JP3511740B2 - Method for producing high toughness cemented carbide and composite cemented carbide roll - Google Patents
Method for producing high toughness cemented carbide and composite cemented carbide rollInfo
- Publication number
- JP3511740B2 JP3511740B2 JP17066595A JP17066595A JP3511740B2 JP 3511740 B2 JP3511740 B2 JP 3511740B2 JP 17066595 A JP17066595 A JP 17066595A JP 17066595 A JP17066595 A JP 17066595A JP 3511740 B2 JP3511740 B2 JP 3511740B2
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- powder
- cemented carbide
- container
- high toughness
- roll
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Description
【０００１】[0001]
【産業上の利用分野】本発明は、破壊靭性及び耐酸化性
に優れた高靭性超硬合金に関し、特に、温間又は熱間加
工用工具に適した超硬合金の製造方法及びこの超硬合金
を外層材として用いた複合超硬合金ロールに関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high toughness cemented carbide having excellent fracture toughness and oxidation resistance, and particularly to a method for producing a cemented carbide suitable for a tool for warm or hot working, and the cemented carbide. The present invention relates to a composite cemented carbide roll using an alloy as an outer layer material.
【０００２】[0002]
【従来の技術】温間又は熱間加工用工具に用いる超硬合
金として、WCを基とし鉄族金属を結合材としたWC-Co系
合金が、従来から用いられている。温間又は熱間加工用
工具の中でも、800〜1000℃の高温の圧延材と当接する
圧延ロールのように、耐熱衝撃性及び耐摩耗性が要求さ
れる用途には、例えば、特開昭49- 66510号公報記載の
ようなWC-Co-Ni系合金が用いられている。また、特開昭
50-27708号公報記載のように、さらに破壊靭性及び耐食
性に優れるWC-Co-Ni-Cr系合金等もある。また、強度と
靱性に優れた合金鋼を内層材とし、耐摩耗性に優れた超
硬合金を外層材とする複合超硬合金ロールの製造方法と
しては、ろう付け法、鋳包み法、熱間等方圧加圧（以下
ＨＩＰと称する場合あり）法による拡散接合が用いられ
る。2. Description of the Related Art As a cemented carbide used in a tool for warm or hot working, a WC-Co based alloy containing WC as a base and an iron group metal as a binder has been conventionally used. Among the tools for warm or hot working, for applications in which thermal shock resistance and wear resistance are required, such as a rolling roll that comes into contact with a rolled material at a high temperature of 800 to 1000 ° C., for example, JP-A-49 A WC-Co-Ni alloy as described in Japanese Patent No. 66510 is used. In addition,
As described in Japanese Patent Laid-Open No. 50-27708, there are WC-Co-Ni-Cr alloys and the like which are further excellent in fracture toughness and corrosion resistance. Further, as a method for producing a composite cemented carbide roll having an alloy steel having excellent strength and toughness as an inner layer material and a cemented carbide having excellent wear resistance as an outer layer material, a brazing method, a cast-in method, a hot work method Diffusion bonding by an isotropic pressure (hereinafter sometimes referred to as HIP) method is used.
【０００３】[0003]
【発明が解決しようとする課題】従来の超硬合金は、耐
摩耗性に満足するものの、高温の圧延材と当接する圧延
ロールのように、高荷重で、且つ冷却水により急冷され
るという急激な熱サイクル変化が加わる厳しい使用条件
では、破壊靭性、耐酸化性の点で未だ十分満足されてい
ない。更に、従来の複合超硬合金ロールの場合、ろう付
け法では圧延使用中の強度に耐えうる接着強度を確保で
きない、鋳鋼材の鋳包み法ではその製法の限界により高
い耐摩耗性が得られない、また、鋼材に超硬合金をＨＩ
Ｐ拡散接合する複合化も試みられているが、外内層の収
縮差により２次破壊を発生するという問題があり、硬質
粒子を多量に添加できない。従って、本発明はこのよう
な問題を解決し、圧延ロール等に必要な耐摩耗性を有す
ると共に、破壊靭性及び耐酸化性に優れた高靭性超硬合
金の製造方法及びこの超硬合金を外層材として用いた複
合超硬合金ロールの提供を目的とする。Although conventional cemented carbides are satisfactory in wear resistance, they have a high load like a rolling roll that comes into contact with a high-temperature rolling material and are rapidly cooled by cooling water. Under severe operating conditions in which various thermal cycle changes occur, fracture toughness and oxidation resistance are not yet fully satisfied. Furthermore, in the case of the conventional composite cemented carbide roll, the brazing method cannot secure an adhesive strength that can endure the strength during rolling use, and the cast-in method of cast steel material cannot obtain high wear resistance due to its manufacturing limit. , HI made of cemented carbide for steel
A composite method of P diffusion bonding has been attempted, but there is a problem that secondary fracture occurs due to the difference in shrinkage of the outer and inner layers, and a large amount of hard particles cannot be added. Therefore, the present invention solves such a problem, and has a wear resistance required for a rolling roll and the like, a method for producing a high toughness cemented carbide having excellent fracture toughness and oxidation resistance, and the cemented carbide as an outer layer. The purpose is to provide a composite cemented carbide roll used as a material.
【０００４】[0004]
【課題を解決するための手段】本発明者らは、温間又は
熱間加工用工具に用いるのに適した合金を得るために、
特に結合相とのぬれ性に優れ、且つ結合相との界面強度
が大きく、さらに硬さが他の炭化物大で、WCを硬質相と
して含有するWC基超硬合金に着目した。この超硬合金の
結合相に、さらに強度、耐酸化性を付与すべく研究を行
った結果、WC基超硬合金が有する優れた耐摩耗性及び破
壊靭性を保持した状態で、極めて優れた機械的強度を有
し、さらに耐熱衝撃性、耐酸化性に優れ、温間又は熱間
加工用工具に要求される特性を具備する超硬合金の製造
方法をみつけた。In order to obtain an alloy suitable for use in warm or hot working tools, we have:
In particular, we focused on a WC-based cemented carbide that has excellent wettability with the binder phase, has a large interfacial strength with the binder phase, has a large hardness of other carbides, and contains WC as a hard phase. As a result of conducting research to give strength and oxidation resistance to the binder phase of this cemented carbide, as a result, it is possible to obtain extremely excellent mechanical properties while maintaining the excellent wear resistance and fracture toughness of WC-based cemented carbide. We have found a method for producing a cemented carbide that has a high mechanical strength, is excellent in thermal shock resistance and oxidation resistance, and has the characteristics required for a warm or hot working tool.
【０００５】即ち、本発明の高靭性超硬合金の製造方法
は、WCの硬質相とCo及びNiの結合相とからなる超硬合金
の原料粉末に、Cr-Si化合物粉末を配合することを基本
とし、体積比でCo粉末 15〜25％、Ni粉末 5〜15％、Cr-
Si化合物粉末 0.5〜10％、WC粉末 50〜79.5％を含む混
合粉末を焼結することを特徴とする。That is, in the method for producing a high toughness cemented carbide of the present invention, a Cr-Si compound powder is blended with a raw material powder of a cemented carbide composed of a hard phase of WC and a binding phase of Co and Ni. Basically, by volume ratio, Co powder 15-25%, Ni powder 5-15%, Cr-
It is characterized in that a mixed powder containing 0.5 to 10% of Si compound powder and 50 to 79.5% of WC powder is sintered.
【０００６】このときのCr-Si化合物は、Cr3Si、CrSi、
CrSi2の中の何れか一種、又は二種以上の混合物であ
る。また、WC粉末の平均粒子径は1.0〜10μmが好まし
い。At this time, the Cr-Si compounds are Cr 3 Si, CrSi,
It is any one kind of CrSi 2 or a mixture of two or more kinds. The average particle size of the WC powder is preferably 1.0 to 10 μm.
【０００７】焼結は、前記混合粉末を加圧成形の後、温
度 1350〜1450℃の減圧雰囲気中で行う。また、前記混
合粉末を熱間等方圧加圧処理用の容器に充填の後、容器
の内部を脱気処理して密封し、容器に充填密封された前
記混合粉末を温度 1200〜1400℃、圧力 150MPa以下の雰
囲気条件でＨＩＰ処理して焼結することもできる。Sintering is performed in a reduced pressure atmosphere at a temperature of 1350 to 1450 ° C. after the mixed powder is pressure-molded. Further, after filling the mixed powder in a container for hot isostatic pressing, the inside of the container is deaerated and sealed, and the mixed powder filled and sealed in the container is heated at a temperature of 1200 to 1400 ° C. It is also possible to perform HIP treatment and sinter under an atmospheric condition of a pressure of 150 MPa or less.
【０００８】また、本発明の複合超硬合金ロールは、合
金鋼からなる内層材の外周に、外層材が体積比でCo粉末
15〜25％、Ni粉末 5〜15％、Cr-Si化合物粉末 0.5〜10
％、WC粉末 50〜79.5％を含む混合粉末が焼結されたこ
とを特徴とする。In the composite cemented carbide roll of the present invention, the outer layer material is a Co powder in a volume ratio on the outer periphery of the inner layer material made of alloy steel.
15-25%, Ni powder 5-15%, Cr-Si compound powder 0.5-10
%, WC powder 50 to 79.5% mixed powder was sintered.
【０００９】さらに、本発明の複合超硬合金ロールは、
合金鋼からなる内層材の外周部と熱間等方圧加圧処理用
の容器の内面との間に形成した空間部に、外層材として
体積比でCo粉末 15〜25％、Ni粉末 5〜15％、Cr-Si化合
物粉末 0.5〜10％、WC粉末 50〜79.5％を含む混合粉末
を充填の後、容器の内部を脱気処理して密封し、容器に
充填密封された前記混合粉末を温度 1200〜1400℃、圧
力 150MPa以下の雰囲気条件で熱間等方圧加圧処理によ
り焼結したことを特徴とする。本発明の複合超硬合金ロ
ールにおいて、Cr-Si化合物は、Cr3Si、CrSi、CrSi2の
中の何れか一種、又は二種以上の混合物であり、WC粉末
の平均粒子径は1.0〜10μmが好ましい。Further, the composite cemented carbide roll of the present invention is
In the space formed between the outer periphery of the inner layer material made of alloy steel and the inner surface of the container for hot isostatic pressing, Co powder 15 to 25% by volume and Ni powder 5 to 5 as the outer layer material. After filling a mixed powder containing 15%, Cr-Si compound powder 0.5 to 10%, and WC powder 50 to 79.5%, the inside of the container is deaerated and sealed, and the container is filled and sealed. It is characterized by being sintered by hot isostatic pressing under an atmosphere condition of a temperature of 1200 to 1400 ° C and a pressure of 150 MPa or less. In the composite cemented carbide roll of the present invention, the Cr-Si compound is any one of Cr 3 Si, CrSi, CrSi 2 , or a mixture of two or more thereof, and the average particle diameter of the WC powder is 1.0 to 10 μm. Is preferred.
【００１０】[0010]
【作用】このようにして、本発明の製造方法により得ら
れる高靭性超硬合金は、焼結過程で結合相に固溶したCr
-Si化合物が、冷却過程でWC相と結合相との界面に析出
することにより２相間の界面エネルギ−を上昇させ、負
荷により発生するクラックの進展を抑制すること、機械
的強度を向上させること、密着性のあるCr2O3とSiO2粒
子を形成して多孔質酸化層の成長を抑制すること等によ
り高靭性、且つ高耐酸化性を示すと考えられる。In this way, the high toughness cemented carbide obtained by the manufacturing method of the present invention is made of Cr dissolved in the binder phase during the sintering process.
-Si compounds increase the interfacial energy between two phases by precipitating at the interface between the WC phase and the binder phase during the cooling process, suppressing the progress of cracks generated by the load, and improving the mechanical strength. It is considered that high toughness and high oxidation resistance are exhibited by forming Cr 2 O 3 and SiO 2 particles having adhesiveness to suppress the growth of the porous oxide layer.
【００１１】本発明における混合粉末の各配合組成の限
定理由は次の通りである。
(a) Co粉末 15〜25体積％
CoはNiと共に固溶体の結合相を形成し、本発明法による
合金を強化すると共に、耐酸化性を向上する。Co粉末の
配合量は、15体積％未満では効果が十分に得られず、25
体積％を越えると極端に硬さが低下して耐摩耗性が劣化
するので、15〜25体積％とする。The reasons for limiting the blending composition of the mixed powder in the present invention are as follows. (a) Co powder 15 to 25 volume% Co forms a solid solution binder phase together with Ni, strengthens the alloy according to the method of the present invention, and improves the oxidation resistance. If the content of Co powder is less than 15% by volume, the effect cannot be sufficiently obtained.
If the content exceeds 15% by volume, the hardness is extremely lowered and the wear resistance is deteriorated, so the content is set to 15 to 25% by volume.
【００１２】(b) Ni粉末 5〜15体積％
NiはCoと共に固溶体の結合相を形成し、同様に本発明法
による合金の強度及び耐酸化性を向上させる効果をもた
らす。Ni粉末の配合量は、5体積％未満では効果が得ら
れず、15体積％を越えると硬さが低下するので、5〜15
体積％とする。(B) Ni powder 5 to 15% by volume Ni forms a binder phase of a solid solution together with Co and similarly brings about an effect of improving strength and oxidation resistance of the alloy according to the method of the present invention. If the content of Ni powder is less than 5% by volume, the effect cannot be obtained, and if it exceeds 15% by volume, the hardness decreases.
Volume%
【００１３】(c) Cr-Si化合物粉末 0.5〜10体積％
前述のように、Cr-Si化合物粉末の配合は本発明の最も
特徴とするところである。ここで用いるCr-Si化合物はC
r3Si、CrSi、CrSi2等である。これらのCr-Si化合物は何
れも同様の作用効果を示し、本発明法による合金の破壊
靭性及び耐酸化性を向上させる。これらCr-Si化合物の
中の１種又は２種以上の配合量が、0.5体積％未満では
効果が十分に得られず、10体積％を越えるとM6C相(Co3W
3C)を析出して靭性が低下するので、0.5〜10体積％とす
る。(C) Cr-Si compound powder 0.5 to 10% by volume As described above, the compounding of the Cr-Si compound powder is the most feature of the present invention. The Cr-Si compound used here is C
r 3 Si, CrSi, CrSi 2, etc. All of these Cr-Si compounds have similar effects and improve the fracture toughness and oxidation resistance of the alloy according to the method of the present invention. If the content of one or more of these Cr-Si compounds is less than 0.5% by volume, the effect cannot be sufficiently obtained, and if it exceeds 10% by volume, the M 6 C phase (Co 3 W
3 C) precipitates and the toughness decreases, so the content is made 0.5 to 10% by volume.
【００１４】(d) WC粉末 50〜79.5体積％
WC粉末は、本発明法による合金の基質となるもので、多
いほど耐摩耗性向上に寄与する。WC粉末の配合量が、50
体積％未満では耐摩耗性が不足し、さらに耐肌荒れ性が
不足する。逆に過剰になると破壊靭性が低下する。本発
明法による合金においては、強度、破壊靭性、耐酸化性
等を確保する上で必要な上述の他の組成物の配合量とも
関連して、50〜79.5体積％とする。(D) WC powder 50 to 79.5% by volume WC powder is a substrate of the alloy according to the method of the present invention, and the larger the amount, the more it contributes to the improvement of wear resistance. WC powder content is 50
If it is less than volume%, the abrasion resistance is insufficient, and further the rough skin resistance is insufficient. On the contrary, if it becomes excessive, the fracture toughness decreases. In the alloy according to the method of the present invention, it is 50 to 79.5% by volume in relation to the blending amount of the above-mentioned other composition necessary for ensuring strength, fracture toughness, oxidation resistance and the like.
【００１５】(e) WC粉末平均粒子径 1.0〜10μm
WC粉末の平均粒子径は、1.0μm未満にすると本発明法に
よる合金の硬さを向上させるが、破壊靭性を著しく低下
させる。また、10μmを越えると抗折強度の低下をもた
らす。高靭性、且つ高強度、さらに優れた耐摩耗性を付
与するため、その平均粒子径は1.0〜10μmとする。(E) WC powder average particle diameter 1.0 to 10 μm When the average particle diameter of WC powder is less than 1.0 μm, the hardness of the alloy according to the method of the present invention is improved, but the fracture toughness is remarkably lowered. If it exceeds 10 μm, the bending strength is lowered. In order to impart high toughness, high strength, and excellent wear resistance, the average particle size is set to 1.0 to 10 μm.
【００１６】次に、上記配合による混合粉末は加圧して
所定の形状に成形する。その後、温度 1350〜1450℃の
減圧雰囲気中で焼結することにより、本発明が目的とす
る合金が得られる。焼結温度が1350℃未満では、結合金
属の溶融が不十分となり焼結が起こり難く、合金中に多
くの空孔が残存し、所期の高靭性、高強度を有する合金
が得られなくなる。焼結温度が1450℃を越えると、結合
相中へ溶解するW量が増大し、それに伴い結合金属の融
点温度が低下する。このため、焼結過程における結合金
属の流動性が大きくなり、焼結体に変形が生じる。さら
に、過昇温のためWC粒子が著しく成長し、抗折強度を低
下させる。次に、圧力は6Pa以下となるように減圧する
のが好ましい。圧力が6Paを越えると脱気が不十分とな
り、不可避的に混入する不純物ガスの影響により焼結後
の合金の表面近傍が脱炭され、耐摩耗性を低下させる。Next, the mixed powder having the above composition is pressed to be molded into a predetermined shape. Then, by sintering in a reduced pressure atmosphere at a temperature of 1350 to 1450 ° C., the alloy intended by the present invention can be obtained. If the sintering temperature is less than 1350 ° C., the melting of the binding metal is insufficient and sintering is difficult to occur, many pores remain in the alloy, and the alloy having the desired high toughness and high strength cannot be obtained. When the sintering temperature exceeds 1450 ° C, the amount of W dissolved in the binder phase increases, and the melting temperature of the binder metal decreases accordingly. For this reason, the fluidity of the binding metal in the sintering process increases, and the sintered body is deformed. Further, due to the excessive temperature rise, the WC particles grow remarkably and the bending strength is lowered. Next, it is preferable to reduce the pressure to 6 Pa or less. If the pressure exceeds 6 Pa, deaeration becomes insufficient, and the vicinity of the surface of the alloy after sintering is unavoidably decarburized due to the influence of the impurity gas mixed in, and wear resistance is reduced.
【００１７】また、上記配合による混合粉末はＨＩＰ処
理用の容器に充填の後、容器の内部を脱気処理して密封
し、容器に充填密封された前記混合粉末を温度 1200〜1
400℃、圧力 150MPa以下の雰囲気条件でＨＩＰ処理して
焼結することによっても、さらに緻密質の本発明目的の
合金が得られる。このとき、ＨＩＰ処理用の容器内部の
脱気処理は、最終的に到達する圧力を0.2Pa以下の状態
にするのが好ましい。この圧力が0.2Paを越えるとき
は、脱気が不十分なため、混入している不純物ガスの影
響により合金が脱炭され、耐摩耗性及び靱性が低下す
る。さらに、混合粉末表面に吸着している酸素ガスは、
ＨＩＰ処理過程で、合金中のCr等の元素と反応して酸化
物を生成するので、合金の破壊靭性及び抗折強度が低下
する。次に、ＨＩＰ処理温度が1200℃未満では、結合金
属の十分な溶融流動が起こらないので、焼結が起こり難
くなり、所期の高靭性、高強度を有する緻密質の合金が
得られなくなる。ＨＩＰ処理温度が1400℃を越えると、
WC粒子が急激に成長するので、抗折強度が低下する。Ｈ
ＩＰ処理のときに加える圧力は150MPa以下で行うのが好
ましい。150MPaを越えても、緻密質で高靭性、高強度の
合金が得られるが、その効果は飽和する。なお、このＨ
ＩＰ処理法の適用は、本発明法による合金を鋼等の母材
へ拡散接合して複合部材を製作するときに、特に有効で
ある。The mixed powder having the above composition is filled in a container for HIP treatment, the inside of the container is deaerated and sealed, and the mixed powder filled in the container is sealed at a temperature of 1200 to 1
The HIP treatment and sintering under an atmospheric condition of 400 ° C. and a pressure of 150 MPa or less can also provide a denser alloy for the purpose of the present invention. At this time, in the degassing process inside the HIP processing container, it is preferable that the finally reached pressure is set to 0.2 Pa or less. When the pressure exceeds 0.2 Pa, deaeration is insufficient, and the alloy gas is decarburized due to the influence of the mixed impurity gas, and the wear resistance and toughness deteriorate. Furthermore, the oxygen gas adsorbed on the surface of the mixed powder is
During the HIP process, it reacts with elements such as Cr in the alloy to form an oxide, which reduces the fracture toughness and transverse strength of the alloy. Next, when the HIP treatment temperature is less than 1200 ° C., sufficient melting and flow of the bonding metal does not occur, so that it becomes difficult for sintering to occur, and a desired dense alloy having high toughness and high strength cannot be obtained. When the HIP processing temperature exceeds 1400 ° C,
Since the WC particles grow rapidly, the bending strength decreases. H
The pressure applied during IP treatment is preferably 150 MPa or less. Even if it exceeds 150 MPa, a dense alloy with high toughness and high strength can be obtained, but the effect is saturated. In addition, this H
The application of the IP treatment method is particularly effective when the alloy according to the present invention is diffusion bonded to a base material such as steel to manufacture a composite member.
【００１８】[0018]
実施例１
原料粉末として、各々平均粒度 2.6μmのWC粉末、2.6μ
mのCo粉末、2.59μmのNi粉末、2.5μmのCr粉末、2.6μm
のSi粉末、1.4μmのCr2N粉末、2.42μmのCr3C2粉末、1.
85μmのCrSi粉末、1.25μmのCr3Si粉末、1.11μmのCrSi
2粉末を準備した。これらの原料粉末を表１に示す組成
配合となるようにした20種の混合粉末（番号 1〜20）を
調製した。表１において、混合粉末 1〜13は、本発明法
によるもので、Cr成分とSi成分をCr-Si化合物により配
合したものである。混合粉末 14〜20は、比較用とし
て、Cr成分とSi成分をそれぞれ単独又はCr-Si化合物以
外の化合物形態で配合したものである。これらの混合粉
末 1〜20は、ボ−ルミルにて20時間湿式混合し、乾燥し
た後、2MPaの圧力でプレス成形して、16.5mm×16.5mm×
6mm角の圧粉体にした。この圧粉体を温度 1400℃、圧力
4Paの減圧雰囲気中で焼結して、配合組成とほぼ同一組
成の、本発明法による超硬合金 1〜13と、比較用の超硬
合金 14〜20を製作した。Example 1 As a raw material powder, WC powder having an average particle size of 2.6 μm and 2.6 μm, respectively
m Co powder, 2.59 μm Ni powder, 2.5 μm Cr powder, 2.6 μm
Si powder, 1.4 μm Cr 2 N powder, 2.42 μm Cr 3 C 2 powder, 1.
85μm CrSi powder, 1.25μm Cr 3 Si powder, 1.11μm CrSi
Two powders were prepared. Twenty types of mixed powders (Nos. 1 to 20) were prepared by adjusting the composition of the raw material powders shown in Table 1. In Table 1, mixed powders 1 to 13 are obtained by the method of the present invention, and the Cr component and the Si component are blended by the Cr-Si compound. For comparison, the mixed powders 14 to 20 are prepared by mixing the Cr component and the Si component individually or in a compound form other than the Cr-Si compound. These mixed powders 1 to 20 are wet mixed in a ball mill for 20 hours, dried, and then press-molded at a pressure of 2 MPa to obtain 16.5 mm × 16.5 mm ×
6mm square green compact was used. This green compact has a temperature of 1400 ° C and a pressure of
Sintered in a reduced pressure atmosphere of 4 Pa, cemented carbides 1 to 13 according to the method of the present invention and cemented carbides 14 to 20 for comparison, which have almost the same composition as the compounded composition, were manufactured.
【００１９】得られた本発明法による超硬合金 1〜13
と、比較用の超硬合金 14〜20は、次に示す条件のクラ
ック抵抗試験、酸化試験、抗折試験、硬さ試験を行っ
た。さらに、WC粒子の平均粒子径を求めるため、ＳＥＭ
観察を行った。これらの試験結果並びに観察結果を表２
に示す。The obtained cemented carbides according to the method of the present invention 1 to 13
Then, the cemented carbides 14 to 20 for comparison were subjected to a crack resistance test, an oxidation test, a bending test and a hardness test under the following conditions. Furthermore, to obtain the average particle size of WC particles, SEM
Observed. Table 2 shows these test results and observation results.
Shown in.
【００２０】(a) クラック抵抗試験
本発明における破壊靭性はクラック抵抗の値(kN/mm)で
評価した。即ち、機械研摩の後、3μm及び1μmのダイヤ
モンド砥粒を用いて鏡面研摩した試料面に、ビッカ−ス
圧子により荷重 1.47kNで圧痕を５箇所打ち、圧痕端か
ら延びたクラック長さ(mm)を測定し、荷重(kN)をクラッ
ク長さ(mm)で除した値とした。このクラック抵抗は、結
合相の組成が僅かに変わっても顕著な変化を示し、本発
明においては、一般に用いられているＳＥＰＢ法よりも
有効と考えられる。クラック抵抗は、表２の本発明法に
よる超硬合金 8〜10と比較用の超硬合金 14〜18の結果
から分かるように、CrとSiの配合形態（Cr、Si、Cr
3C2、Cr2N、Cr-Si化合物）に大きく影響され、Cr-Si化
合物の配合により著しく向上する。特に、本発明法によ
る超硬合金 10のCrSi2の配合による向上が顕著である。
また、本発明法による超硬合金 6、7のように、結合相
（Co、Ni）量の増加に伴い著しく向上する。(A) Crack resistance test Fracture toughness in the present invention was evaluated by the value of crack resistance (kN / mm). That is, after mechanical polishing, 5 indentations were made with a Vickers indenter at a load of 1.47 kN on the sample surface mirror-polished with 3 μm and 1 μm diamond abrasive grains, and the crack length extending from the indentation end (mm) Was measured and the load (kN) was divided by the crack length (mm). This crack resistance shows a remarkable change even if the composition of the binder phase slightly changes, and is considered to be more effective than the generally used SEPB method in the present invention. As can be seen from the results of the cemented carbides 8 to 10 according to the method of the present invention and the cemented carbides 14 to 18 for comparison in Table 2, the crack resistance is a combination of Cr and Si (Cr, Si, Cr).
3 C 2 , Cr 2 N, Cr-Si compound), and significantly improved by blending Cr-Si compound. In particular, the improvement of the cemented carbide 10 by the method of the present invention by the addition of CrSi 2 is remarkable.
Further, as with the cemented carbides 6 and 7 produced by the method of the present invention, it is remarkably improved as the amount of binder phase (Co, Ni) is increased.
【００２１】(b) 酸化試験
酸化試験は、本発明法による超硬合金と比較用の超硬合
金について、試料形状を13.5mm×13.5mm×4.6mm角と
し、温度 800℃、保持時間 1hの条件で行い酸化減量(mg
/cm2・h)を測定した。ここで酸化減量とは、加熱保持に
より形成される酸化物層を除去し、最初の試料片からの
減少重量を求めた値であって、この値が小さいほど耐酸
化性が良い。耐酸化性は、クラック抵抗と同様に、Crの
配合形態により異なり、Cr-Si化合物の配合によるもの
が良い。結合相の量を増加させるとさらに向上する。(B) Oxidation test In the oxidation test, the cemented carbide according to the method of the present invention and the cemented carbide for comparison were set to have a sample shape of 13.5 mm × 13.5 mm × 4.6 mm square at a temperature of 800 ° C. and a holding time of 1 h. Oxidation weight loss (mg
/ cm 2 · h) was measured. Here, the oxidation weight loss is a value obtained by removing the oxide layer formed by heating and holding, and determining the weight loss from the first sample piece. The smaller this value, the better the oxidation resistance. Similar to the crack resistance, the oxidation resistance varies depending on the Cr compounding form, and it is preferable to use the Cr-Si compound compounding. It is further improved by increasing the amount of binder phase.
【００２２】[0022]
【表１】 [Table 1]
【００２３】[0023]
【表２】 [Table 2]
【００２４】(c) 抗折試験
抗折試験は、試料形状 4mm×8mm×30mm角、支点間距離
25mm、３点曲げの条件で、クラック抵抗試験及び酸化試
験と同じ超硬合金について行った。抗折力(MPa)は、Cr-
Si化合物の配合により向上するが、結合相の量の増加に
伴い低下する傾向にある。(C) Bending test The bending test is a sample shape of 4 mm x 8 mm x 30 mm square, distance between fulcrums
The same cemented carbide as the crack resistance test and the oxidation test was performed under the conditions of 25 mm and 3-point bending. The transverse rupture strength (MPa) is Cr-
Although it is improved by blending the Si compound, it tends to decrease as the amount of the binder phase increases.
【００２５】(d) 硬さ試験
硬さ試験は、本発明法による超硬合金及び比較用の超硬
合金について、鏡面研摩した試料面にビッカ−ス圧子を
荷重 294Nで圧痕を３箇所打ち、圧痕長さを測定するこ
とにより求めた。硬さは、Crの配合形態による差異は認
められないが、結合相の量の増加に伴い低下する。(D) Hardness test In the hardness test, the cemented carbide according to the method of the present invention and the cemented carbide for comparison were dented at three points with a Vickers indenter with a load of 294 N on the mirror-polished sample surface. It was determined by measuring the indentation length. The hardness does not differ depending on the Cr compounding form, but decreases as the amount of the binder phase increases.
【００２６】(e) WC粒子の平均粒子径
WC粒子の平均粒子径は、直接倍率 ×3000のＳＥＭ観察
像の中の、約1000個のWC粒子について画像解析を行い、
WC粒子と同一面積の円相当径を算出することにより求め
た。(a)〜(d)の試験結果とWC粒子の平均粒子径との相関
性をみると、クラック抵抗は、WC粒子を粗大化させると
向上するが、抗折力は逆に低下する。また、硬さはWC粒
子が微細なほど硬くなる。(E) Average particle size of WC particles The average particle size of WC particles is determined by performing image analysis on about 1000 WC particles in a SEM observation image of direct magnification × 3000.
It was determined by calculating the equivalent circle diameter of the same area as the WC particles. Looking at the correlation between the test results of (a) to (d) and the average particle size of the WC particles, the crack resistance is improved when the WC particles are coarsened, but the transverse rupture strength is decreased. Further, the hardness becomes harder as the WC particles become finer.
【００２７】実施例２
前記実施例１の混合粉末 8、10、16、17をそれぞれ直径
60mm×長さ60mmの円筒形ステンレス製容器に充填の後、
容器内部の到達圧力が0.15Paの脱気処理を施した後密封
し、温度 1300℃、圧力 140MPaの雰囲気条件でＨＩＰ処
理を行い、配合組成とほぼ同一組成の、本発明法による
合金 21、22と、比較用の合金 23、24を製作した。これ
らの合金について、実施例１と同様に、クラック抵抗試
験、酸化試験、抗折試験、硬さ試験の試料を製作し、試
験した。WC粒子の平均粒子径も、実施例１と同様に、Ｓ
ＥＭ観察により求めた。これらの結果を表３に示す。Example 2 The mixed powders of Example 1, 8, 10, 16 and 17 were respectively made to have a diameter of
After filling a cylindrical stainless steel container of 60 mm × length 60 mm,
The ultimate pressure inside the container was 0.15 Pa, which was degassed and then sealed, and then HIPed under the atmospheric conditions of a temperature of 1300 ° C. and a pressure of 140 MPa. Then, alloys 23 and 24 for comparison were manufactured. Samples for crack resistance test, oxidation test, bending test and hardness test were prepared and tested for these alloys in the same manner as in Example 1. The average particle size of the WC particles is S as in Example 1.
It was determined by EM observation. The results are shown in Table 3.
【００２８】[0028]
【表３】 [Table 3]
【００２９】表３の本発明法による超硬合金21、22及び
比較用の超硬合金23、24の結果から分かるように、ＨＩ
Ｐ処理により、何れの合金もクラック抵抗が向上する。
但し、Cr-Si化合物、Cr3C2、Cr2N等のCrの配合形態に大
きく影響され、Cr-Si化合物の配合による効果が顕著で
ある。また、抗折力も著しく向上している。しかし、耐
酸化性と硬さは大きな変化が認められない。WCの平均粒
子径は、僅かであるが、粗大化傾向が認められる。As can be seen from the results of cemented carbides 21 and 22 according to the method of the present invention and comparative cemented carbides 23 and 24 in Table 3, the HI
The P treatment improves the crack resistance of any alloy.
However, the compounding form of Cr such as Cr-Si compound, Cr 3 C 2 and Cr 2 N is greatly affected, and the effect of compounding the Cr-Si compound is remarkable. Also, the transverse rupture strength is remarkably improved. However, there is no significant change in oxidation resistance and hardness. Although the average particle size of WC is small, a tendency toward coarsening is observed.
【００３０】実施例３
ＳＮＣＭ鋼からなる直径300mmの芯材の周囲に内径360m
m、厚さ10mmの軟鋼製のＨＩＰ処理用容器を同心状に配
置し、底面を溶接で封着した。その上で芯材の外周部と
ＨＩＰ処理用容器の内面との間に形成した空間部に、外
層材として平均粒子径2.6μmのWC粉末を75体積％、2.6
μmのCo粉末を16体積％、2.6μmのNi粉末を7体積％、1.
1μmのCrSi2粉末を2体積％の配合組成からなる混合粉末
を充填した。充填後、容器の内部を脱気処理して密封し
た。次いで、ＨＩＰ装置に入れ、温度 1300℃、圧力 14
0MPaの雰囲気条件で２時間、ＨＩＰ処理により焼結し
た。ＨＩＰ処理後、ＨＩＰ処理用容器等を機械加工によ
り旋削除去し、外径330mm、長さ500mmの本発明の複合超
硬合金ロールを得た。本発明の複合超硬合金ロールの内
層材（芯材）としては、強靱なＳＮＣＭ材等の合金鋼を
用いその化学成分は、重量比でC:0.1〜0.8％、Si:0.2〜
1.0％、Mn:0.2〜1.0％、P:0.03％以下、S:0.03％以下、
Ni:0.1〜5.0％、Cr:0.1〜5.0％、Mo:0.1〜5.0％を含む
のが好ましい。Example 3 An inner diameter of 360 m around a core material made of SNCM steel and having a diameter of 300 mm
An HIP treatment container made of m and having a thickness of 10 mm was concentrically arranged, and the bottom surface was welded and sealed. 75% by volume of 2.6% WC powder having an average particle diameter of 2.6 μm was used as the outer layer material in the space formed between the outer periphery of the core material and the inner surface of the HIP processing container.
16% by volume of Co powder of μm, 7% by volume of Ni powder of 2.6 μm, 1.
1 μm of CrSi 2 powder was filled with a mixed powder having a composition of 2% by volume. After filling, the inside of the container was deaerated and sealed. Then, put it in the HIP device, temperature 1300 ℃, pressure 14
It was sintered by HIP treatment for 2 hours under an atmospheric condition of 0 MPa. After the HIP treatment, the HIP treatment container and the like were removed by machining to obtain a composite cemented carbide roll of the present invention having an outer diameter of 330 mm and a length of 500 mm. As the inner layer material (core material) of the composite cemented carbide roll of the present invention, an alloy steel such as a tough SNCM material is used, and its chemical composition is C: 0.1-0.8% by weight ratio, Si: 0.2-
1.0%, Mn: 0.2-1.0%, P: 0.03% or less, S: 0.03% or less,
It is preferable to contain Ni: 0.1 to 5.0%, Cr: 0.1 to 5.0%, Mo: 0.1 to 5.0%.
【００３１】得られた本発明の複合超硬合金ロールの内
層材と超硬合金外層材との接合界面部の接合状態を超音
波を使って検査したところ、外層材は内層材の外表面に
強固に接合され、接合不良は全く観察されず、またクラ
ックも認められなかった、さらに、本発明の複合超硬合
金ロールを熱間圧延用ロールとして使用したところ、優
れた耐摩耗性、耐酸化性及び耐事故性が得られた。When the joining state of the joining interface between the inner layer material and the outer layer material of the cemented carbide of the obtained composite cemented carbide roll of the present invention was inspected using ultrasonic waves, the outer layer material was found to be on the outer surface of the inner layer material. Strongly joined, no joint failure was observed, and no cracks were observed. Furthermore, when the composite cemented carbide roll of the present invention was used as a hot rolling roll, it showed excellent wear resistance and oxidation resistance. And accident resistance were obtained.
【００３２】[0032]
【発明の効果】本発明の方法により得られる高靭性超硬
合金は、比較用の超硬合金に比べて、硬さは同等水準で
あるが、高強度、高靭性であり、さらに耐酸化性にも優
れている。このため、高温、高荷重下で使用される圧延
用ロ−ル、各種ダイス等へ適用して優れた性能を発揮す
る。The high toughness cemented carbide obtained by the method of the present invention has the same level of hardness as the comparative cemented carbide, but has high strength and high toughness, and further has high oxidation resistance. Is also excellent. Therefore, it is applied to rolling rolls, various dies, etc. used under high temperature and high load, and exhibits excellent performance.
───────────────────────────────────────────────────── フロントページの続き (72)発明者 大畑 拓巳 北九州市若松区北浜一丁目９番１号 日 立金属株式会社若松工場内 (72)発明者 福沢 宏 北九州市若松区北浜一丁目９番１号 日 立金属株式会社若松工場内 (58)調査した分野(Int.Cl.7，ＤＢ名) C22C 1/05,29/08 B22F 3/15,5/00 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takumi Ohata 1-9-1, Kitahama, Wakamatsu-ku, Kitakyushu City Wakamatsu Plant, Nittsu Metal Co., Ltd. (72) Hiroshi Fukuzawa 1-9-1, Kitahama, Wakamatsu-ku, Kitakyushu Issue Wakamatsu Plant, Nittsu Metal Co., Ltd. (58) Fields surveyed (Int.Cl. 7 , DB name) C22C 1 / 05,29 / 08 B22F 3 / 15,5 / 00
Claims (9)
5％、Cr-Si化合物粉末 0.5〜10％、WC粉末 50〜79.5％
を含む混合粉末を焼結することを特徴とする高靭性超硬
合金の製造方法。1. Co powder 15 to 25% and Ni powder 5-1 by volume ratio.
5%, Cr-Si compound powder 0.5-10%, WC powder 50-79.5%
A method for producing a high toughness cemented carbide, which comprises sintering a mixed powder containing
の何れか一種、又は二種以上の混合物であることを特徴
とする請求項１記載の高靭性超硬合金の製造方法。2. The production of a high toughness cemented carbide according to claim 1, wherein the Cr—Si compound is any one of Cr 3 Si, CrSi, and CrSi 2 or a mixture of two or more thereof. Method.
ことを特徴とする請求項１又は２記載の高靭性超硬合金
の製造方法。3. The method for producing a high toughness cemented carbide according to claim 1, wherein the WC powder has an average particle size of 1.0 to 10 μm.
0〜1450℃の減圧雰囲気中で焼結することを特徴とする
請求項１乃至３の何れか記載の高靭性超硬合金の製造方
法。4. A temperature of 135 after press molding of the mixed powder.
The method for producing a high toughness cemented carbide according to any one of claims 1 to 3, wherein the sintering is performed in a reduced pressure atmosphere of 0 to 1450 ° C.
容器に充填の後、容器の内部を脱気処理して密封し、容
器に充填密封された前記混合粉末を温度 1200〜1400
℃、圧力 150MPa以下の雰囲気条件で熱間等方圧加圧処
理により焼結することを特徴とする請求項１乃至３の何
れか記載の高靭性超硬合金の製造方法。5. The container for hot isostatic pressing is filled with the mixed powder, the inside of the container is deaerated and sealed, and the mixed powder filled in the container is sealed at a temperature of 1200 to 1400
The method for producing a high toughness cemented carbide according to any one of claims 1 to 3, wherein the sintering is carried out by hot isostatic pressing under an atmospheric condition of ℃ and a pressure of 150 MPa or less.
金からなる外層材が焼結された複合超硬合金ロールにお
いて、外層材が体積比でCo粉末 15〜25％、Ni粉末 5〜1
5％、Cr-Si化合物粉末 0.5〜10％、WC粉末 50〜79.5％
を含む混合粉末を焼結したことを特徴とする複合超硬合
金ロール。6. A composite cemented carbide roll in which an outer layer material made of cemented carbide is sintered on the outer periphery of an inner layer material made of alloy steel, the outer layer material being 15 to 25% by volume of Co powder and 5% by weight of Ni powder. ~ 1
5%, Cr-Si compound powder 0.5-10%, WC powder 50-79.5%
A composite cemented carbide roll obtained by sintering a mixed powder containing a.
方圧加圧処理用の容器の内面との間に形成した空間部
に、外層材として体積比でCo粉末 15〜25％、Ni粉末 5
〜15％、Cr-Si化合物粉末 0.5〜10％、WC粉末 50〜79.5
％を含む混合粉末を充填の後、容器の内部を脱気処理し
て密封し、容器に充填密封された前記混合粉末を温度 1
200〜1400℃、圧力 150MPa以下の雰囲気条件で熱間等方
圧加圧処理により焼結したことを特徴とする複合超硬合
金ロール。7. Co powder 15 to 25% by volume as an outer layer material in the space formed between the outer peripheral portion of the inner layer material made of alloy steel and the inner surface of the container for hot isostatic pressing. , Ni powder 5
~ 15%, Cr-Si compound powder 0.5 ~ 10%, WC powder 50 ~ 79.5
%, The inside of the container is degassed and sealed, and the container is filled with the mixed powder at a temperature of 1
A composite cemented carbide roll that is sintered by hot isostatic pressing under an atmosphere condition of 200 to 1400 ° C and a pressure of 150 MPa or less.
の何れか一種、又は二種以上の混合物であることを特徴
とする請求項６又は７に記載の複合超硬合金ロール。8. The composite cemented carbide according to claim 6 or 7, wherein the Cr-Si compound is any one of Cr 3 Si, CrSi, and CrSi 2 or a mixture of two or more thereof. roll.
ことを特徴とする請求項６乃至８の何れか記載の複合超
硬合金ロール。9. The composite cemented carbide roll according to claim 6, wherein the WC powder has an average particle size of 1.0 to 10 μm.
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|---|---|---|---|
| JP17066595A JP3511740B2 (en) | 1994-07-07 | 1995-07-06 | Method for producing high toughness cemented carbide and composite cemented carbide roll |
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|---|---|---|---|
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| JP6-156295 | 1994-07-07 | ||
| JP17066595A JP3511740B2 (en) | 1994-07-07 | 1995-07-06 | Method for producing high toughness cemented carbide and composite cemented carbide roll |
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| Publication Number | Publication Date |
|---|---|
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| JP3511740B2 true JP3511740B2 (en) | 2004-03-29 |
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|---|---|---|---|---|
| SE517473C2 (en) * | 1996-07-19 | 2002-06-11 | Sandvik Ab | Roll for hot rolling with resistance to thermal cracks and wear |
| JP2002275506A (en) * | 2001-03-16 | 2002-09-25 | Hitachi Metals Ltd | Method of manufacturing rolling roll and rolling roll using the same |
| GB0816836D0 (en) | 2008-09-15 | 2008-10-22 | Element Six Holding Gmbh | Steel wear part with hard facing |
-
1995
- 1995-07-06 JP JP17066595A patent/JP3511740B2/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0873964A (en) | 1996-03-19 |
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