JP4295491B2 - Copper-tungsten alloy and method for producing the same - Google Patents
Copper-tungsten alloy and method for producing the same Download PDFInfo
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Description
【０００１】
【発明の属する技術分野】
本発明は、放電加工用電極や接点材料、伝熱材料として使用される銅−タングステン合金およびその製造方法に関する。
【０００２】
【従来の技術】
放電加工用電極や接点材料、伝熱材料として使用される銅−タングステン合金は、優れた塑性加工性と、高熱伝導性が要求されている。その製造方法としては、タングステン単体粉末をプレスした圧粉体を焼結し、この焼結体に銅を含浸させて合金を得る溶浸法と、銅とタングステンの混合粉を熱間加圧焼結（以下「ＨＩＰ処理」と称する。）して高密度の合金を得る焼結法などがある。ＨＩＰ処理は、加圧しながら残留空孔を拡散することにより、粉末材料などを偏りなく緻密化させることができるので、１）寸法精度が優れる、２）材料歩留が優れる、３）異形品の製造に適する、４）複合材料・複合部品の製造に適するなどの溶浸法より優れた利点を有している。
【０００３】
ＨＩＰ処理の代表的なものとして成形用容器を用いるカプセル法と、成形用容器を用いずＨＩＰ処理過程で内部空孔が閉塞化されることを利用したカプセルフリー法がある。カプセル法は、金属混合粉末などの被処理体を、圧媒ガスに対して気密な材料で作製した成形用容器（カプセル）内に封入し、脱気を行なった後ＨＩＰ処理を行なう方法であり、この方法は通常の焼結では緻密に焼結できないような材料に対しても高密度化が行なえる。これらの利点より、従来、銅粉とタングステン粉の混合粉を原料とする銅−タングステン合金の製造方法として鋼製成形容器などを利用した上記カプセル法が用いられている。
【０００４】
また、銅粉とタングステン粉の混合粉を原料とする銅−タングステン合金の製造において、銅の配合量によって高純度シリカガラスカプセルなどを用いたカプセル法とカプセルを使用しないカプセルフリー法とを適宜用い、カプセルフリー法を用いる場合には、開放孔を閉塞化するため予備焼結を行なう製造方法なども開示されている（例えば、特許文献１参照。）。
【０００５】
【特許文献１】
特開平５−２７１７０２号公報 （特許請求の範囲）
【０００６】
【発明が解決しようとする課題】
しかしながら、ＨＩＰ処理による焼結法によって製造した銅−タングステン合金は、その塑性加工性の変動が大きく再現性の良い加工結果が得られないという問題がある。
また、一般的にＨＩＰ処理時の温度を上げるほど塑性加工性が向上することが知られているが、上記カプセル法による銅−タングステン合金の製造過程において、ＨＩＰ処理温度が高温となると、鋼製成形容器と銅−タングステン合金材料との接触面において鋼製容器の鉄成分が合金材料に混入し、銅−タングステン合金の熱伝導度を低下させるという問題がある。特に、ＨＩＰ処理温度が 1083 ℃（銅の融点）を超えた場合にはこの鉄汚染が起こりやすくなり、合金の熱伝導度を著しく低下させるという問題がある。
また、ＨＩＰ処理における容器としてシリカガラスなどを用いる場合では、実用性、量産性に乏しく、処理コストが高くなるという問題がある。また、上記予備焼結を行なうカプセルフリー法は、銅の溶解を利用して表面の開放孔を閉塞化し、カプセルを用いた場合と同様の効果を得るものであるため、銅−タングステン合金において銅の配合量が極端に少ない場合では、安定な中間焼結体が得られず該方法を用いることができないという問題がある。
【０００７】
本発明は、このような問題に対処するためになされたもので、優れた塑性加工性および熱伝導性を有する銅−タングステン合金、およびこの優れた特性を有する合金を安価に製造でき、かつ、銅とタングステンを任意の配合割合で合金化できる銅−タングステン合金の製造方法を提供することを目的とする。
【０００８】
【課題を解決するための手段】
本発明の銅−タングステン合金は、粉末焼結法による銅−タングステン合金であって、その機械的性質として伸びが 4 ％以上、絞りが 4 ％以上であり、また熱伝導度が 150 W/(m・℃)以上であることを特徴とする。
【０００９】
本発明において、塑性加工性の程度を示す「伸び（％）」とは、引張試験において銅−タングステン合金の試験片が破断した時の伸びた長さを試験前の合金長さで割った百分率（％）をいい、「絞り（％）」とは、引張試験で破断した合金片の最小断面積Ａと最初の断面積Ａ0との差（小さくなった面積）を最初の合金片断面積Ａ0で割った百分率％をいう。また、「熱伝導度 W/(m・℃) 」とは、銅−タングステン合金において、距離１ｍにつき、１℃の温度差がある場合に該合金の１ｍ2の断面を通って１秒間に伝わる熱量をいう。
【００１０】
本発明の銅−タングステン合金の製造方法は、銅粉とタングステン粉とを所定割合で混合した混合粉を熱間加圧焼結する銅−タングステン合金の製造方法であって、該製造方法は、上記混合粉を非鉄製の焼成用容器に収納し、または、上記混合粉をプレス加工した圧粉体を非鉄製の冶具で把持し 1083 ℃以上、1400 ℃未満で焼成する予備処理工程と、該予備処理工程で得た焼成体を成形用容器に収納して 950 ℃以上、1083 ℃未満で熱間加圧焼結する工程とを備えてなることを特徴とする。
【００１１】
上記成形用容器は、鋼製容器であることを特徴とする。また、上記非鉄製の焼成用容器および冶具は、セラミックス製、黒鉛製、またはタングステン製であることを特徴とする。
【００１２】
本発明の銅−タングステン合金の製造方法は、ＨＩＰ処理前に予め、銅粉とタングステン粉との混合粉をセラミックス製容器などの非鉄製容器に収納して、または、圧粉体の場合は非鉄製の冶具で把持して銅の融点以上の温度で焼成し、その後に銅の融点未満の温度でＨＩＰ処理することにより、ＨＩＰ処理を銅の融点以上の温度でなした合金と同様の塑性加工性を有しつつ、焼成加工時およびＨＩＰ処理時において鉄成分の混入が起こらないので優れた熱伝導性も併せて有する銅−タングステン合金を得ることができる。
また、ＨＩＰ処理を銅の融点より低い温度で行なうことにより、成形用容器として安価な鋼製容器の使用が可能となり、ＨＩＰ処理のコストを削減することができる。また、ＨＩＰ処理を常に容器を用いて行なうため、カプセルフリー法では製造することのできない配合割合の銅−タングステン合金も製造することができる。
【００１３】
【発明の実施の形態】
本発明の銅−タングステン合金の製造方法は、（Ａ）銅粉とタングステン粉との混合粉を所定温度範囲で予め焼成する予備処理工程と、（Ｂ）これを所定温度範囲で熱間加圧焼結（ＨＩＰ処理）する工程とを備えている。各工程（Ａ）、（Ｂ）の詳細を以下に説明する。
（Ａ）予備処理工程
合金原料として、それぞれ数μm 〜 数十μmの粒子径とした銅粉とタングステン粉とを混合した混合粉を準備する。予備処理工程後のＨＩＰ処理は、成形用容器を用いて行なうため、銅の配合量は規制されず、銅粉およびタングステン粉の配合割合は合金を形成できる範囲で任意とすることができる。また、各粉末は合金の熱伝導度や塑性加工性の低下などを防止するため、粉末中の鉄、クロム、ニッケルなどの不純物の含有量を規制することが好ましい。具体的には、合金重量に対して各成分を 0.05 重量％以下とすることが好ましい。
上記合金材料である混合粉を焼成用容器に収納し、 1083 ℃以上、1400 ℃未満で焼成する。また、混合粉をプレス加工した圧粉体を用いる場合では、容器は必要なく、この圧粉体自体を冶具で把持し上記温度範囲で焼成する。焼成は、水素気流中で数時間行なう。焼成用容器および冶具は、鉄成分の混入が起こらないように非鉄製であればよく、セラミックス製、黒鉛製、またはタングステン製などを好適に用いることができる。なお、上記温度範囲上限を 1400 ℃としたのは、この温度以上となると、銅の蒸発が激しくなり実用的には操業できなくなるためである。
【００１４】
（Ｂ）ＨＩＰ処理工程
予備処理工程で得た焼成体を成形用容器に収納して 950 ℃以上、1083 ℃未満でＨＩＰ処理する。成形用容器は、シリカガラス、銅、鋼製などの任意の容器を用いることが可能である。処理コストを削減できることから、鋼製容器を用いることが好ましい。ＨＩＰ処理は、十分な密度を得ることができる圧力下で数時間行なう。なお、ＨＩＰ処理温度の下限を 950℃としたのは、この温度以下となると、ＨＩＰ処理が実用的には進行しなくなるためである。
【００１５】
上記（Ａ）予備処理工程において温度範囲下限の 1083 ℃は銅の融点であり、該温度以上で混合粉（またはその圧粉体）を焼成することにより、混合粉中の銅粉が溶融しタングステン粉との密着性が増す。これにより、ＨＩＰ処理前において塑性加工性を潜在的に改善させることができる。次に、予備処理工程で得られた焼成体を（Ｂ）ＨＩＰ処理工程において、ＨＩＰ処理を温度 1083 ℃未満で行なうことにより、銅の溶解が起こらず、溶解した銅と鋼製容器との接触による鋼製容器鉄成分の合金材料への混入が防止でき、銅−タングステン合金の熱伝導度の低下を抑制することができる。以上より該製造方法によって得られた銅−タングステン合金は、塑性加工性に優れ、かつ高熱伝導性を有するため、放電加工用電極や接点材料、伝熱材料などに好適に用いることができる。
【００１６】
実際の製造現場では銅−タングステン合金の製造コストを抑えるために、ＨＩＰ処理容器として鋼製容器を使用することは必須であるが、従来、上述のように鋼製容器の使用は鉄汚染による合金の熱伝導度低下の問題があり、また、ＨＩＰ処理時における鋼製容器と銅−タングステン合金との接触自体を防止するには多大のコストが必要となる問題があった。これに対し本発明の製造方法では、合金に十分な塑性加工性が必要な場合でも、ＨＩＰ処理前に予め焼成を行なうことにより、ＨＩＰ処理を銅の融点より低い温度で行なうことを可能としたため、安価な鋼製容器を用いることができ製造コストを抑えられる。また、この鋼製容器を用いたカプセル法によりＨＩＰ処理を行なうので、カプセルフリー法の場合にネックとなる安定な中間焼結体を得るために必要な銅の配合量を考慮する必要がなく、任意の配合割合の銅−タングステン合金を製造することができる。
【００１７】
【実施例】
実施例１〜実施例１１、比較例１〜１２
粒径 1 〜 30 μmの銅粉末（粉末中の鉄、クロム、ニッケルの含有量は、合金重量に対してそれぞれ 0.05 重量％以下）と、粒径 1 〜 3 μmのタングステン粉末（粉末中の鉄、クロム、ニッケルの含有量は、合金重量に対してそれぞれ 0.05 重量％以下）とを表１に示す重量比で配合しよく混ぜ合わせた。この混合粉を表１に示す焼成用容器に入れて水素気流中で 5 時間焼成した。得られた焼成体を鋼製容器に入れて脱気後、1200kgf/cm2の圧力下、表１の温度条件下で 4 時間ＨＩＰ処理した。得られた合金から試験片を切り出し鉄の含有量、熱伝導度、機械的性質の合金の伸び、絞りを測定した。結果を表１に示す。
【表１】
表１より実施例１〜７、比較例１〜８（銅：タングステン＝35：65）において、実施例１〜７すべてで優れた熱伝導度および塑性加工性を有することが分かる。なお、熱伝導度が優れるとは、具体的に150 W/(m・℃)以上程度であり、塑性加工の成否は伸び 4 ％以上、絞り 4 ％以上が目安となる。また、実施例１、３および４から、焼成温度が高いほど、得られた合金の伸び、絞り値が高く、塑性加工性に優れることが分かる。
これに対し、予備処理として焼成を行なわず、直接 1083 ℃以上でＨＩＰ処理を行なった比較例２〜４では、容器からの鉄汚染が進行し合金中の鉄含有量が著しく増加しており、熱伝導度も各実施例と比較して低下している。また、焼成を鋼製容器を用いて1083℃以上で行なった比較例５についても、鉄汚染の進行および熱伝導度の低下が見られる。
【００１９】
ＨＩＰ処理温度を一定とした実施例８、９、比較例９、１０（銅：タングステン＝50：50）において、焼成温度が銅の融点（ 1083 ℃）付近を境として塑性加工性が急激に変化していることが分かる。すなわち、焼成を1083 ℃以上で行なった実施例８、９では非常に優れた塑性加工性を示しているが、それ以下の温度で焼成した比較例９、１０では、塑性加工性が劣っている。
この傾向は、上記（銅：タングステン＝35：65）の場合においても同様に見られる。
【００２０】
実施例１０、１１、比較例１１、１２（銅：タングステン＝15：85）において、銅の融点以下で焼成を行なった比較例１２は、塑性加工性に劣ることが分かる。また、上記比較例５と同様に、鋼製容器を用いて銅の融点以上で焼成を行なった比較例１１は鉄汚染の進行が見られ熱伝導度も低い。
【００２１】
全体を通して、銅−タングステン合金では、製造条件が同じであれば銅の含有量が多いほど、塑性加工性および熱伝導度に優れることが分かる（実施例１、８、１１）。また、どの配合割合においても本発明の製造方法を用いた実施例では、優れた塑性加工性および熱伝導度、具体的には、伸び 4 ％以上、絞り 4 ％以上、および熱伝導度 150 W/(m・℃)以上を有する銅−タングステン合金が得られた。
【００２２】
【発明の効果】
本発明の銅−タングステン合金は、粉末焼結法による銅−タングステン合金であって、その機械的性質として伸びが 4 ％以上、絞りが 4 ％以上であり、また熱伝導度が 150 W/(m・℃)以上であるので、塑性加工性に優れ、かつ高熱伝導性を有するため、放電加工用電極や接点材料、伝熱材料などに好適に用いることができる。
【００２３】
本発明の銅−タングステン合金の製造方法は、銅粉とタングステン粉とを所定割合で混合した混合粉を熱間加圧焼結する銅−タングステン合金の製造方法であって、該製造方法は、上記混合粉を非鉄製の焼成用容器に収納し、または、上記混合粉をプレス加工した圧粉体を非鉄製の冶具で把持し 1083 ℃以上、1400 ℃未満で焼成する予備処理工程と、該予備処理工程で得た焼成体を成形用容器に収納して 950 ℃以上、1083 ℃未満で熱間加圧焼結する工程とを備えてなるので、ＨＩＰ処理を銅の融点以上の温度でなした合金と同様の塑性加工性を有し、さらに、焼成加工時およびＨＩＰ処理時において鉄成分の混入が起こらないため高熱伝導性も併せて有する銅−タングステン合金を得ることができる。
【００２４】
上記成形用容器が鋼製容器であるので、ＨＩＰ処理のコストを削減することができる。また、ＨＩＰ処理を常に容器を用いて行なうため、カプセルフリー法では製造することのできない配合割合の銅−タングステン合金も製造することができる。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a copper-tungsten alloy used as an electrode for electrical discharge machining, a contact material, and a heat transfer material, and a method for producing the same.
[0002]
[Prior art]
Copper-tungsten alloys used as an electric discharge machining electrode, contact material, and heat transfer material are required to have excellent plastic workability and high thermal conductivity. The manufacturing method includes sintering a green compact obtained by pressing a single tungsten powder, impregnating the sintered body with copper and obtaining an alloy, and hot pressing and sintering a mixed powder of copper and tungsten. There is a sintering method for obtaining a high-density alloy by sintering (hereinafter referred to as “HIP treatment”). The HIP treatment can densify the powder material and the like by diffusing residual vacancies while applying pressure, so that 1) excellent dimensional accuracy, 2) excellent material yield, and 3) deformed products. Suitable for manufacturing 4) It has advantages over infiltration methods such as being suitable for manufacturing composite materials and composite parts.
[0003]
As a representative example of the HIP processing, there are a capsule method using a molding container and a capsule-free method utilizing the fact that internal vacancies are blocked during the HIP processing process without using the molding container. The capsule method is a method in which an object to be processed such as a metal mixed powder is enclosed in a molding container (capsule) made of a material that is airtight to a pressure medium gas, deaerated, and then subjected to HIP processing. This method can increase the density even for materials that cannot be densely sintered by ordinary sintering. Because of these advantages, the above-described capsule method using a steel molded container or the like has been conventionally used as a method for producing a copper-tungsten alloy using a mixed powder of copper powder and tungsten powder as a raw material.
[0004]
In addition, in the production of copper-tungsten alloy using a mixed powder of copper powder and tungsten powder as a raw material, the capsule method using high-purity silica glass capsules and the capsule-free method without using capsules are appropriately used depending on the amount of copper. In the case of using the capsule-free method, a manufacturing method in which pre-sintering is performed to close the open hole is also disclosed (for example, see Patent Document 1).
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 5-271702 (Claims)
[0006]
[Problems to be solved by the invention]
However, the copper-tungsten alloy manufactured by the sintering method using HIP treatment has a problem that the processability with good reproducibility cannot be obtained because the plastic workability varies greatly.
Further, it is generally known that the plastic workability is improved as the temperature at the time of HIP treatment is increased. However, when the HIP treatment temperature becomes high in the process of producing a copper-tungsten alloy by the capsule method, There is a problem that the iron component of the steel container is mixed into the alloy material at the contact surface between the forming container and the copper-tungsten alloy material, and the thermal conductivity of the copper-tungsten alloy is lowered. In particular, when the HIP processing temperature exceeds 1083 ° C. (the melting point of copper), this iron contamination is likely to occur, and there is a problem that the thermal conductivity of the alloy is significantly reduced.
Further, when silica glass or the like is used as a container in HIP processing, there is a problem that the practicality and mass productivity are poor and the processing cost becomes high. In addition, the capsule-free method in which the pre-sintering is performed uses the dissolution of copper to close the open holes on the surface and obtains the same effect as in the case of using the capsule. When the blending amount of is extremely small, there is a problem that a stable intermediate sintered body cannot be obtained and the method cannot be used.
[0007]
The present invention has been made in order to cope with such a problem. A copper-tungsten alloy having excellent plastic workability and thermal conductivity, and an alloy having this excellent characteristic can be produced at low cost, and It aims at providing the manufacturing method of the copper-tungsten alloy which can alloy copper and tungsten in arbitrary mixture ratios.
[0008]
[Means for Solving the Problems]
The copper-tungsten alloy of the present invention is a copper-tungsten alloy produced by a powder sintering method, and its mechanical properties include elongation of 4% or more, drawing of 4% or more, and thermal conductivity of 150 W / ( m · ° C) or more.
[0009]
In the present invention, “elongation (%)” indicating the degree of plastic workability is a percentage obtained by dividing the length of elongation when a copper-tungsten alloy specimen is broken in a tensile test by the alloy length before the test. The “drawing (%)” means the difference (smaller area) between the minimum cross-sectional area A and the initial cross-sectional area A 0 of the alloy piece fractured in the tensile test. Percentage percentage divided by zero . “Thermal conductivity W / (m · ° C.)” is transmitted in 1 second through a 1 m 2 cross section of a copper-tungsten alloy when there is a temperature difference of 1 ° C. per 1 m distance. The amount of heat.
[0010]
The method for producing a copper-tungsten alloy according to the present invention is a method for producing a copper-tungsten alloy, in which a mixed powder obtained by mixing copper powder and tungsten powder in a predetermined ratio is hot-pressurized and sintered. A pretreatment step of storing the mixed powder in a non-ferrous firing container, or gripping the green compact obtained by pressing the mixed powder with a non-ferrous jig and firing at 1083 ° C. or more and less than 1400 ° C .; And a step of storing the fired body obtained in the preliminary treatment step in a molding container and performing hot pressure sintering at 950 ° C. or higher and lower than 1083 ° C.
[0011]
The molding container is a steel container. Further, the non-ferrous firing container and jig are made of ceramics, graphite, or tungsten.
[0012]
The method for producing a copper-tungsten alloy according to the present invention can be obtained by previously storing a mixed powder of copper powder and tungsten powder in a non-ferrous container such as a ceramic container before HIP treatment, or in the case of a green compact. Plastic processing similar to an alloy in which HIP treatment is performed at a temperature higher than the melting point of copper by gripping with an iron jig and firing at a temperature equal to or higher than the melting point of copper, followed by HIP treatment at a temperature lower than the melting point of copper. The copper-tungsten alloy having excellent thermal conductivity can be obtained because the iron component does not enter during firing processing and HIP treatment.
Further, by performing the HIP process at a temperature lower than the melting point of copper, it becomes possible to use an inexpensive steel container as a forming container, and the cost of the HIP process can be reduced. Further, since the HIP treatment is always performed using a container, a copper-tungsten alloy having a blending ratio that cannot be manufactured by the capsule-free method can be manufactured.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
The method for producing a copper-tungsten alloy according to the present invention includes (A) a pretreatment step in which a mixed powder of copper powder and tungsten powder is pre-fired in a predetermined temperature range, and (B) hot pressing this in a predetermined temperature range. And a step of sintering (HIP treatment). The detail of each process (A) and (B) is demonstrated below.
(A) Pretreatment process A mixed powder prepared by mixing copper powder and tungsten powder each having a particle diameter of several μm to several tens of μm is prepared as an alloy raw material. Since the HIP treatment after the preliminary treatment step is performed using a molding container, the amount of copper is not regulated, and the proportion of copper powder and tungsten powder can be arbitrarily set as long as an alloy can be formed. Each powder preferably controls the content of impurities such as iron, chromium and nickel in the powder in order to prevent a decrease in the thermal conductivity and plastic workability of the alloy. Specifically, each component is preferably 0.05% by weight or less with respect to the alloy weight.
The mixed powder, which is the above alloy material, is placed in a firing container and fired at 1083 ° C or higher and lower than 1400 ° C. In the case of using a green compact obtained by pressing mixed powder, a container is not necessary, and the green compact itself is held by a jig and fired in the above temperature range. Firing is performed in a hydrogen stream for several hours. The firing container and the jig may be made of non-ferrous iron so that the iron component does not mix, and ceramic, graphite, or tungsten can be suitably used. The upper limit of the temperature range is set to 1400 ° C. because when the temperature is higher than this temperature, copper evaporates violently and cannot be operated practically.
[0014]
(B) HIP treatment process The fired body obtained in the preliminary treatment process is housed in a molding container and subjected to HIP treatment at 950 ° C or higher and lower than 1083 ° C. Arbitrary containers, such as silica glass, copper, and steel, can be used for the container for molding. Since the processing cost can be reduced, it is preferable to use a steel container. The HIP treatment is performed for several hours under pressure that can obtain a sufficient density. The lower limit of the HIP processing temperature is set to 950 ° C. because the HIP processing does not proceed practically when the temperature is lower than this temperature.
[0015]
In the (A) pretreatment step, the lower temperature range of 1083 ° C. is the melting point of copper, and by firing the mixed powder (or its green compact) above this temperature, the copper powder in the mixed powder is melted and tungsten Adhesion with powder increases. This can potentially improve plastic workability before HIP processing. Next, the fired body obtained in the preliminary treatment step (B) in the HIP treatment step is subjected to HIP treatment at a temperature of less than 1083 ° C., so that the copper does not dissolve and the molten copper contacts the steel container. It is possible to prevent the steel container iron component from being mixed into the alloy material by suppressing the decrease in the thermal conductivity of the copper-tungsten alloy. As described above, the copper-tungsten alloy obtained by the production method is excellent in plastic workability and has high thermal conductivity, and therefore can be suitably used for an electrode for electrical discharge machining, a contact material, a heat transfer material, and the like.
[0016]
In an actual manufacturing site, it is essential to use a steel container as a HIP processing container in order to reduce the manufacturing cost of a copper-tungsten alloy. Conventionally, as described above, the use of a steel container is an alloy caused by iron contamination. In addition, there is a problem that a great deal of cost is required to prevent the contact between the steel container and the copper-tungsten alloy during HIP processing. On the other hand, in the manufacturing method of the present invention, even when sufficient plastic workability is required for the alloy, it is possible to perform the HIP treatment at a temperature lower than the melting point of copper by performing firing in advance before the HIP treatment. Inexpensive steel containers can be used, and the manufacturing cost can be reduced. In addition, since the HIP process is performed by the capsule method using this steel container, it is not necessary to consider the amount of copper necessary to obtain a stable intermediate sintered body that becomes a neck in the case of the capsule-free method, A copper-tungsten alloy having an arbitrary mixing ratio can be manufactured.
[0017]
【Example】
Examples 1 to 11 and Comparative Examples 1 to 12
Copper powder with a particle size of 1 to 30 μm (the content of iron, chromium and nickel in the powder is not more than 0.05% by weight with respect to the alloy weight) and tungsten powder with a particle size of 1 to 3 μm (iron in the powder) The chromium and nickel contents were each 0.05% by weight or less based on the weight of the alloy) and mixed well in a weight ratio shown in Table 1. The mixed powder was calcined for 5 hours at placed in a firing container shown in Table 1 hydrogen stream. The obtained fired body was put in a steel container and degassed, and then subjected to HIP treatment for 4 hours under the temperature conditions shown in Table 1 under a pressure of 1200 kgf / cm 2 . A test piece was cut out from the obtained alloy, and the content of iron, thermal conductivity, elongation of the alloy having mechanical properties, and drawing were measured. The results are shown in Table 1.
[Table 1]
Table 1 shows that in Examples 1-7 and Comparative Examples 1-8 (copper: tungsten = 35: 65), all of Examples 1-7 have excellent thermal conductivity and plastic workability. It should be noted that excellent heat conductivity is specifically about 150 W / (m · ° C) or more, and the success or failure of plastic working is a standard of elongation 4% or more and drawing 4% or more. Further, Examples 1, 3 and 4 show that the higher the firing temperature, the higher the elongation and drawing value of the obtained alloy, and the better the plastic workability.
On the other hand, in Comparative Examples 2 to 4 in which the HIP treatment was performed directly at 1083 ° C. or higher without firing as a preliminary treatment, iron contamination from the container progressed, and the iron content in the alloy increased significantly. The thermal conductivity is also lower than in each example. Moreover, also in Comparative Example 5 in which the firing was performed at 1083 ° C. or higher using a steel container, the progress of iron contamination and a decrease in thermal conductivity are observed.
[0019]
In Examples 8 and 9 and Comparative Examples 9 and 10 (copper: tungsten = 50: 50) in which the HIP treatment temperature is constant, the plastic workability changes rapidly with the firing temperature near the melting point of copper (1083 ° C.). You can see that That is, in Examples 8 and 9 where firing was performed at 1083 ° C. or higher, very good plastic workability was shown, but in Comparative Examples 9 and 10 fired at temperatures below that, plastic workability was inferior. .
This tendency is also observed in the case of the above (copper: tungsten = 35: 65).
[0020]
In Examples 10 and 11 and Comparative Examples 11 and 12 (copper: tungsten = 15: 85), it can be seen that Comparative Example 12, which was fired below the melting point of copper, is inferior in plastic workability. In addition, as in Comparative Example 5, Comparative Example 11 in which firing was performed at a temperature equal to or higher than the melting point of copper using a steel container showed the progress of iron contamination and low thermal conductivity.
[0021]
Throughout, it can be seen that the copper-tungsten alloy is more excellent in plastic workability and thermal conductivity as the copper content is higher under the same manufacturing conditions (Examples 1, 8, and 11). Further, in Examples using the production method of the present invention at any blending ratio, excellent plastic workability and thermal conductivity, specifically, elongation of 4% or more, drawing of 4% or more, and thermal conductivity of 150 W A copper-tungsten alloy having a // m · ° C. or higher was obtained.
[0022]
【The invention's effect】
The copper-tungsten alloy of the present invention is a copper-tungsten alloy produced by a powder sintering method, and its mechanical properties include elongation of 4% or more, drawing of 4% or more, and thermal conductivity of 150 W / ( m · ° C.) or more, it is excellent in plastic workability and has high thermal conductivity, so that it can be suitably used for an electrode for electrical discharge machining, a contact material, a heat transfer material, and the like.
[0023]
The method for producing a copper-tungsten alloy of the present invention is a method for producing a copper-tungsten alloy in which a mixed powder obtained by mixing copper powder and tungsten powder at a predetermined ratio is hot-pressurized and sintered. A pretreatment step of storing the mixed powder in a non-ferrous firing container, or gripping the green compact obtained by pressing the mixed powder with a non-ferrous jig and firing at 1083 ° C. or more and less than 1400 ° C .; And the step of storing the fired body obtained in the pretreatment step in a molding container and hot pressing and sintering at 950 ° C. or more and less than 1083 ° C., so that the HIP treatment is not performed at a temperature higher than the melting point of copper. A copper-tungsten alloy having the same plastic workability as that of the obtained alloy and also having high thermal conductivity can be obtained since no iron component is mixed during firing and HIP treatment.
[0024]
Since the molding container is a steel container, the cost of the HIP process can be reduced. Further, since the HIP treatment is always performed using a container, a copper-tungsten alloy having a blending ratio that cannot be manufactured by the capsule-free method can be manufactured.
Claims (9)
前記銅−タングステン合金はタングステン含量が５０〜８５重量％、鉄、ニッケル、クロムの含量がそれぞれ０．０５重量％以下、残部が銅および不可避的不純物からなり、銅とタングステンとの比率が同じ合金を 1083 ℃以上、1400 ℃未満で焼成した後に 950 ℃以上、1083 ℃未満で熱間加圧焼結することで、その機械的性質としての伸び、絞り、および熱伝導度が、 1083 ℃未満で焼成後に熱間加圧焼結した前記銅−タングステン合金よりも、それぞれ向上しており、その機械的性質は、伸びが 4 ％以上、絞りが 4 ％以上であり、また熱伝導度が 150 W/(m・℃)以上であることを特徴とする銅−タングステン合金。A copper-tungsten alloy by powder sintering,
The copper-tungsten alloy is an alloy having a tungsten content of 50 to 85% by weight, an iron, nickel and chromium content of 0.05% by weight or less, the balance being copper and inevitable impurities, and the same ratio of copper to tungsten. Is fired at 1083 ° C or more and less than 1400 ° C and then hot-pressed and sintered at 950 ° C or more and less than 1083 ° C, and its mechanical properties such as elongation, drawing, and thermal conductivity are less than 1083 ° C. The copper-tungsten alloys, which were hot-pressed and sintered after firing, each improved, and their mechanical properties were elongation of 4% or more, drawing of 4% or more, and thermal conductivity of 150 W. A copper-tungsten alloy characterized by being / (m · ° C) or more.
該製造方法は、前記混合粉を非鉄製の焼成用容器に収納し、または、前記混合粉をプレス加工した圧粉体を非鉄製の冶具で把持し 1083 ℃以上、1400 ℃未満で焼成する予備処理工程と、該予備処理工程で得た焼成体を成形用容器に収納して 950 ℃以上、1083 ℃未満で熱間加圧焼結する工程とを備えてなることを特徴とする銅−タングステン合金の製造方法。By hot pressing and sintering a mixed powder in which copper powder and tungsten powder are mixed at a predetermined ratio , the tungsten content is 50 to 85% by weight, and the contents of iron, nickel, and chromium are each 0.05% by weight or less, A method for producing a copper-tungsten alloy comprising a balance of copper and inevitable impurities, an elongation of 4% or more, a drawing of 4% or more, and a thermal conductivity of 150 W / (m · ° C) or more. ,
The production method includes storing the mixed powder in a non-ferrous baking container, or holding the pressed powder obtained by pressing the mixed powder with a non-ferrous jig and firing at 1083 ° C. or more and less than 1400 ° C. A copper-tungsten comprising: a treatment step; and a step of storing the fired body obtained in the preliminary treatment step in a molding container and hot pressing and sintering at 950 ° C. or more and less than 1083 ° C. Alloy manufacturing method.
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| JP5122856B2 (en) * | 2007-04-19 | 2013-01-16 | 光洋機械工業株式会社 | Discharge truing electrode, discharge truing device and grinding device |
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| JP5051168B2 (en) * | 2009-03-31 | 2012-10-17 | 日立ツール株式会社 | Nitride-dispersed Ti-Al target and method for producing the same |
| CN112530724B (en) * | 2020-10-19 | 2023-09-08 | 陕西斯瑞新材料股份有限公司 | Method for manufacturing electron beam welding copper-tungsten contact by using tungsten powder |
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