JP6048805B2 - Direct recycling method for Ni-based single crystal superalloy parts - Google Patents
Direct recycling method for Ni-based single crystal superalloy parts Download PDFInfo
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- 229910000601 superalloy Inorganic materials 0.000 title claims description 282
- 239000013078 crystal Substances 0.000 title claims description 185
- 238000000034 method Methods 0.000 title claims description 81
- 238000004064 recycling Methods 0.000 title claims description 77
- 238000002844 melting Methods 0.000 claims description 90
- 230000008018 melting Effects 0.000 claims description 90
- 229910045601 alloy Inorganic materials 0.000 claims description 64
- 239000000956 alloy Substances 0.000 claims description 64
- 239000011248 coating agent Substances 0.000 claims description 54
- 238000000576 coating method Methods 0.000 claims description 54
- 238000010438 heat treatment Methods 0.000 claims description 45
- 239000000463 material Substances 0.000 claims description 34
- 230000003647 oxidation Effects 0.000 claims description 32
- 238000007254 oxidation reaction Methods 0.000 claims description 32
- 239000000919 ceramic Substances 0.000 claims description 29
- 239000012720 thermal barrier coating Substances 0.000 claims description 29
- 230000032683 aging Effects 0.000 claims description 12
- 239000000758 substrate Substances 0.000 claims description 12
- 238000001556 precipitation Methods 0.000 claims description 10
- 239000011247 coating layer Substances 0.000 claims description 8
- 230000008569 process Effects 0.000 claims description 8
- 230000006378 damage Effects 0.000 claims description 7
- 239000010410 layer Substances 0.000 claims description 7
- 229910000510 noble metal Inorganic materials 0.000 claims description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 179
- 229910052751 metal Inorganic materials 0.000 description 24
- 239000002184 metal Substances 0.000 description 23
- 239000000243 solution Substances 0.000 description 12
- 239000012535 impurity Substances 0.000 description 11
- 230000002093 peripheral effect Effects 0.000 description 10
- 239000000047 product Substances 0.000 description 10
- 238000005266 casting Methods 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 8
- 230000007246 mechanism Effects 0.000 description 8
- 238000012360 testing method Methods 0.000 description 8
- 238000001816 cooling Methods 0.000 description 7
- 150000002739 metals Chemical class 0.000 description 7
- 230000001172 regenerating effect Effects 0.000 description 6
- 238000007711 solidification Methods 0.000 description 6
- 230000008023 solidification Effects 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 5
- 230000007797 corrosion Effects 0.000 description 5
- 238000005260 corrosion Methods 0.000 description 5
- MCMNRKCIXSYSNV-UHFFFAOYSA-N Zirconium dioxide Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 238000005204 segregation Methods 0.000 description 4
- 238000005728 strengthening Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 3
- 239000004020 conductor Substances 0.000 description 3
- 238000005495 investment casting Methods 0.000 description 3
- 239000011241 protective layer Substances 0.000 description 3
- 238000007670 refining Methods 0.000 description 3
- 238000011069 regeneration method Methods 0.000 description 3
- 230000008439 repair process Effects 0.000 description 3
- 229910052702 rhenium Inorganic materials 0.000 description 3
- WUAPFZMCVAUBPE-UHFFFAOYSA-N rhenium atom Chemical compound [Re] WUAPFZMCVAUBPE-UHFFFAOYSA-N 0.000 description 3
- 230000035945 sensitivity Effects 0.000 description 3
- 239000006104 solid solution Substances 0.000 description 3
- 238000009864 tensile test Methods 0.000 description 3
- 230000002411 adverse Effects 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 238000011109 contamination Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000000635 electron micrograph Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 239000002440 industrial waste Substances 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000012423 maintenance Methods 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 230000035882 stress Effects 0.000 description 2
- 239000002699 waste material Substances 0.000 description 2
- 101000912561 Bos taurus Fibrinogen gamma-B chain Proteins 0.000 description 1
- 229910000995 CMSX-10 Inorganic materials 0.000 description 1
- 229910001011 CMSX-4 Inorganic materials 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 208000003351 Melanosis Diseases 0.000 description 1
- 229910001005 Ni3Al Inorganic materials 0.000 description 1
- KJTLSVCANCCWHF-UHFFFAOYSA-N Ruthenium Chemical compound [Ru] KJTLSVCANCCWHF-UHFFFAOYSA-N 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 210000001787 dendrite Anatomy 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- 239000000428 dust Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 238000007667 floating Methods 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000003716 rejuvenation Effects 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 239000004576 sand Substances 0.000 description 1
- 238000005245 sintering Methods 0.000 description 1
- 239000002002 slurry Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 230000003746 surface roughness Effects 0.000 description 1
- 239000000725 suspension Substances 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical compound [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 description 1
- 230000003313 weakening effect Effects 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Description
本発明は、一旦使用したＮｉ基単結晶超合金部品の廃材を用いて、超合金を精製して合金元素を回収することなく、再びＮｉ基単結晶超合金としてジェットエンジンやガスタービンなどのタービン動翼やタービンベーンなどに使用する場合に用いて好適なＮｉ基単結晶超合金部品の直接リサイクル法に関する。 The present invention recycles a turbine such as a jet engine or a gas turbine again as a Ni-based single crystal superalloy without using the waste material of the Ni-based single crystal superalloy parts once used to refine the superalloy and recover the alloy elements. The present invention relates to a direct recycling method for Ni-based single crystal superalloy parts suitable for use in moving blades and turbine vanes.
Ｎｉ基単結晶超合金部品は、例えばジェットエンジンやガスタービンなどのタービン動翼やタービンベーンとして利用されている。例えばジェットエンジンでは、タービン入口ガス温度が１０００℃から１７００℃と、ニッケルの融点１４５３℃や鉄の融点１５３５℃に相当する高い温度となっている。一般にタービン入口ガス温度が高いほどエネルギー効率が高まり、燃料価格の上昇をエンジン効率の向上で相殺している。 Ni-based single crystal superalloy parts are used, for example, as turbine blades and turbine vanes such as jet engines and gas turbines. For example, in a jet engine, the turbine inlet gas temperature is 1000 ° C. to 1700 ° C., which is a high temperature corresponding to a melting point of 1453 ° C. of nickel and a melting point of 1535 ° C. of iron. In general, the higher the turbine inlet gas temperature, the higher the energy efficiency, and the increase in fuel price is offset by the improvement in engine efficiency.
ところで、タービン動翼やタービンベーンは通常、熱遮蔽コーティング及び内部空冷により超合金基材温度を１０００℃以下に抑えて用いるにも関わらず、消耗品として扱われている。例えばジェット機の離陸時に、砂塵などでジェットエンジン部品の熱遮蔽コーティングが剥離すると、タービン動翼やタービンベーンは飛行途中に損傷が進行する。損傷したタービン動翼やタービンベーンは、定期検査時に交換される。交換したタービン動翼やタービンベーンは、損傷が軽度であれば修理（後述する特許文献１、２、３、４で述べられているような再生処理を含む場合もある）し、損傷が重度であれば廃棄している。繰り返し修理はせいぜい数回程度が限度であるため、現在ではすべてのタービン動翼やタービンベーンが最終的には廃棄されている。 By the way, turbine blades and turbine vanes are usually treated as consumables, although the superalloy substrate temperature is suppressed to 1000 ° C. or less by heat shielding coating and internal air cooling. For example, when a jet airplane takes off from the heat shielding coating of a jet engine component due to dust or the like, damage to the turbine blade and turbine vane progresses during the flight. Damaged turbine blades and turbine vanes are replaced during routine inspections. Replaced turbine blades and turbine vanes are repaired if damage is minor (may include regeneration processing as described in Patent Documents 1, 2, 3, and 4 to be described later). If there is, discard it. Since repeated repairs are limited to a few times at the most, all turbine blades and turbine vanes are eventually discarded.
そこで、特許文献１では、クリープ損傷を受けた鋳造多結晶Ｎｉ基超合金製タービン動翼やタービンベーンの再生方法が提案されている。（以降、部品修理を目的として行われる処理を再生、修理不能となった部品を再度部品化することを目的として行われる処理をリサイクルと呼ぶ）また、特許文献２では、高温使用により強度が劣化した場合に、Ｎｉ基単結晶超合金材料に対して完全溶体化熱処理と時効熱処理を行うことで、単結晶材料の余寿命を延長することが提案されている。
特許文献１、２の再生方法は、Ｎｉ基単結晶超合金材料に対して、再生熱処理によって金属組織を再生する方法である。再生熱処理は、劣化した金属ミクロ組織を熱処理のみで元に戻す方法で、溶体化処理によって、劣化した組織をいったん消滅させた後、時効処理によって、再度健全な微細析出組織を再生する。しかし、タービン動翼やタービンベーンの損傷の程度が大きい場合には再生熱処理では対処不可能となり、廃棄するしかなかった。
Therefore, Patent Document 1 proposes a method for regenerating a turbine blade or turbine vane made of a cast polycrystalline Ni-base superalloy that has undergone creep damage. (Hereinafter, the process performed for the purpose of parts repair is regenerated, and the process performed for the purpose of converting parts that have become unrepairable into parts again is referred to as recycling.) Also, in Patent Document 2, the strength deteriorates due to high temperature use. In this case, it has been proposed to extend the remaining life of the single crystal material by performing complete solution heat treatment and aging heat treatment on the Ni-based single crystal superalloy material.
The regeneration methods of Patent Documents 1 and 2 are methods for regenerating a metal structure by regenerative heat treatment for a Ni-based single crystal superalloy material. Regenerative heat treatment is a method in which a deteriorated metal microstructure is restored only by heat treatment, and once the deteriorated structure is extinguished by solution treatment, a healthy fine precipitate structure is regenerated again by aging treatment. However, when the degree of damage to the turbine blades and the turbine vanes is large, it cannot be dealt with by regenerative heat treatment and must be discarded.
さらに、特許文献３では、Ｎｉ基単結晶超合金部品が高温使用により強度劣化した場合に、若返り処理・再生処理・補修を行うに際して、一旦耐熱性の保護層を除去して、腐食層・酸化層・腐食生成物・酸化生成物の除去が行われると共に、耐熱性保護層のクラックも修理される。その後、耐熱性の保護層の再被覆を行なうことが提案されている。
そして、Ｎｉ基単結晶超合金部品では、合金基材の磨耗やクラックに対して、例えば特許文献４に示す方法で、単結晶を維持しながら、磨耗やクラックの補修が行われている。
しかし、最終的に製品寿命が尽きて使用済み廃材になると、特許文献１、２、３、４に提案されたような再生処理では再生不能であり、例えば特許文献５に示す方法で、部品素材から高いコストをかけて一部の高価な元素のみ精製している。精製された元素は、Ｎｉ基超合金の製造に限らず一般的目的で使用されている。
Further, in Patent Document 3, when Ni-based single crystal superalloy parts deteriorate in strength due to high temperature use, when performing rejuvenation treatment / regeneration treatment / repair, the heat-resistant protective layer is once removed, and the corrosion layer / oxidation layer is removed. Removal of layers, corrosion products, and oxidation products is performed, and cracks in the heat-resistant protective layer are also repaired. Thereafter, it has been proposed to recoat the heat-resistant protective layer.
In the Ni-based single crystal superalloy parts, the wear and cracks are repaired against the wear and cracks of the alloy base material, for example, by the method shown in Patent Document 4 while maintaining the single crystal.
However, when the product life ends up and becomes a used waste material, it cannot be regenerated by the regenerating process proposed in Patent Documents 1, 2, 3, and 4. For example, in the method shown in Patent Document 5, Therefore, only some expensive elements are purified at high cost. Refined elements are used not only for the production of Ni-base superalloys but for general purposes.
一般にＮｉ基超合金部品は、不純物元素の混入に対する感受性が高いことが知られている（例えば、非特許文献１参照）。実際、従来の鋳造多結晶タービン動翼やタービンベーンなどでは、再溶解によりリサイクルされた超合金のクリープ特性、熱疲労特性、耐環境特性を保証できなかった。このため、一旦使用したＮｉ基超合金部品の再溶解による、超合金の組成をほぼ維持したままのリサイクルは、製品であるジェットエンジンやガスタービンを所有する航空会社や発電事業者においては、全く行われてこなかった。 In general, it is known that Ni-base superalloy parts are highly sensitive to contamination by impurity elements (see, for example, Non-Patent Document 1). In fact, conventional cast polycrystalline turbine rotor blades and turbine vanes cannot guarantee the creep characteristics, thermal fatigue characteristics, and environmental resistance characteristics of superalloys recycled by remelting. For this reason, recycling of Ni-based superalloy parts once used, while maintaining the composition of the superalloy, is almost impossible for airlines and power generation companies that own product jet engines and gas turbines. It hasn't been done.
Ｎｉ基超合金部品は、タンタル、レニウム、ルテニウム等の高価で希少なレアメタルを含有している場合がある。レアメタルは、価格面の問題ばかりでなく、資源国が偏在しているため、供給先を安定的に確保することが困難な場合がある。このため、新しく製品を製造しようとする場合には、レアメタルの価格変動と供給リスクの影響を受けて、顧客との約定価格で契約した納品時期に当該製品を提供するのが困難な事態がしばしば発生しており(例えば、２００７年のカザフスタンのレニウム輸出停止措置、非特許文献２参照)、価格安定化および安定供給が強く求められている。 Ni-base superalloy parts may contain expensive and rare rare metals such as tantalum, rhenium, and ruthenium. In rare metals, there are cases where it is difficult to secure a stable supply destination because resource countries are unevenly distributed as well as price issues. For this reason, when trying to manufacture a new product, it is often difficult to provide the product at the delivery date contracted with the customer at the contract price due to the price fluctuation of rare metals and the supply risk. There is a strong demand for price stabilization and stable supply (for example, Kazakhstan's rhenium export suspension in 2007, see Non-Patent Document 2).
本発明は上記課題を解決するもので、Ｎｉ基単結晶超合金部品のリサイクルコストの大幅削減とＮｉ基単結晶超合金部品を使用した高効率ガスタービン機関のライフタイムコストの大幅な削減が可能な、Ｎｉ基単結晶超合金部品の直接リサイクル法を提供することを目的とする。 The present invention solves the above problems, and can significantly reduce the recycling cost of Ni-based single crystal superalloy parts and the lifetime cost of a high-efficiency gas turbine engine using Ni-based single crystal superalloy parts. Another object is to provide a direct recycling method for Ni-based single crystal superalloy parts.
すなわち、本発明者らは鋭意研究を行ない、Ｎｉ基超合金において、不純物元素の混入によりタービン動翼やタービンベーンなどに要求されるクリープ特性、熱疲労特性、耐環境特性が維持できなかった理由を考察した。Ｎｉ基超合金では、これら不純物元素の結晶粒界への偏析が結晶粒界の弱化を招き合金強度を低下させることが、タービン動翼やタービンベーンなどに要求されるクリープ特性を維持できない原因である。他方、Ｎｉ基単結晶超合金は不純物元素の偏析サイトとなり強度劣化につながる結晶粒界を持たないことから、不純物元素混入に対してむしろ鈍感である可能性に着目しリサイクル方法の研究を進めた。この結果、ジェットエンジン部品やガスタービン部品を、直接再溶解によりリサイクルする方法を発明した。 That is, the present inventors conducted intensive research, and in the Ni-base superalloy, the reason why the creep characteristics, thermal fatigue characteristics, and environmental resistance characteristics required for turbine rotor blades, turbine vanes, etc. could not be maintained due to the mixing of impurity elements. Was considered. In Ni-base superalloys, segregation of these impurity elements to the grain boundaries leads to weakening of the grain boundaries and a decrease in the alloy strength. This is because the creep characteristics required for turbine blades and turbine vanes cannot be maintained. is there. On the other hand, since the Ni-based single crystal superalloy does not have a grain boundary that leads to segregation sites of impurity elements and leads to strength deterioration, research on recycling methods has been advanced with a focus on the possibility of being insensitive to impurity element contamination. . As a result, the inventors invented a method for recycling jet engine parts and gas turbine parts by direct remelting.
本発明１のＮｉ基単結晶超合金部品のリサイクル方法は、例えば図２に示すように、セラミックを含む遮熱コーティングで被覆されたＮｉ基単結晶超合金部品であって、遮熱コーティングの被覆層が損壊し、又はＮｉ基単結晶超合金基材に損傷が発生した場合の当該Ｎｉ基単結晶超合金部品のリサイクル方法であって、Ｎｉ基単結晶超合金部品のボンドコーティングを含む遮熱コーティングを剥離する工程（Ｓ２０２）と、Ｎｉ基単結晶超合金の融点以上であってセラミックの融点未満の温度で、Ｎｉ基単結晶超合金部品を溶解する工程（Ｓ２０６）と、リサイクルＮｉ基単結晶超合金部品用鋳型の温度をＮｉ基単結晶超合金の溶解温度以上に加熱する工程（Ｓ２０８）と、リサイクルＮｉ基単結晶超合金部品用鋳型に溶解したＮｉ基単結晶超合金を注湯して、Ｎｉ基単結晶超合金を成長させる工程（Ｓ２１０、Ｓ２１２）と、リサイクルＮｉ基単結晶超合金部品用鋳型からリサイクルＮｉ基単結晶超合金部品を取り外す工程（Ｓ２１４）と、を備える。
The Ni-based single crystal superalloy component recycling method of the present invention 1 is a Ni-based single crystal superalloy component coated with a thermal barrier coating containing ceramic, as shown in FIG. A method for recycling a Ni-based single crystal superalloy component when a layer is damaged or a Ni-based single crystal superalloy substrate is damaged, and includes heat-shielding including bond coating of the Ni-based single crystal superalloy component A step of peeling the coating (S202), a step of melting the Ni-based single crystal superalloy component at a temperature higher than the melting point of the Ni-based single crystal superalloy and lower than the melting point of the ceramic ( S206 ), and heating the temperature of the crystal superalloy component mold above the melting temperature of the Ni-based single crystal superalloy (S208), Ni Mototan dissolved in recycle Ni-based single crystal superalloy component mold By pouring the crystal superalloy, step of removing the growing a Ni-based single crystal superalloy (S210, S212), the recycling Ni-based single crystal superalloy component from the recycle Ni-based single crystal superalloy component mold (S214 And).
このように構成された本発明１のＮｉ基単結晶超合金部品のリサイクル方法では、回収したＮｉ基単結晶超合金部品は、その表面に不純物が存在する可能性があり、好ましくは洗浄を行う。ここで、遮熱コーティングの被覆層に生じる損壊には、剥がれ、浮き、欠損、焼結、溶融がある。Ｎｉ基単結晶超合金基材に生じる損傷には、クラック、変形、欠損、腐食、酸化層の生成、腐食生成物の付着、酸化生成物の付着、金属組織劣化、溶融の類型がある。
次に、Ｎｉ基単結晶超合金部品を溶解するが、溶解温度はＮｉ基単結晶超合金の融点以上であってセラミックの融点未満の温度とする。溶解温度の下限値は、Ｎｉ基超合金の融点である１３５０℃付近よりも高い必要があり、実用的な溶解速度が得られる温度、例えば１５００℃〜１６００℃とする。溶解温度の上限値は、セラミックがアルミナの場合の融点２０５０℃やジルコニアの融点２７２０℃よりも低い必要があり、他方で溶解温度を上げ過ぎると合金元素の蒸発が激しくなり組成制御が困難になるため、２０００℃以下が好ましい。溶解温度は、Ｎｉ基単結晶超合金部品の溶解速度が遅すぎないで、かつ、合金元素の蒸発が少なく組成制御が容易な範囲として、１４００℃から１７００℃の範囲がよく、特に好ましくは１５００℃から１６００℃の範囲である。
鋳型は、リサイクルＮｉ基単結晶超合金部品を鋳造するための形状を有する鋳型であって、単結晶部品鋳造にあたっては、Ｎｉ基単結晶超合金の溶解温度以上に加熱しておく。単結晶部品用鋳型温度は、Ｎｉ基単結晶超合金を成長させるのに適した温度がよく、温度が高すぎると凝固の制御が困難になるから、Ｎｉ基超合金の融点と比較して若干高い程度がよく、例えば１４００℃から１６００℃の範囲とし、特に好ましくは１４５０℃から１５００℃の範囲とする。
そして、鋳型に溶解したＮｉ基超合金を注湯して、単結晶部品とする。Ｎｉ基単結晶超合金は、母相であるγ相（Ｎｉ固溶体）中に、好ましくは６０〜７０ｖｏｌ％のγ’相（Ｎｉ３Ａｌを基本組成とするＬ１２規則相）が整合析出したミクロ組織を有し、整合界面が転位の移動を抑止することにより強化している。続いて、鋳型からリサイクルＮｉ基単結晶超合金部品を取り外す。
In the recycling method of the Ni-based single crystal superalloy part of the present invention 1 configured as described above, the recovered Ni-based single crystal superalloy part may have impurities on its surface, and preferably is cleaned. . Here, the damage generated in the coating layer of the thermal barrier coating includes peeling, floating, chipping, sintering, and melting. Examples of damages that occur in the Ni-based single crystal superalloy substrate include cracks, deformation, defects, corrosion, formation of an oxide layer, adhesion of corrosion products, adhesion of oxidation products, deterioration of metal structure, and melting.
Next, the Ni-based single crystal superalloy part is melted, and the melting temperature is set to a temperature equal to or higher than the melting point of the Ni-based single crystal superalloy and lower than the melting point of the ceramic. The lower limit of the melting temperature needs to be higher than around 1350 ° C., which is the melting point of the Ni-base superalloy, and is a temperature at which a practical melting rate can be obtained, for example, 1500 ° C. to 1600 ° C. The upper limit of the melting temperature needs to be lower than the melting point 2050 ° C. when the ceramic is alumina and the melting point 2720 ° C. of zirconia. On the other hand, if the melting temperature is increased too much, the evaporation of alloy elements becomes intense and the composition control becomes difficult. Therefore, 2000 degrees C or less is preferable. The melting temperature is preferably in the range of 1400 ° C. to 1700 ° C., particularly preferably 1500 as the range in which the melting rate of the Ni-based single crystal superalloy parts is not too slow and the alloy elements are less evaporated and the composition control is easy. The range is from 1 ° C to 1600 ° C.
The mold is a mold having a shape for casting a recycled Ni-based single crystal superalloy part. When casting a single crystal part, the mold is heated to a temperature higher than the melting temperature of the Ni-based single crystal superalloy. The mold temperature for single crystal parts is suitable for growing a Ni-based single crystal superalloy. If the temperature is too high, it becomes difficult to control solidification. A high degree is good, for example, a range of 1400 ° C. to 1600 ° C., particularly preferably a range of 1450 ° C. to 1500 ° C.
Then, the Ni-base superalloy dissolved in the mold is poured into a single crystal part . The Ni-based single crystal superalloy has a microstructure in which the γ phase (Ni solid solution) as a parent phase is preferably co-precipitated with 60 to 70 vol% of the γ ′ phase (L12 ordered phase having a basic composition of Ni3Al). However, the matching interface is strengthened by preventing the movement of dislocations. Subsequently, the recycled Ni-based single crystal superalloy part is removed from the mold.
本発明１のＮｉ基単結晶超合金部品のリサイクル方法では、リサイクルに使用するＮｉ基単結晶超合金部品について、ボンドコーティングを含む遮熱コーティングが残留している場合は、これを剥離することで、ボンドコーティングを含む遮熱コーティングに含まれるセラミックス又は金属元素の影響を低減している。
In the recycling method of the Ni-based single crystal superalloy part of the first aspect of the present invention, if a thermal barrier coating including a bond coating remains on the Ni-based single crystal superalloy part used for recycling, it is peeled off. The effect of ceramics or metal elements contained in the thermal barrier coating including the bond coating is reduced.
本発明２のＮｉ基単結晶超合金部品のリサイクル方法は、耐酸化コーティングで被覆されたＮｉ基単結晶超合金部品であって、耐酸化コーティングの被覆層が損壊し、又はＮｉ基単結晶超合金基材に損傷が発生した場合の当該Ｎｉ基単結晶超合金部品のリサイクル方法であって、耐酸化コーティングで被覆されたＮｉ基単結晶超合金部品の耐酸化コーティングを剥離する工程と、Ｎｉ基単結晶超合金の融点以上でＮｉ基単結晶超合金部品を溶解する工程と、リサイクルＮｉ基単結晶超合金部品用鋳型の温度をＮｉ基単結晶超合金の溶解温度以上に加熱する工程と、リサイクルＮｉ基単結晶超合金部品用鋳型に溶解したＮｉ基超合金を注湯して、Ｎｉ基単結晶超合金を成長させる工程と、リサイクルＮｉ基単結晶超合金部品用鋳型からリサイクルＮｉ基単結晶超合金部品を取り外す工程とを備える。
The recycling method of the Ni-based single crystal superalloy part of the present invention 2 is a Ni-based single crystal superalloy part coated with an oxidation-resistant coating, in which the coating layer of the oxidation-resistant coating is damaged, or the Ni-based single crystal superalloy part is A method for recycling the Ni-based single crystal superalloy part when the alloy substrate is damaged, the step of peeling off the oxidation-resistant coating of the Ni-based single crystal superalloy part coated with the oxidation-resistant coating; Melting the Ni-based single crystal superalloy part at a melting point of the base single-crystal superalloy or higher, heating the recycled Ni-base single crystal superalloy part mold temperature to a temperature higher than the melting temperature of the Ni-based single crystal superalloy, and , resizer a Ni-base superalloy was dissolved in recycle Ni-based single crystal superalloy component mold by pouring, growing an Ni-based single crystal superalloy, from recycled Ni-based single crystal superalloy component mold And a step of removing the Le Ni-based single crystal superalloy component.
好ましくは、本発明３のリサイクルＮｉ基単結晶超合金部品は、さらに、Ｎｉ基単結晶超合金部品の溶体化処理と時効析出処理を行う工程（Ｓ１２２、Ｓ１２４）を有するとよい。溶体化処理は、合金の強化相であるγ’相が、好ましくは完全に固溶体に溶解する温度以上に加熱して、十分な時間保持し均質化を行うと共に、急冷して粗大なγ’相の析出を阻止する熱処理をいう。溶体化処理では、例えば、１２５０℃〜１３８０℃で０．５時間乃至２０時間の熱処理後空冷する。時効析出処理は、硬さ、強さ又は耐食性などを増進させるために適切な温度で、溶体化処理（固溶化熱処理）済の製品を好ましくは均熱保持する熱処理をいう。時効処理として、例えば、１０５０℃〜１１５０℃で５時間乃至１０時間程度保持し、空冷した後、さらに例えば８５０℃〜９００℃で２０時間保持した後空冷の２段階熱処理を施す。
Preferably, the recycled Ni-based single crystal superalloy component according to the third aspect of the present invention may further include a step (S122, S124) of performing solution treatment and aging precipitation treatment of the Ni-based single crystal superalloy component. In the solution treatment, the γ ′ phase that is the strengthening phase of the alloy is preferably heated to a temperature higher than the temperature at which it completely dissolves in the solid solution, held for a sufficient period of time, homogenized, and rapidly cooled to obtain a coarse γ ′ phase. It refers to a heat treatment that prevents the precipitation of. In the solution treatment, for example, air cooling is performed after heat treatment at 1250 ° C. to 1380 ° C. for 0.5 to 20 hours. The aging precipitation treatment refers to a heat treatment in which a solution-treated (solution heat-treated) product is preferably kept soaked at an appropriate temperature in order to enhance hardness, strength, corrosion resistance, or the like. As the aging treatment, for example, after holding at 1050 ° C. to 1150 ° C. for about 5 hours to 10 hours and air cooling, for example, holding at 850 ° C. to 900 ° C. for 20 hours and then air cooling is performed.
好ましくは、本発明４のＮｉ基単結晶超合金部品のリサイクル方法は、さらに、リサイクルＮｉ基単結晶超合金部品を、ボンドコーティングおよびセラミックを含む遮熱コーティングで被覆する工程または耐酸化コーティングで被覆する工程（Ｓ１２６）を有するとよい。遮熱コーティングは、熱伝導率の低いセラミックスのトップコートと、基材の酸化を防止するボンドコーティングよりなる。ボンドコーティングには、Ａｌを多く含む金属コーティングや、耐酸化性と基材に対する拡散を抑制した平衡コーティング等が用いられる。
Preferably, the method for recycling a Ni-based single crystal superalloy part according to the fourth aspect of the present invention further includes a step of coating the recycled Ni-based single crystal superalloy part with a thermal barrier coating including a bond coating and a ceramic or an oxidation resistant coating. It is good to have a process (S126) to do. The thermal barrier coating is composed of a ceramic top coat having low thermal conductivity and a bond coating for preventing oxidation of the substrate. As the bond coating, a metal coating containing a large amount of Al, an equilibrium coating that suppresses oxidation resistance and diffusion to the base material, or the like is used.
好ましくは、本発明５のＮｉ基単結晶超合金部品のリサイクル方法は、Ｎｉ基単結晶超合金のタービン動翼、タービンベーン、燃焼器ライナー、スプラッシュプレート、ダクトセグメント、又はタービンディスクの少なくとも一種類に用いるとよい。
Preferably, the recycling method of the Ni-based single crystal superalloy component of the present invention 5 is at least one of a Ni-based single crystal superalloy turbine blade, turbine vane, combustor liner, splash plate, duct segment, or turbine disk. It is good to use for.
本発明のリサイクル方法の原理は、結晶粒界を有さず不純物元素の粒界偏析を原理的に起こさない単結晶合金では合金強度の不純物感受性が低下するという性質であり、他の合金系やセラミックスにも同様に適用可能である。
好ましくは、本発明６のＮｉ基単結晶超合金部品のリサイクル方法は、本発明１乃至５の何れか１に記載のＮｉ基合金に代えて、Ｃｏ基合金、Ｃｒ基合金、Ｆｅ基合金、Ｎｂ基合金、Ｔａ基合金、Ｗ基合金、Ｍｏ基合金、貴金属基合金、各種セラミックスの少なくとも一種類よりなる単結晶材料を用いるとよい。
The principle of the recycling method of the present invention is that the single-crystal alloy that does not have grain boundaries and does not cause grain boundary segregation of impurity elements in principle has the property that the impurity sensitivity of the alloy strength is reduced. The same applies to ceramics.
Preferably, the recycling method of the Ni-based single crystal superalloy part according to the present invention 6 replaces the Ni-based alloy according to any one of the present inventions 1 to 5 with a Co-based alloy, a Cr-based alloy, an Fe-based alloy, A single crystal material made of at least one of Nb-based alloy, Ta-based alloy, W-based alloy, Mo-based alloy, noble metal-based alloy, and various ceramics may be used.
主応力方向に結晶粒界を有さない一方向凝固材についても、主応力方向の合金強度の不純物感受性が低下するという性質が生かせるため、本発明のリサイクル方法が適用可能である。
本発明７のＮｉ基一方向凝固超合金部品のリサイクル方法は、例えば図５に示すように、セラミックを含む遮熱コーティングで被覆されたＮｉ基一方向凝固超合金部品であって、遮熱コーティングの被覆層が損壊し、又はＮｉ基一方向凝固超合金基材に損傷が発生した場合の当該Ｎｉ基一方向凝固超合金部品のリサイクル方法であって、Ｎｉ基一方向凝固超合金部品のボンドコーティングを含む遮熱コーティングを剥離する工程（Ｓ４０２）と、Ｎｉ基一方向凝固超合金の融点以上であってセラミックの融点未満の温度で、Ｎｉ基一方向凝固超合金部品を溶解する工程（Ｓ４０６）と、リサイクルＮｉ基一方向凝固超合金部品用鋳型の温度をＮｉ基一方向凝固超合金の溶解温度以上に加熱する工程（Ｓ４０８）と、リサイクルＮｉ基一方向凝固超合金部品用鋳型に溶解したＮｉ基超合金を注湯して、Ｎｉ基一方向凝固超合金を成長させる工程（Ｓ４１０、Ｓ４１２）と、リサイクルＮｉ基一方向凝固超合金部品用鋳型からリサイクルＮｉ基一方向凝固超合金部品を取り外す工程（Ｓ４１４）とを備える。
The recycle method of the present invention can also be applied to a unidirectionally solidified material that does not have a grain boundary in the main stress direction, since the property of reducing the impurity sensitivity of the alloy strength in the main stress direction can be utilized.
The method for recycling the Ni-based unidirectionally solidified superalloy component according to the present invention 7 is a Ni-based unidirectionally solidified superalloy component coated with a thermal barrier coating containing ceramic, as shown in FIG. Is a method for recycling the Ni-based unidirectionally solidified superalloy part when the Ni-based unidirectionally solidified superalloy base material is damaged, wherein the Ni-based unidirectionally solidified superalloy part is bonded. Removing the thermal barrier coating including the coating (S402), and melting the Ni-based unidirectionally solidified superalloy component at a temperature equal to or higher than the melting point of the Ni-based unidirectionally solidified superalloy and lower than the melting point of the ceramic ( S406). and), and step (S408) for heating the temperature of the recycle Ni-base directionally solidified superalloy component mold above the melting temperature of the Ni-base directionally solidified superalloy, while recycling Ni group Coagulated by pouring the Ni-base superalloy was dissolved in superalloy component mold, and growing a Ni-base directionally solidified superalloy (S410, S412), recycled from the recycle Ni-base directionally solidified superalloy components mold Removing the Ni-based unidirectionally solidified superalloy component ( S414 ).
本発明８のＮｉ基一方向凝固超合金部品のリサイクル方法は、耐酸化コーティングで被覆されたＮｉ基一方向凝固超合金部品であって、耐酸化コーティングの被覆層が損壊し、又はＮｉ基一方向凝固超合金基材に損傷が発生した場合の当該Ｎｉ基一方向凝固超合金部品のリサイクル方法であって、耐酸化コーティングで被覆されたＮｉ基一方向凝固超合金部品の耐酸化コーティングを剥離する工程と、Ｎｉ基一方向凝固超合金の融点以上でＮｉ基一方向凝固超合金部品を溶解する工程と、リサイクルＮｉ基一方向凝固超合金部品用鋳型の温度をＮｉ基一方向凝固超合金の溶解温度以上に加熱する工程と、リサイクルＮｉ基一方向凝固超合金部品用鋳型に溶解したＮｉ基超合金を注湯して、Ｎｉ基一方向凝固超合金を成長させる工程と、リサイクルＮｉ基一方向凝固超合金部品用鋳型からリサイクルＮｉ基一方向凝固超合金部品を取り外す工程とを備える。
The recycling method of the Ni-based unidirectionally solidified superalloy component of the present invention 8 is a Ni-based unidirectionally solidified superalloy component coated with an oxidation resistant coating, wherein the coating layer of the oxidation resistant coating is damaged or the Ni Recycling method for Ni-based unidirectionally solidified superalloy parts when directionally solidified superalloy base material is damaged , peeling off oxidation-resistant coating on Ni-based unidirectionally solidified superalloy parts coated with oxidation-resistant coating The step of melting the Ni-based unidirectionally solidified superalloy component at a melting point of the Ni-based unidirectionally solidified superalloy, and the temperature of the recycled Ni-based unidirectionally solidified superalloy component mold to the Ni-based unidirectionally solidified superalloy. a step of heating above the melting temperature of the, by pouring a Ni-base superalloy was dissolved in recycle Ni-base directionally solidified superalloy component mold, a step of growing a Ni-base directionally solidified superalloy, Lisa And a step of removing the recycling Ni-base directionally solidified superalloy component from cycle Ni-base directionally solidified superalloy component mold.
好ましくは、本発明９のＮｉ基一方向凝固超合金部品のリサイクル方法は、さらに、リサイクルＮｉ基一方向凝固超合金部品の溶体化処理と時効析出処理を行う工程（Ｓ３２２、Ｓ３２４）を有するとよい。
Preferably, the recycling method of the Ni-based unidirectionally solidified superalloy component of the present invention 9 further includes a step (S322, S324) of performing solution treatment and aging precipitation treatment of the recycled Ni-based unidirectionally solidified superalloy component. Good.
好ましくは、本発明１０のＮｉ基一方向凝固超合金部品のリサイクル方法は、さらに、リサイクルＮｉ基単結晶超合金部品を、ボンドコーティングおよびセラミックを含む遮熱コーティングで被覆する工程または耐酸化コーティングで被覆する工程を有するとよい。
Preferably, the recycling method of the Ni-based unidirectionally solidified superalloy component of the present invention 10 further includes a step of coating the recycled Ni-based single crystal superalloy component with a thermal barrier coating including a bond coating and a ceramic, or an oxidation resistant coating. It is good to have a process of covering.
好ましくは、本発明１１のＮｉ基一方向凝固超合金部品のリサイクル方法は、Ｎｉ基一方向凝固超合金のタービン動翼、タービンベーン、燃焼器ライナー、スプラッシュプレート、ダクトセグメント、又はタービンディスクの少なくとも一種類に用いるとよい。
Preferably, the recycling method of the Ni-based unidirectionally solidified superalloy component of the present invention 11 includes at least a Ni-based unidirectionally solidified superalloy turbine blade, turbine vane, combustor liner, splash plate, duct segment, or turbine disk. It is good to use for one kind.
好ましくは、本発明１２のＮｉ基一方向凝固超合金部品のリサイクル方法は、本発明７乃至１１の何れか１に記載のＮｉ基合金に代えて、Ｃｏ基合金、Ｃｒ基合金、Ｆｅ基合金、Ｎｂ基合金、Ｔａ基合金、Ｗ基合金、Ｍｏ基合金、貴金属基合金、各種セラミックスの少なくとも一種類よりなる一方向凝固材料を用いるとよい。 Preferably, the recycling method of the Ni-based unidirectionally solidified superalloy component according to the present invention 12 is replaced with the Ni-based alloy according to any one of the present inventions 7 to 11 in place of a Co-based alloy, a Cr-based alloy, and an Fe-based alloy. A unidirectionally solidified material made of at least one of Nb-based alloy, Ta-based alloy, W-based alloy, Mo-based alloy, noble metal-based alloy, and various ceramics may be used.
本発明のＮｉ基単結晶超合金部品の直接再溶解によるリサイクル方法は、従来の特許文献５に示す精製による合金元素回収リサイクル方法よりもはるかに低コストである。そこで、Ｎｉ基単結晶超合金部品のライフタイムコストが低下し、製造コストが普通鋳造合金や一方向凝固と比較して高くても、リサイクルコストが低廉であるため、Ｎｉ基単結晶超合金部品の普及が促進される。 The recycling method by direct remelting of the Ni-based single crystal superalloy component of the present invention is much lower in cost than the conventional alloy element recovery and recycling method by refining shown in Patent Document 5. Therefore, Ni-based single crystal superalloy parts have lower lifetime costs, and even though manufacturing costs are higher than ordinary casting alloys or unidirectional solidification, recycling costs are low. Will be promoted.
また、既に製造済みのＮｉ基単結晶超合金部品が、レアメタルの損耗なくリサイクルできるので、レアメタルの供給先確保の問題が緩和されると共に、超合金を精製して合金元素を回収する場合に多量に発生する産業廃棄物処理の問題も緩和される利点がある。さらに、本発明のＮｉ基単結晶超合金部品のリサイクル方法の普及によって、レアメタル需要と価格が安定するため、ガスタービンの高効率化に必須のＮｉ基単結晶超合金部品の普及が促進される。
また、本発明のＮｉ基単結晶超合金部品の直接再溶解によるリサイクル方法は、Ｎｉ基一方向凝固超合金部品にも同様に適用される。
In addition, since Ni-based single crystal superalloy parts that have already been manufactured can be recycled without wear and tear of rare metals, the problem of securing rare metal suppliers is alleviated, and a large amount is required when refining superalloys and recovering alloy elements. There is an advantage that the problem of the industrial waste treatment that occurs in the country is also alleviated. Furthermore, the popularization of the recycling method for Ni-based single crystal superalloy parts of the present invention stabilizes the demand and price of rare metals, and therefore promotes the popularization of Ni-based single crystal superalloy parts essential for high efficiency of gas turbines. .
The recycling method by direct remelting of the Ni-based single crystal superalloy part of the present invention is similarly applied to Ni-based unidirectionally solidified superalloy parts.
以下、図面を用いて本発明を説明する。
図１は、真空高周波溶解装置の概略構成図である。図において、真空高周波溶解装置は、溶湯るつぼ１０、鋳型加熱炉２０、鋳型３０、鋳型昇降機構（図示せず）、及び真空容器５０を有している。
溶湯るつぼ１０は、Ｎｉ基単結晶超合金部品を溶解するためのるつぼで、アルミナ、ジルコニアなどのセラミックを素材としたるつぼが使用される。溶湯るつぼ１０は、例えば注ぎ口を有するコップ形状をしており、外周部に加熱用の高周波コイル１２が設けられている。誘導加熱は、交流電源につながれたコイルの中に導体を挿入すると、コイルと導体は非接触にもかかわらず、導体が表面から加熱される現象を用いる加熱方法で、うず電流と導体の電気抵抗で発生するジュール熱を用いている。
Hereinafter, the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a vacuum high-frequency melting apparatus. In the figure, the vacuum high-frequency melting apparatus has a molten crucible 10, a mold heating furnace 20, a mold 30, a mold lifting mechanism (not shown), and a vacuum vessel 50.
The molten metal crucible 10 is a crucible for melting Ni-based single crystal superalloy parts, and a crucible made of ceramic such as alumina or zirconia is used. The molten crucible 10 has, for example, a cup shape having a spout, and a heating high-frequency coil 12 is provided on the outer peripheral portion. Induction heating is a heating method that uses a phenomenon in which when a conductor is inserted into a coil connected to an AC power source, the coil and conductor are not in contact with each other, but the conductor is heated from the surface. The Joule heat generated in is used.
鋳型加熱炉２０は、溶湯受け口２１、蓋部断熱部２２、蓋部発熱部２３、周壁高周波コイル２４、周壁断熱部２５、周壁発熱部２６、底周縁発熱部２７、底周縁断熱部２８、底面断熱部２９を有している。溶湯受け口２１は、溶湯るつぼ１０から注がれる溶湯を、鋳型３０に注ぎ込むための案内部である。蓋部発熱部２３、周壁発熱部２６、底周縁発熱部２７は、鋳型加熱炉２０の炉内温度を溶湯が維持される温度に加熱するための発熱体で、周壁高周波コイル２４による誘導加熱を用いている。蓋部断熱部２２、周壁断熱部２５、底周縁断熱部２８、底面断熱部２９は、鋳型加熱炉２０の炉内に設置される鋳型３０をＮｉ基単結晶超合金の溶解温度に保持するために用いる。 The mold heating furnace 20 includes a molten metal inlet 21, a lid heat insulating part 22, a lid heat generating part 23, a peripheral wall high-frequency coil 24, a peripheral wall heat insulating part 25, a peripheral wall heat generating part 26, a bottom peripheral heat generating part 27, a bottom peripheral heat insulating part 28, and a bottom surface. A heat insulating portion 29 is provided. The molten metal receiving port 21 is a guide part for pouring the molten metal poured from the molten metal crucible 10 into the mold 30. The lid heating unit 23, the peripheral wall heating unit 26, and the bottom edge heating unit 27 are heating elements for heating the temperature inside the mold heating furnace 20 to a temperature at which the molten metal is maintained, and induction heating by the peripheral wall high-frequency coil 24 is performed. Used. The lid heat insulating part 22, the peripheral wall heat insulating part 25, the bottom peripheral heat insulating part 28, and the bottom heat insulating part 29 are for maintaining the mold 30 installed in the furnace of the mold heating furnace 20 at the melting temperature of the Ni-based single crystal superalloy. Used for.
鋳型３０は、メルティングストック又はリサイクルＮｉ基単結晶超合金部品を鋳造するための形状を有する鋳型であって、単結晶部品用鋳型はＮｉ基単結晶超合金の溶解温度以上に加熱しておく。メルティングストック用の場合は、鋳型３０は通常の砂型でよいが、精密鋳造法やロストワックス法を用いてもよい。タービン動翼やタービンベーン用の場合では、出来上がった製品に格段に寸法精度、表面粗さが要求されるために、鋳型３０は例えばロストワックス法のような精密鋳造法を用いて製作される。精密鋳造法は鋳型に金型を用いない方法で、鋳型材料を流動性のよいスラリーとすることで、模型の複雑な形状を鋳造できる。ロストワックス法は、模型にろうを用い、模型を複数の耐火物層で包んだ後、模型のろうを溶出又は焼却して鋳型を作る方法である。 The mold 30 is a mold having a shape for casting a melting stock or a recycled Ni-based single crystal superalloy part, and the mold for the single crystal part is heated to a temperature higher than the melting temperature of the Ni-based single crystal superalloy. . In the case of a melting stock, the mold 30 may be a normal sand mold, but a precision casting method or a lost wax method may be used. In the case of turbine blades and turbine vanes, the mold 30 is manufactured using a precision casting method such as the lost wax method because the finished product is required to have dimensional accuracy and surface roughness. The precision casting method is a method in which a mold is not used as a mold, and a complicated shape of a model can be cast by making a mold material into a slurry having good fluidity. The lost wax method is a method in which a wax is used as a model, the model is wrapped with a plurality of refractory layers, and then the mold wax is eluted or incinerated to make a mold.
セレクタ部３２は、直径数ｍｍ程度の細長い管で、鋳型３０とチルプレート（冷却板）３８の間に設けられており、一つの結晶方位だけを選択して成長させて、Ｎｉ基超合金の単結晶とする。鋳型内溶湯部３４は、鋳型３０内のＮｉ基超合金の溶湯である。基部凝固部３６は、チルプレート３８によって凝固したリサイクルＮｉ基単結晶超合金部品の基部である。チルプレート３８は、例えば水冷銅盤を用いる。 The selector unit 32 is an elongated tube having a diameter of several millimeters, and is provided between the mold 30 and the chill plate (cooling plate) 38. Only one crystal orientation is selected and grown, and a Ni-based superalloy is formed. Single crystal. The in-mold molten metal portion 34 is a molten Ni-base superalloy in the mold 30. The base solidified part 36 is a base part of a recycled Ni-based single crystal superalloy part solidified by the chill plate 38. For the chill plate 38, for example, a water-cooled copper disk is used.
鋳型昇降機構は、チルプレート３８に乗った鋳型３０を昇降する。単結晶凝固したリサイクルＮｉ基単結晶超合金部品は、鋳型加熱炉から鋳型を下方に引出し、ふく射放熱で冷却し、下部から上方に向かって凝固させる改良ブリッジマン法で製造される。冷却には、気体または液体と接触させることによる伝導冷却を併用しても良い。真空容器５０は、溶湯るつぼ１０、鋳型加熱炉２０、鋳型３０、鋳型昇降機構を収容する密閉容器で、リサイクルＮｉ基単結晶超合金部品の鋳造を全て真空中で行なうことができる。 The mold lifting mechanism moves the mold 30 on the chill plate 38 up and down. Single-crystal solidified recycled Ni-based single crystal superalloy parts are manufactured by an improved Bridgman method in which a mold is drawn downward from a mold heating furnace, cooled by radiation heat radiation, and solidified upward from the bottom. For cooling, conduction cooling by contacting with gas or liquid may be used together. The vacuum vessel 50 is a sealed vessel that accommodates the molten metal crucible 10, the mold heating furnace 20, the mold 30 and the mold lifting mechanism, and can perform casting of recycled Ni-based single crystal superalloy parts in a vacuum.
リサイクルＮｉ基単結晶超合金部品の凝固組織は、固液界面の温度勾配と凝固速度の組み合わせに影響される。健全な単結晶組織を経済的に実現させるためには高速凝固法を採用する。この組み合わせを適正にすることで、粒界割れや等軸晶が発生せず、デンドライト間隔が細かい組織を得る。
リサイクルＮｉ基単結晶超合金部品の鋳造では、温度勾配が小さいと、異結晶やフレッケル等の欠陥が発生するため、凝固界面での温度勾配をできるだけ大きくして、単結晶を安定して成長させる。
The solidification structure of recycled Ni-based single crystal superalloy parts is affected by the combination of the temperature gradient at the solid-liquid interface and the solidification rate. In order to achieve a sound single crystal structure economically, a high-speed solidification method is adopted. By making this combination appropriate, a grain boundary crack and an equiaxed crystal do not occur, and a structure having a fine dendrite interval is obtained.
When casting recycled Ni-based single crystal superalloy parts, defects such as heterocrystals and freckle occur when the temperature gradient is small. Therefore, the temperature gradient at the solidification interface is increased as much as possible to stably grow the single crystal. .
このように構成された真空高周波溶解装置を用いて、リサイクルＮｉ基単結晶超合金部品を製造する方法を次に説明する。
図２は、本発明のＮｉ基単結晶超合金部品のリサイクル方法を説明する流れ図で、図１の装置を用いる場合を示している。まず、リサイクル対象となるＮｉ基単結晶超合金部品を用意する（Ｓ１００）。このリサイクル対象部品は、以下の類型のものである。
（ｉ）セラミックを含む遮熱コーティングで被覆されたＮｉ基単結晶超合金部品であって、遮熱コーティングの被覆層が損壊し、又はＮｉ基単結晶超合金基材に損傷が発生したもの、
（ｉｉ）耐酸化コーティングが被覆されたＮｉ基単結晶超合金部品であって、耐酸化コーティングの被覆層が損壊し、またはＮｉ基単結晶超合金基材に損傷が発生したもの、
（ｉｉｉ）コーティングされていないＮｉ基単結晶超合金部品であって、Ｎｉ基単結晶超合金基材に損傷が発生したもの、
（ｉｖ）上記（ｉ）〜（ｉｉｉ）に該当するものであって、ガスタービンでの継続使用が技術的・経済的に困難なもの、または修理するよりも本特許に示されているリサイクル法を用いる方が経済的に優位であると判断されるものである。
Next, a method of manufacturing a recycled Ni-based single crystal superalloy part using the vacuum high-frequency melting apparatus configured as described above will be described.
FIG. 2 is a flowchart for explaining the recycling method of the Ni-based single crystal superalloy part according to the present invention, and shows a case where the apparatus of FIG. 1 is used. First, a Ni-based single crystal superalloy part to be recycled is prepared (S100). The parts to be recycled are of the following types.
(I) a Ni-based single crystal superalloy part coated with a thermal barrier coating containing ceramic, wherein the coating layer of the thermal barrier coating is damaged or the Ni-based single crystal superalloy substrate is damaged;
(Ii) a Ni-based single crystal superalloy part coated with an oxidation-resistant coating, wherein the coating layer of the oxidation-resistant coating is damaged or the Ni-based single crystal superalloy substrate is damaged,
(Iii) a non-coated Ni-based single crystal superalloy part, wherein the Ni-based single crystal superalloy substrate is damaged,
(Iv) Recycling methods that fall under the above (i) to (iii) and that are technically and economically difficult to use continuously in a gas turbine, or that are shown in this patent rather than being repaired It is judged that it is economically superior to use.
まず、リサイクル対象部品であるＮｉ基単結晶超合金部品の表面を好ましくは洗浄する（Ｓ１０２）。そしてリサイクル対象部品を乾燥させる。次に、リサイクル対象部品を溶湯るつぼ１０に投入して、Ｎｉ基単結晶超合金の融点以上であってセラミックの融点未満の温度で、Ｎｉ基単結晶超合金部品を溶解する（Ｓ１０４）。他方で、メルティングストック用鋳型またはリサイクルＮｉ基単結晶超合金部品用鋳型３０を鋳型加熱炉２０内に置き、鋳型加熱炉２０によって鋳型３０の温度をＮｉ基単結晶超合金の溶解温度以上に加熱する（Ｓ１０６）。そして、溶湯るつぼ１０の溶解したＮｉ基超合金を鋳型３０に注湯する（Ｓ１０８）。鋳型昇降機構とチルプレート３８を用いて、鋳型３０内でＮｉ基単結晶超合金を成長させる（Ｓ１１０）。そして、鋳型３０からリサイクルＮｉ基単結晶超合金部品を取り外す（Ｓ１１２）。メルティングストックへとリサイクルする場合は、上記鋳型加熱工程（Ｓ１０６）と単結晶成長工程（Ｓ１１０）を省略し、凝固したメルティングストックを取り出す（Ｓ１１２）ことができる。 First, the surface of a Ni-based single crystal superalloy part that is a part to be recycled is preferably cleaned (S102). Then, the parts to be recycled are dried. Next, the parts to be recycled are put into the molten crucible 10 and the Ni-based single crystal superalloy parts are melted at a temperature not lower than the melting point of the Ni-based single crystal superalloy and lower than the melting point of the ceramic (S104). On the other hand, a mold for melting stock or a mold 30 for recycled Ni-based single crystal superalloy parts is placed in the mold heating furnace 20, and the temperature of the mold 30 is set to be equal to or higher than the melting temperature of the Ni-based single crystal superalloy by the mold heating furnace 20. Heat (S106). Then, the molten Ni-base superalloy in the molten crucible 10 is poured into the mold 30 (S108). A Ni-based single crystal superalloy is grown in the mold 30 using the mold lifting mechanism and the chill plate 38 (S110). Then, the recycled Ni-based single crystal superalloy component is removed from the mold 30 (S112). In the case of recycling to the melting stock, the mold heating step (S106) and the single crystal growth step (S110) can be omitted, and the solidified melting stock can be taken out (S112).
なお、リサイクル対象部品を前処理してもよい。すなわち、リサイクル対象部品の遮熱コーティングを剥離し（Ｓ２０２）、次にリサイクル対象部品の表面を洗浄する（Ｓ２０４）。続いて、上述のＳ１０４〜Ｓ１１２と同様の処理を続ける。即ち、リサイクル対象部品を溶湯るつぼ１０に投入して、Ｎｉ基単結晶超合金の融点以上でＮｉ基単結晶超合金部品を溶解する（Ｓ２０６）。他方で、メルティングストック用鋳型またはリサイクルＮｉ基単結晶超合金部品用鋳型３０を鋳型加熱炉２０内に置き、鋳型加熱炉２０によって鋳型３０の温度をＮｉ基単結晶超合金の溶解温度以上に加熱する（Ｓ２０８）。そして、溶湯るつぼ１０の溶解したＮｉ基超合金を鋳型３０に注湯する（Ｓ２１０）。鋳型昇降機構とチルプレート３８を用いて、鋳型３０内でＮｉ基単結晶超合金を成長させる（Ｓ２１２）。そして、鋳型３０からリサイクルＮｉ基単結晶超合金部品を取り外す（Ｓ２１４）。メルティングストックへとリサイクルする場合は、上記鋳型加熱工程（Ｓ２０８）と単結晶成長工程（Ｓ２１２）を省略し、凝固したメルティングストックを取り出す（Ｓ２１４）ことができる。 Note that the parts to be recycled may be pretreated. That is, the thermal barrier coating of the part to be recycled is peeled off (S202), and then the surface of the part to be recycled is cleaned (S204). Subsequently, processing similar to that in S104 to S112 described above is continued. That is, the parts to be recycled are put into the molten crucible 10 and the Ni-based single crystal superalloy parts are melted at a temperature equal to or higher than the melting point of the Ni-based single crystal superalloy (S206). On the other hand, a mold for melting stock or a mold 30 for recycled Ni-based single crystal superalloy parts is placed in the mold heating furnace 20, and the temperature of the mold 30 is set to be equal to or higher than the melting temperature of the Ni-based single crystal superalloy by the mold heating furnace 20. Heat (S208). Then, the molten Ni-base superalloy in the molten crucible 10 is poured into the mold 30 (S210). A Ni-based single crystal superalloy is grown in the mold 30 using the mold lifting mechanism and the chill plate 38 (S212). Then, the recycled Ni-based single crystal superalloy component is removed from the mold 30 (S214). In the case of recycling to the melting stock, the mold heating step (S208) and the single crystal growth step (S212) can be omitted, and the solidified melting stock can be taken out (S214).
このようにすると、リサイクル対象部品の遮熱コーティングの材質が、メルティングストックまたはリサイクルＮｉ基単結晶超合金部品の性質に悪影響を与える場合でも、当該影響を少なくできる。このリサイクル方法では、ボンドコーティングを除く遮熱コーティングもしくはボンドコーティングを含む遮熱コーティングを剥離しても良く、また、耐酸化コーティングのみを施してあるＮｉ基単結晶超合金部品にそのまま、もしくは耐酸化コーティングを剥離して適用しても良く、コーティングされていないＮｉ基単結晶超合金部品にそのまま適用しても良い。 In this way, even when the material of the thermal barrier coating of the part to be recycled adversely affects the properties of the melting stock or the recycled Ni-based single crystal superalloy part, the influence can be reduced. In this recycling method, the thermal barrier coating excluding the bond coating or the thermal barrier coating including the bond coating may be peeled off, or the Ni-based single crystal superalloy part having only the oxidation-resistant coating applied as it is or in an oxidation-resistant manner. The coating may be peeled off and applied, or may be applied as it is to an uncoated Ni-based single crystal superalloy part.
メルティングストックへとリサイクルする場合には、Ｓ１１２やＳ２１４で出来上がったメルティングストックを貯蔵する（Ｓ１１４、Ｓ２１６）。メルティングストックよりリサイクルＮｉ基単結晶超合金部品を製造するには、目的とするタービン動翼やタービンベーンなどの形状に対応した鋳型を準備して、真空高周波溶解装置を用いて、再度溶湯るつぼ１０で溶解して（Ｓ１２０）、一方向凝固させて単結晶とする。 In the case of recycling to the melting stock, the melting stock completed in S112 and S214 is stored (S114, S216). To manufacture recycled Ni-based single crystal superalloy parts from the melting stock, prepare a mold corresponding to the shape of the target turbine rotor blade or turbine vane, etc., and use the vacuum high-frequency melting device to re-melt the crucible. 10 (S120) and solidify in one direction to form a single crystal.
リサイクルＮｉ基単結晶超合金部品が、Ｎｉ基単結晶超合金のタービン動翼やタービンベーンなどの場合には、リサイクルＮｉ基単結晶超合金部品の溶体化処理を行い（Ｓ１２２）、次に時効析出処理（Ｓ１２４）を行う。この溶体化処理と時効析出処理により、強化相（γ′相）が適切なサイズ・形状になる。続いて、リサイクルＮｉ基単結晶超合金部品を、必要に応じて、セラミックを含む遮熱コーティングもしくは耐酸化コーティングで被覆する（Ｓ１２６）。 When the recycled Ni-based single crystal superalloy part is a turbine blade or turbine vane of Ni-based single crystal superalloy, solution treatment of the recycled Ni-based single crystal superalloy part is performed (S122), and then aging Precipitation processing (S124) is performed. By this solution treatment and aging precipitation treatment, the strengthening phase (γ ′ phase) becomes an appropriate size and shape. Subsequently, the recycled Ni-based single crystal superalloy component is coated with a thermal barrier coating or an oxidation resistant coating containing ceramic as required (S126).
Ｎｉ基単結晶超合金の実施例として、ＰＷＡ１４８４（登録商標）材製のジェットエンジン使用済みＨＰＴ動翼を真空中で直接高周波溶解し、単結晶試験片を鋳造した（以後リサイクル材と呼称する）。比較材として、Ｎｉ基単結晶超合金ＰＷＡ１４８４材の純正メルティングストックを用いて単結晶試験片を鋳造した（以後純正材と呼称する）。
これらを用いて、機械強度比較のための引張試験、高温強度比較のためクリープ試験を行った。結果を表１および表２に示す。クリープ試験の試験片の形状は、図３に示すとおりである。即ち、試験片５０はクリープ試験機に固定するための基部５２と、両端の基部５２に挟まれた中間部５４を有している。中間部５４は、長さＬが２０ｍｍで、直径Ｄが４ｍｍの丸棒形状である。
As an example of a Ni-based single crystal superalloy, a jet engine used HPT rotor blade made of PWA1484 (registered trademark) was directly subjected to high frequency melting in a vacuum, and a single crystal test piece was cast (hereinafter referred to as a recycled material). . As a comparative material, a single crystal test piece was cast using a genuine melting stock of Ni-based single crystal superalloy PWA1484 (hereinafter referred to as a genuine material).
Using these, a tensile test for mechanical strength comparison and a creep test for high temperature strength comparison were performed. The results are shown in Tables 1 and 2. The shape of the specimen for the creep test is as shown in FIG. That is, the test piece 50 has a base portion 52 for fixing to the creep tester and an intermediate portion 54 sandwiched between the base portions 52 at both ends. The intermediate portion 54 has a round bar shape with a length L of 20 mm and a diameter D of 4 mm.
表１の引張試験では、リサイクル材が純正材よりも高い引張強度、伸び、および絞りを示した。表２のクリープ試験では、リサイクル材が純正材よりも高いクリープ寿命、および絞りを示した。また、リサイクル材の伸びは実用上十分な値を示している。これらの結果から、本発明のＮｉ基単結晶超合金部品のリサイクル方法が有効であることが確認された。 In the tensile test of Table 1, the recycled material showed higher tensile strength, elongation and drawing than the genuine material. In the creep test of Table 2, the recycled material showed a higher creep life and drawing than the genuine material. Moreover, the elongation of the recycled material shows a practically sufficient value. From these results, it was confirmed that the recycling method for Ni-based single crystal superalloy parts of the present invention is effective.
図４は、正規材とリサイクル材の比較電子顕微鏡写真で、倍率５０００倍の図である。Ｎｉ基単結晶超合金は母相であるγ相（Ｎｉ固溶体）中にγ’相（Ｌ１２規則相）が整合析出したミクロ組織を有しているが、正規材とリサイクル材でこのミクロ組織に大きな差異は見られない。
なお、実施例に用いたＮｉ基単結晶超合金ＰＷＡ１４８４材は、代表的なＮｉ基単結晶超合金の一つであり、他の類似単結晶超合金、例えばＣＭＳＸ−４（登録商標）、Ｒｅｎｅ−Ｎ６（登録商標）、ＣＭＳＸ−１０（登録商標）等と同様の、添加元素、ミクロ組織、強化機構等を有している。
FIG. 4 is a comparative electron micrograph of a regular material and a recycled material, and is a diagram at a magnification of 5000 times. Ni-based single crystal superalloy has a microstructure gamma phase as a matrix phase (Ni solid solution) in the gamma 'phase (L1 2 ordered phase) is precipitated matched, this microstructure regular material and recycled material There is no significant difference.
The Ni-based single crystal superalloy PWA1484 material used in the examples is one of typical Ni-based single crystal superalloys, and other similar single crystal superalloys such as CMSX-4 (registered trademark), Rene. -It has the same additive element, microstructure, strengthening mechanism, etc. as N6 (registered trademark), CMSX-10 (registered trademark), etc.
続いて、本発明の実施の形態として、リサイクルＮｉ基一方向凝固超合金部品を製造する方法を次に説明する。リサイクルＮｉ基一方向凝固超合金部品は、図１に示した真空高周波溶解装置を用いて製造する。なお、前述の真空高周波溶解装置の説明において、その性質に反しない限り、Ｎｉ基単結晶超合金とあるのをＮｉ基一方向凝固超合金と読み替える。即ち、リサイクルＮｉ基一方向凝固超合金部品用鋳型の形状は、リサイクルＮｉ基単結晶超合金部品用鋳造と比較して、セレクタ部３２の設けられていない点を除いて、同じである。
図５は、本発明のＮｉ基一方向凝固超合金部品のリサイクル方法を説明する流れ図で、図１の装置を用いる場合を示している。まず、リサイクル対象となるＮｉ基一方向凝固超合金部品を用意する（Ｓ３００）。
Subsequently, as an embodiment of the present invention, a method for manufacturing a recycled Ni-based unidirectionally solidified superalloy component will be described below. Recycled Ni-based unidirectionally solidified superalloy parts are manufactured using the vacuum high-frequency melting apparatus shown in FIG. In the description of the vacuum high-frequency melting apparatus described above, the Ni-based single crystal superalloy is replaced with Ni-based unidirectionally solidified superalloy unless it contradicts its properties. That is, the shape of the recycled Ni-based unidirectionally solidified superalloy component mold is the same as that of the recycled Ni-based single crystal superalloy component casting except that the selector portion 32 is not provided.
FIG. 5 is a flowchart for explaining the recycling method of the Ni-based unidirectionally solidified superalloy component of the present invention, and shows a case where the apparatus of FIG. 1 is used. First, a Ni-based unidirectionally solidified superalloy part to be recycled is prepared (S300).
まず、リサイクル対象部品であるＮｉ基一方向凝固超合金部品の表面を好ましくは洗浄する（Ｓ３０２）。そしてリサイクル対象部品を乾燥させる。次に、リサイクル対象部品を溶湯るつぼ１０に投入して、Ｎｉ基一方向凝固超合金の融点以上であってセラミックの融点未満の温度で、Ｎｉ基一方向凝固超合金部品を溶解する（Ｓ３０４）。他方で、メルティングストック用鋳型またはリサイクルＮｉ基一方向凝固超合金部品用鋳型３０を鋳型加熱炉２０内に置き、鋳型加熱炉２０によって鋳型３０の温度をＮｉ基一方向凝固超合金の溶解温度以上に加熱する（Ｓ３０６）。そして、溶湯るつぼ１０の溶解したＮｉ基超合金を鋳型３０に注湯する（Ｓ３０８）。鋳型昇降機構とチルプレート３８を用いて、鋳型３０内でＮｉ基一方向凝固超合金を成長させる（Ｓ３１０）。そして、鋳型３０からリサイクルＮｉ基一方向凝固超合金部品を取り外す（Ｓ３１２）。メルティングストックへとリサイクルする場合は、上記鋳型加熱工程（Ｓ３０６）と単結晶成長工程（Ｓ３１０）を省略し、凝固したメルティングストックを取り出す（Ｓ３１２）ことができる。 First, the surface of the Ni-based unidirectionally solidified superalloy part that is the part to be recycled is preferably cleaned (S302). Then, the parts to be recycled are dried. Next, the parts to be recycled are put into the molten crucible 10 and the Ni-based unidirectionally solidified superalloy parts are melted at a temperature that is equal to or higher than the melting point of the Ni-based unidirectionally solidified superalloy and lower than the melting point of the ceramic (S304). . On the other hand, the melting stock mold or the recycled Ni-based unidirectionally solidified superalloy component mold 30 is placed in the mold heating furnace 20, and the temperature of the mold 30 is changed by the mold heating furnace 20 to the melting temperature of the Ni-based unidirectionally solidified superalloy. Heat to the above (S306). Then, the molten Ni-base superalloy in the molten crucible 10 is poured into the mold 30 (S308). A Ni-based unidirectionally solidified superalloy is grown in the mold 30 using the mold lifting mechanism and the chill plate 38 (S310). Then, the recycled Ni-based unidirectionally solidified superalloy component is removed from the mold 30 (S312). In the case of recycling to the melting stock, the mold heating step (S306) and the single crystal growth step (S310) can be omitted, and the solidified melting stock can be taken out (S312).
なお、リサイクル対象部品を前処理してもよい。すなわち、リサイクル対象部品の遮熱コーティングを剥離し（Ｓ４０２）、次にリサイクル対象部品の表面を洗浄する（Ｓ４０４）。続いて、上述のＳ３０４〜Ｓ３１２と同様の処理を続ける。即ち、リサイクル対象部品を溶湯るつぼ１０に投入して、Ｎｉ基一方向凝固超合金の融点以上でＮｉ基一方向凝固超合金部品を溶解する（Ｓ４０６）。他方で、メルティングストック用鋳型またはリサイクルＮｉ基一方向凝固超合金部品用鋳型３０を鋳型加熱炉２０内に置き、鋳型加熱炉２０によって鋳型３０の温度をＮｉ基一方向凝固超合金の溶解温度以上に加熱する（Ｓ４０８）。そして、溶湯るつぼ１０の溶解したＮｉ基超合金を鋳型３０に注湯する（Ｓ４１０）。鋳型昇降機構とチルプレート３８を用いて、鋳型３０内でＮｉ基一方向凝固超合金を成長させる（Ｓ４１２）。そして、鋳型３０からリサイクルＮｉ基一方向凝固超合金部品を取り外す（Ｓ４１４）。メルティングストックへとリサイクルする場合は、上記鋳型加熱工程（Ｓ４０８）と単結晶成長工程（Ｓ４１２）を省略し、凝固したメルティングストックを取り出す（Ｓ４１４）ことができる。 Note that the parts to be recycled may be pretreated. That is, the thermal barrier coating of the part to be recycled is peeled off (S402), and then the surface of the part to be recycled is cleaned (S404). Subsequently, the same processing as in S304 to S312 described above is continued. That is, the parts to be recycled are put into the molten crucible 10 and the Ni-based unidirectionally solidified superalloy parts are melted at or above the melting point of the Ni-based unidirectionally solidified superalloy (S406). On the other hand, a melting stock mold or a recycled Ni-based unidirectionally solidified superalloy component mold 30 is placed in the mold heating furnace 20, and the temperature of the mold 30 is changed by the mold heating furnace 20 to the melting temperature of the Ni-based unidirectionally solidified superalloy. It heats above (S408). Then, the molten Ni-base superalloy in the molten crucible 10 is poured into the mold 30 (S410). A Ni-based unidirectionally solidified superalloy is grown in the mold 30 using the mold lifting mechanism and the chill plate 38 (S412). Then, the recycled Ni-based unidirectionally solidified superalloy component is removed from the mold 30 (S414). In the case of recycling to the melting stock, the mold heating step (S408) and the single crystal growth step (S412) can be omitted, and the solidified melting stock can be taken out (S414).
このようにすると、リサイクル対象部品の遮熱コーティングの材質が、メルティングストックまたはリサイクルＮｉ基一方向凝固超合金部品の性質に悪影響を与える場合でも、当該影響を少なくできる。このリサイクル方法では、ボンドコーティングを除く遮熱コーティングもしくはボンドコーティングを含む遮熱コーティングを剥離しても良く、また、耐酸化コーティングのみを施してあるＮｉ基一方向凝固超合金部品にそのまま、もしくは耐酸化コーティングを剥離して適用しても良く、コーティングされていないＮｉ基一方向凝固超合金部品にそのまま適用しても良い。 In this case, even when the material of the thermal barrier coating of the recycling target part adversely affects the properties of the melting stock or the recycled Ni-based unidirectionally solidified superalloy part, the influence can be reduced. In this recycling method, the thermal barrier coating excluding the bond coating or the thermal barrier coating including the bond coating may be peeled off, or the Ni-based unidirectionally solidified superalloy part having only the oxidation-resistant coating applied as it is or in an acid-resistant manner. The coating may be peeled off and applied, or it may be applied directly to an uncoated Ni-based unidirectionally solidified superalloy part.
メルティングストックへとリサイクルする場合には、Ｓ３１２やＳ４１４で出来上がったメルティングストックを貯蔵する（Ｓ３１４、Ｓ４１６）。メルティングストックよりリサイクルＮｉ基一方向凝固超合金部品を製造するには、目的とするタービン動翼やタービンベーンなどの形状に対応した鋳型を準備して、真空高周波溶解装置を用いて、再度溶湯るつぼ１０で溶解して（Ｓ３２０）、一方向凝固させて一方向凝固部品とする。 In the case of recycling to the melting stock, the melting stock produced in S312 and S414 is stored (S314, S416). To manufacture recycled Ni-based unidirectionally solidified superalloy parts from the melting stock, prepare a mold corresponding to the shape of the target turbine blade and turbine vane, etc. It is melted in the crucible 10 (S320) and solidified in one direction to obtain a one-way solidified part.
リサイクルＮｉ基一方向凝固超合金部品が、Ｎｉ基一方向凝固超合金のタービン動翼やタービンベーンなどの場合には、リサイクルＮｉ基一方向凝固超合金部品の溶体化処理を行ない（Ｓ３２２）、次に時効析出処理（Ｓ３２４）を行う。この溶体化処理と時効析出処理により、強化相（γ′相）が適切なサイズ・形状になる。続いて、必要に応じて、セラミックを含む遮熱コーティングもしくは耐酸化コーティングで被覆する（Ｓ３２６）。 When the recycled Ni-based unidirectionally solidified superalloy part is a Ni-based unidirectionally solidified superalloy turbine blade or turbine vane, etc., solution treatment of the recycled Ni-based unidirectionally solidified superalloy part is performed (S322), Next, an aging precipitation process (S324) is performed. By this solution treatment and aging precipitation treatment, the strengthening phase (γ ′ phase) becomes an appropriate size and shape. Then, if necessary, it is coated with a thermal barrier coating or an oxidation resistant coating containing ceramic (S326).
上記実施の形態においては、実施例としてＮｉ基単結晶超合金およびＮｉ基一方向凝固超合金のリサイクル方法を示したが、本発明はこれに限定されるものではなく、Ｃｏ基合金、Ｃｒ基合金、Ｆｅ基合金、Ｎｂ基合金、Ｔａ基合金、Ｗ基合金、Ｍｏ基合金、貴金属基合金、各種セラミックス等の様々な単結晶材料および一方向凝固材料にも適用できる。これは、本発明のリサイクル方法の原理は、結晶粒界を有せず不純物元素の粒界偏析を原理的に起こさない単結晶超合金では合金強度の不純物感受性が低下するという性質であり、これらの合金系やセラミックスにも同様に適用可能なためである。 In the above embodiment, the recycling method of the Ni-based single crystal superalloy and the Ni-based unidirectionally solidified superalloy has been shown as an example. However, the present invention is not limited to this, and the Co-based alloy, Cr-based alloy The present invention can also be applied to various single crystal materials and unidirectionally solidified materials such as alloys, Fe-based alloys, Nb-based alloys, Ta-based alloys, W-based alloys, Mo-based alloys, noble metal-based alloys, and various ceramics. This is because the principle of the recycling method of the present invention is that the impurity sensitivity of the alloy strength is reduced in a single crystal superalloy that does not have grain boundaries and does not cause grain boundary segregation of impurity elements in principle. This is because the present invention can also be applied to other alloy systems and ceramics.
また、上記実施の形態においては、メルティングストックへのリサイクル並びに、リサイクルＮｉ基単結晶超合金部品としてタービン動翼又はタービンベーンの場合を示したが、本発明はこれに限定されるものではなく、燃焼器ライナー、スプラッシュプレート、又はタービンディスク等の、タービン動翼やタービンベーン、又はダクトセグメント等に比較して大型な部品であっても、真空高周波溶解装置を用いて単結晶部品や一方向凝固部品とすることで、適用可能である。 Further, in the above embodiment, the recycling to the melting stock and the case of the turbine rotor blade or the turbine vane as the recycled Ni-based single crystal superalloy component are shown, but the present invention is not limited to this. Even if it is a large part compared to a turbine blade, turbine vane, or duct segment, such as a combustor liner, a splash plate, or a turbine disk, a single-crystal part or one-way Applicable by using solidified parts.
本発明のＮｉ基単結晶超合金部品のリサイクル方法によれば、初期の製造コストが普通鋳造合金や一方向凝固合金と比較して高くても、保守維持費に係るリサイクルコストが低廉であるため、Ｎｉ基単結晶超合金部品のライフタイムコストが低下し、Ｎｉ基単結晶超合金部品の普及が促進される。
また、既に製造済みのＮｉ基単結晶超合金部品が、レアメタルの損耗なくリサイクルできるので、レアメタルの供給先確保の問題が緩和されると共に、超合金を精製して合金元素を回収する場合に多量に発生する産業廃棄物処理の問題も緩和される利点がある。
さらに、本発明のＮｉ基単結晶超合金部品の直接再溶解によるリサイクル方法は、Ｎｉ基一方向凝固超合金部品、他の単結晶材料部品および他の一方向凝固材料部品にも同様に適用される。
According to the recycling method of the Ni-based single crystal superalloy part of the present invention, even if the initial manufacturing cost is higher than that of a normal casting alloy or a unidirectionally solidified alloy, the recycling cost related to maintenance and maintenance costs is low. The lifetime cost of Ni-based single crystal superalloy parts is reduced, and the spread of Ni-based single crystal superalloy parts is promoted.
In addition, since Ni-based single crystal superalloy parts that have already been manufactured can be recycled without wear and tear of rare metals, the problem of securing rare metal suppliers is alleviated, and a large amount is required when refining superalloys and recovering alloy elements. There is an advantage that the problem of the industrial waste treatment that occurs in the country is also alleviated.
Furthermore, the recycling method of the present invention based on direct remelting of Ni-based single crystal superalloy parts is similarly applied to Ni-based unidirectionally solidified superalloy parts, other single crystal material parts, and other unidirectionally solidified material parts. The
１０ 溶湯るつぼ
２０ 鋳型加熱炉
３０ 鋳型
５０ 真空容器
10 Molten crucible 20 Mold heating furnace 30 Mold 50 Vacuum container
Claims (12)
前記Ｎｉ基単結晶超合金部品のボンドコーティングを含む遮熱コーティングを剥離する工程と、
前記Ｎｉ基単結晶超合金の融点以上であって前記セラミックの融点未満の温度で、前記Ｎｉ基単結晶超合金部品を溶解する工程と、
リサイクルＮｉ基単結晶超合金部品用鋳型の温度を前記Ｎｉ基単結晶超合金の溶解温度以上に加熱する工程と、
前記リサイクルＮｉ基単結晶超合金部品用鋳型に前記溶解したＮｉ基超合金を注湯して、Ｎｉ基単結晶超合金を成長させる工程と、
前記リサイクルＮｉ基単結晶超合金部品用鋳型からリサイクルＮｉ基単結晶超合金部品を取り外す工程と、
を備えるＮｉ基単結晶超合金部品のリサイクル方法。 A Ni-based single crystal superalloy part coated with a thermal barrier coating containing a ceramic, wherein the coating layer of the thermal barrier coating is damaged or the Ni-based single crystal superalloy substrate is damaged. A recycling method for Ni-based single crystal superalloy parts,
Peeling the thermal barrier coating including the bond coating of the Ni-based single crystal superalloy component;
Melting the Ni-based single crystal superalloy component at a temperature equal to or higher than the melting point of the Ni-based single crystal superalloy and lower than the melting point of the ceramic;
Heating the temperature of the recycled Ni-based single crystal superalloy part mold to a temperature equal to or higher than the melting temperature of the Ni-based single crystal superalloy;
And pouring a Ni-base superalloy described above dissolved in the recycle Ni-based single crystal superalloy component mold, a step of growing a Ni-based single crystal superalloy,
A step of removing the recycling Ni-based single crystal superalloy component from the recycle Ni-based single crystal superalloy component mold,
A method for recycling Ni-based single crystal superalloy parts comprising:
前記耐酸化コーティングで被覆されたＮｉ基単結晶超合金部品の耐酸化コーティングを剥離する工程と、
前記Ｎｉ基単結晶超合金の融点以上で前記Ｎｉ基単結晶超合金部品を溶解する工程と、
リサイクルＮｉ基単結晶超合金部品用鋳型の温度を前記Ｎｉ基単結晶超合金の溶解温度以上に加熱する工程と、
前記リサイクルＮｉ基単結晶超合金部品用鋳型に前記溶解したＮｉ基超合金を注湯して、Ｎｉ基単結晶超合金を成長させる工程と、
前記リサイクルＮｉ基単結晶超合金部品用鋳型からリサイクルＮｉ基単結晶超合金部品を取り外す工程と、
を備えるＮｉ基単結晶超合金部品のリサイクル方法。 A Ni-based single crystal superalloy part coated with an oxidation-resistant coating , wherein the Ni-based single crystal superalloy part is damaged when the coating layer of the oxidation-resistant coating is damaged or the Ni-based single crystal superalloy substrate is damaged. A method for recycling crystalline superalloy parts,
Peeling off the oxidation resistant coating of the Ni-based single crystal superalloy part coated with the oxidation resistant coating;
Melting the Ni-based single crystal superalloy component above the melting point of the Ni-based single crystal superalloy;
Heating the temperature of the recycled Ni-based single crystal superalloy part mold to a temperature equal to or higher than the melting temperature of the Ni-based single crystal superalloy;
And pouring a Ni-base superalloy described above dissolved in the recycle Ni-based single crystal superalloy component mold, a step of growing a Ni-based single crystal superalloy,
A step of removing the recycling Ni-based single crystal superalloy component from the recycle Ni-based single crystal superalloy component mold,
A method for recycling Ni-based single crystal superalloy parts comprising:
前記Ｎｉ基一方向凝固超合金部品のボンドコーティングを含む遮熱コーティングを剥離する工程と、
前記Ｎｉ基一方向凝固超合金の融点以上であって前記セラミックの融点未満の温度で、前記Ｎｉ基一方向凝固超合金部品を溶解する工程と、
リサイクルＮｉ基一方向凝固超合金部品用鋳型の温度を前記Ｎｉ基一方向凝固超合金の溶解温度以上に加熱する工程と、
前記リサイクルＮｉ基一方向凝固超合金部品用鋳型に前記溶解したＮｉ基超合金を注湯して、Ｎｉ基一方向凝固超合金を成長させる工程と、
前記リサイクルＮｉ基一方向凝固超合金部品用鋳型からリサイクルＮｉ基一方向凝固超合金部品を取り外す工程と、
を備えるＮｉ基一方向凝固超合金部品のリサイクル方法。 A Ni-based unidirectionally solidified superalloy part coated with a thermal barrier coating containing ceramic, wherein the coating layer of the thermal barrier coating is damaged or the Ni-based unidirectionally solidified superalloy substrate is damaged A recycling method for the Ni-based unidirectionally solidified superalloy component of
Peeling the thermal barrier coating including the bond coating of the Ni-based unidirectionally solidified superalloy component;
Melting the Ni-based unidirectionally solidified superalloy component at a temperature above the melting point of the Ni-based unidirectionally solidified superalloy and below the melting point of the ceramic;
Heating the temperature of the recycled Ni-based unidirectionally solidified superalloy component mold above the melting temperature of the Ni-based unidirectionally solidified superalloy;
And pouring a Ni-base superalloy described above dissolved in the recycle Ni-base directionally solidified superalloy component mold, a step of growing a Ni-base directionally solidified superalloy,
A step of removing the recycling Ni-base directionally solidified superalloy component from the recycle Ni-base directionally solidified superalloy component mold,
A recycling method for Ni-based unidirectionally solidified superalloy parts comprising:
前記耐酸化コーティングで被覆されたＮｉ基一方向凝固超合金部品の耐酸化コーティングを剥離する工程と、
前記Ｎｉ基一方向凝固超合金の融点以上で前記Ｎｉ基一方向凝固超合金部品を溶解する工程と、
リサイクルＮｉ基一方向凝固超合金部品用鋳型の温度を前記Ｎｉ基一方向凝固超合金の溶解温度以上に加熱する工程と、
前記リサイクルＮｉ基一方向凝固超合金部品用鋳型に前記溶解したＮｉ基超合金を注湯して、Ｎｉ基一方向凝固超合金を成長させる工程と、
前記リサイクルＮｉ基一方向凝固超合金部品用鋳型からリサイクルＮｉ基一方向凝固超合金部品を取り外す工程と、
を備えるＮｉ基一方向凝固超合金部品のリサイクル方法。 A Ni-base directionally solidified superalloy component coated with oxidation resistant coating, the coated layer of oxidation resistant coating is damaged, or the Ni when damage to the Ni-base directionally solidified superalloy substrate occurs A recycling method for base unidirectionally solidified superalloy parts,
Peeling off the oxidation resistant coating of the Ni-based unidirectionally solidified superalloy part coated with the oxidation resistant coating;
Melting the Ni-based unidirectionally solidified superalloy component above the melting point of the Ni-based unidirectionally solidified superalloy;
Heating the temperature of the recycled Ni-based unidirectionally solidified superalloy component mold above the melting temperature of the Ni-based unidirectionally solidified superalloy;
And pouring a Ni-base superalloy described above dissolved in the recycle Ni-base directionally solidified superalloy component mold, a step of growing a Ni-base directionally solidified superalloy,
A step of removing the recycling Ni-base directionally solidified superalloy component from the recycle Ni-base directionally solidified superalloy component mold,
A recycling method for Ni-based unidirectionally solidified superalloy parts comprising:
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