(19)
(11) EP 1 024 204 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
28.01.2004 Bulletin 2004/05

(43) Date of publication A2:
02.08.2000 Bulletin 2000/31

(21) Application number: 00101428.1

(22) Date of filing: 25.01.2000
(51) International Patent Classification (IPC)7: C21D 8/02, C22C 38/38
(84) Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
Designated Extension States:
AL LT LV MK RO SI

(30) Priority: 27.01.1999 JP 1791299

(71) Applicant: JFE Steel Corporation
Tokyo (JP)

(72) Inventors:
  • Morito, Nobuyuki, c/o Kawasaki Steel Corp.
    Kobe-shi, Okayama 712-8074 (JP)
  • Nohara, Kiyohiko, c/o Intel.Prop.Dept.
    Chiyoda-ku, Tokyo 100-0011 (JP)
  • Kobori, Katsuhiro, c/o Chiba Works
    Chiba-shi, Chiba 260-0835 (JP)
  • Nishiike, Ujihiro, c/o Intel.Prop.Dept.
    Chiyoda-ku, Tokyo 100-0011 (JP)
  • Yamashita, Takako, Tech. Res. Lab.
    Chiba-shi, Chiba 260-0835 (JP)

(74) Representative: Grünecker, Kinkeldey, Stockmair & Schwanhäusser Anwaltssozietät 
Maximilianstrasse 58
80538 München
80538 München (DE)

   


(54) Method of manufacturing a high Mn non-magnetic steel sheet for cryogenic temperature use


(57) A method of manufacturing a high Mn non-magnetic steel sheet having low permeability at a cryogenic temperature suitable for use in large scale particle accelerators, the method comprises rolling a steel material containing, on the wt% basis, from 0.05 to 0.18% of C, from 26.0 to 30.0% of Mn, from 5.0 to 10.0% of Cr, 0.05 to 0.15% of N and, optionally, from 0.50 to 5.0% of Ni, in which a rolling start temperature is from 1050 to 1200°C and a rolling end temperature is from 700 to 1000°C. Further, a cold rolled sheet is annealed at an annealing temperature for cold rolled sheet of from 1050 to 1200°C and cooled after annealing, the annealed sheet being preferably applied with temper rolling under control for the strength by varying a draft ratio.






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