EP1337362A1 - Procede de production de bandes d'acier - Google Patents

Procede de production de bandes d'acier

Info

Publication number
EP1337362A1
EP1337362A1 EP01971503A EP01971503A EP1337362A1 EP 1337362 A1 EP1337362 A1 EP 1337362A1 EP 01971503 A EP01971503 A EP 01971503A EP 01971503 A EP01971503 A EP 01971503A EP 1337362 A1 EP1337362 A1 EP 1337362A1
Authority
EP
European Patent Office
Prior art keywords
strip
steel
cast
microstructure
residuals
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
EP01971503A
Other languages
German (de)
English (en)
Other versions
EP1337362A4 (fr
Inventor
Lazar Strezov
Kannappar Mukunthan
Walter Blejde
Rama Mahapatra
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nucor Corp
Original Assignee
Nucor Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nucor Corp filed Critical Nucor Corp
Publication of EP1337362A1 publication Critical patent/EP1337362A1/fr
Publication of EP1337362A4 publication Critical patent/EP1337362A4/fr
Ceased legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/16—Controlling or regulating processes or operations
    • B22D11/22—Controlling or regulating processes or operations for cooling cast stock or mould
    • B22D11/225—Controlling or regulating processes or operations for cooling cast stock or mould for secondary cooling
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
    • B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
    • B22D11/06—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars
    • B22D11/0622—Continuous casting of metals, i.e. casting in indefinite lengths into moulds with travelling walls, e.g. with rolls, plates, belts, caterpillars formed by two casting wheels
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/021—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips involving particular fabrication steps or treatments of ingots or slabs
    • C21D8/0215—Rapid solidification; Thin strip casting
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
    • C21D9/52—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for wires; for strips ; for rods of unlimited length
    • C21D9/54—Furnaces for treating strips or wire
    • C21D9/56—Continuous furnaces for strip or wire
    • C21D9/573—Continuous furnaces for strip or wire with cooling

Definitions

  • the present invention relates to a method of producing steel strip and the cast strip produced according to the method.
  • the present invention relates to producing steel strip in a continuous strip caster.
  • strip as used in the specification is to be understood to mean a product of 5mm thickness or less.
  • casting steel strip continuously in a twin roll caster involves introducing molten steel between a pair of contra-rotated horizontal casting rolls which are internally water cooled so that metal shells solidify on the moving rolls surfaces and are brought together at the nip between them to produce a solidified strip delivered downwardly from the nip between the rolls, the term "nip" being used to refer to the general region at which the rolls are closest together.
  • the molten metal may be poured from a ladle into a smaller vessel from which it flows through a metal delivery nozzle located above the nip so as to direct it into the nip between the rolls, so forming a casting pool of molten metal supported on the casting surfaces of the rolls immediately above the nip and extending along the length of the nip.
  • This casting pool is usually confined between side plates or dams held in sliding engagement with end surfaces of the rolls so as to dam the two ends of the casting pool against outflow, although alternative means such as electromagnetic barriers have also been proposed.
  • the casting of steel strip in twin roll casters of this kind is for example described in United States Patents 5,184,668, 5,277,243 and 5,934,359.
  • the concentration of residuals in the steel composition can have a significant effect on the finished microstructure, and in turn affect yield strength properties of cast strip.
  • higher concentrations of residuals make it possible to use lower cooling rates to transform the strip from austenite to ferrite in a temperature range between 850°C and 400°C to produce microstructures in cast strip that provide high yield strengths - It is understood that the transformation temperature range is within the range between 850°C and
  • the continuous caster may be a twin roll caster.
  • residuals covers levels of elements, such as copper, tin, zinc, nickel, chromium, and molybdenum, that are included in relatively small amounts, and are usually as a consequence of standard steel making.
  • the elements may be present as a result of using scrap steel to produce steel.
  • the total amount of the residuals is 1.2 wt°6 or less. These residuals may be up to 2.0 wt% where harder steel strip is desired with yield strengths up to and in excess of 700 MPa. This weight percent is the total weight percent in the steel strip including the residuals from scrap steel and steel processing.
  • the cast strip produced in step (a) may have a thickness of no more than 2mm.
  • the cast strip produced in step (a) may include austenite grains that are columnar.
  • the steel may be low carbon steel.
  • low carbon steel is understood to be mean steel of the following composition, in wt%:
  • Mn 1 .0 or less ; residuals: 1.2 or less; and Fe: balance.
  • the low carbon steel may be silicon/manganese killed and may have the following composition by weight:
  • the low carbon steel may be aluminum killed and may have the following composition by weight:
  • the aluminum killed steel may be calcium treated.
  • the method may further include the step of inline hot rolling the cast strip after step (a) and prior to step (b) .
  • Step (b) may include cooling the strip to transform the strip from the austenite to ferrite at a selected cooling rate of at least 0.01°C/sec, and usually at least 0.1 °C/sec, to produce a microstru ⁇ ture that provides required yield strength properties of the cast strip, the microstru ⁇ ture being selected from a group that includes microstructures that are:
  • microstructures of types (ii) and (iii) will have microstructures of types (ii) and (iii) .
  • low temperature transformation products includes idmanstatten ferrite, acicular ferrite, bainite, and martensite.
  • Figure 1 illustrates a strip casting installation incorporating an in-line hot rolling mill and coiler
  • Figure 2 illustrates details of the twin roll strip caster
  • Figure 3 illustrates the effect of residuals on yield strength of cast strip.
  • twin roll casters The following description is in the context of continuous casting steel strip using a twin roll caster.
  • the present invention is not limited to the use of twin roll casters and extends to other types of continuous strip casters.
  • Figure 1 illustrates successive parts of a production line whereby steel strip can be produced in accordance with the present invention.
  • Figures 1 and 2 illustrate a twin roll caster denoted generally as 11 which produces a cast steel strip 12 that passes in a transit path 10 across a guide table 13 to a pinch roll stand 14 comprising pinch rolls 14A.
  • the strip passes into a hot rolling mill 16 comprising a pair of reduction rolls 16A and backing rolls 16B by in which it is hot rolled to reduce its thickness .
  • the rolled strip passes onto a runout table 17 on which it may be force cooled by water jets 18 and through a pinch roll stand 20 comprising a pair of pinch rolls 20A, and thence to a coiler 19.
  • twin roll caster 11 comprises a main machine frame 21 which supports a pair of parallel casting rolls 22 having a casting surfaces 22A.
  • Molten metal is supplied during a casting operation from a ladle (not shown) to a tundish 23, through a refractory shroud 24 to a distributor 25 and thence through a metal delivery nozzle 26 into the nip 27 between the casting rolls 22.
  • Molten metal thus delivered to the nip 27 forms a pool 30 above the nip and this pool is confined at the ends of the rolls by a pair of side closure dams or plates 28 which are applied to the ends of the rolls by a pair of thrusters (not shown) comprising hydraulic cylinder units connected to the side plate holders.
  • the upper surface of pool 30 (generally referred to as the "meniscus" level) may rise above the lower end of the delivery nozzle so that the lower end of the delivery nozzle is immersed within this pool .
  • Casting rolls 22 are water cooled so that shells solidify on the moving roll surfaces and are brought together at the nip 27 between them to produce the solidified strip 12 which is delivered downwardly from the nip between the rolls.
  • twin roll caster may be of the kind which is illustrated and described in some detail in United States Patents 5,184,668 and 5,277,243 or United States Patent 5,488,988 and reference may be made to those patents for appropriate constructional details which form no part of the present invention.
  • the cooling rate in transforming the strip from austenite to ferrite in a temperature range between 850°C and 400°C is selected to be at least 0.01°C/sec, preferably at least 0.1°C/sec, and may be in excess of 100°C/sec. With such cooling rates for low carbon steel it is possible to produce cast strip having microstructures including:
  • the concentration of residuals in the steel is selected having regard to the finished microstructure of the cast strip that is required to provide required mechanical properties for the strip.
  • the present disclosure is based on experimental work that has found the presence of a high amount of residuals (0.2%Cr, 0.2%Ni, 0.2%Mo, 0.4%Cu, 0.2%Sn) has produced a strip with improved microstructure.
  • the experimental findings include that the austenite microstructure of strip cast at 75 m/min was similar to the microstructure of strip without residuals. However, when the cast strip with residuals was subjected to a standard cooling rate of 10-15°C/sec, the resultant finished microstructure was very different from that of the cast strip without residuals cooled at the same rate.
  • the observed microstructure of cooled cast strip with residuals was predominantly bainitic with only a thin band of grain boundary ferrite appearing along the prior austenite grain boundaries, indicating a severely suppressed ferrite transformation caused by the presence of residuals.
  • the mechanical properties of the resultant product are very desirable, with typical values of 540 MPa yield strength, 650 MPa tensile strength and 15% total elongation. Such values could be achieved in the past by icroalloying which added considerable cost to the production of the cast strip.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Continuous Casting (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
  • Metal Rolling (AREA)

Abstract

L'invention concerne des bandes d'acier et leurs procédés de production. Selon un mode de réalisation, ce procédé consiste à couler de l'acier fondu en bande de manière continue, l'acier fondu constitué d'une concentration de résidus de 2,0 % en poids ou moins étant sélectionné par rapport à la microstructure de la bande finie afin d'obtenir une résistance au fléchissement désirée; et à refroidir ladite bande de façon à obtenir une transformation austénite-ferrite dans une plage de températures comprise entre 850 °C et 400 °C. L'invention concerne également l'acier coulé doté de propriétés de résistance au fléchissement améliorées produit à l'aide de ce procédé.
EP01971503A 2000-10-02 2001-09-28 Procede de production de bandes d'acier Ceased EP1337362A4 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
AUPR046000 2000-10-02
AUPR0460A AUPR046000A0 (en) 2000-10-02 2000-10-02 A method of producing steel strip
PCT/AU2001/001224 WO2002028569A1 (fr) 2000-10-02 2001-09-28 Procede de production de bandes d'acier

Publications (2)

Publication Number Publication Date
EP1337362A1 true EP1337362A1 (fr) 2003-08-27
EP1337362A4 EP1337362A4 (fr) 2004-11-03

Family

ID=3824520

Family Applications (1)

Application Number Title Priority Date Filing Date
EP01971503A Ceased EP1337362A4 (fr) 2000-10-02 2001-09-28 Procede de production de bandes d'acier

Country Status (13)

Country Link
US (1) US20020043304A1 (fr)
EP (1) EP1337362A4 (fr)
JP (1) JP2004509770A (fr)
KR (2) KR20090011018A (fr)
CN (1) CN1466503A (fr)
AU (1) AUPR046000A0 (fr)
BR (1) BR0114404A (fr)
CA (1) CA2422133A1 (fr)
MX (1) MXPA03002806A (fr)
MY (1) MY134909A (fr)
RU (1) RU2307002C2 (fr)
TW (1) TW520307B (fr)
WO (1) WO2002028569A1 (fr)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AUPP811399A0 (en) * 1999-01-12 1999-02-04 Bhp Steel (Jla) Pty Limited Cold rolled steel
US7117925B2 (en) * 2000-09-29 2006-10-10 Nucor Corporation Production of thin steel strip
US7485196B2 (en) * 2001-09-14 2009-02-03 Nucor Corporation Steel product with a high austenite grain coarsening temperature
US7938164B2 (en) 2002-06-04 2011-05-10 Nucor Corporation Production of thin steel strip
US7404431B2 (en) 2002-06-04 2008-07-29 Nucor Corporation Production of thin steel strip
JP4197269B2 (ja) * 2002-09-09 2008-12-17 株式会社キッツ バルブ・管継手等の銅合金製配管器材のニッケル溶出防止法及びその銅合金製配管器材
WO2007079545A1 (fr) * 2006-01-16 2007-07-19 Nucor Corporation Bande d'acier coulé mince à microfissuration réduite
US7975754B2 (en) * 2007-08-13 2011-07-12 Nucor Corporation Thin cast steel strip with reduced microcracking
HUP1300743A2 (hu) 2013-12-19 2015-06-29 Dunaujvarosi Foeiskola Technikai elrendezés és egységes elven alapuló eljárás többes fázisú és TRIP-acélok szabályozott hõmérsékletvezetésû meleghengerléssel történõ elõállítására

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ATE81042T1 (de) * 1988-07-14 1992-10-15 Thyssen Stahl Ag Verfahren zum herstellen eines stahlbandes mit einer dicke von weniger als 10 mm.
JP2768807B2 (ja) * 1990-02-06 1998-06-25 新日本製鐵株式会社 薄帯鋼板の製造方法
EP0641867A4 (fr) * 1993-02-26 1995-06-07 Nippon Steel Corp Piece mince moule en acier au carbone ordinaire contenant des quantites importantes de cuivre et d'etain, tole mince en acier et procede de fabrication.
JPH07118735A (ja) * 1993-10-20 1995-05-09 Nippon Steel Corp 薄肉帯状鋳片の製造方法及び装置
WO1995013155A1 (fr) * 1993-11-08 1995-05-18 Ishikawajima-Harima Heavy Industries Company Limited Traitement thermique en ligne d'un feuillard d'acier coule en continu
KR100187553B1 (ko) * 1994-03-25 1999-06-01 다나카 미노루 박판주조스트립의 제조방법
KR100205191B1 (ko) * 1994-04-04 1999-07-01 아사무라 다까시 쌍로울식 연속주조법 및 장치
JP2792834B2 (ja) * 1995-04-18 1998-09-03 新日本製鐵株式会社 薄鋳帯からの強度５００ＭＰａ 以下の炭素鋼薄鋼帯の製造方法
RU2095461C1 (ru) * 1996-02-14 1997-11-10 Тарасов Виктор Алексеевич Сталь
SK286108B6 (sk) * 1996-12-19 2008-03-05 Corus Staal B.V. Spôsob výroby oceľového pásu alebo plechu
IT1290743B1 (it) * 1997-04-10 1998-12-10 Danieli Off Mecc Procedimento di laminazione per prodotti piani con spessori sottili e relativa linea di laminazione
IT1291931B1 (it) * 1997-06-19 1999-01-21 Voest Alpine Ind Anlagen Procedimento per la produzione di nastri grezzi di colaggio in acciaio a basso contenuto di carbonio e nastri cosi' ottenibili
GB9803409D0 (en) * 1998-02-19 1998-04-15 Kvaerner Metals Davy Ltd Method and apparatus for the manufacture of light gauge steel strip
JPH11269600A (ja) * 1998-03-25 1999-10-05 Daido Steel Co Ltd 熱間鍛造用高靱性非調質鋼
FR2798871B1 (fr) * 1999-09-24 2001-11-02 Usinor Procede de fabrication de bandes d'acier au carbone, notamment d'acier pour emballages, et bandes ainsi produites

Also Published As

Publication number Publication date
KR20030064762A (ko) 2003-08-02
WO2002028569A1 (fr) 2002-04-11
JP2004509770A (ja) 2004-04-02
US20020043304A1 (en) 2002-04-18
RU2307002C2 (ru) 2007-09-27
BR0114404A (pt) 2003-07-29
EP1337362A4 (fr) 2004-11-03
MXPA03002806A (es) 2004-09-10
TW520307B (en) 2003-02-11
KR20090011018A (ko) 2009-01-30
CA2422133A1 (fr) 2002-04-11
MY134909A (en) 2007-12-31
CN1466503A (zh) 2004-01-07
AUPR046000A0 (en) 2000-10-26

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