US3807991A - Ferritic stainless steel alloy - Google Patents

Ferritic stainless steel alloy Download PDF

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Publication number
US3807991A
US3807991A US00193698A US19369871A US3807991A US 3807991 A US3807991 A US 3807991A US 00193698 A US00193698 A US 00193698A US 19369871 A US19369871 A US 19369871A US 3807991 A US3807991 A US 3807991A
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United States
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percent
stainless steel
ferritic stainless
chromium
nitrogen
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Expired - Lifetime
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US00193698A
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English (en)
Inventor
E Gregory
F Kies
I Franson
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Airco Inc
Allegheny Ludlum Corp
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Airco Inc
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Priority to BE790330D priority Critical patent/BE790330A/xx
Application filed by Airco Inc filed Critical Airco Inc
Priority to US00193698A priority patent/US3807991A/en
Priority to CA152,429A priority patent/CA977588A/en
Priority to IT30269/72A priority patent/IT968754B/it
Priority to NL7214029.A priority patent/NL163269C/xx
Priority to GB4781472A priority patent/GB1381173A/en
Priority to CS727055A priority patent/CS202531B2/cs
Priority to ZA727488A priority patent/ZA727488B/xx
Priority to AU48071/72A priority patent/AU472652B2/en
Priority to SE7213767A priority patent/SE383168B/xx
Priority to JP10759072A priority patent/JPS5536703B2/ja
Priority to AT916072A priority patent/AT333326B/de
Priority to FR7238281A priority patent/FR2159039A5/fr
Priority to CH1573272A priority patent/CH551491A/fr
Priority to DE2253148A priority patent/DE2253148C3/de
Application granted granted Critical
Publication of US3807991A publication Critical patent/US3807991A/en
Assigned to ALLEGHENY LUDLUM CORPORATION, 1000 SIX PPG PLACE, PITTSBURGH, PA 15222-5479 A CORP. OF PA reassignment ALLEGHENY LUDLUM CORPORATION, 1000 SIX PPG PLACE, PITTSBURGH, PA 15222-5479 A CORP. OF PA ASSIGNMENT OF ASSIGNORS INTEREST. Assignors: BOC GROUP, INC., THE
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    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/005—Manufacture of stainless steel
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
    • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
    • C21C5/52—Manufacture of steel in electric furnaces
    • C21C5/5264—Manufacture of alloyed steels including ferro-alloys
    • 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
    • C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00—Technologies related to metal processing
    • Y02P10/20—Recycling

Definitions

  • ABSTRACT A high purity, low interstitial ferritic stainless steel which in the as-welded condition exhibits a combination of improved resistance to intergranular corrosion, good resistance to general corrosion and improved impact resistance.
  • the steel broadly contains by weight from about 20.0 percent to about 35.0 percent chromium, from about 0.75 percent to about 1.20 percent molybdenum, from about 0.10 percent to about 0.30 percent silicon, up to about 0.020 percent phosphorous, up to about 0.020 percent sulfur, up to about 0.0030 percent carbon, from about 0.0050 percent to about 0.0125 percent nitrogen and columbium from about 13 to about 29 times the nitrogen content.
  • Stainless steel alloys are generally grouped into three broad classes; martensitic, ferritic and austenitic. These classes are established on the basis of the predominating alloy crystal structure at room temperature. The ultimate crystal structure depends upon the alloying elements utilized and their respective proportions. Two of the more important factors which often govern the selection of'a stainless steel alloy for a particular application are the desired physical properties and cost. Design engineers strive for optimum physical properties at the lowest cost. Quite naturally the most suitable stainless steel is very often also the most expensive.
  • austenitic stainless steels are more expensive than ferritic stainless steels because of the presence of nickel in amounts generally ranging from 6 to 22 percent.
  • ferritic stainless steels due to one very significant limitation of ferritic stainless steels, the more expensive austenitic stainless steels are generally selected.
  • ferritic stainless steel The utility of ferritic stainless steel is usually severely limited because as the chromium concentration is increased toughness at room temperature sharply decreases. Austenitic stainless steel is not so affected. Therefore, although a ferritic stainless steel containing more than percent chromium may exhibit corrosion resistance comparable to a more expensive nickel bearing austenitic stainless steel, the latter steel would generally be selected because it is ductile at room temperature whereas the ferritic steel is brittle.
  • a further limitation on the utility of ferritic stainless steel is the susceptibility of this steel toward intergranular corrosion.
  • intergranular corrosion can be minimized by reducing the carbon and/or nitrogen content of the alloy or by stabilizing the composition by employing stabilizers such as titanium or columbium, or by selective heat treatments.
  • Sensitization to corrosion involves the intergranular precipitation of chromium carbides, nitrides or carbo-nitrides when the alloy is exposed to elevated temperatures and thereafter slowly cooled. The principal effect is the depletion of chromium in areas adjacent to the grain boundaries. This depletion creates a reduced corrosion resistance in these chromium depleted areas resulting in nonuniform corrosion resistance.
  • austenitic stainless steels Although austenitic stainless steels have superior toughness at low temperatures they also have definite deficiencies, including susceptibility to stress corrosion cracking and sensitization. Furthermore, austenitic steels work harden more rapidly than do ferritic stainless steels. To produce austenitic stainless sheet or strip intermediate heat treatments are required during reduction to restore ductility in order to achieve desired thickness. Generally speaking, austenitic stainless steels work harden more rapidly than ferritic stainless steels thereby necessitating intermediate annealing.
  • An object of this invention is the provision of a ferritic stainless steel alloy that combines toughness, improved resistance to intergranular corrosion and good resistance to general corrosion.
  • Another object of this invention is the provision of a low cost ferritic stainless steel alloy that exhibits good wide range corrosion resistance and freedom from corrosion sensitization as well as good impact resistance at room temperature.
  • Still a further object of this invention is to provide a ferritic stainless steel alloy that is characterized by improved impact resistance, and resistance to intergranular corrosion after heating to an elevated temperature followed by air (slow) cooling.
  • a further object of this invention is to provide a high chromium nickel free stainless steel that is applicable for weldments fabricated from plate, sheet, strip, pipe or rod and wire products without subsequent heat treatments.
  • a further object of this invention is to provide a ferritic stainless steel with high purity and a low level of interstitials manufactured from low cost charge materials and scrap.
  • a further object of this invention is to provide a method for making a ferritic stainless steel having resistance to intergranular corrosion together with toughness.
  • a ferritic stainless steel with high purity and a low level of interstitials that may be made by any suitable high purity steel making process.
  • One such process comprises vacuum melting and refining a charge of low cost raw materials and thereafter further refining it by exposing the melt to hard vacuum and high power level electron beams.
  • the content of this alloy in weight percent can range from about 20.0 percent to about 35.0 percent and preferably from 25.0 percent to 27.5 percent chromium, from about 0.75 percent to 1.20 percent molybdenum, up to about 0.020 percent phosphorous, up to about 0.020 percent sulfur, and from about 0.10 percent to about 0.30 percent silicon.
  • the impact strength is enhanced by limiting the carbon content to not more than about 0.0030 percent (30 parts per million) and the nitrogen content to not more than about 0.0125 percent (125 parts per million). These extremely low levels of carbon and nitrogen can be achieved by vacuum refining. Electron beam refining methods have been found especially useful in the production of alloys of such purity.
  • Essential in the novel alloy is a small but critical columbium content. The columbium content of this alloy ranges from about 13 to about 29 times the nitrogen content.
  • FIG. 1 is a graph showing the relationship between the columbium to nitrogen ratio and the ductile-tobrittle transition temperature (DBTT) after air cooling one-half inch plate from 1,800 F.
  • DBTT ductile-tobrittle transition temperature
  • FIG. 2 is a schematic showing of a steel making process and apparatus suitable for the production of the novel alloy.
  • Chromium 20.0 to 35.0 (Broad) Chromium 25.0 to 27.5 (Preferred) Molybdenum 0.75 to 1.20
  • This invention relates to ferritic stainless steels having chromium in the broad range of 20.0 to 35.0 percent and more particularly within the narrow range of 25.0 to 27.5 percent. Within these chromium ranges iron-chromium alloys exhibit a particular high degree of corrosion resistance in highly corrosive media. However, ferritic alloys with chromium contents within these ranges also tend to be brittle, even at temperatures much above room temperature. As previously stated an object of this invention is to provide a ferritic stainless alloy in the 20 to 35 percent chromium range that retains all of the benefits of this amount of chromium while overcoming the problems associated therewith, particularly the problem of embrittlement.
  • maintaining the molybdenum content in the range of 0.75 to 1.20 percent improves the corrosion resistance of the alloy in reducing environments. Furthermore, additions of molybdenum within this range enhance the alloys resistance to pitting corrosion. If the steel of this invention has a molybdenum content less than 0.75 percent, corrosion resistance is impaired. Too much molybdenum can be detrimental in that it increases cost and in large amounts can adversely affect the toughness of the alloy. We prefer, in the alloys claimed in this application, to keep molybdenum below about 1.20 percent.
  • the silicon content should be kept within the range of about 0.10 to 0.30 percent. Silicon, in amounts greater than approximately 0.10 percent, performs the dual function of accelerating oxygen removal during refining and improving the alloys high temperature oxidation resistance. Silicon in excess of 0.30 percent is not desirable because of solid solution hardening.
  • the carbon content should be not more than about 30 ppm. This low content is readily achieved by electron beam refining the melt in vacuo. Reducing the carbon content to this level improves toughness by lowering the ductile-to-brittle transition temperature (DB'I'I), the transition temperature being defined as that temperature at which the amount of energy that can be absorbed on impact without causing fracture very rapidly decreases. Below this temperature the capacity to absorb energy is very low and the behavior of the alloy is said to be brittle. Above the transition temperature the capacity to absorb energy is relatively high and the material is said to be tough. Further, a carbon content below 30 ppm improves the alloys resistance to intergranular corrosion by reducing the amount of carbon available to form chromium carbides. By preventing the formation of chromium carbides the alloy matrix will not be depleted in chromium if subjected to prolonged heating, and its resistance to intergranular corrosion is retained.
  • DB'I'I ductile-to-brittle transition temperature
  • the nitrogen content should be not greater than about ppm. Reducing nitrogen'to this level improves toughness as evidenced by the reduced DBT'T. Likewise, low levels of nitrogen reduce the alloy's susceptibility to intergranular corrosion. Higher levels of nitrogen can cause chromium to be depleted from the alloy matrix and precipitate at the grain boundries as a chromium nitride in much the same manner as chromium carbides. Reducing the nitrogen content of the alloy minimizes the precipitation of objectionable chromium nitrides. Most important however is the discovery that within the range of 50 ppm to 125 ppm the detrimental effects of nitrogen are neutralized by the small critical addition of columbium contemplated by this invention.
  • the amount of columbium utilized in this alloy is critical.
  • the amount of columbium utilized must be correlated with the nitrogen content of the alloy in a carefully defined critical ratio. Since it is virtually impossible (or at least impractical) to remove all the nitrogen from the alloy, the objects of the invention can be achieved only if residual nitrogen is tied up in such a manner that it cannot impair toughness or resistance to intergranular corrosion.
  • the transition temperature is reduced significantly by the addition of columbium in an amount related to the nitrogen content of the alloy. Reduction to about room temperature or below may be achieved when the Cb:N ratio is maintained within the range of about 13 to about 29. in the absence of columbium, even small amounts of nitrogen, e.g., 60 ppm, cause embrittlement.
  • the foregoing small columbium addition makes the air cooled DBTT insensitive to nitrogen variations between about 50 and about 125 ppm. When nitrogen content is less than about 50 ppm the alloy is ductile at room temperature without further modification. 0.05
  • the phosphorous content is preferablykept as low as possible and certainly below 0.020 percent because phosphorous in the alloy acts to elevate the DBTl.
  • the sulfur content of the steel should be kept to a low level. in any event, the sulfur content should not exceed about 0.020 percent. Large amounts of sulfur tend to form deliterious nonmetallic inclusions.
  • nickel, copper and cobalt contents of the steel should likewise be kept low.
  • nickel typically is present in amounts up to 0.10 percent, copper in amounts up to 0.015 percent and cobalt in amounts up to 0.04 percent.
  • the combined amount of these elements should not exceed about 0.25 percent because above that level the alloys resistance to stress corrosion cracking is adversely affected.
  • composition containing the maximum amounts of each of these several elements may not reliably achieve a DBTT of room temperature or less after air cooling from 1,800 F, but such a composi-' tion will exhibit significant improvement in this property over a similar material lacking the critical columbium addition.
  • the heats in Group I with a B or C prefix are commerically produced mill production heats. These heats were processed in a manner as hereinafter more fully described.
  • the remaining heats in Groups I, 11 and 111 with a MH prefix are laboratory heats remelted from mill heat 2B0005. These heats represent 40 pound melts having closely controlled columbium and nitrogen contents and were produced in a laboratory vacuum induction furnace.
  • the resulting ingots were conditioned by grinding and were subsequently hammer forged into one-half inch by 4 inches cross-section plate after soaking at 2,100 F for 2 hours.
  • compositions of the steels in this group are generally within the novel range of this invention except for the constituent columbium.
  • the columbium contents of the steels in this group are outside the critical ratio of l3 to 29 times the nitrogen content.
  • GROUP III The compositions of the steels in this group are all within the novel range of this invention and contain the correct critical amounts of columbium.
  • GROUP IV The composition of this heat contains a chromium content on the high side of the broad range. The columbium content exceeds the critical amount required for effective reduction of the DBTT. This'experimental heat was prepared from electrolytic chromium, vac uum remelted and high purity iron, vacuum refined.
  • Evaluating the physical properties of an alloy in order to predict performance can be accomplished by various recognized and accepted test procedures.
  • the individual test employed should approximate the ultimate alloy application. For example, static testing, such as tensile testing, wherein a load is applied slowly, is employed when ductility and a reproducible measure of strength is desired. Dynamic testing, such as impact testing wherein loading is applied suddenly such as by a blow from a hammer or pendulum, is employed where a measure of toughness is desired. Another form of testing is service testing wherein a specific property such as corrosion resistance can be evaluated.
  • Another technique used to predict service performance is to measure an alloys toughness;
  • a widely accepted test used for measuring toughness is the Charpy V-Notch Impact Test. In this test a specimen containing a carefully machined notch is employed. The specimen, supported at both ends as a beam, is broken by a single blow ofa swinging pendulum. The amount of energy absorbed in deforming and breaking the specimen determines the impact value. Specific details of this test are described in ASTM specification E 23-66, Part 31, l97l.
  • Typical mechanical properties for an alloy of the present invention are as follows:
  • a slab approximately 6 to 12 inches thick, approximately 38 inches wide and of a length sufficient to produce the finished plate length is utilized.
  • the slab is heated in a slab reheating furnace -to approximately 2,150 E and rolled in a series of passes on a plate-rolling mill toa final thickness of 3/16 inch to 3 inches.
  • the plate is transferred to a cooling bed or heat treated and cooled to an ambient temperature.
  • the finished plate should then be suited for processing into a desired product, such as heat-exchanger tubes, pipes, and vessels for corrosive media.
  • the alloy of this invention can be rolled into a plate of desired thickness in a manner as hereinbefore described, heat treated and 9 then fabricated (including welding) into a fihished product without final heat treatments.
  • sions that formed during solidification are elongated 'into'stringers. These stringer inclusions are orientated ers because they lie parallel to the direction of impact and thereby tend to reduce the specimens ability to withstand sudden loading.
  • the steel of this invention is inherently clean and free from non-metallic inclusions. Therefore, transverse specimens are free from this internal weakness. This results in essentially similar impact properties in both longitudinal and transverse directions. Uniform impact properties in both directions is also a desirable fabricating characteristic.
  • the alloys of Group II and Group III eithibit greater resistance to intergranular corrosion than the alloys of Group I. This is attributed to the columbium .addition inthe Groups II and III alloys. As previously noted, interstitial levels measured in parts-per-million can still impair intergranular corrosion resistance.
  • the small addition of columbium acts to tie up any nitrogen or carbon dissolved in the matrix thereby preventing the precipitation of chromium carbides or nitrides at the grain boundries upon cooling. Preventing precipitation of these carbides or nitrides at the grain boundries insures a uniform distribution of chromium throughout the matrix, thereby eliminating the possibility of intergranular corrosion.
  • the steel of this invention may be refined commercially in an electron-beam-heated cold-hearth fum'ace such as the furnace schematically illustrated in FIG. 2.
  • the main refining chamber (A) houses the coreless induction-melting furnace (B).
  • a bulk charger and isolation valve (C) are mounted on the furnace lid for charging the melt stock, including some alloy additives, without exposing the furnace to ambient atmosphere.
  • An isolation valve (D) separates the main refining chamber from the holding furnace and secondary refining chamber (F) and final refining chamber (G).
  • Molten metal in the main induction furnace is teemed by means of a retractable, refractorylined launder (E), through valve D to the induction-heated holding furnace (H).
  • the holding furnace provides the surge capacity needed for the continuous feeding of molten metal to theelectron-beam-heated hearth and continuous casting stations.
  • the hearth (I) is, in fact, a series of hearths arranged in cascade-fashion to prevent back-mixing.
  • the final hearth transfers the metal to a water-cooled copper tundish (J), which conducts it-to a casting mold (K).
  • the required columbium addition is preferably made after the refining has progressed to the point at which the final nitrogen level can be predicted.
  • a critical amount of columbium is added so as to provide a Cb:N ratio of 13 to 29 in the final composition.
  • Columbium may be added in the form of ferro-columbium. Columbium in this form has a lower melting point that pure columbium and, therefore, dissolves into the melt more rapidly. It is preferred in the above described process, to add the columbium prior to the passage of the alloy down the electron beam refining hearths. This produces-a more homogeneous product.
  • a ferritic stainless steel product having the composition defined in claim 1 and having a DBTT below room temperature after air cooling from l,800 F.
  • a hot rolled ferritic stainless steel product characterized by its combined toughness and corrosion resistance and characterized further by exhibiting impact strength in the transverse direction substantially equal to the impact strength in the longitudinal direction, said product consisting by weight percent essentially of:
  • chromium from about 20.0 percent to about 35.0
  • molybdenum from about 0.75 percent to about 1.20 percent, silicon from about 0.10 percent to about 0.30 percent, phosphorous up to about 0.020 percent, sulfur up to about 0.020 percent, carbon up to about 0.0030 percent, nitrogen from about 0.0050 percent to about 0.0125 percent, columbium from aboutl3 to about 29 times the nitrogen content, and the remainder substantially all iron.
  • a single phase ferritic alloy free of nickel and characterized by high resistance to corrosion, good weldability, and toughness said alloy consisting essentially of Fecontaining by weight 25 to 27.5 percent chromium, 0.75 to 1.20 percent molybdenum, 0.10 to 0.30 percent silicon, and containing as impurities not more than 30 ppm carbon, from about 50 ppm to about ppm nitrogen, not more than 200 ppm sulfur, and not more than 200 ppm phosphorous, and further containing, as an essential element, columbium in an amount of at least 0.05 percent by weight and not more than about 29 times the nitrogen content of the alloy.
  • a ferritic stainless steel consisting, by weight percent, essentially of carbon up to about 0.0030 percent, phosphorous up to about 0.020 percent, sulfur up to about 0.020 percent, silcon from about 0.10 percent to about 0.30 percent, chromium from about 20.0 percent to about 35.0 percent, molybdenum from about 0.75 percent to about 1.2 percent, nitrogen from about 0.0050 percent to about.0.0l25 percent, columbium from about 13 to about 29 times the nitrogen content, and the remainder substantially all iron, said steel being ductile in the water quenched condition to less than 0 F and having substantially equivalent transverse and longitudinal impact strength levels, and having an intergranular corrosion rate of less than 400 microns per year.

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US00193698A 1971-10-29 1971-10-29 Ferritic stainless steel alloy Expired - Lifetime US3807991A (en)

Priority Applications (15)

Application Number Priority Date Filing Date Title
BE790330D BE790330A (fr) 1971-10-29 Alliage d'acier inoxydable ferritique
US00193698A US3807991A (en) 1971-10-29 1971-10-29 Ferritic stainless steel alloy
CA152,429A CA977588A (en) 1971-10-29 1972-09-25 Ferritic stainless steel alloy
IT30269/72A IT968754B (it) 1971-10-29 1972-10-09 Lega di acciaio inossidabile ferritico
NL7214029.A NL163269C (nl) 1971-10-29 1972-10-17 Werkwijze voor het bereiden van ferritische staal- legeringen, alsmede hieruit geheel of grotendeels vervaardigde, gevormde voortbrengselen.
GB4781472A GB1381173A (en) 1971-10-29 1972-10-17 Ferritic stainless steel alloy
CS727055A CS202531B2 (en) 1971-10-29 1972-10-19 Ferritic rustless steel and method of making the same
ZA727488A ZA727488B (en) 1971-10-29 1972-10-20 Ferritic stainless steel alloy
AU48071/72A AU472652B2 (en) 1971-10-29 1972-10-23 Ferritic stainless steel alloy
SE7213767A SE383168B (sv) 1971-10-29 1972-10-25 Ferritiskt, rostfritt stal och sett att framstella detta
JP10759072A JPS5536703B2 (enrdf_load_stackoverflow) 1971-10-29 1972-10-26
AT916072A AT333326B (de) 1971-10-29 1972-10-27 Ferritischer korrosionsbestandiger stahl und verfahren zu seiner herstellung
FR7238281A FR2159039A5 (enrdf_load_stackoverflow) 1971-10-29 1972-10-27
CH1573272A CH551491A (fr) 1971-10-29 1972-10-27 Alliage d'acier inoxydable ferritique.
DE2253148A DE2253148C3 (de) 1971-10-29 1972-10-30 Verfahren zur Herstellung eines ferritischen, korrosionsbeständigen Stahls und dessen Verwendung

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US00193698A US3807991A (en) 1971-10-29 1971-10-29 Ferritic stainless steel alloy

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US (1) US3807991A (enrdf_load_stackoverflow)
JP (1) JPS5536703B2 (enrdf_load_stackoverflow)
AT (1) AT333326B (enrdf_load_stackoverflow)
AU (1) AU472652B2 (enrdf_load_stackoverflow)
BE (1) BE790330A (enrdf_load_stackoverflow)
CA (1) CA977588A (enrdf_load_stackoverflow)
CH (1) CH551491A (enrdf_load_stackoverflow)
CS (1) CS202531B2 (enrdf_load_stackoverflow)
DE (1) DE2253148C3 (enrdf_load_stackoverflow)
FR (1) FR2159039A5 (enrdf_load_stackoverflow)
GB (1) GB1381173A (enrdf_load_stackoverflow)
IT (1) IT968754B (enrdf_load_stackoverflow)
NL (1) NL163269C (enrdf_load_stackoverflow)
SE (1) SE383168B (enrdf_load_stackoverflow)
ZA (1) ZA727488B (enrdf_load_stackoverflow)

Cited By (12)

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US3953201A (en) * 1974-03-07 1976-04-27 Allegheny Ludlum Industries, Inc. Ferritic stainless steel
US3957544A (en) * 1972-03-10 1976-05-18 Crucible Inc. Ferritic stainless steels
US3963532A (en) * 1974-05-30 1976-06-15 E. I. Du Pont De Nemours And Company Fe, Cr ferritic alloys containing Al and Nb
US4059440A (en) * 1975-02-01 1977-11-22 Nippon Steel Corporation Highly corrosion resistant ferritic stainless steel
US4119765A (en) * 1976-04-27 1978-10-10 Crucible Inc. Welded ferritic stainless steel articles
WO2003048402A1 (en) * 2001-11-30 2003-06-12 Ati Properties, Inc. Ferritic stainless steel having high temperature creep resistance
US20060286433A1 (en) * 2005-06-15 2006-12-21 Rakowski James M Interconnects for solid oxide fuel cells and ferritic stainless steels adapted for use with solid oxide fuel cells
US20060285993A1 (en) * 2005-06-15 2006-12-21 Rakowski James M Interconnects for solid oxide fuel cells and ferritic stainless steels adapted for use with solid oxide fuel cells
US7981561B2 (en) 2005-06-15 2011-07-19 Ati Properties, Inc. Interconnects for solid oxide fuel cells and ferritic stainless steels adapted for use with solid oxide fuel cells
US8888838B2 (en) 2009-12-31 2014-11-18 W. L. Gore & Associates, Inc. Endoprosthesis containing multi-phase ferrous steel
US10639719B2 (en) 2016-09-28 2020-05-05 General Electric Company Grain boundary engineering for additive manufacturing
WO2021006729A1 (en) 2019-07-05 2021-01-14 Stamicarbon B.V. Ferritic steel parts in urea plants

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS511312A (ja) * 1974-06-22 1976-01-08 Nippon Steel Corp Kotaishokuseifueraitosutenresuko
JPS5333917A (en) * 1976-09-10 1978-03-30 Nisshin Steel Co Ltd High chrome ferritic stainless steel
CA1184402A (en) * 1980-04-11 1985-03-26 Sumitomo Metal Industries, Ltd. Ferritic stainless steel having good corrosion resistance

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US2183715A (en) * 1938-05-21 1939-12-19 Electro Metallurg Co Corrosion resistant steel alloy
US2624671A (en) * 1951-01-19 1953-01-06 Union Carbide & Carbon Corp Ferritic chromium steels
US2905577A (en) * 1956-01-05 1959-09-22 Birmingham Small Arms Co Ltd Creep resistant chromium steel

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US2183715A (en) * 1938-05-21 1939-12-19 Electro Metallurg Co Corrosion resistant steel alloy
US2624671A (en) * 1951-01-19 1953-01-06 Union Carbide & Carbon Corp Ferritic chromium steels
US2905577A (en) * 1956-01-05 1959-09-22 Birmingham Small Arms Co Ltd Creep resistant chromium steel

Cited By (26)

* Cited by examiner, † Cited by third party
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US3957544A (en) * 1972-03-10 1976-05-18 Crucible Inc. Ferritic stainless steels
US3953201A (en) * 1974-03-07 1976-04-27 Allegheny Ludlum Industries, Inc. Ferritic stainless steel
US3963532A (en) * 1974-05-30 1976-06-15 E. I. Du Pont De Nemours And Company Fe, Cr ferritic alloys containing Al and Nb
US4059440A (en) * 1975-02-01 1977-11-22 Nippon Steel Corporation Highly corrosion resistant ferritic stainless steel
US4119765A (en) * 1976-04-27 1978-10-10 Crucible Inc. Welded ferritic stainless steel articles
EP2767607A1 (en) 2001-11-30 2014-08-20 ATI Properties, Inc. Ferritic stainless steel having high temperature creep resistance
EP2278036A1 (en) 2001-11-30 2011-01-26 ATI Properties, Inc. Ferritic stainless steel having high temperature creep restistance
US20040050462A1 (en) * 2001-11-30 2004-03-18 Grubb John F. Ferritic stainless steel having high temperature creep resistance
EP1448803A4 (en) * 2001-11-30 2006-08-16 Ati Properties Inc FERRITIC STAINLESS STEEL WITH HIGH-TEMPERATURE CRYSTAL STRENGTH
WO2003048402A1 (en) * 2001-11-30 2003-06-12 Ati Properties, Inc. Ferritic stainless steel having high temperature creep resistance
US6641780B2 (en) 2001-11-30 2003-11-04 Ati Properties Inc. Ferritic stainless steel having high temperature creep resistance
CN100370049C (zh) * 2001-11-30 2008-02-20 Ati资产公司 具有抗高温蠕变性的铁素体不锈钢
US8158057B2 (en) 2005-06-15 2012-04-17 Ati Properties, Inc. Interconnects for solid oxide fuel cells and ferritic stainless steels adapted for use with solid oxide fuel cells
US7842434B2 (en) 2005-06-15 2010-11-30 Ati Properties, Inc. Interconnects for solid oxide fuel cells and ferritic stainless steels adapted for use with solid oxide fuel cells
US7981561B2 (en) 2005-06-15 2011-07-19 Ati Properties, Inc. Interconnects for solid oxide fuel cells and ferritic stainless steels adapted for use with solid oxide fuel cells
US20110229803A1 (en) * 2005-06-15 2011-09-22 Ati Properties, Inc. Interconnects for solid oxide fuel cells and ferritic stainless steels adapted for use with solid oxide fuel cells
US20060285993A1 (en) * 2005-06-15 2006-12-21 Rakowski James M Interconnects for solid oxide fuel cells and ferritic stainless steels adapted for use with solid oxide fuel cells
US8173328B2 (en) 2005-06-15 2012-05-08 Ati Properties, Inc. Interconnects for solid oxide fuel cells and ferritic stainless steels adapted for use with solid oxide fuel cells
US20060286433A1 (en) * 2005-06-15 2006-12-21 Rakowski James M Interconnects for solid oxide fuel cells and ferritic stainless steels adapted for use with solid oxide fuel cells
US8888838B2 (en) 2009-12-31 2014-11-18 W. L. Gore & Associates, Inc. Endoprosthesis containing multi-phase ferrous steel
US9987121B2 (en) 2009-12-31 2018-06-05 W. L. Gore & Associates, Inc. Method of making an endoprosthesis containing multi-phase stainless steel
US10639719B2 (en) 2016-09-28 2020-05-05 General Electric Company Grain boundary engineering for additive manufacturing
WO2021006729A1 (en) 2019-07-05 2021-01-14 Stamicarbon B.V. Ferritic steel parts in urea plants
US11746084B2 (en) 2019-07-05 2023-09-05 Stamicarbon B.V. Ferritic steel parts in urea plants
US12084406B2 (en) 2019-07-05 2024-09-10 Stamicarbon B.V. Ferritic steel parts in urea plants
US12325679B2 (en) 2019-07-05 2025-06-10 Stamicarbon B.V. Ferritic steel parts in urea plants

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Publication number Publication date
ATA916072A (de) 1976-03-15
AT333326B (de) 1976-11-10
DE2253148B2 (de) 1979-08-30
NL163269C (nl) 1980-08-15
DE2253148C3 (de) 1984-07-05
GB1381173A (en) 1975-01-22
JPS4851815A (enrdf_load_stackoverflow) 1973-07-20
BE790330A (fr) 1973-04-19
NL7214029A (enrdf_load_stackoverflow) 1973-05-02
AU472652B2 (en) 1976-06-03
JPS5536703B2 (enrdf_load_stackoverflow) 1980-09-22
CS202531B2 (en) 1981-01-30
CH551491A (fr) 1974-07-15
SE383168B (sv) 1976-03-01
DE2253148A1 (de) 1973-05-03
IT968754B (it) 1974-03-20
AU4807172A (en) 1974-04-26
FR2159039A5 (enrdf_load_stackoverflow) 1973-06-15
CA977588A (en) 1975-11-11
ZA727488B (en) 1974-05-29

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