EP3889302A1 - Tôle d'acier chrome-molybdène présentant une excellente résistance au fluage et son procédé de fabrication - Google Patents

Tôle d'acier chrome-molybdène présentant une excellente résistance au fluage et son procédé de fabrication Download PDF

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EP3889302A1
EP3889302A1 EP19888281.3A EP19888281A EP3889302A1 EP 3889302 A1 EP3889302 A1 EP 3889302A1 EP 19888281 A EP19888281 A EP 19888281A EP 3889302 A1 EP3889302 A1 EP 3889302A1
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less
steel plate
exclusive
chromium
excellent creep
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EP3889302A4 (fr
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Hyun-Je SUNG
Dae-Woo Kim
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Posco Holdings Inc
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Posco Co Ltd
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    • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
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    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/008—Martensite

Definitions

  • the present disclosure relates to manufacturing of a chromium-molybdenum steel plate having excellent creep properties, and more particularly, to a chromium-molybdenum steel plate which may have an excellent creep strength by forming only fine carbonitrides in the inside and the grain boundary of a martensite matrix of a composed phase of a steel material to interrupt dislocation movement at a high temperature and secure stability of sub-crystal grains, and a method for manufacturing the same.
  • an austenite stainless steel contains a large amount of high-priced alloying elements, it is expensive and its use is limited due to poor physical properties (low thermal conductivity and high coefficient of thermal expansion) and a difficulty in manufacture of large parts.
  • a chromium steel is often used due to its excellent creep strength, weldability, corrosion resistance, oxidation resistance, and the like.
  • An aspect of the present disclosure is to provide a chromium-molybdenum steel plate having excellent creep properties by completely suppressing formation of coarse precipitates such as (Fe,Cr) 23 C 6 carbides and forming only fine carbonitrides without extremely lowering a carbon content, unlike the conventional technologies described above, using alloy design and heat treatment, and a method for manufacturing the same.
  • a chromium-molybdenum steel plate having excellent creep strength includes, by weight: 0.11 to 0.15% of C, 0.10% or less (exclusive of 0%) of Si, 0.3 to 0.6% of Mn, 0.010% or less (exclusive of 0%) of S, 0.015% or less (exclusive of 0%) of P, 2.0 to 2.5% of Cr, 0.9 to 1.1% of Mo, 0.65 to 1.0% of V, 0.25% or less (exclusive of 0%) of Ni, 0.20% or less (exclusive of 0%) of Cu, 0.07% or less (exclusive of 0%) of Nb, 0.03% or less (exclusive of 0%) of Ti, 0.015% or less (exclusive of 0%) of N, 0.025% or less (exclusive of 0%) of Al, and 0.002% or less (exclusive of 0%) of B, with a balance of Fe and unavoidable impurities.
  • the steel plate may have a microstructure including tempered martensite.
  • the number of precipitates having a diameter of 200 nm or more including (Fe,Cr) 23 C 6 is in a range of one/ ⁇ m 2 or less in the microstructure of the steel plate.
  • the number of precipitates having a diameter of 20 nm or less is in a range of 20/ ⁇ m 2 or more in the microstructure of the steel plate.
  • the precipitates having a diameter of 20 nm or less may be (V,Mo,Nb,Ti) (C,N).
  • a method for manufacturing a steel plate includes:
  • the chromium-molybdenum steel plate having excellent creep properties of the present disclosure having the configuration described above may have a longer creep life than an ASTM A387 Grade 91 steel containing chromium in a large amount of 9 wt%, with an excellent creep life at a high temperature, by quenching and tempering.
  • the present inventors repeated studies and experiments, and as a result, confirmed that by optimizing an amount of vanadium added to a thermal resistant chromium steel alloy containing 2.0 to 2.5% of Cr and also properly controlling a tempering temperature, a thermal resistant chromium steel having excellent creep properties may be obtained, thereby suggesting the present disclosure.
  • the chromium-molybdenum steel plate having excellent creep strength of the present disclosure includes, by weight: 0.11 to 0.15% of C, 0.10% or less (exclusive of 0%) of Si, 0.3 to 0.6% of Mn, 0.010% or less (exclusive of 0%) of S, 0.015% or less (exclusive of 0%) of P, 2.0 to 2.5% of Cr, 0.9 to 1.1% of Mo, 0.65 to 1.0% of V, 0.25% or less (exclusive of 0%) of Ni, 0.20% or less (exclusive of 0%) of Cu, 0.07% or less (exclusive of 0%) of Nb, 0.03% or less (exclusive of 0%) of Ti, 0.015% or less (exclusive of 0%) of N, 0.025% or less (exclusive of 0%) of Al, and 0.002% or less (exclusive of 0%) of B, with a balance of Fe and unavoidable impurities.
  • Carbon is an element for austenite stabilization, which may adjust an Ae3 temperature and a martensite formation initiation temperature depending on the content and is very effective for applying asymmetric distortion as an interstitial element to a lattice structure of a martensite phase to secure high strength.
  • a carbon content in the steel is more than 0.15%, carbides are excessively formed and weldability is greatly deteriorated.
  • the carbon content it is preferable to limit the carbon content to a range of 0.11 to 0.15%, more preferably to a range of 0.11 to 0.14% in the present disclosure.
  • Silicon is added as a deoxidizer during casting as well as for strengthening of solid solution.
  • silicon serves to suppress carbide formation.
  • a silicon content it is preferable to limit a silicon content to 0.10% or less, more preferably to a range of 0.005 to 0.08% in the present disclosure.
  • Manganese is an element for austenite stabilization, which greatly increases hardenability of a steel to allow a hard phase such as martensite to be formed.
  • manganese reacts with sulfur so that MnS is precipitated, which is advantageous for preventing cracks at a high temperature by sulfur segregation.
  • an austenite stability degree is excessively increased.
  • the manganese content it is preferable to limit the manganese content to a range of 0.3 to 0.6%, more preferably to a range of 0.35 to 0.55% in the present disclosure.
  • Sulfur is an impurity element and when the content is more than 0.010%, ductility and weldability of a steel are deteriorated.
  • a sulfur content 0.010% or less.
  • Phosphorus (P) 0.015% or less (exclusive of 0%)
  • Phosphorus is an element having a solid solution strengthening effect, but an impurity element like sulfur, when the content is more than 0.015%, a steel has brittleness and decreased weldability.
  • a phosphorus content 0.015% or less.
  • Chromium is a ferrite stabilization element and an element increasing hardenability, and adjusts an Ae3 temperature and a delta ferrite forming temperature range depending on the amount.
  • chromium reacts with oxygen to form a dense and stable protective film of Cr 2 O 3 to increase oxidation resistance and corrosion resistance at a high temperature, but increases a delta ferrite forming temperature range.
  • delta ferrite may be formed, and remains even after heat treatment to adversely affect steel characteristics.
  • the chromium content it is preferable to limit the chromium content to a range of 2.0 to 2.5%, more preferably to a range of 2.1 to 2.4% in the present disclosure.
  • Mo Molybdenum
  • Molybdenum is known as an element which increases hardenability and stabilizes ferrite. Molybdenum increases a creep life at a high temperature by strong solid solution strengthening, participates as a metal element forming M(C,N) carbonitrides to stabilize carbonitrides, and greatly reduces a coarsening speed. However, when a molybdenum content is increased, a delta ferrite forming temperature range may be widened and delta ferrite may be formed and remain in a process of casting a steel. Remaining delta ferrite adversely affects steel characteristics.
  • the molybdenum content it is preferable to limit the molybdenum content to a range of 0.9 to 1.1%, more preferably to a range of 0.95 to 1.05%.
  • Vanadium is one of elements forming M(C,N) carbonitrides, and when a vanadium content is increased, (Fe,Cr) 23 C 6 carbide formation driving force is decreased, resulting in complete suppression of (Fe,Cr) 23 C 6 carbide formation.
  • (Fe,Cr) 23 C 6 carbide formation driving force is decreased, resulting in complete suppression of (Fe,Cr) 23 C 6 carbide formation.
  • 0.65% or more of a vanadium alloy is needed.
  • the vanadium content is more than 1.0%, there is a difficulty in a production process of materials.
  • the vanadium content it is preferable to limit the vanadium content to a range of 0.65 to 1.0%, more preferably to a range of 0.67 to 0.98%.
  • Nickel is an element for improving toughness of a steel and is added for increasing steel strength without deterioration of toughness at a low temperature. When nickel is added at the content of more than 0.25%, a price increase due to nickel addition is caused.
  • the nickel content it is preferable to limit the nickel content to a range of 0.25% or less, more preferably to a range of 0.005 to 0.24%.
  • Copper is an element for improving hardenability of materials and is added so that a steel plate has a homogeneous structure after heat treatment.
  • the amount added is more than 0.20%, a possibility of crack occurrence for steel plate may be increased.
  • a copper content it is preferable to limit a copper content to 0.20% or less, more preferably to a range of 0.005 to 0.18%.
  • Niobium is one of elements forming M(C,N) carbonitrides. In addition, it is solid-solubilized when reheating a slab and suppresses austenite crystal grain growth during hot rolling, and then is precipitated to improve steel strength. However, when niobium is excessively added at more than 0.07%, weldability may be deteriorated and crystal grains may be fined than necessary.
  • a niobium content it is preferable to limit a niobium content to 0.07% or less, more preferably to a range of 0.005 to 0.06%.
  • Titanium is also an element effective for suppressing austenite crystal grain growth in a TiN form. However, when titanium is added at more than 0.03%, coarse Ti-based precipitates are formed and there is a difficulty in welding of materials.
  • a titanium content it is preferable to limit a titanium content to 0.03% or less, more preferably to a range of 0.005 to 0.025%.
  • N 0.015% which is a range allowable in a manufacturing process.
  • Nitrogen is known as an austenite stabilization element, and stability at a high temperature is greatly increased when forming M(C,N) carbonitrides as compared with simple MC carbides, thereby effectively increasing creep strength of a steel material.
  • nitrogen is bonded to boron to form BN, thereby increasing a risk of defect occurrence.
  • a nitrogen content 0.015% or less.
  • Aluminum enlarges a ferrite area, and is added as a deoxidizer during casting. Since in a chromium steel, other ferrite stabilization elements are alloyed much, when an aluminum content is increased, an Ae3 temperature may be excessively raised. In addition, when the amount added is more than 0.025%, an oxide-based inclusion is formed in a large amount to deteriorate the physical properties of a material.
  • the aluminum content it is preferable to limit the aluminum content to 0.025% or less, more preferably to a range of 0.005 to 0.025%.
  • Boron is a ferrite stabilization element and contributes much to a hardenability increase only with a little amount. In addition, it is easily segregated in a crystal grain boundary to give a crystal grain boundary strengthening effect. However, when boron is added at more than 0.002%, BN may be formed, which may adversely affect the mechanical properties of materials.
  • a boron content it is preferable to limit a boron content to 0.002% or less.
  • the steel plate of the present disclosure includes a tempered martensite structure as the matrix microstructure.
  • a tempered bainite structure may be partly included depending on heat treatment conditions.
  • the number of precipitates having a diameter of 200 nm or more including (Fe,Cr) 23 C 6 is in a range of one/ ⁇ m 2 or less in the steel plate microstructure of the present disclosure.
  • the number of precipitates having a diameter of 200 nm or more is more than one/ ⁇ m 2 , deteriorated creep properties may be caused by coarse carbides.
  • the number of precipitates having a diameter of 20 nm or less is in a range of 20/ ⁇ m 2 or more in the steel plate microstructure of the present disclosure.
  • the number of precipitates having a diameter of 20 nm or less is less than 20/ ⁇ m 2 , a distance between fine carbonitrides is significantly increased. Therefore, since dislocation movement at a high temperature and movement of sub-crystal grains are not effectively prevented, an effect of improving creep properties may not be large.
  • the precipitates having a diameter of 20 nm or less in the present disclosure may include (V,Mo,Nb,Ti)(C,N).
  • the method for manufacturing a precipitation hardening type chromium-molybdenum steel plate having excellent creep strength of the present disclosure includes: hot-rolling a steel slab having the composition described above so that a finish rolling temperature is equivalent to or higher than Ar3 to manufacture a hot rolled steel plate, and then cooling the hot rolled steel plate; reheating the cooled hot rolled steel plate in a temperature range of 900 to 1200°C for 1t to 3t minutes [t (mm) is a thickness of the hot rolled steel plate] to austenitize the steel plate; quenching the austenitized hot rolled steel plate to room temperature; and tempering the quenched hot rolled steel plate in a temperature range of 675 to 800°C for 30 minutes to 120 minutes.
  • a steel slab having the composition component described above is hot-rolled so that a finish rolling temperature is equivalent to or higher than Ar3 to obtain a hot rolled steel plate.
  • the reason for performing hot rolling in an austenite single phase region is to increase uniformity of a structure.
  • the hot rolled steel plate manufactured was cooled to room temperature.
  • the cooled hot rolled steel plate is reheated to austenitize the steel plate.
  • a reheating temperature range is 900 to 1200°C and a reheating time is in a range of 1t minute to 3t minutes depending on a thickness t (mm) of the hot rolled steel plate.
  • the reheating temperature is lower than 900°C, it is difficult to properly redissolve undesired carbides formed in a process of cooling after hot rolling.
  • the reheating temperature is higher than 1200°C, the characteristics may be deteriorated due to crystal grain coarsening.
  • the reheating time is in a range of 1t to 3t, in which the thickness of the hot rolled steel plate is t (mm).
  • t the thickness of the hot rolled steel plate
  • reheating may be performed for 20 to 60 minutes.
  • the reheating time is less than 1t minute, it is difficult to properly redissolve undesired carbides formed in a process of cooling after hot rolling, but when the reheating time is more than 3t minutes, the characteristics may be deteriorated due to crystal grain coarsening.
  • the hot rolled steel plate austenitized by the reheating is quenched to be cooled down to room temperature, thereby obtaining a martensite structure.
  • care should be taken so that ferrite and pearlite structures are not formed to greatly decrease matrix strength.
  • the quenched hot rolled steel plate is tempered.
  • a tempering temperature is 675 to 800°C
  • a tempering time is 30 minutes to 120 minutes, and then air cooling is performed.
  • tempering temperature When the tempering temperature is lower than 675°C, precipitation of fine carbonitrides may not be induced in time due to the low temperature. However, when the tempering temperature is higher than 800°C, tempering causes softening of materials to greatly decrease a creep life.
  • the tempering temperature is controlled to a range of 700 to 780°C.
  • Hot rolled steel plates having alloy compositions of the following Table 1 and a thickness of 20 mm were prepared. Then, the hot rolled steel plate was reheated at 1000°C for 1 hour and quenched to cool down to room temperature. Subsequently, the cooled steel plate was tempered at 730°C for 1 hour and then air-cooled to room temperature to manufacture a Cr-Mo alloy steel. Meanwhile, in the following Table 1, steel type 1 is a composition of ASTM A542D steel and steel types 2 to 4 are steel types satisfying the steel composition components of the present disclosure.
  • the chromium-molybdenum steel plate of the present disclosure had a better creep life than the ASTM A387 Grade 91 steel material including 9 wt% of Cr.
  • steel types 2 to 4 satisfying the steel composition components of the present disclosure had better creep properties than steel type 1 which did not satisfy the steel composition components of the present disclosure.
  • FIG. 6 shows that when a vanadium content is increased, (Fe,Cr) 23 C 6 carbide formation driving force is decreased, resulting in complete suppression of (Fe,Cr) 23 C 6 carbide formation.
  • a vanadium content is increased, (Fe,Cr) 23 C 6 carbide formation driving force is decreased, resulting in complete suppression of (Fe,Cr) 23 C 6 carbide formation.
  • 0.65 wt% or more vanadium alloying is needed, when considering the tempering temperature range of 675 to 800°C and the creep temperature mentioned in the present disclosure. That is, it is seen that since steel types 2 to 4 of the present disclosure all included 0.65 wt% or more vanadium unlike steel type 1, (Fe,Cr) 23 C 6 carbide formation was able to be completely suppressed.
  • FIG. 7 is a scanning microscope photograph illustrating the results of observing the microstructure of a steel plate which was reheated at 1000°C for 1 hour, quenched to be cooled down to room temperature, and tempered at 730°C for 1 hour, and steel types 2 to 4 all showed fine carbonitride precipitation along sub-crystal grain boundary. It is seen that the carbonitrides as such effectively interrupt dislocation movement at a high temperature and also effectively prevent movement of sub-crystal grains to secure the stability, thereby greatly improving creep properties as compared with the conventional chromium steel. However, it is seen that steel type 1 formed coarse (Fe,Cr) 23 C 6 carbides and the creep properties were not good as compared with steel types 2 to 4.

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EP19888281.3A 2018-11-29 2019-11-29 Tôle d'acier chrome-molybdène présentant une excellente résistance au fluage et son procédé de fabrication Pending EP3889302A4 (fr)

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PCT/KR2019/016694 WO2020111857A1 (fr) 2018-11-29 2019-11-29 Tôle d'acier chrome-molybdène présentant une excellente résistance au fluage et son procédé de fabrication

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KR102415765B1 (ko) * 2020-08-27 2022-07-01 주식회사 포스코 크리프 강도와 충격 인성이 우수한 크롬강 및 이의 제조방법
CN117385127A (zh) * 2023-09-11 2024-01-12 舞阳钢铁有限责任公司 一种提高大厚度Cr-Mo钢高温性能的方法

Family Cites Families (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH079027B2 (ja) * 1988-09-30 1995-02-01 住友金属工業株式会社 高温用低合金鋼の成形加工方法
JPH062927B2 (ja) * 1989-02-20 1994-01-12 住友金属工業株式会社 耐食、耐酸化性に優れた高強度低合金鋼
JPH0742546B2 (ja) * 1989-08-16 1995-05-10 住友金属工業株式会社 熱間スラブの幅サイジング用金型
JP3237137B2 (ja) * 1991-08-12 2001-12-10 住友金属工業株式会社 溶接熱影響部の強度低下の小さい高クロムフェライト耐熱鋼
JPH101739A (ja) * 1996-06-11 1998-01-06 Nkk Corp 高温強度と溶接性に優れた低合金耐熱鋼およびその製造方法
JP3283768B2 (ja) * 1996-10-28 2002-05-20 株式会社神戸製鋼所 高強度Ｃｒ−Ｍｏ鋼のＴＩＧ溶接金属及びＴＩＧ溶接方法
JP3565155B2 (ja) * 2000-01-13 2004-09-15 住友金属工業株式会社 高強度低合金耐熱鋼
JP3525843B2 (ja) * 2000-02-09 2004-05-10 住友金属工業株式会社 高強度低合金耐熱鋼
US6641780B2 (en) * 2001-11-30 2003-11-04 Ati Properties Inc. Ferritic stainless steel having high temperature creep resistance
JP4009124B2 (ja) * 2002-03-28 2007-11-14 新日本製鐵株式会社 長時間クリープ特性に優れた高強度低Ｃｒフェライト系ボイラ用鋼管およびその製造方法
JP4074555B2 (ja) * 2003-06-03 2008-04-09 新日本製鐵株式会社 クリープ特性に優れた高強度低合金ボイラ用鋼の製造方法
EP3696292B1 (fr) * 2007-10-25 2024-03-13 JFE Steel Corporation Tôle d'acier galvanisée avec une résistance élevée à la traction ayant une excellente aptitude à la déformation et propriétés anti-écrasement et procédé de son production
KR101140651B1 (ko) * 2010-01-07 2012-05-03 한국수력원자력 주식회사 크리프 저항성이 우수한 고크롬 페라이트/마르텐사이트 강 및 이의 제조방법
DE102012011161B4 (de) * 2012-06-05 2014-06-18 Outokumpu Vdm Gmbh Nickel-Chrom-Aluminium-Legierung mit guter Verarbeitbarkeit, Kriechfestigkeit und Korrosionsbeständigkeit
KR101568523B1 (ko) * 2013-12-24 2015-11-11 주식회사 포스코 소려 취화 저항성이 우수한 압력용기용 강판 및 그 제조 방법
KR20150104348A (ko) * 2014-03-05 2015-09-15 한국원자력연구원 크리프 저항성이 향상된 페라이트/마르텐사이트계 산화물분산강화 강 및 이의 제조방법
WO2015174530A1 (fr) * 2014-05-15 2015-11-19 新日鐵住金株式会社 Élément de plaque d'acier laminée à chaud
KR102326684B1 (ko) * 2019-09-17 2021-11-17 주식회사 포스코 크리프 강도와 고온 연성이 우수한 크롬강판 및 그 제조방법

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JP2022509978A (ja) 2022-01-25
KR20200065150A (ko) 2020-06-09
KR102142782B1 (ko) 2020-08-10
WO2020111857A1 (fr) 2020-06-04
JP7232910B2 (ja) 2023-03-03
CN113166901A (zh) 2021-07-23
US20220025477A1 (en) 2022-01-27
CN113166901B (zh) 2023-02-17

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