JP3896467B2 - High temperature member excellent in nitriding resistance and method of manufacturing bright annealing furnace - Google Patents
High temperature member excellent in nitriding resistance and method of manufacturing bright annealing furnace Download PDFInfo
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Description
【０００１】
【発明の属する技術分野】
本発明は、窒化雰囲気で優れた耐久性を有する高温部材の製造方法に関するものである。また製鉄業分野で使用される鋼板用光輝焼鈍炉の窒化防止方法に関するものである。
【０００２】
【従来の技術】
１０００℃以上の高温で使用される設備機器部材は、一般に高温強度の点から高クロム高ニッケル系ステンレス鋼が使用され、大気中および還元性雰囲気であれば使用法によっては充分な耐久性が得られている。一方、窒化性雰囲気、例えば製鉄業で使用されるステンレス鋼板の光輝焼鈍炉内における水素、窒素混合ガス等の窒化性の強い雰囲気では、素材中のクロムが窒化されクロム窒化物が形成される。同窒化物は極めて脆弱なために、窒化の進行と共に脆化が進み、高温機器が冷却、加熱を受けるとその部材は熱応力により容易にクラックが発生する。
【０００３】
【発明が解決しようとする課題】
廉価な耐熱鋼を用い、その表面を耐窒化性金属で被覆することにより、廉価でかつ長寿命の高温機器用部材を得ることが本発明の課題である。高温で使用される部材には高温強度や耐酸化性の観点から主として高クロム高ニッケル合金が使用されている。しかし、雰囲気中に窒素を含有する場合には、クロム等の窒化物を形成し易い元素を多量に含む材料では、長時間の使用中に脆い窒化物が形成され、窒化物の成長により温度変動時の熱応力等に伴ってクラックが発生する。
【０００４】
この傾向は溶接接合部で特に著しい、またクラック部の補修は窒化が進行している場合は極めて困難となる。一方、近年耐窒化鋼としてニッケル基合金が使用されているが、製鉄業で使用される光輝焼鈍炉のような大規模構造物では設備費が極めて高価となる。
【０００５】
一般に製鉄業で使用される光輝焼鈍炉は、高クロム高ニッケルステンレス鋼、例えばＳＵＳ３１０Ｓ等を用いて溶接構造物として製作し、炉内は１０００℃以上の高温で使用されるが、雰囲気ガス中に窒素を含むため、炉体内面より窒化が進行し、特に溶接接合部分は窒素脆化によりクラックが発生する。またクラックの補修も窒化が進行しているため困難であった。
【０００６】
また、一般的な窒化防止には錫めっき、銅めっき、ニッケルめっき等の窒化物を生成しにくい金属をめっきする方法が行なわれているが、上記用途では雰囲気温度は１０００〜１２００℃と錫や銅の融点以上となるために前２者は使用できず、またニッケルめっきは上記大規模構造物全体を対象とした場合は高価であり、実用的ではなかった。
【０００７】
一方、めっきに代わる成膜技術の一つに溶射法があり、大規模構造物表面の被覆に適したプロセスと位置付けられている。しかしながら、溶射皮膜内部には気孔が多く、窒化物を生成しにくい金属を溶射してもその気孔を介して窒素ガスが侵入するために、窒化防止効果は不十分であった。
【０００８】
さらに、溶射法の一つとして自溶性合金を溶射し、再溶融処理を施して実質的に気孔の無い溶射皮膜を成膜する方法が知られている。また自溶性合金には耐窒化性の高いＮｉ基自溶性合金やＣｏ基自溶性合金があることも知られている。しかしながら自溶性合金の融点は１０５０℃付近にあるために、例えばステンレス鋼の光輝焼鈍炉等の高温機器の部材にこれのみを使用したのでは、１０００〜１２００℃の雰囲気温度中で溶射皮膜は溶融し脱落してしまう。
【０００９】
本発明の目的は、１０００℃以上の高温かつ窒化性の雰囲気において使用される機器等に関して、気孔無くかつ溶融脱落のない耐窒化性溶射皮膜を廉価に被覆した高温部材の製造方法を提供することである。
また、１０００℃以上の高温かつ窒化性の雰囲気で使用される光輝焼鈍炉内壁の窒化を、実質的に気孔の無い耐窒化溶射皮膜にて防止し、また同皮膜が溶融脱落なく、かつ廉価であることを特徴とする耐窒化性の優れた光輝焼鈍炉の製造方法を提供するものである。
【００１０】
【課題を解決するための手段】
本発明は、Ｎｉ基自溶性合金またはＣｏ基自溶性合金と、Ｎｉ基合金またはＣｏ基合金の窒化しにくい耐窒化耐熱合金を、交互あるいは混合して被加工物に溶射し、その後、再溶融処理を施すことにより、溶融脱落無く実質的に気孔のない溶射皮膜を成膜することを特徴とする高温部材の製造方法である。また同皮膜が炉内溶接部に形成されたことを特徴とする光輝焼鈍炉の製造方法である。
【００１１】
一般の自溶性合金の液相温度は１０４０〜１１００℃にあるため、これを超える雰囲気温度で使用すれば自溶性合金溶射皮膜は液体となり脱落する。また、同合金の固相温度は９４０〜１０００℃にあるため、気孔を除去する再溶融処理は固相温度と液相温度の間の約１００℃の間で実施される。再溶融処理により、自溶性合金溶射皮膜と母材との界面近傍では両者が含有する合金元素が相互拡散するために強い密着力が得られると共に、固相温度および液相温度共に上昇して、最終的には使用温度１０００〜１２００℃で気孔のない固相接合状態が得られる。
【００１２】
本発明は、母材上にＮｉ基自溶性合金またはＣｏ基自溶性合金と、８０％Ｎｉ基耐窒化耐熱合金を、交互または混合して被加工物に溶射し、その後再溶融処理を施すことにより、自溶性合金溶射皮膜が、耐窒化耐熱合金溶射層に拡散浸透して、実質的に気孔無く、使用温度より高い融点を有する耐窒化皮膜を提供するものである。この高温部材は母材と溶射皮膜間に強い密着力を有しかつ切欠き部となる気孔を有していないので、繰り返し熱延鋼帯応力による剥離や割れが生じないこと、および窒素含有ガスの侵入経路を遮断することは言うまでも無い。
【００１３】
また本発明は、光輝焼鈍炉の炉体内面の窒化を防止するため、母材上、特に炉体を構成する筒状母材の接合部に、Ｎｉ基自溶性合金またはＣｏ基自溶性合金を皮膜厚さが０．０３〜０．８５mmとなるように溶射した後、その上層に８０％Ｎｉ基合金の耐窒化耐熱合金を皮膜厚さが０．０３〜１．００mmとなるように溶射し、その後再溶融処理を行い、実質的に溶射被膜内の貫通気孔を含有しない溶射皮膜を形成することを特徴とする光輝焼鈍炉の製造方法である。
また本発明は、前記自溶性合金と、前記耐窒化耐熱合金を交互に溶射して多層構造とし、皮膜全体の厚さを３mm以下となるようにした後、再溶融処理を行なうことを特徴とする光輝焼鈍炉の製造方法である。
また本発明は、前記自溶性合金と前記耐窒化耐熱合金を混合した後、溶射し、その後、再溶融処理を行なうことを特徴とする光輝焼鈍炉の製造方法である。
【００１４】
【発明の実施の形態】
以下本発明の実施の形態を実施例に基づいて説明する。
図１に、試験炉内に配置する厚さ１０mmのＳＵＳ３１０ＳまたはＳＵＳ３０４製の母材（１）上に、ＪＩＳ Ｈ８３０３に規定されたＮｉ基自溶性合金ＭＳＦＮｉ４またはＣｏ基自溶性合金ＭＳＦＣｏ１（２）を溶射し、その上層に８０％Ｎｉ基合金（３）を溶射した実施例１を示す。
【００１５】
図２に、厚さ１０mmのＳＵＳ３１０Ｓ製の母材（４）上に、Ｎｉ基自溶性合金ＭＳＦＮｉ４（５）を溶射し、その上層に８０％Ｎｉ基合金（６）を溶射し、さらにその上層にＮｉ基自溶性合金ＭＳＦＮｉ４（７）を溶射し、最上層に８０％Ｎｉ基合金（８）を溶射した実施例２を示す。
【００１６】
また図３に、厚さ１０mmのＳＵＳ３１０Ｓ製またはＳＵＳ３０４製の母材（９）上に、Ｎｉ基自溶性合金ＭＳＦＮｉ４またはＣｏ基自溶性合金ＭＳＦＣｏ１と、８０％Ｎｉ基合金を、自溶性合金２に対し耐窒化合金１の比率で混合し、同混合物（１０）を溶射した実施例３を示す。
【００１７】
試験条件を表１に示す。各試験片は窒化試験前に大気中で１０５０℃で１時間の再溶融処理を行ない、気孔の無い緻密な皮膜が得られた。
次に各試験片を、流速１リットル／分の７５％Ｈ2 ＋２５％Ｎ2 ガス中に静置し、１１７０℃にて１００時間保持後に取り出して、端部からの窒素侵入の影響の無い部位の窒化物生成最大深さを測定した。窒化物生成深さは、ＥＰＭＡにより窒素およびクロムの共存相有無の確認により行なった。
【００１８】
試験結果を表２〜表４に示す。表２に見られるように、皮膜の無い面では表層から約６００μｍの深さまで窒化物が確認されたが、本発明の溶射皮膜を施した面では窒化物は全く検出されなかった。この効果は、自溶性合金皮膜上に、耐窒化耐熱合金を被覆した場合でも、自溶性合金で耐窒化耐熱合金をサンドイッチ型に被覆した皮膜でも、自溶性合金と耐窒化耐熱合金を２：１の割合で混合した後、同混合物を被覆した皮膜においても同様であった。更にこの結果は、成分の異なるＳＵＳ３１０ＳおよびＳＵＳ３０４の２種類の母材でも同様であった。
【００１９】
【表１】
【表２】
【表３】
【表４】
次に、光輝焼鈍炉に上記技術を適用した例について説明する。
請求項４の自溶性合金溶射皮膜厚さは、０．０３mm未満の場合、上層の耐窒化耐熱合金溶射皮膜の貫通気孔を埋めることができず、また、０．０３mm未満の均一な溶射皮膜の形成が実質的に困難であり、その結果密着力が低下し、皮膜の剥離が生じることから、下限を０．０３mmに限定した。また、０．８５mmを超える溶射では低融点部分が残存し、上層の耐窒化耐熱合金の溶射時の収縮応力により皮膜に膨れや上層の剥離が生じるため、上限を０．８５mmに限定した。
【００２４】
次に、上層の耐窒化耐熱合金溶射皮膜の厚さは、０．０３mm未満では、下層自溶性合金の溶融点を、耐窒化性を損なうことなく光輝焼鈍炉炉内雰囲気温度以上に上げることは困難なことから、下限を０．０３mmに限定した。また、１．００mmを超える溶射では、皮膜前面に自溶性合金が拡散浸透せず、上層皮膜表面付近に気孔が残るため、上限を１．００mmとした。
【００２５】
次に、請求項５に関して説明する。
請求項５は、請求項４を繰り返し交互に行なうことにより、厚さを増し、耐久性を向上させるためのものである。ただし、皮膜全体の厚さが３mmを超える溶射を施した場合は、溶射時の圧縮残留応力が大きく、再溶融時に皮膜の膨れ、剥離が発生するため、上限を３mmに限定した。
【００２６】
次に、請求項６に関して説明する。
請求項６は、請求項４の自溶性合金、および耐窒化耐熱合金を混合して請求項５と同様の効果が得られる様に発明したものであり、自溶性合金と耐窒化耐熱合金を混合し、同混合物を単独の溶射機を用いて溶射しても、複数の溶射機を使用して溶射中に自溶性合金、耐窒化耐熱合金を混合して溶射層を形成してもよい。
【００２７】
次に、光輝焼鈍炉炉体内面溶接部に本発明を適用した実施例４を示す。
従来、光輝焼鈍炉炉体にＳＵＳ３１０Ｓを使用した場合、炉体内面溶接部に窒化による亀裂がＸ線検査で認められていた。
実施例４では、ＳＵＳ３１０Ｓの炉体上に、Ｎｉ基自溶性合金ＭＳＦＮｉ４を０．０５mmの厚さにガスプラズマ溶射を行なった後、その上層に８０％Ｎｉ基合金を０．１mmの厚さにガスプラズマ溶射し、さらに最上層にＮｉ基自溶性合金ＭＳＦＮｉ４を０．０５mmの厚さに溶射した後、１０５０℃で１時間の再溶融処理を行なった。
３層構造の本発明皮膜を、光輝焼鈍炉内壁溶接線部に適用した結果、Ｘ線検査でも亀裂が全く認められず、窒化防止性能の確認ができた。
【００２８】
【発明の効果】
本発明によれば、窒素を含有する１０００℃以上のガス中で使用される材料に関して、耐窒素脆化特性に優れた部材の提供が可能となる。
また、光輝焼鈍炉の炉体内面の窒化を防止することにより、接合部のクラック発生を防止し、設備停止時間の短縮、設備補修費用の大幅削減が可能な光輝焼鈍炉を得ることができる。
【図面の簡単な説明】
【図１】窒化試験炉内配置の概略と耐窒化性高温部材表面皮膜を示す図。
【図２】窒化試験炉内配置の概略と耐窒化性高温部材表面皮膜を示す図。
【図３】窒化試験炉内配置の概略と耐窒化性高温部材表面皮膜を示す図。
【符号の説明】
１：ＳＵＳ３１０ＳまたはＳＵＳＳ３０４製の母材
２：Ｎｉ基自溶性合金ＭＳＦＮｉ４またはＣｏ基自溶性合金ＭＳＦＣｏ１の被覆層
３：８０％Ｎｉ基合金の被覆層
４：ＳＵＳ３１０Ｓ製の母材
５：Ｎｉ基自溶性合金ＭＳＦＮｉ４の被覆層
６：８０％Ｎｉ基合金被覆層
７：Ｎｉ基自溶性合金ＭＳＦＮｉ４被覆層
８：８０％Ｎｉ基合金被覆層
９：ＳＵＳ３１０Ｓ製の母材
１０：Ｎｉ基自溶性合金ＭＳＦＮｉ４またはＣｏ基自溶性合金ＭＳＦＣｏ１と、８０％
Ｎｉ基合金を、自溶性合金２に対し耐窒化合金１の比率で混合した被覆層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a high-temperature member having excellent durability in a nitriding atmosphere. Moreover, it is related with the nitriding prevention method of the bright annealing furnace for steel plates used in the steel industry field.
[0002]
[Prior art]
Equipment parts used at high temperatures of 1000 ° C or higher are generally made of high-chromium high-nickel stainless steel from the viewpoint of high-temperature strength. Sufficient durability can be obtained depending on the method of use in the atmosphere and in a reducing atmosphere. It has been. On the other hand, in a nitriding atmosphere, for example, in a bright annealing furnace of a stainless steel plate used in the steel industry, such as hydrogen and nitrogen mixed gas, a strong nitriding atmosphere such as chromium is nitrided to form chromium nitride. Since the nitride is extremely brittle, embrittlement progresses with the progress of nitriding, and when a high-temperature device is cooled and heated, the member easily cracks due to thermal stress.
[0003]
[Problems to be solved by the invention]
It is an object of the present invention to obtain an inexpensive and long-life member for high-temperature equipment by using inexpensive heat-resistant steel and coating the surface with a nitriding metal. High chromium and nickel alloys are mainly used for members used at high temperatures from the viewpoint of high temperature strength and oxidation resistance. However, when nitrogen is contained in the atmosphere, a material containing a large amount of elements that easily form nitrides such as chromium forms brittle nitrides during long-term use, and temperature fluctuations occur due to nitride growth. Cracks occur along with the thermal stress at the time.
[0004]
This tendency is particularly remarkable at the welded joint, and repair of the crack is extremely difficult when nitriding is in progress. On the other hand, nickel-based alloys have been used in recent years as nitriding-resistant steel, but equipment costs are extremely high in large-scale structures such as bright annealing furnaces used in the steel industry.
[0005]
A bright annealing furnace generally used in the steel industry is manufactured as a welded structure using high chromium high nickel stainless steel, such as SUS310S, and the furnace is used at a high temperature of 1000 ° C. or higher. Since nitrogen is contained, nitriding proceeds from the inner surface of the furnace body, and cracks are generated particularly in the welded joint due to nitrogen embrittlement. Repair of cracks was also difficult because nitriding had progressed.
[0006]
In addition, for general nitriding prevention, tin plating, copper plating, nickel plating, and other methods of plating a metal that does not easily generate nitrides are performed. In the above application, the atmospheric temperature is 1000 to 1200 ° C. Since the melting point of copper is higher than the melting point, the former two cannot be used, and nickel plating is expensive and impractical when the entire large-scale structure is used.
[0007]
On the other hand, a thermal spraying method is one of film forming techniques that replaces plating, and is positioned as a process suitable for coating the surface of a large-scale structure. However, there are many pores inside the sprayed coating, and even if a metal that does not easily form nitrides is sprayed, nitrogen gas penetrates through the pores, so that the nitriding prevention effect is insufficient.
[0008]
Furthermore, as one of the thermal spraying methods, a method is known in which a self-fluxing alloy is sprayed and remelted to form a sprayed coating substantially free of pores. It is also known that self-fluxing alloys include Ni-based self-fluxing alloys and Co-based self-fluxing alloys with high nitriding resistance. However, since the melting point of the self-fluxing alloy is in the vicinity of 1050 ° C., for example, if only this is used as a member of a high-temperature apparatus such as a bright annealing furnace made of stainless steel, the sprayed coating melts in an atmospheric temperature of 1000 to 1200 ° C. It will fall off.
[0009]
An object of the present invention is to provide a method for producing a high-temperature member that is inexpensively coated with a nitriding-resistant sprayed coating that does not have pores and does not melt and drop off, for equipment used in a high-temperature and nitriding atmosphere of 1000 ° C. or higher. It is.
In addition, the nitriding of the inner wall of the bright annealing furnace used in a high temperature and nitriding atmosphere of 1000 ° C. or higher is prevented by a nitriding-resistant sprayed coating that is substantially free of pores, and the coating does not melt and fall off and is inexpensive. The present invention provides a method for manufacturing a bright annealing furnace having excellent nitriding resistance.
[0010]
[Means for Solving the Problems]
In the present invention, a Ni-based self-fluxing alloy or a Co-based self-fluxing alloy and a Ni-based alloy or a Co-based alloy, a nitriding resistant heat-resistant alloy that is difficult to nitride, are alternately or mixed and sprayed onto the workpiece, and then remelted. A process for producing a high-temperature member, characterized in that a thermal spray coating substantially free of pores without melting and falling off is formed by performing treatment. Moreover, it is the manufacturing method of the bright annealing furnace characterized by the same film | membrane being formed in the in-furnace welding part.
[0011]
Since the liquid phase temperature of a general self-fluxing alloy is 1040 to 1100 ° C., the self-fluxing alloy sprayed coating becomes a liquid and falls off when used at an ambient temperature exceeding this. Further, since the solid phase temperature of the alloy is 940 to 1000 ° C., the remelting process for removing pores is performed between about 100 ° C. between the solid phase temperature and the liquid phase temperature. Due to the remelting treatment, strong adhesion is obtained because the alloy elements contained in both of them are diffused in the vicinity of the interface between the self-fluxing alloy spray coating and the base material, and both the solid phase temperature and the liquid phase temperature are increased. Ultimately, a solid phase bonded state without pores is obtained at a use temperature of 1000 to 1200 ° C.
[0012]
The present invention includes a Ni-based self-fluxing alloy or Co-based self-fluxing alloy on the base material, a 80% Ni-base耐窒of heat alloy, alternating or mixed and sprayed onto the workpiece is subjected to subsequent remelting process Accordingly, the self-fluxing alloy sprayed coating diffuses and penetrates into the nitrided heat resistant alloy sprayed layer, and provides a nitrided resistant coating having substantially no pores and a melting point higher than the use temperature. Since this high-temperature member has strong adhesion between the base material and the thermal spray coating and does not have pores that become notches, it does not repeatedly peel and crack due to hot-rolled steel strip stress, and nitrogen-containing gas It goes without saying that the intrusion route is blocked.
[0013]
Further, the present invention provides a Ni-based self-fluxing alloy or a Co-based self-fluxing alloy on the base material, particularly at the joint of the cylindrical base material constituting the furnace body, in order to prevent nitriding of the inner surface of the bright annealing furnace. after coating thickness was sprayed so that 0.03～0.85Mm, spraying 80% Ni-based alloy gold耐窒of heat-resistant alloy of the upper layer thereof as film thickness becomes 0.03~1.00mm Then, a remelting process is performed to form a thermal spray coating substantially free of through-holes in the thermal spray coating, and a method for manufacturing a bright annealing furnace.
Further, the present invention is characterized in that the self-fluxing alloy and the nitriding heat-resistant alloy are sprayed alternately to form a multilayer structure, and the total thickness of the coating is 3 mm or less, and then remelting treatment is performed. This is a method of manufacturing a bright annealing furnace.
The present invention is also a method for producing a bright annealing furnace characterized in that the self-fluxing alloy and the nitriding heat-resistant alloy are mixed, sprayed, and then remelted.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples.
FIG. 1 shows a Ni-based self-fluxing alloy MSFNi4 or a Co-based self-fluxing alloy MSFCo1 (2) defined in JIS H8303 on a 10 mm-thick SUS310S or SUS304 base material (1) placed in a test furnace. sprayed, showing a first embodiment of the spraying 80% Ni-based alloy is gold (3) thereon.
[0015]
In FIG. 2, a Ni-based self-fluxing alloy MSFNi4 (5) is sprayed on a 10 mm-thick SUS310S base material (4), and an 80% Ni-based alloy (6) is sprayed on the upper layer. Example 2 in which Ni-based self-fluxing alloy MSFNi4 (7) was sprayed and 80% Ni-based alloy (8) was sprayed on the uppermost layer is shown.
[0016]
Also in Figure 3, on SUS310S steel or SUS304-made base material having a thickness of 10 mm (9), and Ni-based self-fluxing alloy MSFNi4 or Co-based self-fluxing alloy MSFCo1, a 80% Ni-based alloy metal, self-fluxing alloy 2 Example 3 in which the mixture was mixed at a ratio of the nitriding resistant alloy 1 and the mixture (10) was sprayed is shown.
[0017]
Table 1 shows the test conditions. Each test piece was remelted at 1050 ° C. for 1 hour in the air before the nitriding test, and a dense film without pores was obtained.
Next, each test piece was allowed to stand in 75% H 2 + 25% N 2 gas at a flow rate of 1 liter / min, and taken out after being held at 1170 ° C. for 100 hours, and was not affected by nitrogen intrusion from the end. The maximum depth of nitride formation was measured. The nitride formation depth was determined by confirming the presence or absence of a coexisting phase of nitrogen and chromium by EPMA.
[0018]
The test results are shown in Tables 2 to 4. As can be seen from Table 2, nitride was confirmed from the surface layer to a depth of about 600 μm on the surface without the coating, but no nitride was detected on the surface on which the thermal spray coating of the present invention was applied. This effect is obtained when the self-fluxing alloy film and the nitriding heat-resistant alloy are coated with a nitriding heat-resistant alloy or a nitriding heat-resistant alloy with a self-fluxing alloy in a sandwich type. The same applies to the film coated with the mixture after mixing at the ratio of. Furthermore, this result was the same for two types of base materials of SUS310S and SUS304 having different components.
[0019]
[Table 1]
[Table 2]
[Table 3]
[Table 4]
Next, an example in which the above technique is applied to a bright annealing furnace will be described.
If the thickness of the self-fluxing alloy sprayed coating of claim 4 is less than 0.03 mm, the through-holes of the upper nitriding heat resistant alloy sprayed coating cannot be filled, and a uniform sprayed coating of less than 0.03 mm The lower limit was limited to 0.03 mm because formation was substantially difficult, resulting in reduced adhesion and peeling of the film. Further, when the thermal spraying exceeds 0.85 mm, the low melting point portion remains and the upper layer is limited to 0.85 mm because the upper layer is swelled or peeled off due to shrinkage stress during thermal spraying of the nitriding heat resistant alloy.
[0024]
Next, if the thickness of the upper layer nitridation resistant heat resistant alloy sprayed coating is less than 0.03 mm, the melting point of the lower layer self-fluxing alloy can be raised above the ambient temperature in the bright annealing furnace without impairing nitriding resistance. Due to difficulties, the lower limit was limited to 0.03 mm. Further, in the thermal spraying exceeding 1.00 mm, the self-fluxing alloy does not diffuse and penetrate on the front surface of the coating, and pores remain in the vicinity of the upper coating surface, so the upper limit was set to 1.00 mm.
[0025]
Next, claim 5 will be described.
A fifth aspect of the present invention is to increase the thickness and improve the durability by repeatedly performing the fourth aspect alternately. However, when the thermal spraying of the entire coating exceeds 3 mm, the compressive residual stress at the time of thermal spraying is large, and the swelling and peeling of the coating occur at the time of remelting, so the upper limit was limited to 3 mm.
[0026]
Next, claim 6 will be described.
Claim 6 is an invention in which the self-fluxing alloy of claim 4 and the nitriding heat-resistant alloy are mixed to obtain the same effect as that of claim 5, and the self-fluxing alloy and the nitriding heat-resistant alloy are mixed. The thermal spray layer may be formed by spraying the mixture using a single thermal sprayer or by mixing a self-fluxing alloy and a nitriding heat-resistant alloy during thermal spraying using a plurality of thermal sprayers.
[0027]
Next, Example 4 in which the present invention is applied to a bright annealing furnace furnace body inner surface welding portion will be described.
Conventionally, when SUS310S was used for a bright annealing furnace furnace body, cracks due to nitriding were observed in the furnace body inner surface welded part by X-ray inspection.
In Example 4, a Ni-based self-fluxing alloy MSFNi4 was subjected to gas plasma spraying to a thickness of 0.05 mm on a SUS310S furnace body, and then an 80% Ni-based alloy was formed to a thickness of 0.1 mm on the upper layer. Gas plasma spraying was performed, and Ni-based self-fluxing alloy MSFNi4 was sprayed to a thickness of 0.05 mm on the uppermost layer, and then remelting treatment was performed at 1050 ° C. for 1 hour.
As a result of applying the film of the present invention having a three-layer structure to the bright annealing furnace inner wall weld line, no cracks were observed even in the X-ray inspection, and the anti-nitriding performance could be confirmed.
[0028]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, regarding the material used in the 1000 degreeC or more gas containing nitrogen, it becomes possible to provide the member excellent in the nitrogen embrittlement resistance.
Further, by preventing nitriding of the inner surface of the bright annealing furnace body, it is possible to obtain a bright annealing furnace capable of preventing the occurrence of cracks in the joints, shortening the equipment stop time and greatly reducing the equipment repair cost.
[Brief description of the drawings]
FIG. 1 is a diagram showing an outline of the arrangement in a nitriding test furnace and a surface film of a nitriding resistant high temperature member.
FIG. 2 is a diagram showing an outline of arrangement in a nitriding test furnace and a surface film of a nitriding resistant high temperature member.
FIG. 3 is a diagram showing an outline of arrangement in a nitriding test furnace and a surface film of a nitriding resistant high temperature member.
[Explanation of symbols]
1: SUS310S or SUSS304 made of a base material 2: Ni-based self-fluxing alloy MSFNi4 or Co-based self-fluxing alloy MSFCo1 the coating layer 3: 80% Ni-based alloy coating layer of gold 4: SUS310S steel base material 5: Ni-based self Coating layer of soluble alloy MSFNi4 6: 80% Ni-based alloy coating layer 7: Ni-based self-fluxing alloy MSFNi4 coating layer 8: 80% Ni-based alloy coating layer 9: Base material made of SUS310S 10: Ni-based self-fluxing alloy MSFNi4 or Co-based self-fluxing alloy MSFCo1 and 80%
The Ni-based alloy gold were to self-fluxing alloy 2 were mixed in a ratio of耐窒alloying first covering layer
Claims (6)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21286996A JP3896467B2 (en) | 1996-08-12 | 1996-08-12 | High temperature member excellent in nitriding resistance and method of manufacturing bright annealing furnace |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP21286996A JP3896467B2 (en) | 1996-08-12 | 1996-08-12 | High temperature member excellent in nitriding resistance and method of manufacturing bright annealing furnace |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH1053880A JPH1053880A (en) | 1998-02-24 |
| JP3896467B2 true JP3896467B2 (en) | 2007-03-22 |
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| JP21286996A Expired - Fee Related JP3896467B2 (en) | 1996-08-12 | 1996-08-12 | High temperature member excellent in nitriding resistance and method of manufacturing bright annealing furnace |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2002088461A (en) * | 2000-09-14 | 2002-03-27 | Kawasaki Steel Corp | Corrosion resisting roll |
| KR100474414B1 (en) * | 2001-11-27 | 2005-03-08 | 조우석 | Bright heat treatment method of inert neutral-gas environment at a high temperature |
| JP4565434B2 (en) * | 2004-03-23 | 2010-10-20 | 地方独立行政法人北海道立総合研究機構 | Self-fluxing alloy sprayed parts that do not peel |
| JP4546867B2 (en) * | 2005-04-05 | 2010-09-22 | 新日本製鐵株式会社 | Water-cooled steel pipe structure with excellent corrosion resistance and wear resistance and its manufacturing method |
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| JPH1053880A (en) | 1998-02-24 |
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