JP2015096648A - Ferritic stainless steel - Google Patents
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Abstract
Description
本発明は、Ｃｒ含有鋼に係り、とくに自動車やオートバイの排気管やコンバータケース、火力発電プラントの排気ダクト等の高温下で使用される排気系部材に用いて好適な、優れた熱疲労特性、耐酸化性を兼ね備えたフェライト系ステンレス鋼に関するものである。 The present invention relates to Cr-containing steel, and particularly excellent thermal fatigue characteristics suitable for use in exhaust system members used at high temperatures such as exhaust pipes and converter cases of automobiles and motorcycles, exhaust ducts of thermal power plants, The present invention relates to a ferritic stainless steel having oxidation resistance.
自動車のエキゾーストマニホールドや排気パイプ、コンバータケース、マフラー等の排気系部材には、耐酸化性に優れるほか、熱疲労特性や高温疲労特性（以下、これらをまとめて「耐熱性」と呼ぶ。）にも優れることが要求されている。ここで、上記熱疲労とは、エンジンの始動・停止に伴って排気系部材は加熱・冷却を繰り返し受けるが、上記部材は周辺の部品との関係で拘束された状態にあるため、熱膨張・収縮が制限されて素材自体に熱歪が発生し、この熱歪に起因した疲労現象のことをいう。また、上記高温疲労とは、エンジン稼動中には、排気系部材は加熱された状態で振動を受け続けるが、この振動による歪の蓄積に起因した疲労現象のことをいう。前者は低サイクル疲労、後者は高サイクル疲労であり、全く異なった疲労現象である。 Exhaust system members such as automobile exhaust manifolds, exhaust pipes, converter cases, and mufflers have excellent oxidation resistance, thermal fatigue characteristics, and high temperature fatigue characteristics (hereinafter collectively referred to as "heat resistance"). It is required to be excellent. Here, the thermal fatigue means that the exhaust system member repeatedly receives heating and cooling as the engine is started and stopped, but the member is in a state of being restrained in relation to surrounding parts, This refers to a fatigue phenomenon caused by thermal strain generated in the material itself due to limited shrinkage. The high-temperature fatigue refers to a fatigue phenomenon caused by accumulation of strain due to vibration, while the exhaust system member continues to receive vibration while the engine is running. The former is low cycle fatigue and the latter is high cycle fatigue, which are completely different fatigue phenomena.
上記特性が求められる部材に用いられる素材としては、現在、ＮｂとＳｉを添加したＴｙｐｅ４２９（１４Ｃｒ−０．９Ｓｉ−０．４Ｎｂ系）のようなＣｒ含有鋼が多く使用されている。しかし、エンジン性能の向上に伴い、排ガス温度が９００℃を超えるような温度まで上昇してくると、Ｔｙｐｅ４２９では要求特性、特に熱疲労特性を十分に満たすことができなくなってきている。 Currently, Cr-containing steel such as Type 429 (14Cr-0.9Si-0.4Nb system) to which Nb and Si are added is often used as a material used for members that require the above characteristics. However, if the exhaust gas temperature rises to a temperature exceeding 900 ° C. as the engine performance is improved, Type 429 cannot sufficiently satisfy the required characteristics, particularly thermal fatigue characteristics.
この問題に対応できる素材として、例えば、ＮｂとＭｏを添加して高温耐力を向上させたＣｒ含有鋼や、ＪＩＳ Ｇ４３０５に規定されるＳＵＳ４４４（１９Ｃｒ−０．４Ｎｂ−２Ｍｏ）、Ｎｂ、Ｍｏ、Ｗを添加したフェライト系ステンレス鋼等が開発されている（例えば、特許文献１参照）。しかし、昨今における排ガス高温化の趨勢によりＳＵＳ４４４でも耐熱性が不足する場合があり、ＳＵＳ４４４を超える耐熱性を有する材料の開発が要求されるようになってきている。 As a material that can cope with this problem, for example, Cr-containing steel in which high temperature proof stress is improved by adding Nb and Mo, SUS444 (19Cr-0.4Nb-2Mo), Nb, Mo, W, as defined in JIS G4305 Ferritic stainless steel and the like to which is added have been developed (see, for example, Patent Document 1). However, due to the recent trend of increasing the temperature of exhaust gas, heat resistance may be insufficient even in SUS444, and development of a material having heat resistance exceeding SUS444 has been demanded.
ＳＵＳ４４４を超える耐熱性を有する材料としては、例えば、特許文献２〜８には、ＳＵＳ４４４にＣｕを添加し、Ｃｕの析出強化を活用し熱疲労特性を高めた材料が開示されている。 As materials having heat resistance exceeding SUS444, for example, Patent Documents 2 to 8 disclose materials in which Cu is added to SUS444 and the thermal fatigue characteristics are enhanced by utilizing Cu precipitation strengthening.
一方、Ａｌを積極的に添加することによって、耐熱性の向上を図る技術も提案されている。例えば、特許文献９〜１３には、Ａｌの添加によって高温強度や耐酸化性を高めたフェライト系ステンレス鋼が開示されている。 On the other hand, a technique for improving heat resistance by actively adding Al has also been proposed. For example, Patent Documents 9 to 13 disclose ferritic stainless steel whose high temperature strength and oxidation resistance are enhanced by the addition of Al.
発明者らの研究によれば、特許文献２〜８に開示された鋼のように、Ｃｕを添加して耐熱性を改善しようとした場合には、熱疲労特性は向上するものの、鋼自身の耐酸化性が却って低下するため、排ガスのますますの高温化の趨勢には対応できない。 According to the researches of the inventors, as in the steels disclosed in Patent Documents 2 to 8, when adding Cu to improve heat resistance, the thermal fatigue characteristics are improved, but the steel itself Oxidation resistance decreases on the contrary, and it cannot cope with the trend of higher exhaust gas temperatures.
また、特許文献９〜１３に開示された鋼は、Ａｌ添加によって高い高温強度や優れた耐酸化性を得ているが、Ａｌ添加は鋼の熱膨張係数を増加させるため、昇温と降温が繰り返される熱疲労特性が低下してしまう問題がある。 Moreover, although the steel disclosed by patent documents 9-13 has acquired the high high temperature strength and the outstanding oxidation resistance by Al addition, since Al addition increases the thermal expansion coefficient of steel, temperature rise and temperature fall are There is a problem that the repeated thermal fatigue characteristics are degraded.
また、Ｍｏ添加鋼に対して８５０℃を超える熱疲労試験を行った場合、ＭｏとＣｒを含む第二相（σ相）が粗大に析出し、却って熱疲労寿命が低下してしまうことが明らかとなってきた。 Moreover, when the thermal fatigue test exceeding 850 degreeC is performed with respect to Mo addition steel, it is clear that the 2nd phase ((sigma) phase) containing Mo and Cr precipitates coarsely and a thermal fatigue life falls on the contrary. It has become.
本発明はかかる課題を解決し、Ｃｕを添加した場合の耐酸化性の低下を防止し、かつＡｌを添加した場合の熱膨張係数の増加を低減し、さらにＭｏを添加した場合の第二相（σ相）の析出を抑制した、耐酸化性および熱疲労特性に優れるフェライト系ステンレス鋼を提供することを目的とする。なお、本発明の「耐酸化性および熱疲労特性に優れる」とは、ＳＵＳ４４４より優れた特性を有することであり、具体的には、耐酸化性は１１００℃における耐酸化性が、また、熱疲労特性は２００℃−９５０℃間で昇温と降温を繰り返したときの熱疲労特性が、ＳＵＳ４４４より優れていることをいう。 The present invention solves this problem, prevents a decrease in oxidation resistance when Cu is added, reduces an increase in thermal expansion coefficient when Al is added, and further adds the second phase when Mo is added. An object of the present invention is to provide a ferritic stainless steel excellent in oxidation resistance and thermal fatigue properties in which precipitation of (σ phase) is suppressed. In the present invention, “excellent in oxidation resistance and thermal fatigue characteristics” means having characteristics superior to SUS444. Specifically, oxidation resistance is oxidation resistance at 1100 ° C. The fatigue property means that the thermal fatigue property is superior to SUS444 when the temperature is raised and lowered between 200 ° C and 950 ° C.
発明者らは、Ｃｕ、Ａｌ、およびＭｏを添加した鋼において、Ｃｕ添加による耐酸化性の低下を防止し、Ａｌ添加による熱膨張係数の増加を抑制し、さらにＭｏ添加による第二相の析出を抑制することを検討した。そして、耐酸化性、熱疲労特性のいずれもがＳＵＳ４４４より優れたフェライト系ステンレス鋼を開発するべく鋭意検討を重ねた。 The inventors have prevented the decrease in oxidation resistance due to the addition of Cu in the steel added with Cu, Al, and Mo, suppressed the increase of the thermal expansion coefficient due to the addition of Al, and further precipitated the second phase due to the addition of Mo. We studied to suppress this. And, in order to develop a ferritic stainless steel that is superior to SUS444 in both oxidation resistance and thermal fatigue characteristics, intensive studies were made.
その結果、Ｎｂを０．０２〜１．０％、Ｍｏを０．１〜６．０％、Ｃｕを０．４〜４．０％の範囲で複合添加することによって、幅広い温度域で高温強度が上昇し、熱疲労特性が向上することを見出した。また、Ａｌを０．０５〜６．０％の範囲で添加することによって、Ｃｕ添加による耐酸化性の低下を防止し、優れた耐酸化性が得られるのみならず、高温強度も大きく増加することを見出した。さらに、Ａｌ添加による熱膨張係数の増加は適正量のＣｏ添加により抑制できること、Ｍｏ添加による第二相の析出はＡｌ添加により抑制できることを見出し、本発明を完成するに至った。 As a result, Nb is 0.02 to 1.0%, Mo is 0.1 to 6.0%, and Cu is added in the range of 0.4 to 4.0%. It has been found that the thermal fatigue characteristics are improved. Moreover, by adding Al in the range of 0.05 to 6.0%, it is possible to prevent a decrease in oxidation resistance due to the addition of Cu and not only provide excellent oxidation resistance, but also greatly increase high-temperature strength. I found out. Furthermore, it has been found that the increase in the thermal expansion coefficient due to the addition of Al can be suppressed by adding an appropriate amount of Co, and that the precipitation of the second phase due to the addition of Mo can be suppressed by the addition of Al, thereby completing the present invention.
本発明は以上の知見に基づいてなされたものであり、以下を要旨とするものである。
［１］ｍａｓｓ％で、Ｃ：０．０２０％以下、Ｓｉ：０．１超〜３．０％、Ｍｎ：２．０％以下、Ｐ：０．０５０％以下、Ｓ：０．０１０％以下、Ａｌ：０．０５〜６．０％、Ｎ：０．０２０％以下、Ｃｒ：１２〜３０％、Ｃｕ：０．４〜４．０％、Ｎｂ：０．０２〜１．０％、Ｔｉ：０．０１〜１．０％、Ｍｏ：０．１〜６．０％、Ｃｏ：０．０１〜３．０％、Ｎｉ：０．０２〜１．０％、かつ、Ｓｉ＋Ａｌ≧０．５０を満たして含有し、残部がＦｅおよび不可避的不純物からなることを特徴とするフェライト系ステンレス鋼。
［２］ｍａｓｓ％で、Ｃ：０．０２０％以下、Ｓｉ：０．１超〜３．０％、Ｍｎ：２．０％以下、Ｐ：０．０５０％以下、Ｓ：０．０１０％以下、Ａｌ：０．０５〜６．０％、Ｎ：０．０２０％以下、Ｃｒ：１２〜３０％、Ｃｕ：０．４〜４．０％、Ｎｂ：０．０２〜１．０％、Ｔｉ：０．０１〜１．０％、Ｍｏ：０．１超〜６．０％、Ｃｏ：０．０１〜３．０％、Ｎｉ：０．０２〜１．０％、かつ、Ｓｉ＋Ａｌ≧０．５０を満たして含有し、残部がＦｅおよび不可避的不純物からなることを特徴とするフェライト系ステンレス鋼。
［３］前記［１］または［２］において、ｍａｓｓ％で、さらに、Ｂ：０．０００２〜０．０１００％、Ｚｒ：０．００５〜１．０％、Ｖ：０．０１〜１．０％、Ｗ：０．０１〜５．０％のうちから選ばれる１種または２種以上を含むことを特徴とするフェライト系ステンレス鋼。
［４］前記［１］〜［３］のいずれかにおいて、ｍａｓｓ％で、さらに、Ｃａ：０．０００２〜０．００５０％、Ｍｇ：０．０００２〜０．００５０％のうちから選ばれる１種または２種を含むことを特徴とするフェライト系ステンレス鋼。
なお、本明細書において、鋼の成分を示す％はすべてｍａｓｓ％である。
This invention is made | formed based on the above knowledge, and makes the following a summary.
[1] In mass%, C: 0.020% or less, Si: more than 0.1 to 3.0%, Mn: 2.0% or less, P: 0.050% or less, S: 0.010% or less , Al: 0.05 to 6.0%, N: 0.020% or less, Cr: 12 to 30%, Cu: 0.4 to 4.0%, Nb: 0.02 to 1.0%, Ti : 0.01-1.0%, Mo: 0.1-6.0%, Co: 0.01-3.0%, Ni: 0.02-1.0%, and Si + Al ≧ 0.50 A ferritic stainless steel characterized by containing and containing Fe and inevitable impurities.
[2] In mass%, C: 0.020% or less, Si: more than 0.1 to 3.0%, Mn: 2.0% or less, P: 0.050% or less, S: 0.010% or less , Al: 0.05 to 6.0%, N: 0.020% or less, Cr: 12 to 30%, Cu: 0.4 to 4.0%, Nb: 0.02 to 1.0%, Ti : 0.01 to 1.0%, Mo: more than 0.1 to 6.0%, Co: 0.01 to 3.0%, Ni: 0.02 to 1.0%, and Si + Al ≧ 0. 50. A ferritic stainless steel containing 50 and containing Fe and inevitable impurities.
[3] In the above [1] or [2], in mass%, B: 0.0002 to 0.0100%, Zr: 0.005 to 1.0%, V: 0.01 to 1.0 %, W: Ferritic stainless steel containing one or more selected from 0.01 to 5.0%.
[4] In any one of the above [1] to [3], in mass%, one selected from Ca: 0.0002 to 0.0050% and Mg: 0.0002 to 0.0050% Or ferritic stainless steel characterized by including 2 types.
In addition, in this specification, all% which shows the component of steel is mass%.
本発明によれば、ＳＵＳ４４４（ＪＩＳ Ｇ４３０５）より優れる熱疲労特性および耐酸化性を有するフェライト系ステンレス鋼を提供することができる。したがって、本発明の鋼は、自動車等の排気系部材に好適に用いることができる。 According to the present invention, it is possible to provide a ferritic stainless steel having thermal fatigue characteristics and oxidation resistance superior to those of SUS444 (JIS G4305). Therefore, the steel of the present invention can be suitably used for exhaust system members such as automobiles.
以下、本発明を詳細に説明する。
本発明のフェライト系ステンレス鋼は、ｍａｓｓ％で、Ｃ：０．０２０％以下、Ｓｉ：０．１超〜３．０％、Ｍｎ：２．０％以下、Ｐ：０．０５０％以下、Ｓ：０．０１０％以下、Ｃｒ：１２〜３０％、Ｎｉ：０．０２〜１．０％、Ａｌ：０．０５〜６．０％、Ｎ：０．０２０％以下、Ｃｕ：０．４〜４．０％、Ｎｂ：０．０２〜１．０％、Ｔｉ：０．０１〜１．０％、Ｍｏ：０．１〜６．０％、Ｃｏ：０．０１〜３．０％、かつ、Ｓｉ＋Ａｌ≧０．５０を満たして含有し、残部がＦｅおよび不可避的不純物からなる。本発明では、成分組成のバランスが非常に重要であり、このような成分組成の組み合わせとすることで、Ｃｕ添加による耐酸化性の低下を防止し、Ａｌ添加による熱膨張係数の増加を抑制し、さらにＭｏ添加による第二相の析出を抑制し、耐酸化性および熱疲労特性がＳＵＳ４４４より優れたフェライト系ステンレス鋼を得ることができる。
Hereinafter, the present invention will be described in detail.
The ferritic stainless steel of the present invention is mass%, C: 0.020% or less, Si: more than 0.1 to 3.0%, Mn: 2.0% or less, P: 0.050% or less, S : 0.010% or less, Cr: 12-30%, Ni: 0.02-1.0%, Al: 0.05-6.0%, N: 0.020% or less, Cu: 0.4- 4.0%, Nb: 0.02-1.0%, Ti: 0.01-1.0%, Mo: 0.1-6.0%, Co: 0.01-3.0%, and , Si + Al ≧ 0.50 is satisfied, and the balance consists of Fe and inevitable impurities. In the present invention, the balance of the component composition is very important. By using such a combination of component compositions, the decrease in oxidation resistance due to the addition of Cu is prevented, and the increase in the thermal expansion coefficient due to the addition of Al is suppressed. Further, precipitation of the second phase due to the addition of Mo can be suppressed, and a ferritic stainless steel having oxidation resistance and thermal fatigue characteristics superior to SUS444 can be obtained.
次に、本発明のフェライト系ステンレス鋼の成分組成について説明する。
Ｃ：０．０２０％以下
Ｃは、鋼の強度を高めるのに有効な元素であるが、０．０２０％を超えて添加すると、靭性および成形性の低下が顕著となる。よって、Ｃは０．０２０％以下とする。なお、Ｃは、成形性を確保する観点からは０．０１０％以下が好ましい。また、排気系部材としての強度を確保する観点からは０．００１％以上が好ましい。より好ましくは０．００３〜０．００８％の範囲である。
Next, the component composition of the ferritic stainless steel of the present invention will be described.
C: 0.020% or less C is an element effective for increasing the strength of steel, but if added over 0.020%, the deterioration of toughness and formability becomes significant. Therefore, C is made 0.020% or less. In addition, C is preferably 0.010% or less from the viewpoint of securing moldability. Further, from the viewpoint of ensuring the strength as an exhaust system member, 0.001% or more is preferable. More preferably, it is 0.003 to 0.008% of range.
Ｓｉ：０．１超〜３．０％
Ｓｉは、耐酸化性向上のために必要な重要元素である。Ｃｕ添加により低下した耐酸化性を改善するためには０．１％超えの添加が必要である。一方、３．０％を超える過剰の添加は、加工性を低下させるので、上限は３．０％とする。好ましくは０．３超〜２．０％の範囲である。より好ましくは０．５超〜１．５％の範囲である。
Si: more than 0.1 to 3.0%
Si is an important element necessary for improving oxidation resistance. In order to improve the oxidation resistance lowered by the addition of Cu, addition exceeding 0.1% is necessary. On the other hand, excessive addition exceeding 3.0% lowers the workability, so the upper limit is made 3.0%. Preferably, it is in the range of more than 0.3 to 2.0%. More preferably, it is in the range of more than 0.5 to 1.5%.
Ｍｎ：２．０％以下
Ｍｎの過剰な添加は、高温でγ相が生成しやすくなり、耐熱性を低下させる。よって、Ｍｎは２．０％以下とする。一方、Ｍｎは、脱酸剤として、また、鋼の強度を高めるために添加される元素である。また、酸化スケールの耐剥離性を高める効果も有する。これらの効果を得るためには、０．０５％以上の添加が好ましい。より好ましくは０．２超〜１．０％の範囲である。さらに好ましくは０．５超〜０．６％の範囲である。
Mn: 2.0% or less Excessive addition of Mn tends to generate a γ-phase at high temperatures, thereby reducing heat resistance. Therefore, Mn is made 2.0% or less. On the other hand, Mn is an element added as a deoxidizer and to increase the strength of steel. Moreover, it also has the effect of increasing the peel resistance of the oxide scale. In order to obtain these effects, addition of 0.05% or more is preferable. More preferably, it is in the range of more than 0.2 to 1.0%. More preferably, it is in the range of more than 0.5 to 0.6%.
Ｐ：０．０５０％以下
Ｐは、鋼の靭性を低下させる有害な元素であり、可能な限り低減するのが望ましい。よって、Ｐは０．０５０％以下とする。好ましくは０．０３０％以下である。
P: 0.050% or less P is a harmful element that lowers the toughness of steel, and is desirably reduced as much as possible. Therefore, P is made 0.050% or less. Preferably it is 0.030% or less.
Ｓ：０．０１０％以下
Ｓは、伸びやｒ値を低下させ、成形性に悪影響を及ぼすとともに、ステンレス鋼の基本特性である耐食性を低下させる有害元素でもあるため、できる限り低減するのが望ましい。よって、本発明では、Ｓは０．０１０％以下とする。好ましくは０．００５％以下である。
S: 0.010% or less S is a harmful element that lowers elongation and r value, adversely affects formability, and lowers corrosion resistance, which is a basic characteristic of stainless steel, so it is desirable to reduce it as much as possible. . Therefore, in the present invention, S is made 0.010% or less. Preferably it is 0.005% or less.
Ａｌ：０．０５〜６．０％
Ａｌは、Ｃｕ添加の鋼において耐酸化性を向上させるのに必要不可欠な元素である。特に、本発明ではＳＵＳ４４４を超える耐酸化性と熱疲労特性を得ることを目的とする。さらに、本発明のようにＭｏが添加されている鋼においては，Ａｌは熱疲労試験中のＭｏを含む第二相（σ相）の析出を抑制する効果も有する。第二相が析出すると固溶Ｍｏ量の減少により後述するような固溶強化効果が得られなくなるのみならず、短時間で粗大化して亀裂発生の起点となってしまう。これらの効果を得るためにＡｌは０．０５％以上の添加が必要である。一方、６．０％を超えて添加すると、耐酸化性向上効果が飽和するのみならず、鋼が硬質化して加工性が低下してしまう。よって、Ａｌは０．０５〜６．０％の範囲とする。好ましくは０．２５超〜５．０％の範囲である。より好ましくは０．５０超〜４．０％の範囲である。さらに好ましくは２．０超〜３．０％の範囲である。
Al: 0.05-6.0%
Al is an indispensable element for improving oxidation resistance in Cu-added steel. In particular, it is an object of the present invention to obtain oxidation resistance and thermal fatigue characteristics that exceed SUS444. Furthermore, in steel to which Mo is added as in the present invention, Al also has an effect of suppressing the precipitation of the second phase (σ phase) containing Mo during the thermal fatigue test. When the second phase is precipitated, the solid solution strengthening effect as described later cannot be obtained due to the decrease in the amount of solid solution Mo, and it becomes coarse in a short time and becomes a starting point of crack generation. In order to obtain these effects, it is necessary to add 0.05% or more of Al. On the other hand, if added over 6.0%, not only the oxidation resistance improving effect is saturated but also the steel becomes hard and workability is lowered. Therefore, Al is taken as 0.05 to 6.0% of range. Preferably, it is in the range of more than 0.25 to 5.0%. More preferably, it is in the range of more than 0.50 to 4.0%. More preferably, it is in the range of more than 2.0 to 3.0%.
Ｓｉ＋Ａｌ≧０．５０
上述したように、ＳｉとＡｌは耐酸化性向上に有効な元素である。それぞれ０．１％超、０．０５％以上の添加でその効果が認められる。しかし、本発明の目的であるＳＵＳ４４４を超える耐酸化性を実現するためには、両元素を所定の範囲で添加した上で、少なくともＳｉ＋Ａｌ≧０．５０％を満たす必要がある。好ましくはＳｉ＋Ａｌ≧１．０％である。より好ましくはＳｉ＋Ａｌ≧２．０％である。
Si + Al ≧ 0.50
As described above, Si and Al are effective elements for improving oxidation resistance. The effect is recognized by adding more than 0.1% and 0.05% or more, respectively. However, in order to realize oxidation resistance exceeding SUS444, which is the object of the present invention, it is necessary to satisfy at least Si + Al ≧ 0.50% after adding both elements in a predetermined range. Preferably, Si + Al ≧ 1.0%. More preferably, Si + Al ≧ 2.0%.
Ｎ：０．０２０％以下
Ｎは、鋼の靭性および成形性を低下させる元素であり、０．０２０％を超えて含有すると、靭性および成形性の低下が顕著となる。よって、Ｎは０．０２０％以下とする。なお、Ｎは、靭性、成形性を確保する観点からは、できるだけ低減するのが好ましく、０．０１０％未満とするのが望ましい。
N: 0.020% or less N is an element that lowers the toughness and formability of steel. When the content exceeds 0.020%, the toughness and formability are significantly reduced. Therefore, N is set to 0.020% or less. Note that N is preferably reduced as much as possible from the viewpoint of securing toughness and moldability, and is preferably less than 0.010%.
Ｃｒ：１２〜３０％
Ｃｒは、ステンレス鋼の特徴である耐食性、耐酸化性を向上させるのに有効な重要元素であるが、１２％未満では、十分な耐酸化性が得られない。一方、Ｃｒは、室温において鋼を固溶強化し、硬質化、低延性化する元素であり、特に３０％を超えて添加すると、上記弊害が顕著となるので、上限は３０％とする。好ましくは１４〜２５％の範囲である。より好ましくは１８超〜２２％の範囲である。
Cr: 12-30%
Cr is an important element effective for improving the corrosion resistance and oxidation resistance, which are the characteristics of stainless steel, but if it is less than 12%, sufficient oxidation resistance cannot be obtained. On the other hand, Cr is an element that solidifies and strengthens steel at room temperature, hardens, and lowers ductility. Particularly, when added in excess of 30%, the above-described adverse effects become remarkable, so the upper limit is made 30%. Preferably it is 14 to 25% of range. More preferably, it is in the range of more than 18 to 22%.
Ｃｕ：０．４〜４．０％
Ｃｕは、熱疲労特性の向上に非常に有効な元素であり、その効果は０．４％以上の添加で現れる。しかし、４．０％を超える添加は、熱処理後の冷却時にε−Ｃｕ相が析出し、鋼を硬質化するとともに、熱間加工時に脆化を起こしやすくする。さらに、Ｃｕの添加は、熱疲労特性を向上させるものの、鋼自身の耐酸化性を却って低下し、総体的に見て耐熱性が低下してしまうことがある。この原因は、十分に明らかとはなっていないが、生成したスケール直下の脱Ｃｒ層にＣｕが濃化し、ステンレス鋼本来の耐酸化性を向上する元素であるＣｒの再拡散を抑制するためと考えられる。よって、これらの理由により、上限は４．０％とする。好ましくは０．７〜３．０％の範囲である。より好ましくは１．０超〜２．０％の範囲である。
Cu: 0.4-4.0%
Cu is an element that is very effective in improving thermal fatigue characteristics, and the effect is manifested by addition of 0.4% or more. However, addition exceeding 4.0% precipitates the ε-Cu phase during cooling after the heat treatment, hardens the steel, and easily causes embrittlement during hot working. Furthermore, although the addition of Cu improves the thermal fatigue characteristics, the oxidation resistance of the steel itself is decreased, and the heat resistance may decrease as a whole. The cause of this is not sufficiently clear, but it is because Cu concentrates in the deCr layer formed directly under the scale, and suppresses the re-diffusion of Cr, which is an element that improves the original oxidation resistance of stainless steel. Conceivable. Therefore, for these reasons, the upper limit is set to 4.0%. Preferably it is 0.7 to 3.0% of range. More preferably, it is in the range of more than 1.0 to 2.0%.
Ｎｂ：０．０２〜１．０％
Ｎｂは、Ｃ、Ｎと炭窒化物を形成して固定し、耐食性や成形性、溶接部の耐粒界腐食性を高める作用を有するとともに、高温強度を上昇させて熱疲労特性を向上させる元素である。このような効果は、０．０２％以上の添加で認められる。しかし、１．０％を超える添加は、Ｌａｖｅｓ相が析出しやすくなり、脆化を促進する。よって、Ｎｂは０．０２〜１．０％の範囲とする。好ましくは０．３０超〜０．８０％の範囲である。より好ましくは０．４０超〜０．５０％未満の範囲である。
Nb: 0.02 to 1.0%
Nb is an element that forms and fixes carbonitrides with C and N, has an effect of increasing corrosion resistance, formability, and intergranular corrosion resistance of welds, and increases thermal fatigue characteristics by increasing high-temperature strength. It is. Such an effect is recognized by addition of 0.02% or more. However, addition exceeding 1.0% facilitates precipitation of the Laves phase and promotes embrittlement. Therefore, Nb is set to a range of 0.02 to 1.0%. Preferably, it is in the range of more than 0.30 to 0.80%. More preferably, it is in the range of more than 0.40 to less than 0.50%.
Ｔｉ：０．０１〜１．０％
Ｔｉは、Ｎｂと同様、Ｃ、Ｎを固定して、耐食性や成形性を向上し、溶接部の粒界腐食を防止する元素である。Ｔｉを添加することにより、ＴｉがＮｂよりも優先的にＣ、Ｎと結びつくため、高温強度に有効な鋼中固溶Ｎｂ量を確保することができ、耐熱性向上に有効である。また、本発明のＡｌ添加の鋼においては、耐酸化性の向上に有効な元素であり、特に１０００℃を超える高温域で使用され、優れた耐酸化性が要求される鋼では必須の添加元素である。高温での耐酸化性を得るためには、Ｔｉは０．０１％以上添加する。一方、１．０％を超える過剰な添加は、耐酸化性向上効果が飽和するほか、靭性の低下を招いて、例えば、熱延板焼鈍ラインで繰り返し受ける曲げ−曲げ戻しによって破断を起こしたりする等、製造性に悪影響を及ぼすようになる。よって、Ｔｉの上限は１．０％とする。好ましくは０．１５超〜０．８０％の範囲である。より好ましくは０．２０超〜０．５０％の範囲である。
Ti: 0.01 to 1.0%
Ti, like Nb, is an element that fixes C and N, improves corrosion resistance and formability, and prevents intergranular corrosion of welds. By adding Ti, Ti is preferentially combined with C and N over Nb, so that it is possible to secure an amount of solute Nb in steel effective for high-temperature strength, which is effective in improving heat resistance. Further, in the steel with Al added according to the present invention, it is an element effective for improving oxidation resistance, and is an essential additive element particularly in steels that are used in a high temperature range exceeding 1000 ° C. and require excellent oxidation resistance. It is. In order to obtain oxidation resistance at a high temperature, Ti is added by 0.01% or more. On the other hand, an excessive addition exceeding 1.0% saturates the oxidation resistance improving effect and causes a decrease in toughness, for example, causing breakage due to bending-bending that is repeatedly received in a hot-rolled sheet annealing line. Etc., which will adversely affect manufacturability. Therefore, the upper limit of Ti is 1.0%. Preferably it is in the range of more than 0.15 to 0.80%. More preferably, it is in the range of more than 0.20 to 0.50%.
Ｍｏ：０．１〜６．０％
Ｍｏは、鋼中に固溶し鋼の高温強度を向上させることで熱疲労特性を向上させる有効な元素である。その効果は０．１％以上の添加で現れる。特に０．１％を超えて添加すると効果がより現れる。一方、過剰な添加は鋼を硬質化させて加工性を低下させてしまうのみならず、σ相のような粗大な金属間化合物を形成しやすくなるため却って熱疲労特性は低下してしまう。従って、上限は６．０％とする。好ましくは０．３〜５．０％の範囲である。
より好ましくは１．２超〜４．０％の範囲である。さらにより好ましくは１．４〜３．０％の範囲である。
Mo: 0.1-6.0%
Mo is an effective element that improves thermal fatigue properties by dissolving in steel and improving the high-temperature strength of the steel. The effect appears with addition of 0.1% or more. In particular, when it exceeds 0.1%, the effect becomes more apparent. On the other hand, excessive addition not only hardens the steel and lowers the workability, but also tends to form a coarse intermetallic compound such as the σ phase, so that the thermal fatigue properties are lowered. Therefore, the upper limit is 6.0%. Preferably it is 0.3 to 5.0% of range.
More preferably, it is in the range of more than 1.2 to 4.0%. Even more preferably, it is in the range of 1.4 to 3.0%.
Ｃｏ：０．０１〜３．０％
Ｃｏは、鋼の靭性向上に有効な元素として知られている。さらに、本発明ではＡｌ添加により増加した熱膨張係数を低減する元素として重要な元素でもある。これらの効果を得るためには、０．０１％以上とする。一方、過剰な添加は鋼の靭性を却って低下させるため、上限は３．０％とする。好ましくは０．０１〜０．３０未満％の範囲である。
Co: 0.01-3.0%
Co is known as an element effective for improving the toughness of steel. Furthermore, in the present invention, it is also an important element as an element for reducing the thermal expansion coefficient increased by the addition of Al. In order to obtain these effects, the content is made 0.01% or more. On the other hand, excessive addition reduces the toughness of the steel, so the upper limit is made 3.0%. Preferably it is the range of 0.01 to less than 0.30%.
Ｎｉ：０．０２〜１．０％
Ｎｉは、鋼の靭性および耐酸化性を向上させる元素である。これらの効果を得るためには、０．０２％以上の添加とする。しかし、Ｎｉは、高価であり、また、強力なγ相形成元素であるため、高温でγ相を生成し、耐酸化性を低下させる。よって、上限は１．０％とする。好ましくは０．０５〜０．８０％未満の範囲である。より好ましくは０．２超〜０．５％未満の範囲である。
Ni: 0.02-1.0%
Ni is an element that improves the toughness and oxidation resistance of steel. In order to obtain these effects, 0.02% or more is added. However, since Ni is expensive and is a strong γ-phase forming element, it generates a γ-phase at a high temperature and reduces oxidation resistance. Therefore, the upper limit is 1.0%. Preferably it is 0.05 to less than 0.80% of range. More preferably, it is in the range of more than 0.2 to less than 0.5%.
残部はＦｅおよび不可避的不純物からなる。 The balance consists of Fe and inevitable impurities.
本発明のフェライト系ステンレス鋼は、上記必須成分に加えて、さらに、Ｂ、Ｚｒ、Ｖ、Ｗのうちから選ばれる１種または２種以上を、下記の範囲で添加することができる。 In addition to the above essential components, the ferritic stainless steel of the present invention may further contain one or more selected from B, Zr, V, and W within the following range.
Ｂ：０．０００２〜０．０１００％
Ｂは、鋼の加工性、特に二次加工性を向上させるのに有効な元素である。また、本発明のようなＣｕ添加の鋼においては、Ｃｕの析出物を微細化し、析出強化を有効に活用できるようにする効果も有する。このような効果は、０．０００２％以上の添加で得ることができる。一方、過剰な添加は、ＢＮを生成して加工性を低下させる。よって、Ｂを添加する場合は、０．０００２〜０．０１００％以下とする。好ましくは０．０００５〜０．００５０％の範囲である。より好ましくは０．０００８〜０．００２０％の範囲である。
B: 0.0002 to 0.0100%
B is an element effective for improving the workability of steel, particularly the secondary workability. Moreover, in the steel with Cu added as in the present invention, there is an effect that the precipitate of Cu is refined so that precipitation strengthening can be effectively utilized. Such an effect can be obtained by adding 0.0002% or more. On the other hand, excessive addition produces BN and degrades workability. Therefore, when adding B, it is made into 0.0002 to 0.0100% or less. Preferably it is 0.0005 to 0.0050% of range. More preferably, it is 0.000 to 0.0020% of range.
Ｚｒ：０．００５〜１．０％
Ｚｒは耐酸化性を向上させる元素であり、本発明では、必要に応じて添加することができる。この効果を得るためには、０．００５％以上添加するのが好ましい。しかし、１．０％を超える添加は、Ｚｒ金属間化合物が析出して、鋼を脆化させる。よって、Ｚｒを添加する場合は、０．００５〜１．０％とする。
Zr: 0.005 to 1.0%
Zr is an element that improves the oxidation resistance, and can be added as necessary in the present invention. In order to obtain this effect, 0.005% or more is preferably added. However, addition exceeding 1.0% causes Zr intermetallic compounds to precipitate and embrittles the steel. Therefore, when adding Zr, it is 0.005 to 1.0%.
Ｖ：０．０１〜１．０％
Ｖは、鋼の加工性向上に有効な元素であるとともに、耐酸化性の向上にも有効な元素である。これらの効果は、０．０１％以上で顕著となる。しかし、１．０％を超える過剰な添加は、粗大なＶ（Ｃ、Ｎ）の析出を招き、靭性を低下させるのみならず、表面性状を低下させる。よって、Ｖを添加する場合は、０．０１〜１．０％とする。好ましくは０．０３〜０．５０％の範囲である。より好ましくは０．０５〜０．３０％の範囲である。
V: 0.01 to 1.0%
V is an element effective for improving the workability of steel and an element effective for improving oxidation resistance. These effects become significant at 0.01% or more. However, excessive addition exceeding 1.0% leads to coarse precipitation of V (C, N), not only lowering toughness but also lowering surface properties. Therefore, when adding V, it is 0.01 to 1.0%. Preferably it is 0.03 to 0.50% of range. More preferably, it is 0.05 to 0.30% of range.
Ｗ：０．０１〜５．０％
Ｗは、Ｍｏと同様に固溶強化により高温強度を大きく向上させる元素である。この効果は０．０１％以上の添加で現れる。一方、過剰な添加は鋼を著しく硬質化するのみならず、製造時の焼鈍工程において強固なスケールが生成するため、酸洗時の脱スケールが困難になる。よって、Ｗを添加する場合は、０．０１〜５．０％とする。好ましくは０．３０〜４．０％の範囲である。さらに好ましくは１．０〜４．０％の範囲である。
W: 0.01-5.0%
W, like Mo, is an element that greatly improves high-temperature strength by solid solution strengthening. This effect appears when 0.01% or more is added. On the other hand, excessive addition not only hardens the steel remarkably, but also produces a strong scale in the annealing process during production, making it difficult to descale during pickling. Therefore, when adding W, it is 0.01 to 5.0%. Preferably it is 0.30 to 4.0% of range. More preferably, it is 1.0 to 4.0% of range.
本発明のフェライト系ステンレス鋼は、さらに、Ｃａ、Ｍｇのうちから選ばれる１種または２種を、下記の範囲で添加することができる。
Ｃａ：０．０００２〜０．００５０％
Ｃａは、連続鋳造の際に発生しやすいＴｉ系介在物析出によるノズルの閉塞を防止するのに有効な成分である。０．０００２％未満ではその効果がない。一方、表面欠陥を発生させず良好な表面性状を得るためには０．００５０％以下とする必要がある。従って、Ｃａを含有する場合は、０．０００２〜０．００５０％の範囲とするこ。好ましくは０．０００５〜０．００３０％の範囲である。より好ましくは０．０００５〜０．００２０％の範囲である。
The ferritic stainless steel of the present invention can further contain one or two selected from Ca and Mg within the following range.
Ca: 0.0002 to 0.0050%
Ca is an effective component for preventing nozzle clogging due to precipitation of Ti-based inclusions that are likely to occur during continuous casting. If it is less than 0.0002%, the effect is not obtained. On the other hand, in order to obtain good surface properties without generating surface defects, the content must be 0.0050% or less. Therefore, when it contains Ca, it shall be 0.0002 to 0.0050% of range. Preferably it is 0.0005 to 0.0030% of range. More preferably, it is 0.0005 to 0.0020% of range.
Ｍｇ：０．０００２〜０．００５０％
Ｍｇはスラブの等軸晶率を向上させ、加工性や靭性の向上に有効な元素である。本発明のようにＮｂやＴｉが添加されている鋼においては、ＮｂやＴｉの炭窒化物の粗大化を抑制する効果も有する。その効果は０．０００２％以上の含有で現れる。Ｔｉ炭窒化物が粗大化すると、脆性割れの起点となるため靭性が大きく低下する。Ｎｂ炭窒化物が粗大化すると、Ｎｂの鋼中固溶量が低下するため、熱疲労特性の低下に繋がる。一方、Ｍｇ含有量が０．００５０％超えとなると、鋼の表面性状を悪化させてしまう。したがって、Ｍｇを含有する場合は、０．０００２〜０．００５０％の範囲とする。好ましくは０．０００２〜０．００３０％の範囲である。より好ましくは０．０００４〜０．００２０％の範囲である。
Mg: 0.0002 to 0.0050%
Mg is an element that improves the equiaxed crystal ratio of the slab and is effective in improving workability and toughness. The steel to which Nb and Ti are added as in the present invention also has an effect of suppressing the coarsening of Nb and Ti carbonitrides. The effect appears with a content of 0.0002% or more. When the Ti carbonitride becomes coarse, it becomes a starting point for brittle cracking, so that the toughness is greatly reduced. When Nb carbonitrides become coarse, the amount of Nb solid solution in steel decreases, leading to a decrease in thermal fatigue characteristics. On the other hand, when the Mg content exceeds 0.0050%, the surface properties of the steel are deteriorated. Therefore, when it contains Mg, it is set as 0.0002 to 0.0050% of range. Preferably it is 0.0002 to 0.0030% of range. More preferably, it is 0.0004 to 0.0020% of range.
次に、本発明のフェライト系ステンレス鋼の製造方法について説明する。
本発明のステンレス鋼の製造方法は、フェライト系ステンレス鋼の通常の製造方法であれば好適に用いることができ、特に限定されるものではない。例えば、転炉、電気炉等公知の溶解炉で鋼を溶製し、あるいはさらに取鍋精錬、真空精錬等の二次精錬を経て上述した本発明の成分組成を有する鋼とし、連続鋳造法あるいは造塊−分塊圧延法で鋼片（スラブ）とし、その後、熱間圧延、熱延板焼鈍、酸洗、冷間圧延、仕上げ焼鈍、酸洗等の各工程を経て冷延焼鈍板とする製造工程で製造することができる。上記冷間圧延は、１回または中間焼鈍を挟む２回以上の冷間圧延としてもよく、また、冷間圧延、仕上げ焼鈍、酸洗の各工程は、繰り返して行ってもよい。さらに、熱延板焼鈍は省略してもよく、鋼板の表面光沢や粗度調整が要求される場合には、冷延後あるいは仕上げ焼鈍後、スキンパス圧延を施してもよい。
Next, the manufacturing method of the ferritic stainless steel of this invention is demonstrated.
The method for producing stainless steel of the present invention can be suitably used as long as it is a normal method for producing ferritic stainless steel, and is not particularly limited. For example, the steel having the above-described composition of the present invention is obtained by melting steel in a known melting furnace such as a converter or electric furnace, or further through secondary refining such as ladle refining or vacuum refining. It is made into a steel slab (slab) by the ingot-making and ingot rolling method, and then made into a cold-rolled annealed plate through each process such as hot rolling, hot-rolled sheet annealing, pickling, cold rolling, finish annealing, pickling. It can be manufactured in a manufacturing process. The cold rolling may be performed once or two or more cold rollings with intermediate annealing interposed therebetween, and the steps of cold rolling, finish annealing, and pickling may be repeated. Furthermore, hot-rolled sheet annealing may be omitted, and skin pass rolling may be performed after cold rolling or after finish annealing when surface gloss or roughness adjustment of the steel sheet is required.
上記製造方法における、好ましい製造条件について説明する。
鋼を溶製する製鋼工程は、転炉あるいは電気炉等で溶解した鋼をＶＯＤ法等により二次精錬し、上記必須成分および必要に応じて添加される成分を含有する鋼とするのが好ましい。溶製した溶鋼は、公知の方法で鋼素材とすることができるが、生産性および品質面からは、連続鋳造法によるのが好ましい。鋼素材は、その後、好ましくは１０００〜１２５０℃に加熱され、熱間圧延により所望の板厚の熱延板とされる。もちろん、板材以外に熱間加工することもできる。上記熱延板は、その後必要に応じて６００〜８００℃の温度でバッチ焼鈍あるいは９００〜１１００℃の温度で連続焼鈍を施した後、酸洗等により脱スケールし、熱延製品とするのが好ましい。なお、必要に応じて、酸洗前にショットブラストによりスケール除去してもよい。
Preferred production conditions in the production method will be described.
In the steelmaking process for melting steel, it is preferable that the steel melted in a converter or an electric furnace is secondarily refined by a VOD method or the like, and the steel contains the above essential components and components added as necessary. . Although the molten steel can be made into a steel material by a known method, it is preferable to use a continuous casting method in terms of productivity and quality. Thereafter, the steel material is preferably heated to 1000 to 1250 ° C., and is hot rolled into a desired thickness by hot rolling. Of course, hot working can be performed in addition to the plate material. The hot-rolled sheet is then subjected to batch annealing at a temperature of 600 to 800 ° C. or continuous annealing at a temperature of 900 to 1100 ° C. as necessary, and then descaling by pickling or the like to obtain a hot-rolled product. preferable. If necessary, the scale may be removed by shot blasting before pickling.
さらに、上記熱延焼鈍板を、冷間圧延等の工程を経て冷延製品としてもよい。この場合の冷間圧延は、１回でもよいが、生産性や要求品質上の観点から中間焼鈍を挟む２回以上の冷間圧延としてもよい。１回または２回以上の冷間圧延の総圧下率は６０％以上が好ましく、より好ましくは７０％以上である。冷間圧延した鋼板は、その後、好ましくは９００〜１１５０℃、さらに好ましくは９５０〜１１２０℃の温度で連続焼鈍（仕上げ焼鈍）し、酸洗し、冷延製品とするのが好ましい。さらに用途によっては、仕上げ焼鈍後、スキンパス圧延等を施して、鋼板の形状や表面粗度、材質調整を行ってもよい。 Furthermore, the hot-rolled annealed plate may be a cold-rolled product through a process such as cold rolling. In this case, the cold rolling may be performed once, but may be performed twice or more with intermediate annealing in view of productivity and required quality. The total rolling reduction of one or more cold rollings is preferably 60% or more, more preferably 70% or more. The cold-rolled steel sheet is then preferably subjected to continuous annealing (finish annealing) at a temperature of 900 to 1150 ° C., more preferably 950 to 1120 ° C., pickling, and forming a cold-rolled product. Furthermore, depending on the application, after finish annealing, skin pass rolling or the like may be performed to adjust the shape, surface roughness, and material quality of the steel sheet.
上記のようにして得た熱延製品あるいは冷延製品は、その後、それぞれの用途に応じて、切断や曲げ加工、張出し加工、絞り加工等の加工を施して、自動車やオートバイの排気管、触媒外筒材、火力発電プラントの排気ダクトあるいは燃料電池関連部材、例えばセパレータ、インタコネクター、改質器等に成形される。これらの部材を溶接する方法は、特に限定されるものではなく、ＭＩＧ（Ｍｅｔａｌ Ｉｎｅｒｔ Ｇａｓ）、ＭＡＧ（Ｍｅｔａｌ Ａｃｔｉｖｅ Ｇａｓ）、ＴＩＧ（Ｔｕｎｇｓｔｅｎ Ｉｎｅｒｔ Ｇａｓ）等の通常のアーク溶接や、スポット溶接、シーム溶接等の抵抗溶接、および電縫溶接などの高周波抵抗溶接、高周波誘導溶接等を適用することができる。 The hot-rolled product or cold-rolled product obtained as described above is then subjected to processing such as cutting, bending, overhanging, drawing, etc. according to the respective application, and exhaust pipes and catalysts for automobiles and motorcycles. It is formed into an outer cylinder material, an exhaust duct of a thermal power plant, or a fuel cell-related member such as a separator, an interconnector, a reformer and the like. The method of welding these members is not particularly limited, and normal arc welding such as MIG (Metal Inert Gas), MAG (Metal Active Gas), TIG (Tungsten Inert Gas), spot welding, and seam welding. For example, resistance welding such as high frequency resistance welding such as electric resistance welding, high frequency induction welding, and the like can be applied.
以下、本発明を実施例により詳細に説明する。
表１に示したＮｏ．１〜４１の成分組成を有する鋼を真空溶解炉で溶製し、鋳造して３０ｋｇ鋼塊とし、鍛造して２分割した。その後、２分割した片方の鋼塊を１１７０℃に加熱し、次いで、熱間圧延して板厚５ｍｍの熱延板とし、１０００〜１１５０℃の範囲の温度で焼鈍後、酸洗し熱延焼鈍板とした。続いて、圧下率６０％の冷間圧延を行い、１０００〜１１５０℃の温度で仕上げ焼鈍を行った後、酸洗または研磨によりスケールを除去し、板厚が２ｍｍの冷延焼鈍板として、酸化試験に供した。なお、参考として、ＳＵＳ４４４（Ｎｏ．３０）についても、上記と同様にして冷延焼鈍板を作製し、酸化試験に供した。焼鈍温度については、上記温度範囲内で組織を確認しながら各鋼について温度を決定した。
Hereinafter, the present invention will be described in detail with reference to examples.
No. shown in Table 1. Steel having a component composition of 1 to 41 was melted in a vacuum melting furnace, cast into a 30 kg steel ingot, and forged into two parts. Thereafter, one of the two steel ingots was heated to 1170 ° C., then hot-rolled to form a hot-rolled sheet having a thickness of 5 mm, annealed at a temperature in the range of 1000 to 1150 ° C., and then pickled and hot-rolled annealed. A board was used. Subsequently, after performing cold rolling with a rolling reduction of 60% and finish annealing at a temperature of 1000 to 1150 ° C., the scale is removed by pickling or polishing, and a cold-rolled annealed plate having a thickness of 2 mm is oxidized. It used for the test. For reference, SUS444 (No. 30) was also subjected to an oxidation test by producing a cold-rolled annealed plate in the same manner as described above. About annealing temperature, temperature was determined about each steel, confirming a structure within the said temperature range.
＜大気中連続酸化試験＞
上記のようにして得た各種冷延焼鈍板から３０ｍｍ×２０ｍｍの試験片を切り出し、上部に４ｍｍφの穴をあけ、表面および端面を＃３２０のエメリー紙で研磨し、脱脂後、１１００℃に加熱保持した大気雰囲気の炉内に吊り下げて、２００時間保持した。試験後、試験片の質量を測定し、予め測定しておいた試験前の質量との差を求め、酸化増量（ｇ／ｍ２）を算出した。なお、試験は各２回実施し、その平均値で耐連続酸化性を評価した。なお、酸化増量には剥離したスケール分を含めて、以下のように評価した。
<Atmospheric continuous oxidation test>
Cut out a 30 mm x 20 mm test piece from the various cold-rolled annealed plates obtained as described above, make a hole of 4 mmφ on the top, polish the surface and end face with # 320 emery paper, degrease and heat to 1100 ° C It was suspended in the furnace of the hold | maintained atmospheric atmosphere, and was hold | maintained for 200 hours. After the test, the mass of the test piece was measured, the difference from the pre-test mass measured in advance was determined, and the increase in oxidation (g / m 2 ) was calculated. In addition, the test was implemented twice and the continuous oxidation resistance was evaluated by the average value. The increase in oxidation was evaluated as follows, including the peeled scale.
○：異常酸化もスケール剥離も発生しなかったもの
△：異常酸化は発生しないが、スケール剥離が生じたもの
×：異常酸化（酸化増量≧５０ｇ／ｍ２）が発生したもの
得られた結果を表１に示す。
○: Abnormal oxidation or scale peeling did not occur. Δ: Abnormal oxidation did not occur, but scale peeling occurred. ×: Abnormal oxidation (oxidation increase ≧ 50 g / m 2 ) occurred. Table 1 shows.
上記において２分割した３０ｋｇ鋼塊の残りの鋼塊を、１１７０℃に加熱後、熱間圧延して厚さ３５ｍｍ×幅１５０ｍｍのシートバーとした後、このシートバーを鍛造し、３０ｍｍ角の各棒とした。次いで、１０００〜１１５０℃の温度で焼鈍後、機械加工し、図１に示す形状、寸法の熱疲労試験片に加工し、下記の熱膨張係数の測定および熱疲労試験に供した。なお、参考として、ＳＵＳ４４４の成分組成を有する鋼についても、上記と同様にして試験片を作製し、熱膨張係数の測定および熱疲労試験に供した。 The remaining steel ingot of the 30 kg steel ingot divided into two in the above was heated to 1170 ° C. and hot-rolled into a sheet bar having a thickness of 35 mm × width of 150 mm, and then this sheet bar was forged, and each 30 mm square A stick. Next, after annealing at a temperature of 1000 to 1150 ° C., it was machined, processed into a thermal fatigue test piece having the shape and dimensions shown in FIG. 1, and subjected to the following measurement of thermal expansion coefficient and thermal fatigue test. For reference, a steel having a SUS444 component composition was prepared in the same manner as described above and subjected to measurement of the thermal expansion coefficient and thermal fatigue test.
＜熱膨張係数の測定＞
上記で作製した熱疲労試験片を用い、熱膨張係数の測定を行った。測定は、試験片に荷重を与えずに、２００℃から９５０℃の間で昇温、降温を３サイクル行い、変位が安定する３サイクル目の変位量を読み取って、熱膨張係数を算出し、以下のように評価した。
<Measurement of thermal expansion coefficient>
The thermal expansion coefficient was measured using the thermal fatigue test piece produced above. The measurement is performed by increasing and decreasing the temperature between 200 ° C. and 950 ° C. without applying a load to the test piece for 3 cycles, reading the displacement amount at the third cycle where the displacement is stabilized, and calculating the thermal expansion coefficient. Evaluation was performed as follows.
○：13.0×10-6/℃未満
×：13.0×10-6/℃以上
＜熱疲労試験＞
熱疲労試験は、図２に示すように、上記試験片を拘束率０．４５で拘束しながら、２００℃と９５０℃の間で昇温・降温を繰り返す条件で行った。この際の昇温速度および降温速度はそれぞれ７℃／ｓｅｃとし、２００℃での保持時間は１ｍｉｎ、９５０℃での保持時間は２ｍｉｎとした。なお、熱疲労寿命は、２００℃において検出された荷重を試験片均熱平行部（図１参照）の断面積で割って応力を算出し、初期のサイクル（試験が安定する５サイクル目）の値に対して７５％まで低下したサイクル数とし、以下のように評価した。
○: Less than 13.0 × 10 −6 / ° C ×: 13.0 × 10 −6 / ° C or more <Thermal fatigue test>
As shown in FIG. 2, the thermal fatigue test was performed under the condition that the temperature rise / fall was repeated between 200 ° C. and 950 ° C. while restraining the test piece at a restraint rate of 0.45. The temperature increase rate and temperature decrease rate were 7 ° C./sec, the holding time at 200 ° C. was 1 min, and the holding time at 950 ° C. was 2 min. The thermal fatigue life is calculated by dividing the load detected at 200 ° C. by the cross-sectional area of the test piece soaking parallel part (see FIG. 1), and calculating the stress. The number of cycles was reduced to 75% with respect to the value and evaluated as follows.
○：800サイクル以上
×：800サイクル未満
得られた結果を表１に示す。
○: 800 cycles or more ×: less than 800 cycles Table 1 shows the results obtained.
表１より、本発明例の鋼（Ｎｏ．１〜２９）は、いずれもＳＵＳ４４４（Ｎｏ．３０）より優れた耐酸化性および熱疲労特性を示している。これに対して、本発明の範囲を外れる比較例の鋼（Ｎｏ．３１〜４１）は、耐酸化性または熱疲労特性のいずれかもしくはその両方がＳＵＳ４４４と同等以下である。なお、実施例Ｎｏ．３３に関しては，Ａｌが適量添加されていないため、耐酸化性が不足しているのみならず、熱疲労特性も不十分であった。この原因としては、試験中に粗大な第二相が析出していたことが挙げられる。 From Table 1, the steels (Nos. 1 to 29) of the examples of the present invention all exhibit oxidation resistance and thermal fatigue characteristics superior to SUS444 (No. 30). On the other hand, the steel (No. 31-41) of the comparative example which deviates from the scope of the present invention has one or both of oxidation resistance and thermal fatigue characteristics equal to or less than SUS444. In addition, Example No. Regarding No. 33, since an appropriate amount of Al was not added, not only the oxidation resistance was insufficient, but also the thermal fatigue characteristics were insufficient. This is because a coarse second phase was precipitated during the test.
本発明のフェライト系ステンレス鋼は、自動車等の排気系部材用として好適であるだけでなく、同様の特性が要求される火力発電システムの排気系部材や固体酸化物タイプの燃料電池用部材としても好適に用いることができる。 The ferritic stainless steel of the present invention is not only suitable for exhaust system members such as automobiles, but also as exhaust system members for thermal power generation systems and solid oxide type fuel cell members that require similar characteristics. It can be used suitably.
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| CN106319373A (en) * | 2016-08-16 | 2017-01-11 | 盐城市科瑞达科技咨询服务有限公司 | Micro spherical ferritic stainless steel powder and preparation method thereof |
| WO2017056452A1 (en) * | 2015-09-29 | 2017-04-06 | Ｊｆｅスチール株式会社 | Ferrite-based stainless steel |
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| WO2020080104A1 (en) * | 2018-10-15 | 2020-04-23 | Ｊｆｅスチール株式会社 | Ferritic stainless steel |
| US10941461B2 (en) | 2016-03-31 | 2021-03-09 | Jfe Steel Corporation | Steel sheet, coated steel sheet, method for producing steel sheet, and method for producing coated steel sheet |
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| US11306369B2 (en) | 2017-02-24 | 2022-04-19 | Jfe Steel Corporation | High-strength stainless steel seamless pipe for oil country tubular goods, and method for producing same |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007314837A (en) * | 2006-05-25 | 2007-12-06 | Nisshin Steel Co Ltd | Age hardening type ferritic stainless steel sheet and age-treated steel material using the same |
| JP2008285693A (en) * | 2007-05-15 | 2008-11-27 | Nippon Steel & Sumikin Stainless Steel Corp | Ferritic stainless steel sheet having superior thermal fatigue resistance for component of automotive exhaust system |
| JP2012188748A (en) * | 2011-02-08 | 2012-10-04 | Nippon Steel & Sumikin Stainless Steel Corp | Hot rolled ferritic stainless steel sheet, method for producing the same, and method for producing ferritic stainless steel sheet |
| JP2013133482A (en) * | 2011-12-26 | 2013-07-08 | Jfe Steel Corp | Ferritic stainless steel excellent in corrosion resistance at welded part |
-
2014
- 2014-10-02 JP JP2014203587A patent/JP6075349B2/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007314837A (en) * | 2006-05-25 | 2007-12-06 | Nisshin Steel Co Ltd | Age hardening type ferritic stainless steel sheet and age-treated steel material using the same |
| JP2008285693A (en) * | 2007-05-15 | 2008-11-27 | Nippon Steel & Sumikin Stainless Steel Corp | Ferritic stainless steel sheet having superior thermal fatigue resistance for component of automotive exhaust system |
| JP2012188748A (en) * | 2011-02-08 | 2012-10-04 | Nippon Steel & Sumikin Stainless Steel Corp | Hot rolled ferritic stainless steel sheet, method for producing the same, and method for producing ferritic stainless steel sheet |
| JP2013133482A (en) * | 2011-12-26 | 2013-07-08 | Jfe Steel Corp | Ferritic stainless steel excellent in corrosion resistance at welded part |
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