JPH07228955A - Production of cast fe-cr-ni alloy, excellent in strength at high temperature and product using the same - Google Patents
Production of cast fe-cr-ni alloy, excellent in strength at high temperature and product using the sameInfo
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- JPH07228955A JPH07228955A JP4513394A JP4513394A JPH07228955A JP H07228955 A JPH07228955 A JP H07228955A JP 4513394 A JP4513394 A JP 4513394A JP 4513394 A JP4513394 A JP 4513394A JP H07228955 A JPH07228955 A JP H07228955A
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Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、プレスによる恒温鍛
造や超塑性成形などのように、成形用金型を素材の温度
まで加熱して使用する金型用材料に好適な、高温強度に
優れる鋳造Ｆｅ−Ｃｒ−Ｎｉ合金およびそれを用いた製
品の製造方法に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is excellent in high-temperature strength, which is suitable for mold materials such as isothermal forging by pressing and superplastic forming, which are used by heating the mold to the temperature of the material. The present invention relates to a cast Fe-Cr-Ni alloy and a method of manufacturing a product using the same.
【０００２】[0002]
【従来の技術】近年、２相ステンレス鋼やＴｉ−６％Ａ
ｌ−４％Ｖの組成を有するチタン合金板などのように、
熱間で超塑性を示す素材が開発されつつある。そして、
そのような素材によれば、気体の圧力を利用して超塑性
板材を変形させる超塑性成形が可能となった。この超塑
性成形は、素材が金型との接触により冷却されて超塑性
の性質が損なわれないようにするために、金型を素材と
同等の温度まで加熱して行われる。2. Description of the Related Art Recently, duplex stainless steel and Ti-6% A
Like a titanium alloy plate having a composition of 1-4% V,
Materials that are hot and superplastic are being developed. And
With such a material, superplastic forming capable of deforming the superplastic plate material using the pressure of gas has become possible. This superplastic forming is performed by heating the mold to a temperature equivalent to that of the material so that the material is not cooled by contact with the mold and the superplastic property is not impaired.
【０００３】超塑性成形用の金型材料としては、高温強
度に優れたＳＫＤ材やＳＫＨ材が適しているが、それら
は高価であり、しかも、そのような高価な材料に型彫面
を機械加工で形成し、さらに熱処理を行うのでは金型が
極めて割高となる。このため、従来より超塑性成形ある
いは恒温鍛造のための金型を鋳造で成形する方法が開発
され、そのための金型用材料として合金鋳鋼のＨＫ−２
０材（０．２Ｃ−２０Ｎｉ−２５Ｃｒ）や高合金鋳鋼の
ＨＰ−４０材などが使用されつつある。As a die material for superplastic forming, SKD material and SKH material which are excellent in high temperature strength are suitable, but they are expensive, and moreover, a die surface is machined on such an expensive material. If it is formed by processing and then heat-treated, the mold becomes extremely expensive. Therefore, conventionally, a method of forming a die for superplastic forming or isothermal forging by casting has been developed, and as a die material therefor, HK-2 alloy cast steel is used.
0 material (0.2C-20Ni-25Cr) and HP-40 material of high alloy cast steel are being used.
【０００４】[0004]
【発明が解決しようとする課題】しかしながら、ＨＫ−
２０材を超塑性成形用あるいは恒温鍛造用の金型として
高温で用いた場合、金型の高温強度が充分でないため、
成形の際に金型が変形したり磨耗したりし易く、寿命が
短いという欠点があった。一方、ＨＰ−４０材は、ＨＫ
−２０材よりも高温強度に優れているものの、金型を鋳
造する際の鋳込後の冷却過程で、金型のコーナー部や凹
部に割れが生じ易く、殆ど製造が不可能であることが判
明した。However, HK-
When 20 materials are used at a high temperature as a mold for superplastic forming or isothermal forging, the high temperature strength of the mold is not sufficient.
There is a defect that the mold is easily deformed or worn during molding, and the life is short. On the other hand, HP-40 material is HK
Although it is superior to -20 material in high temperature strength, cracks are likely to occur in the corners and recesses of the mold during the cooling process after casting when the mold is cast, which makes it almost impossible to manufacture. found.
【０００５】[0005]
【発明の目的】この発明は、例えば超塑性成形用金型と
して用いたときに、素材と同等の温度に加熱されても高
い強度を維持することができるとともに、鋳造時の冷却
過程における製品への割れの発生を防止することができ
る鋳造Ｆｅ−Ｃｒ−Ｎｉ合金およびそれを用いた製品の
製造方法を提供することを目的としている。It is an object of the present invention, when used as a superplastic forming die, for example, to maintain high strength even when heated to a temperature equivalent to that of the raw material, and to provide a product in a cooling process during casting. It is an object of the present invention to provide a cast Fe-Cr-Ni alloy capable of preventing the occurrence of cracks in steel and a method for producing a product using the same.
【０００６】本発明者らは、鋳造Ｆｅ−Ｃｒ−Ｎｉ合金
の高温での強度を向上させるには、オーステナイト素地
を強化することが先決条件であるとの観点から種々の実
験を重ねたところ、そのような元素としてはＷが最も有
効であり、Ｗを０．３〜３ｗｔ％（以下、「％」と略称
する）含有させることにより所望の高温強度が得られる
ことを見いだした。この発明は、上記実験結果に基づい
てなされたものであり、下記の成分組成を有することを
特徴としている。The present inventors have conducted various experiments from the viewpoint that strengthening the austenite matrix is a prerequisite for improving the strength of the cast Fe-Cr-Ni alloy at high temperatures. It has been found that W is the most effective as such an element, and the desired high temperature strength can be obtained by including W in an amount of 0.3 to 3 wt% (hereinafter abbreviated as “%”). The present invention was made based on the above experimental results, and is characterized by having the following component composition.
【０００７】すなわち、本発明は、Ｃ：０．０５〜１．
０ｗｔ％，Ｓｉ：≦１．５ｗｔ％，Ｍｎ：≦１．５ｗｔ
％，Ｐ：≦０．０３％，Ｓ：≦０．００５ｗｔ％，Ｎ
ｉ：２０〜４０ｗｔ％，Ｃｒ：２０〜４０ｗｔ％，Ｗ：
０．３〜３．０ｗｔ％，Ａｌ：０．００１〜０．０４ｗ
ｔ％，Ｃａ：０．００１〜０．０１ｗｔ％，Ｎ：０．０
１〜０．２ｗｔ％を含有し、残部は実質的にＦｅからな
ることを特徴とする高温強度に優れる鋳造Ｆｅ−Ｃｒ−
Ｎｉ合金である。That is, according to the present invention, C: 0.05-1.
0 wt%, Si: ≦ 1.5 wt%, Mn: ≦ 1.5 wt
%, P: ≤ 0.03%, S: ≤ 0.005 wt%, N
i: 20-40 wt%, Cr: 20-40 wt%, W:
0.3-3.0 wt%, Al: 0.001-0.04w
t%, Ca: 0.001 to 0.01 wt%, N: 0.0
1% to 0.2% by weight, the balance being substantially Fe, characterized by high temperature strength cast Fe-Cr-
It is a Ni alloy.
【０００８】そして、この合金素材を鋳込み、その後８
００〜１０００゜Ｃの温度範囲まで徐冷した後に、上記
温度範囲で１０時間以上の熱処理を行うことにより、コ
ーナー部や凹部に割れが生じない目的の製品を得ること
ができる。Then, this alloy material is cast, and then 8
After gradually cooling to a temperature range of 00 to 1000 ° C., heat treatment is performed for 10 hours or more within the above temperature range to obtain a target product in which cracks do not occur in the corners or recesses.
【０００９】[0009]
【作用】次に、この発明の鋳造Ｆｅ−Ｃｒ−Ｎｉ合金に
おける成分組成について、その作用とともに限定の理由
を詳細に説明する。Next, the composition of the cast Fe-Cr-Ni alloy of the present invention will be described in detail together with its function and the reason for limitation.
【００１０】Ｃ：Ｃは合金の高温強度を向上させる元素
であり、必要な高温強度を得るためには０．０５％以上
添加する必要がある。一方、１．０％を越えると有害な
粗大１次Ｃｒ炭化物が析出し、合金の脆化の原因とな
る。よって、Ｃの含有量は０．０５〜１．０％とした。
好ましくは０．２〜０．５％の範囲が良い。C: C is an element that improves the high temperature strength of the alloy and must be added in an amount of 0.05% or more to obtain the required high temperature strength. On the other hand, if it exceeds 1.0%, harmful coarse primary Cr carbide is precipitated, which causes embrittlement of the alloy. Therefore, the content of C is set to 0.05 to 1.0%.
The range of 0.2 to 0.5% is preferable.
【００１１】Ｓｉ：Ｓｉは鋳造時の湯流性を向上させる
ので、凹凸の起伏の激しい製品を鋳造するための合金に
は重要な成分である。さらに、Ｓｉは製品の耐酸化性を
改善するので、高温で使用する製品の合金成分として有
効である。しかしながら、１．５％を超えて含有すると
靱性および高温強度が低下するので、Ｓｉの含有量は
１．５％以下とした。好ましくは１．１％以下、より好
ましくは０．９５％以下が良い。Si: Si improves the flowability at the time of casting and is therefore an important component in an alloy for casting a product in which unevenness is rugged. Furthermore, Si improves the oxidation resistance of the product, and is therefore effective as an alloying component for products used at high temperatures. However, if the content exceeds 1.5%, the toughness and the high temperature strength decrease, so the Si content was set to 1.5% or less. It is preferably 1.1% or less, more preferably 0.95% or less.
【００１２】Ｍｎ：Ｍｎは脱酸剤として有効な元素であ
るが、１．５％を超えて含有すると高温強度が低下す
る。よって、Ｍｎの含有量は１．５％以下とした。好ま
しくは１．２％以下、より好ましくは１．０％以下が良
い。Mn: Mn is an element effective as a deoxidizing agent, but if it is contained in an amount exceeding 1.5%, the high temperature strength will decrease. Therefore, the Mn content is set to 1.5% or less. It is preferably 1.2% or less, more preferably 1.0% or less.
【００１３】Ｐ：Ｐは不純物として含まれる元素であ
り、０．０３％を越えると溶接性に悪影響を与える。よ
って、Ｐの含有量は０．０３％以下とした。P: P is an element contained as an impurity, and if it exceeds 0.03%, the weldability is adversely affected. Therefore, the content of P is set to 0.03% or less.
【００１４】Ｓ：Ｓは不純物として含まれる元素であ
り、０．００５％を越えると溶接性に悪影響を与える。
よって、Ｓの含有量は０．００５％以下とした。S: S is an element contained as an impurity, and if it exceeds 0.005%, the weldability is adversely affected.
Therefore, the content of S is set to 0.005% or less.
【００１５】Ｎｉ：Ｎｉは素地のオーステナイトを安定
化するとともに、高温強度、耐高温腐食性を向上させる
元素である。合金の組織を安定にし、必要な高温強度を
得るには２０％以上含有する必要がある。一方、４０％
を越えても高温強度の増加はさほど顕著ではない。よっ
て、Ｎｉの含有量は２０〜４０％とした。好ましくは３
０〜３６％の範囲が良い。Ni: Ni is an element that stabilizes the austenite of the base material and improves the high temperature strength and high temperature corrosion resistance. In order to stabilize the structure of the alloy and obtain the required high temperature strength, it is necessary to contain 20% or more. On the other hand, 40%
Even if it exceeds, the increase in high temperature strength is not so remarkable. Therefore, the content of Ni is set to 20 to 40%. Preferably 3
The range of 0 to 36% is preferable.
【００１６】Ｃｒ：Ｃｒは合金の耐酸化性、耐高温腐食
性を向上させる元素である。必要な耐酸化性、耐高温腐
食性を得るには２０％以上含有する必要がある。一方、
４０％を越えると炭化物の過剰な析出により脆化が現れ
る。よって、Ｃｒの含有量は２０〜４０％とした。好ま
しくは２４〜２７％の範囲が良い。Cr: Cr is an element that improves the oxidation resistance and high temperature corrosion resistance of the alloy. To obtain the required oxidation resistance and high temperature corrosion resistance, it is necessary to contain 20% or more. on the other hand,
If it exceeds 40%, embrittlement appears due to excessive precipitation of carbides. Therefore, the content of Cr is set to 20 to 40%. The range of 24 to 27% is preferable.
【００１７】Ｗ：Ｗはこの発明の鋳造Ｆｅ−Ｃｒ−Ｎｉ
合金の特徴、特に高温強度を付与する重要な元素であっ
て、オーステナイト素地に固溶して高温強度を向上させ
る。必要な高温強度を得るには０．３％以上添加する必
要がある。一方、３％を越えると炭化物として析出する
ため、高温強度の増加はさほど顕著ではなくなる。よっ
て、Ｗの含有量は０．３〜３％とした。好ましくは０．
５〜３．０％の範囲、より好ましくは１．０〜３．０％
の範囲が良い。W: W is the cast Fe-Cr-Ni of this invention
It is an important element that gives the characteristics of the alloy, especially high temperature strength, and improves the high temperature strength by forming a solid solution in the austenite matrix. To obtain the required high temperature strength, it is necessary to add 0.3% or more. On the other hand, if it exceeds 3%, the precipitation at high temperature is precipitated, so that the increase in high temperature strength is not so remarkable. Therefore, the W content is set to 0.3 to 3%. Preferably 0.
5 to 3.0% range, more preferably 1.0 to 3.0%
The range is good.
【００１８】Ａｌ：Ａｌは靱性の向上に効果があり、ま
た、鋼の精錬時に脱酸剤として用いる必要からあまりに
低く抑えることは適当でないので、０．００１％以上と
する。しかしながら、Ａｌを過剰に含有すると粗大なＡ
ｌ2Ｏ3が素地中に存在して合金の靱性を劣化させる。合
金の靱性が劣化すると、恒温鍛造用金型として使用した
ときに割れが発生し易くなるばかりでなく、鋳造時の冷
却過程において熱応力により素地に亀裂が発生し易くな
る。本発明者らの実験によれば、Ａｌの含有量が０．０
４％を超えると、後述する本発明の熱処理を行っても製
品に割れが発生することが確認された。よって、Ａｌ含
有量は０．００１〜０．０４％とした。Al: Al has the effect of improving toughness, and since it is necessary to use it as a deoxidizer at the time of refining steel, it is not appropriate to keep it too low, so the content is made 0.001% or more. However, if Al is contained excessively, coarse A
l 2 O 3 is present in the matrix and deteriorates the toughness of the alloy. If the toughness of the alloy deteriorates, not only cracks are likely to occur when used as a mold for constant temperature forging, but also cracks are likely to occur in the substrate due to thermal stress during the cooling process during casting. According to the experiments by the present inventors, the content of Al is 0.0
It has been confirmed that when the content exceeds 4%, cracks occur in the product even when the heat treatment of the present invention described later is performed. Therefore, the Al content is set to 0.001 to 0.04%.
【００１９】Ｃａ：Ｃａも靱性の向上に効果があり、ま
た、鋼の精錬時に脱酸剤として用いるので０．００１％
以上は必要である。しかしながら、Ｃａを過剰に含有す
ると素地中に粗大なＣａＳが多量に存在して合金の靱性
を劣化させる。この場合も上記Ａｌと同様に、鋳造時の
冷却過程において熱応力により素地に亀裂が発生し易く
なる。本発明者らの実験によれば、Ｃａの含有量が０．
０１％を超えると、後述する本発明の熱処理を行っても
製品に割れが発生することが確認された。よって、Ｃａ
の含有量は０．００１〜０．０１％とした。Ca: Ca is also effective in improving the toughness, and since it is used as a deoxidizer during the refining of steel, it is 0.001%.
The above is necessary. However, if Ca is contained in excess, a large amount of coarse CaS is present in the base material, which deteriorates the toughness of the alloy. In this case as well, similar to Al, cracks are likely to occur in the substrate due to thermal stress during the cooling process during casting. According to the experiments by the present inventors, the content of Ca is 0.
It has been confirmed that when the content exceeds 01%, cracks occur in the product even when the heat treatment of the present invention described below is performed. Therefore, Ca
Content of 0.001 to 0.01%.
【００２０】Ｎ：Ｎは合金の高温強度を向上させる元素
であるが、所望の高温強度を得るためには０．０１％以
上含有させる必要がある。一方、０．２％を越えると炭
窒化物の析出が著しくなって靱性を劣化させる。よっ
て、Ｎの含有量は０．０１〜０．２％の範囲とした。N: N is an element that improves the high temperature strength of the alloy, but it is necessary to contain 0.01% or more to obtain the desired high temperature strength. On the other hand, if it exceeds 0.2%, the precipitation of carbonitrides becomes remarkable and the toughness deteriorates. Therefore, the content of N is set to the range of 0.01 to 0.2%.
【００２１】次に、本発明合金の製造方法、特に熱処理
の条件を中心に説明する。上記成分組成よりなる合金素
材を鋳造する場合には、製品のコーナー部や凹部での割
れの発生を防止するための熱処理が必要である。それは
次のような理由による。すなわち、鋳込み後徐冷するだ
けで熱処理を行わない従来の製造方法では、凝固時に晶
出する１次Ｃｒ炭化物が矩形状を呈し、かつ、その周辺
がＣｒ欠乏域となっていることが本発明者らにより発見
された。そのような矩形状の１次Ｃｒ炭化物は、冷却時
に生じる熱応力によって亀裂が生じ易く、また、Ｃｒ欠
乏相と素地との境界にも亀裂が生じ易い。このように、
従来の製造方法において製品のコーナー部や凹部で割れ
が生じていた原因は、矩形状の１次Ｃｒ炭化物とその周
辺のＣｒ欠乏域であることが判明した。よって、製品に
亀裂が生じる前に１次Ｃｒ炭化物の形状を球状化すると
ともに、その周辺のＣｒ欠乏域を消失させるための熱処
理が必要であるとの結論に達したのである。Next, the method for producing the alloy of the present invention, particularly the conditions of heat treatment will be mainly described. When casting an alloy material having the above composition, it is necessary to perform heat treatment to prevent the occurrence of cracks at the corners and recesses of the product. The reason is as follows. That is, according to the conventional manufacturing method in which the material is merely cooled after casting but not heat-treated, the primary Cr carbide crystallized during solidification has a rectangular shape, and the periphery thereof is a Cr-deficient region. Discovered by others. Such a rectangular primary Cr carbide is likely to crack due to thermal stress generated during cooling, and also tends to crack at the boundary between the Cr-deficient phase and the matrix. in this way,
It was found that the cause of the cracks in the corners and recesses of the product in the conventional manufacturing method was the rectangular primary Cr carbide and the Cr-deficient region around it. Therefore, it was concluded that the heat treatment is required to make the shape of the primary Cr carbide spherical before the cracks occur in the product and to eliminate the Cr-deficient region around it.
【００２２】本発明者らは熱処理の条件を求めるために
種々の実験を重ねた結果、鋳込み後の冷却途中において
８００゜Ｃ以上の温度で１０時間以上の熱処理を施す
と、１次Ｃｒ炭化物が充分に球状化し、かつ１次Ｃｒ炭
化物の周囲のＣｒ欠乏域が消失することが判った。一
方、熱処理の温度が１０００゜Ｃを超えると、１次Ｃｒ
炭化物が溶け込み、強度低下の原因となることも判っ
た。よって、熱処理条件は、８００〜１０００゜Ｃの温
度範囲で１０時間以上とした。As a result of various experiments conducted by the inventors of the present invention in order to determine the heat treatment conditions, when heat treatment is performed for 10 hours or more at a temperature of 800 ° C. or higher during cooling after casting, primary Cr carbides are formed. It was found that the particles were sufficiently spheroidized and the Cr-deficient region around the primary Cr carbide disappeared. On the other hand, when the heat treatment temperature exceeds 1000 ° C, the primary Cr
It was also found that the carbides melted in and caused a decrease in strength. Therefore, the heat treatment condition is set to be in the temperature range of 800 to 1000 ° C. for 10 hours or more.
【００２３】なお、冷却速度が早すぎると熱処理の前に
１次Ｃｒ炭化物自体やＣｒ欠乏域と素地との間で亀裂が
発生することが考えられるので、冷却速度は熱応力を小
さくするために３０゜Ｃ／時間以下にすることが望まし
い。If the cooling rate is too fast, cracks may occur between the primary Cr carbide itself or the Cr-deficient region and the base material before the heat treatment. Therefore, the cooling rate is set to reduce the thermal stress. It is desirable to set it to 30 ° C / hour or less.
【００２４】[0024]
【実施例】次に、この発明の実施例について説明する。
この発明の組成をもつ鋳造Ｆｅ−Ｃｒ−Ｎｉ合金と、こ
の発明の組成を有しない比較合金との化学組成（重量
％）を表１に示し、それぞれの合金について行った高温
引張試験の結果を表２に示す。EXAMPLES Next, examples of the present invention will be described.
The chemical composition (wt%) of the cast Fe-Cr-Ni alloy having the composition of the present invention and the comparative alloy not having the composition of the present invention is shown in Table 1, and the results of the high temperature tensile test performed for each alloy are shown. It shows in Table 2.
【００２５】[0025]
【表１】 [Table 1]
【００２６】[0026]
【表２】 [Table 2]
【００２７】各合金のうち比較合金Ａ１，Ａ２および本
発明合金Ｂ２については、大気誘導炉により各３００Ｋ
ｇを溶解して砂型にて鋳造し、他の合金Ｂ１，Ｂ３〜Ｂ
５、およびＡ３〜Ａ５については高周波誘導炉により各
５Ｋｇを溶解して砂型にて鋳造した。表２の高温引張試
験に用いた試験片は、中央平行部の直径が５ｍｍ、長さ
１６ｍｍであり、１０００゜Ｃで７．５％／ｍｉｎの歪
速度で行った。Among the alloys, the comparative alloys A1 and A2 and the alloy B2 of the present invention were each heated to 300K by an air induction furnace.
Melt g and cast in a sand mold to make other alloys B1, B3-B
For 5 and A3 to A5, 5 kg of each was melted in a high frequency induction furnace and cast in a sand mold. The test piece used in the high temperature tensile test in Table 2 had a diameter of the central parallel portion of 5 mm and a length of 16 mm, and was performed at 1000 ° C. at a strain rate of 7.5% / min.
【００２８】この高温引張試験から明らかなように、比
較合金Ａ１（ＨＫ−２０材），Ａ２（ＨＰ−４０材），
Ａ３（低Ｗ材）は、いずれもＷの含有量が本発明の範囲
に満たないため、本発明合金Ｂ１〜Ｂ５に比べて高温強
度が劣っていることが判る。なお、比較合金Ａ４，Ａ５
については、Ｗの含有量が本発明の範囲内であるため本
発明合金並の高温強度を有している。しかしながら、比
較合金Ａ４，Ａ５はＡｌまたはＣａの含有量が本発明の
範囲を超えるため、後述する金型の製造試験で割れが発
生しており、いずれにしても本発明の目的を達成するに
至っていない。As is clear from this high temperature tensile test, comparative alloys A1 (HK-20 material), A2 (HP-40 material),
It is understood that all of A3 (low W materials) have a W content less than the range of the present invention, and therefore are inferior in high temperature strength to the alloys B1 to B5 of the present invention. Comparative alloys A4 and A5
With respect to No. 3, since the content of W is within the range of the present invention, it has high temperature strength comparable to that of the alloy of the present invention. However, since the comparative alloys A4 and A5 have a content of Al or Ca exceeding the range of the present invention, cracks have occurred in the mold manufacturing test described later, and in any case, the purpose of the present invention can be achieved. I haven't arrived.
【００２９】次に、本発明の代表的合金Ｂ２についてク
リープ破断試験を行った結果を、比較合金Ａ１，Ａ２と
対比して表３に示す。ここで、本発明合金Ｂ２について
は、鋳込み後の冷却過程において８００゜Ｃで３０時間
の熱処理を行った。試験片は、中央平行部の直径が６ｍ
ｍ、長さが３０ｍｍであり、試験は９００゜Ｃで３．０
６Ｋｇｆと、９８２゜Ｃで３．０６Ｋｇｆの各条件で行
った。Next, the results of the creep rupture test performed on the representative alloy B2 of the present invention are shown in Table 3 in comparison with the comparative alloys A1 and A2. Here, the alloy B2 of the present invention was heat-treated at 800 ° C. for 30 hours in the cooling process after casting. The diameter of the parallel part of the test piece is 6m
m, length 30 mm, test at 900 ° C 3.0
6 Kgf and 3.06 Kgf at 982 ° C.
【００３０】[0030]
【表３】 [Table 3]
【００３１】このクリープ破断試験から明らかなよう
に、本発明合金Ｂ２は、熱処理により亀裂が生じにくい
組織に変化したため、比較合金Ａ１，Ａ２と比べてクリ
ープ破断寿命が格段に長いことが判る。As is clear from this creep rupture test, the alloy B2 of the present invention changed into a structure in which cracking was less likely to occur due to heat treatment, and thus it was found that the creep rupture life was significantly longer than that of the comparative alloys A1 and A2.
【００３２】次に、本発明合金と比較合金により表４に
示す方法で金型を製造した。また、製造した金型の割れ
の発生状況を表５に示す。この製造試験から、鋳込み後
の冷却過程で熱処理を行わない場合には、比較合金Ａ１
の場合を除いて全てコーナー部や凹部に割れが発生し、
本発明の熱処理を行うと比較合金Ａ４，Ａ５の場合を除
いて全て割れが発生しないことが判る。本発明の熱処理
をしながら比較合金Ａ４，Ａ５で割れが発生したのは、
前述の通り、ＡｌまたはＣａの含有量が本発明の範囲を
超えているために靱性が低いからである。また、比較合
金Ａ１では本発明の熱処理をしなくても割れが発生して
いないが、この比較合金Ａ１（ＨＫ−２０）は従来から
コーナー部や凹部での割れという問題はなく、高温強度
が問題となっていたものである。Next, a die was manufactured from the alloy of the present invention and the comparative alloy by the method shown in Table 4. Table 5 shows the occurrence of cracks in the manufactured mold. From this production test, when the heat treatment is not performed in the cooling process after casting, the comparative alloy A1
In all cases, cracks occur in the corners and recesses,
It can be seen that when the heat treatment of the present invention is performed, no cracks occur except for the comparative alloys A4 and A5. The reason why cracking occurred in Comparative Alloys A4 and A5 during the heat treatment of the present invention was
This is because, as described above, the toughness is low because the content of Al or Ca exceeds the range of the present invention. Further, the comparative alloy A1 did not crack even if it was not subjected to the heat treatment of the present invention, but the comparative alloy A1 (HK-20) did not have the problem of cracking at the corners or recesses and has a high temperature strength. That was the problem.
【００３３】[0033]
【表４】 [Table 4]
【００３４】[0034]
【表５】 [Table 5]
【００３５】[0035]
【発明の効果】以上説明したように本発明の鋳造Ｆｅ−
Ｃｒ−Ｎｉ合金は、例えば１０００゜Ｃ程度の高温であ
っても高い強度を有する。また、本発明の製造方法によ
れば、鋳込み後の冷却過程で所定の熱処理を行うので、
製品のコーナー部や凹部での割れの発生を防止すること
ができる。したがって、本発明により例えば恒温鍛造金
型や超塑性成形用金型を構成することにより、鋳造時に
割れの発生がなく、しかも使用中の変形や磨耗を少なく
することができその寿命を向上させることができる。As described above, the cast Fe-of the present invention
The Cr-Ni alloy has high strength even at a high temperature of about 1000 ° C, for example. Further, according to the manufacturing method of the present invention, since the predetermined heat treatment is performed in the cooling process after casting,
It is possible to prevent the occurrence of cracks at the corners and recesses of the product. Therefore, by constructing, for example, a constant temperature forging die or a superplastic forming die according to the present invention, cracking does not occur during casting, and further deformation and wear during use can be reduced and the life thereof can be improved. You can
Claims (3)
１．５ｗｔ％，Ｍｎ：≦１．５ｗｔ％，Ｐ：≦０．０３
％，Ｓ：≦０．００５ｗｔ％，Ｎｉ：２０〜４０ｗｔ
％，Ｃｒ：２０〜４０ｗｔ％，Ｗ：０．３〜３．０ｗｔ
％，Ａｌ：０．００１〜０．０４ｗｔ％，Ｃａ：０．０
０１〜０．０１ｗｔ％，Ｎ：０．０１〜０．２ｗｔ％を
含有し、残部は実質的にＦｅからなることを特徴とする
高温強度に優れる鋳造Ｆｅ−Ｃｒ−Ｎｉ合金。1. C: 0.05 to 1.0 wt%, Si: ≦
1.5 wt%, Mn: ≤ 1.5 wt%, P: ≤ 0.03
%, S: 0.005 wt%, Ni: 20-40 wt
%, Cr: 20-40 wt%, W: 0.3-3.0 wt
%, Al: 0.001 to 0.04 wt%, Ca: 0.0
A cast Fe-Cr-Ni alloy excellent in high-temperature strength, characterized by containing 01 to 0.01 wt% and N: 0.01 to 0.2 wt%, and the balance being substantially Fe.
１．５ｗｔ％，Ｍｎ：≦１．５ｗｔ％，Ｐ：≦０．０３
％，Ｓ：≦０．００５ｗｔ％，Ｎｉ：２０〜４０ｗｔ
％，Ｃｒ：２０〜４０ｗｔ％，Ｗ：０．３〜３．０ｗｔ
％，Ａｌ：０．００１〜０．０４ｗｔ％，Ｃａ：０．０
０１〜０．０１ｗｔ％，Ｎ：０．０１〜０．２ｗｔ％を
含有し、残部は実質的にＦｅからなる合金素材を鋳込
み、その後８００〜１０００゜Ｃの温度範囲まで徐冷し
た後に、上記温度範囲で１０時間以上の熱処理を行うこ
とを特徴とする高温強度に優れる鋳造Ｆｅ−Ｃｒ−Ｎｉ
合金を用いた製品の製造方法。2. C: 0.05 to 1.0 wt%, Si: ≦
1.5 wt%, Mn: ≤ 1.5 wt%, P: ≤ 0.03
%, S: 0.005 wt%, Ni: 20-40 wt
%, Cr: 20-40 wt%, W: 0.3-3.0 wt
%, Al: 0.001 to 0.04 wt%, Ca: 0.0
The alloy material containing 01 to 0.01 wt% and N: 0.01 to 0.2 wt% and the balance being substantially Fe is cast and then slowly cooled to a temperature range of 800 to 1000 ° C. Cast Fe-Cr-Ni excellent in high temperature strength characterized by performing heat treatment for 10 hours or more in a temperature range
A method of manufacturing a product using an alloy.
度で行うことを特徴とする請求項２に記載の高温強度に
優れる鋳造Ｆｅ−Ｃｒ−Ｎｉ合金を用いた製品の製造方
法。3. The method for producing a product using a cast Fe—Cr—Ni alloy excellent in high temperature strength according to claim 2, wherein the slow cooling is performed at a cooling rate of 30 ° C./hour or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4513394A JP2844419B2 (en) | 1994-02-18 | 1994-02-18 | Cast Fe-Cr-Ni alloy excellent in high-temperature strength and method of manufacturing product using the same |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP4513394A JP2844419B2 (en) | 1994-02-18 | 1994-02-18 | Cast Fe-Cr-Ni alloy excellent in high-temperature strength and method of manufacturing product using the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH07228955A true JPH07228955A (en) | 1995-08-29 |
| JP2844419B2 JP2844419B2 (en) | 1999-01-06 |
Family
ID=12710784
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP4513394A Expired - Fee Related JP2844419B2 (en) | 1994-02-18 | 1994-02-18 | Cast Fe-Cr-Ni alloy excellent in high-temperature strength and method of manufacturing product using the same |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2844419B2 (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5976275A (en) * | 1995-09-01 | 1999-11-02 | Mitsubishi Jukogyo Kabushiki Kaisha | High-nickel austenitic stainless steel resistant to degradation by neutron irradiation |
| KR100897143B1 (en) * | 2002-07-26 | 2009-05-14 | 주식회사 포스코 | Method of manufacturing high Ni alloy steel with good surface quality |
| JP2014208875A (en) * | 2013-03-22 | 2014-11-06 | トヨタ自動車株式会社 | Austenitic heat-resistant cast steel and method for producing the same |
-
1994
- 1994-02-18 JP JP4513394A patent/JP2844419B2/en not_active Expired - Fee Related
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5976275A (en) * | 1995-09-01 | 1999-11-02 | Mitsubishi Jukogyo Kabushiki Kaisha | High-nickel austenitic stainless steel resistant to degradation by neutron irradiation |
| KR100897143B1 (en) * | 2002-07-26 | 2009-05-14 | 주식회사 포스코 | Method of manufacturing high Ni alloy steel with good surface quality |
| JP2014208875A (en) * | 2013-03-22 | 2014-11-06 | トヨタ自動車株式会社 | Austenitic heat-resistant cast steel and method for producing the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2844419B2 (en) | 1999-01-06 |
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