JP2002167655A - Stainless cast steel having excellent heat resistance and machinability - Google Patents
Stainless cast steel having excellent heat resistance and machinabilityInfo
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- JP2002167655A JP2002167655A JP2001247389A JP2001247389A JP2002167655A JP 2002167655 A JP2002167655 A JP 2002167655A JP 2001247389 A JP2001247389 A JP 2001247389A JP 2001247389 A JP2001247389 A JP 2001247389A JP 2002167655 A JP2002167655 A JP 2002167655A
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- heat resistance
- cast steel
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Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、耐熱性および被削
性にすぐれたステンレス鋳鋼に関する。本発明のステン
レス鋳鋼は、エンジンの排気マニホルド、タービンハウ
ジング、これらの結合部、排ガス浄化装置用部品など
の、高温において繰り返し加熱される部品の材料として
好適である。TECHNICAL FIELD The present invention relates to a cast stainless steel having excellent heat resistance and machinability. The cast stainless steel of the present invention is suitable as a material for components that are repeatedly heated at a high temperature, such as an exhaust manifold of an engine, a turbine housing, a connection portion thereof, and a component for an exhaust gas purification device.
【０００２】[0002]
【従来の技術】従来、自動車エンジンの排気マニホルド
などの耐熱性が要求される部品の材料としては、一般に
球状黒鉛鋳鉄が使用されており、排気温度がとくに高い
ものに対しては、ニレジスト鋳鉄（Ｃ：２．５〜３．０
％、Ｓｉ：１．４〜１．８％、Ｃｕ：６〜８％、Ｎｉ：
１３〜１６％、Ｃｒ：１．５〜２．４％、Ｆｅ：残部）
や、フェライト系ステンレス鋳鋼（ＪＩＳ Ｇ ＳＣ１
〜ＳＣ３）が採用されている。2. Description of the Related Art Conventionally, spheroidal graphite cast iron is generally used as a material for parts requiring heat resistance, such as an exhaust manifold of an automobile engine. C: 2.5 to 3.0
%, Si: 1.4 to 1.8%, Cu: 6 to 8%, Ni:
13 to 16%, Cr: 1.5 to 2.4%, Fe: balance)
Or ferritic stainless cast steel (JIS G SC1
To SC3).
【０００３】近年、エンジンの高効率化が要求され、そ
のため排ガスの温度がより高温になり、また自動車の排
ガス規制がより厳しくなっているため、排ガスをより高
温で取り扱う必要が生じている。上記した既存の材料を
エンジンの排ガス処理機器用部品に使用すると、変形、
熱疲労割れなどが発生し、使用できない。使用温度が９
５０℃以上になると、強度の点で、フェライト系ステン
レス鋳鋼はもはや使用できないため、オーステナイト系
ステンレス鋳鋼が使用されてきた。しかし、既知のオー
ステナイト系ステンレス鋳鋼は、クリープ強度の向上に
主眼を置いたものが多く、繰り返し加熱を受ける部品に
要求される熱疲労に焦点を合わせたものは少ない。特開
昭５４−９６４１８号に開示された耐熱鋳鋼が知られて
いるに止まる。[0003] In recent years, high efficiency of engines has been demanded, and as a result, the temperature of exhaust gas has become higher, and exhaust gas regulations for automobiles have become more stringent. Therefore, it has become necessary to handle exhaust gas at higher temperature. When the above-mentioned existing materials are used for exhaust gas treatment equipment parts of engines, deformation,
Thermal fatigue cracks occur and cannot be used. Operating temperature is 9
When the temperature exceeds 50 ° C., ferritic cast stainless steel can no longer be used in terms of strength, and austenitic cast stainless steel has been used. However, many of the known cast austenitic stainless steels focus on improving the creep strength, and few focus on the thermal fatigue required for components that are repeatedly heated. Only the heat-resistant cast steel disclosed in JP-A-54-96418 is known.
【０００４】上記の公開公報に記載されているステンレ
ス耐熱鋳鋼は、Ｃ：０．１〜１．５％、Ｓｉ：０．５〜
５．０％、Ｍｎ：２．５％以下、Ｎｉ：８〜４５％、Ｃ
ｒ：１５〜３５％、Ｗ：０．５〜３．０％、必要に応じ
てＭｏ：０．５〜２．０％またはＳ：０．０５〜０．２
５％を含有し、Ｆｅ：残部という合金組成であって、こ
の鋼は、耐熱疲労特性はすぐれたものであるが、９５０
℃以上の高温における引張強さが十分でなく、また被削
性が不満足であるから、これらの点について改良が望ま
れていた。[0004] The stainless steel heat-resistant cast steel described in the above-mentioned publications has a C content of 0.1 to 1.5% and a Si content of 0.5 to 1.5%.
5.0%, Mn: 2.5% or less, Ni: 8 to 45%, C
r: 15 to 35%, W: 0.5 to 3.0%, Mo: 0.5 to 2.0% or S: 0.05 to 0.2 as required.
This steel has an alloy composition of 5% and Fe: balance. Although this steel has excellent heat fatigue resistance, it has an alloy composition of 950%.
Since the tensile strength at a high temperature of not less than ℃ is not sufficient and the machinability is unsatisfactory, improvement in these points has been desired.
【０００５】発明者らは、この要望に応えるために研究
し、オーステナイト系ステンレス鋳鋼において、Ｃ，Ｎ
ｉ，Ｃｒ，ＷおよびＮｂの含有量を特定の範囲に選択す
ることにより、高温強度、熱疲労強度および耐酸化性が
すぐれたものとなること、および、Ｓｅを含有させるこ
とにより、Ｓ含有量を少なくしても、被削性を改善でき
ること、などを知った。[0005] The present inventors have studied to meet this demand and found that C, N in austenitic stainless cast steel are used.
By selecting the contents of i, Cr, W and Nb in a specific range, the high-temperature strength, the thermal fatigue strength and the oxidation resistance are improved, and by including Se, the S content is increased. It was found that machinability could be improved even if the amount was reduced.
【０００６】[0006]
【発明が解決しようとする課題】本発明の目的は、この
ような発明者らの得た新しい知見にもとづいて上記の問
題を解決し、９５０℃以上の高温で使用することができ
る高い耐熱性を有するとともに、すぐれた被削性をもつ
オーステナイト系ステンレス鋳鋼を提供することにあ
る。SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems based on such new findings obtained by the inventors and to provide a high heat resistance which can be used at a high temperature of 950 ° C. or more. Another object of the present invention is to provide an austenitic stainless steel cast steel having excellent machinability.
【０００７】[0007]
【課題を解決するための手段】本発明の耐熱性および被
削性にすぐれたステンレス鋳鋼は、基本的な合金組成と
して、重量％で、Ｃ：０．２〜０．４％、Ｓｉ：０．５
〜２．０％、Ｍｎ：０．５〜２．０％、Ｐ：０．１０％
以下、Ｓ：０．０４〜０．２％、Ｎｉ：８．０〜４２．
０％、Ｃｒ：１５．０〜２８．０％、Ｗ：０．５〜７．
０％、Ｎｂ：０．５〜２．０％、Ａｌ：０．０２％以
下、Ｔｉ：０．０５％以下、Ｎ：０．１５％以下および
Ｓｅ：０．００１〜０．５０％を含有し、残部がＦｅお
よび不可避の不純物からなる。The cast stainless steel of the present invention having excellent heat resistance and machinability has, as a basic alloy composition, 0.2 to 0.4% by weight of C, and 0: 0% by weight. .5
To 2.0%, Mn: 0.5 to 2.0%, P: 0.10%
Hereinafter, S: 0.04 to 0.2%, Ni: 8.0 to 42.
0%, Cr: 15.0-28.0%, W: 0.5-7.
0%, Nb: 0.5 to 2.0%, Al: 0.02% or less, Ti: 0.05% or less, N: 0.15% or less, and Se: 0.001 to 0.50% The balance consists of Fe and unavoidable impurities.
【０００８】[0008]
【発明の実施の形態】本発明の耐熱性および被削性にす
ぐれたステンレス鋳鋼は、上記の基本的な合金成分に加
えて、下記のグループに属する任意添加元素の一つまた
は両方を含有することができる。 Ｉ）Ｍｏ：２．０％以下、Ｚｒ：０．０５％以下、Ｂ：
０．１０％以下、およびＣｏ：１０．０％以下の１種ま
たは２種以上、ならびに II）Ｃａ：０．１０％以下およびＲＥＭ：０．５０％以
下の１種または２種。BEST MODE FOR CARRYING OUT THE INVENTION The cast stainless steel having excellent heat resistance and machinability according to the present invention contains, in addition to the above basic alloy components, one or both of optional elements belonging to the following groups. be able to. I) Mo: 2.0% or less, Zr: 0.05% or less, B:
0.10% or less, and one or more of Co: 10.0% or less, and II) one or two of Ca: 0.10% or less and REM: 0.50% or less.
【０００９】本発明の耐熱性および被削性にすぐれたス
テンレス鋳鋼において、成分組成を上記のように特定し
た理由を以下に説明する。The reason why the component composition of the cast stainless steel according to the present invention having excellent heat resistance and machinability is specified as described above will be described below.
【００１０】Ｃ：０．２〜０．４％ Ｃは、Ｎｂ、Ｗなどと結合して炭化物を生成し、高温強
度および熱疲労強度を向上させる。この効果を得るため
には、０．２％以上含有させる必要があるが、０．４％
を超えると、ＣがＣｒと結合してマトリクス中のＣｒ濃
度を低下させて、合金の耐酸化性を低くする。好ましい
Ｃ含有量は、０．２５〜０．３３％である。C: 0.2-0.4% C combines with Nb, W, etc. to form carbides and improves high-temperature strength and thermal fatigue strength. To obtain this effect, it is necessary to contain 0.2% or more, but 0.4%
When C is exceeded, C bonds with Cr to lower the Cr concentration in the matrix, thereby lowering the oxidation resistance of the alloy. The preferred C content is 0.25 to 0.33%.
【００１１】Ｓｉ：０．５〜２．０％ Ｓｉは、耐酸化性および溶湯の流動性を向上させる。こ
の効果は０．５％以上の含有で得られるが、２．０％を
超えて含有させると、オーステナイト組織の安定性が低
下するとともに、靭性が低下する。Si: 0.5-2.0% Si improves the oxidation resistance and the fluidity of the molten metal. This effect can be obtained with a content of 0.5% or more. However, when the content exceeds 2.0%, the stability of the austenite structure is reduced and the toughness is reduced.
【００１２】Ｍｎ：０．５〜２．０％ Ｍｎは、耐酸化性を向上させるとともに、ＳおよびＳｅ
と化合して介在物を生じ、それが被削性を向上させる働
きがある。この効果を得るには、０．５％以上含有させ
る必要があるが、２．０％を超えて含有させると、靭性
が低下する。好ましい含有量は、０．８〜１．５％であ
る。 Ｐ：０．１０％以下 Ｐは、被削性に寄与する成分であるが、０．１０％を超
える存在は耐酸化性および靱延性を著しく低下させるの
で、含有量をそれ以下に抑える。Mn: 0.5 to 2.0% Mn improves the oxidation resistance, and improves the S and Se properties.
To form inclusions, which serve to improve machinability. To obtain this effect, the content needs to be 0.5% or more, but if it exceeds 2.0%, the toughness decreases. The preferred content is 0.8-1.5%. P: 0.10% or less P is a component that contributes to machinability, but the presence of more than 0.10% significantly lowers oxidation resistance and toughness, so the content is suppressed to less than 0.10%.
【００１３】Ｓ：０．０４〜０．２％ Ｓは、Ｍｎと化合してＭｎＳを生成し、被削性を向上さ
せる。この効果を与えるＳ量は、最低０．０４％であ
る。０．２％を超えるＳ量は、靭性および延性を著しく
低下させる。好ましいＳ含有量は、０．０６〜０．１４
％である。S: 0.04 to 0.2% S combines with Mn to form MnS and improves machinability. The amount of S giving this effect is at least 0.04%. If the S content exceeds 0.2%, the toughness and ductility are significantly reduced. Preferred S content is 0.06 to 0.14.
%.
【００１４】Ｎｉ：８．０〜４２．０％ Ｎｉは、マトリクスのオーステナイト相を安定化させ、
合金の耐熱性および耐食性を向上させる。そこで、この
鋼にはＮｉ：８．０％以上を添加する。多量に添加して
も効果が飽和するし、コストの上昇を招くので、４２％
を上限として定めた。好ましい含有量は、１０〜４０％
である。Ni: 8.0-42.0% Ni stabilizes the austenite phase of the matrix,
Improves heat resistance and corrosion resistance of the alloy. Therefore, Ni: 8.0% or more is added to this steel. Even if a large amount is added, the effect is saturated and the cost is increased.
Was set as the upper limit. Preferred content is 10 to 40%
It is.
【００１５】Ｃｒ：１５．０〜２８．０％ Ｃｒは、Ｃと結合して炭化物を生成し、高温強度および
耐酸化性を高める。この利益は、１５．０％以上の添加
で得られる。より高い添加量においては、効果が飽和
し、さらに、脆化相であるσ相の生成を促進するので、
２８．０％を上限とする。好ましい含有量は、１９〜２
６％である。Cr: 15.0 to 28.0% Cr combines with C to form a carbide and enhances high-temperature strength and oxidation resistance. This benefit is obtained with 15.0% or more addition. At a higher addition amount, the effect saturates and further promotes the formation of the σ phase, which is an embrittlement phase,
The upper limit is 28.0%. The preferred content is 19-2.
6%.
【００１６】Ｗ：０．５〜７．０％ Ｗは、Ｃと結合して炭化物を生成し、高温強度および熱
疲労特性を顕著に改善する。Ｗの炭化物形成能はＣｒの
それより大きいため、マトリクスのオーステナイト相に
存在するＣｒの量が減少することを防止し、耐酸化性を
高く保つのに役立つ。このＷの効果は、０．５％以上の
添加で得られる。あまり多量の添加は、耐酸化性および
靭−延性を低下させる。この観点から、７．０％を上限
として設けた。好ましい含有量は、１〜６％である。W: 0.5-7.0% W combines with C to form carbides and significantly improves high-temperature strength and thermal fatigue properties. Since the ability of W to form carbides is greater than that of Cr, it helps prevent the amount of Cr present in the austenite phase of the matrix from decreasing and keeps the oxidation resistance high. This effect of W can be obtained by adding 0.5% or more. Too much addition reduces oxidation resistance and toughness-ductility. From this viewpoint, the upper limit is set to 7.0%. The preferred content is 1 to 6%.
【００１７】Ｎｂ：０．５〜２．０％ Ｎｂは、Ｗと同様にＣと結合して炭化物を生成し、高温
強度および熱疲労特性を顕著に改善する。Ｎｂの炭化物
形成能も、Ｗと同様に、Ｃｒのそれよりも高いため、マ
トリクスを構成するオーステナイト相中のＣｒ量が低下
することを防止し、耐酸化性を高く保つ。この効果を得
るには、少なくとも０．５％のＮｂを含有させる必要が
ある。一方、多量のＮｂは共晶炭化物を多量に晶出さ
せ、その結果、靭−延性が低下するので、２．０％以下
の添加に止める。好ましいＮｂ含有量は、０．９〜１．
７％である。Nb: 0.5 to 2.0% Nb combines with C like W to form carbides, and significantly improves high-temperature strength and thermal fatigue properties. The carbide forming ability of Nb is also higher than that of Cr, like W, so that the Cr content in the austenite phase constituting the matrix is prevented from lowering, and the oxidation resistance is kept high. To obtain this effect, it is necessary to contain at least 0.5% of Nb. On the other hand, a large amount of Nb causes a large amount of eutectic carbide to be crystallized, and as a result, the toughness and ductility decrease. The preferred Nb content is 0.9-1.
7%.
【００１８】Ａｌ：０．０２％以下 Ａｌは、耐酸化性の向上に寄与する。０．０２％を超え
る添加は、溶湯の流動性を悪くし、かつ靱−延性を著し
く低下させる。Al: 0.02% or less Al contributes to improvement of oxidation resistance. Addition exceeding 0.02% deteriorates the fluidity of the molten metal and significantly lowers the toughness-ductility.
【００１９】Ｔｉ：０．０５％以下 Ｔｉは、Ｃと結合して炭化物を生成し、高温強度および
熱疲労特性の向上に寄与する。過剰に添加すると、Ｃと
結合するＴｉ量が多くなるため、ＮｂおよびＷと結合す
るＣの量が少なくなる。ＮｂおよびＷの炭化物量の減少
は、高温強度および熱疲労特性を低下させる。そこで、
Ｔｉの添加量は、０．０５％を上限とする。Ti: 0.05% or less Ti combines with C to form carbides, and contributes to improvement in high-temperature strength and thermal fatigue characteristics. If it is added in excess, the amount of Ti binding to C increases, and the amount of C binding to Nb and W decreases. The reduction in the amount of carbides of Nb and W reduces the high-temperature strength and thermal fatigue properties. Therefore,
The upper limit of the amount of Ti added is 0.05%.
【００２０】Ｎ：０．１５％以下 Ｎは、強度およびオーステナイト組織の安定性の向上に
寄与する。Ｎ含有量が０．１５％を超えると、熱疲労特
性および靭延性が低下する。N: 0.15% or less N contributes to improvement of strength and stability of austenite structure. If the N content exceeds 0.15%, the thermal fatigue properties and toughness and ductility decrease.
【００２１】Ｓｅ：０．００１〜０．５０％ Ｓｅは、Ｓと同様にＭｎと結合して介在物を生成し、被
削性を向上させるために必要な元素である。その作用は
０．００１％という少量でも認められるが、０．５０％
を超えると、高温強度、靭延性および熱疲労特性が低下
する。コストも高くなる。Se: 0.001 to 0.50% Se is an element necessary for improving the machinability by combining with Mn to form inclusions like S. Its effect can be seen in as little as 0.001%, but 0.50%
If it exceeds 300, the high-temperature strength, toughness and ductility and thermal fatigue properties are reduced. Costs are also high.
【００２２】上記の基本的な合金組成に対して任意に添
加することができる成分の作用と、その組成範囲の限定
理由は、つぎのとおりである。The effects of the components that can be arbitrarily added to the above basic alloy composition and the reasons for limiting the composition range are as follows.
【００２３】Ｍｏ：２．０％以下 Ｍｏは、オーステナイト相中に固溶して高温強度を向上
させる。多量になると、９００℃以上の温度における耐
酸化性が著しく低下するとともに、靭延性が低下するの
で、Ｍｏ添加量は、２．０％以下にする。好ましい含有
量は、１．８％以下である。Mo: 2.0% or less Mo improves the high-temperature strength by forming a solid solution in the austenite phase. When the amount is large, the oxidation resistance at a temperature of 900 ° C. or more is remarkably reduced, and the toughness and ductility are reduced. The preferred content is 1.8% or less.
【００２４】Ｚｒ：０．０５％以下 Ｚｒは、結晶粒および共晶炭化物の粗大化を抑制し、高
温強度および熱疲労特性を向上させる。多量の添加は靭
−延性を著しく低下させるので、その含有量の上限を、
０．０５％とした。Zr: 0.05% or less Zr suppresses coarsening of crystal grains and eutectic carbides, and improves high-temperature strength and thermal fatigue properties. Since the addition of a large amount significantly reduces the toughness-ductility, the upper limit of the content,
0.05%.
【００２５】Ｃｏ：１０．０％以下 Ｃｏは、オーステナイト組織を安定性し、固溶強化によ
り高温強度を高め、また耐食性も向上させる。これらの
効果は次第に飽和し、１０．０％を超える添加は意義を
失う。コストも上昇する。Co: 10.0% or less Co stabilizes the austenite structure, increases the high-temperature strength by solid solution strengthening, and improves the corrosion resistance. These effects gradually become saturated, and additions above 10.0% lose significance. Costs also rise.
【００２６】Ｂ：０．１０％以下 Ｂは、結晶粒界を強化し、高温強度を向上させる。０．
１０％を超える多量の添加は、鋼の耐酸化性および靱−
延性を著しく低下させ、熱疲労特性をも低下させる。B: 0.10% or less B strengthens crystal grain boundaries and improves high-temperature strength. 0.
A large amount of addition of more than 10% can reduce the oxidation resistance and toughness of steel.
It significantly reduces ductility and also reduces thermal fatigue properties.
【００２７】Ｃａ：０．１０％以下 Ｃａは、Ｏと結合して酸化物を生成し、被削性を向上さ
せる。０．１０％を超えるＣａの添加は、靱−延性を低
下させ、熱疲労特性を著しく低下させる。Ca: 0.10% or less Ca combines with O to form an oxide and improves machinability. Addition of more than 0.10% of Ca lowers toughness-ductility and significantly lowers thermal fatigue properties.
【００２８】ＲＥＭ：０．５０％以下 ＲＥＭは、鋼の耐酸化性を向上させる。０．５０％を超
える添加は靭−延性を低下させる、熱疲労特性を著しく
低下させる。REM: 0.50% or less REM improves the oxidation resistance of steel. Addition of more than 0.50% lowers toughness-ductility and significantly lowers thermal fatigue properties.
【００２９】[0029]
【実施例】表１（実施例）および表２（比較例）に示し
た合金組成のステンレス鋳鋼を、高周波誘導炉を用いて
溶製し、ＪＩＳ−Ａ号試験片に鋳込んだ。これに、１１
００℃に３０分間加熱する焼鈍を施した後、高温引張り
試験片、熱疲労試験片および被削性試験片を採取した。
それらの試験片を対象に、下記の方法および条件で、高
温引張り試験、熱疲労試験および被削性試験を行なっ
た。その結果を表３（実施例）および表４（比較例）に
示す。EXAMPLES Stainless cast steels having the alloy compositions shown in Table 1 (Examples) and Table 2 (Comparative Examples) were melted using a high-frequency induction furnace and cast into JIS-A test pieces. In addition, 11
After annealing at 00 ° C. for 30 minutes, high-temperature tensile test pieces, thermal fatigue test pieces and machinability test pieces were collected.
A high-temperature tensile test, a thermal fatigue test and a machinability test were performed on these test pieces under the following method and conditions. The results are shown in Table 3 (Example) and Table 4 (Comparative Example).
【００３０】［高温引張り試験］標点間距離３０mm、直
径６mmの試験片を用いて、１０５０℃で実施した。 ［熱疲労試験］直径６０mm、厚さ１０mmの円盤型試験片
を、１０５０℃のアルミナ媒体流動床炉に３分間浸漬し
た後、速やかに１５０℃のアルミナ媒体流動床炉へ移し
て４分間浸漬するサイクルを５００回繰り返した後の、
延べ割れ長さ。 ［被削性試験］超硬チップを取り付けた切削工具を用い
てフライス加工を行ない、超硬チップの摩耗量が２００
μmになるまでの切削長さ。結果は、代表的なオーステ
ナイ系ステンレス鋳鋼であるＨＫ４０（比較例５）のデ
ータと対比して表した。[High Temperature Tensile Test] The test was conducted at 1050 ° C. using a test piece having a gauge length of 30 mm and a diameter of 6 mm. [Thermal Fatigue Test] A disk-shaped test piece having a diameter of 60 mm and a thickness of 10 mm was immersed in an alumina medium fluidized bed furnace at 1050 ° C. for 3 minutes, and then immediately transferred to an alumina medium fluidized bed furnace at 150 ° C. and immersed for 4 minutes. After repeating the cycle 500 times,
Total crack length. [Machinability test] Milling was performed using a cutting tool having a carbide tip attached, and the wear amount of the carbide tip was 200
Cutting length to μm. The results are shown in comparison with data of HK40 (Comparative Example 5) which is a typical austenitic stainless cast steel.
【００３１】 [0031]
【００３２】 [0032]
【００３３】[0033]
【表３】実施例 [Table 3] Examples
【００３４】[0034]
【表４】比較例 [Table 4] Comparative example
【００３５】表４のデータにみる各比較例の問題は、つ
ぎの理由による。まず比較例１は、Ｓ含有量が低すぎる
ために、高温引張強さは良好であるが、被削性が不十分
である。比較例２は、Ｓ含有量が多過ぎるために、被削
性は良好であるが、高温引張強さが十分でない。比較例
３は、ＷおよびＮｂの含有量が低いために、高温引張強
さが低い。一方、比較例４は、ＷおよびＮｂ含有量が多
過ぎるために、高温引張強さは良好であるものの、熱疲
労による割れが発生しやすい。比較例５は、ＷもＮｂも
含有していないし、またＳ含有量も低いために高温引張
強さが低く、かつ被削性が十分でない。比較例６は、Ｎ
ｉ含有量が少量すぎて、高温引張強さが低く、割れも発
生しやすい。比較例７も、Ｃｒ含有量が不足であるた
め、やはり高温引張強さと割れに関して劣っている。The problems of each comparative example as seen in the data of Table 4 are as follows. First, in Comparative Example 1, although the S content was too low, the high-temperature tensile strength was good, but the machinability was insufficient. In Comparative Example 2, since the S content was too large, the machinability was good, but the high-temperature tensile strength was not sufficient. Comparative Example 3 has a low high-temperature tensile strength because the contents of W and Nb are low. On the other hand, in Comparative Example 4, although the W and Nb contents were too large, the high-temperature tensile strength was good, but cracks due to thermal fatigue were likely to occur. Comparative Example 5 contains neither W nor Nb and has a low S content, so that the high-temperature tensile strength is low and the machinability is not sufficient. Comparative Example 6
The i content is too small, the high-temperature tensile strength is low, and cracks are likely to occur. Comparative Example 7 is also inferior in high temperature tensile strength and cracking due to insufficient Cr content.
【００３６】これに対して、本発明の実施例１〜１９
は、いずれも比較例にくらべて１０５０℃における高温
引張強さおよび熱疲労特性にすぐれ、かつ被削性も良好
であって、ＨＫ４０の被削性を基準にしたとき、２倍以
上の工具寿命を示すことが確認された。In contrast, Examples 1 to 19 of the present invention
Are excellent in high-temperature tensile strength at 1050 ° C. and thermal fatigue properties at 1050 ° C. as compared with the comparative examples, and also have good machinability. Was confirmed.
【００３７】[0037]
【発明の効果】本発明のステンレス鋳鋼は、前記した合
金組成を選択したことにより、９５０℃以上においても
引張強さおよび熱疲労特性がともに良好であり、さらに
従来のオーステナイト系ステンレス鋳鋼に比べて約２倍
またはそれ以上の被削性が得られるという、すぐれた効
果を奏する。The cast stainless steel of the present invention has good tensile strength and good thermal fatigue properties even at 950 ° C. or higher by selecting the above alloy composition, and further has a higher strength than conventional austenitic cast stainless steel. An excellent effect is obtained in that machinability of about twice or more is obtained.
Claims (4)
ｉ：０．５〜２．０％、Ｍｎ：０．５〜２．０％、Ｐ：
０．１０％以下、Ｓ：０．０４〜０．２％、Ｎｉ：８．
０〜４２．０％、Ｃｒ：１５．０〜２８．０％、Ｗ：
０．５〜７．０％、Ｎｂ：０．５〜２．０％、Ａｌ：
０．０２％以下、Ｔｉ：０．０５％以下、Ｎ：０．１５
％以下およびＳｅ：０．００１〜０．５０％を含有し、
残部がＦｅおよび不可避な不純物からなる合金組成を有
する耐熱性および被削性にすぐれたステンレス鋳鋼。1. C .: 0.2 to 0.4% by weight, S
i: 0.5 to 2.0%, Mn: 0.5 to 2.0%, P:
0.10% or less, S: 0.04 to 0.2%, Ni: 8.
0 to 42.0%, Cr: 15.0 to 28.0%, W:
0.5-7.0%, Nb: 0.5-2.0%, Al:
0.02% or less, Ti: 0.05% or less, N: 0.15
% And Se: 0.001 to 0.50%
A cast stainless steel with excellent heat resistance and machinability having an alloy composition consisting of Fe and unavoidable impurities.
ｉ：０．５〜２．０％、Ｍｎ：０．５〜２．０％、Ｐ：
０．１０％以下、Ｓ：０．０４〜０．２％、Ｎｉ：８．
０〜４２．０％、Ｃｒ：１５．０〜２８．０％、Ｗ：
０．５〜７．０％、Ｎｂ：０．５〜２．０％、Ａｌ：
０．０２％以下、Ｔｉ：０．０５％以下、Ｎ：０．１５
％以下およびＳｅ：０．００１〜０．５０％を含有し、
さらにＭｏ：２．０％以下、Ｚｒ：０．０５％以下、
Ｂ：０．１０％以下およびＣｏ：１０．０％以下の１種
または２種以上を含有し、残部がＦｅおよび不可避な不
純物からなる合金組成を有する耐熱性および被削性にす
ぐれたステンレス鋳鋼。2. C: 0.2 to 0.4% by weight, S
i: 0.5 to 2.0%, Mn: 0.5 to 2.0%, P:
0.10% or less, S: 0.04 to 0.2%, Ni: 8.
0 to 42.0%, Cr: 15.0 to 28.0%, W:
0.5-7.0%, Nb: 0.5-2.0%, Al:
0.02% or less, Ti: 0.05% or less, N: 0.15
% And Se: 0.001 to 0.50%
Further, Mo: 2.0% or less, Zr: 0.05% or less,
B: Cast stainless steel containing one or more of 0.10% or less and Co: 10.0% or less, and having an alloy composition composed of Fe and unavoidable impurities, with excellent heat resistance and machinability. .
ｉ：０．５〜２．０％、Ｍｎ：０．５〜２．０％、Ｐ：
０．１０％以下、Ｓ：０．０４〜０．２％、Ｎｉ：８．
０〜４２．０％、Ｃｒ：１５．０〜２８．０％、Ｗ：
０．５〜７．０％、Ｎｂ：０．５〜２．０％、Ａｌ：
０．０２％以下、Ｔｉ：０．０５％以下、Ｎ：０．１５
％以下およびＳｅ：０．００１〜０．５０％を含有し、
さらにＣａ：０．１０％以下およびＲＥＭ：０．５０％
以下の１種または２種を含有し、残部がＦｅおよび不可
避な不純物からなる合金組成を有する耐熱性および被削
性にすぐれたステンレス鋳鋼。3. C: 0.2 to 0.4% by weight, S
i: 0.5 to 2.0%, Mn: 0.5 to 2.0%, P:
0.10% or less, S: 0.04 to 0.2%, Ni: 8.
0 to 42.0%, Cr: 15.0 to 28.0%, W:
0.5-7.0%, Nb: 0.5-2.0%, Al:
0.02% or less, Ti: 0.05% or less, N: 0.15
% And Se: 0.001 to 0.50%
Further, Ca: 0.10% or less and REM: 0.50%
A cast stainless steel having excellent heat resistance and machinability, having one or two of the following alloys and an alloy composition consisting of Fe and unavoidable impurities.
ｉ：０．５〜２．０％、Ｍｎ：０．５〜２．０％、Ｐ：
０．１０％以下、Ｓ：０．０４〜０．２％、Ｎｉ：８．
０〜４２．０％、Ｃｒ：１５．０〜２８．０％、Ｗ：
０．５〜７．０％、Ｎｂ：０．５〜２．０％、Ａｌ：
０．０２％以下、Ｔｉ：０．０５％以下、Ｎ：０．１５
％以下およびＳｅ：０．００１〜０．５０％を含有し、
さらにＭｏ：２．０％以下、Ｚｒ：０．０５％以下、
Ｂ：０．１０％以下およびＣｏ：１０．０％以下の１種
または２種以上を含有し、かつ、Ｃａ：０．１０％以下
およびＲＥＭ：０．５０％以下の１種または２種を含有
し、残部がＦｅおよび不可避な不純物からなる合金組成
を有する耐熱性および被削性にすぐれたステンレス鋳
鋼。4. C: 0.2 to 0.4% by weight, S
i: 0.5 to 2.0%, Mn: 0.5 to 2.0%, P:
0.10% or less, S: 0.04 to 0.2%, Ni: 8.
0 to 42.0%, Cr: 15.0 to 28.0%, W:
0.5-7.0%, Nb: 0.5-2.0%, Al:
0.02% or less, Ti: 0.05% or less, N: 0.15
% And Se: 0.001 to 0.50%
Further, Mo: 2.0% or less, Zr: 0.05% or less,
B: 0.10% or less and Co: one or two or more of 10.0% or less, and Ca: 0.10% or less and REM: 0.50% or less A cast stainless steel with excellent heat resistance and machinability, containing an alloy composition consisting of Fe and unavoidable impurities.
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| US7238005B2 (en) | 2003-07-30 | 2007-07-03 | Kabushiki Kaisha Toshiba | Steam turbine power plant |
| KR100821329B1 (en) * | 2007-11-23 | 2008-04-11 | (주)씨에프 이엔티 | Carburizing alloy steel excellent in high-temperature strength |
| CN104131236A (en) * | 2014-07-28 | 2014-11-05 | 宁国市开源电力耐磨材料有限公司 | Chromium nickel nitrogen rare-earth wear-resistant and heat-resistant steel |
| JPWO2012176887A1 (en) * | 2011-06-22 | 2015-02-23 | 株式会社Ihi | Multistage supercharging system |
| WO2018016878A1 (en) * | 2016-07-22 | 2018-01-25 | (주)계양정밀 | Heat-resistant cast steel for turbocharger turbine housing, requiring less tungsten, and turbocharger turbine housing using same |
| JP2020511594A (en) * | 2017-02-28 | 2020-04-16 | サン−ゴバン セバ | Alloys for fiber forming plates |
| JPWO2021009807A1 (en) * | 2019-07-12 | 2021-01-21 | ||
| CN114717464A (en) * | 2022-02-25 | 2022-07-08 | 温州市海格阀门有限公司 | Heat-resistant cast stainless steel and preparation method thereof |
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