US3856515A - Ferritic stainless steel - Google Patents

Ferritic stainless steel Download PDF

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Publication number
US3856515A
US3856515A US00301067A US30106772A US3856515A US 3856515 A US3856515 A US 3856515A US 00301067 A US00301067 A US 00301067A US 30106772 A US30106772 A US 30106772A US 3856515 A US3856515 A US 3856515A
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United States
Prior art keywords
chromium
steel
steels
corrosion
molybdenum
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Expired - Lifetime
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US00301067A
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English (en)
Inventor
H Brandis
R Oppenheim
G Lennartz
H Kiesheyer
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Deutsche Edelstahlwerke GmbH
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Deutsche Edelstahlwerke GmbH
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Priority claimed from DE2153186A external-priority patent/DE2153186A1/de
Priority claimed from DE2153766A external-priority patent/DE2153766C3/de
Application filed by Deutsche Edelstahlwerke GmbH filed Critical Deutsche Edelstahlwerke GmbH
Application granted granted Critical
Publication of US3856515A publication Critical patent/US3856515A/en
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    • 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

Definitions

  • this new steel gives substantially greater resistance to corrosion by fluids containing chlorides, higher notched bar impact and tensile test values, has in general substantially improved cold formability, and has other advantageous properties which may be increased by the addition'of alloying elements.
  • the ferritic stainless steels are fundamentally resistant to stress-corrosion cracking as can be shown by testing them in boiling 42% magnesium-chloride solutions, or in a calcium-chloride solution having a mercury-chloride addition.
  • Such steels contain adequate chromium to develop passivity as required to make them qualify as stainless steels.
  • they contain up to from to chromium, an example being Type No. 446 of the American Iron and Steel Institute Standard Type Numbers, this steel containing from 23 to 27% chromium.
  • prior art ferritic stainless steels become brittle when cold-worked; they give low notched bar impact and tensile test values. This brittleness is exhibited not only at subnormal temperatures but also at temperatures up to 100C. and even somewhat higher. Also, when heated, as during welding, and quickly cooled, they may be brittle.
  • ferritic stainless steels Another disadvantage suffered by ferritic stainless steels has been that their general resistance to corrosion when subjected to fluids containing chlorides has been insufficient to permit their use when such conditions are encountered. This lack of resistance to such corrosion has prevented the use of ferritic stainless steels in many applications, the austenitic stainless steels being used instead.
  • the object of the present invention is to provide a ferritic highchromium stainless steel which is free from the disadvantages of prior art ferritic high-chromium stainless steels, to a degree permitting it to compete more successfully with the austenitic stainless steels in all fields.
  • this object is attained by a steel containing from 18 to chromium and having very low carbon and nitrogen contents, the total of the two preferably being not greater than 0.01%, and having a molybdenum content of from at least 0.5% and up to 6.0%, the balance being iron, the
  • new steel optionally including certain additional alloying elements.
  • the carbon and nitrogen content in conjunction withthe high chromium content is insufficient to result in the formation of chromium carbides or nitrides at the grain boundaries of the steel, this resulting in the steel having adequately high notched bar impact and tensile test values even if the steel is rendered course grained by being heated.
  • the molybdenum provides for adequate corrosion resistance when the steel is subjected to corrosive fluids containing chlorides.
  • FIG. I graphically shows notched impact strengths at differing temperatures
  • FIG. 2 graphically shows tensile stength characteristics
  • FIG. 3 illustrates a bent specimen of a sheet of steel
  • FIG. 4 graphically shows the pitting tendency offour steels.
  • ferritic high-chromium stainless steels of this invention have compositions within the following ranges:
  • compositional percentages are by weight.
  • Chromium contents below 18% do not provide sufficient passivity to be considered acceptable when meeting severe corrosion conditions; more than 35% of chromium does not appear to provide further improvement in passivity.
  • the low carbon and nitrogen contents prevent the formation of excessive compounds at the grain boundaries with the attendant trouble this might cause.
  • the maximum content of carbon and nitrogen are specified at 0.015%, each it is preferable that their total should not exceed 0.01%.
  • novel molybdenum content specified for use in these new ferritic stainless steels provides a very substantial and decisive improvement in their resistance to corrosive pitting and passivity. It is surprisingly effective in rendering the new steels generally resistant to corrosion when subject to the attack of fluids containing chlorides, this contrasting with the lack of resistance to such attacks by prior art ferritic highchromium stainless steels. At the same time their fundamental resistance to stress-corrosion cracking is not deleteriously affected.
  • the new steels essentially consist of the chromium contents. the maintenance of carbon and nitrogen at the low levels specified, and the molyb denum contents specified.
  • the balance is, of course, mainly iron, the reference to impurities being with the understanding that such impurities. must be kept below values that would produce a harmful effect on the properties of the steel.
  • the optional use of the other alloying elements is explained as follows:
  • the copper specified its use of up to 2%, preferably from 0.05 to 1.5%, and of silicon up to 3%, preferably from 0.5 to 2%, has the advantage of further improving the resistance to corrosion.
  • the same advantages are obtained by the optional addition of up to 0.5%, preferably 0.001 to 0.01 of boron. These additions also improve the weldability and the resistance of the steel to intergranular corrosion in the transition zones of welds.
  • ferritic stainless steels made in accordance with this invention have great resistance to corrosion under oxidizing conditions as might be expected.
  • these steels, even under reducing conditions have excellent resistance to corrosion, far superior to those of known austenitic chromium-nickel steels which also contain molybdenum.
  • ferritic steels of a composition within the ranges specified herein would remain more passive at substantially lower potentials than do the corresponding chromium-nickel and chromium-nickel-molybdenum steels having almost the same chromium content.
  • Reduction mediums. which because of their great negative redox potential lead to activation and thus to dissolving of the high-chromium austenitic steel X5 CrNiMo 25 25, are not capable of activating the new ferritic chromium-steel having about the same chromium content; these mediums are even capable of stabilizing the passive state.
  • FIG. 2 shows the strength characteristics of two production melts of the steel 28/2 CrMo containing 0.002%C and also 0.0025% N, after a heat-treatment for 30 minutes at 875% C, followed by quenching in
  • FIG. 3 shows the example of a 4 mm thick metal chromium-steels made in accordance with this invensheet of the 28/2 CrMo steel containing C N equal tion have excellent mechanical characteristics, and in to or less than 0.01%. which was welded to other simi particular good notch impact strength and notch tensile lar material by the electric plasma-arc welding process. strength, as is shown by the following Table 4, and and then bent at a sharp 180 angle lengthwise of and FIGS.
  • Table 5 are given the compositions of four differ- Table 5 Steel C Si Mn Cr Mo S P N C+N 7, a 72 72 a 71 /l A 0.003 0.01 0.01 19.9 4.85 0.008 0.005 0.001 0.004 B 0.001 0.01 0.01 23.8 3.43 0.008 0.005 0.001 0.002 c 0.002 0.01 0.01 28.1 2.11 0.008 0.005 0.001 0.003 o 0.004 0.01 0.01 l9.6 2.00 0.006 0.005 0.001 0.005
  • molybdenum is with respect to resistance to Temp. 1 Steel Type CrMo W 20/5 CrMo corros on pitting about three times as efficacious as 0.002% c, 0.001% c. 0.003% c, chromium; that 1s each 1% of molybdenum has in this 0002? N 002% N 090W? N respect the same effect as 3% of chromium.
  • FIG. 4 where there are plotted for the In this Table 4, which for each temperature for the four 3 A, B, C and D, their liability to pitting in 3% measurement of each type of steel givesthree mea- Nacl m a temperathrefangle f 10000 sured values of notch impact strengths, it is seen that 40 Cause of the almost slmllar P potenllalst steels At all specimens at room temperature are sure to have and should Show eqhahy h f P notch impact strengths of better than 30 mkp/cm?
  • ferritic stainless steels of the range of composition to be used in accordance with this invention form a secure basis for allowing the use of these steels for the building of pressure-tanks under specified obligations or warranties, and for making possible their use in a wide field of application in the chemical industry, and also in a general way in processes under reducing conditions, and in particular in the field of producing and processing organic chemical substances.
  • the ferritic stainless steel of this invention is moreover suitable for ship building, for building appratus and equipment, such as heat exchangers, e.g., handling sea water, for pumps, piping, and the like.

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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)
  • Treatment Of Steel In Its Molten State (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
US00301067A 1971-10-26 1972-10-26 Ferritic stainless steel Expired - Lifetime US3856515A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE2153186A DE2153186A1 (de) 1971-10-26 1971-10-26 Verwendung ferritischer chromstaehle als korrosionsbestaendiger werkstoff fuer den chemischen apparatebau
DE2153766A DE2153766C3 (de) 1971-10-28 1971-10-28 Verwendung ferritischer Chrom-Molybdän-Stähle für Apparatebauteile

Publications (1)

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US3856515A true US3856515A (en) 1974-12-24

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US00301067A Expired - Lifetime US3856515A (en) 1971-10-26 1972-10-26 Ferritic stainless steel

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US (1) US3856515A (enrdf_load_stackoverflow)
JP (1) JPS4850917A (enrdf_load_stackoverflow)
ES (1) ES407973A1 (enrdf_load_stackoverflow)
FR (1) FR2158943A5 (enrdf_load_stackoverflow)
GB (1) GB1359629A (enrdf_load_stackoverflow)
IT (1) IT969494B (enrdf_load_stackoverflow)
NL (1) NL7214519A (enrdf_load_stackoverflow)
SE (1) SE382646B (enrdf_load_stackoverflow)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3953201A (en) * 1974-03-07 1976-04-27 Allegheny Ludlum Industries, Inc. Ferritic stainless steel
US3993445A (en) * 1974-11-27 1976-11-23 Allegheny Ludlum Industries, Inc. Sintered ferritic stainless steel
US4055448A (en) * 1973-04-10 1977-10-25 Daido Seiko Kabushiki Kaisha Ferrite-austenite stainless steel
US4139377A (en) * 1976-01-13 1979-02-13 Granges Nyby Ab Ferritic chrome steels of high notched bar impact strength and method of making same
US4155752A (en) * 1977-01-14 1979-05-22 Thyssen Edelstahlwerke Ag Corrosion-resistant ferritic chrome-molybdenum-nickel steel
US4216013A (en) * 1976-05-28 1980-08-05 Christer Aslund Ductile ferritic steels and their use for metallic articles, especially welded constructions
US4284439A (en) * 1977-08-17 1981-08-18 Granges Myby Ab Process for the production of sheet and strip from ferritic, stabilized, stainless chromium-molybdenum-nickel steels
US4331474A (en) * 1980-09-24 1982-05-25 Armco Inc. Ferritic stainless steel having toughness and weldability
US4340424A (en) * 1974-04-23 1982-07-20 Daido Tokushuko Kabushiki Kaisha Ferritic stainless steel having excellent machinability and local corrosion resistance
US4374683A (en) * 1980-02-29 1983-02-22 Sumitomo Metal Industries, Ltd. Process for manufacturing ferritic stainless steel sheet having good formability, surface appearance and corrosion resistance
US4465525A (en) * 1980-03-01 1984-08-14 Nippon Steel Corporation Ferritic stainless steel having excellent formability
US5489345A (en) * 1991-12-19 1996-02-06 Sumitomo Metal Industries, Ltd. Steel for use in exhaust manifolds of automobiles
US20050129563A1 (en) * 2003-12-11 2005-06-16 Borgwarner Inc. Stainless steel powder for high temperature applications
US20060130938A1 (en) * 2002-10-04 2006-06-22 Firth Ag Ferritic steel alloy
US10883160B2 (en) 2018-02-23 2021-01-05 Ut-Battelle, Llc Corrosion and creep resistant high Cr FeCrAl alloys

Families Citing this family (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT338854B (de) * 1972-09-04 1977-09-26 Ver Edelstahlwerke Ag Ferritische bzw. ferritisch-austenitische stahllegierungen fur gegenstande, die gegen saure- und wassergemische bis 70grad c korrosionsbestandig sind
JPS5418215B2 (enrdf_load_stackoverflow) * 1974-01-29 1979-07-05
JPS5421809B2 (enrdf_load_stackoverflow) * 1974-05-01 1979-08-02
JPS5853062B2 (ja) * 1974-04-28 1983-11-26 ダイドウセイコウ カブシキガイシヤ 遠心分離機の回転体等に適したフエライト−オ−ステナイト系ステンレス鋼
JPS51117916A (en) * 1975-04-10 1976-10-16 Daido Steel Co Ltd Ferrite-austenite type two phase stainless steel
JPS5333917A (en) * 1976-09-10 1978-03-30 Nisshin Steel Co Ltd High chrome ferritic stainless steel
SE436577B (sv) * 1980-01-03 1985-01-07 Allegheny Ludlum Steel Ferritiskt rostfritt stal och anvendning av dylikt
SE436576C (sv) * 1980-01-03 1987-03-16 Allegheny Ludlum Steel Ferritiskt rostfritt stal och anvendning av dylikt
ATE12527T1 (de) * 1981-01-16 1985-04-15 Allegheny Ludlum Steel Ferritischer, rostfreier, korrosionsbestaendiger, schweissbarer stahl mit geringem gehalt an zwischengittersubstanzen und verfahren zu seiner herstellung.
JPS58199848A (ja) * 1982-05-15 1983-11-21 Showa Denko Kk フエライト系ステンレス鋼
DE3221087A1 (de) * 1982-06-04 1983-12-08 Thyssen Edelstahlwerke AG, 4000 Düsseldorf Verfahren zur erzeugung und verarbeitung hochlegierter nichtrostender ferritischer chrom-molybdaen-nickel-staehle
JPH0772326B2 (ja) * 1986-04-23 1995-08-02 日本鋼管株式会社 粗製リン酸中で優れた耐食性を有するフエライト系ステンレス鋼
US4942922A (en) * 1988-10-18 1990-07-24 Crucible Materials Corporation Welded corrosion-resistant ferritic stainless steel tubing having high resistance to hydrogen embrittlement and a cathodically protected heat exchanger containing the same
JP4267367B2 (ja) 2002-06-19 2009-05-27 新日本製鐵株式会社 原油油槽用鋼およびその製造方法、原油油槽およびその防食方法

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2121590A (en) * 1936-04-09 1938-06-21 Siemens Ag Vacuum-and gas-tight vessel for electric apparatus
US2141016A (en) * 1936-11-19 1938-12-20 Payson Peter Alloy steel
US2200545A (en) * 1934-01-04 1940-05-14 Rustless Iron & Steel Corp Rustless iron manufacture
US2624669A (en) * 1951-01-19 1953-01-06 Union Carbide & Carbon Corp Ferritic chromium steels
US2624671A (en) * 1951-01-19 1953-01-06 Union Carbide & Carbon Corp Ferritic chromium steels
US3562781A (en) * 1964-11-17 1971-02-09 Armco Steel Corp Titanium-bearing chromium-nickel-copper stainless steel
US3713812A (en) * 1970-08-03 1973-01-30 Steel Corp Ferritic stainless steels with improved drawability and resistance to ridging
US3726668A (en) * 1969-11-29 1973-04-10 Boehler & Co Ag Geb Welding filling material

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2200545A (en) * 1934-01-04 1940-05-14 Rustless Iron & Steel Corp Rustless iron manufacture
US2121590A (en) * 1936-04-09 1938-06-21 Siemens Ag Vacuum-and gas-tight vessel for electric apparatus
US2141016A (en) * 1936-11-19 1938-12-20 Payson Peter Alloy steel
US2624669A (en) * 1951-01-19 1953-01-06 Union Carbide & Carbon Corp Ferritic chromium steels
US2624671A (en) * 1951-01-19 1953-01-06 Union Carbide & Carbon Corp Ferritic chromium steels
US3562781A (en) * 1964-11-17 1971-02-09 Armco Steel Corp Titanium-bearing chromium-nickel-copper stainless steel
US3726668A (en) * 1969-11-29 1973-04-10 Boehler & Co Ag Geb Welding filling material
US3713812A (en) * 1970-08-03 1973-01-30 Steel Corp Ferritic stainless steels with improved drawability and resistance to ridging

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4055448A (en) * 1973-04-10 1977-10-25 Daido Seiko Kabushiki Kaisha Ferrite-austenite stainless steel
US3953201A (en) * 1974-03-07 1976-04-27 Allegheny Ludlum Industries, Inc. Ferritic stainless steel
US4340424A (en) * 1974-04-23 1982-07-20 Daido Tokushuko Kabushiki Kaisha Ferritic stainless steel having excellent machinability and local corrosion resistance
US3993445A (en) * 1974-11-27 1976-11-23 Allegheny Ludlum Industries, Inc. Sintered ferritic stainless steel
US4139377A (en) * 1976-01-13 1979-02-13 Granges Nyby Ab Ferritic chrome steels of high notched bar impact strength and method of making same
US4216013A (en) * 1976-05-28 1980-08-05 Christer Aslund Ductile ferritic steels and their use for metallic articles, especially welded constructions
US4155752A (en) * 1977-01-14 1979-05-22 Thyssen Edelstahlwerke Ag Corrosion-resistant ferritic chrome-molybdenum-nickel steel
US4284439A (en) * 1977-08-17 1981-08-18 Granges Myby Ab Process for the production of sheet and strip from ferritic, stabilized, stainless chromium-molybdenum-nickel steels
US4374683A (en) * 1980-02-29 1983-02-22 Sumitomo Metal Industries, Ltd. Process for manufacturing ferritic stainless steel sheet having good formability, surface appearance and corrosion resistance
US4465525A (en) * 1980-03-01 1984-08-14 Nippon Steel Corporation Ferritic stainless steel having excellent formability
US4331474A (en) * 1980-09-24 1982-05-25 Armco Inc. Ferritic stainless steel having toughness and weldability
US5489345A (en) * 1991-12-19 1996-02-06 Sumitomo Metal Industries, Ltd. Steel for use in exhaust manifolds of automobiles
US20060130938A1 (en) * 2002-10-04 2006-06-22 Firth Ag Ferritic steel alloy
US20050129563A1 (en) * 2003-12-11 2005-06-16 Borgwarner Inc. Stainless steel powder for high temperature applications
US10883160B2 (en) 2018-02-23 2021-01-05 Ut-Battelle, Llc Corrosion and creep resistant high Cr FeCrAl alloys

Also Published As

Publication number Publication date
ES407973A1 (es) 1975-10-01
JPS4850917A (enrdf_load_stackoverflow) 1973-07-18
NL7214519A (enrdf_load_stackoverflow) 1973-05-01
IT969494B (it) 1974-03-30
SE382646B (sv) 1976-02-09
GB1359629A (en) 1974-07-10
FR2158943A5 (enrdf_load_stackoverflow) 1973-06-15

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