JP5546911B2 - Ferritic stainless steel sheet with excellent heat resistance and workability - Google Patents
Ferritic stainless steel sheet with excellent heat resistance and workability Download PDFInfo
- Publication number
- JP5546911B2 JP5546911B2 JP2010055944A JP2010055944A JP5546911B2 JP 5546911 B2 JP5546911 B2 JP 5546911B2 JP 2010055944 A JP2010055944 A JP 2010055944A JP 2010055944 A JP2010055944 A JP 2010055944A JP 5546911 B2 JP5546911 B2 JP 5546911B2
- Authority
- JP
- Japan
- Prior art keywords
- workability
- stainless steel
- ferritic stainless
- heat resistance
- steel sheet
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 229910001220 stainless steel Inorganic materials 0.000 title claims description 28
- 229910000831 Steel Inorganic materials 0.000 claims description 47
- 239000010959 steel Substances 0.000 claims description 47
- 238000005096 rolling process Methods 0.000 claims description 24
- 238000001556 precipitation Methods 0.000 claims description 23
- 238000000137 annealing Methods 0.000 claims description 20
- 238000004519 manufacturing process Methods 0.000 claims description 12
- 229910052758 niobium Inorganic materials 0.000 claims description 11
- 229910001068 laves phase Inorganic materials 0.000 claims description 10
- 239000002131 composite material Substances 0.000 claims description 8
- 238000005098 hot rolling Methods 0.000 claims description 6
- 229910052802 copper Inorganic materials 0.000 claims description 5
- 229910052782 aluminium Inorganic materials 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims description 4
- 229910052720 vanadium Inorganic materials 0.000 claims description 4
- 229910052726 zirconium Inorganic materials 0.000 claims description 4
- 229910052804 chromium Inorganic materials 0.000 claims description 3
- 239000012535 impurity Substances 0.000 claims description 3
- 238000005554 pickling Methods 0.000 claims description 3
- 229910052718 tin Inorganic materials 0.000 claims description 3
- 229910052748 manganese Inorganic materials 0.000 claims description 2
- 239000002244 precipitate Substances 0.000 description 37
- 230000003647 oxidation Effects 0.000 description 24
- 238000007254 oxidation reaction Methods 0.000 description 24
- 238000005097 cold rolling Methods 0.000 description 15
- 238000000034 method Methods 0.000 description 15
- 238000005728 strengthening Methods 0.000 description 15
- 230000000694 effects Effects 0.000 description 14
- 230000006872 improvement Effects 0.000 description 10
- 230000007797 corrosion Effects 0.000 description 9
- 238000005260 corrosion Methods 0.000 description 9
- 230000035882 stress Effects 0.000 description 9
- 230000009467 reduction Effects 0.000 description 8
- 229910052750 molybdenum Inorganic materials 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 6
- 230000007423 decrease Effects 0.000 description 6
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 6
- 230000008569 process Effects 0.000 description 6
- 238000009864 tensile test Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 239000006104 solid solution Substances 0.000 description 5
- 230000002159 abnormal effect Effects 0.000 description 4
- 229910000963 austenitic stainless steel Inorganic materials 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 229910020010 Nb—Si Inorganic materials 0.000 description 3
- 230000009471 action Effects 0.000 description 3
- 230000032683 aging Effects 0.000 description 3
- 229910045601 alloy Inorganic materials 0.000 description 3
- 239000000956 alloy Substances 0.000 description 3
- 230000001965 increasing effect Effects 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 238000001953 recrystallisation Methods 0.000 description 3
- 238000007670 refining Methods 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- 238000012360 testing method Methods 0.000 description 3
- 230000015572 biosynthetic process Effects 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 238000004881 precipitation hardening Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 238000005204 segregation Methods 0.000 description 2
- 230000001629 suppression Effects 0.000 description 2
- 239000002344 surface layer Substances 0.000 description 2
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- 229910004353 Ti-Cu Inorganic materials 0.000 description 1
- 208000009205 Tinnitus Diseases 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 230000033228 biological regulation Effects 0.000 description 1
- 238000005266 casting Methods 0.000 description 1
- 238000004581 coalescence Methods 0.000 description 1
- 238000009749 continuous casting Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 230000006378 damage Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 239000011159 matrix material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000009628 steelmaking Methods 0.000 description 1
- 239000013585 weight reducing agent Substances 0.000 description 1
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/002—Heat treatment of ferrous alloys containing Cr
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium with copper
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of silicon
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/08—Other arrangements or adaptations of exhaust conduits
- F01N13/10—Other arrangements or adaptations of exhaust conduits of exhaust manifolds
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
- F01N13/00—Exhaust or silencing apparatus characterised by constructional features ; Exhaust or silencing apparatus, or parts thereof, having pertinent characteristics not provided for in, or of interest apart from, groups F01N1/00 - F01N5/00, F01N9/00, F01N11/00
- F01N13/16—Selection of particular materials
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Combustion & Propulsion (AREA)
- General Engineering & Computer Science (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Description
本発明は、特に高温強度や耐酸化性が必要な排気系部材などの使用に最適な耐熱性に優れたフェライト系ステンレス鋼板に関するものである。 The present invention relates to a ferritic stainless steel sheet having excellent heat resistance that is optimal for use in exhaust system members that require particularly high temperature strength and oxidation resistance.
自動車の排気マニホールド、フロントパイプおよびセンターパイプなどの排気系部材は、エンジンから排出される高温の排気ガスを通すため、排気部材を構成する材料には耐酸化性、高温強度、熱疲労特性など多様な特性が要求される。 Exhaust system members such as automobile exhaust manifolds, front pipes, and center pipes pass high-temperature exhaust gas exhausted from the engine, so the materials that make up the exhaust members have various characteristics such as oxidation resistance, high-temperature strength, and thermal fatigue characteristics. Is required.
従来、自動車排気部材には鋳鉄が使用されるのが一般的であったが、排ガス規制の強化、エンジン性能の向上、車体軽量化などの観点から、ステンレス鋼製の排気マニホールドが使用されるようになった。排ガス温度は車種やエンジン構造によって異なるが、600〜800℃程度が多く、このような温度域で長時間使用される環境において高い高温強度、耐酸化性を有する材料が要望されている。 Conventionally, cast iron is generally used for automobile exhaust members, but stainless steel exhaust manifolds are likely to be used from the viewpoints of strengthening exhaust gas regulations, improving engine performance, and reducing vehicle weight. Became. Although the exhaust gas temperature varies depending on the vehicle type and engine structure, it is often about 600 to 800 ° C., and a material having high high-temperature strength and oxidation resistance in an environment used for a long time in such a temperature range is desired.
ステンレス鋼の中でオーステナイト系ステンレス鋼は、耐熱性や加工性に優れているが、熱膨張係数が大きいために、排気マニホールドのように加熱・冷却を繰り返し受ける部材に適用した場合、熱疲労破壊が生じやすい。 Among stainless steels, austenitic stainless steel has excellent heat resistance and workability, but due to its large thermal expansion coefficient, thermal fatigue failure occurs when applied to a member that repeatedly receives heating and cooling, such as an exhaust manifold. Is likely to occur.
一方、フェライト系ステンレス鋼は、オーステナイト系ステンレス鋼に比べて熱膨張係数が小さいため、熱疲労特性や耐スケール剥離性に優れている。また、オーステナイト系ステンレス鋼に比べて、Niを含有しないため材料コストも安く、汎用的に使用されている。但し、フェライト系ステンレス鋼は、オーステナイト系ステンレス鋼に比べて、高温強度が低いために、高温強度を向上させる技術が開発されてきた。例えば、SUS430J1(Nb添加鋼)、Nb−Si添加鋼、SUS444(Nb−Mo添加鋼)があり、いずれもNb添加が前提となっている。これは、Nbによる固溶強化あるいは析出強化によって高温強度を高くするものであった。 On the other hand, since ferritic stainless steel has a smaller thermal expansion coefficient than austenitic stainless steel, it is excellent in thermal fatigue characteristics and scale peel resistance. Further, compared with austenitic stainless steel, it does not contain Ni, so the material cost is low and it is used for general purposes. However, since ferritic stainless steel has lower high-temperature strength than austenitic stainless steel, a technique for improving high-temperature strength has been developed. For example, there are SUS430J1 (Nb-added steel), Nb-Si-added steel, and SUS444 (Nb-Mo-added steel), all of which are premised on Nb addition. This increased the high-temperature strength by solid solution strengthening or precipitation strengthening with Nb.
ところで、Nbを添加すると再結晶温度が高温化するため、鋼板製造段階での焼鈍温度を高くする必要がある。また、Nb添加により硬質化するため、熱延後に熱延板焼鈍を施して軟質化した後に冷延する必要がある。更に、熱延工程で析出するNb析出物に起因して靭性が低下し、製造工程で割れや破断などのトラブルが生じる場合がある。この他、Nb添加鋼は製品板の硬質化、伸びの低下、深絞り性の指標となるr値が低い課題もある。これは、固溶Nbや析出Nbの存在により常温における硬質化や再結晶集合組織の発達が抑制されることで、排気部品を成形する際のプレス性、形状自由度を阻害するものである。このように、Nb添加鋼は鋼板の生産性、製造性ならびに加工性に課題がある。また、Nb添加により製造コストも上昇するため、Nb以外の添加元素によって高温特性を確保できればNb添加量を抑えることができ、低コストで加工性に優れた耐熱フェライト系ステンレス鋼板を提供することが可能になる。SUS444に添加されているMoは合金コストが高いため、部品コストが著しく上昇する課題も生じる。 By the way, when Nb is added, the recrystallization temperature rises, so it is necessary to increase the annealing temperature in the steel plate manufacturing stage. Moreover, since it hardens by addition of Nb, it is necessary to cold-roll after hot-rolled sheet annealing and softening after hot rolling. Further, the toughness is reduced due to Nb precipitates precipitated in the hot rolling process, and troubles such as cracks and breaks may occur in the manufacturing process. In addition, Nb-added steel also has a problem that the r value, which is an indicator of hardening of the product plate, reduction of elongation, and deep drawability, is low. This suppresses the hardenability at room temperature and the development of recrystallized texture due to the presence of solute Nb and precipitated Nb, thereby hindering the pressability and shape freedom when molding an exhaust part. Thus, Nb-added steel has problems in productivity, manufacturability and workability of the steel sheet. In addition, since the manufacturing cost increases due to the addition of Nb, the amount of Nb added can be suppressed if high temperature characteristics can be secured by an additive element other than Nb, and a heat-resistant ferritic stainless steel sheet excellent in workability at low cost can be provided. It becomes possible. Since Mo added to SUS444 has a high alloy cost, there is a problem in that the component cost is significantly increased.
NbやMo以外に高温強度向上に寄与する合金として、特許文献1〜6にCu添加に関する技術が開示されている。特許文献1は、Cu添加は低温靭性向上のために0.5%以下の添加が検討されており、耐熱性の観点からの添加ではない。特許文献2は、鋼の耐食性及び耐候性を高める作用を利用した技術であり、耐熱性の観点からの添加ではない。特許文献3〜6は、Cu析出物による析出硬化を利用して600℃あるいは700〜800℃の温度域における高温強度を向上させる技術が開示されている。しかしながら、これら従来技術はいずれもNbとの複合添加となっており、上記のような製造性に課題がある他、加工性やコストの面で課題があった。また、Cu添加による高温強度向上についての従来技術は、Cu析出物を利用したものであるが、Cu析出物は長時間高温に曝された場合、析出物の凝集・合体による粗大化が急速に生じるため、析出強化能が著しく低下してしまう問題がある。排気マニホールドのように、エンジンの起動・停止に伴う熱サイクルを受ける場合、長時間使用段階で著しく高温強度が低下して熱疲労破壊を起こす危険性が生じることになる。特にNbを多量に添加した成分系の場合、高温加熱時に粗大なLaves相と母相界面にCu析出物が析出するため、Cu析出物による析出強化能力が発現しない問題があった。特許文献6ではNb−Cu−B複合添加により微細なCuを析出させる技術が開示されているが、Laves相との複合析出は回避できないとともに、微量Mo添加が前提となっており加工性やコストに課題があった。このように、耐熱性の観点から高温強度を向上させるためにCuを微細に析出させる検討はあるが、従来技術ではCuの微細析出させるには至っておらず、加工性やコストの観点からも不十分なものであり、課題解決の検討がなされていない。一方、特許文献7〜9には、高温特性に優れたフェライト系ステンレス鋼として、Bを含有した鋼が開示されているが、いずれも加工性改善のためにB添加されており、耐熱性の観点からの添加ではない。 In addition to Nb and Mo, Patent Documents 1 to 6 disclose techniques relating to Cu addition as alloys that contribute to high temperature strength improvement. In Patent Document 1, addition of Cu of 0.5% or less has been studied for improving low temperature toughness, and Cu addition is not from the viewpoint of heat resistance. Patent Document 2 is a technique that utilizes the action of enhancing the corrosion resistance and weather resistance of steel, and is not an addition from the viewpoint of heat resistance. Patent Documents 3 to 6 disclose techniques for improving high-temperature strength in a temperature range of 600 ° C. or 700 to 800 ° C. using precipitation hardening by Cu precipitates. However, all of these conventional techniques are combined with Nb, and there are problems in manufacturability and cost as well as the above problems in manufacturability. Moreover, although the prior art about the high temperature strength improvement by Cu addition utilizes Cu precipitate, when Cu precipitate is exposed to high temperature for a long time, the coarsening by aggregation and coalescence of a precipitate rapidly Therefore, there is a problem that the precipitation strengthening ability is remarkably lowered. When the engine is subjected to a thermal cycle that accompanies start / stop of the engine, such as an exhaust manifold, there is a risk that thermal fatigue damage will occur due to a significant decrease in high-temperature strength in the long-term use stage. In particular, in the case of a component system in which a large amount of Nb is added, there is a problem that the precipitation strengthening ability due to the Cu precipitates is not exhibited because Cu precipitates are precipitated at the interface between the coarse Laves phase and the parent phase during high-temperature heating. Patent Document 6 discloses a technique for precipitating fine Cu by Nb—Cu—B composite addition. However, composite precipitation with the Laves phase cannot be avoided, and it is premised on the addition of a trace amount of Mo. There was a problem. As described above, there is a study for finely depositing Cu in order to improve the high temperature strength from the viewpoint of heat resistance, but the conventional technology has not led to the fine precipitation of Cu, and it is not possible from the viewpoint of workability and cost. It is enough, and the solution of the problem has not been studied. On the other hand, Patent Documents 7 to 9 disclose steel containing B as a ferritic stainless steel having excellent high-temperature characteristics, but all of them contain B for improving workability, and have high heat resistance. It is not an addition from the viewpoint.
本発明は、特に排気ガスの最高温度が600〜800℃となる熱環境下で使用され、耐熱性と加工性に優れたフェライト系ステンレス鋼を、安価に提供するものである。 The present invention provides a ferritic stainless steel that is used in a thermal environment where the maximum temperature of exhaust gas is 600 to 800 ° C. and excellent in heat resistance and workability at low cost.
本発明では、Nbを無添加とする鋼成分においてCu添加によってCu析出物を微細分散させることで高温特性を向上させた排気マニホールド用フェライト系ステンレス鋼板を安価に提供することを目的とし、Ti−Cu−B複合添加により析出物微細化を活用し、安価で耐熱性と加工性に優れた新しいフェライト系ステンレス鋼板を発明した。上記課題を解決するために、本発明者らはNbを多量に添加しない鋼における500℃〜800℃程度における高温強度の発現性並びに常温延性について詳細に調査した。そして、かかる目的を達成すべく種々の検討を重ねた結果、以下の知見を得た。この特徴として、Cu添加鋼の場合、上記温度域ではCu析出物が多量に析出することから、高温強度を向上させるためには析出物の形態を制御する方法が有効である。具体的には、TiとCuを複合添加し、更にB添加することでCu析出物が均一に微細析出し、析出強化活用とともに時効熱処理による強度低下を抑えることが可能となる。これは、排気部材のように繰り返し熱サイクルを受け、長期に使用される部品の耐久安定性に対して有効である。前述したようにNb添加鋼にCuを添加した場合もCu析出物が析出して強化に作用するが、同時にLaves相と呼ばれるFeとNbの析出物(Fe2Nb)が生成する。これは、Mo添加鋼においても同様にFeとMoの析出物(Fe2Mo)が生成する。この場合、粗大なLaves相と母相界面にCuが複合析出するため微細析出にならず、また温度条件によっては時間の経過とともに急激に粗大化してしまう。このような析出形態の場合は、強化能が低下してしまって十分な高温強度は得られず、耐久性が低くなる。そこで、本発明では、微細なCu析出物単独で析出強化の作用を得、かつ粗大化を抑制するために、Laves相とCuの複合析出が生じない微細析出技術によって、安価で耐熱性能を発揮する鋼材を提供することを可能とした。 In the present invention, an object of the present invention is to provide a low-cost ferritic stainless steel sheet for exhaust manifold, in which high temperature characteristics are improved by finely dispersing Cu precipitates by adding Cu in a steel component to which Nb is not added. A new ferritic stainless steel sheet was invented at low cost and excellent in heat resistance and workability by utilizing precipitate refinement by adding Cu-B composite. In order to solve the above-mentioned problems, the present inventors have investigated in detail the high temperature strength developability at about 500 ° C. to 800 ° C. and the normal temperature ductility in steel not containing a large amount of Nb. And as a result of repeating various examinations in order to achieve this purpose, the following knowledge was obtained. As a feature of this, in the case of Cu-added steel, a large amount of Cu precipitates precipitates in the above temperature range, and therefore a method of controlling the form of the precipitates is effective for improving the high temperature strength. Specifically, by adding Ti and Cu in combination, and further adding B, Cu precipitates are uniformly finely precipitated, and it is possible to suppress the strength reduction due to aging heat treatment as well as precipitation strengthening utilization. This is effective for durability stability of components that are subjected to repeated thermal cycles such as an exhaust member and are used for a long time. As described above, when Cu is added to the Nb-added steel, Cu precipitates precipitate and act on strengthening, but at the same time, Fe and Nb precipitates (Fe 2 Nb) called a Laves phase are generated. This is also the same in the Mo-added steel that precipitates of Fe and Mo (Fe 2 Mo) are generated. In this case, Cu precipitates at the interface between the coarse Laves phase and the matrix phase, so that fine precipitation does not occur, and depending on the temperature conditions, the precipitate rapidly becomes coarse over time. In the case of such a precipitation form, the strengthening ability is lowered and sufficient high-temperature strength cannot be obtained, resulting in low durability. Therefore, in the present invention, in order to obtain the effect of precipitation strengthening with fine Cu precipitates alone and to suppress coarsening, the fine precipitation technology that does not cause compound precipitation of the Laves phase and Cu does not cause low temperature and exhibits heat resistance performance. It was possible to provide steel materials to be used.
上記課題を解決する本発明の要旨は、
(1)質量%にて、C:0.02%以下、N:0.02%以下、Si:2%以下、Mn:2%以下、Cr:10〜20%、Cu:0.52〜3%、Ti:0.01〜0.5%、B:0.0002〜0.0030%を含有し、残部がFeおよび不可避的不純物からなり、平均r値≧1.3であることを特徴とする耐熱性と加工性に優れたフェライト系ステンレス鋼板。
(2)質量%にて、Nb:0.08〜0.2%、Mo:0.01〜0.3%、Al:2.5%以下、V:1%以下、Zr:1%以下、Sn:1%以下の1種以上を含有することを特徴とする(1)記載の耐熱性と加工性に優れたフェライト系ステンレス鋼板。
(3)600℃の耐力150MPa以上かつ800℃の耐力30MPa以上であることを特徴とする(1)または(2)記載の耐熱性と加工性に優れたフェライト系ステンレス鋼板。
(4)Laves相とCuとの複合析出が生じないことを特徴とする(1)〜(3)のいずれか記載の耐熱性と加工性に優れたフェライト系ステンレス鋼板。
(5)(1)または(2)記載の組成を有するフェライト系ステンレス鋼を熱延した後、熱延板焼鈍を省略して酸洗を施し、直径400mm以上の圧延ロールで冷延し、最終焼鈍を施すことを特徴とする耐熱性と加工性に優れたフェライト系ステンレス鋼板の製造方法。
The gist of the present invention for solving the above problems is as follows.
(1) In mass%, C: 0.02% or less, N: 0.02% or less, Si: 2% or less, Mn: 2% or less, Cr: 10-20%, Cu: 0.52-3 % Ti: 0.01 to 0.5% B: containing 0.0002 to 0.0030%, the balance Ri Do of Fe and unavoidable impurities, the average r value ≧ 1.3 der Rukoto Ferritic stainless steel sheet with excellent heat resistance and workability.
(2) In mass%, Nb: 0.08 to 0.2% , Mo: 0.01 to 0.3%, Al: 2.5% or less, V: 1% or less, Zr: 1% or less, Sn: Ferritic stainless steel sheet excellent in heat resistance and workability as described in (1) , containing one or more of 1% or less.
(3) The ferritic stainless steel sheet having excellent heat resistance and workability according to (1) or (2), wherein the proof stress is 600 MPa at 150 ° C or higher and 800 ° C at 30 MPa or higher.
(4) The ferritic stainless steel sheet excellent in heat resistance and workability according to any one of (1) to (3), wherein composite precipitation of the Laves phase and Cu does not occur.
( 5 ) After hot-rolling ferritic stainless steel having the composition described in (1) or (2), the hot-rolled sheet annealing is omitted and pickling is performed, and then cold rolling is performed with a rolling roll having a diameter of 400 mm or more. A method for producing a ferritic stainless steel sheet excellent in heat resistance and workability, characterized by annealing.
本発明によれば特に多量にNbを添加しなくても高温強度と加工性に優れたフェライト系ステンレス鋼板が得られ、特に自動車などの排気系部材に適用することにより、環境対策や部品の低コスト化などに大きな効果が得られる。 According to the present invention, a ferritic stainless steel sheet excellent in high-temperature strength and workability can be obtained without adding a particularly large amount of Nb. By applying it to exhaust system members such as automobiles in particular, environmental measures and low parts can be obtained. A great effect can be obtained for cost reduction.
ここで、下限の規定がないものについては、不可避的不純物レベルまで含むことを示す。 Here, for the case where the lower limit is not specified, it indicates that an inevitable impurity level is included.
以下に本発明の限定理由について説明する。 The reason for limitation of the present invention will be described below.
Cは、成形性と耐食性を劣化させ、高温強度の低下をもたらすため、その含有量は少ないほど良いため、0.02%以下とした。但し、過度の低減は精錬コストの増加に繋がるため、0.001〜0.009%が望ましい。 C deteriorates moldability and corrosion resistance and causes a decrease in high-temperature strength. Therefore, the smaller the content, the better. Therefore, the C content is set to 0.02% or less. However, excessive reduction leads to an increase in refining costs, so 0.001 to 0.009% is desirable.
NはCと同様、成形性と耐食性を劣化させ、高温強度の低下をもたらすため、その含有量は少ないほど良いため、0.02%以下とした。但し、過度の低減は精錬コストの増加に繋がるため、0.003〜0.015%が望ましい。 N, like C, deteriorates moldability and corrosion resistance and brings about a decrease in high-temperature strength. Therefore, the smaller the content, the better. Therefore, the N content is set to 0.02% or less. However, excessive reduction leads to an increase in refining costs, so 0.003 to 0.015% is desirable.
Siは、脱酸剤としても有用な元素であるとともに、高温強度と耐酸化性を改善する元素である。800℃程度までの高温強度は、Si量の増加とともに向上し、その効果は0.1%以上で発現する。しかしながら、過度な添加は常温延性を低下させるためその上限を2%とする。また、耐酸化性を考慮すると0.2〜1.0%が望ましい。 Si is an element that is also useful as a deoxidizer and is an element that improves high-temperature strength and oxidation resistance. The high-temperature strength up to about 800 ° C. increases with an increase in the amount of Si, and the effect appears at 0.1% or more. However, excessive addition reduces room temperature ductility, so the upper limit is made 2%. Further, considering oxidation resistance, 0.2 to 1.0% is desirable.
Mnは、脱酸剤として添加される元素であるとともに、中温域での高温強度上昇に寄与する。また、長時間使用中にMn系酸化物表層に形成し、スケール密着性や異常酸化抑制効果に寄与する。一方、2%超の過度な添加は、常温延性を低下させる他、MnSを形成して耐食性を低下させるため、上限を2%とした。更に、高温延性やスケール密着性を考慮すると、0.1〜1.0%が望ましい。 Mn is an element added as a deoxidizer and contributes to an increase in high-temperature strength in the middle temperature range. In addition, it forms on the Mn-based oxide surface layer during long-time use and contributes to the scale adhesion and the effect of suppressing abnormal oxidation. On the other hand, excessive addition of more than 2% lowers ordinary temperature ductility and also forms MnS to lower corrosion resistance, so the upper limit was made 2%. Furthermore, if considering high temperature ductility and scale adhesion, 0.1 to 1.0% is desirable.
Crは、本願発明において、耐酸化性や耐食性確保のために必須な元素である。10%未満では、その効果は発現せず、20%超では加工性の低下や靭性の劣化をもたらすため、10〜20%とした。更に、製造性や高温延性を考慮すると10〜18%が望ましい。 Cr is an essential element for ensuring oxidation resistance and corrosion resistance in the present invention. If it is less than 10%, the effect is not exhibited, and if it exceeds 20%, the workability is deteriorated and the toughness is deteriorated. Furthermore, considering the manufacturability and high temperature ductility, 10 to 18% is desirable.
Cuは、先述したように特に600〜800℃程度の中温度域における高温強度向上に有効な元素である。これは、該温度域におけるCu析出物の生成による析出強化が主な要因である。図1は、Cu添加鋼である鋼A(0.005%C−0.007%N−0.41%Si−0.45%Mn−10.5%Cr−1.25%Cu−0.15%Ti−0.0009%B)、鋼B(0.006%C−0.009%N−0.88%Si−0.31%Mn−13.9%Cr−1.42%Cu−0.11%Ti−0.0005%B)、鋼C(0.004%C−0.011%N−0.11%Si−0.13%Mn−17.5%Cr−1.36%Cu−0.19%Ti−0.0004%B)の高温耐力を示す。比較として汎用的に使用されているSUH409L(0.005%C−0.007%N−0.35%Si−0.50%Mn−10.5%Cr−0.15%Ti)とNb−Si鋼(0.006%C−0.009%N−0.90%Si−0.35%Mn−13.8%Cr−0.45%Nb)の結果も示す。ここで 高温引張試験はJISG0567に準拠して圧延方向に引張試験を実施し、0.2%耐力を測定した。これより、鋼A、鋼Bおよび鋼CともにNbが無添加であるにも関わらず、いずれの温度域においても既存鋼であるSUH409LやNb−Si鋼よりも高温強度が高いことがわかる。600℃程度の温度域では高強度であり、排気ガス温度が低い環境で使用される場合には特に有効であり、600℃未満の環境においても発明鋼は適用可能である。本発明では、汎用的に使用されている既存鋼であるNb−Si鋼の高温耐力を考慮し、600℃および800℃耐力がそれぞれ150MPa以上、および30MPa以上を高温強度の要求特性とした。このような効果は、Cu析出物が生成することによる析出硬化作用であり、0.4%以上の添加により発現する。また、本発明では、上記のようにLaves相との複合析出によるCu析出物の粗大化を抑制しているとともにTiやBとの複合添加によって微細にCu析出を生じる。一方、過度な添加は、常温延性および耐酸化性に支障が生じる。また、3%以上添加すると熱延工程での耳割れが顕著になり製造性に問題が生じるため上限を3%とした。製造性、スケール密着性および溶接性などを考慮すると、0.5〜2.5%が望ましい。 As described above, Cu is an element effective for improving the high-temperature strength particularly in the middle temperature range of about 600 to 800 ° C. This is mainly due to precipitation strengthening due to the formation of Cu precipitates in the temperature range. FIG. 1 shows steel A (0.005% C-0.007% N-0.41% Si-0.45% Mn-10.5% Cr-1.25% Cu-0. 15% Ti-0.0009% B), Steel B (0.006% C-0.009% N-0.88% Si-0.31% Mn-13.9% Cr-1.42% Cu- 0.11% Ti-0.0005% B), Steel C (0.004% C-0.011% N-0.11% Si-0.13% Mn-17.5% Cr-1.36% Cu-0.19% Ti-0.0004% B). For comparison, SUH409L (0.005% C-0.007% N-0.35% Si-0.50% Mn-10.5% Cr-0.15% Ti) and Nb- The results for Si steel (0.006% C-0.009% N-0.90% Si-0.35% Mn-13.8% Cr-0.45% Nb) are also shown. Here, the high temperature tensile test was carried out in the rolling direction in accordance with JISG0567, and the 0.2% proof stress was measured. From this, it can be seen that the steel A, steel B, and steel C have higher high-temperature strength than the existing steels SUH409L and Nb-Si steel in any temperature range, although Nb is not added. In the temperature range of about 600 ° C., the strength is high, and it is particularly effective when used in an environment where the exhaust gas temperature is low, and the invention steel can be applied even in an environment below 600 ° C. In the present invention, considering the high temperature proof stress of Nb-Si steel, which is an existing steel used for general purposes, 600 ° C. and 800 ° C. proof stress are 150 MPa or higher and 30 MPa or higher, respectively, as required characteristics of high temperature strength. Such an effect is a precipitation hardening action due to the formation of Cu precipitates, and is manifested by addition of 0.4% or more. Further, in the present invention, as described above, the coarsening of the Cu precipitate due to the composite precipitation with the Laves phase is suppressed, and fine Cu precipitation is caused by the composite addition with Ti and B. On the other hand, excessive addition causes trouble in normal temperature ductility and oxidation resistance. Further, when 3% or more is added, the ear cracking in the hot rolling process becomes prominent and a problem occurs in manufacturability, so the upper limit was made 3%. Considering manufacturability, scale adhesion and weldability, 0.5 to 2.5% is desirable.
Tiは、C,N,Sと結合して耐食性、耐粒界腐食性、常温延性や深絞り性を向上させる元素である。また、Cuとの複合添加において、適量添加することにより上記のようにCu析出物の均一析出をもたらし、高温強度及び熱疲労特性を向上させる。この作用は、結晶粒内のTiのクラスターあるいはTi系の微細な析出物がCu析出物の生成サイトになり、Cuが粒界に粗大に生成することを抑制するためと推察される。更に、冷間圧延後の再結晶焼鈍時に再結晶集合組織が発達し易くなるため、r値の向上に寄与し、プレス成形性を格段に向上させる。これらの効果は、0.01%以上から発現するが、0.5%超の添加により、固溶Ti量が増加して常温延性が低下する他、粗大なTi系析出物を形成し、穴拡げ加工時の割れの起点になり、プレス加工性を劣化させる。また、耐酸化性も劣化するため、Ti添加量は0.5%以下とした。更に、表面疵の発生や靭性を考慮すると0.05〜0.3%が望ましい。 Ti is an element that combines with C, N, and S to improve corrosion resistance, intergranular corrosion resistance, room temperature ductility and deep drawability. In addition, in the compound addition with Cu, addition of an appropriate amount brings about uniform precipitation of Cu precipitates as described above, and improves high-temperature strength and thermal fatigue characteristics. This effect is presumed to be because Ti clusters in the crystal grains or Ti-based fine precipitates become Cu precipitate generation sites, and Cu is not generated coarsely at the grain boundaries. Furthermore, since the recrystallized texture easily develops during recrystallization annealing after cold rolling, it contributes to the improvement of the r value and the press formability is remarkably improved. These effects are manifested from 0.01% or more, but addition of more than 0.5% increases the amount of solid solution Ti and lowers the room temperature ductility, forms coarse Ti-based precipitates, It becomes the starting point of cracks during expansion processing, and press workability deteriorates. Moreover, since oxidation resistance also deteriorates, Ti addition amount was made 0.5% or less. Furthermore, if considering the occurrence of surface flaws and toughness, 0.05 to 0.3% is desirable.
Bは、製品のプレス加工時の2次加工性を向上させる元素である。本発明ではTi―Cuと複合添加することで、Cu析出物が微細析出し、高温強度の向上にも寄与する。一般的にBは、高温域で(Fe,Cr)23(C,B)6やCr2Bを形成し易いが、Ti−Cu複合添加鋼においては、これらの析出物は析出せず、先述したCu析出物を微細析出させる効果があることが判明した。Cu析出物は通常析出初期において極めて微細に析出し強度向上効果が大きいが、時効熱処理により粗大化し、時効後の強度低下が大きい。しかしながら、B添加によりCu析出物の粗大化が抑制され、使用時の強度安定性が高くなる。B添加によるCu析出微細化および粗大化抑制効果の機構は明確ではないが、Bの粒界偏析によりCu析出物の粒界析出および粗大化を抑制し、粒内に微細析出させると推察される。これらの効果は、0.0002%以上で発現するが、過度な添加は硬質化や粒界腐食性と耐酸化性を劣化させる他、溶接割れが生じるため、0.0002〜0.0030%とした。更に、耐食性や製造コストを考慮すると、0.0003〜0.0015%が望ましい。 B is an element that improves the secondary workability during product press working. In the present invention, by adding Ti and Cu in combination, Cu precipitates are finely precipitated, which contributes to improvement of high temperature strength. In general, B tends to form (Fe, Cr) 23 (C, B) 6 or Cr 2 B in a high temperature range, but these precipitates do not precipitate in Ti—Cu composite added steel. It has been found that there is an effect of finely depositing the Cu precipitate. Cu precipitates are usually very finely precipitated at the initial stage of precipitation and have a large effect of improving the strength, but are coarsened by aging heat treatment, and the strength decrease after aging is large. However, the addition of B suppresses the coarsening of Cu precipitates and increases the strength stability during use. Although the mechanism of the Cu precipitation refinement and coarsening suppression effect due to the addition of B is not clear, it is presumed that the grain boundary segregation and coarsening of Cu precipitates are suppressed by B grain boundary segregation and fine precipitation is caused within the grains. . These effects are manifested at 0.0002% or more, but excessive addition deteriorates the hardness, intergranular corrosion and oxidation resistance, and also causes weld cracks, so 0.0002 to 0.0030%. did. Furthermore, if considering corrosion resistance and manufacturing cost, 0.0003 to 0.0015% is desirable.
以上の元素に加えて、必要に応じて、Nb、Mo、Al、V、Zrを添加しても良い。 In addition to the above elements, Nb, Mo, Al, V, and Zr may be added as necessary.
Nbは、高温強度や熱疲労特性を向上させるために必要に応じて添加すれば良いが、Laves相の生成が生じてCu析出による析出強化能力を抑制させてしまうため、多量の添加は望ましくない。また、加工性を阻害し、本発明が必須とする常温の破断伸びを確保できないので、上限を0.3%とする。更に、生産性や製造性の観点から、0.01〜0.2%が望ましい。 Nb may be added as necessary to improve the high temperature strength and thermal fatigue characteristics, but since the generation of the Laves phase occurs and the precipitation strengthening ability due to Cu precipitation is suppressed, addition of a large amount is not desirable. . Further, the workability is hindered and the elongation at break at room temperature required by the present invention cannot be secured, so the upper limit is made 0.3%. Furthermore, 0.01 to 0.2% is desirable from the viewpoint of productivity and manufacturability.
Moも高温強度や熱疲労特性をさらに向上させる元素である。しかしながら、多量に添加すると、Nbと同様にLaves相の析出が起こり好ましくない。さらには、常温延性も低下するため、微量添加が好ましく、0.01%以上0.3%以下が良い。さらに好ましくは、0.01%以上0.2%以下が良い。 Mo is an element that further improves high-temperature strength and thermal fatigue characteristics. However, if added in a large amount, the Laves phase precipitates in the same manner as Nb, which is not preferable. Furthermore, since room temperature ductility also falls, addition of trace amount is preferable and 0.01% or more and 0.3% or less are good. More preferably, it is 0.01% or more and 0.2% or less.
しかしながら、NbとMoを同時に添加する場合は、加工性の低下が懸念されるので、その合計量の上限は、0.2%未満が望ましい。 However, when Nb and Mo are added at the same time, there is a concern about deterioration of workability, so the upper limit of the total amount is preferably less than 0.2%.
Alは、脱酸元素として添加される他、耐酸化性を向上させるため必要に応じて添加する元素である。また、固溶強化元素として600〜700℃の強度向上に有用である。その作用は0.01%から安定して発現するが、過度の添加は硬質化して均一伸びを著しく低下させる他、靭性が著しく低下するため、上限を2.5%とした。更に、表面疵の発生や溶接性、製造性を考慮すると、0.01〜2.0%が望ましい。 In addition to being added as a deoxidizing element, Al is an element added as necessary to improve oxidation resistance. Moreover, it is useful for the strength improvement of 600-700 degreeC as a solid solution strengthening element. The action is stably manifested from 0.01%, but excessive addition hardens to significantly reduce uniform elongation, and toughness is significantly reduced, so the upper limit was made 2.5%. Furthermore, if generation of surface defects, weldability, and manufacturability are taken into consideration, 0.01 to 2.0% is desirable.
Vは、微細な炭窒化物を形成し、析出強化作用が生じて高温強度向上に寄与するため必要に応じて添加する元素である。この効果は0.01%以上の添加で安定して発現するが、1%超添加すると析出物が粗大化して高温強度が低下し、熱疲労寿命は低下してしまうため、上限を1%とした。更に、製造コストや製造性を考慮すると、0.08〜0.5%が望ましい。 V is an element which is added as necessary because it forms fine carbonitrides and a precipitation strengthening effect is generated, contributing to the improvement of high temperature strength. This effect is stably exhibited by addition of 0.01% or more. However, if added over 1%, the precipitate becomes coarse and the high-temperature strength decreases and the thermal fatigue life decreases, so the upper limit is set to 1%. did. Furthermore, if considering the manufacturing cost and manufacturability, 0.08 to 0.5% is desirable.
ZrはTiやNb同様に炭窒化物形成元素であり、固溶Ti,Nb量の増加による高温強度向上、耐酸化性の向上に寄与し、0.2%以上の添加により安定して効果を発揮するため必要に応じて添加する元素である。しかしながら、1%超の添加により製造性の劣化が著しいため、0.2〜1%とした。更に、コストや表面品位を考慮すると、0.2〜0.6%が望ましい。 Zr is a carbonitride-forming element like Ti and Nb, contributes to the improvement of high temperature strength and oxidation resistance by increasing the amount of solid solution Ti and Nb, and is stable by adding 0.2% or more. It is an element that is added as necessary to exert its effect. However, since the deterioration of manufacturability due to the addition of more than 1% is remarkable, the content is set to 0.2 to 1%. Furthermore, if considering cost and surface quality, 0.2 to 0.6% is desirable.
Snは、原子半径が大きく固溶強化に有効な元素であり、常温の機械的特性を大きく劣化させないため必要に応じて添加する元素である。高温強度への寄与は0.1%以上で安定して発現するが、1%以上添加すると製造性や溶接性が著しく劣化するため、0.1〜1%が好ましい。更に、耐酸化性等を考慮すると、0.2〜0.5%が望ましい。 Sn is an element having a large atomic radius and effective for solid solution strengthening, and is an element that is added as necessary because it does not significantly deteriorate the mechanical properties at room temperature. The contribution to the high-temperature strength is stably manifested at 0.1% or more, but if added at 1% or more, manufacturability and weldability are remarkably deteriorated, so 0.1 to 1% is preferable. Furthermore, if considering oxidation resistance and the like, 0.2 to 0.5% is desirable.
本発明は、NbおよびMoを無添加ないしは低濃度含有量とし、かつ、高温強度を確保し得た。その結果、常温伸びの向上を実現することができた。 In the present invention, Nb and Mo were not added or contained at a low concentration, and high temperature strength could be secured. As a result, improvement in room temperature elongation could be realized.
次に製造方法について説明する。本発明の鋼板の製造方法は、製鋼−熱間圧延−酸洗−冷間圧延−焼鈍・酸洗の各工程よりなる。製鋼においては、前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を、転炉溶製し続いて2次精錬を行う方法が好適である。溶製した溶鋼は、公知の鋳造方法(連続鋳造)に従ってスラブとする。スラブは、所定の温度に加熱され、所定の板厚に連続圧延で熱間圧延される。冷間圧延条件について、ステンレス鋼板の冷間圧延は、通常ロール径が60〜100mm程度のゼンジミア圧延機でリバース圧延されるか、ロール径が400mm以上のタンデム式圧延機で一方向圧延されるかである。いずれも、複数パスで圧延される。 Next, a manufacturing method will be described. The manufacturing method of the steel plate of this invention consists of each process of steelmaking-hot rolling-pickling-cold rolling-annealing and pickling. In steelmaking, a method in which the steel containing the above essential components and components added as necessary is subjected to furnace melting followed by secondary refining. The molten steel is made into a slab according to a known casting method (continuous casting). The slab is heated to a predetermined temperature and hot-rolled to a predetermined plate thickness by continuous rolling. Regarding cold rolling conditions, is cold rolling of stainless steel sheet usually reverse rolled with a Sendzimir mill with a roll diameter of about 60 to 100 mm or unidirectionally rolled with a tandem rolling mill with a roll diameter of 400 mm or more? It is. Both are rolled in multiple passes.
本発明では、加工性の指標であるr値を高くするために、ロール径が400mm以上のタンデム式圧延機で冷間圧延を施す方が好ましい。ロール径が100mm以下と小さい場合、冷間圧延時に表層近傍にせん断歪みが多く導入され、次工程の再結晶焼鈍時に<111>や<554>結晶方位発達が抑制され、r値の向上が困難となる。大径ロールで冷間圧延することによって、せん断歪みの抑制によって上記結晶方位が顕著に発達し、r値向上に寄与する。また、タンデム式圧延は一方向圧延であり、ゼンジミア圧延に比べて圧延パス数が少ないため、生産性においても優れる。尚、冷間圧延工程における圧下率が低いと焼鈍後に再結晶組織が得られなかったり、過度に粗粒化して機械的性質を劣化させるため、冷間圧延工程の圧下率は30%以上が望ましい。 In the present invention, in order to increase the r value which is an index of workability, it is preferable to perform cold rolling with a tandem rolling mill having a roll diameter of 400 mm or more. When the roll diameter is as small as 100 mm or less, a large amount of shear strain is introduced in the vicinity of the surface layer during cold rolling, and <111> and <554> crystal orientation development is suppressed during recrystallization annealing in the next process, making it difficult to improve the r value. It becomes. By cold rolling with a large-diameter roll, the crystal orientation is remarkably developed due to suppression of shear strain, which contributes to improvement of the r value. Tandem rolling is unidirectional rolling, and has fewer rolling passes than Sendzimir rolling, and is excellent in productivity. In addition, if the rolling reduction in the cold rolling process is low, a recrystallized structure cannot be obtained after annealing or excessively coarsened to deteriorate the mechanical properties. Therefore, the rolling reduction in the cold rolling process is preferably 30% or more. .
また、フェライト系ステンレス鋼板の製造において通常実施される熱延板焼鈍を施しても良いが、本発明では熱延板の焼鈍は施さない方が生産性向上の観点から好ましい。通常のNb添加鋼は熱延板が硬質であるため、冷延する前に焼鈍が施されるが、本発明鋼はNbを添加しないか、少量添加のため熱延板の焼鈍を省略することが可能となり、製造コストの低減をもたらす。また、熱延板の焼鈍を省略することにより、冷延・焼鈍後の集合組織が発達し、r値向上や異方性低減によるプレス成形性の向上にもつながる。 Moreover, although hot-rolled sheet annealing normally performed in manufacture of a ferritic stainless steel plate may be performed, in the present invention, it is preferable from the viewpoint of improving productivity that the hot-rolled sheet is not annealed. Since normal Nb-added steel has a hot-rolled sheet that is hard, it is annealed before cold rolling, but the steel of the present invention does not add Nb or omits the annealing of the hot-rolled sheet due to the addition of a small amount. This can reduce the manufacturing cost. Further, by omitting the annealing of the hot-rolled sheet, a texture after cold rolling / annealing develops, which leads to an improvement in press formability by improving r value and reducing anisotropy.
他工程の製造方法については特に規定しないが、熱延条件、熱延板厚、冷延板焼鈍温度、雰囲気などは適宜選択すれば良い。また、冷延・焼鈍後に調質圧延やテンションレベラーを付与しても構わない。更に、製品板厚についても、要求部材厚に応じて選択すれば良い。なお、本発明はNb無添加ないしNb含有量が低いので、冷間圧延後の焼鈍温度を850〜970℃と低い温度とすることができる。これにより、焼鈍温度が970℃を超える場合に比較し高温耐力を向上することができる。 The manufacturing method in other steps is not particularly defined, but hot rolling conditions, hot rolled sheet thickness, cold rolled sheet annealing temperature, atmosphere, and the like may be appropriately selected. Further, temper rolling or tension leveler may be applied after cold rolling and annealing. Further, the product plate thickness may be selected according to the required member thickness. In addition, since this invention does not add Nb thru | or low Nb content, the annealing temperature after cold rolling can be made into 850-970 degreeC low temperature. Thereby, high temperature proof stress can be improved compared with the case where annealing temperature exceeds 970 degreeC.
表1、2に示す成分組成の鋼を溶製してスラブに鋳造し、スラブを熱間圧延して5mm厚の熱延コイルとした。その後、熱延コイルを焼鈍せずに酸洗し、2mm厚まで冷間圧延し、焼鈍・酸洗を施して製品板とした。ここで、冷間圧延において、大径ロール(直径450mm)を有する圧延機で一方向の多パス圧延を行い、比較として小径ロール(直径100mm)を有する圧延機でリバース式の多パス圧延を行った。冷延板の焼鈍温度は、結晶粒度番号を6〜8程度にするために、850〜970℃とした。Nb含有量が本発明の上限を外れる比較例については、冷延板の焼鈍温度を1000〜1050℃とした。表中のNo.1〜17、37は本発明鋼、No.18〜36は比較鋼で、No.18はSUH409L、No.19と20はNb−Si添加鋼として使用実績がある鋼である。
Steels having the composition shown in Tables 1 and 2 were melted and cast into a slab, and the slab was hot-rolled to form a hot-rolled coil having a thickness of 5 mm. Thereafter, the hot rolled coil was pickled without being annealed, cold-rolled to a thickness of 2 mm, annealed and pickled to obtain a product plate. Here, in cold rolling, unidirectional multi-pass rolling is performed with a rolling mill having a large-diameter roll (diameter 450 mm), and reverse multi-pass rolling is performed with a rolling mill having a small-diameter roll (
このようにして得られた製品板から、高温引張試験片を採取し、600℃および800℃で引張試験を実施し、0.2%耐力を測定した(JISG0567に準拠)。600℃耐力が150MPa以上、800℃耐力が30MPa以上を合格とした。また、耐酸化性の試験として、大気中900℃で200時間の連続酸化試験を行い、異常酸化の発生有無を評価した(JISZ2281に準拠)。異常酸化なしを合格とした。 From the product plate thus obtained, a high-temperature tensile test piece was collected, a tensile test was performed at 600 ° C. and 800 ° C., and a 0.2% proof stress was measured (based on JISG0567). A 600 ° C. proof stress of 150 MPa or higher and an 800 ° C. proof strength of 30 MPa or higher were accepted. Further, as an oxidation resistance test, a continuous oxidation test was performed at 900 ° C. in the atmosphere for 200 hours to evaluate whether or not abnormal oxidation occurred (based on JISZ2281). No abnormal oxidation was accepted.
常温の加工性として、JIS13号B試験片を作製して圧延方向と平行方向の引張試験を行い、破断伸びを測定した。常温での破断伸びは35%以上あれば、複雑な部品への加工が可能となるため、破断伸び35%以上を合格とした。 As normal temperature workability, a JIS No. 13 B test piece was prepared and subjected to a tensile test in the direction parallel to the rolling direction, and the elongation at break was measured. If the elongation at break at room temperature is 35% or more, it becomes possible to process a complicated part.
r値の評価は、JIS13号B引張試験片を採取して圧延方向、圧延方向と45°方向、圧延方向と90°方向に15%歪みを付与した後に(1)式および(2)式を用いて平均r値を算出した。
r=ln(W0/W)/ln(t0/t) (1)
ここで、W0は引張前の板幅、Wは引張後の板幅、t0は引張前の板厚、tは引張後の板厚である。
平均r値=(r0+2r45+r90)/4 (2)
ここで、r0は圧延方向のr値、r45は圧延方向と45°方向のr値、r90は圧延方向と直角方向のr値である。ここで、平均r値が1.3以上あれば、複雑な部品への加工が可能となるため、平均r値1.3以上を有することが望ましい。
The evaluation of the r value was performed by taking the JIS No. 13 B tensile test piece and applying 15% strain in the rolling direction, the rolling direction and 45 ° direction, and the rolling direction and 90 ° direction. The average r value was calculated.
r = ln (W 0 / W) / ln (t 0 / t) (1)
Here, W 0 is the plate width before tension, W is the plate width after tension, t 0 is the plate thickness before tension, and t is the plate thickness after tension.
Average r value = (r 0 + 2r 45 + r 90 ) / 4 (2)
Here, r 0 is the r value in the rolling direction, r 45 is the r value in the rolling direction and the 45 ° direction, and r 90 is the r value in the direction perpendicular to the rolling direction. Here, if the average r value is 1.3 or more, it becomes possible to process a complex part. Therefore, it is desirable to have an average r value of 1.3 or more.
表1、2において、成分は質量%を意味する。また本発明範囲から外れる数値にアンダーラインを付している。表1、2から明らかなように、No.1〜17の本発明で規定する成分組成を有する鋼を上記のような通常の方法にて製造した場合、比較例に比べて600℃、800℃における高温耐力が高く、900℃において異常酸化がなく耐酸化性にも優れていることがわかる。 In Tables 1 and 2, the component means mass%. In addition, numerical values outside the scope of the present invention are underlined. As is clear from Tables 1 and 2, No. When steel having the component composition specified in the present invention of 1 to 17 is produced by the ordinary method as described above, the high temperature proof stress at 600 ° C. and 800 ° C. is higher than that of the comparative example, and abnormal oxidation occurs at 900 ° C. It turns out that it is excellent also in oxidation resistance.
また、常温での機械的性質において破断延性が35%以上と高く、比較鋼に比べて加工性に優れていることがわかる。 In addition, it can be seen that the mechanical properties at room temperature have a high ductility at break of 35% or more, which is superior to the comparative steel in workability.
比較鋼のNo.18,19,20は既存鋼であるが、高温強度が要求値よりも低く、Nbを過剰に添加した比較鋼No.19,20はr値も低い。No.21と22は、それぞれCとNが上限外れで、高温強度、耐酸化性、加工性に劣る。No.23は、Siが過剰に添加されており、加工性に劣る。No.24は、Mnが過剰に添加されており、耐酸化性と加工性に劣る。No.25は、Cr量が少ないため高温強度が低いとともに耐酸化性も劣る。No.26は、Cu添加量が少ないため600℃と800℃の0.2%耐力が低い。No.27は、Tiが上限外れで耐酸化性と加工性が劣る。No.28は、Ti量が下限外れでNbを過剰に添加したため、延性が低い。No.29は、Nbが過剰に添加されているため、延性やr値が低い。No.30は、Bが上限外れのため耐酸化性や加工性が低い。No.31はB添加量が0.0001%と下限外れであるため、800℃においてCu析出物が粗大化して強化能力が低下し、耐力が低い。No.32〜36は、Mo、Al、V、ZrおよびSnが上限外れのため常温延性が低く、部品加工に支障をきたす。 No. of comparative steel. Nos. 18, 19, and 20 are existing steels, but the high-temperature strength is lower than the required value, and comparative steel No. 1 in which Nb is excessively added. 19 and 20 also have a low r value. No. 21 and 22 are inferior in high temperature strength, oxidation resistance, and workability because C and N are outside the upper limits. No. In No. 23, Si is excessively added and the processability is poor. No. In No. 24, Mn is excessively added, which is inferior in oxidation resistance and workability. No. No. 25 has low Cr content and low oxidation resistance as well as low Cr content. No. No. 26 has a low 0.2% yield strength at 600 ° C. and 800 ° C. due to a small amount of Cu added. No. In No. 27, Ti is off the upper limit and the oxidation resistance and workability are poor. No. No. 28 has low ductility because Nb was excessively added with the Ti amount off the lower limit. No. No. 29 has low ductility and r value because Nb is added excessively. No. No. 30 has low oxidation resistance and workability because B is off the upper limit. No. No. 31 has a B addition amount of 0.0001%, which is outside the lower limit, so that the Cu precipitate is coarsened at 800 ° C., the strengthening ability is lowered, and the yield strength is low. No. In Nos. 32 to 36, Mo, Al, V, Zr, and Sn are off the upper limit, so that the room temperature ductility is low, which hinders part processing.
本発明例のうち、冷間圧延に大径ロールを用いたNo.1〜17は、平均r値も1.3以上と良好な値を示した。本発明例のNo.37鋼は、高温耐力と常温での破断延性は良好であるが、冷延ロール径が小さいため、r値が好ましい範囲よりは低い値となった。 Among the examples of the present invention, No. 1 using a large diameter roll for cold rolling. 1-17 showed the average r value also as a favorable value of 1.3 or more. No. of the example of the present invention. Steel No. 37 has good high-temperature proof stress and break ductility at normal temperature, but its r-value is lower than the preferred range because the cold-rolled roll diameter is small.
以上の説明から明らかなように、本発明によればNbやMoのような高価な合金元素を多量に添加せずとも高温特性と加工性に優れたステンレス鋼板を提供することができ、特に排気部材に適用することにより、部品コストの低減や軽量化による環境対策など社会的寄与は格段に大きい。 As is apparent from the above description, according to the present invention, a stainless steel plate excellent in high temperature characteristics and workability can be provided without adding a large amount of expensive alloy elements such as Nb and Mo. By applying to materials, social contributions such as reduction of parts cost and environmental measures by weight reduction are much greater.
Claims (5)
Priority Applications (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2010055944A JP5546911B2 (en) | 2009-03-24 | 2010-03-12 | Ferritic stainless steel sheet with excellent heat resistance and workability |
KR1020117022445A KR20110120352A (en) | 2009-03-24 | 2010-03-23 | Ferritic stainless steel plate having excellent heat resistance and excellent workability |
KR1020147025032A KR20140117686A (en) | 2009-03-24 | 2010-03-23 | Ferritic stainless steel plate having excellent heat resistance and excellent workability |
PCT/JP2010/055488 WO2010110466A1 (en) | 2009-03-24 | 2010-03-23 | Ferritic stainless steel plate having excellent heat resistance and excellent workability |
EP10756261.3A EP2412837B8 (en) | 2009-03-24 | 2010-03-23 | Ferritic stainless steel plate having excellent heat resistance and excellent workability |
US13/259,330 US20120014830A1 (en) | 2009-03-24 | 2010-03-23 | Ferritic stainless steel excellent in heat resistance and workability sheet |
CN201080013394.4A CN102361999B (en) | 2009-03-24 | 2010-03-23 | Ferritic stainless steel plate having excellent heat resistance and excellent workability |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2009072320 | 2009-03-24 | ||
JP2009072320 | 2009-03-24 | ||
JP2010055944A JP5546911B2 (en) | 2009-03-24 | 2010-03-12 | Ferritic stainless steel sheet with excellent heat resistance and workability |
Publications (2)
Publication Number | Publication Date |
---|---|
JP2010248620A JP2010248620A (en) | 2010-11-04 |
JP5546911B2 true JP5546911B2 (en) | 2014-07-09 |
Family
ID=42781156
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP2010055944A Active JP5546911B2 (en) | 2009-03-24 | 2010-03-12 | Ferritic stainless steel sheet with excellent heat resistance and workability |
Country Status (6)
Country | Link |
---|---|
US (1) | US20120014830A1 (en) |
EP (1) | EP2412837B8 (en) |
JP (1) | JP5546911B2 (en) |
KR (2) | KR20140117686A (en) |
CN (1) | CN102361999B (en) |
WO (1) | WO2010110466A1 (en) |
Families Citing this family (19)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5709571B2 (en) * | 2011-02-17 | 2015-04-30 | 新日鐵住金ステンレス株式会社 | High purity ferritic stainless steel sheet excellent in oxidation resistance and high temperature strength and method for producing the same |
JP5709570B2 (en) * | 2011-02-17 | 2015-04-30 | 新日鐵住金ステンレス株式会社 | High purity ferritic stainless steel sheet excellent in oxidation resistance and high temperature strength and method for producing the same |
JP5304935B2 (en) | 2011-10-14 | 2013-10-02 | Jfeスチール株式会社 | Ferritic stainless steel |
JP5234214B2 (en) | 2011-10-14 | 2013-07-10 | Jfeスチール株式会社 | Ferritic stainless steel |
KR101454505B1 (en) | 2011-11-17 | 2014-10-28 | 주식회사 만도 | Rack Assist Type Electric Power Steering Apparatus |
JP6071608B2 (en) | 2012-03-09 | 2017-02-01 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel plate with excellent oxidation resistance |
EP2902523B1 (en) | 2012-09-25 | 2018-09-05 | JFE Steel Corporation | Ferritic stainless steel |
CN103060697B (en) * | 2012-12-25 | 2014-12-24 | 钢铁研究总院 | Medium Cr ferrite stainless steel with ultra low content of C and N and manufacturing method thereof |
US10450623B2 (en) | 2013-03-06 | 2019-10-22 | Nippon Steel & Sumikin Stainless Steel Corporation | Ferritic stainless steel sheet having excellent heat resistance |
EP2980251B1 (en) | 2013-03-27 | 2017-12-13 | Nippon Steel & Sumikin Stainless Steel Corporation | Hot-rolled ferritic stainless-steel plate, process for producing same, and steel strip |
US10415126B2 (en) | 2014-05-14 | 2019-09-17 | Jfe Steel Corporation | Ferritic stainless steel |
CA2964055C (en) * | 2014-10-31 | 2020-06-30 | Nippon Steel & Sumikin Stainless Steel Corporation | Ferrite-based stainless steel plate, steel pipe, and production method therefor |
JP6300841B2 (en) * | 2016-01-28 | 2018-03-28 | 新日鐵住金ステンレス株式会社 | Al-containing ferritic stainless steel with excellent high-temperature strength |
JP6261640B2 (en) * | 2016-03-30 | 2018-01-17 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel sheet and steel pipe for exhaust parts with excellent workability and manufacturing method thereof |
JP6628682B2 (en) * | 2016-05-06 | 2020-01-15 | 日鉄ステンレス株式会社 | High-strength stainless steel sheet excellent in workability and method for producing the same |
JP6765287B2 (en) * | 2016-11-17 | 2020-10-07 | 日鉄ステンレス株式会社 | Ferritic stainless steel, its manufacturing method, and fuel cell components |
US20190382874A1 (en) * | 2017-01-19 | 2019-12-19 | Nisshin Steel Stainless Steel Corporation | Ferritic stainless steel and ferritic stainless steel for automobile exhaust gas passage member |
JP6858056B2 (en) * | 2017-03-30 | 2021-04-14 | 日鉄ステンレス株式会社 | Low specific gravity ferritic stainless steel sheet and its manufacturing method |
TWI801538B (en) * | 2018-03-27 | 2023-05-11 | 日商日鐵不銹鋼股份有限公司 | Ferritic stainless steel, method for producing the same, ferritic stainless steel sheet, method for producing the same, and members for fuel cell |
Family Cites Families (21)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3429023B2 (en) * | 1993-04-23 | 2003-07-22 | 東北特殊鋼株式会社 | Electromagnetic stainless steel sheet with excellent soft magnetic properties and press formability |
JP3477957B2 (en) * | 1995-11-24 | 2003-12-10 | Jfeスチール株式会社 | Ferritic stainless steel with excellent corrosion resistance under high temperature oxidation environment of 200-400 ° C |
JPH09279312A (en) | 1996-04-18 | 1997-10-28 | Nippon Steel Corp | Ferritic stainless steel excellent in high temperature characteristic, corrosion resistance, and workability |
JP3536567B2 (en) | 1997-01-24 | 2004-06-14 | Jfeスチール株式会社 | Ferritic stainless steel for engine exhaust components with excellent heat resistance, workability and muffler corrosion resistance |
JP2000169943A (en) | 1998-12-04 | 2000-06-20 | Nippon Steel Corp | Ferritic stainless steel excellent in high temperature strength and its production |
JP3468156B2 (en) | 1999-04-13 | 2003-11-17 | 住友金属工業株式会社 | Ferritic stainless steel for automotive exhaust system parts |
JP3397167B2 (en) | 1999-04-16 | 2003-04-14 | 住友金属工業株式会社 | Ferritic stainless steel for automotive exhaust system parts |
JP3446667B2 (en) | 1999-07-07 | 2003-09-16 | 住友金属工業株式会社 | Ferritic stainless steel, ferritic stainless steel ingot excellent in workability and toughness, and method for producing the same |
TW480288B (en) * | 1999-12-03 | 2002-03-21 | Kawasaki Steel Co | Ferritic stainless steel plate and method |
JP3474829B2 (en) * | 2000-05-02 | 2003-12-08 | 新日本製鐵株式会社 | Heat-resistant ferritic stainless steel for catalyst support with excellent weldability and workability |
JP4968987B2 (en) * | 2001-05-16 | 2012-07-04 | 新日鐵住金ステンレス株式会社 | Stainless steel for CRT support frame with excellent machinability and medium temperature strength |
DE60204323T2 (en) | 2001-07-05 | 2006-01-26 | Nisshin Steel Co., Ltd. | FERRITIC STAINLESS STEEL FOR AN ELEMENT OF AN EXHAUST GAS PASSAGE |
JP4400058B2 (en) * | 2003-02-13 | 2010-01-20 | Jfeスチール株式会社 | Ferritic stainless steel welded pipe with excellent spinning processability |
US20060225820A1 (en) * | 2005-03-29 | 2006-10-12 | Junichi Hamada | Ferritic stainless steel sheet excellent in formability and method for production thereof |
JP2006037176A (en) | 2004-07-28 | 2006-02-09 | Nisshin Steel Co Ltd | Ferritic stainless steel for exhaust manifold |
DK1637785T3 (en) * | 2004-09-15 | 2010-08-16 | Sumitomo Metal Ind | Steel pipes with excellent exfoliation resistance to peel on the inner surface |
JP4468137B2 (en) * | 2004-10-20 | 2010-05-26 | 日新製鋼株式会社 | Ferritic stainless steel material and automotive exhaust gas path member with excellent thermal fatigue characteristics |
JP4624808B2 (en) * | 2005-01-12 | 2011-02-02 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel sheet with excellent workability and method for producing the same |
JP4614787B2 (en) * | 2005-02-18 | 2011-01-19 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel sheet excellent in workability and heat resistance and method for producing the same |
JP4948998B2 (en) * | 2006-12-07 | 2012-06-06 | 日新製鋼株式会社 | Ferritic stainless steel and welded steel pipe for automotive exhaust gas flow path members |
JP5297630B2 (en) | 2007-02-26 | 2013-09-25 | 新日鐵住金ステンレス株式会社 | Ferritic stainless steel plate with excellent heat resistance |
-
2010
- 2010-03-12 JP JP2010055944A patent/JP5546911B2/en active Active
- 2010-03-23 CN CN201080013394.4A patent/CN102361999B/en active Active
- 2010-03-23 EP EP10756261.3A patent/EP2412837B8/en active Active
- 2010-03-23 US US13/259,330 patent/US20120014830A1/en not_active Abandoned
- 2010-03-23 KR KR1020147025032A patent/KR20140117686A/en not_active Application Discontinuation
- 2010-03-23 KR KR1020117022445A patent/KR20110120352A/en active Application Filing
- 2010-03-23 WO PCT/JP2010/055488 patent/WO2010110466A1/en active Application Filing
Also Published As
Publication number | Publication date |
---|---|
US20120014830A1 (en) | 2012-01-19 |
WO2010110466A1 (en) | 2010-09-30 |
EP2412837B1 (en) | 2020-03-18 |
KR20140117686A (en) | 2014-10-07 |
JP2010248620A (en) | 2010-11-04 |
KR20110120352A (en) | 2011-11-03 |
CN102361999A (en) | 2012-02-22 |
EP2412837A4 (en) | 2014-04-09 |
CN102361999B (en) | 2014-06-11 |
EP2412837B8 (en) | 2020-04-29 |
EP2412837A1 (en) | 2012-02-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP5546911B2 (en) | Ferritic stainless steel sheet with excellent heat resistance and workability | |
JP5546922B2 (en) | Ferritic stainless steel sheet with excellent heat resistance and workability and method for producing the same | |
EP2692889B1 (en) | Ferritic stainless steel sheet having excellent heat resistance and processability, and method for producing same | |
JP5297630B2 (en) | Ferritic stainless steel plate with excellent heat resistance | |
JP5793459B2 (en) | Heat-resistant ferritic stainless steel cold-rolled steel sheet excellent in workability, ferritic stainless hot-rolled steel sheet for cold-rolled material, and production method thereof | |
JP4498950B2 (en) | Ferritic stainless steel sheet for exhaust parts with excellent workability and manufacturing method thereof | |
JP5709875B2 (en) | Heat-resistant ferritic stainless steel sheet with excellent oxidation resistance | |
JP5025671B2 (en) | Ferritic stainless steel sheet excellent in high temperature strength and method for producing the same | |
JP5141296B2 (en) | Ferritic stainless steel with excellent high temperature strength and toughness | |
JP5125600B2 (en) | Ferritic stainless steel with excellent high-temperature strength, steam oxidation resistance and workability | |
WO2018181060A1 (en) | Ferrite stainless steel sheet and production method therefor, and exhaust components | |
JP2019173042A (en) | Ferritic stainless steel sheet excellent in heat resistance, exhaust component, and manufacturing method therefor | |
JP5208450B2 (en) | Cr-containing steel with excellent thermal fatigue properties | |
JP5937861B2 (en) | Heat-resistant ferritic stainless steel sheet with excellent weldability | |
JP5677819B2 (en) | Ferritic stainless steel plate with excellent oxidation resistance |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20121105 |
|
A131 | Notification of reasons for refusal |
Free format text: JAPANESE INTERMEDIATE CODE: A131 Effective date: 20140107 |
|
A521 | Request for written amendment filed |
Free format text: JAPANESE INTERMEDIATE CODE: A523 Effective date: 20140307 |
|
TRDD | Decision of grant or rejection written | ||
A01 | Written decision to grant a patent or to grant a registration (utility model) |
Free format text: JAPANESE INTERMEDIATE CODE: A01 Effective date: 20140422 |
|
A61 | First payment of annual fees (during grant procedure) |
Free format text: JAPANESE INTERMEDIATE CODE: A61 Effective date: 20140514 |
|
R150 | Certificate of patent or registration of utility model |
Ref document number: 5546911 Country of ref document: JP Free format text: JAPANESE INTERMEDIATE CODE: R150 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
R371 | Transfer withdrawn |
Free format text: JAPANESE INTERMEDIATE CODE: R371 |
|
S531 | Written request for registration of change of domicile |
Free format text: JAPANESE INTERMEDIATE CODE: R313531 |
|
S533 | Written request for registration of change of name |
Free format text: JAPANESE INTERMEDIATE CODE: R313533 |
|
R350 | Written notification of registration of transfer |
Free format text: JAPANESE INTERMEDIATE CODE: R350 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |
|
R250 | Receipt of annual fees |
Free format text: JAPANESE INTERMEDIATE CODE: R250 |