JP2004169064A - Copper-tungsten alloy, and method of producing the same - Google Patents
Copper-tungsten alloy, and method of producing the same Download PDFInfo
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Abstract
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、アルミニウム、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、銅粉の溶解が起こらず、溶解した銅粉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蒸気流中で 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]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a copper-tungsten alloy used as an electrode for electric 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 electrodes for electrical discharge machining, contact materials, and heat transfer materials are required to have excellent plastic workability and high thermal conductivity. The production method includes sintering a green compact obtained by pressing a tungsten simple powder, impregnating the sintered body with copper to obtain an alloy, and hot-pressing and sintering a mixed powder of copper and tungsten. Sintering (hereinafter referred to as “HIP processing”) to obtain a high-density alloy. In the HIP treatment, the powder material and the like can be densified without bias by diffusing the residual vacancies while applying pressure. Therefore, 1) excellent dimensional accuracy, 2) excellent material yield, and 3) irregular-shaped product It has advantages over the infiltration method, such as being suitable for manufacturing and 4) suitable for manufacturing composite materials and components.
[0003]
Representative examples of the HIP treatment include a capsule method using a molding container and a capsule-free method utilizing the fact that internal pores are closed during the HIP process without using a molding container. The capsule method is a method in which an object to be processed, such as a metal mixed powder, is sealed in a molding container (capsule) made of a material that is airtight with respect to a pressure medium gas, deaerated, and then subjected to HIP processing. This method can also increase the density of materials that cannot be densely sintered by ordinary sintering. Due to these advantages, the above-described encapsulation 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 the production of a copper-tungsten alloy using a mixed powder of copper powder and tungsten powder as a raw material, a capsule method using a high-purity silica glass capsule or the like and a capsule-free method without using a capsule are appropriately used depending on the amount of copper. In the case where the capsule-free method is used, a production method of performing preliminary sintering in order to close open holes is also disclosed (for example, see Patent Document 1).
[0005]
[Patent Document 1]
JP-A-5-271702 (Claims)
[0006]
[Problems to be solved by the invention]
However, the copper-tungsten alloy produced by the sintering method by the HIP process has a problem that the plastic workability varies greatly and a work result with good reproducibility cannot be obtained.
It is generally known that the higher the temperature at the time of the HIP treatment, the better the plastic workability is. However, in the process of producing a copper-tungsten alloy by the above-mentioned encapsulation method, when the HIP treatment temperature becomes high, steel At the contact surface between the forming container and the copper-tungsten alloy material, there is a problem that the iron component of the steel container is mixed into the alloy material and lowers the thermal conductivity of the copper-tungsten alloy. 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 the HIP processing, there is a problem that the practicality and mass productivity are poor and the processing cost is increased. In addition, the capsule-free method of performing the above-mentioned preliminary sintering uses the dissolution of copper to close the open holes on the surface and obtains the same effect as in the case of using capsules. If the compounding amount of the compound 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 address such a problem, a copper-tungsten alloy having excellent plastic workability and thermal conductivity, and an alloy having these excellent properties can be manufactured at low cost, and, An object of the present invention is to provide a method for producing a copper-tungsten alloy capable of alloying copper and tungsten at an arbitrary mixing ratio.
[0008]
[Means for Solving the Problems]
The copper-tungsten alloy of the present invention is a copper-tungsten alloy obtained by a powder sintering method, and has mechanical properties such as 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 (%)" which indicates the degree of plastic workability is a percentage obtained by dividing the length of the copper-tungsten alloy test piece at the time of fracture in the tensile test by the alloy length before the test. (%), And “drawing (%)” means the difference (reduced area) between the minimum cross-sectional area A and the initial cross-sectional area A 0 of the alloy flake broken in the tensile test, Percentage divided by zero . Further, “thermal conductivity W / (m · ° C.)” means that in a copper-tungsten alloy, when there is a temperature difference of 1 ° C. per 1 m, it is transmitted for 1 second through a 1 m 2 cross section of the alloy. Refers to the amount of heat.
[0010]
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-pressed and sintered. A pretreatment step of storing the mixed powder in a non-ferrous firing container, or holding a pressed compact of the mixed powder with a non-ferrous jig and firing at 1083 ° C. or more and less than 1400 ° C .; Storing the fired body obtained in the pre-treatment step in a molding container and subjecting it to hot pressure sintering at 950 ° C. or more and less than 1083 ° C.
[0011]
The molding container is a steel container. Further, the non-ferrous firing container and the jig are made of ceramic, graphite, or tungsten.
[0012]
In the method for producing a copper-tungsten alloy of the present invention, a mixed powder of copper powder and tungsten powder is stored in a non-ferrous container such as a ceramic container in advance before the HIP treatment, or in the case of a green compact, The same plastic processing as an alloy that was HIPed at a temperature equal to or higher than the melting point of copper by holding it with a jig made of iron and firing at a temperature equal to or higher than the melting point of copper, followed by HIPing at a temperature lower than the melting point of copper. A copper-tungsten alloy having excellent thermal conductivity can be obtained because the iron component is not mixed at the time of sintering and HIP processing while having the property.
Further, by performing the HIP process at a temperature lower than the melting point of copper, an inexpensive steel container can be used as a molding 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 compounding ratio that cannot be produced by the capsule-free method can be produced.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
The method for producing a copper-tungsten alloy of the present invention comprises: (A) a preliminary treatment step of previously firing a mixed powder of copper powder and tungsten powder in a predetermined temperature range; and (B) hot pressing the mixed powder in a predetermined temperature range. Sintering (HIP processing). Details of each step (A) and (B) will be described below.
(A) Pretreatment step As an alloy raw material, a mixed powder is prepared by mixing copper powder and tungsten powder each having a particle diameter of several μm to several tens μm. Since the HIP treatment after the preliminary treatment step is performed using a molding container, the amount of copper is not limited, and the mixing ratio of copper powder and tungsten powder can be arbitrarily set as long as an alloy can be formed. In addition, it is preferable to control the content of impurities such as iron, chromium and nickel in each powder in order to prevent a decrease in the thermal conductivity and plastic workability of the alloy. Specifically, each component is preferably set to 0.05% by weight or less based on the weight of the alloy.
The mixed powder, which is the above alloy material, is stored in a firing container and fired at 1083 ° C. or more and less than 1400 ° C. In the case of using a green compact obtained by pressing the mixed powder, a container is not necessary, and the green compact itself is gripped by a jig and fired in the above temperature range. The calcination is performed in a hydrogen stream for several hours. The firing container and the jig may be made of non-ferrous metal so that the mixing of iron components does not occur, and ceramic, graphite, tungsten, or the like can be suitably used. The reason why the upper limit of the temperature range is set to 1400 ° C. is that if the temperature is higher than this temperature, the evaporation of copper becomes so severe that it becomes impossible to operate practically.
[0014]
(B) HIP treatment step The fired body obtained in the preliminary treatment step is housed in a molding container and subjected to HIP treatment at 950 ° C or higher and lower than 1083 ° C. An arbitrary container made of silica glass, copper, aluminum, steel, or the like can be used as the container for molding. It is preferable to use a steel container because the processing cost can be reduced. The HIP process is performed for several hours under a pressure capable of obtaining a sufficient density. The reason why the lower limit of the HIP processing temperature is set to 950 ° C. is that the HIP processing does not proceed practically below this temperature.
[0015]
In the above (A) pretreatment step, the lower limit of the temperature range, 1083 ° C., is the melting point of copper. By baking the mixed powder (or its compact) at or above this temperature, the copper powder in the mixed powder melts and tungsten Adhesion with powder increases. This can potentially improve plastic workability before HIP processing. Next, in the (B) HIP treatment step, the fired body obtained in the preliminary treatment step is subjected to the HIP treatment at a temperature of less than 1083 ° C., so that the copper powder does not dissolve. Can prevent the iron component of the steel container from being mixed into the alloy material due to the contact, and can suppress the decrease in the thermal conductivity of the copper-tungsten alloy. As described above, the copper-tungsten alloy obtained by the production method has excellent plastic workability and high thermal conductivity, and thus can be suitably used as an electrode for electric 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 the HIP processing container in order to suppress the production cost of the copper-tungsten alloy, but conventionally, as described above, the use of a steel container has been In addition, there is a problem that the thermal conductivity is lowered, and a great cost is required to prevent the contact between the steel container and the copper-tungsten alloy during the HIP treatment. On the other hand, in the production method of the present invention, even when the alloy requires sufficient plastic workability, by pre-firing before the HIP processing, the HIP processing can be performed at a temperature lower than the melting point of copper. In addition, an inexpensive steel container can be used, and the production cost can be reduced. Also, since the HIP treatment 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 bottleneck in the case of the capsule-free method, It is possible to produce a copper-tungsten alloy of any mixing ratio.
[0017]
【Example】
Examples 1 to 11 and Comparative Examples 1 to 12
Copper powder having a particle size of 1 to 30 μm (the content of iron, chromium, and nickel in the powder is 0.05% by weight or less based on the weight of the alloy) and tungsten powder having a particle size of 1 to 3 μm (in the powder). (The content of iron, chromium, and nickel, respectively, is 0.05% by weight or less based on the weight of the alloy) in a weight ratio shown in Table 1 and well mixed. This mixed powder was placed in a firing container shown in Table 1 and fired in a steam flow for 5 hours. The obtained fired body was put in a steel container, deaerated, and then subjected to a HIP treatment under a pressure of 1200 kgf / cm 2 under the temperature conditions shown in Table 1 for 4 hours. A test piece was cut out from the obtained alloy, and the iron content, thermal conductivity, elongation of the alloy having mechanical properties, and drawing were measured. Table 1 shows the results.
[Table 1]
Table 1 shows that in Examples 1 to 7 and Comparative Examples 1 to 8 (copper: tungsten = 35: 65), all of Examples 1 to 7 have excellent thermal conductivity and plastic workability. In addition, the fact that the thermal conductivity is excellent is specifically about 150 W / (m · ° C.) or more, and the success or failure of the plastic working is 4% or more of elongation and 4% or more of drawing. In addition, it can be seen from Examples 1, 3 and 4 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 directly performed at 1083 ° C. or higher without performing the baking as a preliminary treatment, iron contamination from the container progressed, and the iron content in the alloy increased remarkably. The thermal conductivity is also lower than in each example. In Comparative Example 5 in which the firing was performed at 1083 ° C. or higher using a steel container, progress of iron contamination and a decrease in thermal conductivity were observed.
[0019]
In Examples 8 and 9 and Comparative Examples 9 and 10 (copper: tungsten = 50: 50) in which the HIP processing temperature was kept constant, the plastic workability rapidly changed around the sintering temperature near the melting point of copper (1083 ° C.). You can see that it is doing. That is, Examples 8 and 9 in which the calcination was performed at 1083 ° C. or higher exhibited extremely excellent plastic workability, whereas Comparative Examples 9 and 10 in which the calcination was performed at a temperature lower than 1083 ° C., were inferior in plastic workability. .
This tendency is similarly observed in the case of (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 in which firing was performed at a temperature equal to or lower than the melting point of copper was inferior in plastic workability. Similarly to Comparative Example 5, Comparative Example 11 in which the steel was fired at a temperature equal to or higher than the melting point of copper using a steel container showed progress of iron contamination and low thermal conductivity.
[0021]
Throughout, it can be seen that the higher the copper content in the copper-tungsten alloy under the same manufacturing conditions, the better the plastic workability and the thermal conductivity (Examples 1, 8, 11). Also, in any examples in which the production method of the present invention was used at any compounding 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 at least / (m · ° C.) was obtained.
[0022]
【The invention's effect】
The copper-tungsten alloy of the present invention is a copper-tungsten alloy obtained by a powder sintering method, and has mechanical properties such as elongation of 4% or more, drawing of 4% or more, and thermal conductivity of 150 W / ( m.degree. C.) or more, it is excellent in plastic workability and has high thermal conductivity, so that it can be suitably used as an electrode for electric 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 by hot-press sintering a mixed powder obtained by mixing a copper powder and a tungsten powder in a predetermined ratio. A pretreatment step of storing the mixed powder in a non-ferrous firing container, or holding a pressed compact of the mixed powder with a non-ferrous jig and firing at 1083 ° C. or more and less than 1400 ° C .; A step of storing the fired body obtained in the pretreatment step in a molding container and performing hot pressure sintering at 950 ° C. or more and less than 1083 ° C., so that the HIP treatment is performed at a temperature not lower than the melting point of copper. It is possible to obtain a copper-tungsten alloy having the same plastic workability as that of the alloy obtained, and also having high thermal conductivity because no iron component is mixed during firing and HIP processing.
[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 compounding ratio that cannot be produced by the capsule-free method can be produced.
Claims (4)
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。A method for producing a copper-tungsten alloy, which comprises hot-press sintering a mixed powder obtained by mixing copper powder and tungsten powder at a predetermined ratio,
The manufacturing method includes the steps of storing the mixed powder in a non-ferrous firing container, or holding a pressed compact of the mixed powder with a non-ferrous jig and firing at 1083 ° C. or higher and lower than 1400 ° C. A copper-tungsten process comprising: a treatment step; and a step of storing the fired body obtained in the pretreatment step in a molding container and hot-press sintering at 950 ° C. or more and less than 1083 ° C. Alloy manufacturing method.
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Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
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| EP1443546A2 (en) * | 2003-01-28 | 2004-08-04 | Hitachi Ltd. | Working method of metal material and semiconductor apparatus fabricated by the method |
| JP2006002188A (en) * | 2004-06-15 | 2006-01-05 | Yasushi Watanabe | Copper-based material and manufacturing method therefor |
| JP2008264919A (en) * | 2007-04-19 | 2008-11-06 | Koyo Mach Ind Co Ltd | Discharge truing electrode, discharge truing device, and grinding device |
| JP2009102725A (en) * | 2007-10-25 | 2009-05-14 | Fuji Dies Kk | Free cutting copper-tungsten alloy |
| JP2010236060A (en) * | 2009-03-31 | 2010-10-21 | Hitachi Tool Engineering Ltd | Nitride dispersion ti-al based target and method for producing the same |
| CN112530724A (en) * | 2020-10-19 | 2021-03-19 | 陕西斯瑞新材料股份有限公司 | Method for manufacturing electron beam welding copper-tungsten contact piece by using tungsten powder |
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Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
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| EP1443546A2 (en) * | 2003-01-28 | 2004-08-04 | Hitachi Ltd. | Working method of metal material and semiconductor apparatus fabricated by the method |
| EP1443546A3 (en) * | 2003-01-28 | 2009-05-06 | Hitachi Ltd. | Working method of metal material and semiconductor apparatus fabricated by the method |
| JP2006002188A (en) * | 2004-06-15 | 2006-01-05 | Yasushi Watanabe | Copper-based material and manufacturing method therefor |
| JP4508736B2 (en) * | 2004-06-15 | 2010-07-21 | 靖 渡辺 | Copper-based material and method for producing the same |
| JP2008264919A (en) * | 2007-04-19 | 2008-11-06 | Koyo Mach Ind Co Ltd | Discharge truing electrode, discharge truing device, and grinding device |
| JP2009102725A (en) * | 2007-10-25 | 2009-05-14 | Fuji Dies Kk | Free cutting copper-tungsten alloy |
| JP2010236060A (en) * | 2009-03-31 | 2010-10-21 | Hitachi Tool Engineering Ltd | Nitride dispersion ti-al based target and method for producing the same |
| CN112530724A (en) * | 2020-10-19 | 2021-03-19 | 陕西斯瑞新材料股份有限公司 | Method for manufacturing electron beam welding copper-tungsten contact piece by using tungsten powder |
| 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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