The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 23, 1990
Filed:
Aug. 19, 1988
Robert J Ackert, Sault Ste. Marie, CA;
Murray A Nott, Sault Ste. Marie, CA;
Algoma Steel Corporation, Sault Ste. Marie, CA;
Abstract
An improved method for the manufacture of hardened railroad rails comprises the steps of forming a railroad rail from an alloy steel of a preselected chemical composition, force cooling the rail from a preselected cooling start temperature above about the austenite-to-ferrite transformation temperature, terminating the force cooling when the temperature of rail reaches a preselected cooling stop temperature, and before a substantial volume fraction of the austenite in the rail head has transformed to pearlite, and holding the rail under substantially isothermal conditions until the austenite-to-pearlite transformation is complete. The chemical composition of the alloy steel is selected such that the austenite-to-pearlite reaction occurs earlier in time than the austenite-to-bainite reaction under the substantially isothermal conditions. The use of this method makes avoidance of bainite easier to achieve, so relatively simple and inexpensive process control equipment can be utilized.