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
  • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
• • 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
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12736—Al-base component
  • Y10T428/1275—Next to Group VIII or IB metal-base component
  • Y10T428/12757—Fe
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/12—All metal or with adjacent metals
  • Y10T428/12493—Composite; i.e., plural, adjacent, spatially distinct metal components [e.g., layers, joint, etc.]
  • Y10T428/12771—Transition metal-base component
  • Y10T428/12861—Group VIII or IB metal-base component
  • Y10T428/12951—Fe-base component
  • Y10T428/12972—Containing 0.01-1.7% carbon [i.e., steel]

Definitions

• ABSTRACT A low alloy steel for use as a substrate for aluminum or aluminum alloy coatings, the steel containing from 0.01 percent to 0.13 percent carbon, from 0.5 percent to 3 percent chromium, from 0.8 percent to 3 percent aluminum, from 0.4 percent to 1.5 percent silicon, from 0.1 percent to 0.6 percent manganese, from 0.1 percent to 1 percent titanium and remainder substantially iron.
• the steel has good oxidation resistance at elevated temperature, good weldability and formability, thereby'enhancing its utility for fabrication into a variety of wrought coated products.
• This invention relates to a chromiumaluminum silicon-titanium steel of low alloy content for use as-fia substrate fo r aluminum or aluminum alloy coatings,
• Aluminum coated carbon steel has proved to be not completely satisfactoryfor some high temperature applications.
• the automotive industry has substituted stainless steels such as Armco 409(containing 0.05 percent carbon, l l percent chromium, traces of aluminum. residual nickel, 0.5 percent titanium and remainder iron) and other stainless steels containing 1 l percent or more chromium.
• the cost of such steel is high, thus making it undesirable for proposed use in automotive exhaust systems, such as catalytic converters, and
• J. Caule et al discloses an iron base alloy with good ox idation resistance at temperatures of, about 700 110 800? C (about l,300 to l,475 F).
• the alloy of this patent contains up to 2 percent. carbon. l percent to 5. percent chromium, 1 percent to 4 percent aluminum, and/or l percent to 4 percent silicon. up to 1.5 percent manganese, up to 2 percent copper, up to 0.20'percent total of nickel, molybdenum, vanadium and other alloying elements.
• .U.S. Pat. No: 2,835,669 issued Mar. 4,.1958, toE. Herzog,. discloses a steel, andga heat treatment therefonwhereina microstructure, is produced having resistance to stress-corrosion cracking in wet hydrogen sulfideatmospheres.
• the steel of thispatent contains from 0.08 percent to 0.20 percent ,carbon, from 0.60 percent to 5.0 percent chromium, from 0.15 percentto 1.20 percent aluminum, from 0.30 percent to I20 percent manganese, from 0.
• the present invention provides a low alloy steel containing chromium, aluminum, silicon and titanium (preferably with a total alloy content of less than about 5 percent) which provides in sheet form a substrate for aluminum or aluminum alloy coatings, coated sheet being readily formable into w rt iugh t articles having good oxidation resistance at elevated temperature, 7
• steel of the invention consists essentially of fromabbtitttdl percent to about 0. l 3 percent carbonl from about'05percent to about L 3 percent chromium;'fronfabout- 0.8 percent to about 3 percent aluminum, from about 0.4 percent to about 1 .5pereent silicon; from about 0. l 'p'ercent to about 0.6 percent manganesejfrom about 0.1 percent to about I percent titanium. and remainderiron except for incidental impurities.,Molybde'numand vanadium are restricted to a maximum of about 0.05 percent each, and copper, nickel and other austenite stabilizers to less than about'0LZ percent each. l
• the carbon, chromium, aluminum; silicon and titanium percentage pranges are critical and departure therefrom results in loss of one or more of the above properties. Control of the critically low molybdenum,
• Carbon is essential in an amount of at least about 0.0l percent in order to provide the necessary strength in the steel. More than about 0.13 percent carbon cannot be tolerated because of its adverse effect upon the weldability, formability and and general mechanical properties of the steel. and because it is a strong austenite former.
• At least 0.5 percent chromium in combination with at least about 0.8 percent aluminum and about 0.4 percent silicon is necessary in order to provide good oxidation resistance. A maximum of 3 percent chromium should be observed in order to minimize cost and avoid processing difficulties.
• At least about 0.8 percent aluminum is necessary not onlyfor oxidation resistance at elevated temperature but also to provide adequate tensile strength. More than 3 percent aluminum results in a loss of formability and workability.
• At least about 0.4 percent silicon is essential since it co-operates with the chromium and aluminum to impart oxidation resistance. However. a maximum of about l.5 percent silicon should be observed since amounts in excess thereof also result in loss of formability and workability.
• Titanium is essential in an amount of at least about 0.1 percent in order to impart good weldability to the steel. Moreover. excess titanium over that needed to stabilize carbon has been found to improve the oxidation resistance at elevated temperature. This excess can be slight in view of the high cost of titanium and ofthe relatively low residual sulfur. nitrogen and oxygen contents of the steel of the invention. Preferably the titanium content is 8 times the carbon content. and a maximum of about 1 percent titanium should thus be observed at the carbon levels contemplated herein. Since it is known that eolumbium and/or zirconium generally function in an equivalent manner in stainless steels. it is considered within the scope of the invention to substitute eolumbium and/or zirconium in whole or in part for titanium.
• Such substitution would be on a stoiehio metric basis. with a minimum weight ratio of columbium or zirconium to carbon of 8: l. preferably at least about 10:]. Columbium and/or zirconium would thus range from about 0. 10 percent to about 1.5 percent if substituted for titanium.
• the above materials were hot rolled from 2,100" F (l.l4'-) C) from 1 inch by 3 inch ingots to 0.1 inch thickness. Samples were annealed at l,700 F (927 C) for 10 minutes, descaled and cold rolled to 0.05 inch thickness. It should be recognized that annealing the hot rolled material is optional. Tensile strengths were determined on the cold rolled samples at this stage while the remainder of the cold rolled strip was annealed at l.600 F (87l C) for 6 minutes and pickled. This material was tested for the remaining mechanical properties reported below in Table I].
• the yield strength of the 1 percent chromium alloy was about 12 ksi lower and the tensile strength about 8 ksi lower than the steels of the invention containing from about 1.7 percent to about 2 percent aluminum with chromium ranging from 0.5 percent to 2 percent.
• the elongation values of these steels of the invention were about equivalent to that of Sample Code l5.
• the carbon content should not exceed about 0.06 percent, that aluminum should range from about 1.7 to about 2 percent in combination with at least about 1.7 percent chromium and at least about 0.6 percent silicon.
• TA V ature. good formability, and high strength said article consisting of an outer layer applied by hot dip coating Oxidation Tests chosen from the class consisting of aluminum, and alu- (yl'llc /5 minum alloys. and a ferritic substrate consisting essensumplc Weighl mum.
• said article consisting of an outer ciiet (I M mined '35 titles 150m]; 143 layer applied by hot dip coating chosen from the class (2 Al CUZIlCLl I35 C ⁇ L'lt, 1500F 1&2 consisting of aluminum, and aluminum alloys, and a I v i v v v o '7 territic substrate consisting essentially of, by weight percent, from about 0.04 percent to about 0.06 percent Th d d th t n th t f h carbon, from about 1.7 percent to about 2.1 percent l that "l 5 e6 e chromium, from about 1.7 percent to about 2.0 percent Present cxhlbltcd gold Sculmg reslsmnce aluminum,from about 0.6 percent to about 0.9 percent both in still all and Cycllc tests Wlthout Coatmgs wlth silicon, from about 0.2 percent to about 0.4 percent aluminum coatings.
• the steels of the invention are supemanganese f uhuut 0 1 pfirccm to about rim to Arms yp 409 uncoilted Condltloll
• the titanium content is about 8 should further be noted that the still air tests on alumi times h carbon content, and remainder iron, except num and aluminum alloy coated plain carbon steel base f i id t l i iti metal or substrate showed this material to be com- 3.
• Articles for high temperature applications such as pletcly unacceptable for oxidation resistance at elespace heaters, automotive exhaust systems. and the vated temperatures of the order of 1,500 l,700 F, like.
• said articles comprising an outer hot dip coating because f blistering d warpugc chosen from the class consisting of aluminum, and alu- Optimum oxidation resistance is achieved in a steel mlnum y the Wclght of 51nd Colltmg bemg 31mm 1/2 of the invention containing about 2 percent chromium. luncc b i l foot of Sheet and a f l redued und about 2 percent aluminum. about percent Silicon and anncaled territic sheet metal base consisting essentially about 0.5 percent titanium (with titanium about 8 55 2 1 Wught P B 15 2 P 2 times the carbon content).
• Sample Code 86 is

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Laminated Bodies (AREA)
• Heat Treatment Of Steel (AREA)
• Coating With Molten Metal (AREA)
• Other Surface Treatments For Metallic Materials (AREA)

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Citations (7)

• 1973
  • 1973-06-25 US US373278A patent/US3905780A/en not_active Expired - Lifetime
• 1974
  • 1974-06-05 CA CA201,677A patent/CA1041323A/fr not_active Expired
  • 1974-06-07 GB GB2538374A patent/GB1471189A/en not_active Expired
  • 1974-06-07 IN IN1243/CAL/74A patent/IN142547B/en unknown
  • 1974-06-11 ZA ZA00743709A patent/ZA743709B/xx unknown
  • 1974-06-18 DE DE2429023A patent/DE2429023B2/de not_active Withdrawn
  • 1974-06-20 NL NL7408256A patent/NL7408256A/xx not_active Application Discontinuation
  • 1974-06-24 SE SE7408277A patent/SE401690B/xx unknown
  • 1974-06-24 BE BE145793A patent/BE816757A/fr not_active IP Right Cessation
  • 1974-06-24 JP JP7146574A patent/JPS558579B2/ja not_active Expired
  • 1974-06-24 BR BR5155/74A patent/BR7405155D0/pt unknown
  • 1974-06-24 AR AR254368A patent/AR202484A1/es active
  • 1974-06-24 ES ES427610A patent/ES427610A1/es not_active Expired
  • 1974-06-24 IT IT51701/74A patent/IT1016158B/it active
  • 1974-06-24 FR FR7421937A patent/FR2242480B1/fr not_active Expired

Patent Citations (7)

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