WO1991014796A1 - Heat-resistant ferritic stainless steel excellent in low-temperature toughness, weldability and heat resistance - Google Patents

Heat-resistant ferritic stainless steel excellent in low-temperature toughness, weldability and heat resistance Download PDF

Info

Publication number
WO1991014796A1
WO1991014796A1 PCT/JP1991/000344 JP9100344W WO9114796A1 WO 1991014796 A1 WO1991014796 A1 WO 1991014796A1 JP 9100344 W JP9100344 W JP 9100344W WO 9114796 A1 WO9114796 A1 WO 9114796A1
Authority
WO
WIPO (PCT)
Prior art keywords
less
stainless steel
temperature
heat
weldability
Prior art date
Application number
PCT/JP1991/000344
Other languages
French (fr)
Japanese (ja)
Inventor
Yoshihiro Uematsu
Naoto Hiramatsu
Sadayuki Nakamura
Original Assignee
Nisshin Steel Co., Ltd.
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nisshin Steel Co., Ltd. filed Critical Nisshin Steel Co., Ltd.
Priority to EP91906263A priority Critical patent/EP0478790B1/en
Priority to CA002056362A priority patent/CA2056362C/en
Priority to KR1019910701642A priority patent/KR0180206B1/en
Priority to DE69110816T priority patent/DE69110816T2/en
Publication of WO1991014796A1 publication Critical patent/WO1991014796A1/en

Links

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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum

Definitions

  • the present invention relates to a ferritic heat-resistant stainless steel having excellent low-temperature toughness, weldability and heat resistance, and more particularly, to the exhaust gas path of an automobile engine.
  • Part of the steel in particular, relates to a heat-resistant stainless steel suitable for forming a high-temperature path from the engine to the converter.
  • Austenitic stainless steel represented by SUS 304 is considered to be a promising material for the above applications due to its excellent workability and good weldability. ing. However, since austenitic stainless steel has a large thermal expansion coefficient, thermal fatigue fracture due to thermal stress generated during use in applications where heating and cooling are required. Is concerned 1 is done. In addition, austenitic stainless steels have a large thermal expansion difference from surface oxides, so that surface oxides are easily peeled off by heating and cooling. From such a thing,
  • Ni-based alloys such as Inconel 600 have been applied to part of the vehicle exhaust gas path.
  • This alloy material is a promising material because it has a low coefficient of thermal expansion, excellent high-temperature oxidation characteristics such as adhesion of surface oxides, and excellent high-temperature strength.
  • it since it is a very expensive material, it has not been widely used.
  • ferritic stainless steel is less expensive than austenitic stainless steel.
  • it has excellent thermal fatigue characteristics due to its small coefficient of thermal expansion, so it is considered to be suitable for applications that are subject to the temperature cycle of heating and cooling.
  • ferrite stainless steels represented by Type 409 and SUS430 have begun to be used in some of the automotive exhaust gas paths. These materials have the property that their strength drops significantly above 900 ° C, which causes high temperature fatigue fracture due to insufficient strength.
  • the addition of such alloying elements and the increase in the amount of Cr generally significantly degrade the impact toughness of (1), and also increase weldability. Also, the workability becomes remarkably inferior.
  • austenitic and austenitic materials that can simultaneously satisfy various properties such as high-temperature strength, oxidation resistance, heat resistance, toughness, weldability, and additivity. At present, no ferrite system has emerged. If the ferritic stainless steel has the above-mentioned properties, it has the heat resistance and high-temperature strength of the layer, and can be manufactured, processed and welded. If ferritic stainless steels with excellent low-temperature toughness can be obtained, very promising materials can be obtained for special applications as described above. You.
  • Japanese Unexamined Patent Publication (Kokai) No. 64-8254 discloses the low-temperature toughness of ferritic stainless steel for such applications.
  • Japanese Patent Publication No. 59-52226 and Japanese Patent Publication No. 61-44121 disclose that the addition of Cu and Ni significantly lowers S, thereby reducing chlorine emissions.
  • a ferrite stainless steel with improved rust resistance to on and improved acidity is disclosed. However, if high temperature strength, heat resistance, weldability, low temperature toughness, etc. are to be fully taught. There is no time.
  • the object of the present invention is to expose the members of the vehicle exhaust gas path, especially to the high temperature between the engine and the engine.
  • the present invention provides, in weight percent,
  • the ratio of M n% / S% is 200 or more
  • [Nb] is equal to or greater than 0.2
  • the present invention relates to the above steel,
  • FIG. 1 is a diagram showing an example of the results of a high-temperature tensile test which led to the present invention, and is a relationship diagram between the amount of M 0 and the high-temperature tensile strength.
  • Fig. 2 is a diagram showing an example of the results of a high-temperature oxidation test, showing the relationship between the Mn content and the scale separation.
  • Fig. 3 is a graph showing the relationship between Mn / S and critical strain, showing an example of the results of a welding hot cracking test.
  • Fig. 4 is a diagram showing an example of the results of the Charpy impact test, showing the relationship between the Cu content and the values of the Charpy impact test.
  • Fig. 1 shows the basic composition of Fe-18% Cr-0.45% Nb from the viewpoint of high-temperature strength, which is an important property required for the material.
  • the results of examining the effects of M 0 and Cu on the results are shown.
  • the high-temperature strength was improved by adding 1% or more of M0.
  • the high-temperature strength of the composite addition of Mo-Cu is higher than that of the single addition of M0. Therefore, we found that composite addition of M0 and Cu is effective for materials that require high-temperature strength.
  • Figure 2 shows the effect of Mn on the scale release resistance of the high-temperature oxidation characteristics, another important characteristic.
  • the test was performed by changing the amount of Mn using Fe-18% Cr-0.45% Nb as the basic composition, and performing continuous oxidation at 900 ° C and 1000 ° C for 100 hours in air.
  • the scale separation was investigated. As a result, scale separation was suppressed by adding 0.6% or more at all test temperatures. Therefore, we have found that Mn raises the oxidation resistance limit of ferritic stainless steel.
  • Fig. 3 shows the basic composition of Fe-18% Cr-0.45% Nb, and the addition of appropriate amounts of M0 and Cu, which were effective in Fig. 1, and Mn and S
  • M0 and Cu which were effective in Fig. 1
  • Mn and S The effect of the Mn / S ratio on welding hot cracking was investigated by varying the temperature.
  • Welding hot cracking In the test, a 1.2-ram-thick cold-rolled annealed plate was prepared, processed into a 40 mm x 200 mm test piece, and TIG welding was performed with both ends of the test piece held and tensile stress applied in the longitudinal direction. Therefore, the minimum strain at which cracking began to occur was defined as the critical strain, and this was used as an index of the hot cracking susceptibility. As can be seen from Fig.
  • Fig. 4 shows the basic composition of Fe-18% Cr-0.45% Nb in order to grasp the toughness of the product, and the effect of Mo and Cu in order to examine the effect of Mo and Cu.
  • the impact value decreases with the addition of M0, which is the same as the conventionally known results; and the toughness increases with the addition of CU.
  • M0 which is the same as the conventionally known results
  • the toughness increases with the addition of CU.
  • Tsu the impact toughness at low temperatures could be improved by the combined addition of Ni and M0.
  • the present invention is based on the fact that the present invention is excellent in high-temperature strength, thermal fatigue properties and oxidation resistance, and is excellent in weldability and low-temperature toughness. It is intended to provide ferritic stainless steels with good lumbarance.
  • C and N are generally important elements for increasing the high-temperature strength, but the higher the content, the lower the oxidation resistance, workability and toughness. Come. Also, C and N form a compound with Nb, and reduce the effective Nb content in the ferrite phase. Therefore, it is desirable that C and N be low, and each should be 0.03% or less.
  • Si is an effective element for improving oxidation resistance. However, if added in excess, the hardness will increase and the workability and toughness will decrease, so the range is 0.1 to 0.8%.
  • Mn As shown in the above test results, Mn fixes S that is harmful to welding hot cracking in the form of MnS, and removes and reduces S in the weld metal. Although reduction of S itself is effective, it was found that it was good if the relationship of M n / S ⁇ 200 was satisfied. On the other hand, Mn is, as described above, a scale-resistant separation. By adding 0.6% or more in terms of properties, the resistance to scalability is improved. Therefore, Mn must be in the range of 0.6 to 2.0 and must satisfy the relationship of Mn / S ⁇ 200.
  • S is harmful to the above-mentioned hot cracking of the weld, so it is desirable to keep it as low as possible, and the lower the pressure, the higher the production cost. .
  • the upper limit of S is set to 0.006% because sufficient hot-hot cracking resistance is caused by the action of Mn as described above.
  • Ni has an effect similar to that of CU, as can be seen from the example. However, if it is added excessively, precipitation of the austenite phase occurs at high temperatures, and there is a concern that the thermal fatigue properties may be reduced due to an increase in the thermal expansion coefficient. Therefore, it was found that Ni + Cu must satisfy the relationship of 4% or less in the composite addition with Cu, which is the austenite-forming element. Based on these results, the upper limit was set to 4%.
  • Cr Cr is an element indispensable for improving corrosion resistance and oxidation resistance.
  • the lower limit is set to 17% because it is necessary to add 17% or more to maintain the oxidizing property of shochu above 900 ° C. From the viewpoint of oxidizing properties, the higher the Cr, the more favorable the force. If added in excess, the steel will become brittle and the workability will also deteriorate due to the increase in hardness.
  • Is 25% c Nb Nb is an element necessary for maintaining high-temperature strength. It also has a positive effect on improving workability and oxidation resistance, and on pipe forming by high frequency welding. As can be seen from the results of the high temperature tensile test in Table 2 below, at least 0.2% must be added to improve the high temperature strength. Since Nb produces a compound composed of C and N, the solute Nb decreases depending on the amounts of C and N even if the lower limit is simply set to 0.2%, and the high-temperature strength decreases. The effect of Nb on it is reduced. I did
  • Nb is equal to or more than 0.2% according to the following equation.
  • the upper limit of Nb is set to 0.8% so as to maintain sufficient high-temperature strength and not significantly affect the susceptibility to hot cracking.
  • Mo increases the high-temperature strength as added as described in the above test results. It is also effective in improving high-temperature oxidation and corrosion resistance of shochu. On the other hand, if added excessively, the toughness at low temperatures is significantly reduced, and the manufacturability and workability are also reduced. For this reason, it is 1.0-4.5%, preferably 2,0-4.5%, and more preferably more than 2.5-4.5%.
  • Cu is also an extremely effective element in terms of toughness as described in the above test results, and is an important element of the steel of the present invention. Toughness As shown in Fig. 4, the lower limit was set to 0.1% because it is necessary to obtain 0.1% or more as shown in Fig. 4. On the other hand, if added excessively, it becomes hard and impairs workability. The upper limit is set to 2.5% because it has a significant adverse effect on hot workability.
  • a 1 improves high temperature oxidation resistance. However, if added excessively, it may cause problems in manufacturability and weldability, so the upper limit is set to 0.5%.
  • T i increases high-temperature strength and improves workability.
  • the upper limit is set to 0.5%.
  • V V, like Ti, also increases the high-temperature strength and improves workability. However, excessive addition results in a decrease in strength. Therefore, the upper limit is set to 0.5%.
  • Zr increases high-temperature strength and improves high-temperature oxidation characteristics. However, if added in excess, the strength is reduced, so the upper limit is set to 1.0%.
  • ⁇ ⁇ As in the case of ⁇ , the high-temperature strength is increased and workability is improved. However, if added in excess, the strength will be reduced, so the upper limit should be 1.5%.
  • B B improves hot workability, increases high-temperature strength, and improves workability.
  • the upper limit is set to 0.01% because excessive addition causes a reduction in hot workability.
  • REM A rare earth element improves hot workability by adding a small amount, and improves oxidation resistance, especially the adhesion of the scale. However, if added excessively, hot workability reverses. Therefore, the upper limit is set to 0.1%.
  • Table 1 shows the chemical component values of the test materials.
  • M1 to M21 are steels of the present invention, and M22 to M30 are comparative steels. These steels were made in the laboratory into 30kg lump and forged into 25mm0 round bars and 25mni thick plates. The round bars were annealed at 950 ° C to 1100 ° C and processed into JIS standard high temperature tensile test specimens. ⁇ After cutting, the sheet is extracted from the furnace at 1200 ° C and hot-rolled to form a hot-rolled sheet with a thickness of 5 mm, annealed at 950 to 1100 ° C, and partly as it is. It was processed into a sharp impact test piece. The rest was subjected to repeated cold rolling and annealing, and a high-temperature oxidation test was performed at a thickness of 2 mm, and a hot cracking test was performed at a thickness of 1.2 mm.
  • Table 2 shows the high-temperature tensile strength obtained by the high-temperature tensile test performed in accordance with the JIS standard, the scale release amount obtained by continuous oxidation test at 900 ° C and 1000 ° C for 100 hours, and the text.
  • the steel has excellent high-temperature strength and high-temperature oxidation resistance, excellent resistance to high-temperature cracking at welding, and is also a ferritic stainless steel.
  • the above-mentioned excellent stainless steel for heat resistance having improved low-temperature toughness which is a disadvantage of the above, was obtained. Therefore, especially in the future, materials for exhaust gas systems that respond to high output and high performance of the engine, especially between the engine and the converter It is possible to provide a useful new product as a processed pipe member having a welded joint formed by welding.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Exhaust Silencers (AREA)
  • Heat Treatment Of Sheet Steel (AREA)

Abstract

A heat-resistant ferritic stainless steel improved in low-temperature toughness, prevented from undergoing high-temperature weld crack, and useful as a material of a passage of automobile exhaust gas, particularly a passage exposed to high temperature between an engine and a converter, which comprises up to 0.03 % of carbon, 0.1 to 0.8 % of silicon, 0.6 to 2.0 % of manganese, up to 0,006 % of sulfur, up to 4 % of nickel, 17.0 to 25.0 % of chronium, 0.2 to 0.8 % of niobium, 1.0 to 4.5 % of molybdenum, 0.1 to 2.5 % of copper, up to 0.03 % of nitrogen, and optionally a necessary amount of at least one of aluminum, titanium, vanadium, zirconium, tungsten, boron and REM, wherein the manganese to sulfur ratio is 200 or above, [Nb]=Nb % - 8(C % + N %) » 0.2, and Ni % + Cu % « 4, the balance being iron and inevitable impurities in the production process.

Description

λ 明 細 書 低温靭性， 溶接性お よ び耐熱性に優れた フ ェ ラ イ ト 系 耐熱用 ス テ ン レ ス鋼 技術分野 λ specification Ferrite-based heat-resistant stainless steel with excellent low-temperature toughness, weldability and heat resistance
〔産業上の利用分野〕  [Industrial applications]
本発明 は， 低温靭性， 溶接性お よ び耐熱性に優れた フ ェ ラ イ ト 系耐熱用 ス テ ン レ ス 鋼 に係 り ， 詳 し '； は， 自 動車エ ン ジ ン の排ガス経路の一部， 特にエ ン ジ ン ら コ ンバ ー 夕 に至 る ま での高温部の経路を構成す る Ο に適 し た耐熱用 ス テ ン レ ス鋼に関する 。  TECHNICAL FIELD The present invention relates to a ferritic heat-resistant stainless steel having excellent low-temperature toughness, weldability and heat resistance, and more particularly, to the exhaust gas path of an automobile engine. Part of the steel, in particular, relates to a heat-resistant stainless steel suitable for forming a high-temperature path from the engine to the converter.
〔発明の背景お よ び従来技術〕  [Background of the Invention and Prior Art]
近年， 自 動車の排気ガス に よ る大気汚染が大 き な問 題 と な っ てお り ， 排気ガス 中の Ν 〇 χ , H C ， C 0 な どの量が公害防止の観点か ら規制 さ れて き たが， 最近 . では酸性雨な どの点か ら規制が よ り 厳 し く な る 傾向 に あ る。 従 っ て排気ガス の浄化効率の一層の向上が必要 とな っ て き た。 In recent years, automatic cars by that air pollution in the exhaust gas is Ri tail Tsu Do a large deal of problems, Ν 〇 χ in the exhaust gas, HC, C 0 of which amount is viewpoint et al regulation of pollution prevention In recent years, however, regulations have tended to become more stringent from points such as acid rain. Therefore, further improvement of exhaust gas purification efficiency has been required.
他方， こ の浄化効率の向上に加え， エ ン ジ ン の高出 力化あ る いは性能ァ ッ プの要求の高ま り か ら も 自動車 の排ガス温度は上昇す る傾向 にあ る。 こ の よ う な背景 か ら， 排気ガス系統の部材は運転中 に一層高温に曝 さ れる こ と にな る 。 特にエ ン ジ ン と排ガス浄化機器の 二 ンバ一 夕 と の間の部材， 例えばェキ ゾ一ス ト マ二ホ ー ル ドゃデュ ア ルチ ュ ーブ等は よ り 高温にな る こ と は避 け られない。 そ して， か よ う な部材は， エ ン ジ ン の駆 動並びに走行に よ る振動に よ っ て機械的な応力変動を 受け， ま た運転パタ ー ン に依存 した加熱一冷却サ イ ク ルゃ， 場合に よ っ ては寒冷地での低温への冷却 と い つ た大き な温度変動を受け る な ど， 機械的に も 温度的に も き わめて過酷な状況下に さ ら さ れ る こ と にな る 。 On the other hand, in addition to the improvement in purification efficiency, the exhaust gas temperature of automobiles tends to increase due to the demand for higher output power and higher performance of engines. Against this background, exhaust system components are exposed to higher temperatures during operation. In particular, engines and exhaust gas purification equipment It is inevitable that parts between the chamber and the chamber, such as exhaust manifold dual tubes, will become hotter. Such members are subject to mechanical stress fluctuations due to engine driving and vibration caused by running, and also have a heating / cooling size dependent on the operating pattern. Under extreme conditions, both mechanically and thermally, such as when subjected to large temperature fluctuations, such as cooling to low temperatures in cold climates, and in some cases. Will be affected.
ステ ン レ ス鋼な どの耐熱鋼を こ れ ら の用途に適用す る場合， 耐熱性に優れ る こ と は無論であ る 力 こ れ ら の部材は溶接接合部を有す る （パイ プでは溶接造管 さ れる のが通常であ り ， ま た他の部材 と の接続 も溶接で 施工 さ れる こ とが多 い ので， 溶接性に優れ る こ と力 必要であ り ， それ らを加工す る 際の加工性に優れ る こ と も必要 と な る 。 したがっ て， ステ ン レ ス鋼であ る と い う 本来の酎食機能のほかに， こ れ らの用途では耐熱 性， 低温靭性， 溶接性お よ び加工性を同時に兼備す る こ とが重要な課題 とな る。  When applying heat-resistant steel such as stainless steel to these applications, it is obvious that heat resistance is excellent. These members have welded joints (pipes). In this case, pipes are usually welded, and connections to other members are often made by welding. Therefore, it is necessary to have excellent weldability and force. It is also necessary to have excellent workability during processing, so in addition to the original shochu-eating function of stainless steel, heat resistance, It is important to combine low-temperature toughness, weldability, and workability at the same time.
S U S 304に代表 さ れる オー ステナイ ト 系ス テ ン レ ス鋼 は加工性に優れ且つ溶接性 も 良好であ る ため に上記の よ う な用途に対 して有望な材料であ る と考え られてい る。 しか しオ ー ス テナイ ト 系ス テ ン レ ス 鋼は熱膨脹係 数が大き い こ とか ら， 加熱一 冷却を受け る よ う な用途 では使用 中 に発生す る熱応力 に よ る熱疲労破壊が懸念 1 さ れ る 。 ま た， オ ー ス テナイ ト 系 ス テ ン レ ス 鋼は表面 酸化物 と の熱膨脹差が大き いため， 加熱 - 冷却に よ つ て表面酸化物が剥離 しやすい。 こ の よ う な こ と か ら，Austenitic stainless steel represented by SUS 304 is considered to be a promising material for the above applications due to its excellent workability and good weldability. ing. However, since austenitic stainless steel has a large thermal expansion coefficient, thermal fatigue fracture due to thermal stress generated during use in applications where heating and cooling are required. Is concerned 1 is done. In addition, austenitic stainless steels have a large thermal expansion difference from surface oxides, so that surface oxides are easily peeled off by heating and cooling. From such a thing,
Inconel 600に代表 さ れる N i基の合金が自 動車排ガ ス経路の一部に適用 さ れて い る 。 こ の合金材料は熱膨 脹係数が低 く . ま た表面酸化物の密着性な ど耐高温酸 化特性に優れ， かつ優れた高温強度を有 してい る の で 有望な材料であ る。 しか し， き わめて高価な材料であ る ため広 く 一般に使用 さ れ る に は至 っ ていない。 Ni-based alloys, such as Inconel 600, have been applied to part of the vehicle exhaust gas path. This alloy material is a promising material because it has a low coefficient of thermal expansion, excellent high-temperature oxidation characteristics such as adhesion of surface oxides, and excellent high-temperature strength. However, since it is a very expensive material, it has not been widely used.
—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 鋼に比べて安価であ る。 ま た熱膨脹係数 が小 さ いた め熱疲労特性に優れて い る ので加熱一 冷却 の温度サイ ク ルを受け る よ う な用途に適す る と考え ら れ る 。 そ の ため， 自動車排ガス経路の一部に対 して， Type409や SUS430で代表 さ れ る フ ェ ラ イ 卜 系ス テ ン レ ス鋼が使用 さ れ始めて い る 。 し力、 し， こ れ ら の材料は 900°C以上にな る と強度が著 し く 低下す る と い う 性質 があ り ， こ のために強度不足に よ る高温疲労破壊を起 こ す と い う 問題 と， 耐酸化限界を越え る と異常酸化を 起 こ す と い う 問題があ る。 こ れ ら の問題に対 し， 高温 強度を改善す る各種合金元素を添加 し， ま た耐酸化性 の改善を C r量の増量に よ っ て行 う こ と も可能であ る が， か よ う な合金元素の添加お よ び C r量の増量は一 般に鐧の衝撃靭性を著 し く 劣化さ せ， ま た溶接性お よ び加工性 も著 し く 劣 る よ う にな る。 On the other hand, ferritic stainless steel is less expensive than austenitic stainless steel. In addition, it has excellent thermal fatigue characteristics due to its small coefficient of thermal expansion, so it is considered to be suitable for applications that are subject to the temperature cycle of heating and cooling. For this reason, ferrite stainless steels represented by Type 409 and SUS430 have begun to be used in some of the automotive exhaust gas paths. These materials have the property that their strength drops significantly above 900 ° C, which causes high temperature fatigue fracture due to insufficient strength. There are two problems: the problem of oxidation, and the problem of abnormal oxidation when exceeding the oxidation resistance limit. To solve these problems, it is possible to add various alloying elements to improve the high-temperature strength and to improve the oxidation resistance by increasing the Cr content. The addition of such alloying elements and the increase in the amount of Cr generally significantly degrade the impact toughness of (1), and also increase weldability. Also, the workability becomes remarkably inferior.
こ の よ う に， 排気ガス浄化効率の向上， エ ン ジ ン の 高出力化お よ び高性能化な どの進展に伴っ て厳 し く な る耐用条件に適合す る ステ ン レ ス鋼材料， すなわ ち， 高温強度， 耐酸化性， 耐熱性， 靭性， 溶接性お よ び加 ェ性 と い っ た多性質を同時に満足でき且つ柽済的な材 料はオー ステナイ ト系お よ び フ ェ ラ イ ト 系 と も現状で は出現 していな い。 も し， フ ェ ラ イ ト 系ス テ ン レ ス 鋼 が有す る前記の特質を生か しなが ら， ―層の耐熱性 と 高温強度を有 し， 且つ製造性， 加工性， 溶接性お よ び 低温靭性に優れた フ ェ ラ イ ト 系ステ ン レ ス鋼が得 ら れ れば， 上記の よ う な特殊用途に対 して き わめて有望な 材料を得る こ とができ る。  As described above, stainless steel materials that meet the stricter service conditions that are becoming more stringent with improvements in exhaust gas purification efficiency, higher engine output, and higher performance. In other words, austenitic and austenitic materials that can simultaneously satisfy various properties such as high-temperature strength, oxidation resistance, heat resistance, toughness, weldability, and additivity. At present, no ferrite system has emerged. If the ferritic stainless steel has the above-mentioned properties, it has the heat resistance and high-temperature strength of the layer, and can be manufactured, processed and welded. If ferritic stainless steels with excellent low-temperature toughness can be obtained, very promising materials can be obtained for special applications as described above. You.
特開昭 64 - 8254号公報は， か よ う な用途への フ ェ ラ イ ト 系ス テ ン レ ス 鋼を開示す る 力 低温靭性について は不明であ る。 他方， 特公昭 5 9 - 52226号公報お よ び特 公昭 6 1 - 441 2 1号公報は C uと N iを添加 した う えで S を 極端に低下す る こ と に よ っ て塩素イ オ ン に対す る 発銹 抵抗性 と酎酸性を改善 した フ ェ ラ イ ト 系ステ ン レ ス鐧 を開示する が， 高温強度， 耐熱性， 溶接性， 低温靭性 等については全 く 教え る と こ ろ はない。  Japanese Unexamined Patent Publication (Kokai) No. 64-8254 discloses the low-temperature toughness of ferritic stainless steel for such applications. On the other hand, Japanese Patent Publication No. 59-52226 and Japanese Patent Publication No. 61-44121 disclose that the addition of Cu and Ni significantly lowers S, thereby reducing chlorine emissions. A ferrite stainless steel with improved rust resistance to on and improved acidity is disclosed. However, if high temperature strength, heat resistance, weldability, low temperature toughness, etc. are to be fully taught. There is no time.
〔発明の 目 的〕  [Purpose of the invention]
したが っ て本発明の 目 的 は， 自動車排ガス経路の部 材， と り わ けエ ン ジ ン と コ ン ノく一 夕 と の間の高温に曝 さ れ る 部材に要求 さ れ る過酷な前記の諸性質を同時に 満足す る フ ェ ラ イ ト 系 ス テ ン レ ス鋼を得る こ と ， と り わ け， フ ェ ラ イ ト 系 ス テ ン レ ス鋼 の本来 の欠点であ る 低温靭性を改善 し， ま た製造上お よ び施工上問題 と な る 溶接部の溶接高温割れを も 防止でき る フ ェ ラ イ ト 系 耐熱用 ス テ ン レ ス鐧を得る こ と にあ る 。 Therefore, the object of the present invention is to expose the members of the vehicle exhaust gas path, especially to the high temperature between the engine and the engine. Obtaining a ferritic stainless steel that simultaneously satisfies the above-mentioned severe properties required for a member to be manufactured, in particular, a ferritic steel A ferrite heat-resistant steel that can improve low-temperature toughness, which is an inherent drawback of stainless steel, and can also prevent weld hot cracking of welds, which is a problem in manufacturing and construction. It is in obtaining the tenth.
〔発明の開示〕  [Disclosure of the Invention]
本発明 は， 重量％ において，  The present invention provides, in weight percent,
C ： 0.03 %以下，  C: 0.03% or less,
S i ： 0.卜 0.8%，  S i: 0.8% 0.8%,
M n ： 0.6— 2.0% ,  M n: 0.6—2.0%,
S ： 0.006 %以下，  S: 0.006% or less,
N i ： 4 %以下，  N i: 4% or less,
C r ： 17.0- 25.0% ,  Cr: 17.0-25.0%,
N b ： 0.2- 0.8% ,  Nb: 0.2-0.8%,
M o : 1.0— 4.5% ,  M o: 1.0— 4.5%,
C u ： 0. 1~ 2.5% ,  Cu: 0.1 to 2.5%,
N ： 0.03 %以下，  N: 0.03% or less,
ただ し， 前記の範囲 において， However, in the above range,
M n% / S % の比が 200以上，  The ratio of M n% / S% is 200 or more,
〔 N b〕 = N b% - 8 ( C % + N % )  (Nb) = Nb%-8 (C% + N%)
の式に従 う 〔 N b〕 が 0.2以上， お よ び  [Nb] is equal to or greater than 0.2, and
N i % + C u%力 4 以下  N i% + Cu% force 4 or less
の関係を満足す る よ う に こ れ ら の元素を含有 し， 残 部が F eお よ び製造上の不可避的不純物か らな る 低温 靭性， 溶接性お よ び耐熱性に優れた フ ェ ラ イ ト 系耐熱 用 ステ ン レ ス鋼を提供する。 These elements are contained to satisfy the relationship of We provide ferrite-based heat-resistant stainless steel with excellent low-temperature toughness, weldability, and heat resistance, whose parts consist of Fe and inevitable impurities in production.
ま た， 本発明 は， 前記の鋼に， さ ら に  In addition, the present invention relates to the above steel,
A 1 ： 0.5%以下，  A 1: 0.5% or less,
T i ： 0.6%以下，  T i: 0.6% or less,
V ： 0.5%以下，  V: 0.5% or less,
Z r ： 1.0 %以下，  Zr: 1.0% or less,
W ： 1.5%以下，  W: 1.5% or less,
B ： 0.01 %以下，  B: 0.01% or less,
REM ： 0. 1 %以下  REM: 0.1% or less
の一種ま たは二種以上を含有 した低温靭性， 溶接性お よ び耐熱性に優れた フ ェ ラ イ ト 系耐熱用 ス テ ン レ ス鋼 を提供す る 。 To provide ferrite-based heat-resistant stainless steel containing one or two or more types and having excellent low-temperature toughness, weldability and heat resistance.
〔図面の簡単な説明〕  [Brief description of drawings]
第 1 図は本発明をなすに至 っ た高温引張試験結果の 例を示す M 0量 と高温引張強度 と の関係図であ る。  FIG. 1 is a diagram showing an example of the results of a high-temperature tensile test which led to the present invention, and is a relationship diagram between the amount of M 0 and the high-temperature tensile strength.
第 2 図 は高温酸化試験結果の例を示す M n量 とス ケ 一ル剝離量の関係図であ る。  Fig. 2 is a diagram showing an example of the results of a high-temperature oxidation test, showing the relationship between the Mn content and the scale separation.
第 3 図は溶接高温割れ試験結果の例を示す M n/S と 臨界歪量 と の関係図であ る。  Fig. 3 is a graph showing the relationship between Mn / S and critical strain, showing an example of the results of a welding hot cracking test.
第 4 図 は シ ャ ル ピー衝撃試験結果の例を示す C u量 と シ ャ ル ピー衝撃試験値の関係図であ る。  Fig. 4 is a diagram showing an example of the results of the Charpy impact test, showing the relationship between the Cu content and the values of the Charpy impact test.
〔発明の詳述〕 本発明者 ら は前記の 目 的を達成すべ く 試験研究を重 ね， 以下の如 き知見を得る こ と ができ た。 [Detailed Description of the Invention] The inventors of the present invention have conducted tests and researches to achieve the above-mentioned purpose, and have obtained the following findings.
第 1 図 は， 材料に要求さ れ る重要特性であ る高温強 度の観点か ら F e- 18% C r- 0.45% N bを基本組成 と し， 表示温度での高温引張強 さ に及ぼす M 0お よ び C uの影 響を調べた結果を示 した も のであ る。 同図 に見 ら れ る よ う に， M 0を 1 %以上添加す る こ と に よ っ て高温強 度が改善 さ れてい る 。 ま た， M o- C uの複合添加 に よ つ て M 0単独添加 よ り も高温強度が上昇 して い る 。 し たが っ て， 高温強度が要求 さ れ る材料では M 0と C uの 複合添加が有効であ る と の知見を得た。  Fig. 1 shows the basic composition of Fe-18% Cr-0.45% Nb from the viewpoint of high-temperature strength, which is an important property required for the material. The results of examining the effects of M 0 and Cu on the results are shown. As can be seen from the figure, the high-temperature strength was improved by adding 1% or more of M0. In addition, the high-temperature strength of the composite addition of Mo-Cu is higher than that of the single addition of M0. Therefore, we found that composite addition of M0 and Cu is effective for materials that require high-temperature strength.
第 2 図 は， も う 一方の重要特性であ る高温酸化特性 の う ち， 耐ス ケ ー ル剝離性について M nの影響を調べ た も のであ る 。 試験は F e- 18% C r- 0.45% N bを基本 組成 と して M n量を変化さ せ， 大気中で 900 °Cお よ び 1000 °C において 100時間の連続酸化を実施 し， スケ一 ル剝離量を調査 した。 その結果， いずれの試験温度で も を 0.6%以上添加す る こ と に よ っ て スケ ー ル剝離 が抑制 さ れた。 したが っ て， M nは フ ェラ イ ト 系ステ ン レ ス鋼の耐酸化限界を上昇 さ せ る と の知見を得た。  Figure 2 shows the effect of Mn on the scale release resistance of the high-temperature oxidation characteristics, another important characteristic. The test was performed by changing the amount of Mn using Fe-18% Cr-0.45% Nb as the basic composition, and performing continuous oxidation at 900 ° C and 1000 ° C for 100 hours in air. The scale separation was investigated. As a result, scale separation was suppressed by adding 0.6% or more at all test temperatures. Therefore, we have found that Mn raises the oxidation resistance limit of ferritic stainless steel.
第 3 図は， F e- 18% C r-0.45% N bを基本組成 と し， 第 1 図で効果の認め られた適量の M 0と C uを複合添加 した う え， M nと S を変動 さ せ， 溶接高温割れに及ぼ す M n/S 比の影響を調べた も のであ る。 溶接高温割れ 試験は， 1.2ram厚の冷延焼鈍板を作成 し， 40mm X 200mm の試験片に加工後， 試験片の両端を保持 して長手方向 に引張 り 応力 を付加 した状態にて T I G 溶接を行な い， 割れが発生 し始め る最小の ひずみ量を臨界歪量 と し， こ れを溶接高温割れ感受性の指標 と した。 第 3 図 に見 られる よ う に， M 0- C u複合添加の場合， M n/S 力 200 以上にな る と臨界歪量が増大 し， 溶接性が改善 さ れ る 効果が認め られた。 こ の結果， 溶接高温割れを改善す る ためには M n/S が 200以上 と な る適正量の M IIを添 加する こ とが有効であ る と の知見を得た。 Fig. 3 shows the basic composition of Fe-18% Cr-0.45% Nb, and the addition of appropriate amounts of M0 and Cu, which were effective in Fig. 1, and Mn and S The effect of the Mn / S ratio on welding hot cracking was investigated by varying the temperature. Welding hot cracking In the test, a 1.2-ram-thick cold-rolled annealed plate was prepared, processed into a 40 mm x 200 mm test piece, and TIG welding was performed with both ends of the test piece held and tensile stress applied in the longitudinal direction. Therefore, the minimum strain at which cracking began to occur was defined as the critical strain, and this was used as an index of the hot cracking susceptibility. As can be seen from Fig. 3, in the case of M0-Cu composite addition, when the Mn / S force exceeds 200, the effect of increasing the critical strain and improving the weldability was observed. . As a result, it has been found that it is effective to add an appropriate amount of MII with Mn / S of 200 or more in order to improve welding hot cracking.
第 4 図は， 製品 と しての靭性を把握す る ため に F e- 18% C r-0.45% N bを基本組成 と し， M oお よ び C uの 影響を調べる ために シ ャ ル ピー衝撃試験を実施 し た結 果であ る。 M 0を添加す る と衝撃値が低下す る こ と は 従来よ り 知 ら れてい る結果 と 同 じであ る 力；， さ ら に， C Uを複合添加す る こ と に よ り 靭性が改善さ れる と い う 新 しい知見を得る こ と がで き た。 中で も 4 % M 0添 加鐦の よ う に衝撃靭性が著 し く 低い も ので も ， C uを 複合添加する こ と に よ っ て十分に衝撃値が改善 さ れる こ とがわ力、 つ た。 ま た， N iお よ び M 0と の複合添加に よ つ て低温での衝撃靭性を改善でき る ごとが後記実施 例に示 した よ う に判明 した。 こ の こ と は重大な知見て あ り ， 冬期の低温環境下に さ ら さ れ る部材 （低温環境 でのエ ン ジ ン始動の よ う に， 低温で機械的振動が付与 さ れる エ ン ジ ン直結部材 · 具体的 に はマ二ホ ー ル ドゃ デュ ア ルチ ュ ー ブ） に は特に有効 と考え ら れ， 今後予 想 さ れ る ま す ま す厳 しい条件において も 使用可能 と な こ の よ う な知見事実に基づ き . 本発明 は高温強度， 熱疲労特性お よ び耐酸化性に優れ， かつ， 溶接性お よ び低温靭性に優れた ト ー タ ルバ ラ ン ス の良好な フ ェ ラ ィ ト 系ス テ ン レ ス鋼を提供す る も のであ る 。 Fig. 4 shows the basic composition of Fe-18% Cr-0.45% Nb in order to grasp the toughness of the product, and the effect of Mo and Cu in order to examine the effect of Mo and Cu. This is the result of a rupee impact test. The impact value decreases with the addition of M0, which is the same as the conventionally known results; and the toughness increases with the addition of CU. Has gained new insights that will be improved. Among them, even though the impact toughness is remarkably low as in the case of adding 4% M0, the impact value can be sufficiently improved by adding Cu in combination. , Tsu. In addition, it was revealed as shown in the examples below that the impact toughness at low temperatures could be improved by the combined addition of Ni and M0. This is a serious finding, and it is important to note that components exposed to low-temperature environments in winter (such as engine start-up in low-temperature environments are subject to mechanical vibration at low temperatures). It is considered to be particularly effective for engine directly connected members, specifically, manifolds (dual tubes), and is expected to be used under increasingly severe conditions in the future. The present invention is based on the fact that the present invention is excellent in high-temperature strength, thermal fatigue properties and oxidation resistance, and is excellent in weldability and low-temperature toughness. It is intended to provide ferritic stainless steels with good lumbarance.
以下に本発明鋼にお け る 各化学成分値の含有量を限 定 し た理由 を概説す る。  The reasons for limiting the content of each chemical component value in the steel of the present invention will be outlined below.
C お よ び N ： C と N は一般的 に は高温強度を高め る ために重要な元素であ る が， 反面含有量が多 く な る と 耐酸化性， 加工性な ら びに靭性の低下を来す。 ま た C と N は N bと の化合物をつ く り ， フ ェ ラ イ ト 相中の有 効 N b量を減少せ しめ る。 したが っ て， C と N は低い こ とが望 ま し く ， それぞれ 0. 03 %以下 とす る 。  C and N: C and N are generally important elements for increasing the high-temperature strength, but the higher the content, the lower the oxidation resistance, workability and toughness. Come. Also, C and N form a compound with Nb, and reduce the effective Nb content in the ferrite phase. Therefore, it is desirable that C and N be low, and each should be 0.03% or less.
S i : S iは耐酸化性の向上に は有効な元素であ る。 しか し， 過剰に添加する と硬さ が上昇 し加工性， 靭性 の低下す る よ う に な る ので 0. 1〜 0. 8 % の範囲 とす る。  Si: Si is an effective element for improving oxidation resistance. However, if added in excess, the hardness will increase and the workability and toughness will decrease, so the range is 0.1 to 0.8%.
M n ： M nは前述の試験結果に示 した よ う に溶接高温 割れに有害な S を M n S の形で固定 し， 溶接金属中 の S を除去， 減少せ しめ る 。 S 自身の低減 も有効であ る が M n / S ≥ 200の関係を満足すれば良好であ る こ とか 判明 した。 一方， M nは前述の よ う に耐スケ ー ル剝離 性の面で 0.6%以上添加する こ と に よ つ て耐ス ケ ー 儿 剝離性が改善 さ れ る。 したが っ て， M nは 0.6〜 2.0 の範囲 と し， 且つ M n/S ≥ 200の関係を満足す る こ と が必要であ る。 Mn: As shown in the above test results, Mn fixes S that is harmful to welding hot cracking in the form of MnS, and removes and reduces S in the weld metal. Although reduction of S itself is effective, it was found that it was good if the relationship of M n / S ≥ 200 was satisfied. On the other hand, Mn is, as described above, a scale-resistant separation. By adding 0.6% or more in terms of properties, the resistance to scalability is improved. Therefore, Mn must be in the range of 0.6 to 2.0 and must satisfy the relationship of Mn / S ≥ 200.
S ： S は上述の ご と く 溶接高温割れに対 して有害であ る ので可能な限 り 低いほ う が望ま しいカ ， 低 く 押 さ え る ほ ど製造 コ ス ト の上昇を招 く 。 本発明鋼において は S は 0.006% ま で許容 して も前述の よ う に M nの作用 に よ つ て十分な耐溶接高温割れを有す る の で S の上限を 0.006 % とす る。  S: S is harmful to the above-mentioned hot cracking of the weld, so it is desirable to keep it as low as possible, and the lower the pressure, the higher the production cost. . In the steel of the present invention, even if S is allowed up to 0.006%, the upper limit of S is set to 0.006% because sufficient hot-hot cracking resistance is caused by the action of Mn as described above.
N i ： N iは実施例力、 らわか る よ う に， C Uと 同様な 靭性改善効果を も た らす。 しか し， 過剰に添加す る と 高温においてオーステナイ ト 相の析出な どが起 こ り ， 熱膨脹係数の増大な どに よ る 熱疲労特性の低下な どが 懸念 さ れ る 。 こ のためオー ス テナイ ト 生成元素であ る C uと の複合添加において， N i + C uが 4 %以内の関 係を満足す る 必要があ る こ とがわか っ た。 こ の結果か ら上限を 4 % と した。  Ni: Ni has an effect similar to that of CU, as can be seen from the example. However, if it is added excessively, precipitation of the austenite phase occurs at high temperatures, and there is a concern that the thermal fatigue properties may be reduced due to an increase in the thermal expansion coefficient. Therefore, it was found that Ni + Cu must satisfy the relationship of 4% or less in the composite addition with Cu, which is the austenite-forming element. Based on these results, the upper limit was set to 4%.
C r ： C rは耐食性， 耐酸化性の改善に不可欠の元素 であ る。 下限を 17% と したのは 900°C以上の酎酸化性 を維持す る ためには 17%以上の添加を必要 とする か ら であ る。 酎酸化性の面か ら C rは高いほ ど好ま しい力、， 過剰に添加す る と鋼の脆化を招 き ， ま た硬さ の上昇に よ っ て加工性 も劣化す る ので上限は 25% とす る c N b ： N bは高温強度を維持せ しめ る の に必要な元 素であ る 。 ま た加工性お よ び耐酸化性の改善や高周波 溶接に よ る造管性に も 好影響を及ぼす。 後述の第 2 表 の高温引張試験結果か ら も判 る よ う に高温強度を改善 す る ために は少な く と も 0.2 %添加する 必要があ る 。 し力、 し N bは C と N に よ る 化合物をつ く る のでただ単 に下限を 0.2% と して も C と N の量に よ っ て固溶 N b は減少 し， 高温強度に及ぼす N bの効果は減少す る 。 し たカ っ て， Cr: Cr is an element indispensable for improving corrosion resistance and oxidation resistance. The lower limit is set to 17% because it is necessary to add 17% or more to maintain the oxidizing property of shochu above 900 ° C. From the viewpoint of oxidizing properties, the higher the Cr, the more favorable the force. If added in excess, the steel will become brittle and the workability will also deteriorate due to the increase in hardness. Is 25% c Nb: Nb is an element necessary for maintaining high-temperature strength. It also has a positive effect on improving workability and oxidation resistance, and on pipe forming by high frequency welding. As can be seen from the results of the high temperature tensile test in Table 2 below, at least 0.2% must be added to improve the high temperature strength. Since Nb produces a compound composed of C and N, the solute Nb decreases depending on the amounts of C and N even if the lower limit is simply set to 0.2%, and the high-temperature strength decreases. The effect of Nb on it is reduced. I did
〔 N b〕 二 N b% - 8 (C % + N %  (Nb) 2 Nb%-8 (C% + N%
の式に従 う 〔 N b〕 が 0 · 2 %以上 と な る 関係を満足す る こ とが必要であ る。 一方， N bを過剰に添加す る と溶 接高温割れ感受性が高 く な る 。 十分な高温強度を維持 し， な おかつ溶接高温割れ感受性に あ ま り 影響を及ぼ さ な い よ う に N bの上限を 0.8% とす る c It is necessary to satisfy the relation that [Nb] is equal to or more than 0.2% according to the following equation. On the other hand, if Nb is added excessively, the susceptibility to welding hot cracking increases. The upper limit of Nb is set to 0.8% so as to maintain sufficient high-temperature strength and not significantly affect the susceptibility to hot cracking.
0 ： M oは前述の試験結果で も述べた よ う に添加す る ほ ど高温強度を上昇 さ せ る 。 ま た酎高温酸化お よ び 耐食性の改善に も有効であ る。 一方， 過剰に添加す る と低温での靭性を著 し く 低下 さ せ， ま た製造性， 加工 性の低下を き たす。 こ のため， 1.0〜 4.5% , 好ま し く は 2, 0〜 4.5% , さ ら に好ま し く は 2.5超え〜 4.5% % とす る。  0: Mo increases the high-temperature strength as added as described in the above test results. It is also effective in improving high-temperature oxidation and corrosion resistance of shochu. On the other hand, if added excessively, the toughness at low temperatures is significantly reduced, and the manufacturability and workability are also reduced. For this reason, it is 1.0-4.5%, preferably 2,0-4.5%, and more preferably more than 2.5-4.5%.
C u ： C uも前述の試験結果で述べた よ う に靭性面で 非常に有効な元素で本発明鋼の重要な元素であ る 。 靭 性改善効果を得る に は第 4 図 に見 られ る よう に 0.1 % 以上必要であ る ため， 下限値を 0.1% と した。 一方， 過剰に添加す る と硬質 と な り 加工性を害す る 。 ま た， 熱間加工性に も著 し く 悪影響を及ぼすので上限を 2.5 % とする。 Cu: Cu is also an extremely effective element in terms of toughness as described in the above test results, and is an important element of the steel of the present invention. Toughness As shown in Fig. 4, the lower limit was set to 0.1% because it is necessary to obtain 0.1% or more as shown in Fig. 4. On the other hand, if added excessively, it becomes hard and impairs workability. The upper limit is set to 2.5% because it has a significant adverse effect on hot workability.
A 1 : A 1は耐高温酸化特性を改善す る。 しか し過 剰に添加す る と製造性， 溶接性で問題にな る ため上限 を 0.5% とす る。  A 1: A 1 improves high temperature oxidation resistance. However, if added excessively, it may cause problems in manufacturability and weldability, so the upper limit is set to 0.5%.
T i : T iは高温強度を上昇さ せ， 加工性 も 改善す る。 しか し A 1同様過剰に添加する と製造性， 溶接性 で問題にな る ため . 上限を 0.5 % とする。  T i: T i increases high-temperature strength and improves workability. However, as in A1, excessive addition causes problems in manufacturability and weldability. The upper limit is set to 0.5%.
V ： V も T iと 同様に高温強度を上昇さ せ， 加工性 を改善す る。 しか し， 過剰に添加する と逆に強度の低 下を招 く 。 よ っ て上限を 0.5% とす る。  V: V, like Ti, also increases the high-temperature strength and improves workability. However, excessive addition results in a decrease in strength. Therefore, the upper limit is set to 0.5%.
Z r ： Z rは高温強度を上昇さ せ， 高温酸化特性を 改善する。 しか し， 過剰に添加す る と強度の低下を招 く ので上限を 1.0% とす る。  Zr: Zr increases high-temperature strength and improves high-temperature oxidation characteristics. However, if added in excess, the strength is reduced, so the upper limit is set to 1.0%.
^¥ : も 丁 1ゃ 同様， 高温強度を上昇さ せ， 加工 . 性を改善す る。 しか し過剰に添加する と強度の低下を 招 く ので上限を 1.5% とす る。  ^ ¥: As in the case of ゃ, the high-temperature strength is increased and workability is improved. However, if added in excess, the strength will be reduced, so the upper limit should be 1.5%.
B ： B は熱間加工性を改善 し高温強度 も上昇 さ せ， 加工性を も 改善す る 。 しか し， 過剰に添加す る とかえ つ て熱間加工性の低下を招 く ため， 上限を 0.01 % とす る o REM ： 希土類元素は微量添加 に よ っ て熱間加工性を 改善 し， 耐酸化性特にス ケ ー ルの密着性を改善す る c しか し， 過剰に添加す る と逆に熱間加工性の低下を招 く ため， 上限を 0. 1 % とす る 。 B: B improves hot workability, increases high-temperature strength, and improves workability. However, the upper limit is set to 0.01% because excessive addition causes a reduction in hot workability. REM: A rare earth element improves hot workability by adding a small amount, and improves oxidation resistance, especially the adhesion of the scale. However, if added excessively, hot workability reverses. Therefore, the upper limit is set to 0.1%.
〔実施例〕  〔Example〕
第 1 表に供試材の化学成分値を示 した。 M 1 〜 M 21 は本発明鋼で， M 22〜 M 30は比較鋼であ る。 こ れ ら の 鋼は， 実験室にて 30kg鐧塊を作成 し， 25mm 0 の丸棒 と 25mni厚の板に鍛造 し た。 丸棒は 950°C〜 1100°Cで焼鈍 後， JIS標準の高温引張試験片に加工 した。 锻造板は 切削後 1200°Cで炉か ら抽出 して熱間圧延を施 し， 厚 さ 5 mmの熱延板 と し， 950て〜 1100 °Cで焼鈍後， 一部は その ま ま で シ ャ ル ピー衝撃試験片に加工 した。 残部は 冷延， 焼鈍を繰 り 返 し， 2 mmの板厚にて高温酸化試験 を実施 し， 1.2mmの板厚において溶接高温割れ試験を 実施 した。  Table 1 shows the chemical component values of the test materials. M1 to M21 are steels of the present invention, and M22 to M30 are comparative steels. These steels were made in the laboratory into 30kg lump and forged into 25mm0 round bars and 25mni thick plates. The round bars were annealed at 950 ° C to 1100 ° C and processed into JIS standard high temperature tensile test specimens.锻 After cutting, the sheet is extracted from the furnace at 1200 ° C and hot-rolled to form a hot-rolled sheet with a thickness of 5 mm, annealed at 950 to 1100 ° C, and partly as it is. It was processed into a sharp impact test piece. The rest was subjected to repeated cold rolling and annealing, and a high-temperature oxidation test was performed at a thickness of 2 mm, and a hot cracking test was performed at a thickness of 1.2 mm.
第 2 表に， J I S標準で実施 した高温引張試験に よ る 高温引張強 さ ， 900°Cお よ び 1000°Cでの 100時間の連 . 続酸化試験に よ る スケ ー ル剝離量， 本文に記載 した溶 接高温割れ試験に よ る 溶接時の臨界歪量， お よ び 4.5 mmの板厚で V ノ ツ チ シ ャ ル ピー衝撃試験片で実施 し た シ ャ ル ビ 一衝撃試験の結果を示 した。  Table 2 shows the high-temperature tensile strength obtained by the high-temperature tensile test performed in accordance with the JIS standard, the scale release amount obtained by continuous oxidation test at 900 ° C and 1000 ° C for 100 hours, and the text. The critical strain at the time of welding by the welding hot cracking test described in Section 4 and the Charpy one-impact test performed on a V-notch sheary impact test specimen with a plate thickness of 4.5 mm. The results are shown.
第 2 表の結果か ら， N b. M oお よ び N iを添加す る こ と に よ っ て高温強度が上昇 してい る こ とがわか る 。 ま た M oお よ び C 11の複合添加鋼は さ ら に高温強度の上昇 が見 られ る。 連続高温酸化試験結果では 900 °Cお よ び 1 000 °C と も M n量が 0. 6 %を越え る と耐ス ケ ー ル剝離性 が著 し く 改善さ れる こ とがわかる 。 ま た， 溶接高温割 れ試験にお ける臨界歪量は M n / S が 200を越え る と著 し く 改善さ れ る こ とがわかる。 一方， シ ャ ル ピー衝撃 試験結果では， M 0を添加す る に したが っ て衝撃靭性 は低下す る も のの， C uを添加す る こ と に よ っ て靭性 が改善 さ れ， ま た N i添加に よ っ て も 同様な効果があ る こ とがわ力、る。 The results in Table 2 show that the high-temperature strength was increased by the addition of Nb. Mo and Ni. Ma In addition, the high-temperature strength of the steel with the addition of Mo and C11 is further increased. The results of the continuous high-temperature oxidation test show that the scale release resistance is significantly improved when the Mn content exceeds 0.6% at 900 ° C and 1000 ° C. It can also be seen that the critical strain in the welding high-temperature cracking test is significantly improved when Mn / S exceeds 200. On the other hand, in the results of the Charpy impact test, although the impact toughness decreased with the addition of M0, the toughness was improved by the addition of Cu. It is also clear that the same effect can be obtained by adding Ni.
Figure imgf000017_0001
Figure imgf000017_0001
第 2表 供試鋼の材料特性 Table 2 Material properties of test steel
Figure imgf000018_0001
以上の よ う に本発明 に よ れ は， 高温強度お よ び耐高 温酸化特性に優れた う え， 耐溶接高温割れ に優れ ， し か も フ ェ ラ イ ト 系 ス テ ン レ ス 鋼 の欠点であ る 低温靭性 も 改善 さ れた， 前記の 目 的 に かな っ た フ ユ ラ イ ト 系耐 熱用 ス テ ン レ ス 鋼が得 ら れた。 し たが っ て特 に 今 後 〇 エ ン ジ ン の高 出力 化お よ び高性能化に応え う る 排 ガ ス 系統用 材料， 特 に エ ン ジ ン と コ ン バ一 夕 と の 間 の溶接 造管 さ れ ま た溶接接合部を も つ加工管路部材 と し て， 有用 な新規品を提供す る こ と がで き る 。
Figure imgf000018_0001
As described above, according to the present invention, the steel has excellent high-temperature strength and high-temperature oxidation resistance, excellent resistance to high-temperature cracking at welding, and is also a ferritic stainless steel. Thus, the above-mentioned excellent stainless steel for heat resistance having improved low-temperature toughness, which is a disadvantage of the above, was obtained. Therefore, especially in the future, materials for exhaust gas systems that respond to high output and high performance of the engine, especially between the engine and the converter It is possible to provide a useful new product as a processed pipe member having a welded joint formed by welding.

Claims

請求の範囲 The scope of the claims
( n 重量％ において，  (In n weight%,
C ： 0.03%以下，  C: 0.03% or less,
S i ： 0.1〜 0.8% ,  S i: 0.1 to 0.8%,
M n ： 0. 6— 2.0% ,  M n: 0.6—2.0%,
S ： 0.006%以下，  S: 0.006% or less,
N i ： 4 %以下，  N i: 4% or less,
C r ： 17.0- 25.0 % ,  Cr: 17.0-25.0%,
N b ： 0.2— 0.8% ,  N b: 0.2—0.8%,
0 ： 1.0— 4.5% ,  0: 1.0—4.5%,
C u ： 0. 1— 2.5% ,  Cu: 0.1—2.5%,
N ： 0.03%以下，  N: 0.03% or less,
ただ し， 前記の範囲において， However, in the above range,
M n% / S % の比が 200以上，  The ratio of M n% / S% is 200 or more,
〔 N b〕 = N b % - 8 ( C % + N %  (Nb) = Nb%-8 (C% + N%
の式に従 う 〔 N b〕 が 0.2以上， お よ び  [Nb] is equal to or greater than 0.2, and
N i % + C u%力 4 以下  N i% + Cu% force 4 or less
の関係を満足す る よ う に こ れ らの元素を含有 し， 残 部が F eお よ び製造上の不可避的不純物か らな る 低温 靭性， 溶接性お よ び耐熱性に優れた フ ニ ラ イ ト 系耐熱 用 ス テ ン レ ス鋼。 These elements are contained so as to satisfy the relationship described above, and the balance is Fe and excellent low-temperature toughness, weldability, and heat resistance consisting of unavoidable impurities in production. Nirite based heat-resistant stainless steel.
(2) M 0は 2.5超え〜 4.5%であ る請求の範囲第 1 項 記載の フ ェ ラ イ ト 系耐熱用 ス テ ン レ ス鋼。  (2) The ferritic heat-resistant stainless steel according to claim 1, wherein M0 is more than 2.5 to 4.5%.
(3) 重量％ において， C ： 0.03%以下， (3) In weight percent, C: 0.03% or less,
S i ： 0. 1 ~ 0.8 % ,  S i: 0.1 to 0.8%,
M n ： 0.6〜 2.0 % ,  Mn: 0.6 to 2.0%,
S ： 0.006 %以下，  S: 0.006% or less,
N i ： 4 %以下，  N i: 4% or less,
C r ： 17.0~ 25.0%- N b ： 0.2— 0.8% ,  Cr: 17.0 ~ 25.0%-Nb: 0.2—0.8%,
M o : 1.0— 4.5% ,  M o: 1.0— 4.5%,
C u ： 0. 1 5 % ，  Cu: 0.15%,
N ： 0. 03 %以下，  N: 0.03% or less,
を含有 し， 且つ Containing, and
A 1 ： 0.5%以下，  A 1: 0.5% or less,
T i ： 0. 6%以下，  T i: 0.6% or less,
V ： 0.5 %以下，  V: 0.5% or less,
Z r ： 1.0 %以下，  Zr: 1.0% or less,
W ： 1.5 %以下，  W: 1.5% or less,
B ： 0.01 %以下，  B: 0.01% or less,
REM ： 0. 1 %以下  REM: 0.1% or less
の一種ま た は二種以上を含有 した う え， 前記の範囲 において， One or two or more of the above,
U n% / S %の比が 200以上，  The ratio of U n% / S% is 200 or more,
〔 N b〕 = N b % - 8 ( C % + N % ) の式に従 う 〔 N b〕 が 0.2以上， お よ び According to the formula [Nb] = Nb%-8 (C% + N%), [Nb] is 0.2 or more, and
N i % + C u %力く 4 以下 の関係を満足する よ う に こ れ ら の元素を含有 し， 残部 が F eお よ び製造上の不可避的不純物か ら な る 低温靭 性， 溶接性お よ び耐熱性に優れた フ ェ ラ イ ト 系耐熱用 ス ア ン .レ ス鋼。 N i% + C u% Power 4 or less Fe containing these elements so as to satisfy the relationship described above, with the balance being Fe and excellent low-temperature toughness, weldability, and heat resistance consisting of unavoidable impurities in production. Light and heat-resistant Suanless steel.
(A M 0は 2.5超え〜 4.5%であ る請求の範囲第 3 項 記載の フ ェ ラ イ ト 系耐熱用 ステ ン レ ス鋼。  (The ferritic heat-resistant stainless steel according to claim 3, wherein AMO is more than 2.5 to 4.5%.
(5 当該ステ ン レ ス鋼材料は， エ ン ジ ン と排ガス浄化 機器 と の間の排ガス管路部材を構成す る の に使用 さ れ る請求の範囲第 1 ， 2 , 3 ま た は 4 に記載の フ ェ ラ イ ト 系耐熱用 ス テ ン レ ス鐦。 (5) The stainless steel material may be used to construct an exhaust gas pipe member between an engine and an exhaust gas purification device. Ferrite-based heat-resistant stainless steel に described in.
PCT/JP1991/000344 1990-03-24 1991-03-13 Heat-resistant ferritic stainless steel excellent in low-temperature toughness, weldability and heat resistance WO1991014796A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
EP91906263A EP0478790B1 (en) 1990-03-24 1991-03-13 Heat-resistant ferritic stainless steel excellent in low-temperature toughness, weldability and heat resistance
CA002056362A CA2056362C (en) 1990-03-24 1991-03-13 Heat resisting ferritic stainless steel excellent in low temperature toughness, weldability and heat resistance
KR1019910701642A KR0180206B1 (en) 1990-03-24 1991-03-13 Ferritic heat resistant stainless steel with excellent low temperature toughness, weldability and heat resistance
DE69110816T DE69110816T2 (en) 1990-03-24 1991-03-13 HEAT-RESISTANT FERRITIC STAINLESS STEEL WITH EXCELLENT PROPERTIES FOR TOUGHNESS AT DEEP TEMPERATURES, WELDABILITY AND HEAT RESISTANCE.

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2074785A JP2696584B2 (en) 1990-03-24 1990-03-24 Ferrite heat-resistant stainless steel with excellent low-temperature toughness, weldability and heat resistance
JP2/74785 1990-03-24

Publications (1)

Publication Number Publication Date
WO1991014796A1 true WO1991014796A1 (en) 1991-10-03

Family

ID=13557292

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP1991/000344 WO1991014796A1 (en) 1990-03-24 1991-03-13 Heat-resistant ferritic stainless steel excellent in low-temperature toughness, weldability and heat resistance

Country Status (6)

Country Link
EP (1) EP0478790B1 (en)
JP (1) JP2696584B2 (en)
KR (1) KR0180206B1 (en)
CA (1) CA2056362C (en)
DE (1) DE69110816T2 (en)
WO (1) WO1991014796A1 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112458379A (en) * 2020-10-30 2021-03-09 萍乡德博科技股份有限公司 Material suitable for variable-section nozzle ring disc parts of gasoline engine
CN116460480A (en) * 2023-03-20 2023-07-21 西北有色金属研究院 Special welding wire suitable for titanium-tungsten-niobium-zirconium low-temperature titanium alloy

Families Citing this family (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2085790C (en) * 1991-12-19 2000-03-28 Masao Koike Steel for use in exhaust manifolds of automobiles
EP0593776B1 (en) * 1992-04-09 2001-08-16 Nippon Steel Corporation Ferritic stainless steel with excellent high-temperature salt injury resistance and high-temperature strength
MY118759A (en) * 1995-12-15 2005-01-31 Nisshin Steel Co Ltd Use of a stainless steel as an anti-microbial member in a sanitary environment
FR2746114B1 (en) * 1996-03-15 1998-04-24 PROCESS FOR PRODUCING FERRITIC STAINLESS STEEL HAVING IMPROVED CORROSION RESISTANCE, IN PARTICULAR INTERGRANULAR AND PITCH CORROSION RESISTANCE
KR20000034395A (en) * 1998-11-30 2000-06-26 이구택 Ferritic stainless steel with excellent toughness in welds
KR100605678B1 (en) * 1999-11-08 2006-07-31 주식회사 포스코 Heat-resistant stainless steel with excellent heat resistance
EP1176220B9 (en) 2000-07-25 2004-04-21 JFE Steel Corporation Ferritic stainless steel sheet having superior workability at room temperatures and mechanical characteristics at high temperatures, and method of producing the same
ES2240764T3 (en) * 2001-07-05 2005-10-16 Nisshin Steel Co., Ltd. FERRITIC STAINLESS STEEL FOR EXHAUST FLOW PASSAGE ELEMENT.
CN1308477C (en) * 2003-10-31 2007-04-04 烨联钢铁股份有限公司 Fertilized iron-based stainless steel with good hot workability and antibacterial effect
EP1818421A1 (en) * 2006-02-08 2007-08-15 UGINE & ALZ FRANCE Ferritic, niobium-stabilised 19% chromium stainless steel
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
CN100485077C (en) * 2007-06-13 2009-05-06 陈卫东 Ultrathin alloy material hose and producing method thereof
JP5178157B2 (en) * 2007-11-13 2013-04-10 日新製鋼株式会社 Ferritic stainless steel material for automobile exhaust gas path members
JP5428396B2 (en) * 2008-03-07 2014-02-26 Ｊｆｅスチール株式会社 Ferritic stainless steel with excellent heat resistance and weldability
KR20110018455A (en) * 2008-07-23 2011-02-23 닛폰 스틸 앤드 스미킨 스테인레스 스틸 코포레이션 Ferritic Stainless Steel for Urea Water Tank
JP5462583B2 (en) * 2008-10-24 2014-04-02 新日鐵住金ステンレス株式会社 Ferritic stainless steel sheet for EGR cooler
WO2011013193A1 (en) * 2009-07-27 2011-02-03 日新製鋼株式会社 Ferritic stainless steel for egr cooler and egr cooler
EP2546378A4 (en) 2010-03-11 2017-08-16 Nippon Steel & Sumikin Stainless Steel Corporation Highly oxidation-resistant ferrite stainless steel plate, highly heat-resistant ferrite stainless steel plate, and manufacturing method therefor
JP5609571B2 (en) * 2010-11-11 2014-10-22 Ｊｆｅスチール株式会社 Ferritic stainless steel with excellent oxidation resistance
CN103348023B (en) 2011-02-08 2015-11-25 新日铁住金不锈钢株式会社 The manufacture method of ferrite-group stainless steel hot-rolled steel sheet and manufacture method and ferrite series stainless steel plate
JP5703075B2 (en) * 2011-03-17 2015-04-15 新日鐵住金ステンレス株式会社 Ferritic stainless steel plate with excellent heat resistance
CA2860746C (en) * 2012-01-30 2017-12-19 Jfe Steel Corporation Ferritic stainless steel foil
JP6037882B2 (en) 2012-02-15 2016-12-07 新日鐵住金ステンレス株式会社 Ferritic stainless steel sheet with excellent scale peel resistance and method for producing the same
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
JP5793459B2 (en) 2012-03-30 2015-10-14 新日鐵住金ステンレス株式会社 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
FI125855B (en) * 2012-06-26 2016-03-15 Outokumpu Oy Ferritic stainless steel
EP2966187B1 (en) 2013-03-06 2018-05-02 Nippon Steel & Sumikin Stainless Steel Corporation Ferritic stainless steel sheet having excellent heat resistance
BR112015024500B1 (en) * 2013-03-27 2020-05-12 Nippon Steel & Sumikin Stainless Steel Corporation HOT LAMINATED FERRITIC STAINLESS STEEL SHEET, METHOD FOR THE SAME PRODUCTION, STEEL STRIP, AND ITS USE
CN119411012A (en) * 2016-09-02 2025-02-11 杰富意钢铁株式会社 Ferritic stainless steel
JP6517371B2 (en) * 2017-05-26 2019-05-22 Ｊｆｅスチール株式会社 Ferritic stainless steel
ES2927078T3 (en) 2018-12-21 2022-11-02 Outokumpu Oy ferritic stainless steel

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5785960A (en) * 1980-09-24 1982-05-28 Armco Steel Corp Ferrite type stainless steel having improved rigidity and weldability
JPS62112757A (en) * 1985-11-05 1987-05-23 ユジンヌ・グ−ニヨン・エス・ア− Strip or sheet of ferrite stainless steel
JPH02145752A (en) * 1988-11-28 1990-06-05 Toshiba Corp Ferritic stainless steel

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2701329C2 (en) * 1977-01-14 1983-03-24 Thyssen Edelstahlwerke AG, 4000 Düsseldorf Corrosion-resistant ferritic chrome-molybdenum-nickel steel
JPS53118218A (en) * 1977-03-25 1978-10-16 Nippon Steel Corp Stainless steel use in apparatus for purifying automotive exhaust gas
US4286986A (en) * 1979-08-01 1981-09-01 Allegheny Ludlum Steel Corporation Ferritic stainless steel and processing therefor
US4360381A (en) * 1980-04-11 1982-11-23 Sumitomo Metal Industries, Ltd. Ferritic stainless steel having good corrosion resistance
US4391635A (en) * 1980-09-22 1983-07-05 Kubota, Ltd. High Cr low Ni two-phased cast stainless steel
JP2514367B2 (en) * 1987-06-27 1996-07-10 日新製鋼株式会社 Automotive engine manifold steel
US4834808A (en) * 1987-09-08 1989-05-30 Allegheny Ludlum Corporation Producing a weldable, ferritic stainless steel strip

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5785960A (en) * 1980-09-24 1982-05-28 Armco Steel Corp Ferrite type stainless steel having improved rigidity and weldability
JPS62112757A (en) * 1985-11-05 1987-05-23 ユジンヌ・グ−ニヨン・エス・ア− Strip or sheet of ferrite stainless steel
JPH02145752A (en) * 1988-11-28 1990-06-05 Toshiba Corp Ferritic stainless steel

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See also references of EP0478790A4 *

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112458379A (en) * 2020-10-30 2021-03-09 萍乡德博科技股份有限公司 Material suitable for variable-section nozzle ring disc parts of gasoline engine
CN116460480A (en) * 2023-03-20 2023-07-21 西北有色金属研究院 Special welding wire suitable for titanium-tungsten-niobium-zirconium low-temperature titanium alloy

Also Published As

Publication number Publication date
JP2696584B2 (en) 1998-01-14
CA2056362C (en) 2001-08-28
DE69110816D1 (en) 1995-08-03
CA2056362A1 (en) 1991-09-25
KR0180206B1 (en) 1999-02-18
EP0478790A1 (en) 1992-04-08
JPH03274245A (en) 1991-12-05
EP0478790A4 (en) 1992-08-12
DE69110816T2 (en) 1995-11-30
EP0478790B1 (en) 1995-06-28
KR920702434A (en) 1992-09-04

Similar Documents

Publication Publication Date Title
WO1991014796A1 (en) Heat-resistant ferritic stainless steel excellent in low-temperature toughness, weldability and heat resistance
WO2003004714A1 (en) Ferritic stainless steel for member of exhaust gas flow passage
JP6190873B2 (en) Heat resistant austenitic stainless steel sheet
JP4386144B2 (en) Ferritic stainless steel with excellent heat resistance
JP5387057B2 (en) Ferritic stainless steel with excellent heat resistance and toughness
JP5141296B2 (en) Ferritic stainless steel with excellent high temperature strength and toughness
JP5540637B2 (en) Ferritic stainless steel with excellent heat resistance
JP4185425B2 (en) Ferritic steel sheet with improved formability and high temperature strength, high temperature oxidation resistance and low temperature toughness at the same time
JP4309140B2 (en) Ferritic stainless steel for automotive exhaust system equipment
JP3427502B2 (en) Ferrite stainless steel for automotive exhaust system components
KR100308401B1 (en) Ferritic stainless steel with excellent high temperature oxidation resistance and scale adhesion
JP3219099B2 (en) Ferrite heat-resistant stainless steel with excellent heat resistance, low temperature toughness and weldability
JP2005330501A (en) Austenitic stainless steel for exhaust manifold
JP5428396B2 (en) Ferritic stainless steel with excellent heat resistance and weldability
JP2514367B2 (en) Automotive engine manifold steel
JP2923825B2 (en) Ferritic stainless steel sheet for heat resistance with excellent high-temperature strength and weldability
JPH08239737A (en) Heat resistant austentic stainlss steel excellent in hot workability and sigma-embrittlement resistance
JP2896077B2 (en) Ferrite stainless steel with excellent high-temperature oxidation resistance and scale adhesion
JP3744403B2 (en) Soft Cr-containing steel
JP6665936B2 (en) Ferritic stainless steel
JP2009235572A (en) Ferritic stainless steel having excellent heat resistance and shape-fixability
JP5428397B2 (en) Ferritic stainless steel with excellent heat resistance and workability
JP2879630B2 (en) Ferrite heat-resistant stainless steel with excellent high-temperature salt damage properties
JP2005200746A (en) Ferritic stainless steel for automotive exhaust system parts
JPH11256287A (en) Ferritic stainless steel excellent in high temperature oxidation resistance and scale adhesion

Legal Events

Date Code Title Description
AK Designated states

Kind code of ref document: A1

Designated state(s): CA KR US

AL Designated countries for regional patents

Kind code of ref document: A1

Designated state(s): AT BE CH DE DK ES FR GB GR IT LU NL SE

WWE Wipo information: entry into national phase

Ref document number: 1019910701642

Country of ref document: KR

WWE Wipo information: entry into national phase

Ref document number: 2056362

Country of ref document: CA

Ref document number: 1991906263

Country of ref document: EP

WWP Wipo information: published in national office

Ref document number: 1991906263

Country of ref document: EP

WWG Wipo information: grant in national office

Ref document number: 1991906263

Country of ref document: EP