JP2004098111A - Manufacturing method for semi-molten metal and metal workpiece with fine spheroidized grain structure - Google Patents
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【０００１】
【発明の属する技術分野】
本発明は、半凝固金属等の製造方法に関するものであり、更に詳しくは、金属に高エネルギー振動力を付与して金属組織を球状化する方法、及び当該球状化方法を用いて、半溶融状態での鍛造、圧延、押出、加圧成形等の加工に供する微細球状化された組織を有する金属素材及びその成形品を製造する方法に関するものである。
【０００２】
【従来の技術】
一般に、半溶融加工に使用される金属素材は、インゴット素材の状態で初晶結晶が粒状で、かつ球状に近い粒子になっていることが必要である。この組織を得るために、従来の方法では、撹拌させながら金属材料を凝固させることにより、粒状の組織を得ていた。この撹拌方式としては、電磁撹拌、機械撹拌、又は単ロール撹拌が用いられている。これらのうち、電磁撹拌は、回転する磁界により溶融金属を撹拌する方法であり、円柱状の金属素材の円周方向に水平に撹拌する場合、円柱の軸方向に回転撹拌する場合、円柱の斜め軸方向に回転撹拌する場合の各方式が開発されている。しかし、このいずれの方式も、金属素材の凝固に伴う固相率の増加により、固相率が３０％を越えると粘性が急速に増加し、撹拌が十分に行えなくなり、粒状の組織を得ることが難しくなるという問題がある。このため、現在、市販されている、半溶融加工に供される金属素材は、いずれも完全な球状粒子ではなく、不定形の粒子を多数含んでおり、成形加工条件に大きな制約を受けると言う問題がある。
【０００３】
また、機械撹拌は、棒状の撹拌子を用いて半凝固金属を撹拌する方法であり、この方法の場合も固相率が約３０％を越えると、粘性が急速に増加し、固液共存体中に周囲の雰囲気が大量に巻き込まれ、使用に耐える金属素材が製造できなくなるという問題がある。更に、単ロール撹拌は、内部を水冷した回転ロールと固定板の間に挟んだ金属溶湯を回転ロールで撹拌しながら凝固させる方法であるが、回転ロールによる撹拌のために、凝固中の金属が均質に撹拌されないことから、均質な金属素材が得られないこと、及び固相率が大きくなると撹拌効果がなくなること、等の問題がある。
【０００４】
ここで、従来の方法を幾つか例示してみると、従来、半凝固金属を製造する方法として、例えば、非樹枝状初晶が金属融体中に分散した固体−液体金属混合物（半凝固金属）の製造方法が提案されている（特許文献１参照）。
また、非樹枝状初晶が金属融体中に分散した固体−液体金属混合物（半凝固金属）を連続的に製造するための方法が提案されている（特許文献２）。
更に、非樹枝状初晶が金属融体中に分散した固体−液体金属混合物（半凝固金属）を電磁誘導撹拌方式によって製造する方法が提案されている（特許文献３参照）。
【０００５】
【特許文献１】
特開平３−１７０６２９号公報
【特許文献２】
特開平３−１４２０４０号公報
【特許文献３】
特開平３−１７０６２９号公報
【０００６】
しかし、上記方法は、撹拌子の回転、撹拌用回転子の回転により、あるいは回転磁界によって溶融金属を回転流動させるものであり、金属素材の凝固に併う固相率の増加により、粒状の組織を得ることが難しくなるという問題を解消するには至っていない。
【０００７】
【発明が解決しようとする課題】
本発明は、このような従来技術における諸問題を抜本的に解決するためになされたものであって、電磁撹拌や機械撹拌等の撹拌操作を行うことなく、また、何ら他の元素、成分や物質等を添加することなく、凝固中の金属材料に、電場と磁場を印加するだけで、生成する固体結晶を球状化する方法を提供することを目的とするものである。また、本発明は、金属材料の成分や種類に依ることなく球状化を可能にする方法を提供することを目的とするものである。
更に、本発明は、上記方法を用いて、微細球状化した組織を有する金属素材を製造することを目的とするものである。
【０００８】
【課題を解決するための手段】
上記課題を解決するための本発明は、以下の技術的手段から構成される。
（１）電磁振動力や超音波振動力などの高エネルギー振動力を溶融金属に直接付与することにより、溶融金属中にキャビテーション（空孔）を生じさせ、その消滅時に発生する衝撃圧力で、生成してくる固体金属結晶を破砕分断すると共に、振動により金属組織を球状化する方法であって、
前記溶融金属に電流と磁場を同時に印加する、あるいは超音波を印加することにより、金属に高エネルギー振動力を付与することを特徴とする金属組織の球状化方法。
（２）電磁振動力や超音波振動力などの高エネルギー振動力を溶融金属に直接付与することにより、溶融金属中にキャビテーション（空孔）を生じさせ、その消滅時に発生する衝撃圧力で、生成してくる固体金属結晶を破砕分断すると共に、振動により金属組織を球状化する方法を用いて微細球状化した半凝固金属を製造する方法であって、
前記溶融金属に電流と磁場を同時に印加する、あるいは超音波を印加することにより、金属に高エネルギー振動力を付与することにより金属組織を微細球状化し、次いで、この状態から所定の冷却速度で冷却することを特徴とする半凝固金属の製造方法。
（３）金属組織を球状化するための電磁振動条件が、電流密度は０．３×１０６〜７×１０６Ａ／ｍ２、電流周波数は１０Ｈｚ〜１０００Ｈｚ、磁場強度は０．５〜１５テスラである、上記１又は２に記載の方法。
（４）金属材料が、純金属、合金、又は金属間化合物である、上記１又は２に記載の方法。
（５）電磁振動力や超音波振動力などの高エネルギー振動力を溶融金属に直接付与することにより、溶融金属中にキャビテーション（空孔）を生じさせ、その消滅時に発生する衝撃圧力で、生成してくる固体金属結晶を破砕分断すると共に、振動により金属組織を球状化する方法を用いて微細球状化した組織を有する金属素材を製造する方法であって、
前記溶融金属に電流と磁場を同時に印加する、あるいは超音波を印加することにより、金属に高エネルギー振動力を付与することにより金属組織を微細球状化し、次いで、この状態から所定の冷却速度で冷却を開始し、凝固させることを特徴とする金属素材の製造方法。
（６）金属組織を微細球状化する工程、及び所定の冷却速度で冷却、凝固させる工程を、連続的に行い、所定の断面形状を有する金属素材の連続体を製造する、上記５に記載の方法。
（７）円柱状、直方体状、又はスラブ状の断面形状を有する金属素材の連続体を製造する、上記６に記載の方法。
（８）上記６又は７に記載の方法により作製した金属素材を、半溶融状態での鍛造、圧延、押出、又は加圧成形に代表される加工手段に供して成形加工することを特徴とする上記金属素材の成形品の製造方法。
【０００９】
【発明の実施の形態】
次に、本発明について更に詳細に説明する。
本発明では、完全溶融状態、又は部分溶融状態（部分凝固も含む）の金属材料に対して、直流磁場を印加すると共に、交流電場を同時に印加することにより、電磁振動力を発生させる。完全溶融状態の金属材料では、その後、凝固を進行させる途中で磁場と電場を同時に印加する。この電磁振動力の作用により、液体金属中に共存している固体結晶が微細粒状に生成する。更に、この時の電磁振動条件として、特定の電磁振動条件を採用し、印加することにより、微細粒状結晶が球状化させることが可能となる。
【００１０】
金属組織を球状化するための電磁振動条件としては、電流密度は０．３×１０６〜７×１０６Ａ／ｍ２、電流周波数は１０Ｈｚ〜１０００Ｈｚ、磁場強度は０．５〜１５テスラ、が好適である。上記条件を採用することにより、金属組織を微細球状化することが可能となる。次に、本発明では、この状態から所定の冷却速度で冷却を開始し、半凝固金属を製造し、更に、完全に凝固完了するまで冷却を行い、微細球状化された組織を有する金属素材を製造する。これにより、高い固相率においても、高い割合で微細で、かつ均一に球状化された組織を有する金属素材を製造することが可能となる。
【００１１】
この時、半凝固金属及び金属素材の内部組織は、初晶結晶の球状化度と固相率で規定される。初晶結晶の球状化度は、電磁振動条件、すなわち、電流強度、電流周波数、磁場強度に依存する。また、初晶結晶の固相率は、電磁振動力を印加するプロセス部での冷却速度で規定される。冷却速度が大きい場合には、微細な球状粒子が得られ、冷却速度が小さい場合には、粗大な球状粒子が得られる。プロセスの冷却速度は、溶融金属材料の温度とプロセス部との温度差及びプロセス部とその直下の水冷急冷帯との距離により規定される。対象金属合金に対して、これらの諸条件を最適化することにより、種々の断面形状をもつ連続半凝固金属素材を製造することができる。
本発明では、上記方法における金属組織を微細球状化する工程、及び所定の冷却速度で冷却、凝固させる工程を連続的に行い、所定の断面形状を有する金属素材の連続体を製造することができる。また、この金属素材を、半溶融状態での鍛造、圧延、押出、加圧成形等の加工に供して二次加工することにより適宜の形状を有する金属素材成形品を製造することができる。
【００１２】
【実施例】
次に、実施例に基づいて本発明を具体的に説明するが、本発明は、以下の実施例によって何ら限定されるものではない。
実施例１
Ａｌ−７％Ｓｉ合金に対して、本発明のプロセスを適用した。セラミックス容器に挿入した合金試料を、超電導マグネットの磁場空間内の中央部に固定し、可動式の加熱炉により７００℃まで加熱溶解し、２分間等温保持し、試料の均質化を行った。その後、１０テスラの磁場強度を発生させると共に、６０Ｈｚで４．２４×１０６Ａ／ｍ２の交流電流を印加して電磁振動力を付与した。この状態から３０〜４０℃／ｓｅｃの冷却速度で冷却を開始し、半凝固金属を製造し、更に、完全に凝固完了するまで冷却を行った。得られた金属素材の組織を図１に示す。通常の凝固組織で見られる初晶のデンドライト組織と大きく異なり、初晶アルミニウムのデンドライト組織が顕著に球状化した粒子組織が得られた。類似の球状化組織は、この他の電磁振動条件、例えば、６０Ｈｚで２．８３×１０６Ａ／ｍ２の交流電流を印加した場合等にも確認された。
【００１３】
実施例２
ＡＺ９１Ｄマグネシウム合金に対して、本発明のプロセスを適用した。石英ガラス容器に挿入した合金試料を、常電導マグネットの磁場空間内の中央部に固定し、可動式の加熱炉により６５０℃まで加熱溶解し、２分間等温保持し、試料の均質化を行った。その後、１．６テスラの磁場強度を発生させると共に、１５０Ｈｚで１．４２×１０６Ａ／ｍ２の交流電流を試料両端の電極を介して印加し、電磁振動力を付与した。この状態から２℃／ｓｅｃの冷却速度で冷却を開始し、所定の時間電磁振動を付与し、半凝固金属を製造した後、更に、水冷（約１００℃／ｓｅｃ）による急冷を行った。得られた金属素材の組織を図２に示す。同じ冷却速度における通常の凝固組織で見られる初晶のデンドライト組織とは大きく異なり、初晶マグネシウムのデンドライト組織が球状化した粒子組織が得られた。
【００１４】
実施例３
灰鋳鉄に対して、本発明のプロセスを適用した。使用した灰鋳鉄は、砂型鋳造材と連続鋳造材であり、試料の組成を表１に示す。砂型鋳造材は亜共晶組成であり、連続鋳造材はほぼ共晶組成である。セラミックス容器に挿入した合金試料を超電導マグネットの磁場空間内の中央部に固定し、可動式の加熱炉により１３５０℃まで加熱溶解し、その温度で保持することにより試料の均質化を行った。その後、１０テスラの磁場を印加すると共に、２００Ｈｚで３．５４×１０６Ａ／ｍ２の交流電流を印加して電磁振動力を付与した。この状態から７℃／ｓｅｃの冷却速度で冷却を開始し、半凝固金属を製造し、更に、完全に凝固完了するまで冷却を行った。
【００１５】
【表１】
砂型鋳造材の灰鋳鉄に対して得られた金属素材の組織を図３に示す。従来の鋳造法と同程度の冷却速度における凝固組織では、オーステナイトの柱状デンドライトが発達した組織となるのに対して、初晶オーステナイトが顕著に球状化した粒子が得られた。類似の球状化組織は、この他の電磁振動条件、例えば、２００Ｈｚで４．９５×１０６Ａ／ｍ２の交流電流を印加した場合等にも確認された。また、連続鋳造材の灰鋳鉄についても、同様の電磁振動条件で類似の組織が得られた。
【００１７】
実施例４
Ａｌ−７％Ｓｉ合金、ＡＺ９１Ｄ合金、灰鋳鉄等のインゴット片を、本プロセス装置の導入部に挿入して、電磁振動印加部直前で完全溶解した。その溶解試料を、超電導マグネット内に移動させて、電磁振動力を印加した。ここで初晶結晶が微細球状化した試料を、そのプロセス部から下方に移動させ、直ちに凝固させて、金属素材とした。この金属素材は、プロセス部内の容器の形状により、円柱状、直方体状、スラブ状等種々の断面形状を有す連続体の金属素材となった。
【００１８】
実施例５
ＡＣ４ＣＨ等のアルミニウム合金に対して、本発明のプロセスを適用することにより製造された金属素材を、半溶融状態に再加熱し、所定の金型により加圧成形し、自動車部品を成形した。その結果、従来の半凝固金属材料素材を使用した場合に較べて、金型内の流動性が大きく改善された。また、初晶結晶が球状化しているため、高固相率においても加圧成形による良好な金型充填性が得られた。その結果、ダイカスト成形品と同程度の複雑形状部品の成形加工が可能となった。この場合、ダイカスト製品とは異なり、半凝固金属を充填するため、内部欠陥が著しく減少し、熱処理の可能な製品の製造が可能となった。
【００１９】
実施例６
ＡＺ９１Ｄ等のマグネシウム合金に対して、本発明のプロセスを適用することにより製造された金属素材を、半溶融状態に再加熱し、金型により加圧成形し、情報通信機器、音響・画像機器部品を成形した。その結果、従来のチクソモールディングプロセスによる半凝固金属材料素材に較べて、金型内の流動性が大きく改善された。また、薄肉製品においても湯廻り不良、ブローホール等の内部欠陥が著しく減少した。
【００２０】
実施例７
ＡＣ８Ａ合金等のアルミニウム合金に対して、本発明のプロセスを適用することにより製造された金属素材を、半溶融状態に再加熱し、金型により加圧成形し、家電製品におけるクーラー用コンプレッサー部品を成形した。その結果、従来の半凝固金属材料素材を使用した場合に較べて、金型内の流動性が大きく改善された。この場合にも、高固相率の半凝固金属材料素材を加圧成形することにより、内部欠陥を著しく減少することが可能となった。
【００２１】
【発明の効果】
以上詳述したように、本発明は、金属に高エネルギー振動力を付与することにより金属組織を微細球状化する方法、及び当該方法を用いて微細球状化した組織を有する金属素材を製造する方法に係るものであり、本発明により、高い固相率においても高い球状化率を有する金属素材を製造することができる。本発明によれば、例えば、自動車の足廻り部品やエンジン廻り部品やコンプレッサー部品、家電製品におけるモーター周囲部品や情報通信機器・音響機器・画像機器のケースやＣＲＴケース、小型軽量機械部品等を製造するための、半溶融状態での鍛造、圧延、押出、加圧成形等の半溶融加工及び半溶融成形加工に必要な金属素材を工業的規模で効率よく生産することが可能となる。
【図面の簡単な説明】
【図１】Ａｌ−７％Ｓｉ合金の電磁振動付与による、初晶アルミニウム結晶の微細球状化された組織を示す。
【図２】ＡＺ９１Ｄ合金の電磁振動付与による、初晶マグネシウム結晶の微細球状化された組織を示す。
【図３】砂型鋳造した灰鋳鉄の電磁振動付与による、初晶オーステナイト結晶の微細球状化された組織を示す。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for producing semi-solid metal and the like, and more specifically, a method for imparting high-energy vibrational force to metal to spheroidize a metal structure, and a semi-molten state using the spheroidization method. TECHNICAL FIELD The present invention relates to a metal material having a micro-spheroidized structure to be subjected to processing such as forging, rolling, extrusion, and pressure forming, and a method for producing a molded product thereof.
[0002]
[Prior art]
Generally, in a metal material used for semi-solid processing, it is necessary that the primary crystal is granular and nearly spherical in the state of an ingot material. In order to obtain this structure, in a conventional method, a granular structure is obtained by solidifying a metal material while stirring. As this stirring method, electromagnetic stirring, mechanical stirring, or single-roll stirring is used. Among these, electromagnetic stirring is a method of stirring molten metal by a rotating magnetic field, and when stirring horizontally in the circumferential direction of a cylindrical metal material, when rotating and stirring in the axial direction of the cylinder, or obliquely Various methods have been developed for rotating and stirring in the axial direction. However, in any of these methods, the viscosity increases rapidly when the solid phase ratio exceeds 30% due to an increase in the solid phase ratio due to solidification of the metal material, so that stirring cannot be performed sufficiently and a granular structure is obtained. There is a problem that becomes difficult. For this reason, it is said that the metal materials that are currently commercially available and are subjected to semi-solid processing are not completely spherical particles, but contain a large number of irregular-shaped particles, and are greatly restricted by molding processing conditions. There's a problem.
[0003]
In addition, mechanical stirring is a method of stirring semi-solid metal using a rod-shaped stirrer. In this method, when the solid phase ratio exceeds about 30%, the viscosity rapidly increases, and the solid-liquid coexistence There is a problem that a large amount of the surrounding atmosphere is caught in the inside, and a metal material that can be used cannot be manufactured. Further, single-roll stirring is a method of solidifying a molten metal sandwiched between a rotating roll and a fixed plate, which are internally cooled with water, while stirring the molten metal with the rotating roll. Since there is no agitation, there are problems that a homogeneous metal material cannot be obtained, and that the agitation effect is lost when the solid fraction increases.
[0004]
Here, some conventional methods are exemplified. Conventionally, as a method for producing a semi-solid metal, for example, a solid-liquid metal mixture in which non-dendritic primary crystals are dispersed in a metal melt (a semi-solid metal) ) Has been proposed (see Patent Document 1).
Further, a method for continuously producing a solid-liquid metal mixture (semi-solid metal) in which non-dendritic primary crystals are dispersed in a metal melt has been proposed (Patent Document 2).
Furthermore, there has been proposed a method for producing a solid-liquid metal mixture (semi-solid metal) in which non-dendritic primary crystals are dispersed in a metal melt by an electromagnetic induction stirring method (see Patent Document 3).
[0005]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 3-170629 [Patent Document 2]
JP-A-3-142040 [Patent Document 3]
JP-A-3-170629
However, the above method is to rotate the molten metal by rotation of the stirrer, rotation of the stirring rotor, or by a rotating magnetic field. It has not been possible to solve the problem that it will be difficult to obtain.
[0007]
[Problems to be solved by the invention]
The present invention has been made in order to drastically solve such problems in the prior art, without performing a stirring operation such as electromagnetic stirring or mechanical stirring, and without any other elements, components or It is an object of the present invention to provide a method of spheroidizing a solid crystal to be generated by applying an electric field and a magnetic field to a solidifying metal material without adding a substance or the like. Another object of the present invention is to provide a method that enables spheroidization regardless of the components and types of metal materials.
A further object of the present invention is to produce a metal material having a micro-spheroidized structure using the above method.
[0008]
[Means for Solving the Problems]
The present invention for solving the above-mentioned problems includes the following technical means.
(1) Cavitation (vacancies) is generated in the molten metal by directly applying a high-energy vibration force, such as an electromagnetic vibration force or an ultrasonic vibration force, to the molten metal. A method of crushing and dividing the solid metal crystal that comes up, and spheroidizing the metal structure by vibration,
A method for spheroidizing a metal structure, comprising applying a high-energy oscillating force to a metal by simultaneously applying a current and a magnetic field to the molten metal, or by applying ultrasonic waves.
(2) Cavitation (vacancies) is generated in the molten metal by directly applying a high-energy vibration force, such as an electromagnetic vibration force or an ultrasonic vibration force, to the molten metal. A method of producing a semi-solid metal that has been finely spheroidized using a method of spheroidizing a metal structure by vibration while crushing and dividing the solid metal crystal that comes,
By applying a current and a magnetic field to the molten metal at the same time, or by applying an ultrasonic wave, a high-energy oscillating force is applied to the metal to make the metal structure finely spherical, and then cooled at a predetermined cooling rate from this state. A method for producing a semi-solid metal.
(3) Electromagnetic vibration conditions for spheroidizing the metal structure include a current density of 0.3 × 10 6 to 7 × 10 6 A / m 2 , a current frequency of 10 Hz to 1000 Hz, and a magnetic field strength of 0.5 to 15 3. The method according to 1 or 2, wherein the method is Tesla.
(4) The method according to the above (1) or (2), wherein the metal material is a pure metal, an alloy, or an intermetallic compound.
(5) Cavitation (vacancies) is generated in the molten metal by directly applying a high-energy vibration force such as an electromagnetic vibration force or an ultrasonic vibration force to the molten metal, and is generated by an impact pressure generated when the cavitation disappears. A method of manufacturing a metal material having a micro-spheroidized structure by using a method of spherifying a metal structure by vibration while crushing and dividing the solid metal crystal that is to be obtained,
By applying a current and a magnetic field to the molten metal at the same time, or by applying an ultrasonic wave, a high-energy oscillating force is applied to the metal to make the metal structure finely spherical, and then cooled at a predetermined cooling rate from this state. Starting and solidifying the metal material.
(6) The method according to the above (5), wherein the step of finely spheroidizing the metal structure and the step of cooling and solidifying at a predetermined cooling rate are continuously performed to produce a continuous body of a metal material having a predetermined cross-sectional shape. Method.
(7) The method according to the above (6), wherein a continuous body of a metal material having a columnar, rectangular parallelepiped, or slab-shaped cross section is manufactured.
(8) The metal material produced by the method described in 6 or 7 above is subjected to forming by subjecting it to processing means represented by forging, rolling, extrusion, or pressure forming in a semi-molten state. A method for producing a molded product of the above metal material.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, the present invention will be described in more detail.
In the present invention, an electromagnetic vibration force is generated by applying a DC magnetic field and simultaneously applying an AC electric field to a metal material in a completely melted state or a partially melted state (including partially solidified state). In the case of a completely molten metal material, a magnetic field and an electric field are simultaneously applied during the progress of solidification. By the action of this electromagnetic vibration force, solid crystals coexisting in the liquid metal are formed in fine particles. Further, by adopting and applying a specific electromagnetic vibration condition as the electromagnetic vibration condition at this time, the fine granular crystal can be made spherical.
[0010]
Electromagnetic vibration conditions for spheroidizing the metal structure include a current density of 0.3 × 10 6 to 7 × 10 6 A / m 2 , a current frequency of 10 Hz to 1000 Hz, a magnetic field strength of 0.5 to 15 Tesla, Is preferred. By adopting the above conditions, the metal structure can be made into a fine sphere. Next, in the present invention, cooling is started at a predetermined cooling rate from this state, a semi-solid metal is produced, and further cooled until complete solidification is completed, and a metal material having a micro-spheroidized structure is produced. To manufacture. Thereby, even at a high solid phase ratio, it is possible to manufacture a metal material having a fine and uniformly spherical structure at a high ratio.
[0011]
At this time, the internal structure of the semi-solid metal and the metal material is defined by the degree of spheroidization of the primary crystal and the solid fraction. The degree of spheroidization of the primary crystal depends on electromagnetic vibration conditions, that is, current intensity, current frequency, and magnetic field intensity. In addition, the solid phase ratio of the primary crystal is defined by a cooling rate in a process section to which an electromagnetic vibration force is applied. When the cooling rate is high, fine spherical particles are obtained, and when the cooling rate is low, coarse spherical particles are obtained. The cooling rate of the process is defined by the temperature difference between the temperature of the molten metal material and the process section and the distance between the process section and the water-cooled quenching zone immediately below the process section. By optimizing these conditions for the target metal alloy, continuous semi-solid metal materials having various cross-sectional shapes can be manufactured.
In the present invention, the step of finely spheroidizing the metal structure and the step of cooling and solidifying at a predetermined cooling rate in the above method can be continuously performed to produce a continuous body of a metal material having a predetermined cross-sectional shape. . Further, by subjecting the metal material to a process such as forging, rolling, extrusion, and pressure forming in a semi-molten state and then performing a secondary process, a metal material molded article having an appropriate shape can be manufactured.
[0012]
【Example】
Next, the present invention will be specifically described based on examples, but the present invention is not limited to the following examples.
Example 1
The process of the present invention was applied to an Al-7% Si alloy. The alloy sample inserted into the ceramic container was fixed to the central portion of the superconducting magnet in the magnetic field space, heated and melted to 700 ° C. in a movable heating furnace, and kept at a constant temperature for 2 minutes to homogenize the sample. Thereafter, a magnetic field strength of 10 Tesla was generated, and an alternating current of 4.24 × 10 6 A / m 2 at 60 Hz was applied to apply an electromagnetic vibration force. From this state, cooling was started at a cooling rate of 30 to 40 ° C./sec to produce a semi-solid metal, and further cooled until complete solidification was completed. FIG. 1 shows the structure of the obtained metal material. The primary crystal dendrite structure was significantly different from the primary crystal dendrite structure seen in the normal solidification structure, and a particle structure in which the dendrite structure of the primary crystal aluminum was remarkably spheroidized was obtained. A similar spheroidized structure was also confirmed under other electromagnetic vibration conditions, for example, when an alternating current of 2.83 × 10 6 A / m 2 was applied at 60 Hz.
[0013]
Example 2
The process of the present invention was applied to AZ91D magnesium alloy. The alloy sample inserted in the quartz glass container was fixed to the center of the normal conducting magnet in the magnetic field space, heated and melted to 650 ° C. in a movable heating furnace, and kept at a constant temperature for 2 minutes to homogenize the sample. . Thereafter, a magnetic field strength of 1.6 Tesla was generated, and an alternating current of 1.42 × 10 6 A / m 2 at 150 Hz was applied through electrodes at both ends of the sample to apply an electromagnetic vibration force. From this state, cooling was started at a cooling rate of 2 ° C./sec, electromagnetic vibration was applied for a predetermined time to produce a semi-solid metal, and then rapid cooling by water cooling (about 100 ° C./sec) was performed. FIG. 2 shows the structure of the obtained metal material. The primary crystal dendrite structure was significantly different from the primary crystal dendrite structure observed in the normal solidification structure at the same cooling rate, and a particle structure in which the primary crystal magnesium dendrite structure was spheroidized was obtained.
[0014]
Example 3
The process of the present invention was applied to gray cast iron. The ash cast iron used was a sand casting material and a continuous casting material, and the composition of the sample is shown in Table 1. The sand casting has a hypoeutectic composition, and the continuous casting has a nearly eutectic composition. The alloy sample inserted into the ceramic container was fixed to the center of the superconducting magnet in the magnetic field space, melted and heated to 1350 ° C. in a movable heating furnace, and kept at that temperature to homogenize the sample. Thereafter, while applying a magnetic field of 10 Tesla, an alternating current of 3.54 × 10 6 A / m 2 was applied at 200 Hz to apply an electromagnetic vibration force. From this state, cooling was started at a cooling rate of 7 ° C./sec to produce a semi-solid metal, and further cooled until complete solidification was completed.
[0015]
[Table 1]
FIG. 3 shows the structure of the metal material obtained for the ash cast iron of the sand casting material. In the solidification structure at the same cooling rate as that of the conventional casting method, a structure in which columnar dendrites of austenite were developed was obtained, while particles in which primary austenite was remarkably spheroidized were obtained. A similar spheroidized structure was also confirmed under other electromagnetic vibration conditions, for example, when an alternating current of 4.95 × 10 6 A / m 2 was applied at 200 Hz. In addition, a similar structure was obtained for the ash cast iron as a continuous cast material under the same electromagnetic vibration conditions.
[0017]
Example 4
An ingot piece of Al-7% Si alloy, AZ91D alloy, ash cast iron, or the like was inserted into the introduction section of the present process apparatus, and was completely melted immediately before the electromagnetic vibration application section. The dissolved sample was moved into a superconducting magnet, and an electromagnetic vibration force was applied. Here, the sample in which the primary crystal was finely spheroidized was moved downward from the process part and immediately solidified to obtain a metal material. This metal material was a continuous metal material having various cross-sectional shapes such as a columnar shape, a rectangular parallelepiped shape, and a slab shape, depending on the shape of the container in the process section.
[0018]
Example 5
A metal material produced by applying the process of the present invention to an aluminum alloy such as AC4CH was reheated to a semi-molten state, pressure-formed with a predetermined mold, and an automobile part was formed. As a result, the fluidity in the mold was greatly improved as compared with the case where the conventional semi-solid metal material was used. In addition, since the primary crystals were spherical, favorable mold filling properties by pressure molding were obtained even at a high solid phase ratio. As a result, it has become possible to form a complex-shaped part of the same size as a die-cast molded product. In this case, unlike a die-cast product, since a semi-solid metal is filled, internal defects are significantly reduced, and a product that can be heat-treated can be manufactured.
[0019]
Example 6
A metal material manufactured by applying the process of the present invention to a magnesium alloy such as AZ91D is reheated to a semi-molten state, pressed and formed by a metal mold, and is used for information communication equipment, audio / video equipment parts. Was molded. As a result, the fluidity in the mold was greatly improved as compared with the semi-solid metal material obtained by the conventional thixomolding process. In addition, in the case of thin-walled products, internal defects such as poor running water and blowholes were significantly reduced.
[0020]
Example 7
A metal material produced by applying the process of the present invention to an aluminum alloy such as an AC8A alloy is reheated to a semi-molten state, pressed by a metal mold, and used as a compressor component for a cooler in a home appliance. Molded. As a result, the fluidity in the mold was greatly improved as compared with the case where the conventional semi-solid metal material was used. Also in this case, it is possible to significantly reduce internal defects by press-molding a semi-solid metal material having a high solid fraction.
[0021]
【The invention's effect】
As described in detail above, the present invention provides a method of finely spheroidizing a metal structure by applying a high-energy oscillating force to a metal, and a method of manufacturing a metal material having a finely spheroidized structure using the method. According to the present invention, a metal material having a high spheroidization ratio even at a high solid phase ratio can be produced. According to the present invention, for example, parts for automobiles, parts for engines, parts for compressors, parts for motors in home appliances, cases for information communication equipment, audio equipment, imaging equipment, CRT cases, small and light mechanical parts, etc. are manufactured. For this purpose, semi-solid processing such as forging, rolling, extrusion and pressure molding in a semi-molten state and metal materials required for the semi-solid molding can be efficiently produced on an industrial scale.
[Brief description of the drawings]
FIG. 1 shows a micro-spheroidized structure of primary aluminum crystals by applying electromagnetic vibration of an Al-7% Si alloy.
FIG. 2 shows a micro-spheroidized structure of primary magnesium crystal by application of electromagnetic vibration of an AZ91D alloy.
FIG. 3 shows a micro-spheroidized structure of primary austenite crystal obtained by applying electromagnetic vibration to sand cast ash cast iron.
Claims (8)
前記溶融金属に電流と磁場を同時に印加する、あるいは超音波を印加することにより、金属に高エネルギー振動力を付与することを特徴とする金属組織の球状化方法。Cavitation (vacancies) is generated in the molten metal by directly applying high-energy vibrational force such as electromagnetic vibrational force or ultrasonic vibrational force to the molten metal, and the cavitation is generated by the impact pressure generated at the time of its disappearance. A method of crushing and cutting a solid metal crystal and spheroidizing a metal structure by vibration,
A method for spheroidizing a metal structure, comprising applying a high-energy oscillating force to a metal by simultaneously applying a current and a magnetic field to the molten metal, or by applying ultrasonic waves.
前記溶融金属に電流と磁場を同時に印加する、あるいは超音波を印加することにより、金属に高エネルギー振動力を付与することにより金属組織を微細球状化し、次いで、この状態から所定の冷却速度で冷却することを特徴とする半凝固金属の製造方法。Cavitation (vacancies) is generated in the molten metal by directly applying high-energy vibrational force such as electromagnetic vibrational force or ultrasonic vibrational force to the molten metal, and the cavitation is generated by the impact pressure generated at the time of its disappearance. A method for producing a semi-solid metal having a fine spherical shape by crushing and dividing a solid metal crystal and using a method of spheroidizing a metal structure by vibration,
By applying a current and a magnetic field to the molten metal at the same time, or by applying an ultrasonic wave, a high-energy oscillating force is applied to the metal to make the metal structure finely spherical, and then cooled at a predetermined cooling rate from this state. A method for producing a semi-solid metal.
前記溶融金属に電流と磁場を同時に印加する、あるいは超音波を印加することにより、金属に高エネルギー振動力を付与することにより金属組織を微細球状化し、次いで、この状態から所定の冷却速度で冷却を開始し、凝固させることを特徴とする金属素材の製造方法。Cavitation (vacancies) is generated in the molten metal by directly applying high-energy vibrational force such as electromagnetic vibrational force or ultrasonic vibrational force to the molten metal, and the cavitation is generated by the impact pressure generated at the time of its disappearance. A method for producing a metal material having a micro-spheroidized structure by using a method of crushing and dividing a solid metal crystal and spheroidizing a metal structure by vibration,
By applying a current and a magnetic field to the molten metal at the same time, or by applying an ultrasonic wave, a high-energy oscillating force is applied to the metal to make the metal structure finely spherical, and then cooled at a predetermined cooling rate from this state. Starting and solidifying the metal material.
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| JP2007216239A (en) * | 2006-02-14 | 2007-08-30 | National Institute For Materials Science | Casting method |
| JP2007326149A (en) * | 2006-05-12 | 2007-12-20 | Chiba Inst Of Technology | Method for producing composite body of carbon nanomaterial and metallic material |
| JP2009195911A (en) * | 2008-02-19 | 2009-09-03 | Sintokogio Ltd | Method for casting aluminum alloy casting product and apparatus therefor |
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| JP2007216239A (en) * | 2006-02-14 | 2007-08-30 | National Institute For Materials Science | Casting method |
| JP2007326149A (en) * | 2006-05-12 | 2007-12-20 | Chiba Inst Of Technology | Method for producing composite body of carbon nanomaterial and metallic material |
| JP4526550B2 (en) * | 2006-05-12 | 2010-08-18 | 学校法人千葉工業大学 | Method for producing composite of carbon nanomaterial and metal material |
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