Patents Assigned to Avestapolarit AB
  • Publication number: 20050211347
    Abstract: A method for manufacturing an ultra-high-tensile sheet method product of steel, at which the initial work piece used is constituted of a metal work piece of iron, alloyed with chromium, nickel and carbon in predetermined proportions. The initial work piece is wholly or partially plastically cold worked by stretch forming or stretch bending at a predetermined temperature and/or deformation degree, that determines and is determining for the yield point of the final product, in providing a strong deformation hardening, that gives the final product a totally or partially many times increased strength or higher yield point, as compared to the yield point of the initial work piece.
    Type: Application
    Filed: March 13, 2003
    Publication date: September 29, 2005
    Applicant: AvestaPolarit AB
    Inventors: Leif Carlsso, Hans Groth
  • Patent number: 6868708
    Abstract: The invention relates to workpiece control shaping of metal, preferably in the form of plates or bands, which metal workpiece has a high tensile limit, preferably about 1000 N/mm2, and is intended to be further shaped. Along predetermined folding notches or zones across the workpiece, the tensile limit of the material is reduced by heating to a tensile limit, which is substantially lower than that of adjacent base material, and when the workpiece has cooled it is subjected to subsequent bending, folding, or shaping operations to provide a two- or three-dimensional shape/extension of the workpiece along the treated folding notches or zones.
    Type: Grant
    Filed: February 22, 2001
    Date of Patent: March 22, 2005
    Assignee: Avestapolarit AB
    Inventors: Leif Carlsson, Hans Groth
  • Patent number: 6546771
    Abstract: The invention relates to a method for the manufacturing of strips of stainless steel, comprising cold rolling of a strip which in a foregoing process has been manufactured through casting a melt to form a cast strip and/or has been hot rolled. The cold rolling is performed in a rolling mill line (B), which comprises, in the initial part of the line, at least two initial cold rolling mills (11-13) in series, after said initial cold rolling mills at least one annealing furnace (18) and at least one pickling section (26, 27), and in a terminating part of the line, at least one more cold rolling mill (32). The patent specification discloses various modes of operation, including passing the strip once or twice through the line.
    Type: Grant
    Filed: July 10, 2001
    Date of Patent: April 15, 2003
    Assignee: Avestapolarit AB
    Inventor: Sten Ljungars
  • Patent number: 6537398
    Abstract: A strip of stainless steel, which is cast and/or hot rolled and which is dark colored by oxides on the surface of the strip, remaining from the foregoing manufacture of said cast and/or hot rolled strips, is cold rolled in one or more cold rolling passes (11-13) following after each other, so that the thickness of the strip is reduced by 10-75% and so that the oxide scales crackle, i.e. so that fissures are established in the oxide layers. Thereafter, the strip is annealed in a furnace (18) having a furnace atmosphere obtainable by heating the furnace by means of burners which consume a liquid or gaseous fuel, which is combusted by means of a gas which contains at least 85 vol-% oxygen and not more than 10 vol-% nitrogen, wherein a furnace atmosphere is created, in which the strip can be annealed without oxidising the metal surfaces which are exposed through the crackling, in a way which would make the subsequent descaling and pickling difficult.
    Type: Grant
    Filed: July 10, 2001
    Date of Patent: March 25, 2003
    Assignee: AvestaPolarit AB (publ)
    Inventor: Sten Ljungars