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US3144329A - Method for producing rolled steel products - Google Patents

Method for producing rolled steel products Download PDF

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Publication number
US3144329A
US3144329A US136082A US13608261A US3144329A US 3144329 A US3144329 A US 3144329A US 136082 A US136082 A US 136082A US 13608261 A US13608261 A US 13608261A US 3144329 A US3144329 A US 3144329A
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Prior art keywords
bars
iron
powder
rolling
content
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Expired - Lifetime
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US136082A
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Inventor
Frolich Ake Tjelvar
Smedstam John Arne
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Trafikaktiebolaget Grangesberg-Oxelosund
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Trafikaktiebolaget Grangesberg-Oxelosund
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C33/00Making ferrous alloys
    • C22C33/02Making ferrous alloys by powder metallurgy
    • C22C33/0235Starting from compounds, e.g. oxides
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21BMANUFACTURE OF IRON OR STEEL
    • C21B13/00Making spongy iron or liquid steel, by direct processes
    • C21B13/0086Conditioning, transformation of reduced iron ores
    • C21B13/0093Protecting against oxidation
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/10Reduction of greenhouse gas [GHG] emissions
    • Y02P10/134Reduction of greenhouse gas [GHG] emissions by avoiding CO2, e.g. using hydrogen

Definitions

  • This invention relates to a method for producing rolled steel products, preferably thin sheet, with low oxide content from oxidic iron powder, preferably sponge iron relatively rich in oxide, by imparting to the oxidic iron powder either during its manufacture or thereafter a content of carbon.
  • sponge iron show an excellent property of compressibility, rendering it possible to compress porous sponge iron in a rolling mill or press such, that a product of high density and strength is obtained. Even sponge iron in ground state can be compressed in the same manner. By sintering, after-pressing or rolling the compressed products, the strength can be increased still more. This method is applied in so-called powder-metallurgical manufacturing processes.
  • sponge iron nor sponge iron powder which are produced according to conventional reduction processes is adapted for use in the production of highgrade pressed or rolled products without having been subjected to a special after-treatment. This is partially due to the fact that sponge iron almost always includes considerable amounts of residue iron oxides which may sometimes even exceed It is easy to understand, that such impurity reduces the strength of compressed sponge iron products and, in general, deteriorates the quality of the material.
  • the object of the invention is substantially characterized in that the carbonaceous and oxidic iron powder is first pressed to sheet bars, that the sheet bars are sintered at 6001200 C., so that their carbon and oxide contents are substantially reduced, whereafter the bars by compression rolling are formed to billets which, finally, are subjected to cold rolling in conventional manner.
  • the production conditions of the iron powder are such, for example according to the H'tigan'as-method, that its carbon content can be adjusted, it is not necessary to admix further carbon to the iron powder.
  • the available iron-powder is produced according to a method, for example by reduction with hydrogen gas, which does not include the possibility of adjusting the carbon content, a certain amount of ashless carbonaceous material or pig iron powder, cementite or another metallic carbide should be admixed, so that the carbon content of the oxidic iron powder is adjusted to the oxide content of the latter.
  • the pressing of the powder to sheet bars is carried out either with or without binding agents.
  • sheet bars refers to somewhat porous metallic semifinished products adapted for rolling thin steel products of substantially two-dimensional extension.
  • the sheet bars are then formed to solid, rolled steel products by annealing at 600-1200 C., preferably 900- 1150 C., and rolling. These operations are repeated until the desired compression degree and dimensions are obtained.
  • the compression to single sheet bars when compared with continuous compression, includes the considerable advantage, that the subsequent treatment, for example sintering, can be divided such, that one press is served by several sintering furnaces, etc. For a continuous strand, the entire material flow fro-m the mill must be handled by one furnace. In view of the time needed for the sintering process and the carbon-oxide reaction occurring during this process, the sintering furnace must have considerable dimensions, if the production rate should be high.
  • the annealing is preferably carried out in a reducing protective gas atmosphere which may contain carburizing gases, for example carbon monoxide and/ or methane.
  • a reducing protective gas atmosphere which may contain carburizing gases, for example carbon monoxide and/ or methane.
  • carburizing gases for example carbon monoxide and/ or methane.
  • the iron ore concentrate used had the following analysis values.
  • the concentrate was reduced to spongeiron according to the Htiganas-process.
  • the sponge iron tubes obtained were cleaned.
  • the sponge iron was crushed, coarseground and pulverized in a desintegrator, whereafter the material was subjected to dry magnetic separation. These steps are represented by the areas 1a, 1b, 1c, and 1d on the drawing.
  • the iron powder had the following chemical composition.
  • the concentrate included less than 0.2% rock, exclusive of lattice-bound maganese and vanadium.
  • the iron powder after magnetic extreme concentration, was then brought to a press 2 and subjected to a pressure of about 1000 kg./cm so that its density was 3 4. At this density, the sheet bars could be handled satisfactorily.
  • the sintering as well as the substantial after-reduction were carried out in furnace 3.
  • the sintering comprised heat treatment in protective gas at relatively high temperature, in order to impart to the sheet bars such a strength, that they would withstand subsequent rolling without crack formation.
  • a further object was to remove the substantial part of iron oxides contained in the pressed iron powder sheet bars by reaction with the carbon content also contained in the sheet bars.
  • the iron powder employed contained 1.1% FeO, 0.47 F and 0.36% C.
  • the carbon-oxygen reaction commenced at about 600 C., but with a relatively low velocity. At '1000'll00 C., however, the reaction velocity was relatively high. The reaction velocity depends partially on the density of the sheet bars, in such a manner, that higher density renders a more rapid and complete reaction. The reaction was substantially not dependent on which protective gas atmosphere was used. During a furnace treatment of 15 minutes at 1050 C., the carbon content in entirely inactive argon could be reduced to 0.16% and the oxygen content (counted as FeO) to 0.4%. Experiments have proved, that mixtures containing CO and methane had an advantageous effect on the afterreduction.
  • Percent CO E the C-content for example, in the sintered sheet bars after a seven minute treatment at 1050 C. was 0.04% and the FeO-content 0.19%. By adjusting the CO and/or methane content in the protective gas, it was possible to control the C-content in the final products.
  • the .density of the sintered sheet bars was slightly above 4, and the porosity about 45%.
  • the porous sheet bars were cold rolled. This type of rolling is called compression rolling.
  • the tendency of crack formation was dependent on the tensile strength and extension properties of the sheet bars, which properties in their turn depend on the density, compression pressure and sintering temperature.
  • the risk of crack formation depends further on the relation between the thickness of the sheet bars and the roll diameter, in such a manner, that when this relation is small, i.e., with thin sheet bars and/or great roll diameter, the risk of cracks is small, even when the reduction chosen is considerable.
  • a roll diameter of 700-900 mm. is suitable in rolling mill 4 at a reduction of about 50%.
  • the sheet bars were compressed to 2.6 mm. in one pass, i.e., a reduction of 48%, no crack formation was observed.
  • the density increased from 4 to 7.1 g./cm.
  • the lateral spread was extremely low.
  • the rolling speed was low, about 0.5 m./sec.
  • the preferable temperature for the intermediate annealing depends on the conditions applied in the foregoing compression rolling. A temperature of '840" C. was found suflicient.
  • the thin sheet is desired to be delivered in strips.
  • the rolled billets must be welded together. This was performed in welding set 7. In order to prevent porosity variation in the weld, the welding was carired out after the material was almost dense. The welding was followed by a heat treatment in furnace 8.
  • the rolling of the 1.5 mm. thick welded sheets to a cold rolled product with a thickness of 0.8' mm. is preferably carried out by a series of passes with the reductions 21, 19 and 21%. This was'made in mill 9.
  • dead annealing was performed in furnace 10 at about 700 C. for about four hours at a relatively slow cooling.
  • the said annealing was followed by temper rolling with a reduction of 13% in mill 11 with large roll diameters.
  • Process for the production of rolled steel products which comprises forming a ground sponge iron. powder having a substantial content of iron oxide the bulk of which is exposed at the surfaces of the powder particles, adjusting the carbon content of said iron powder to the stoichiometric equivalent of the iron oxide content thereof by the addition of a member selected from the group consisting of pig iron and cementite, cold pressing said powder to sheet bars having a density of at least 4 g./cm. sintering said bars at a temperature of 600l200 C. whereby the oxygen and carbon contents of the bars are substantially reduced, compression rolling the sintered bars to a density of at least about 7 gm./cm. annealing the compressed rolled bars and cold rolling the annealed bars.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Metallurgy (AREA)
  • Materials Engineering (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Manufacturing & Machinery (AREA)
  • Geology (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Life Sciences & Earth Sciences (AREA)
  • Environmental & Geological Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Powder Metallurgy (AREA)
US136082A 1960-09-06 1961-09-05 Method for producing rolled steel products Expired - Lifetime US3144329A (en)

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SE3144329X 1960-09-06

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DE (1) DE1232355B (de)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3334999A (en) * 1964-02-25 1967-08-08 Mannesmann Ag Method of manufacturing semi-fabricated products of chrome-nickel steels
US3460940A (en) * 1967-03-09 1969-08-12 Charles Robert Talmage Method of producing wrought high purity steels by powder metallurgy
FR2366364A1 (fr) * 1976-02-03 1978-04-28 Cefilac Procede de fabrication de produits en acier par voie solide
JPS53112207A (en) * 1977-03-12 1978-09-30 Takaoka Kogyo Kk Production of casted iron powder sintered molded body
FR2384573A1 (fr) * 1977-03-23 1978-10-20 Davy Loewy Ltd Procede pour traiter des pastilles d'oxyde de fer purifiees, liees par un liant organique
FR2403857A1 (fr) * 1977-09-27 1979-04-20 British Steel Corp Procede de fabrication de feuillard en metal ferreux
EP0038558A1 (de) * 1980-04-21 1981-10-28 Sumitomo Electric Industries Limited Verfahren zur Herstellung von gesinterten Eisenlegierungen
US4306901A (en) * 1980-05-27 1981-12-22 Massachusetts Institute Of Technology Process for forming steel product from iron while avoiding the liquid state

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5178714A (en) * 1974-12-28 1976-07-08 Kobe Steel Ltd Kofunmatsutaino kanetsuhoho

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2222251A (en) * 1938-03-04 1940-11-19 Chrysler Corp Method of making porous metal structures and bearings
US2686118A (en) * 1952-12-23 1954-08-10 Ontario Research Foundation Method of making metal products directly from ores
US2834674A (en) * 1951-06-30 1958-05-13 Silvasy Method of making strip
CA570345A (en) * 1959-02-10 G. G. Zapf Heinz Manufacture of sintered iron bodies
US2922223A (en) * 1955-12-15 1960-01-26 Int Nickel Co Method for the production of a nonfrilled metal strip from metal powder
US2939397A (en) * 1956-12-10 1960-06-07 Kobe Inc Fluid operated multiplex pump
US2945759A (en) * 1957-09-19 1960-07-19 Gen Motors Corp Method for measuring the strength of sintered ferrous articles

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA570345A (en) * 1959-02-10 G. G. Zapf Heinz Manufacture of sintered iron bodies
US2222251A (en) * 1938-03-04 1940-11-19 Chrysler Corp Method of making porous metal structures and bearings
US2834674A (en) * 1951-06-30 1958-05-13 Silvasy Method of making strip
US2686118A (en) * 1952-12-23 1954-08-10 Ontario Research Foundation Method of making metal products directly from ores
US2922223A (en) * 1955-12-15 1960-01-26 Int Nickel Co Method for the production of a nonfrilled metal strip from metal powder
US2939397A (en) * 1956-12-10 1960-06-07 Kobe Inc Fluid operated multiplex pump
US2945759A (en) * 1957-09-19 1960-07-19 Gen Motors Corp Method for measuring the strength of sintered ferrous articles

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3334999A (en) * 1964-02-25 1967-08-08 Mannesmann Ag Method of manufacturing semi-fabricated products of chrome-nickel steels
US3460940A (en) * 1967-03-09 1969-08-12 Charles Robert Talmage Method of producing wrought high purity steels by powder metallurgy
FR2366364A1 (fr) * 1976-02-03 1978-04-28 Cefilac Procede de fabrication de produits en acier par voie solide
JPS53112207A (en) * 1977-03-12 1978-09-30 Takaoka Kogyo Kk Production of casted iron powder sintered molded body
FR2384573A1 (fr) * 1977-03-23 1978-10-20 Davy Loewy Ltd Procede pour traiter des pastilles d'oxyde de fer purifiees, liees par un liant organique
FR2403857A1 (fr) * 1977-09-27 1979-04-20 British Steel Corp Procede de fabrication de feuillard en metal ferreux
EP0038558A1 (de) * 1980-04-21 1981-10-28 Sumitomo Electric Industries Limited Verfahren zur Herstellung von gesinterten Eisenlegierungen
US4306901A (en) * 1980-05-27 1981-12-22 Massachusetts Institute Of Technology Process for forming steel product from iron while avoiding the liquid state

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Publication number Publication date
DE1232355B (de) 1967-01-12

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