Patents Issued in January 29, 1970
  • Patent number: 4186034
    Abstract: The present invention resides in the manufacture of an AlMg alloy sheet with zinc addition which is readily deformable in the soft condition and especially suited for shaping into motor vehicle body components. The alloy sheet has a strength of at least 250 N/mm.sup.2, a grain size of less than 50 .mu.m and, after deformation has occurred, remains free of surface defects such as orange peel effect and Luders bands and also, after a possible influence of heat, remains insensitive to stress corrosion cracking. The zinc addition produces a widening of the working range so that after the last cold rolling operation the alloy can be soft annealed above the recrystallization temperature without coarse grains or Luders band appearing. The zinc addition produces an insensitivity with respect to stress corrosion cracking after a heterogenization annealing subsequent to the soft annealing, even after a sensitization at 150.degree. C. on a sheet which has been deformed with a cold reduction of 20% and more.
    Type: Grant
    Filed: December 6, 1978
    Date of Patent: January 29, 1970
    Assignee: Swiss Aluminium Ltd.
    Inventor: Rudolf Akeret