JP4261705B2

JP4261705B2 - Semi-molten forging of dissimilar metals

Info

Publication number: JP4261705B2
Application number: JP30173099A
Authority: JP
Inventors: 修加田; 正弘戸田; 武司三木
Original assignee: Nippon Steel Corp
Current assignee: Nippon Steel Corp
Priority date: 1999-10-22
Filing date: 1999-10-22
Publication date: 2009-04-30
Anticipated expiration: 2019-10-22
Also published as: JP2001121234A

Description

【０００１】
【発明の属する技術分野】
本発明は異種金属からなる部品の製造法、特に複雑な形状を有する部品の製造方法に関するものである。
【０００２】
【従来の技術】
これまで、異種金属同士を接合，一体化する方法は、固相温度域、液相温度域あるいは固液共存温度域での接合法などが開示されている。例えば固相温度域では特開昭５６−１２８６８８号公報において、接合する金属表面に微細な凹凸を形成した後、熱間静水圧処理を行い接合面強度を高める方法が開示されている。また、液相温度域では特開昭６３−２９５０７７号公報において、接合する金属の一方の表面を溶融させた後、もう一方の金属を押しつけ冷却する方法が開示されている。さらに固液共存温度域では、文献（塑性加工連合講演会講演論文集ＶＯＬ．４８ｔｈＰＡＧＥ．４０７‐４０８１９９７）において、接合する一方の金属を固液共存温度域に加熱し、もう一方の金属を挿入後冷却する方法が開示されている。
【０００３】
【発明が解決すべき課題】
しかしながら、特開昭５６−１２８６８８号公報及び特開昭６３−２９５０７７号公報では、複雑形状部品を異種金属を接合，一体化して製造する場合、予めそれぞれの金属体を最終形状を構成する形状に仕上げておく必要があり、その後異種金属を接合する方法を採らざるを得ず、製造コストの上昇につながる。また、文献ではフィン付き部品等ある特定形状の部品においては低コストでの製造が可能であるが、積極的に部品形状を創製するものではなく、他形状の部品に適用することは困難であり、また接合強度も不十分である。
本発明は、上記の点に鑑みてなされたもので、極めて単純な形状である２種類以上の異種金属素材を用いて、異種金属からなる複雑形状部品を歩留まり良くかつ少数回の鍛造工程で成形し、しかも接合面の強度を向上させることを目的とするものである。
【０００４】
【課題を解決するための手段】
即ち本発明の要旨とするところは、
１）固相率ｆＳが０．３以上０．９未満となる温度域Ｔ_{０．３−０．９}の重複しない高融点金属と低融点金属からなる鍛造部品の製造方法において、それぞれの金属に対して固相率ｆＳが０．３以上０．９未満となる温度域Ｔ_{０．３−０．９}の重複する単数の金属をインサート材として用い、高融点金属とインサート材を、それぞれの固相率ｆＳが０．３以上０．９未満となる温度域Ｔ_{０．３−０．９}の重複する温度に加熱、鍛造型内に挿入、鍛造して中間製品を製造した後、前記中間製品と低融点金属を、インサート材と低融点金属の固相率ｆＳが０．３以上０．９未満となる温度Ｔ_{０．３−０．９}の重複する温度に加熱、鍛造型内に挿入、鍛造して、一体化することを特徴とする半溶融鍛造方法
２）固相率ｆＳが０．３以上０．９未満となる温度域Ｔ_{０．３−０．９}の重複しない高融点金属と低融点金属からなる鍛造部品の製造方法において、それぞれの金属に対して固相率ｆＳが０．３以上０．９未満となる温度域Ｔ_{０．３−０．９}が重複する融点の異なる複数のインサート材を用い、高融点金属材料と高融点インサート材を、それぞれの固相率ｆＳが０．３以上０．９未満となる温度域Ｔ_{０．３−０．９}の重複する温度に加熱、鍛造型内に挿入、鍛造して第1中間製品を製造し、前記第1中間製品と低融点インサート材を、高融点インサート材と低融点インサート材の固相率ｆＳが０．３以上０．９未満となる温度域Ｔ_{０．３−０．９}の重複する温度に加熱、鍛造型内に挿入、鍛造し第2中間製品を製造した後、前記第2中間製品と低融点金属を、低融点インサート材と低融点金属の固相率ｆＳが０．３以上０．９未満となる温度域Ｔ_{０．３−０．９}の重複する温度に加熱、鍛造型内に挿入、鍛造して一体化することを特徴とする半溶融鍛造方法
３）高融点金属とインサート材及び中間製品と低融点金属の少なくとも１組の形状が異形状であることを特徴とする上記１）記載の半溶融鍛造方法
４）高融点金属とインサート材及び中間製品と低融点金属の少なくとも１組の形状が同径であることを特徴とする上記１）記載の半溶融鍛造方法
５）高融点金属とインサート材及び中間製品と低融点金属の少なくとも１組の形状が円筒状及び円柱状であり、円筒内径と円柱外径が実質的に同径であることを特徴とする上記１）記載の半溶融鍛造方法
６）高融点金属と高融点インサート材、第１中間製品と低融点インサート材及び第２中間製品と低融点インサート材の少なくとも１組の形状が異形状であることを特徴とする上記２）記載の半溶融鍛造方法
７）高融点金属と高融点インサート材、第１中間製品と低融点インサート材及び第２中間製品と低融点インサート材の少なくとも１組の形状が同径であることを特徴とする上記２）記載の半溶融鍛造方法
８）高融点金属と高融点インサート材、第１中間製品と低融点インサート材及び第２中間製品と低融点インサート材の少なくとも１組の形状が円筒状及び円柱状であり、円筒内径と円柱外径が実質的に同径であることを特徴とする上記２）記載の半溶融鍛造方法
９）高融点金属、インサート材の初期高さｈ_０と高融点金属、インサート材の鍛造後高さｈとの関係が、高融点金属、インサート材を加熱した際の固相率ｆＳのうち一番小さいｆｓ_ｍｉｎとの関係において、
ｌｎ（ｈ_０／ｈ）≧１．５×ｆｓ_ｍｉｎ ^２
を満たすような形状の高融点金属、インサート材を用いることを特徴とする請求項上記１）、３）〜５）の何れか１項に記載の半溶融鍛造方法
１０）中間製品、低融点金属の初期高さｈ_０と中間製品、低融点金属の鍛造後の高さｈとの関係が、中間製品、低融点金属を加熱した際の固相率ｆｓのうち一番小さいｆｓ_ｍｉｎとの関係において、
ｌｎ（ｈ_０／ｈ）≧１．５×ｆｓ_ｍｉｎ ^２
を満たすような形状の中間製品、低融点金属を用いることを特徴とする請求項上記１）、３）〜５）、９）の何れか１項に記載の半溶融鍛造方法
１１）高融点金属、高融点インサート材の初期高さｈ_０と高融点金属、高融点インサート材の鍛造後高さｈとの関係が、高融点金属、高融点インサート材を加熱した際の固相率ｆｓのうち一番小さいｆｓ_ｍｉｎとの関係において、
ｌｎ（ｈ_０／ｈ）≧１．５×ｆｓ_ｍｉｎ ^２
を満たすような形状の高融点金属、高融点インサート材を用いることを特徴とする上記２）、６）〜８）の何れか１項に記載の半溶融鍛造方法
１２）第１中間製品、低融点インサート材の初期高さｈ_０と第１中間製品、低融点インサート材の鍛造後高さｈとの関係が、第１中間製品、低融点インサート材を加熱した際の固相率ｆｓのうち一番小さいｆｓ_ｍｉｎとの関係において、
ｌｎ（ｈ_０／ｈ）≧１．５×ｆｓ_ｍｉｎ ^２
を満たすような形状の第１中間製品、低インサート材を用いることを特徴とする上記２）、６）〜８）、１１）の何れか１項に記載の半溶融鍛造方法
１３）第２中間製品、低融点金属の初期高さｈ_０と第２中間製品、低融点金属の鍛造後高さｈとの関係が、第２中間製品、低融点金属を加熱した際の固相率ｆｓのうち一番小さいｆｓ_ｍｉｎとの関係において、
ｌｎ（ｈ_０／ｈ）≧１．５×ｆｓ_ｍｉｎ ^２
を満たすような形状の２中間製品、低融点金属を用いることを特徴とする上記２）、６）〜８）、１１）、１２）の何れか１項に記載の半溶融鍛造方法
１４）平均５００ｍｍ／ｓ以上の加工速度で成形することを特徴とする上記１）乃至１３）の何れか１項に記載の半溶融鍛造方法
１５）予め２００℃以上に加熱された鍛造型を用いて、平均２００ｍｍ／ｓ以上の加工速度で成形することを特徴とする上記１）乃至１４）の何れか１項に記載の半溶融鍛造方法１６）成形終了後固相線温度以下となるまで最大鍛造荷重の５０％以上の荷重を保持することを特徴とする上記１）乃至１５）の何れか１項に記載の半溶融鍛造方法
にある。
【０００５】
【発明の実施の形態】
鍛造品の部位の必要特性に応じて異なる成分を有する金属素材を用いるが、図１のグラフに示すように、高融点金属素材Ａと低融点金属素材Ｂの固相率ｆ_sが０．３以上０．９未満となる温度域Ｔ_0.3-0.9 が重複しない場合、それぞれの金属素材に対して固相率ｆ_sが０．３以上０．９未満となる温度域Ｔ_0.3-0.9 が重複するような金属をインサート材として用いる。これは、後述するように、金属素材同士を健全に一体化するにはそれぞれの固相率ｆ_sが０．３以上０．９未満となる温度域Ｔ_0.3-0.9 に加熱した後、鍛造することが望ましいからである。異種金属は成分の異なる鋼同士でもよく、その他、鋳鉄、アルミニウム、マグネシウム、チタン等を使用することができる。インサート材は１種類あるいは２種類以上でも良い。
【０００６】
次に加熱温度範囲を異種金属とインサート材の組合せにおいて、それぞれの固相率ｆ_ｓが０．３以上０．９未満となる温度域Ｔ_{０．３−０．９}の重複する範囲に限定する理由を述べる。図２のグラフに示すように、異種金属素材あるいはインサート材の組合せのうち、融点の低い材料Ｅの固相率が０．３になる温度Ｔ_Ｅ _０．３より加熱温度が高い場合、材料Ｅが加熱炉内で自立出来ず、鍛造型内に搬送できない。また異種金属素材あるいはインサート材の組合せのうち、融点の高い材料Ｄの固相率が０．９になる温度Ｔ_Ｄ _０．９より加熱温度が低い場合、材料Ｄの液相成分が少なく、金属素材が鍛造により健全に一体化しない。そのため異種金属素材あるいはインサート材の組合せのうち、それぞれの固相率ｆ_ｓが０．３以上０．９未満となる温度域Ｔ_{０．３−０．９}の重複する範囲の温度に加熱する。
【０００７】
異種金属とインサート材の組合せにおいて、それぞれの固相率ｆ_sが０．３以上０．９未満となる温度域Ｔ_0.3-0.9 の重複する範囲の温度が高い順に、順次加熱、鍛造を行う。これは２回目以降の加熱において、既に鍛造された異種金属あるいはインサート材の組合せのうち、固相率ｆ_sが０．３以上０．９未満となる温度域Ｔ_0.3-0.9 の低い材料が加熱炉内で溶け落ちるのを防止するためである。
【０００８】
異種金属、インサート材あるいは中間製品の形状は、例えば図３ないし図５（いずれも（ａ）は平面図、（ｂ）は側面図）に示すように、一回目の鍛造を行った後、異形状であっても、同径形状であっても、円筒及び円柱であり円筒内径と円柱径が実質的に同径である場合でもよい。
【０００９】
前記高融点金属とインサート材を鍛造して中間製品を得る工程、必要に応じて中間製品とインサート材を鍛造してさらに中間製品を得る工程、中間製品と低融点金属を鍛造して最終製品を得る工程において、高融点金属、インサート材、低融点金属のそれぞれの初期高さｈ_０と高融点金属、インサート材、低融点金属のそれぞれ鍛造後高さｈとの関係が、高融点金属、インサート材、低融点金属のそれぞれの組み合わせで加熱した際の固相率ｆ_ｓのうち一番小さいｆ_ｓｍｉｎとの関係において、
ｌｎ（ｈ_０／ｈ）≧１．５×ｆ_ｓｍｉｎ ^２
を満たすような形状の高融点金属、インサート材、低融点金属を用いる各金属素材を用いるのは、各金属素材が十分な加工を受け、液相同士を十分に混合し一体化させるためである。
【００１０】
鍛造時に平均５００ｍｍ／秒以上の加工速度で成形するのは、これより遅い加工速度では鍛造型との接触により加熱された金属素材の温度が低下し、金属素材同士が十分に一体化しないからである。加工速度の上限は、本発明の効果を得るためには特に制限する必要はなく、設備能力に依存する。
【００１１】
予め２００℃以上に加熱された型を用いる場合には、鍛造型との接触による金属素材の温度低下が緩和されるため、鍛造時の加工速度は平均２００ｍｍ／秒以上で十分である。加熱温度の上限は、本発明の効果を得るためには特に制限する必要はないが、金型の焼き戻し軟化を防止するため、５００℃以下とすることが好ましい。
【００１２】
成形終了後固相線温度以下となるまで最大鍛造荷重の少なくとも５０％以上の荷重を保持させるのは、凝固収縮による鋳巣の発生を防止し、鍛造後の材質特性を向上させるためである。最大鍛造荷重の５０％未満の荷重ではその効果は十分ではない。保持荷重の上限は、本発明の効果を得るためには特に制限する必要はなく、最大鍛造荷重の１００％でも構わない。
【００１３】
【実施例】
（実施例１）
実施例として、２種類の金属４Ａ、４Ｂ及びインサート材４Ｃで構成される図６（（ａ）は平面図、（ｂ）は側面図）に示すような形状の鍛造品の鍛造を実施した。
素材には表１の化学成分を有する高融点材料である素材Ａ、低融点材料である素材Ｂ及びインサート材料である素材Ｃを用いた。また示差熱分析により測定した固相線温度と液相線温度をそれぞれ表２に示した。
【００１４】
【表１】

【００１５】
【表２】

【００１６】
鍛造素材として、図７に示すように、外径Ｄ_A0、内径ｄ_A0、高さｈ_A0の円筒形状である素材５Ａと、外径Ｄ_B0、高さｈ_B0の円柱形状である素材５Ｂ、外径Ｄ_C0、内径ｄ_C0、高さｈ_C0の円筒形状である素材５Ｃを準備した。
【００１７】
１回目の鍛造で素材５Ａと素材５Ｃの鍛造を行い図８に示すように素材５Ａと素材５Ｃからなる中間製品５Ｄを成形した後、２回目の鍛造で中間製品５Ｄと素材５Ｂの鍛造を行い図６に示す鍛造品１を成形した。表３に１回目の鍛造条件を、表４に２回目の鍛造条件を示す。加熱時における金属素材の固相率は、金属素材を加熱後速やかに水冷することにより組織を凍結、光学顕微鏡にて観察し、固相部分の面積率を測定することにより求めた。
【００１８】
【表３】

【００１９】
【表４】

【００２０】
鍛造品の品質を評価するため、内部空孔有無の観察及び引張試験を実施した。内部空孔に関しては、鍛造品１の断面を切断，研磨し、光学顕微鏡にて空孔の有無を観察した。鍛造品１の図６に示す位置からφ６のサンプル４２を切り出し、ねじ部を圧接することにより引張試験片を作製した。引張試験は常温で行った。表５に評価結果を示す。
【００２１】
【表５】

【００２２】
試験Ｎｏ．１〜４では、いずれの場合も鍛造品に内部空孔は見られず完全に一体化しており、引張強さが４００ＭＰａ以上を示した。また破断位置は強度の低い金属Ｂの位置であった。
【００２３】
１回目の鍛造での対数ひずみが小さい試験Ｎｏ．５、６では、素材Ａと素材Ｃの一体化がやや不十分で、素材Ａと素材Ｃの境界にわずかな空孔が見られ、引張試験では素材Ａと素材Ｂの境界から破断した。
２回目の鍛造での対数ひずみが小さい試験Ｎｏ．７、８では、素材Ｂと素材Ｃの一体化がやや不十分で、素材Ｂと素材Ｃの境界にわずかな空孔が見られ、引張試験では素材Ｂと素材Ｃの境界から破断した。
【００２４】
１回目の鍛造での加工速度が小さい試験Ｎｏ．９、１０では、加工中に鍛造型との接触により温度低下が生じ、液相部分が減少したため、素材Ａと素材Ｃの一体化がやや不十分であり、素材Ａと素材Ｃの境界にわずかに空孔が見られ、引張試験では素材Ａと素材Ｃの境界から破断した。
【００２５】
１回目の鍛造後の荷重保持が小さい試験Ｎｏ．１１では、素材Ａと素材Ｃの境界に凝固収縮に伴う微細な鋳巣と思われる空孔が見られ、引張試験では素材Ａと素材Ｃの境界から破断した。
【００２６】
２回目の鍛造での加工速度が小さい試験Ｎｏ．１２、１３では、加工中に鍛造型との接触により温度低下が生じ、液相部分が減少したため、素材Ｂと素材Ｃの一体化がやや不十分であり、素材Ｂと素材Ｃの境界にわずかに空孔が見られ、引張試験では素材Ｂと素材Ｃの境界から破断した。
【００２７】
２回目の鍛造後の荷重保持が小さい試験Ｎｏ．１４では、素材Ｂと素材Ｃの境界に凝固収縮に伴う微細な鋳巣と思われる空孔が見られ、引張試験では素材Ｂと素材Ｃの境界から破断した。。
【００２８】
１回目の鍛造で、素材Ａの固相率が１．０となる温度に加熱した試験Ｎｏ．１５では、素材Ａと素材Ｃの一体化が不十分であり、素材Ａと素材Ｃの境界に空孔が見られ、引張試験では素材Ａと素材Ｃの境界から破断した。
【００２９】
２回目の鍛造で、素材Ａと素材Ｃからなる中間製品のうち素材Ｃの固相率が１．０となる温度に加熱した試験Ｎｏ．１７では、素材Ｂと素材Ｃの一体化が不十分であり、素材Ｂと素材Ｃの境界に空孔が見られ、引張試験では素材Ｂと素材Ｃの境界から破断した。
【００３０】
１回目の鍛造で、素材Ｂの固相率が０．１となる温度に加熱した試験Ｎｏ．１６では、加熱炉内で金属素材Ｂが部分的に熔け落ち、鍛造型への搬送が出来なかった。
２回目の鍛造で、素材Ａと素材Ｃからなる中間製品のうち素材Ｃの固相率の固相率が０．１となる温度に加熱した試験Ｎｏ．１８では、加熱炉内で金属素材Ｃが部分的に熔け落ち、鍛造型への搬送が出来なかった。
したがって、試験Ｎｏ．１６、１８は鍛造品の引張試験を実施できなかった。
【００３１】
（実施例２）
本発明外の実施例として、実施例１と同様に２種類の金属及びインサート材で構成される図６に示すような形状である鍛造品の鍛造を実施した。素材は実施例１で用いた表１と同じである。
鍛造素材として、図９に示すように、外径Ｄ_A0、内径ｄ_A0、高さｈ_A0の円筒形状である素材６Ａと、外径Ｄ_B0、高さｈ_B0の円柱形状である素材６Ｂ、外径Ｄ_C0、内径ｄ_C0、高さｈ_C0の円筒形状である素材６Ｃを準備した。
【００３２】
１回目の鍛造で素材６Ｂと素材６Ｃの鍛造を行い図１０に示すように素材６Ｂと素材６Ｃからなる中間製品６Ｄを成形した後、２回目の鍛造で中間製品６Ｄと素材６Ａの鍛造を行い第４図に示す鍛造品１を成形した。表６に１回目の鍛造条件を、表７に２回目の鍛造条件を示す。
鍛造品の品質を評価するため、実施例１と同様に、内部空孔有無の観察及び引張試験を実施した。表８に評価結果を示す。
【００３３】
【表６】

【００３４】
【表７】

【００３５】
【表８】

【００３６】
２回目の鍛造で、素材Ｂと素材Ｃからなる中間製品Ｄのうち素材Ｂの固相率が０．０となる温度に中間製品Ｄを加熱した試験Ｎｏ．１９では、加熱炉内で金属素材Ｂが熔け落ち、鍛造型への搬送が出来なかった。したがって、試験Ｎｏ．１９は鍛造品の引張試験を実施できなかった。
【００３７】
２回目の鍛造で、素材Ａの固相率が１．０となる温度に加熱した試験Ｎｏ．２０では、素材Ａと素材Ｃの一体化が不十分であり、素材Ａと素材Ｃの境界に空孔が見られ、引張試験では素材Ａと素材Ｃの境界から破断した。
【００３８】
実施例２では、２回目の鍛造で、素材Ｂと素材Ｃからなる中間製品Ｄのうち素材Ｂの固相率が０．３以上０．９未満となる温度域Ｔ_0.3-0.9 と素材Ａの固相率が０．３以上０．９未満となる温度域Ｔ_0.3-0.9 が無いため、健全な鍛造品を得ることは出来なかった。
【００３９】
（実施例３）
本発明外の実施例として、図１１（（ａ）は平面図、（ｂ）は側面図）に示すような形状をもつ２種類の金属で構成される鍛造品の鍛造を実施した。素材は実施例１で用いた表１の内、素材Ａと素材Ｂである。表９に鍛造条件を示す。
【００４０】
【表９】

【００４１】
鍛造素材として、図１２に示すように、外径Ｄ_A0、内径ｄ_A0、高さｈ_A0の円筒形状である素材８Ａと、外径Ｄ_B0、高さｈ_B0の円柱形状である素材８Ｂを準備した。
鍛造品の品質を評価するため、実施例１と同様に、内部空孔有無の観察及び引張試験を実施した。表１０に評価結果を示す。
【００４２】
【表１０】

【００４３】
素材Ｂの固相率が０．０となる温度に素材Ｂを加熱した試験Ｎｏ．２１では、加熱炉内で金属素材Ｂが熔け落ち、鍛造型への搬送が出来なかった。したがって、試験Ｎｏ．２１は鍛造品の引張試験を実施できなかった。
素材Ａの固相率が１．０となる温度に加熱した試験Ｎｏ．２２では、素材Ａと素材Ｂの一体化が不十分であり、素材Ａと素材Ｂの境界に空孔が見られ、引張試験では素材Ａと素材Ｂの境界から破断した。
【００４４】
実施例３では、インサート材を用いておらず、素材Ａの固相率が０．３以上０．９未満となる温度域Ｔ_0.3-0.9 と素材Ｂの固相率が０．３以上０．９未満となる温度域Ｔ_0.3-0.9 が無いため、健全な鍛造品を得ることは出来なかった。
【００４５】
【発明の効果】
本発明では、融点の大きく異なる異種金属からなる鍛造品を成形する際、インサート材を加えて順次固液共存温度域に加熱して、鍛造，一体化させることにより、高歩留まりかつ少数回の鍛造工程で部位に応じた金属素材を用いた複雑形状部品を鍛造でき、自動車，機械用部品等を低コストで提供できる。
【図面の簡単な説明】
【図１】利用可能な素材の組合せと加熱温度範囲
【図２】加熱温度範囲
【図３】金属素材の組合せ方の例
【図４】金属素材の組合せ方の例
【図５】金属素材の組合せ方の例
【図６】鍛造品
【図７】鍛造に用いる金属素材
【図８】第１回目鍛造後の中間製品
【図９】鍛造に用いる金属素材
【図１０】第１回目鍛造後の中間製品
【図１１】鍛造品
【図１２】鍛造に用いる金属素材
【符号の説明】
１Ａ高融点金属素材
１Ｂ角柱である低融点金属素材
１Ｃインサート材
１Ｄ円柱である中間製品
２Ａ高融点金属素材
２Ｂ同径の円柱である低融点金属素材
２Ｃインサート材
２Ｄ同径の円柱である中間製品
３Ａ高融点金属素材
３Ｂ同径の内径を持つ円筒である低融点金属素材
３Ｃインサート材
３Ｄ同径の円柱である中間製品
４１鍛造品
４２引張試験片採取位置
４Ａ金属素材Ａからなる部位
４Ｂ金属素材Ｂからなる部位
４Ｃ金属素材Ｃからなる部位
５Ａ鍛造に用いる金属素材Ａ
５Ｂ鍛造に用いる金属素材Ｂ
５Ｃ鍛造に用いる金属素材Ｂ
５Ｄ金属素材Ａと金属素材Ｃからなる中間製品
６Ａ鍛造に用いる金属素材Ａ
６Ｂ鍛造に用いる金属素材Ｂ
６Ｃ鍛造に用いる金属素材Ｂ
６Ｄ金属素材Ｂと金属素材Ｃからなる中間製品
７１鍛造品
７２引張試験片採取位置
７Ａ金属素材Ａからなる部位
７Ｂ金属素材Ｂからなる部位[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a part made of a dissimilar metal, and particularly to a method for manufacturing a part having a complicated shape.
[0002]
[Prior art]
Up to now, as a method for joining and integrating dissimilar metals, a joining method in a solid phase temperature range, a liquid phase temperature range or a solid-liquid coexisting temperature range has been disclosed. For example, in the solid phase temperature range, Japanese Patent Application Laid-Open No. 56-128688 discloses a method of increasing the joining surface strength by forming hot irregularities on the metal surfaces to be joined and then performing hot isostatic pressing. In the liquid phase temperature range, Japanese Patent Application Laid-Open No. 63-295077 discloses a method in which one surface of a metal to be joined is melted and then the other metal is pressed and cooled. Furthermore, in the solid-liquid coexistence temperature region, one of the metals to be joined is heated to the solid-liquid coexistence temperature region in the literature (Volume of Plastic Processing Joint Lecture Vol. 48th PAGE. 407-408 1997). A method of cooling after insertion is disclosed.
[0003]
[Problems to be Solved by the Invention]
However, in Japanese Patent Application Laid-Open Nos. 56-128688 and 63-295077, when manufacturing complex-shaped parts by joining and integrating dissimilar metals, the respective metal bodies are preliminarily formed into shapes constituting the final shape. It is necessary to finish, and then a method of joining dissimilar metals must be adopted, leading to an increase in manufacturing cost. In addition, in the literature, it is possible to manufacture parts with specific shapes such as finned parts at a low cost, but they do not actively create part shapes and are difficult to apply to parts with other shapes. Also, the bonding strength is insufficient.
The present invention has been made in view of the above points, and by using two or more kinds of different metal materials having an extremely simple shape, complex shaped parts made of different metals are formed with a high yield and a small number of forging processes. And it aims at improving the intensity | strength of a joint surface.
[0004]
[Means for Solving the Problems]
That is, the gist of the present invention is that
1) In a method for manufacturing a forged part made of a high melting point metal and a low melting point metal that do not overlap each _{other in} a temperature range T _{0.3-0.9 in which} the solid phase ratio fS is 0.3 or more and less than 0.9, On the other hand, an overlapping single metal having a temperature range T _0.3-0.9 in which the solid phase ratio fS is 0.3 or more and less than 0.9 is used as the insert material, and the refractory metal and the insert material are each _fixed. After the intermediate product is manufactured by heating, inserting into a forging die and forging to an overlapping temperature in the temperature range T _0.3-0.9 where the phase ratio fS is 0.3 or more and less than 0.9, the intermediate product And the low melting point metal is heated to an overlapping temperature T _0.3-0.9 at which the solid phase ratio fS of the insert material and the low melting point metal is 0.3 or more and less than 0.9, and is inserted into the forging die. Semi-molten forging method characterized by forging and integrating 2) Solid phase ratio fS of 0.3 or more and 0.9 or less In the method for manufacturing a forged component made of a refractory metal and a low melting metal not overlapping temperature region T _0.3-0.9 serving as the solid phase rate fS is less than 0.3 to 0.9 for each metal A plurality of insert materials having different melting points with overlapping temperature ranges T _0.3-0.9 are used, and each of the high melting point metal material and the high melting point insert material has a solid phase ratio fS of 0.3 or more and 0.9. The first intermediate product is manufactured by heating to an overlapping temperature in the temperature range T _0.3-0.9 , being inserted into the forging die, and forging, and the first intermediate product and the low melting point insert are _{Heating to} the overlapping temperature range T _0.3-0.9 where the solid phase ratio fS of the melting point insert material and the low melting point insert material is 0.3 or more and less than 0.9, insert into the forging die, forging (2) After manufacturing the intermediate product, the second intermediate product and the low melting point metal are mixed with the low melting point insert material and the low melting point metal. _{Heating to} an overlapping temperature in the temperature range T _0.3-0.9 where the solid phase ratio fS of the melting point metal is 0.3 or more and less than 0.9, inserting into a forging die, forging and integrating. The semi-molten forging method 3) The semi-molten forging method 4) according to the above 1), wherein at least one of the shapes of the high melting point metal, the insert material, the intermediate product, and the low melting point metal is different. The semi-molten forging method according to 1) above, wherein at least one pair of shapes of the metal, the insert material, the intermediate product, and the low melting point metal has the same diameter 5) The high melting point metal, the insert material, the intermediate material, and the low melting point The semi-molten forging method 6) according to 1) above, wherein at least one pair of shapes of the metal is cylindrical and columnar, and the inner diameter of the cylinder and the outer diameter of the column are substantially the same. High melting point insert, first intermediate product and low melting point insert The semi-molten forging method according to 2) above, wherein the shape of at least one of the first and second intermediate products and the low-melting-point insert material is different, 7) the high-melting-point metal and the high-melting-point insert material, the first The semi-molten forging method according to 2) above, wherein at least one pair of the intermediate product and the low melting point insert material and the second intermediate product and the low melting point insert material have the same diameter. At least one set of the insert material, the first intermediate product and the low-melting-point insert material, and the second intermediate product and the low-melting-point insert material has a cylindrical shape and a cylindrical shape, and the cylindrical inner diameter and the cylindrical outer diameter are substantially the same diameter. thixoforging method 9) a refractory metal above 2), wherein that, the refractory metal and the initial height h ₀ of the insert material, the relationship between the height h after forging the insert material, a refractory metal Heat the insert material In relation to the smallest _{fs min} of solid fraction fS of time,
ln (h ₀ /h)≧1.5×fs _min ²
A semi-molten forging method according to any one of claims 1), 3) to 5), characterized in that a refractory metal and an insert material having a shape satisfying the above requirements are used. initial height h ₀ and the intermediate products, the relationship between the height h after forging the low melting point metal, an intermediate product, the relationship between the smallest fs _min of the solid phase rate fs upon heating the low melting point metal In
ln (h ₀ /h)≧1.5×fs _min ²
The intermediate product having a shape satisfying the above requirements, a low melting point metal is used, The semi-molten forging method according to any one of the above 1), 3) to 5), 9) 11) a high melting point metal The relationship between the initial height h ₀ of the high melting point insert material and the height h after forging of the high melting point metal and high melting point insert material is the solid phase ratio fs when the high melting point metal and high melting point insert material are heated. In relation to the smallest fs _min ,
ln (h ₀ /h)≧1.5×fs _min ²
The semi-molten forging method 12) according to any one of 2) and 6) to 8) above, wherein a refractory metal and a refractory insert material having a shape satisfying the above requirements are used. the initial height h ₀ of the melting insert material first intermediate product, the relationship between the height h after forging of low melting insert material, the first intermediate product, of the solid phase rate fs upon heating the low-melting insert material In relation to the smallest fs _min ,
ln (h ₀ /h)≧1.5×fs _min ²
A semi-molten forging method according to any one of 2), 6) to 8), 11) above, characterized in that a first intermediate product and a low insert material having a shape satisfying the above requirements are used. product, the initial height h ₀ of the low-melting-point metal second intermediate product, the relationship between the height h after forging the metal having a low melting point, the second intermediate product, of the solid phase rate fs upon heating the low melting point metal In relation to the smallest fs _min ,
ln (h ₀ /h)≧1.5×fs _min ²
The semi-molten forging method according to any one of 2), 6) to 8), 11), and 12) above, characterized in that a 2 intermediate product and a low melting point metal having a shape satisfying the requirements are used. The semi-molten forging method 15 according to any one of 1) to 13) above, wherein molding is performed at a processing speed of 500 mm / s or more, and average using a forging die heated to 200 ° C. or higher in advance. The semi-molten forging method 16 according to any one of 1) to 14) above, wherein the molding is performed at a processing speed of 200 mm / s or more. The semi-molten forging method according to any one of 1) to 15) above, wherein a load of 50% or more is maintained.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
A metal material having different components is used depending on the required characteristics of the forged part. As shown in the graph of FIG. 1, the solid phase ratio f _s of the high melting point metal material A and the low melting point metal material B is 0.3. If the temperature range T _0.3-0.9 comprising less than 0.9 or more non-overlapping temperature region T _0.3-0.9 to solid phase ratio f _s for each metal material is less than 0.3 or more 0.9 duplicate Such a metal is used as an insert material. As will be described later, in order to integrate the metal materials in a sound manner, each solid fraction fs is heated to a temperature range T _0.3-0.9 where the solid phase ratio f _s is 0.3 or more and less than 0.9, and then forged. This is because it is desirable. Different metals may be steels having different components, and cast iron, aluminum, magnesium, titanium, and the like can be used. One type or two or more types of insert materials may be used.
[0006]
Next, the heating temperature range is limited to the overlapping range of the temperature range T _0.3-0.9 in which the solid phase ratio f _s is 0.3 or more and less than 0.9 in the combination of the dissimilar metal and the insert material. Give the reason. As shown in the graph of FIG. 2, when the heating temperature is higher than the temperature T _E _0.3 at which the solid phase ratio of the material E having a low melting point is 0.3 in the combination of different metal materials or insert materials, the material E However, it cannot stand by itself in the heating furnace and cannot be transferred into the forging die. Further, in the combination of different metal materials or insert materials, when the heating temperature is lower than the temperature T _D _0.9 at which the solid phase ratio of the material D having a high melting point becomes 0.9, the liquid phase component of the material D is small and the metal The material is not soundly integrated by forging. Therefore among the combinations of dissimilar metallic material or insert material, each of the solid phase ratio _{f s} is heated to overlapping range of the temperature of the temperature range _{T 0.3-0.9} comprising less than 0.3 to 0.9.
[0007]
In the combination of the different metal and the insert material, heating and forging are sequentially performed in descending order of the temperature in the overlapping range of the temperature range T _0.3-0.9 where the solid phase ratio f _s is 0.3 or more and less than 0.9. Which in the heating of the second and subsequent, among the combinations of the previously forged different metals or insert material, a low temperature region T _0.3-0.9 to solid phase ratio f _s is less than 0.3 or more 0.9 material heating This is to prevent melting in the furnace.
[0008]
For example, as shown in FIGS. 3 to 5 (both (a) is a plan view and (b) is a side view), the shape of the dissimilar metal, insert material or intermediate product is different after the first forging. It may be a shape, the same diameter shape, or a cylinder and a column, and the cylinder inner diameter and the column diameter may be substantially the same.
[0009]
Forging the refractory metal and insert material to obtain an intermediate product, forging the intermediate product and insert material as necessary to obtain an intermediate product, forging the intermediate product and low melting point metal to produce a final product In the obtaining step, the relationship between the initial height h ₀ of each of the high melting point metal, the insert material and the low melting point metal and the height h after forging of each of the high melting point metal, the insert material and the low melting point metal is In relation to the smallest f _smin among the solid phase ratios f _s when heated by a combination of a material and a low melting point metal,
ln (h ₀ /h)≧1.5×f _smin ²
The reason why each metal material using a high melting point metal, an insert material, and a low melting point metal satisfying the above conditions is used is that each metal material is sufficiently processed and the liquid phases are sufficiently mixed and integrated. .
[0010]
The reason for forming at a processing speed of 500 mm / sec or more on average during forging is that at a lower processing speed, the temperature of the metal material heated by the contact with the forging die is lowered and the metal materials are not sufficiently integrated with each other. is there. The upper limit of the processing speed is not particularly limited in order to obtain the effect of the present invention, and depends on the equipment capacity.
[0011]
When using a die that has been heated to 200 ° C. or higher in advance, since the temperature drop of the metal material due to contact with the forging die is alleviated, an average processing speed of 200 mm / second or more during forging is sufficient. The upper limit of the heating temperature is not particularly limited in order to obtain the effects of the present invention, but is preferably 500 ° C. or lower in order to prevent temper softening of the mold.
[0012]
The reason why the load of at least 50% of the maximum forging load is maintained until the temperature becomes below the solidus temperature after the completion of molding is to prevent the formation of a cast hole due to solidification shrinkage and improve the material properties after forging. The effect is not sufficient when the load is less than 50% of the maximum forging load. The upper limit of the holding load is not particularly limited in order to obtain the effect of the present invention, and may be 100% of the maximum forging load.
[0013]
【Example】
(Example 1)
As an example, forging of a forged product having a shape shown in FIG. 6 ((a) is a plan view and (b) is a side view) composed of two types of

metals

4A and 4B and an insert material 4C was performed.
The material used was material A, which is a high melting point material having the chemical components shown in Table 1, material B, which is a low melting point material, and material C, which is an insert material. The solidus temperature and liquidus temperature measured by differential thermal analysis are shown in Table 2, respectively.
[0014]
[Table 1]

[0015]
[Table 2]

[0016]
As the forging material, as shown in FIG. 7, a material 5A having a cylindrical shape with an outer diameter D _A0 , an inner diameter d _A0 and a height h _A0 , and a material 5B having a cylindrical shape with an outer diameter D _B0 and a height h _B0 , A cylindrical material 5C having an outer diameter D _C0 , an inner diameter d _C0 , and a height h _C0 was prepared.
[0017]
The forging of the material 5A and the material 5C is performed by the first forging and the intermediate product 5D made of the material 5A and the material 5C is formed as shown in FIG. 8, and then the intermediate product 5D and the material 5B are forged by the second forging. A forged product 1 shown in FIG. 6 was formed. Table 3 shows the first forging conditions, and Table 4 shows the second forging conditions. The solid fraction of the metal material at the time of heating was determined by freezing the metal material immediately after heating and freezing the tissue, observing it with an optical microscope, and measuring the area fraction of the solid phase portion.
[0018]
[Table 3]

[0019]
[Table 4]

[0020]
In order to evaluate the quality of the forged product, the presence or absence of internal voids and a tensile test were performed. Regarding the internal voids, the cross section of the forged product 1 was cut and polished, and the presence or absence of voids was observed with an optical microscope. A sample of φ6 was cut out from the position shown in FIG. 6 of the forged product 1, and a tensile test piece was prepared by press-contacting the threaded portion. The tensile test was performed at room temperature. Table 5 shows the evaluation results.
[0021]
[Table 5]

[0022]
Test No. In all cases, the inner holes were not found in the forged product, and the tensile strength was 400 MPa or more. The breaking position was the position of metal B having low strength.
[0023]
Test No. with low logarithmic strain in the first forging In Examples 5 and 6, the integration of the material A and the material C was slightly insufficient, and a slight hole was observed at the boundary between the material A and the material C. In the tensile test, fracture occurred from the boundary between the material A and the material B.
Test No. with low logarithmic strain in the second forging 7 and 8, the integration of the material B and the material C was slightly insufficient, and a slight hole was observed at the boundary between the material B and the material C. In the tensile test, fracture occurred from the boundary between the material B and the material C.
[0024]
Test No. with low processing speed in the first forging. In Nos. 9 and 10, the temperature decreased due to contact with the forging die during processing, and the liquid phase portion was reduced. Therefore, the integration of the material A and the material C was slightly insufficient, and the boundary between the material A and the material C was slightly small. In the tensile test, fracture occurred from the boundary between the material A and the material C.
[0025]
Test No. with small load retention after the first forging. In No. 11, voids that appear to be fine voids due to solidification shrinkage were found at the boundary between the material A and the material C, and fractured from the boundary between the material A and the material C in the tensile test.
[0026]
Test No. 2 with low processing speed in the second forging. In Nos. 12 and 13, the temperature decreased due to contact with the forging die during processing, and the liquid phase portion was reduced. Therefore, the integration of the material B and the material C was slightly insufficient, and there was a slight gap between the material B and the material C. In the tensile test, fracture occurred from the boundary between the material B and the material C.
[0027]
Test No. with small load retention after the second forging. In No. 14, voids that appear to be fine voids due to solidification shrinkage were found at the boundary between the material B and the material C, and fractured from the boundary between the material B and the material C in the tensile test. .
[0028]
Test No. 1 was heated to a temperature at which the solid phase ratio of material A was 1.0 in the first forging. 15, the integration of the material A and the material C was insufficient, and voids were seen at the boundary between the material A and the material C, and fractured from the boundary between the material A and the material C in the tensile test.
[0029]
Test No. 2 was heated to a temperature at which the solid phase ratio of material C among the intermediate products made of material A and material C was 1.0 in the second forging. In No. 17, the integration of the material B and the material C was insufficient, and voids were observed at the boundary between the material B and the material C, and fractured from the boundary between the material B and the material C in the tensile test.
[0030]
Test No. 1 was heated to a temperature at which the solid fraction of material B was 0.1 in the first forging. In No. 16, the metal material B partially melted in the heating furnace, and could not be transferred to the forging die.
In the second forging, among the intermediate products made of material A and material C, test No. 1 was heated to a temperature at which the solid phase ratio of material C was 0.1. In No. 18, the metal material C partially melted in the heating furnace and could not be conveyed to the forging die.
Therefore, test no. 16 and 18 could not carry out the tensile test of the forged product.
[0031]
(Example 2)
As an example outside the present invention, forging of a forged product having a shape as shown in FIG. 6 composed of two kinds of metals and an insert material was carried out in the same manner as in Example 1. The material is the same as in Table 1 used in Example 1.
As the forging material, as shown in FIG. 9, a material 6A having a cylindrical shape with an outer diameter D _A0 , an inner diameter d _A0 and a height h _A0 , and a material 6B having a cylindrical shape with an outer diameter D _B0 and a height h _B0 , A cylindrical material 6C having an outer diameter D _C0 , an inner diameter d _C0 , and a height h _C0 was prepared.
[0032]
The forging of the material 6B and the material 6C is performed by the first forging and the intermediate product 6D made of the material 6B and the material 6C is formed as shown in FIG. 10, and then the forging of the intermediate product 6D and the material 6A is performed by the second forging. A forged product 1 shown in FIG. 4 was formed. Table 6 shows the first forging conditions, and Table 7 shows the second forging conditions.
In order to evaluate the quality of the forged product, as in Example 1, the presence or absence of internal vacancies and a tensile test were performed. Table 8 shows the evaluation results.
[0033]
[Table 6]

[0034]
[Table 7]

[0035]
[Table 8]

[0036]
Test No. 2 in which the intermediate product D was heated to a temperature at which the solid phase ratio of the material B among the intermediate products D made of the materials B and C was 0.0 in the second forging. In No. 19, the metal material B melted in the heating furnace and could not be transferred to the forging die. Therefore, test no. No. 19 could not carry out the tensile test of the forged product.
[0037]
Test No. 2 was heated to a temperature at which the solid phase ratio of material A was 1.0 in the second forging. In No. 20, the integration of the material A and the material C was insufficient, and voids were observed at the boundary between the material A and the material C, and fractured from the boundary between the material A and the material C in the tensile test.
[0038]
In Example 2, in the second forging, the temperature range T _{0.3-0.9 in} which the solid phase ratio of the material B of the intermediate product D made of the material B and the material C is 0.3 or more and less than 0.9 and the material A Since there was no temperature range T _0.3-0.9 where the solid phase ratio was 0.3 or more and less than 0.9, a sound forged product could not be obtained.
[0039]
(Example 3)
As an example outside the present invention, forging of a forged product having two shapes as shown in FIG. 11 ((a) is a plan view and (b) is a side view) was performed. The materials are Material A and Material B in Table 1 used in Example 1. Table 9 shows the forging conditions.
[0040]
[Table 9]

[0041]
As the forging material, as shown in FIG. 12, a material 8A having a cylindrical shape with an outer diameter D _A0 , an inner diameter d _A0 and a height h _A0 , and a material 8B having a cylindrical shape with an outer diameter D _B0 and a height h _B0 are used. Got ready.
In order to evaluate the quality of the forged product, as in Example 1, the presence or absence of internal vacancies and a tensile test were performed. Table 10 shows the evaluation results.
[0042]
[Table 10]

[0043]
Test No. 1 in which material B was heated to a temperature at which the solid phase ratio of material B was 0.0. In No. 21, the metal material B melted down in the heating furnace and could not be transferred to the forging die. Therefore, test no. No. 21 could not carry out the tensile test of the forged product.
Test No. 1 was heated to a temperature at which the solid phase ratio of material A was 1.0. In No. 22, the integration of the material A and the material B was insufficient, and voids were observed at the boundary between the material A and the material B. In the tensile test, fracture occurred from the boundary between the material A and the material B.
[0044]
In Example 3, no insert material was used, the temperature range T _{0.3-0.9 in} which the solid phase ratio of the material A was 0.3 or more and less than 0.9, and the solid phase ratio of the material B was 0.3 or more and _0.00 . Since there was no temperature range T _0.3-0.9 that would be less than 9, a sound forged product could not be obtained.
[0045]
【The invention's effect】
In the present invention, when forming a forged product made of dissimilar metals having greatly different melting points, an insert material is added and sequentially heated to a solid-liquid coexistence temperature range, and forged and integrated, thereby achieving high yield and a small number of forgings. It is possible to forge complex shaped parts using metal materials according to the site in the process, and to provide automobiles, machine parts, etc. at low cost.
[Brief description of the drawings]
[Fig. 1] Combination of available materials and heating temperature range [Fig. 2] Heating temperature range [Fig. 3] Example of how to combine metal materials [Fig. 4] Example of how to combine metal materials [Fig. Example of combination [Fig. 6] Forged product [Fig. 7] Metal material used for forging [Fig. 8] Intermediate product after the first forging [Fig. 9] Metal material used for forging [Fig. 10] After the first forging Intermediate products [Fig. 11] Forged products [Fig. 12] Metal materials used for forging [Explanation of symbols]
1A high melting point metal material 1B low melting point metal material 1C prismatic material 1C insert material 1D intermediate product 2C high melting point metal material 2B low melting point metal material 2C same diameter cylinder insert material 2D intermediate product which is a same diameter cylinder 3A High melting point metal material 3B Low melting point metal material 3C which is a cylinder having the same inner diameter. Insert material 3D Intermediate product 41 which is a cylinder having the same diameter 41 Forging product 42 Tensile specimen collection position 4A Part consisting of metal material A 4B Metal material Part 4C made of B Part 5A made of metal material C Metal material A used for forging
5B Metal material B used for forging
Metal material B used for 5C forging
5D Intermediate product 6A consisting of metal material A and metal material C Metal material A used for forging
6B Metal material B used for forging
6C Metal material B used for forging
6D Intermediate product 71 made of metal material B and metal material C Forged product 72 Tensile specimen collection position 7A Site made of metal material A 7B Site made of metal material B

Claims

In a method for manufacturing a forged part made of a high melting point metal and a low melting point metal that do not overlap each _{other in} a temperature range T _{0.3-0.9 in which} the solid phase ratio f _S is 0.3 or more and less than 0.9, Using a single overlapping metal in the temperature region T _0.3-0.9 where the solid phase ratio f _S is 0.3 or more and less than 0.9 as the insert material, the refractory metal and the insert material are each _fixed. After heating to an overlapping temperature in the temperature range T _0.3-0.9 where the phase ratio f _S is 0.3 or more and less than 0.9 , inserting into a forging die and forging to produce an intermediate product, the intermediate The product and the low melting point metal are heated to the overlapping temperature in the temperature range T _0.3-0.9 where the solid phase ratio f _S between the insert material and the low melting point metal is 0.3 or more and less than 0.9 . A semi-molten forging method characterized in that it is inserted into, forged, and integrated.

In a method for manufacturing a forged part made of a high melting point metal and a low melting point metal that do not overlap each _{other in} a temperature range T _{0.3-0.9 in which} the solid phase ratio f _S is 0.3 or more and less than 0.9, Using a plurality of insert materials having different melting points and having a temperature range T _{0.3-0.9 in} which the solid phase ratio f _S is 0.3 or more and less than 0.9, and using a high melting point metal material and a high melting point insert material , _Heated to overlapping temperatures in the temperature range T _0.3-0.9 where the solid phase ratio f _S is 0.3 or more and less than 0.9, inserted into the forging die, forged, and the first intermediate product The first intermediate product and the low-melting-point insert material are manufactured in a temperature region T _{0.3-0. Where} the solid phase ratio f _S of the high-melting-point insert material and the low-melting-point insert material is 0.3 or more and less than 0.9 _{. 9} overlapping heated to a temperature, inserted into the forging die, after manufacturing the forged second intermediate product, low and said second intermediate product Point metal, heated to a redundant temperature of the temperature range _{T 0.3-0.9} to solid fraction _{f S} of the low melting point metal and a low melting insert material is less than 0.3 to 0.9, in the forging die A semi-molten forging method characterized in that it is integrated by insertion and forging.

The semi-molten forging method according to claim 1, wherein at least one pair of shapes of the high melting point metal, the insert material, the intermediate product, and the low melting point metal is different.

The semi-molten forging method according to claim 1, wherein at least one pair of shapes of the high melting point metal, the insert material, the intermediate product, and the low melting point metal has the same diameter.

The shape of at least one of the high melting point metal, the insert material, the intermediate product, and the low melting point metal is cylindrical and columnar, and the cylindrical inner diameter and the column outer diameter are substantially the same. The semi-melt forging method as described.

3. The half of claim 2, wherein at least one of the shapes of the high melting point metal and the high melting point insert material, the first intermediate product and the low melting point insert material, and the second intermediate product and the low melting point insert material are different shapes. Melt forging method.

3. The half of claim 2, wherein at least one pair of shapes of the high melting point metal and the high melting point insert material, the first intermediate product and the low melting point insert material, and the second intermediate product and the low melting point insert material have the same diameter. Melt forging method.

The shape of at least one of the high melting point metal and the high melting point insert material, the first intermediate product and the low melting point insert material, and the second intermediate product and the low melting point insert material is cylindrical and columnar, and the cylindrical inner diameter and column outer diameter are 3. The semi-molten forging method according to claim 2, wherein the diameters are substantially the same.

The relationship between the initial height h ₀ of the refractory metal and the insert material and the height h after forging of the refractory metal and the insert material is the most of the solid phase ratio f _S when the refractory metal and the insert material are heated. In relation to a small f _smin ,
ln (h ₀ /h)≧1.5×f _smin ²
Refractory metal shaped to satisfy the, thixoforging method according to any one of claims 1, 3-5, which comprises using an insert material.

Intermediate product, initial height h of low melting point metal _０0 Between the intermediate product and the low melting point metal after forging is the solid phase ratio f when the intermediate product and the low melting point metal are heated. _ｓs The smallest f _{ｓｍｉｎsmin} In relation to
ln (h _０0 /H)≧1.5×f _{ｓｍｉｎsmin} ^２2
The semi-molten forging method according to any one of claims 1, 3 to 5, and 9, wherein an intermediate product and a low melting point metal having a shape satisfying the above conditions are used.

Initial height h of high melting point metal and high melting point insert material _０0 Of the high melting point metal and the high melting point insert material after forging h is the solid phase ratio f when the high melting point metal and high melting point insert material are heated. _ｓs The smallest f _{ｓｍｉｎsmin} In relation to
ln (h _０0 /H)≧1.5×f _{ｓｍｉｎsmin} ^２2
The semi-molten forging method according to any one of claims 2 and 6 to 8, wherein a refractory metal or a refractory insert material having a shape satisfying the above requirements is used.

Initial height h of the first intermediate product, low melting point insert _０0 Of the first intermediate product and the low melting point insert material after forging h is the solid phase ratio f when the first intermediate product and the low melting point insert material are heated. _ｓs The smallest f _{ｓｍｉｎsmin} In relation to
ln (h _０0 /H)≧1.5×f _{ｓｍｉｎsmin} ^２2
The semi-molten forging method according to any one of claims 2, 6 to 8, and 11, wherein a first intermediate product and a low insert material having a shape satisfying the above conditions are used.

Second intermediate product, initial height h of low melting point metal _０0 And the second intermediate product, the height h after forging of the low melting point metal, the solid phase ratio f when the second intermediate product and the low melting point metal are heated _ｓs The smallest f _{ｓｍｉｎsmin} In relation to
ln (h _０0 /H)≧1.5×f _{ｓｍｉｎsmin} ^２2
The semi-molten forging method according to any one of claims 2, 6 to 8, 11, and 12, wherein two intermediate products and a low melting point metal having a shape satisfying the requirements are used.

The semi-molten forging method according to any one of claims 1 to 13 , wherein the forming is performed at an average processing speed of 500 mm / s or more.

The semi-molten forging method according to any one of claims 1 to 14, wherein molding is performed at a processing speed of 200 mm / s or more on average using a forging die heated to 200 ° C or higher in advance.

The semi-molten forging method according to any one of claims 1 to 15, wherein a load of 50% or more of the maximum forging load is maintained until the temperature becomes equal to or lower than a solidus temperature after completion of molding.