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(11)

EP 0 567 612 A1

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(43) Date of publication: 03.11.1993 Bulletin 1993/44 (21) Application number: 92922513.0 (22) Date of filing: 22.10.1992

(51) International Patent Classification (IPC):  C21D 8/ 12( . ) C22C 38/ 02( . ) H01F 1/ 16( . ) C22C 38/ 00( . ) C22C 38/ 16( . ) (86) International application number: PCT/KR1992/000050 (87) International publication number: WO 1993/008313 (29.04.1993 Gazette 1993/11)

(84) Designated Contracting States: DE FR GB IT (30) Priority: 22.10.1991 KR 19910018622 22.10.1991 KR 19910018626 09.10.1992 KR 19920018617 09.10.1992 KR 19920018618 09.10.1992 KR 19920018619 (71) Applicants: POHANG IRON & STEEL CO., LTD. Pohang City, Kyong Sang Book-Do 790-300 (KR) RESEARCH INSTITUTE OF INDUSTRIAL SCIENCE & TECHNOLOGY Pohang City, Kyong Sang Book-Do 790-330 (KR)

(72) Inventors: BAE, Byung, Keun Research Institute of Industrial Pohang City Kyong Sang Book-do 790-330 (KR) CHA, Sang, Yun, Research Institute of Industrial Pohang City Kyong Sang Book-do 790-330 (KR) WOO, Jong, Soo, Research Institute of Industrial Pohang City Kyong Sang Book-do 790-330 (KR) KIM, Jong, Keun, Research Institute of Industrial Pohang City Kyong Sang Book-do 790-330 (KR) KIM, Jong, Koo, Pohang Iron & Steel Co., Ltd., Kyong Sang Book-do 790 360 (KR) (74) Representative: Matschkur, Götz, Lindner Patent- und Rechtsanwälte  Postfach 11 91 09 D-90101 Nürnberg D-90101 Nürnberg (DE)