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Expired Canadian patentCanada

Method of and apparatus for heat-treating rails

CA 1259552 A · Owner: Nippon Steel Corporation · Inventors: Makino, Yoshiaki; Kageyama, Hideaki; Ishii, Mitiaki

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Abstract From the Canadian patent

A method of heat-treating a rail for obtaining a variety of strength levels from medium value to high value. The method has the steps of: preparing a steel rail maintained at a high temperature region not lower than the austenite field, and disposing a nozzle means around the head of the rail such that the nozzle means can direct a gaseous cooling medium towards the head of the rail; determining the distance between the nozzle means and the head of the rail in accordance with both the hardness level to be attained in the head of the rail and the carbon equivalent of the steel constituting the rail; moving the nozzle means such that the distance is attained between the nozzle means and the …

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Listed from its CIPO record in Patent Yard's archive of Canadian patents past their term. Its claims, description and drawings are in the CIPO record and on Google Patents, and the Claude kit works from them.

Why it's free to use

  • Granted September 19, 1989. A Canadian patent filed before October 1, 1989 lasted 17 years from grant, so its term ended September 19, 2006.
  • We check Canadian rights only. A patent in its family in another country could still be in force: check its family on Google Patents.
FiledDecember 12, 1985
GrantedSeptember 19, 1989
Term endedSeptember 19, 2006
Patent numberCA 1259552 A
Classification (IPC)C21D9/04 +2 more

Timeline

Timeline From CIPO dates

1986198919921995199820012004Application filedDec 12, 1985Patent grantedSep 19, 1989Term endedSep 19, 2006

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Everything on this page comes from the CIPO record linked above. Contains information licensed under the Open Government Licence – Canada.