(19)
(11) EP 0 338 682 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
18.09.1991 Bulletin 1991/38

(43) Date of publication A2:
25.10.1989 Bulletin 1989/43

(21) Application number: 89302878.7

(22) Date of filing: 22.03.1989
(51) International Patent Classification (IPC)4: C21D 7/02, C22F 1/00
(84) Designated Contracting States:
DE FR GB

(30) Priority: 23.03.1988 JP 67264/88

(71) Applicant: KABUSHIKI KAISHA O.C.C.
Chofu-shi Tokyo (JP)

(72) Inventor:
  • Ohno, Atsumi
    Chofu-shi Tokyo (JP)

(74) Representative: Votier, Sidney David et al
CARPMAELS & RANSFORD 43, Bloomsbury Square
London WC1A 2RA
London WC1A 2RA (GB)


(56) References cited: : 
   
       


    (54) Method of strengthening metal material and apparatus therefor


    (57) A method of strengthening a metal material of a cast product consisting of a unidirectionally solidified structure of crystals extending long in a direction of casting, and an apparatus for realizing this method. The cast product (12) is passed through a zigzag path formed by contact with circumfer­ential surfaces of rotatable rolls (16, 18, 22, 26, 28, 31), so that repeatedly bending deformation is applied to the cast product to thereby harden the cast product. The repeatedly bending deformation grows dislocation in crystals of the cast product competitively, so that free movement in dislocation of crystals cannot be made any more. As a result of the growth competition of crystals, a strengthened metal material is obtained.







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