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:
Aug. 27, 2013
Filed:
Jan. 20, 2012
John R. Bradley, Clarkston, MI (US);
John R. Bradley, Clarkston, MI (US);
GM Global Technology Operations LLC, Detroit, MI (US);
Abstract
The microstructure of a low alloy steel workpiece for cold forming may be beneficially modified by heating the workpiece to a temperature just above its austenite transformation temperature (Actemperature). The steel workpiece is then cooled just below its Actemperature to promote ferrite formation on and between the austenite grains. Heating and cooling, above and below the Actemperature, is repeated a determined number of times to refine the austenite grains before the workpiece is quenched below its martensite transformation temperature to form a mixture of martensite with increased retained austenite. The workpiece may be further heated in its martensite region to increase the proportion of retained austenite before quenching the steel workpiece to an ambient temperature. The formability of the workpiece is improved, as is the strength of its formed shape.