好ましい。（請求項４）
また、台金とのろう付け性の観点から、表面のＣｏ量が多くても面積率が低ければろう付け性は向上せず、表面部におけるＣｏの面積率が４０％未満である場合には、ろう付け性が悪化し、強断続切削などの厳しい条件下において、チップが台金から外れるおそれがあるため、超硬合金の表面部におけるＣｏの面積率は４０％以上とすることが望ましい。そして、そのような面積率を有するＣｏ層の厚みは、０．１μｍ未満では台金とのろう付け性が悪化し、チップが台金から外れるおそれがある一方、１．０μｍを超えると逆に、第１表層部と第２表層部の境界面部分からチップが外れるおそれがある。また、切刃の耐溶着性が悪化するとともに、初期摩耗が増大し、耐摩耗性が低下するおそれがあり、コーティングを施した場合には、コーティング層の剥離が生じ易くなるため、層厚は最表面から０．１〜１．０μｍとすることが好ましい。（請求項２、５）
Co:
Co forms a binder phase, and if its content is less than 1 mass%, defects tend to occur, and if it exceeds 5 mass%, wear resistance becomes insufficient and wear proceeds. The content was defined as 1 to 5 mass%. (Claim 1)
In addition, a first surface layer portion having a high Co content (mass%) is formed on the outermost surface portion of the cemented carbide, and the relationship between the Co concentration distribution and the characteristics in the vertical cross-sectional direction is as follows. 2 If the ratio of the Co amount (mass%) of the portion with the largest amount of Co (mass%) to the portion with the smallest amount of Co (mass%) in the surface layer portion is less than 1.5, there is a risk of defects. In addition, if it exceeds 20, the initial wear may increase and the wear resistance may decrease, so a composition gradient is provided in the Co amount (% by mass), and the maximum Co amount (% by mass) in the second surface layer portion is set. The ratio of the minimum Co amount (% by mass) is preferably 1.5 to 20, more preferably 1.5 to 5, and even more preferably 1.5 to 3. (Claims 2 and 3)
When grinding the cutting edge part with a diamond grindstone or the like, especially the cutting edge used for non-metal processing needs to form a sharp edge. In the cemented carbide alloy, there is a part with a large amount of Co (mass%) immediately below the outermost surface part, so that chipping due to grinding can be suppressed, and initial wear resulting from minute chipping at the edge of the cutting edge during machining is reduced. Can be suppressed. The Co amount (% by mass) is preferably 15% by mass or more. (Claim 2)
When this is seen from the relationship between the hardness distribution (Hv (50 kgf)) in the vertical cross-sectional direction of the cemented carbide and the characteristics, the first surface layer portion with respect to the internal hardness Hv (50 kgf) from the second surface layer portion. If the ratio of Hv (50 kgf) in the portion within 0.7 μm from the boundary surface between the second surface layer portion and the second surface layer portion exceeds 0.99, there is a risk of defects, and if less than 0.9, Since the initial wear may increase and the wear resistance may decrease, the second surface layer side 0 from the boundary surface between the first surface layer portion and the second surface layer portion with respect to Hv (50 kgf) inside from the second surface layer portion 0 The ratio of Hv (50 kgf) at a site within 0.7 μm is preferably 0.9 to 0.99. (Claim 4)
Also, from the viewpoint of brazing with a base metal, if the area ratio is low even if the amount of Co on the surface is large, the brazing performance is not improved, and when the area ratio of Co on the surface is less than 40% Since the brazing property is deteriorated and the chip may be detached from the base metal under severe conditions such as hard interrupted cutting, the area ratio of Co in the surface portion of the cemented carbide is preferably 40% or more. When the thickness of the Co layer having such an area ratio is less than 0.1 μm, the brazing property with the base metal is deteriorated, and the chip may be detached from the base metal. There is a possibility that the chip is detached from the boundary surface portion between the first surface layer portion and the second surface layer portion. In addition, the welding resistance of the cutting edge deteriorates, the initial wear may increase, and the wear resistance may decrease.If coating is applied, the coating layer is likely to peel off, so the layer thickness is It is preferable to set it as 0.1-1.0 micrometer from the outermost surface. (Claims 2 and 5)
Ｎｉ：
ＮｉはＣｏとともに結合相形成元素であり、耐食性が求められる場合には、結合相の強度を考慮し、Ｃｏ量（質量％）に対し１０ｍａｓｓ％以下の範囲で添加することができる。（請求項７）
Ni:
Ni is a binder phase forming element together with Co. When corrosion resistance is required, Ni can be added in a range of 10 mass% or less with respect to the Co amount (% by mass) in consideration of the strength of the binder phase. (Claim 7)
Ｃｒおよび／またはＣｒの炭化物、窒化物、炭窒化物、並びに、Ｖおよび／またはＶの炭化物、窒化物、炭窒化物：
これらの金属及び化合物は、粒成長抑制効果を有し、耐摩耗性を向上させるが、０．１ｍａｓｓ％未満では、粒成長抑制効果が小さく、また、過剰析出が生じなければ、性能の悪化は認められないものの、その１種または２種以上を合計で０．７ｍａｓｓ％を超えて含有する場合には、ＣｒやＶの炭化物等の第３相の過剰析出により強度が低下し、欠損が発生するおそれがあるため、合計で０．１〜０．７ｍａｓｓ％と規定した。また、耐食性の効果を発揮するため、Ｃｒおよび／またはＣｒの炭化物等の添加量は結合相形成成分のＣｏおよび／またはＮｉ量に対して、５ｍａｓｓ％以上とするのが望ましい。（請求項１）
Cr and / or Cr carbides, nitrides, carbonitrides, and V and / or V carbides, nitrides, carbonitrides:
These metals and compounds have a grain growth inhibitory effect and improve wear resistance, but if less than 0.1 mass%, the grain growth inhibitory effect is small, and if excessive precipitation does not occur, the performance deterioration will be Although it is not recognized, when one or more of them are contained in total exceeding 0.7 mass%, the strength decreases due to excessive precipitation of the third phase such as carbides of Cr and V, and defects occur. Therefore, the total amount is defined as 0.1 to 0.7 mass%. Further, in order to exert the effect of corrosion resistance, it is desirable that the addition amount of Cr and / or Cr carbide or the like is 5 mass% or more with respect to the Co and / or Ni amount of the binder phase forming component. (Claim 1)
Ｔｉ、Ｚｒ、Ｎｂ、Ｍｏ、Ｈｆ及びＴａの炭化物、窒化物、炭窒化物：
これらの金属化合物の１種または２種以上を耐熱性成分として、結合相量の１０ｍａｓｓ％以下で含有させることができる。（請求項８）
Ti, Zr, Nb, Mo, Hf and Ta carbides, nitrides, carbonitrides:
One or more of these metal compounds can be contained as a heat-resistant component at 10 mass% or less of the amount of the binder phase. (Claim 8)
ＷＣ：
ＷＣは、硬質相の形成成分であり、結合相、及び、粒成長抑制剤として添加されるＣｒ、Ｖ及びその炭化物、窒化物、炭窒化物、並びに、耐熱性成分として添加されるＴｉ、Ｚｒ、Ｎｂ、Ｍｏ、Ｈｆ及びＴａの炭化物、窒化物、炭窒化物以外の残部を構成するものである。
また、ＷＣ粒としては、平均粒径が０．５μｍを超えるものは、硬度が低下し耐摩耗性が得られないため、平均粒径は０．５μｍ以下とし、他方、平均粒径が、０．１μｍ未満では、硬度は向上するものの、ＷＣ粒の脱落により摩耗が増大するため、ＷＣ粒の平均粒径は、０．１〜０．５μｍと規定した。（請求項１）
WC:
WC is a component for forming a hard phase. Cr, V and its carbide, nitride, carbonitride added as a binder phase, and a grain growth inhibitor, and Ti, Zr added as a heat-resistant component , Nb, Mo, Hf and Ta carbide, nitride, and the remainder other than carbonitride.
In addition, as the WC grains, those having an average particle diameter exceeding 0.5 μm are reduced in hardness and wear resistance cannot be obtained. Therefore, the average particle diameter is 0.5 μm or less, while the average particle diameter is 0 When the thickness is less than 0.1 μm, the hardness is improved, but the wear increases due to the dropping of the WC grains. Therefore, the average grain size of the WC grains is defined as 0.1 to 0.5 μm. (Claim 1)
焼結組織：
本発明に係る焼結組織は、低温での焼結処理、及び 従来より低温でのＨＩＰ処理により得られるものであって、従来低Ｃｏ合金は気孔が生成してしまうため高温で焼結する、もしくは低温で焼結した場合には、その後のＨＩＰ処理を高温高圧とし、強圧下により気孔を消滅させ、強度向上を図っていた。それに対し、本発明では、低温で焼結し、その後のＨＩＰ処理も低温での特殊なＨＩＰ処理とすることにより、表面部だけでなく内部のＷＣ粒に対しても、圧縮残留応力を付与し、ＷＣ粒内の破壊の抑制を図ったため、組織内部にＡ０２〜Ａ０６、かつ、Ｂ０２〜Ｂ０６レベル（超硬工具協会規格ＣＩＳ００６Ｃ−２００７）の気孔が存在した状態であっても、耐欠損性と耐摩耗性の優れた焼結組織としたものである。（請求項６）
付与する残留応力は、１０ＭＰａ未満であるときは、ＷＣ自体の靭性が低く耐欠損性と耐摩耗性の向上効果が少なく、他方、３０ＭＰａを超えると、圧縮応力であってもＷＣ自体に過剰な応力が存在し、欠損を生じるため、ＷＣ粒の残留圧縮応力の範囲は、１０〜３０ＭＰａと規定した。（請求項１）
なお、焼結組織において、ＣｏとＷの複合炭化物（η相）が析出した場合においても、過剰な析出がない限り、特性への影響を及ぼすものではない。
Sintered structure:
The sintered structure according to the present invention is obtained by a sintering process at a low temperature and a HIP process at a lower temperature than in the past, and a conventional low Co alloy is sintered at a high temperature because pores are generated. Alternatively, when sintered at a low temperature, the subsequent HIP treatment was performed at a high temperature and a high pressure, and the pores disappeared under a strong pressure to improve the strength. On the other hand, in the present invention, sintering is performed at a low temperature, and the subsequent HIP process is also performed as a special HIP process at a low temperature, thereby imparting compressive residual stress not only to the surface portion but also to the internal WC grains. Because of the suppression of breakage in the WC grains, even if there are pores at the A02 to A06 and B02 to B06 levels (Carbide Tool Association Standard CIS006C-2007) inside the structure, It has a sintered structure with excellent wear resistance. (Claim 6)
When the residual stress to be applied is less than 10 MPa, the toughness of the WC itself is low and the effect of improving the fracture resistance and wear resistance is small. On the other hand, when the residual stress exceeds 30 MPa, the compressive stress is excessive in the WC itself. Since the stress exists and a defect occurs, the range of the residual compressive stress of the WC grain is defined as 10 to 30 MPa. (Claim 1)
Even in the case where a composite carbide of Co and W (η phase) is precipitated in the sintered structure, it does not affect the properties unless excessive precipitation occurs.
表面被膜の形成：
本発明に係る超硬合金の表面には、表面被膜を形成することができる。
本発明に係る超硬合金の表面にも残留圧縮応力が付与されているため、例えば、皮膜に圧縮応力が付与されるＰＶＤ法では、一層の耐欠損性およびそれに起因する耐摩耗性の向上効果が発揮され、また、皮膜に引張応力が付与されるＣＶＤ法の中でも、コーティング温度の低いＭＴ−ＣＶＤ法では、耐欠損性およびそれに起因する耐摩耗性の向上がみられる。
Surface coating formation:
A surface film can be formed on the surface of the cemented carbide according to the present invention.
Since the residual compressive stress is also applied to the surface of the cemented carbide according to the present invention, for example, in the PVD method in which the compressive stress is applied to the film, the effect of further improving the fracture resistance and the resulting wear resistance is achieved. Among the CVD methods in which tensile stress is applied to the film, the MT-CVD method having a low coating temperature shows improved fracture resistance and wear resistance resulting therefrom.
ＷＣ基超硬合金の作製方法：
以下に、本発明に係るＷＣ基超硬合金の製造方法の一例を示す。なお、本発明の製造方法は、以下の製造方法に限定されるものではない。
まず、所定粒径の粉末を所定の配合組成となるように配合し原料粉末を作製し、
（イ）これを、室温から１３００〜１４００℃まで真空雰囲気中にて０．５〜５℃／分の速度で昇温し、
（ロ）該温度範囲（１３００〜１４００℃）にて、真空雰囲気中で６０〜１８０分保持し、室温までＡｒ雰囲気で冷却する。
（ハ）ついで、室温から所定のＨＩＰ処理温度（１３００〜１４００℃）までを、２〜１０℃／分の速度で昇温し、
（ニ）該ＨＩＰ処理温度（１３００〜１４００℃）にて、０．５〜１０ＭＰａのＡｒ雰囲気中で６０〜２４０分保持し、
（ホ）ついで、上記ＨＩＰ処理温度（１３００〜１４００℃）から１０００℃までを１〜
３℃/ｍｉｎの冷却速度に制御して炉冷する。１０００℃までの炉冷は、Ｃｏ量（質量％）
の高い第１表層部およびＣｏの濃度勾配を有する第２表層部を形成するために必要であり、
以降の冷却は任意の冷却方法で構わない。
上記（イ）〜（ホ）の工程によって、本発明に係るＷＣ基超硬合金を作製することができる。
そして、このようにして作製した本発明に係るＷＣ基超硬合金は、硬質相は平均粒径が０．１〜０．５μｍのＷＣであり、その残留応力が、１０〜３０ＭＰａの圧縮応力を有することにより、高硬度（Ｈｖ２０００以上）、高靭性（４．０ＭＰａ・ｍ１／２以上）に優れた特性を有するものであって、長期間にわたる切断加工において優れた耐欠損性と耐摩耗性を発揮し、切削工具の長寿命化を図ることができる。
なお、残留圧縮応力を付与する手段は、ＨＩＰ処理以外の手段でもよいが、メディア等が直接超硬合金に接触する場合、例えば、ブラスト処理によって圧縮残留応力が付与される場合には、処理された超硬素材のエッジ部に欠けが発生し、非金属切削に必要な鋭利な切刃を形成することはできず、また表面近傍しか効果が得られないため、目的とする耐欠損性と耐摩耗性向上の効果は達成できない。また、研削によっても圧縮残留応力は付与されるが、従来の低Ｃｏ材種では、特に欠けが発生し、ブラスト処理と同様、その効果は表面近傍に留まり、目的とする耐欠損性と耐摩耗性向上の効果は達成できない。
したがって、チッピングが発生しない圧力や砥石の番手を調整し処理することとなるが、それでは目的とするＷＣ自体の靭性向上による耐欠損性および耐摩耗性の向上効果は達成できない。
本発明に係る超硬合金では、ＷＣ自体の靭性の向上のみならず、従来の超硬合金に比べ、表面部に第１表層部を形成させているため、ブラスト処理を施した場合もろう付け強度は問題とはならず、更なる耐欠損性と耐摩耗性の向上が見込まれる。
Preparation method of WC base cemented carbide:
Below, an example of the manufacturing method of the WC base cemented carbide which concerns on this invention is shown. In addition, the manufacturing method of this invention is not limited to the following manufacturing methods.
First, a raw material powder is prepared by blending a powder having a predetermined particle size so as to have a predetermined composition.
(A) The temperature is raised from room temperature to 1300-1400 ° C. in a vacuum atmosphere at a rate of 0.5-5 ° C./min,
(B) Hold in the vacuum range for 60 to 180 minutes in the temperature range (1300 to 1400 ° C.) and cool to room temperature in an Ar atmosphere.
(C) Next, the temperature is raised from room temperature to a predetermined HIP processing temperature (1300 to 1400 ° C.) at a rate of 2 to 10 ° C./min.
(D) At the HIP treatment temperature (1300 to 1400 ° C.), hold in an Ar atmosphere of 0.5 to 10 MPa for 60 to 240 minutes,
(E) Next, from the HIP processing temperature (1300 to 1400 ° C.) to 1000 ° C., 1 to
The furnace is cooled by controlling the cooling rate to 3 ° C./min. The furnace cooling up to 1000 ° C is the amount of Co (mass%)
Is necessary to form a high first surface layer portion and a second surface layer portion having a Co concentration gradient,
Subsequent cooling may be any cooling method.
The WC-based cemented carbide according to the present invention can be produced by the steps (a) to (e).
In the WC-based cemented carbide according to the present invention thus produced, the hard phase is WC having an average particle size of 0.1 to 0.5 μm, and the residual stress is a compressive stress of 10 to 30 MPa. It has excellent properties in high hardness (Hv2000 or higher) and high toughness (4.0 MPa · m1 / 2 or higher), and has excellent fracture resistance and wear resistance in long-term cutting. This makes it possible to extend the life of the cutting tool.
The means for applying the residual compressive stress may be a means other than the HIP process. However, when the medium or the like is in direct contact with the cemented carbide, for example, when the compressive residual stress is applied by the blast process, it is processed. In addition, chipping occurs at the edge of the hard metal material, and it is impossible to form a sharp cutting edge necessary for non-metal cutting. The effect of improving wearability cannot be achieved. Grinding also gives compressive residual stress, but the conventional low Co grades are particularly chipped, and, as with blasting, the effect remains near the surface and the desired fracture resistance and wear resistance. The effect of improving the performance cannot be achieved.
Therefore, the pressure at which no chipping occurs and the count of the grindstone are adjusted and processed. However, the effect of improving the fracture resistance and the wear resistance by improving the toughness of the target WC itself cannot be achieved.
In the cemented carbide according to the present invention, not only the toughness of the WC itself is improved, but also the first surface layer portion is formed on the surface portion compared to the conventional cemented carbide, so even when blasting is performed, brazing Strength is not a problem, and further improvement in fracture resistance and wear resistance is expected.
本発明は、Ｃｒおよび／またはＣｒの炭化物、窒化物、炭窒化物、並びに、Ｖおよび／またはＶの炭化物、窒化物、炭窒化物の１種または２種以上を含み、結合金属相として、Ｃｏを含む、微粒ＷＣを基とする、ＷＣ基超硬合金において、各成分組成範囲を調整するとともに、焼結条件及びＨＩＰ処理条件を調整し、微細化されたＷＣ自体に適正な圧縮残留応力を付与し、高靭性、高耐摩耗性が備わった組織を得ることにより、長寿命化を達成したものであり、特に強断続切断を繰り返し行う非金属系材料の加工用工具において有用なＷＣ基合金を提供するものである。 The present invention includes Cr and / or Cr carbide, nitride, carbonitride, and one or more of V and / or V carbide, nitride, carbonitride, In the WC-based cemented carbide based on fine-grained WC containing Co, the compositional range of each component is adjusted, the sintering conditions and the HIP processing conditions are adjusted, and the appropriate compressive residual stress is applied to the refined WC itself. To achieve a long life by obtaining a structure having high toughness and high wear resistance, and is particularly useful in non-metallic material processing tools that repeatedly perform severe interrupted cutting. An alloy is provided.
つぎに、本発明のＷＣ基超硬合金について、実施例を用いてより具体的に説明する。 Next, the WC-based cemented carbide of the present invention will be described more specifically using examples.
原料粉末として、所定の平均粒径を有する、細粒ＷＣ粉末、Ｃｏ粉末、Ｎｉ粉末、Ｃｒ粉末、Ｖ粉末、及び、Ｃｒ、Ｖ、Ｔｉ、Ｚｒ、Ｎｂ、Ｍｏ、Ｈｆ、Ｔａの化合物粉末（炭化物粉末、窒化物粉末、炭窒化物粉末）を用意し（表１の試料番号１〜１２）、これらの原料粉末を所定組成に配合し、ボールミルにて湿式混合し、乾燥後、１０ｋｇｆ/ｍｍ２の圧力にてプレス成形し圧粉体を製造した。この圧粉体に対し、表２に示される条件にて、焼結及びＨＩＰを行うことによって、表４に示す本発明例超硬合金１〜１２を製造した。 Fine powder WC powder, Co powder, Ni powder, Cr powder, V powder, and Cr, V, Ti, Zr, Nb, Mo, Hf, Ta compound powder having a predetermined average particle size as raw material powder ( Carbide powder, nitride powder, carbonitride powder) (Sample Nos. 1 to 12 in Table 1), these raw material powders are blended into a predetermined composition, wet-mixed in a ball mill, dried, and then 10 kgf / mm A green compact was produced by press molding at a pressure of 2 . By subjecting this green compact to sintering and HIP under the conditions shown in Table 2, the present invention cemented carbides 1 to 12 shown in Table 4 were produced.
また、比較の目的で、表１に示される本発明範囲を外れる配合組成の圧粉体（表１の試料番号１３〜１５）に対して、表２に示される条件にて、焼結及びＨＩＰを行うことにより、表４に示す比較例超硬合金発明１〜３を製造した。 Further, for the purpose of comparison, sintering and HIP were performed under the conditions shown in Table 2 on the green compacts (sample numbers 13 to 15 in Table 1) having a composition outside the scope of the present invention shown in Table 1. The comparative example cemented carbide inventions 1-3 shown in Table 4 were manufactured.
また、同様に比較の目的で、表１に示される本発明範囲の配合組成の試料（表１の試料番号８、１２）について、表３に示される条件（本発明範囲外の条件）にて、焼結及びＨＩＰを行うことにより、表４に示す比較例超硬合金発明４〜５を製造した。 Similarly, for the purpose of comparison, samples having the composition of the present invention range shown in Table 1 (sample numbers 8 and 12 in Table 1) were subjected to the conditions shown in Table 3 (conditions outside the present invention range). Comparative Example Cemented Carbide Inventions 4 to 5 shown in Table 4 were produced by performing sintering and HIP.
次に、上記で得られた本発明例超硬合金１〜１２、及び、比較例超硬合金発明１〜５について、表４に示される各特性値の測定、及び、工具として用いた際の摩耗量を測定したので、以下にて、各測定方法及び測定値の算出方法を示し、得られた結果については、表４に示す。 Next, with respect to the inventive example cemented carbides 1 to 12 and the comparative example cemented carbide inventions 1 to 5 obtained above, measurement of each characteristic value shown in Table 4 and when used as a tool Since the amount of wear was measured, each measurement method and the calculation method of the measured value are shown below, and the obtained results are shown in Table 4.
＜ＷＣの平均粒径、硬度、及び、破壊靱性値＞
それぞれの試料の断面組織を走査型電子顕微鏡（倍率：１００００倍）にて観察するとともに、硬質相を構成するＷＣの平均粒径については、リニアインターセプト法（Ｌｉｎｅｒ Ｉｎｔｅｒｃｅｐｔ）の計算式により算出した。
また、ＷＣ基超硬合金の硬度は、その垂直断面において厚さ方向に均等に、３点にてマイクロビッカース硬度計（Ｈｖ（５０ｋｇｆ））を用いて硬度測定を行い、その平均値として算出した。
さらに、破壊靭性値については、ＪＩＳ Ｒ１６０７の圧子圧入法により測定し、３か所の平均値として算出した。
<Average particle diameter, hardness, and fracture toughness value of WC>
While observing the cross-sectional structure of each sample with a scanning electron microscope (magnification: 10,000 times), the average particle diameter of WC constituting the hard phase was calculated by a calculation formula of a linear intercept method (Liner Intercept).
In addition, the hardness of the WC-based cemented carbide was calculated as an average value by performing hardness measurement using a micro Vickers hardness meter (Hv (50 kgf)) at three points evenly in the thickness direction in the vertical cross section. .
Furthermore, the fracture toughness value was measured by an indentation press method of JIS R1607 and calculated as an average value at three locations.
＜残留応力値＞
残留応力値は、Ｘ線回折法（ＸＲＤ）を用い測定を行った。具体的には、Ｃｕ-Ｋα線を用いて２θ≧１００°に観測されるピーク（ＷＣは１４５°）をＸ線残留応力測定法（２θ−ｓｉｎ2ψ法）によりＷＣにかかる残留応力を算出した。尚、この計算にはヤング率：７００ＧＰａ、ポアソン比：０．１９を用いた。
<Residual stress value>
The residual stress value was measured using an X-ray diffraction method (XRD). Specifically, the residual stress applied to the WC is calculated by the X-ray residual stress measurement method (2θ-sin 2 ψ method) for the peak (WC is 145 °) observed at 2θ ≧ 100 ° using the Cu—Kα ray. did. In this calculation, Young's modulus: 700 GPa and Poisson's ratio: 0.19 were used.
＜Ｃｏ濃度比 （最大値）／（最小値）＞
超硬合金の第２表層部における垂直断面でのＣｏ濃度比、すなわち、Ｃｏ量（質量％）の最小値に対する最大値の比は、第２表層部の全領域について、表面側から０．５μｍ毎にエネルギー分散型Ｘ線分析（ＳＥＭ−ＥＤＳ）を用いてＣｏ量（ｍａｓｓ％）を各２点測定し、その平均値を算出した後、各測定箇所の前記平均値の最小値に対する最大値の比より求めた。
<Co concentration ratio (maximum value) / (minimum value)>
The Co concentration ratio in the vertical cross section in the second surface layer portion of the cemented carbide, that is, the ratio of the maximum value to the minimum value of the Co amount (mass%) is 0.5 μm from the surface side in the entire region of the second surface layer portion. Each time, the amount of Co (mass%) was measured at two points using energy dispersive X-ray analysis (SEM-EDS), and the average value was calculated. Then, the maximum value with respect to the minimum value of the average value at each measurement point It was calculated from the ratio.
＜硬度比 （表層部）／（内部）＞
第２表層部より内部のＨｖ（５０ｋｇｆ）に対する、第１表層部と第２表層部の境界面から第２表層部側０．７μｍ以内の部位におけるＨｖ（５０ｋｇｆ）の硬度比については、それぞれの領域において、各３点にてマイクロビッカース硬度計（Ｈｖ（５０ｋｇｆ））を用いて硬度測定を行い、その平均値を算出し、内部の硬度の平均値に対する、第１表層部と第２表層部の境界面から第２表層部側０．７μｍ以内の部位における硬度の平均値の比により求めた。
<Hardness ratio (surface layer) / (inside)>
About the hardness ratio of Hv (50 kgf) at a portion within 0.7 μm from the boundary surface between the first surface layer portion and the second surface layer portion with respect to Hv (50 kgf) inside from the second surface layer portion, In the region, the hardness is measured using a micro Vickers hardness meter (Hv (50 kgf)) at each of three points, the average value is calculated, and the first surface layer portion and the second surface layer portion with respect to the average value of the internal hardness It was calculated | required by ratio of the average value of the hardness in the site | part within 0.7 micrometer from the 2nd surface layer part side from the boundary surface.
＜最表面部（第１表層部）のＣｏ面積率＞
超硬合金最表面部を、走査型電子顕微鏡（倍率：２００倍）にて撮影し、２００倍視野に対し、Ｃｏが占める面積とその他の部分の面積を画像処理ソフト（ＷｉｎＲＯＯＦ）により算出し、５視野の平均を取って最表面部Ｃｏ面積率とした。（図２を参照。）
＜最表面部（第１表層部）のＣｏ量（質量％）＞
前記走査型電子顕微鏡（倍率：２００倍）による測定により、Ｃｏにて占められているとされた前記超硬合金の最表面部に対し、エネルギー分散型Ｘ線分析（ＳＥＭ−ＥＤＳ）を用いて３点の点分析を行い、その平均を取って最表面部のＣｏ量（質量％）とした。
<Co area ratio of outermost surface portion (first surface layer portion)>
The outermost surface part of the cemented carbide is photographed with a scanning electron microscope (magnification: 200 times), and the area occupied by Co and the area of other parts are calculated by image processing software (WinROOF) with respect to the 200 times field of view, The average of 5 fields of view was taken as the Co area ratio of the outermost surface portion. (See Figure 2)
<Co amount (% by mass) of outermost surface portion (first surface layer portion)>
Using an energy dispersive X-ray analysis (SEM-EDS) on the outermost surface portion of the cemented carbide, which is supposed to be occupied by Co, as measured by the scanning electron microscope (magnification: 200 times). Three-point point analysis was performed, and the average was taken as the Co amount (% by mass) of the outermost surface portion.
＜有孔度の測定＞
超硬合金規格ＣＩＳ００６Ｃ−２００７により測定を行った。
<Measurement of porosity>
Measurement was performed according to cemented carbide standard CIS006C-2007.
＜摩耗量（ｍｍ）測定試験＞
前記の方法により各性値を評価した超硬合金を、Φ３００ｍｍの台金にろう付けし、側面刃先を研磨した後、刃厚３ｍｍ、刃数８５（表４、試料１７種×各５刃）の丸鋸とした。厚さ２０ｍｍのパーチクルボードを被削材とし、回転数４０００ｒｐｍ、送り１０ｍ/ｍｉｎの条件で切断試験を行い、刃先逃げ面の摩耗量を計測した。
<Abrasion amount (mm) measurement test>
The cemented carbide whose properties were evaluated by the above method was brazed to a base metal of Φ300 mm, the side blade edge was polished, the blade thickness was 3 mm, and the number of blades was 85 (Table 4, 17 types of samples × 5 blades each) A circular saw. Using a particle board having a thickness of 20 mm as a work material, a cutting test was performed under the conditions of a rotational speed of 4000 rpm and a feed of 10 m / min, and the amount of wear on the flank face was measured.
表４に示すとおり、本発明例ＷＣ基超硬合金１〜１２は、硬質相を構成するＷＣの平均粒径がいずれも０．１〜０．５μｍと微細組織構造を有し、さらに、硬度及び破壊靭性値について測定を行ったところ、いずれもＨｖ２０００以上の高硬度、破壊靭性値４．０ＭＰａ・ｍ１／２以上の高靭性を有するものであり、切断加工用工具として用いた際も摩耗量が少なく、優れた特性を有するものであった。
これに対し、本発明範囲の成分組成を満足しない、比較例ＷＣ基超硬合金１〜３は、硬度、破壊靱性値を満足することができず、そのため、欠けの発生が見られるものや、欠けが発生しなくとも摩耗量の増大が著しいものであった。
また、本発明範囲の成分組成は満足するものの、一定の製造条件を満たさない、例えば、焼結温度、或いは、ＨＩＰ温度が１４００℃を大きく超えるものについては、比較例ＷＣ基超硬合金４、５の結果にみられるように、残留応力値が低く、チッピングが生じたり、また、硬度が低く、摩耗量が多くなるなど、満足の得られるものではなかった。
As shown in Table 4, the present invention examples WC-based cemented carbides 1 to 12 have a fine structure with an average particle diameter of WC constituting the hard phase of 0.1 to 0.5 μm, and further, hardness And fracture toughness values were measured, both of which have a high hardness of Hv2000 or higher and a fracture toughness value of 4.0 MPa · m1 / 2 or higher, and wear when used as a cutting tool. The amount was small and had excellent characteristics.
On the other hand, Comparative Example WC-based cemented carbides 1 to 3 that do not satisfy the component composition of the present invention range cannot satisfy the hardness and fracture toughness values, and therefore, occurrence of chipping is observed, Even if no chipping occurred, the amount of wear was remarkably increased.
The composition of the present invention is satisfactory, but does not satisfy certain manufacturing conditions. For example, the sintering temperature or the HIP temperature greatly exceeds 1400 ° C., Comparative Example WC-based cemented carbide 4, As can be seen from the result of No. 5, the residual stress value was low, chipping occurred, the hardness was low, and the wear amount was not satisfactory.
本発明に係るＷＣ基超硬合金は、強断続切削などの厳しい条件下においても、高靭性、高耐摩耗性に優れるため、非金属系材料の加工用工具を含む切断加工用工具として用いることができ、極めて有用である。
Since the WC-based cemented carbide according to the present invention is excellent in high toughness and high wear resistance even under severe conditions such as hard interrupted cutting, it should be used as a cutting tool including a tool for processing non-metallic materials. It is extremely useful.
Claims (8)
硬度および破壊靭性値がそれぞれ、Ｈｖ２０００以上および４．０ＭＰａ・ｍ１／２以上であり、
ＷＣの平均粒径は０．１〜０．５μｍであり、
また、前記超硬合金は、その表面に表層部を有し、該表層部のＷＣには、１０〜３０ＭＰａの残留圧縮応力が付与されていることを特徴とするＷＣ基超硬合金。 It consists of a hard phase and a binder phase, contains 1 to 5 mass% of Co as a binder phase component, and also contains Cr and / or Cr carbide, nitride, carbonitride, and V and / or V carbide, nitride In a WC-based cemented carbide comprising one or two or more of carbonitrides and carbonitrides in a total of 0.1 to 0.7 mass%, and the balance consisting of WC and inevitable impurities,
The hardness and fracture toughness values are Hv2000 or more and 4.0 MPa · m1 / 2 or more, respectively.
The average particle size of WC is 0.1 to 0.5 μm,
Further, the cemented carbide has a surface layer portion on the surface thereof, and a residual compressive stress of 10 to 30 MPa is applied to the WC of the surface layer portion.
前記表層部は、垂直断面方向に、最表面から０．１〜１．０μｍまでの領域である第１表層部と、該第１表層部から垂直断面方向に更に１０μｍの領域である第２表層部とからなり、
第１表層部のＣｏ量（質量％）は１５ｍａｓｓ％以上であることを特徴とするＷＣ基超硬合金。 In the WC base cemented carbide according to claim 1,
The surface layer portion is a first surface layer portion that is a region from 0.1 to 1.0 μm from the outermost surface in the vertical cross-sectional direction, and a second surface layer that is a region that is further 10 μm from the first surface layer portion in the vertical cross-sectional direction. And consists of
A WC-based cemented carbide characterized in that the Co amount (% by mass) of the first surface layer part is 15 mass% or more.
第２表層部における垂直断面方向のＣｏ量（質量％）の最小値に対する最大値の比が、１．５〜２０であることを特徴とするＷＣ基超硬合金。 In the WC base cemented carbide according to claim 2,
A WC-based cemented carbide characterized in that the ratio of the maximum value to the minimum value of Co amount (% by mass) in the vertical cross-sectional direction in the second surface layer portion is 1.5 to 20.
第２表層部より内部のＨｖ（５０ｋｇｆ）に対する、第１表層部と第２表層部の境界面から第２表層部側０．７μｍ以内の部位におけるＨｖ（５０ｋｇｆ）の比が、０．９〜０．９９であることを特徴とするＷＣ基超硬合金。 In the WC base cemented carbide according to any one of claims 2 and 3,
The ratio of Hv (50 kgf) at a portion within 0.7 μm from the boundary surface between the first surface layer portion and the second surface layer portion to Hv (50 kgf) inside from the second surface layer portion is 0.9 to A WC-based cemented carbide characterized by being 0.99.
前記表層部の最表面におけるＣｏの面積率が４０％以上であることを特徴とするＷＣ基超硬合金。 In the WC base cemented carbide according to any one of claims 1 to 4,
WC-based cemented carbide characterized in that the area ratio of Co on the outermost surface of the surface layer portion is 40% or more.
有孔度が超硬合金規格ＣＩＳ００６Ｃ−２００７でＡ０２〜Ａ０６、または、Ｂ０２〜Ｂ０６であることを特徴とするＷＣ基超硬合金。 In the WC-based cemented carbide according to any one of claims 1 to 5,
A WC-based cemented carbide having a porosity of A02 to A06 or B02 to B06 according to cemented carbide standard CIS006C-2007.
結合相成分のＮｉをＣｏの含有量（質量％）の１０ｍａｓｓ％以下で含有することを特徴とするＷＣ基超硬合金。 In the WC base cemented carbide according to any one of claims 1 to 6,
A WC-based cemented carbide comprising Ni as a binder phase component at 10 mass% or less of the Co content (% by mass).
Ｔｉ、Ｚｒ、Ｎｂ、Ｍｏ、Ｈｆ及びＴａの炭化物、窒化物、炭窒化物の１種または２種以上を結合相成分の１０ｍａｓｓ％以下で含有させることを特徴とするＷＣ基超硬合金。 In the WC base cemented carbide according to any one of claims 1 to 7,
A WC-based cemented carbide comprising one or more of Ti, Zr, Nb, Mo, Hf and Ta carbides, nitrides, and carbonitrides in an amount of 10 mass% or less of the binder phase component.
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| JP2021107095A (en) * | 2019-12-27 | 2021-07-29 | 株式会社Moldino | Coated cutting tool |
| JP2023503854A (en) * | 2019-11-22 | 2023-02-01 | セラティチット ルクセンブルグ エス．アー．エール．エル | Tungsten carbide hard metal material |
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| JPH07179978A (en) * | 1993-12-22 | 1995-07-18 | Sumitomo Electric Ind Ltd | Nitrogen-containing sintered hard alloy |
| JPH08218145A (en) * | 1995-02-09 | 1996-08-27 | Sumitomo Electric Ind Ltd | Cemented carbide for tool for working woody hard material |
| JP2015145533A (en) * | 2015-02-04 | 2015-08-13 | 住友電気工業株式会社 | Cemented carbide and working tool |
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| JPH07179978A (en) * | 1993-12-22 | 1995-07-18 | Sumitomo Electric Ind Ltd | Nitrogen-containing sintered hard alloy |
| JPH08218145A (en) * | 1995-02-09 | 1996-08-27 | Sumitomo Electric Ind Ltd | Cemented carbide for tool for working woody hard material |
| JP2015145533A (en) * | 2015-02-04 | 2015-08-13 | 住友電気工業株式会社 | Cemented carbide and working tool |
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| JP2023503854A (en) * | 2019-11-22 | 2023-02-01 | セラティチット ルクセンブルグ エス．アー．エール．エル | Tungsten carbide hard metal material |
| JP7385751B2 (en) | 2019-11-22 | 2023-11-22 | セラティチット ルクセンブルグ エス．アー．エール．エル | Tungsten carbide hard metal material |
| JP2021107095A (en) * | 2019-12-27 | 2021-07-29 | 株式会社Moldino | Coated cutting tool |
| JP7410383B2 (en) | 2019-12-27 | 2024-01-10 | 株式会社Moldino | coated cutting tools |
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