US3337331A - Corrosion resistant steel alloy - Google Patents

Corrosion resistant steel alloy Download PDF

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Publication number
US3337331A
US3337331A US428207A US42820765A US3337331A US 3337331 A US3337331 A US 3337331A US 428207 A US428207 A US 428207A US 42820765 A US42820765 A US 42820765A US 3337331 A US3337331 A US 3337331A
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Prior art keywords
corrosion
chromium
alloy
molybdenum
steel alloy
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US428207A
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Ljungberg Lars Gustaf Fredrik
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Santrade Ltd
Sandvik AB
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Sandvikens Jernverks AB
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Assigned to SANTRADE LTD. reassignment SANTRADE LTD. ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: SANDCO LIMITED
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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
    • C22C38/40—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

Definitions

  • ABSTRACT OF THE DISCLOSURE A steel alloy having a high resistance to corrosion, high strength and good workability and weldability consisting essentially of up to 0.15% carbon, l-22% chromium, 3-8% nickel, 1-2.8% silicon, 0-2.5% manganese, 2-4% molybdenum and altogether not more than 1.5% of carbide former selected from the group consisting of niobium, tantalum and titanium, the remainder being iron and the usual impurities, the alloy containing 40-95% by volume of ferrite and the remainder being austenite.
  • the present invention relates to a steel alloy with high resistance against corrosion, especially stress corrosion and pitting corrosion, and which at the same time has a high strength and good workability and weldability.
  • the steel alloy according to the invention can be used for manufacture of for instance welded or seamless tu-bes, strips, wires and other articles and products, which are especially suitable for use in chemical and similar industry, where corroding agents are used, and has in comparison with earlier known alloys a superior resistance against stress corrosion, for instance caused by halogen compounds, and also a substantially improved resistance against pitting corrosion.
  • the steel has also superior strength qualities and the objects made thereof are simple to manufacture by machining and welding.
  • Ferritic steels are resistant against stress corrosion and have a high strength but are less resistant against general corrosion and pitting corrosion. Austenitic steels are resistant against general corrosion and, alloyed with molybdenum, against pitting. They have a low strength and bad resistance against stress corrosion. Ferritic-austenitic steels are resistant against stress corrosion, have a good resistance against general corrosion and, when alloyed with molybdenum, against pitting corrosion. It is important that the relation ferrite-austenite in a ferriticaustenitic steel is balanced properly in order to obtain the desired properties. the workability of the steel, while too little austenite weakens the desired properties, i.e., the corrosion protection.
  • the steel alloy has a ferriticaustenitic structure and contains up to 0.15% carbon, l5-22% chromium, 3-8% nickel, 1-4% silicon, manganese, altogether up to 1.5% of one or more carbide formers as niobium (columbium), tantalum and titanium, and also 2-4% molybdenum, the contents of the alloy elements being mutually balanced in such a way that the steel contains 40-90% by volume of ferrite, the nest being austenite.
  • carbide formers as niobium (columbium), tantalum and titanium, and also 2-4% molybdenum
  • the steel according to the invention has a greater resistance against stress corrosion Too little ferrite gives diificulties with than austenitic steels.
  • the strength properties are superior to those of the austenitic steels, for instance of the type containing 18% chromium, 12% nickel and 2.5% molybdenum.
  • the corrosion properties is obtained a very substantial improvement of the corrosion properties especially with regard to pitting, but also against solutions of nonoxidizing character (for instance formic acid, oxalic acid and sulphuric acid).
  • the share of ferrite should be 40-95% by volume while the rest consists of austenite. Usually the share of ferrite should be more than 50% and often 55% by volume and should not exceed 90% by volume. A usually suitable value is about by volume.
  • the content of molybdenum should be 2-4%, and is in general chosen within the lower part of this range, the upper limit being 3.5% or often 3.2%.
  • the lower limit can in many cases be raised to 2.2%.
  • a convenient range for many purposes is 2.4-3%.
  • the nickel content range amount to 3-8% and the chromium content to 15-22%, preferably 16-21%.
  • the alloy can contain up to 0.15 carbon, but as a rule the carbon content should be substantially lower, for instance below 0.080% and preferably below 0.030%. As a suitable example can be mentioned carbon contents of 0:008-0.030%. If the carbon content lies within the upper part of said range it is suitable to add one or more carbide forming elements as niobium (columbium), tantalum and titanium at an amount up to 1.5%, usually up to 1.0%.
  • the alloy contains also from 1-2.8% silicon. It has been found that silicon efliciently contributes to the desired properties of the alloy, i.e., the resistance against stress corrosion. Silicon further eliminates the tendency of temper brittleness (brittleness at 475 C.) and the inven tion makes use of a quantity of silicon which is larger than usual in similar alloys.
  • the content of silicon can be defined by the following formula:
  • Silicon can to a certain extent substitute chromium as a passivating and thereby corrosion preventing element, and 1% silicon has in this respect been found equivalent to 2% chromium.
  • the content of chromium can, however, not be lowered too much as martensite is formed instead of austenite.
  • the substitution of chromium by silicon has Patented Aug. 22, 1967- the advantageous effect that the temper brittleness (brittleness at 475 C.) is suppressed.
  • the further advantage is also obtained that the substitution lessens the content of chromium, thereby lessening the tendency for formation of sigma-phase.
  • the silicon content should exceed 1.2% and often 1.4% and it should as a rule be at the most 2.8%.
  • the lower limit of the silicon content is 1.2-1.4% and the upper limit 1.9-2.1%.
  • the high content of silicon thus contributes to achieving a chromium content which is exceptionally low for a ferritic-austenitic steel, usually 16-20% chromium.
  • the defined ranges for the alloy elements are observed, especially for the molybdenum, the chromium and the nickel. This condition is, however, not sufficient but the quantities of the elements must further be balanced with relation to each other. If the content of chromium approaches the upper limit, the nickel content must also be raised and vice versa in order to obtain the desired phase relation. In case of a high content of molybdenum the content of nickel should be raised and/or the content of chromium be lowered.
  • the content of Ti, Nb (Cb) and/ or Ta should as above remarked not exceed 1.5%.
  • the content of nickel should be 3-8%, the quantity being balanced within this range in the way above defined. A too high content of nickel will cause a trend to form only austenite, and too little nickel will result in a trend to form ferrite or martensite instead of austenite.
  • the alloy can contain up to 2.5%, usually OJ-2%, for instance about 1.5 manganese. It can further contain up to 1% of additional elements which do not have an undesirable influence upon the properties. As an example of such elements can be mentioned vanadium and tungsten. For the rest the alloy contains iron with insignificant quantities of the impurities usually occuring in iron.
  • a suitable composition of the alloy for the objects according to the invention the following can be mentioned: 0.008-0.030% C, 16-21% Cr, 3-8% 4 Ni, 1.42.0 Si, 05-20% Mn, 2.0-3.2% Mo and a remainder consisting in the main of iron with usual impurities.
  • steel alloy having a high resistance against corrosion including stress corrosion and pitting corrosion, a high strength and good machining and welding properties, characterized in, that the alloy besides iron with usual impurities consists essentially of up to 0.15% carbon, 15-22% chromium, 3-8% nickel, 12.8% silicon, 0-2.5% manganese, altogether not more than 1.5% of a carbide former selected from the group consisting of niobium, tantalum and titanium and furthermore 2-4% molybdenum, the contents of the alloy elements being determined by the formula in which the chemical symbols stand for the quantities of the elements in percents and being so balanced in relation to each other that the steel contains 40-95% by volume of ferrite, the rest being austenite.
  • a carbide former selected from the group consisting of niobium, tantalum and titanium and furthermore 2-4% molybdenum
  • Steel alloy according to claim 1 characterized in, that it contains 0.008-0.030% carbon, 16-21% chromium, 3.46.8% nickel, 1.42.0% silicon, 0.5-2.0% manganese, 2.03.2% molybdenum and a remainder which in the main wholly consists of iron With usual impurities.
  • Steel alloy according to claim 1 characterized in, that it contains insignificant quantities, at the most up to 1%, of additional alloy elements selected from the group consisting of vanadium and tungsten, which have no negative influence upon the properties of the alloy.
  • ABSTRACT A steel alloy having a high resistance to corrosion, high strength and good workability and weldability consisting essentially of up to 0.15% carbon, 15-22% chromium, 3-8% nickel, 1-2.8% silicon, 02.5% manganese, 24% molybdenum and altogether not more than 1.5% of carbide former selected from the group consisting of niobium, tantalum and titanium, the remainder being iron and the usual impurities, the alloy containing 40-95% by volume of ferrite and the remainder being austenite.

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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)
US428207A 1964-01-29 1965-01-26 Corrosion resistant steel alloy Expired - Lifetime US3337331A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE1059/64A SE312240B (enrdf_load_stackoverflow) 1964-01-29 1964-01-29

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US3337331B1 US3337331B1 (enrdf_load_stackoverflow) 1967-08-22
US3337331A true US3337331A (en) 1967-08-22

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US (1) US3337331A (enrdf_load_stackoverflow)
JP (1) JPS4935486B1 (enrdf_load_stackoverflow)
DE (1) DE1303236B (enrdf_load_stackoverflow)
GB (1) GB1089824A (enrdf_load_stackoverflow)
SE (1) SE312240B (enrdf_load_stackoverflow)

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3620690A (en) * 1968-07-10 1971-11-16 Minnesota Mining & Mfg Sintered austenitic-ferritic chromium-nickel steel alloy
US3649252A (en) * 1967-08-16 1972-03-14 Henry William Kirkby Steels resistant to stress corrosion cracking
US3716353A (en) * 1970-03-10 1973-02-13 Nippon Kokan Kk Austenitic heat resisting steel
US3740213A (en) * 1968-05-16 1973-06-19 Bofors Ab Stainless ferrite-austenitic steel
JPS505972B1 (enrdf_load_stackoverflow) * 1970-05-11 1975-03-10
JPS508007B1 (enrdf_load_stackoverflow) * 1970-10-12 1975-04-01
US3910788A (en) * 1973-04-21 1975-10-07 Nisshin Steel Co Ltd Austenitic stainless steel
US3914506A (en) * 1972-07-10 1975-10-21 Mitsubishi Heavy Ind Ltd Welding material for austenitic stainless steels
US3925064A (en) * 1973-05-31 1975-12-09 Kobe Steel Ltd High corrosion fatigue strength stainless steel
JPS5361514A (en) * 1976-11-16 1978-06-02 Daido Steel Co Ltd Ferriteebased precipitation hardening type stainless steel
US4101347A (en) * 1977-05-06 1978-07-18 Daido Tokushuko Kabushiki Kaisha Ferrite-austenite stainless steel castings having an improved erosion-corrosion resistance
US4127428A (en) * 1975-08-02 1978-11-28 Japan Gasoline Co., Ltd. Stainless cast alloy steel for use at low temperatures
WO1979000100A1 (en) * 1977-08-17 1979-03-08 Graenges Nyby Ab A process for the production of sheet and strip from ferritic,stabilised,stainless chromium-molybdenum-nickel steels
US4264356A (en) * 1978-03-23 1981-04-28 Tohoku Special Steel Works Limited Ferritic precipitation-hardened soft magnetic stainless steel
US4612069A (en) * 1984-08-06 1986-09-16 Sandusky Foundry & Machine Company Pitting resistant duplex stainless steel alloy
US4640817A (en) * 1983-08-05 1987-02-03 Sumitomo Metal Industries, Ltd. Dual-phase stainless steel with improved resistance to corrosion by nitric acid
US5254184A (en) * 1992-06-05 1993-10-19 Carpenter Technology Corporation Corrosion resistant duplex stainless steel with improved galling resistance
US5474737A (en) * 1993-07-01 1995-12-12 The United States Of America As Represented By The Secretary Of Commerce Alloys for cryogenic service
US20080199349A1 (en) * 2005-05-10 2008-08-21 Chun Changmin High performance alloys with improved metal dusting corrosion resistance

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4391635A (en) * 1980-09-22 1983-07-05 Kubota, Ltd. High Cr low Ni two-phased cast stainless steel
SE453837B (sv) * 1986-09-12 1988-03-07 Avesta Ab Forfarande for utskiljningsherdning av ett ferrit-austenitiskt rostfritt stal
DE3901028A1 (de) * 1989-01-14 1990-07-19 Bayer Ag Nichtrostende knet- und gusswerkstoffe sowie schweisszusatzwerkstoffe fuer mit heisser, konzentrierter schwefelsaeure beaufschlagte bauteile

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2861883A (en) * 1956-02-09 1958-11-25 Cooper Alloy Corp Precipitation hardenable, corrosion resistant, chromium-nickel stainless steel alloy
US2920954A (en) * 1958-04-15 1960-01-12 Cooper Alloy Corp Stainless steel alloy of high hardness

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2861883A (en) * 1956-02-09 1958-11-25 Cooper Alloy Corp Precipitation hardenable, corrosion resistant, chromium-nickel stainless steel alloy
US2920954A (en) * 1958-04-15 1960-01-12 Cooper Alloy Corp Stainless steel alloy of high hardness

Cited By (20)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3649252A (en) * 1967-08-16 1972-03-14 Henry William Kirkby Steels resistant to stress corrosion cracking
US3740213A (en) * 1968-05-16 1973-06-19 Bofors Ab Stainless ferrite-austenitic steel
US3620690A (en) * 1968-07-10 1971-11-16 Minnesota Mining & Mfg Sintered austenitic-ferritic chromium-nickel steel alloy
US3716353A (en) * 1970-03-10 1973-02-13 Nippon Kokan Kk Austenitic heat resisting steel
JPS505972B1 (enrdf_load_stackoverflow) * 1970-05-11 1975-03-10
JPS508007B1 (enrdf_load_stackoverflow) * 1970-10-12 1975-04-01
US3914506A (en) * 1972-07-10 1975-10-21 Mitsubishi Heavy Ind Ltd Welding material for austenitic stainless steels
US3910788A (en) * 1973-04-21 1975-10-07 Nisshin Steel Co Ltd Austenitic stainless steel
US3925064A (en) * 1973-05-31 1975-12-09 Kobe Steel Ltd High corrosion fatigue strength stainless steel
US4127428A (en) * 1975-08-02 1978-11-28 Japan Gasoline Co., Ltd. Stainless cast alloy steel for use at low temperatures
JPS5361514A (en) * 1976-11-16 1978-06-02 Daido Steel Co Ltd Ferriteebased precipitation hardening type stainless steel
US4101347A (en) * 1977-05-06 1978-07-18 Daido Tokushuko Kabushiki Kaisha Ferrite-austenite stainless steel castings having an improved erosion-corrosion resistance
WO1979000100A1 (en) * 1977-08-17 1979-03-08 Graenges Nyby Ab A process for the production of sheet and strip from ferritic,stabilised,stainless chromium-molybdenum-nickel steels
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
US4264356A (en) * 1978-03-23 1981-04-28 Tohoku Special Steel Works Limited Ferritic precipitation-hardened soft magnetic stainless steel
US4640817A (en) * 1983-08-05 1987-02-03 Sumitomo Metal Industries, Ltd. Dual-phase stainless steel with improved resistance to corrosion by nitric acid
US4612069A (en) * 1984-08-06 1986-09-16 Sandusky Foundry & Machine Company Pitting resistant duplex stainless steel alloy
US5254184A (en) * 1992-06-05 1993-10-19 Carpenter Technology Corporation Corrosion resistant duplex stainless steel with improved galling resistance
US5474737A (en) * 1993-07-01 1995-12-12 The United States Of America As Represented By The Secretary Of Commerce Alloys for cryogenic service
US20080199349A1 (en) * 2005-05-10 2008-08-21 Chun Changmin High performance alloys with improved metal dusting corrosion resistance

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Publication number Publication date
SE312240B (enrdf_load_stackoverflow) 1969-07-07
DE1303236B (enrdf_load_stackoverflow) 1971-06-24
JPS4935486B1 (enrdf_load_stackoverflow) 1974-09-24
US3337331B1 (enrdf_load_stackoverflow) 1967-08-22
GB1089824A (en) 1967-11-08

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Owner name: SANTRADE LTD., LUCERNE, SWITZERLAND

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:SANDCO LIMITED;REEL/FRAME:003946/0360

Effective date: 19811231

B1 Reexamination certificate first reexamination