EP0566814A1 - Superduplex stainless steel having high corrosion resistance and high yield strength in the solution annealed condition - Google Patents

Superduplex stainless steel having high corrosion resistance and high yield strength in the solution annealed condition Download PDF

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Publication number
EP0566814A1
EP0566814A1 EP92830586A EP92830586A EP0566814A1 EP 0566814 A1 EP0566814 A1 EP 0566814A1 EP 92830586 A EP92830586 A EP 92830586A EP 92830586 A EP92830586 A EP 92830586A EP 0566814 A1 EP0566814 A1 EP 0566814A1
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EP
European Patent Office
Prior art keywords
max
corrosion resistance
stainless steel
yield strength
solution annealed
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EP92830586A
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German (de)
French (fr)
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EP0566814B1 (en
Inventor
Luca Foroni
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FORONI SpA
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FORONI SpA
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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
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • 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
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper

Definitions

  • Austenitic/Ferritic stainless steels presently on the market are those reported in the ASTM A790 specification with the addition of the Zeron 100, equivalent to UNS S32760, which is not yet included in the ASTM specification.
  • the steel grades which are mainly requested for the oil field applications are the UNS S32750 and UNS S32760.
  • the A.O.D. refining allows a deep deoxydation and desulphurization of the steel as well as to reach the required chemical composition in a repeatable way.
  • the analytical balancing of the alloying elements Cr, Mo, W, Cu and N is very important for obtaining the mechanical properties and the corrosion resistance on hot forged and/or rolled products in the solution annealed condition.
  • Our invention has taken advantage of the combined action of Mo, W, Cu, N which allows to reach a yield strength value higher than 620 MPa (90,000 PSI) as well as a generalized resistance to the stress corrosion, to the pitting and crevice corrosions.
  • the optimized chemical composition is the following : (weight in percent) C 0.025 max Mn 0.80 max Si 0.80 max Cr 24 - 26 Ni 6.5 - 8.0 Mo 3.0 - 4.0 S 0.002 max P 0.025 max Cu 1.2 - 2.0 W 0.80 - 1.2 N 0.23 - 0.33 Fe balance
  • a B C weight loss (g/m2) 0.049 0.070 0.76 N° of pitting/m2 0 0 270 Max pit depth (micron) 0 0 100 Critical Pitting Temp.(°C) 80 60 50 2.3 Corrosion resistance in 5% Na Cl at PH 4 - 6 at 600 mV : A B C CPT (°C) 80 72 63 2.4 Crevice corrosion resistance (ASTM G78 modified) 100 days .

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Steel (AREA)
  • Heat Treatment Of Articles (AREA)
  • Treatment Of Steel In Its Molten State (AREA)

Abstract

The steel, object of our invention is highly resistant to stress corrosion in acid and alkaline environment, and has furthermore high pitting and crevice corrosion resistance. This steel has a very high yield strength, even in the solution annealed condition.
The steel consists of: (in weight percent)
C   0.025 max
Mn   0.80 max
Si   0.80 max
Cr   24 - 26
Ni   6.5 - 8.0
Mo   3.0 - 4.0
Cu   1.2 - 2.0
W   0.8 - 1.2
N   0.23 - 0.33
S   0.002 max
P   0.025 max
Fe   balance
with the proviso: Pitting Index = Cr + 3.3 Mo + 16N > 42

Description

  • The Austenitic/Ferritic stainless steels presently on the market are those reported in the ASTM A790 specification with the addition of the Zeron 100, equivalent to UNS S32760, which is not yet included in the ASTM specification.
  • The steel grades which are mainly requested for the oil field applications are the UNS S32750 and UNS S32760.
  • There are however many other kind of steels which can be included in the same class and which are listed and described in the following publications :
    • Encl. 1 -
    Superduplex Stainless Steel : Structure and Properties. by J. Charles
    Encl. 2 -
    Superduplex Stainless Steel : Structure and Properties. by J. Charles
    Encl. 3 -
    The Corrosion Resistance of Duplex Stainless Steel. by S. Bernhardsson
    The invention concerns the production of austenitic-ferritic stainless steel of the superduplex class, manufactured by electrical arc melting and A.O.D. refining.
  • The A.O.D. refining allows a deep deoxydation and desulphurization of the steel as well as to reach the required chemical composition in a repeatable way.
  • The analytical balancing of the alloying elements Cr, Mo, W, Cu and N is very important for obtaining the mechanical properties and the corrosion resistance on hot forged and/or rolled products in the solution annealed condition.
  • Our invention has taken advantage of the combined action of Mo, W, Cu, N which allows to reach a yield strength value higher than 620 MPa (90,000 PSI) as well as a generalized resistance to the stress corrosion, to the pitting and crevice corrosions.
  • The optimized chemical composition is the following :
    (weight in percent)
    C 0.025 max
    Mn 0.80 max
    Si 0.80 max
    Cr 24 - 26
    Ni 6.5 - 8.0
    Mo 3.0 - 4.0
    S 0.002 max
    P 0.025 max
    Cu 1.2 - 2.0
    W 0.80 - 1.2
    N 0.23 - 0.33
    Fe balance
  • The ferrite on the product solution annealed at the temperature of 1070 - 1100°C is 40 - 55%

    Pitting index = Cr + 3.3 Mo + 16 N > 42
    Figure imgb0001


    1. Mechanical characteristics of the product solution annealed at 1080 °C :
    Figure imgb0002

    2. Comparisons with other steels of the same class on the basis of the corrosion resistance :
    2.1 Chemical analysis of steel (A = Steel subject of the invention)
    Cr Ni Mo Cu W N
    A) 25.5 7.4 3.9 1.7 0.9 0.27
    B) 25.5 7.1 3.6 0.7 0.7 0.26
    C) 25.4 7.0 3.6 0.2 --- 0.28

    2.2 Pitting corrosion resistance (ASTM G48) at 50°C - 24 h.
    A B C
    weight loss (g/m²) 0.049 0.070 0.76
    N° of pitting/m² 0 0 270
    Max pit depth (micron) 0 0 100
    Critical Pitting Temp.(°C) 80 60 50

    2.3 Corrosion resistance in 5% Na Cl at PH = 4 - 6 at 600 mV :
    A B C
    CPT (°C) 80 72 63

    2.4 Crevice corrosion resistance (ASTM G78 modified) 100 days .
    • Environment :
    Aerated sea water containing 20,000 ppm cloride plus 2 ppm residual chlorine with occasional shock dosing up to 10 ppm chlorine ar 35°C
    A B C
    N° of crevice (min/max) Absent 1 / 3 Traces

    2.5 Sulfide Stress Cracking Resistance of the steel object of the invention (NACE TM-01-77) at 80°C - 760 h :
    Applied load = 550 MPa no cracking
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Claims (8)

  1. Chemical composition (in percent by weight ) : C 0.025 max Mn 0.80 max Si 0.80 max Cr 24 - 26 Ni 6.5 - 8.0 Mo 3.0 - 4.0 S 0.002 max P 0.025 max Cu 1.2 - 2.0 W 0.8 - 1.2 N 0.23 - 0.33 Fe balance
    Pitting Index = Cr + 3.3 Mo + 16 N > 42
    Figure imgb0085

    Balanced chemical composition to obtain after solution heat treatment at 1070-1100°C an alfa Ferrite of 40 - 60%.
  2. Alloy according to claim 1, characterized in that the content of C is 0.01 - 0.02%.
  3. Alloy according to claim 1, characterized in that the content of Si is 0.35 - 0.60%.
  4. Alloy according to claim 1, characterized in that the content of Ni is 7.0 - 7.5%.
  5. Alloy according to claim 1, characterized in that the content of Mo is 3.7 - 4.0%
  6. Alloy according to claim 1, characterized in that the content of Cu is 1.6- 1.9%.
  7. Alloy according to claim 1, characterized in that the content of W is 0.9- 1.1%.
  8. Alloy accorgind to claim 1, characterized in that the content of N is 0.25- 0.30%.
EP92830586A 1992-04-24 1992-10-26 Superduplex stainless steel having high corrosion resistance and high yield strength in the solution annealed condition Revoked EP0566814B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
ITRM920309 1992-04-24
ITRM920309A IT1257695B (en) 1992-04-24 1992-04-24 AUSTENO-FERRITIC STEEL WITH HIGH CORROSION RESISTANCE AND HIGH STRENGTH AT THE SOLUBIZED STATE.

Publications (2)

Publication Number Publication Date
EP0566814A1 true EP0566814A1 (en) 1993-10-27
EP0566814B1 EP0566814B1 (en) 1997-09-03

Family

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Family Applications (1)

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EP92830586A Revoked EP0566814B1 (en) 1992-04-24 1992-10-26 Superduplex stainless steel having high corrosion resistance and high yield strength in the solution annealed condition

Country Status (4)

Country Link
EP (1) EP0566814B1 (en)
AT (1) ATE157710T1 (en)
DE (1) DE69222027D1 (en)
IT (1) IT1257695B (en)

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0594935A1 (en) 1992-10-27 1994-05-04 DALMINE S.p.A. Highly mechanical and corrosion resistant stainless steel and relevant treatment process
EP0649913A1 (en) * 1993-10-21 1995-04-26 Creusot-Loire Industrie High strength stainless austenitic steel with high structural stability and its uses
EP0683241A3 (en) * 1994-05-21 1996-05-08 Park Yong S Duplex stainless steel with high corrosion resistance.
EP0757112A1 (en) * 1994-04-05 1997-02-05 Sumitomo Metal Industries, Ltd. Two-phase stainless steel
EP0692547B1 (en) * 1994-07-11 2001-10-04 Metso Powdermet Oy Roll manufacture
US8710405B2 (en) * 2005-04-15 2014-04-29 Nippon Steel & Sumikin Stainless Steel Corporation Austenitic stainless steel welding wire and welding structure
CN103966522A (en) * 2013-01-25 2014-08-06 精工电子有限公司 Two-phase Stainless Steel, Method Of Manufacturing The Same, And Diaphragm, Pressure Sensor, And Diaphragm Valve Using Two-phase Stainless Steel
JP2019505677A (en) * 2015-12-23 2019-02-28 グッドウィン ピーエルシーＧｏｏｄｗｉｎ Ｐｌｃ Steel, welding consumables, cast or forged or stretched products, welding methods, welded products, and heat treatment methods
CN111197144A (en) * 2020-02-21 2020-05-26 青岛三庆金属有限公司 High-temperature-resistant stainless steel composition for food heating container
WO2020158111A1 (en) * 2019-01-30 2020-08-06 Ｊｆｅスチール株式会社 Duplex stainless steel, seamless steel pipe, and production method for duplex stainless steel

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10357653A1 (en) * 2003-12-10 2005-07-07 Abb Research Ltd. Ship propulsion system, e.g. for container ships and liquid gas tankers, has a propeller at a motor housing and carrier arm attached to the hull of a non-corroding metal alloy

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2160221A (en) * 1984-06-13 1985-12-18 Nippon Kokan Kk Two phase stainless steel having improved impact characteristic
GB2203680A (en) * 1987-04-21 1988-10-26 Nippon Yakin Kogyo Co Ltd Direct production of stainless steel strip having excellent superplasticity and surface properties
US4816085A (en) * 1987-08-14 1989-03-28 Haynes International, Inc. Tough weldable duplex stainless steel wire
EP0360143A1 (en) * 1988-09-13 1990-03-28 Carondelet Foundry Company Corrosion resistant alloy

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2160221A (en) * 1984-06-13 1985-12-18 Nippon Kokan Kk Two phase stainless steel having improved impact characteristic
GB2203680A (en) * 1987-04-21 1988-10-26 Nippon Yakin Kogyo Co Ltd Direct production of stainless steel strip having excellent superplasticity and surface properties
US4816085A (en) * 1987-08-14 1989-03-28 Haynes International, Inc. Tough weldable duplex stainless steel wire
EP0360143A1 (en) * 1988-09-13 1990-03-28 Carondelet Foundry Company Corrosion resistant alloy

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0594935A1 (en) 1992-10-27 1994-05-04 DALMINE S.p.A. Highly mechanical and corrosion resistant stainless steel and relevant treatment process
US5352406A (en) * 1992-10-27 1994-10-04 Centro Sviluppo Materiali S.P.A. Highly mechanical and corrosion resistant stainless steel and relevant treatment process
US5494636A (en) * 1993-01-21 1996-02-27 Creusot-Loire Industrie Austenitic stainless steel having high properties
EP0649913A1 (en) * 1993-10-21 1995-04-26 Creusot-Loire Industrie High strength stainless austenitic steel with high structural stability and its uses
FR2711674A1 (en) * 1993-10-21 1995-05-05 Creusot Loire Austenitic stainless steel with high characteristics having high structural stability and uses.
US5849111A (en) * 1994-04-05 1998-12-15 Sumitomo Metal Industries, Ltd. Duplex stainless steel
EP0757112A1 (en) * 1994-04-05 1997-02-05 Sumitomo Metal Industries, Ltd. Two-phase stainless steel
EP0757112A4 (en) * 1994-04-05 1997-06-18 Sumitomo Metal Ind Two-phase stainless steel
EP0683241A3 (en) * 1994-05-21 1996-05-08 Park Yong S Duplex stainless steel with high corrosion resistance.
EP0692547B1 (en) * 1994-07-11 2001-10-04 Metso Powdermet Oy Roll manufacture
US8710405B2 (en) * 2005-04-15 2014-04-29 Nippon Steel & Sumikin Stainless Steel Corporation Austenitic stainless steel welding wire and welding structure
CN103966522A (en) * 2013-01-25 2014-08-06 精工电子有限公司 Two-phase Stainless Steel, Method Of Manufacturing The Same, And Diaphragm, Pressure Sensor, And Diaphragm Valve Using Two-phase Stainless Steel
JP2019505677A (en) * 2015-12-23 2019-02-28 グッドウィン ピーエルシーＧｏｏｄｗｉｎ Ｐｌｃ Steel, welding consumables, cast or forged or stretched products, welding methods, welded products, and heat treatment methods
WO2020158111A1 (en) * 2019-01-30 2020-08-06 Ｊｆｅスチール株式会社 Duplex stainless steel, seamless steel pipe, and production method for duplex stainless steel
JP6747628B1 (en) * 2019-01-30 2020-08-26 Ｊｆｅスチール株式会社 Duplex stainless steel, seamless steel pipe, and method for producing duplex stainless steel
CN111197144A (en) * 2020-02-21 2020-05-26 青岛三庆金属有限公司 High-temperature-resistant stainless steel composition for food heating container

Also Published As

Publication number Publication date
DE69222027D1 (en) 1997-10-09
ITRM920309A1 (en) 1993-10-24
ATE157710T1 (en) 1997-09-15
IT1257695B (en) 1996-02-01
ITRM920309A0 (en) 1992-04-24
EP0566814B1 (en) 1997-09-03

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