US20040250923A1 - Method for producing oxidation-resistant high cr ferritic heat resistant steel - Google Patents

Method for producing oxidation-resistant high cr ferritic heat resistant steel Download PDF

Info

Publication number
US20040250923A1
US20040250923A1 US10/501,152 US50115204A US2004250923A1 US 20040250923 A1 US20040250923 A1 US 20040250923A1 US 50115204 A US50115204 A US 50115204A US 2004250923 A1 US2004250923 A1 US 2004250923A1
Authority
US
United States
Prior art keywords
less
steel
ferritic
oxidation
coating film
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.)
Abandoned
Application number
US10/501,152
Other languages
English (en)
Inventor
Takehiko Itagaki
Shiro Torizuka
Hiroyuki Kutsumi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
National Institute for Materials Science
Original Assignee
National Institute for Materials Science
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 National Institute for Materials Science filed Critical National Institute for Materials Science
Assigned to NATIONAL INSTITUTE FOR MATERIALS SCIENCE reassignment NATIONAL INSTITUTE FOR MATERIALS SCIENCE ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ITAGAKI, TAKEHIKO, KUTSUMI, HIROYUKI, TORIZUKA, SHIRO
Publication of US20040250923A1 publication Critical patent/US20040250923A1/en
Abandoned legal-status Critical Current

Links

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
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • 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
    • C21D7/00—Modifying the physical properties of iron or steel by deformation
    • C21D7/13—Modifying the physical properties of iron or steel by deformation by hot working
    • 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
    • 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

Definitions

  • the invention of this application relates to a method for producing ferritic heat-resistant steel for use in boilers of thermal power plants, chemical industry apparatuses, and the like that are operated at high temperatures and under low oxygen partial pressure atmospheres.
  • Heat resistant steel and heat resistant alloys have been used as materials resisting to high temperatures and high pressures at thermal power plants; in the case of using such heat resistant steel and heat resistant alloys under the atmosphere, dense oxide coating film forms on the surface to function as protective layers.
  • the invention of the present application has been made under such circumstances, and the objectives thereof are to overcome the problems of the conventional techniques and to provide a high Cr ferritic heat-resistant steel on which an oxidation-resistant protective coating film is formed even in the presence of high temperature water vapor under low oxygen partial pressure atmospheric condition.
  • the invention of the present application provides, firstly, a steel characterized in that it is a ferritic heat-resistant steel containing 15 mass % or less of Cr, in which at least the region up to 10 ⁇ m defined by surface depth is made of a worked texture composed of extended ferritic grains or superfine texture composed of ferrites 3 ⁇ m or less in grain diameter, and having a protective coating film on the surface.
  • a steel characterized in that the shorter diameter of the extended ferritic grains is 5 ⁇ m or less; and thirdly, it provides a steel characterized in that the shorter diameter of the extended ferritic grains is 3 ⁇ m or less, or the grain diameter of the ferrites is 1 ⁇ m or less.
  • the invention of the present application provides, fourthly, a production method for a steel of one of claims 1 to 3, in which working is applied in the temperature range of from 400 to 800° C. to form a worked texture or superfine ferrite grain texture at least in the region up to 10 ⁇ m defined by surface depth, and pre-oxidation treatment is applied to form a protective coating film; fifthly, it provides a production method in which the working degree on applying working is 0.7 or higher in true strain; and sixthly, a production method in which the pre-oxidation treatment is carried out by holding the steel for 30 to 90 minutes in the temperature range of from 400 to 800° C. under the atmosphere.
  • FIG. 1 is a cross sectional scanning electron microscope (SEM) photograph of an intensively worked part which have been subjected to compression working at a temperature of 500° C., followed by pre-oxidation treatment in the atmosphere at 640° C./1h, an then by water-vapor oxidation at 650° C./100h;
  • SEM scanning electron microscope
  • FIG. 2 is a cross sectional SEM photograph of a weakly worked part which have been subjected to compression working at a temperature of 500° C., followed by pre-oxidation treatment in the atmosphere at 640° C./1h, an then by water-vapor oxidation at 650° C./100h; and
  • FIG. 3 is side cross sectional SEM photograph of an intensively worked part which have been subjected to compression working at a temperature of 500° C., followed by water-vapor oxidation at 650° C./3h without applying pre-oxidation treatment.
  • the invention of the application is most characterized by that the oxidation resistance is improved by applying a specific working and heat-treatment, and not by increasing the composition of chromium (Cr) or silicon (Si), nor by adding elements such as palladium (Pd) or platinum (Pt) and the like. Accordingly, the high Cr ferritic heat-resistant steel obtained by the method for improving the oxidation resistance according to the invention of the application possesses an advantage in that the physical properties and the chemical properties of the initial composition remain without being impaired.
  • the surface layer of the steel material can be modified by applying mechanical treatment such as shot peening and the like, or an oxidation-resistant protective coating film can be formed by applying relatively mild crystal grain refining treatment with large grains about 10 to 50 ⁇ m in particle diameter, however, in high Cr ferritic heat-resistant steel containing 15 mass % or less Cr, such oxidation-resistant protective coating film cannot be formed even if such treatment should be employed.
  • the keys of the invention of the present application are to accumulate strain energy at high levels by applying warm intensive working to the high Cr ferritic heat-resistant steel, or to form fine texture consisting of crystal grains 2 ⁇ m or less in grain diameter.
  • the reason for accumulating strain energy at high levels or for forming fine texture consisting of crystals grains 3 ⁇ m or less in grain diameter is because, the steel material having the strain energy accumulated in high levels easily undergoes recrystallization to form superfine grain texture.
  • the grain boundary area increases to contribute for the diffusion acceleration of chromium (Cr).
  • chromium Cr
  • Cr 2 O 3 chromium oxide
  • thermomechanical treatment such as the rolling or the forging generally employed in the art, it is not possible to highly accumulate the strain energy or to form a fine texture consisting of ferritic crystal grains 3 ⁇ m or less in grain diameter according to the invention of the present application.
  • the working ratio is lower than 70%, the accumulation of the desired strain energy remains insufficient, and the generation of protective coating film and the use thereof cannot be fully expected ever after the pre-oxidation treatment.
  • the morphology of the elongated ferritic grains it is preferred that it has a shorter diameter of 5 ⁇ m or less, and most preferably, it has a shorter diameter of 3 ⁇ m or less; otherwise, the ferritic grains has a grain diameter of 3 ⁇ m or less, and most preferably, they are fine grains 1 ⁇ m or less in grain diameter.
  • the invention of the present application comprises accumulating strain energy at high levels by applying warm intensive working to the high Cr ferritic heat-resistant steel, or forming fine texture consisting of crystal grains 3 ⁇ m or less in grain diameter; however, the protective coating film does not always form at high temperatures in the presence of water vapor by simply accumulating the strain energy by warm intensive working or by forming fine crystal texture. It is necessary to form sequentially thereafter the protective coating film by applying pre-oxidation treatment.
  • the pre-oxidation treatment is preferably carried out under the atmosphere or under an inert gas (rare gas or gaseous nitrogen) atmosphere containing gaseous oxygen, but more practical is to perform the treatment in the atmosphere. Further, the pre-oxidation treatment is preferably performed by heat treatment in the atmosphere at 400 ⁇ 800° C. for about 30 to 90 minutes.
  • chromium (Cr) is oxidized for the first time, and forms Cr 2 O 3 which functions as an oxidation-resistant protective coating film.
  • the grain diameter is 0.8 ⁇ m or less for the sample held at 660° C or lower, and is 1 ⁇ 2 ⁇ m for the sample held at 680 ⁇ 700° C.
  • the invention of the application enables forming an oxidation-resistant protective coating film on the high Cr ferritic heat-resistant steel having a Cr content of 15 mass % or less, on which an oxidation-resistant protective coating film had never been formed, and this widely increases the usage of high Cr ferritic heat-resistant steel. Furthermore, the invention of the application is advantageous in that it utilizes heat treatment, because it does not make any changes on the composition of the high Cr ferric heat-resistant steel. Moreover, since the protective coating film is thin and is tightly adhered, it hardly peels off; it thereby exhibits effect on greatly reducing the risk of causing clogging of the piping due to the peeled off scales, or of wearing the turbine blades.
  • the high Cr ferritic heat-resistant steel of the invention of the application includes those of various compositions containing 15 mass % or less of Cr. For instance, there are included those containing 7 mass % to 15 mass % of Cr.
  • Steel such as the high Cr ferrite heat-resistant steel specified in ASME SA35 P91 or ASME SA 213 T91, are included. These are specified in the invention of the application by the general term “high ferritic (system)” steel.
  • Mod. 9Cr-1Mo steel was subjected to 70% compression working at 500° C., and was cut and polished in such a manner that the fine texture region and the worked texture region should be exposed on the surface. Then, after applying pre-oxidation treatment at 650° C. for 1 h in the atmosphere, the test specimen was oxidized in water vapor at 650° C./100 h.
  • FIG. 1 shows the cross section SEM photograph of the intensively worked part. The formation of the Cr-rich (Cr 2 O 3 ) protective coating film (0.1 ⁇ m or less in thickness) on the surface was observed. Furthermore, the crystal grain diameter of the ferritic grains in the fine texture region under the protective coating film was found to be 1.0 ⁇ m or smaller. Further, the shorter diameter of the elongated ferrite in the worked texture region under the protective coating film was found to be 3 ⁇ m.
  • Mod. 9 Cr-1Mo steel was subjected to pre-oxidation treatment at 680° C. for 1 h in the atmosphere, and was then subjected to water-vapor oxidation at 650° C./100 h.
  • FIG. 2 shows the cross section SEM photograph of the resulting product, but the growth of an Fe-rich double layer scale (about 60 ⁇ m in thickness) due to accelerated oxidation was observed. The average grain diameter of the ferritic grains was 7 ⁇ m.
  • Mod. 9Cr-1Mo steel was subjected to 70% compression working at 500° C. in a manner similar to that of Example 1, and was subjected to water-vapor oxidation at 650° C./3 h thereafter without applying pre-oxidation treatment for observation.
  • FIG. 3 shows the cross section SEM photograph of the intensively worked part. The formation of double layer scale (about 10 ⁇ m in thickness) was observed.
  • the invention of the application enables forming a thin and highly adhesive oxidation-resistant protective coating film, which had been believed impossible, on the high Cr ferritic steel having a Cr content of 15% or less.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
  • Other Surface Treatments For Metallic Materials (AREA)
  • Heat Treatment Of Steel (AREA)
US10/501,152 2002-11-01 2003-11-04 Method for producing oxidation-resistant high cr ferritic heat resistant steel Abandoned US20040250923A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2002-320568 2002-11-01
JP2002320568A JP4253719B2 (ja) 2002-11-01 2002-11-01 耐酸化性高Ｃｒフェライト系耐熱鋼の製造方法
PCT/JP2003/014066 WO2004040031A1 (ja) 2002-11-01 2003-11-04 耐酸化性高Ｃｒフェライト系耐熱鋼の製造方法

Publications (1)

Publication Number Publication Date
US20040250923A1 true US20040250923A1 (en) 2004-12-16

Family

ID=32211858

Family Applications (1)

Application Number Title Priority Date Filing Date
US10/501,152 Abandoned US20040250923A1 (en) 2002-11-01 2003-11-04 Method for producing oxidation-resistant high cr ferritic heat resistant steel

Country Status (8)

Country Link
US (1) US20040250923A1 (ja)
EP (1) EP1557477B1 (ja)
JP (1) JP4253719B2 (ja)
KR (1) KR100619158B1 (ja)
CN (1) CN1329543C (ja)
DE (1) DE60325995D1 (ja)
DK (1) DK1557477T3 (ja)
WO (1) WO2004040031A1 (ja)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9847520B1 (en) * 2012-07-19 2017-12-19 Bloom Energy Corporation Thermal processing of interconnects

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102018217284A1 (de) * 2018-10-10 2020-04-16 Siemens Aktiengesellschaft Verbesserung des Niedertemperatur-Oxidationswiderstands von Chromstahl, Bauteil und Verfahren

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6733601B2 (en) * 2001-01-18 2004-05-11 Jfe Steel Corporation Ferritic stainless steel sheet with excellent workability

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4331474A (en) * 1980-09-24 1982-05-25 Armco Inc. Ferritic stainless steel having toughness and weldability
JPH07268554A (ja) * 1994-03-28 1995-10-17 Nippon Steel Corp 成形加工性および耐熱性の優れた自動車排気系用フェライト系ステンレス鋼板
JPH09143611A (ja) * 1995-11-21 1997-06-03 Nippon Steel Corp 成形性及び疲労特性に優れた耐熱軟化性を有する熱延 高強度鋼板
DE69827729T2 (de) * 1997-09-22 2005-04-28 National Research Institute For Metals Ferritischer,wärmebeständiger Stahl und Verfahren zur Herstellung
KR100536828B1 (ko) * 1997-09-22 2006-02-28 카가쿠기쥬쯔죠 킨조쿠자이료 기쥬쯔켄큐죠 미세페라이트주체조직강과그제조방법
JP4221518B2 (ja) * 1998-08-31 2009-02-12 独立行政法人物質・材料研究機構 フェライト系耐熱鋼
JP4355782B2 (ja) * 1999-02-26 2009-11-04 独立行政法人物質・材料研究機構 耐酸化性の改善されたフェライト系耐熱鋼
JP2001192730A (ja) * 2000-01-11 2001-07-17 Natl Research Inst For Metals Ministry Of Education Culture Sports Science & Technology 高Ｃｒフェライト系耐熱鋼およびその熱処理方法
CN1482648A (zh) * 2000-03-02 2004-03-17 住友金属工业株式会社 彩色显象管荫罩框及框架构件

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6733601B2 (en) * 2001-01-18 2004-05-11 Jfe Steel Corporation Ferritic stainless steel sheet with excellent workability

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9847520B1 (en) * 2012-07-19 2017-12-19 Bloom Energy Corporation Thermal processing of interconnects

Also Published As

Publication number Publication date
DK1557477T3 (da) 2009-05-18
EP1557477B1 (en) 2009-01-21
WO2004040031A1 (ja) 2004-05-13
EP1557477A4 (en) 2006-05-03
CN1692171A (zh) 2005-11-02
JP4253719B2 (ja) 2009-04-15
EP1557477A1 (en) 2005-07-27
KR100619158B1 (ko) 2006-08-31
KR20040089657A (ko) 2004-10-21
DE60325995D1 (de) 2009-03-12
CN1329543C (zh) 2007-08-01
JP2004156075A (ja) 2004-06-03

Similar Documents

Publication Publication Date Title
KR101661019B1 (ko) 태양전지 기판용 강박, 태양전지 기판, 태양전지 및 그들의 제조 방법
JP2007138260A (ja) 酸洗い性に優れたばね用鋼線材
JP2005068453A (ja) 耐高面圧部品及びその製造方法
Birol Response to thermal cycling of plasma nitrided hot work tool steel at elevated temperatures
JP4752635B2 (ja) 軟窒化部品の製造方法
JPH0971853A (ja) 浸炭硬化締結用品およびその製法
US20040250923A1 (en) Method for producing oxidation-resistant high cr ferritic heat resistant steel
Merceron et al. Oxidation behaviour and microstructural evolution of FeCrAl ODS alloys at high temperature
JP2010222696A (ja) 調質熱処理済み鋼帯およびその製造方法
CN1671873A (zh) 耐氢吸收性优异的钛合金材料
JP5295813B2 (ja) 鉄族系合金の窒化処理方法
Yoo et al. A study on nitrogen permeation and tempering heat treatment of AISI type 409L ferritic stainless steel
CN1212024A (zh) 奥氏体不锈钢及其应用
JP5144390B2 (ja) スケール剥離性に優れるＣｒ含有鋼の製造方法
JP2006070313A (ja) 耐遅れ破壊性に優れる表面窒化高強度ステンレス鋼帯及びその製造方法
JP6505415B2 (ja) 加工性と耐食性に優れたＦｅ−Ｃｒ−Ｎｉ系合金材料の表面処理方法
CN114214494A (zh) 一种不锈钢耐腐蚀性能的表面晶界工程处理方法
JPH08158035A (ja) オーステナイト系金属に対する浸炭処理方法およびそれによって得られたオーステナイト系金属製品
JP3064909B2 (ja) 浸炭硬化食器類およびその製法
JP4116383B2 (ja) 弁ばね用またはばね用のオイルテンパー線とその製造方法
JP2004083965A (ja) オーステナイト系ステンレス鋼管の製造方法およびオーステナイト系ステンレス鋼管
Zhang et al. Stress corrosion behavior of low-temperature liquid-nitrided 316 austenitic stainless steel in a sour environment
Drouet et al. Surface engineering of titanium by multi-interstitial diffusion using plasma processing
JP2017031460A (ja) チタン板
KR102290782B1 (ko) 내구성이 우수한 고강도 코팅강판의 제조방법

Legal Events

Date Code Title Description
AS Assignment

Owner name: NATIONAL INSTITUTE FOR MATERIALS SCIENCE, JAPAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:ITAGAKI, TAKEHIKO;TORIZUKA, SHIRO;KUTSUMI, HIROYUKI;REEL/FRAME:015695/0996

Effective date: 20040804

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION