Patents Assigned to Avesta Sheffield Aktiebolag
  • Patent number: 6608290
    Abstract: The invention concerns heating metal strips or other coilable strand metal object to an elevated temperature, wherein the metal object is passed in a heating section through a furnace chamber that is made at least partly of an insulating and electrically non-conductive material while being heated through transverse flux induction heating (TFIH) by transverse flux induction heating elements located outside of the chamber which contains a protective non-oxidizing gas or gas mixture. The metal object is of stainless steel that has been cold rolled to a very high degree of surface reflectivity. The cold rolled stainless steel object is passed through the furnace chamber and is heated in the chamber to a processing temperature between 700 and 1200° C. The cold rolled stainless steel object is maintained at that temperature between 700 and 1200° C.
    Type: Grant
    Filed: October 4, 2001
    Date of Patent: August 19, 2003
    Assignee: Avesta Sheffield Aktiebolag
    Inventor: Philip S. Robinson
  • Patent number: 6391187
    Abstract: Method of electrolytically continuously treating a material of stainless steel at a current density of 0.1-3 A/cm2, wherein the material is passed through one or more electrolytic cells arranged in series. The cells contain an electrolyte selected from sulphuric acid, a salt thereof, phosphoric acid and nitric acid, and the material is passed through the electrolyte between electrodes arranged in series under the influence of a direct current with alternating polarity. The electrodes are arranged alternately anodic and cathodic and every electrode on one side of said material is matched by an electrode of the same polarity on an opposite side of the material, whereby an oxide surface layer with a thickness of at least 1 micrometer is removed from the material to produce a surface conditioning effect.
    Type: Grant
    Filed: July 20, 2000
    Date of Patent: May 21, 2002
    Assignee: Avesta Sheffield Aktiebolag (PUBL)
    Inventors: Anders Eklund, Malin Snis
  • Patent number: 5783000
    Abstract: A method for heat-treating steel, primarily strip-like or rod-like steel material, such as steel strip, steel sheet, steel rod or steel wire which have been rolled and heated in an oven or furnace to a surface temperature above about 900 degrees C. and thereafter cooled and optionally treated in an electrolyte bath and/or acid bath. The oven burners are fired with a liquid or a gaseous fuel which is burned with the aid of a gas that contains at least 85 percent by volume oxygen and at most 10 percent by volume nitrogen.
    Type: Grant
    Filed: September 6, 1996
    Date of Patent: July 21, 1998
    Assignees: AGA Aktiebolag, Avesta Sheffield Aktiebolag
    Inventors: Carl-Lennart Axelsson, Sten Ljungars, Lars Folke Saltin, Sven-Eric Lunner, Sten-.ANG.ke Brannvall