Global Patent Index - EP 1319726 A1

EP 1319726 A1 2003-06-18 - Method of manufacturing cold rolled dual-phase microalloyed steel sheets with high strength

Title (en)

Method of manufacturing cold rolled dual-phase microalloyed steel sheets with high strength

Title (de)

Verfahren zur Herstellung von kaltgewalzten hochfesten zweiphasen-microlegierten Stahlblechen

Title (fr)

Procédé de fabrication de tôles laminées à froid à très haute résistance d'aciers dual phase micro-alliés

Publication

EP 1319726 A1 (FR)

Application

EP 02293071 A

Priority

FR 0116186 A

Abstract (en)

The fabrication of two-phase cold rolled steel sheet with a strength greater than 600 MPa consists of: <??>(a) reheating a slab to a temperature greater than 100 degrees C and less than 1250 degrees C; <??>(b) hot rolling the slab, the temperature at the end of rolling being greater than or equal to the transformation temperature Ar3; <??>(c) cooling the sheet obtained at a speed VR ≥ 10 degrees C/s; <??>(d) coiling the sheet at a temperature Tbob such that 400 degrees C ≤ Tbob ≤ 700 degrees C; <??>(e) cold rolling the sheet; <??>(f) subjecting the cold rolled sheet to a continuous annealing treatment or galvanizing treatment or aluminizing treatment. <??>The composition of the steel, by wt %, is: <??>(a) 0.05 ≤ C ≤ 0.5; <??>(b) 1 ≤ Mn ≤ 2.5; <??>(c) 0.05 ≤ Si 1.5; <??>(d) 0.01 ≤ Al ≤ 1.5; <??>(e) Cr ≤ 0.75; <??>(f) S ≤ 0.01; <??>(g) P ≤ 0.1; <??>(h) N ≤ 0.01; <??>(i) at least one alloy element chosen from Ti, Nb, Zr and V, satisfying a given relationship with N; <??>(j) the remainder being iron and production impurities. <??>The relationships between Ti, Nb, Zr and V with N are: <??>(a) 0.1 ≤ (Ti-3.4N) ≤ 0.2; <??>(b) 0.01 ≤ (Nb-6.5N) ≤ 0.15; <??>(c) 0.01 ≤ (Zr-6.5N) ≤ 0.15; <??>(d) 0.01 ≤ (Ti+Nb-3.4N) ≤ 0.35; <??>(e) 0.01 ≤ (V-3.6N) ≤ 0.20; <??>(f) 0.01 ≤ (Ti+V-3.4N) ≤ 0.40

Abstract (fr)

L'invention concerne un procédé de fabrication de tôle d'acier dual phase laminée à froid possédant une résistance supérieure à 600 MPa, dont la composition comprend (teneurs exprimées en % en poids) : 0,05% <= C <= 0,5%, 1%<= Mn <= 2,5% 0,05% <= Si <= 1,5%, 0,01% <= Al <= 1,5%, Cr <= 0,75%, S <= 0,01%, P<= 0,1%, N < 0,01 % et comportant comme élément d'alliage du titane (0,01% <= Ti -3,4N <= 0,20%) ou du zirconium (0,01 % < Zr - 6,5N < 0,15%) ou du niobium (0,01% <= Nb - 6,5N <=0,15 %) ou du vanadium ( 0,01% <= V - 3,6 N <= 0,2%), ou une combinaison de titane avec ces deux derniers éléments. Une brame d'acier de la composition ci-dessus est réchauffée à une température comprise entre 1000 et 1250°C, laminée jusqu'à une température supérieure ou égale à Ar3, puis la tôle est refroidie à une vitesse VR>=10°C/s, bobinée à une température comprise entre 400 et 700°C. Après laminage à froid, on effectue un recuit à une température comprise entre Ac1 et 810°, suivi d'un refroidissement dont la vitesse est supérieure à 2°C/s.

IPC 1-7 (main, further and additional classification)

C21D 8/02; C22C 38/02; C22C 38/04; C22C 38/12; C22C 38/14

IPC 8 full level (invention and additional information)

C21D 8/02 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/12 (2006.01); C22C 38/14 (2006.01)

CPC (invention and additional information)

C22C 38/001 (2013.01); C21D 8/0273 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/12 (2013.01); C22C 38/14 (2013.01); C21D 8/0226 (2013.01); C21D 8/0236 (2013.01)

Citation (search report)

Designated contracting state (EPC)

AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LI LU MC NL PT SE SI SK TR

EPO simple patent family

EP 1319726 A1 20030618; FR 2833617 A1 20030620; FR 2833617 B1 20040820

INPADOC legal status


2017-07-19 [18D] APPLICATION DEEMED TO BE WITHDRAWN

- Effective date: 20170217

2016-03-16 [RAP1] TRANSFER OF RIGHTS OF AN APPLICATION

- Owner name: ARCELORMITTAL

2010-09-01 [17Q] FIRST EXAMINATION REPORT

- Effective date: 20100730

2006-06-14 [RAP1] TRANSFER OF RIGHTS OF AN APPLICATION

- Owner name: ARCELOR FRANCE

2004-03-10 [AKX] PAYMENT OF DESIGNATION FEES

- Designated State(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LI LU MC NL PT SE SI SK TR

2004-03-03 [17P] REQUEST FOR EXAMINATION FILED

- Effective date: 20031218

2003-06-25 [RIN1] INVENTOR CHANGED BEFORE GRANT

- Inventor name: MOULIN, ANTOINE

2003-06-25 [RIN1] INVENTOR CHANGED BEFORE GRANT

- Inventor name: CHRISTEN, JEAN-LUC

2003-06-25 [RIN1] INVENTOR CHANGED BEFORE GRANT

- Inventor name: FARAL, ODILE

2003-06-18 [AK] DESIGNATED CONTRACTING STATES:

- Designated State(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR IE IT LI LU MC NL PT SE SI SK TR

2003-06-18 [AX] REQUEST FOR EXTENSION OF THE EUROPEAN PATENT TO:

- Countries: AL LT LV MK RO