US3873306A - Ferritic alloy with high temperature strength containing dispersed intermetallic TiSi - Google Patents

Ferritic alloy with high temperature strength containing dispersed intermetallic TiSi Download PDF

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Publication number
US3873306A
US3873306A US381288A US38128873A US3873306A US 3873306 A US3873306 A US 3873306A US 381288 A US381288 A US 381288A US 38128873 A US38128873 A US 38128873A US 3873306 A US3873306 A US 3873306A
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United States
Prior art keywords
alloy
titanium
silicon
ferritic alloy
aluminum
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Expired - Lifetime
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US381288A
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English (en)
Inventor
Philip M Giles
Halle Abrams
Arnold R Marder
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Bethlehem Steel Corp
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Bethlehem Steel Corp
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Publication date
Application filed by Bethlehem Steel Corp filed Critical Bethlehem Steel Corp
Priority to US381288A priority Critical patent/US3873306A/en
Priority to CA204,838A priority patent/CA1030786A/fr
Priority to GB3165174A priority patent/GB1446682A/en
Priority to FR7425112A priority patent/FR2237973B1/fr
Priority to DE2434956A priority patent/DE2434956A1/de
Priority to BE146777A priority patent/BE817896A/fr
Priority to JP49083722A priority patent/JPS5071510A/ja
Application granted granted Critical
Publication of US3873306A publication Critical patent/US3873306A/en
Anticipated expiration legal-status Critical
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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
    • C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of silicon

Definitions

  • said alloy consists essentially of, by weight, up to about 0.1% carbon, from about 4.0 to about 8.2% aluminum, about 0.2 to 4.0% silicon, about 0.05 to 2.0% titanium, with a preferred silicon/titanium ratio between about 1.0 to 4.0, and the balance iron, incidental impurities and additions which do not materially affect the attainment of the desired properties.
  • This invention relates to a high-strength, low-cost iron-aluminum ferritic alloy, characterized by a microstructure containing a fine TiSi intermetallic type precipitate dispersed uniformly throughout the matrix of the grains thereof.
  • the alloy also possesses hightemperature oxidation-resistance, a characteristic ideally suited for application where thermal shock, such as cyclic heating and cooling, are experienced. While not intending to unduly limit this invention, applications which can take advantage of the properties hereof are high temperature exhaust systems in automobiles, jet engines, and in the petrochemical industry.
  • high-temperature oxidation-resistant materials were selected from high cost nickel and cobalt superalloys, austenitic stainless steels, or ceramic materials.
  • the prior art moved to lower or less rich alloys.
  • U.S. Pat. No. 1,641,752 teaches a ferrous alloy resistant to oxidation at high temperatures, by including therein a high percentage of aluminum. Specifically, said alloy contains from 12 to 20% aluminum, and about 1 to 5% ofa grain refining material, among which are included titanium and chromium.
  • the high-temperature oxidationresistance is due at least in part to the formation of a protective coating of oxide of the aluminum on the exposed surfaces of the ferrous alloy.
  • such alloys are of limited suitability under cyclic heating and cooling conditions wherein thermal shock results in flaking and spalling of the oxide coating. Accordingly, one of the critical requirements ofa suitable alloy is its ability to resist such flaking and spalling.
  • the material of the latter patent is characterized by an aluminum gradient between the coating and core, and as a result would have different densities and coefficients of expansion. Thermal cracks could develop from said cyclic treatments, as well as an eventual deterioration thereof due to continued diffusion and depletion of the aluminum from the coating.
  • ironaluminum alloys have served as a base alloy for developing high-temperature oxidation-resistant alloys.
  • U.S. Pat. No. 3,698,964 represents a further effort in this direction.
  • the alloy of said patent is an iron base alloy containing chromium and aluminum and/or silicon. More specifically, the alloying additions thereto are on the order of from 1 to 5%.
  • the improved oxidation-resistance, or decrease in weight gain with temperature, is attributed to the formation of alumina, or a complex oxide of iron and aluminum. While such an alloy appears to exhibit superior oxidation-resistance when compared to a Type 301 austenitic stainless steel, no mention is made as to its high temperature strength.
  • the present invention teaches a ferritic alloy which is not only oxidation-resistant at elevated temperatures, but possesses high strength in conjunction therewith.
  • the present invention relates to a high-strength ironaluminum ferritic alloy which is not only resistant to oxidation at high temperatures, but is resistant to surface flaking and spalling when subjected to thermal shocking as a result of cyclic heating and cooling. More particularly, said invention covers an alloy consisting essentially of, by weight, up to about 0.1% carbon, about 4.0 to 8.2% aluminum, up to about 10.5% chromium, about 0.2 to 4.0% silicon, about 0.05 to 2.0% titanium, with a preferred silicon titanium ratio between about 1.0 to 4.0 and the balance iron, incidental impurities and additions which do not materially affect the attainment of the desired properties.
  • the unexpected high-temperature strength is derived from the precipitation at very high temperatures, ofa fine TiSi intermetallic type precipitate of high thermal stability, said precipitate being uniformly dispersed throughout the matrix of the grains thereof.
  • FIGURE is a graph showing the increase or change in strength, over a range of elevated temperatures, for two alloys of this invention (base alloys plus titanium and silicon according to the teachings herein) and base alloys plus no more than one of the elements from the group consisting of silicon, titanium, or an increase in the carbon content.
  • This invention is directed to the family of iron-aluminum alloys, more particularly to the wrought ferritic alloysthereof which may be employed in appli cations where the ability to withstand thermal shock is critical.
  • the alloys hereof are characterized by a combination of high-strength and oxidation-resistance under conditions of cyclic heating at temperatures up to about 1,800 F. Typical applications where the latter conditions prevail are high temperature exhaust systems, such as a thermal reactor in automobiles, jet engines, and in the petrochemical industry. While the mention of same is not intended as a limitation on this invention, it is believed that a brief discussion thereof will help in understanding the significance of this invention and the contributions offered thereby.
  • a thermal reactor is a container into which the hot exhaust gases flow from the automotive, jet or power producing engines, for further combustion. Air is also pumped into the reactor and admixed with said gases.
  • the reactor is generally of sufficient size (chamber volume) to give a long enough residence time of the believed that the prior art establishes the general performance of the iron-aluminum alloys to resist hightemperature oxidation, while said copending application establishes the specific capabilities of the alloys admixed gases to permit complete combustion of the 5 hereof to perform at temperatures up to about 2,500 residual hydrocarbons and carbon monoxide. Since the F. Accordingly, the data therefrom is incorporated by combustion reaction is so strongly exothermic, temperreference and will not be presented here.
  • the invention becomes the unexpected increase in strength severe conditions of high temperature, oxidizing enviof the alloys as a result of the precipitation ofa fine TiSi ronment, and intermittent operation (cyclic heating intermetallic type precipitate of high thermal stability. and cooling), call for a material capable of meeting The synergism resulting from the controlled addition of th se conditi ns,
  • the alloys of th present invention both titanium and silicon is believed clearly demonnot only fulfill these conditions, but accomplish it at a S ed from he FIGURE, and TABLE ll below. For low material cost.
  • a preferred commium num position is one containing at least about 8.0% chro- 7 mium, aluminum between about 6.0 to 7.0%, titanium '3 '8 ⁇ ? 3'8 2'; :8; between about 0.2 to 1.2%, silicon between about 0.6 c I012 79 I004 ,01 to 1.8%, and a titanium/carbon ratio of at least 4.0.
  • the ingots were slowly heated (at least 5 hours) in this regard, the production of wrought strip and to a soaking temperature between about 2,025 to sheet by conventional rolling practices requires that the 2,130 F.
  • the ingots were rematerial be sufficiently ductile for said rolling to be efduced at about /2 inches per pass to a plate thickness fected.
  • the finishing temperatures varied bealloys, the ductility thereof drops below a practical tween about 1,650 to 1,850 E, and from here the level when the aluminum begins to exceed about 8% by plates were slowly cooled to ambient temperatures by weight. Chromium, when added to an Al-Fe alloy, burying in sand.
  • the curve (0,; Up) represents the difference in strength observed at various temperatures, when the titanium containing Alloy E is contrasted to Alloy F, comparable in all regards except the titanium content.
  • curve (0,, 0 represents the difference in strength at the varying temperatures between Alloy D and Alloy C.
  • the alloys were comparable except for the 0.61% by weight silicon in the former.
  • a high temperature high strength ferritic alloy characterized by a microstructure containing a small, well dispersed, spherical TiSi type intermetallic precipitate and consisting essentially of, by weight, up to about 0.1% carbon, from about 4.0 to about 8.2% aluminum, up to about 10.5% chromium, from about 0.2 to about 4.0% silicon, from about 0.05 to about 2.0% titanium, where the silicon content is at least equal to the titanium content to insure the development of said precipitate, with the balance iron.
  • a ferritic alloy characterized by high temperature strength and consisting essentially of, by weight, up to about 0.1% carbon, from about 6.0 to about 7.0% aluminum, from about 8.0 to about 10.5% chromium, from about 0.6 to about 1.8% silicon, from about 0.2 to about 1.2% titanium, where the silicon content is at least equal to the titanium content, with the balance iron.
  • microstructure is characterized by a structure containing a small, well dispersed, spherical intermetallic precipitate.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Powder Metallurgy (AREA)
  • Manufacture Of Alloys Or Alloy Compounds (AREA)
  • Coating With Molten Metal (AREA)
US381288A 1973-07-20 1973-07-20 Ferritic alloy with high temperature strength containing dispersed intermetallic TiSi Expired - Lifetime US3873306A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US381288A US3873306A (en) 1973-07-20 1973-07-20 Ferritic alloy with high temperature strength containing dispersed intermetallic TiSi
CA204,838A CA1030786A (fr) 1973-07-20 1974-07-16 Alliage ferritique a forte resistance aux hautes temperatures
GB3165174A GB1446682A (en) 1973-07-20 1974-07-17 Ferritic alloy with high temperature strength
FR7425112A FR2237973B1 (fr) 1973-07-20 1974-07-18
DE2434956A DE2434956A1 (de) 1973-07-20 1974-07-19 Bei hohen temperaturen oxidationsbestaendige eisenhaltige legierung
BE146777A BE817896A (fr) 1973-07-20 1974-07-19 Alliages ferritiques resistants a haute temperature
JP49083722A JPS5071510A (fr) 1973-07-20 1974-07-20

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US381288A US3873306A (en) 1973-07-20 1973-07-20 Ferritic alloy with high temperature strength containing dispersed intermetallic TiSi

Publications (1)

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US3873306A true US3873306A (en) 1975-03-25

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US381288A Expired - Lifetime US3873306A (en) 1973-07-20 1973-07-20 Ferritic alloy with high temperature strength containing dispersed intermetallic TiSi

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US (1) US3873306A (fr)
JP (1) JPS5071510A (fr)
BE (1) BE817896A (fr)
CA (1) CA1030786A (fr)
DE (1) DE2434956A1 (fr)
FR (1) FR2237973B1 (fr)
GB (1) GB1446682A (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4929289A (en) * 1988-04-05 1990-05-29 Nkk Corporation Iron-based shape-memory alloy excellent in shape-memory property and corrosion resistance
US4933027A (en) * 1988-04-05 1990-06-12 Nkk Corporation Iron-based shape-memory alloy excellent in shape-memory property, corrosion resistance and high-temperature oxidation resistance
US5578265A (en) * 1992-09-08 1996-11-26 Sandvik Ab Ferritic stainless steel alloy for use as catalytic converter material
US6923923B2 (en) 2001-12-29 2005-08-02 Samsung Electronics Co., Ltd. Metallic nanoparticle cluster ink and method for forming metal pattern using the same
DE102007056144A1 (de) * 2007-11-16 2009-05-20 Volkswagen Ag Abgaskrümmer oder Turboladergehäuse aus einer FeAl-Stahllegierung
WO2013178629A1 (fr) * 2012-05-29 2013-12-05 Thyssenkrupp Steel Europe Ag Acier fe-al-cr résistant au fluage à chaud

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS63128151A (ja) * 1986-11-18 1988-05-31 Toyo Seiko Kk 耐火物補強用金属製品
DE19634524A1 (de) * 1996-08-27 1998-04-09 Krupp Ag Hoesch Krupp Leichtbaustahl und seine Verwendung für Fahrzeugteile und Fassadenverkleidungen
DE19820806B4 (de) * 1998-05-09 2004-03-04 Max-Planck-Institut Für Eisenforschung GmbH Verwendungen eines Leichtbaustahls

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3660173A (en) * 1969-06-25 1972-05-02 Toyo Kogyo Co Method of preparing corrosion resistant metallic articles
US3676109A (en) * 1970-04-02 1972-07-11 Cooper Metallurg Corp Rust and heat resisting ferrous base alloys containing chromium and aluminum

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3660173A (en) * 1969-06-25 1972-05-02 Toyo Kogyo Co Method of preparing corrosion resistant metallic articles
US3676109A (en) * 1970-04-02 1972-07-11 Cooper Metallurg Corp Rust and heat resisting ferrous base alloys containing chromium and aluminum

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4929289A (en) * 1988-04-05 1990-05-29 Nkk Corporation Iron-based shape-memory alloy excellent in shape-memory property and corrosion resistance
US4933027A (en) * 1988-04-05 1990-06-12 Nkk Corporation Iron-based shape-memory alloy excellent in shape-memory property, corrosion resistance and high-temperature oxidation resistance
US5578265A (en) * 1992-09-08 1996-11-26 Sandvik Ab Ferritic stainless steel alloy for use as catalytic converter material
US6923923B2 (en) 2001-12-29 2005-08-02 Samsung Electronics Co., Ltd. Metallic nanoparticle cluster ink and method for forming metal pattern using the same
DE102007056144A1 (de) * 2007-11-16 2009-05-20 Volkswagen Ag Abgaskrümmer oder Turboladergehäuse aus einer FeAl-Stahllegierung
WO2013178629A1 (fr) * 2012-05-29 2013-12-05 Thyssenkrupp Steel Europe Ag Acier fe-al-cr résistant au fluage à chaud

Also Published As

Publication number Publication date
FR2237973B1 (fr) 1978-07-13
DE2434956A1 (de) 1975-02-13
GB1446682A (en) 1976-08-18
FR2237973A1 (fr) 1975-02-14
JPS5071510A (fr) 1975-06-13
CA1030786A (fr) 1978-05-09
BE817896A (fr) 1975-01-20

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