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:
Nov. 07, 2000
Filed:
Sep. 29, 1998
Weiping Sun, Trenton, MI (US);
National Steel Corporation, Mishawaka, IN (US);
Abstract
A bake hardenable cold-rolled steel sheet and a method for producing the steel sheet are provided, wherein the steel sheet includes carbon in a range of about 0.003-0.1 wt. %, with the amount of carbon in solution being about 3-30 ppm, and the steel is substantially free of Ti, Nb, and V, which are otherwise commonly employed in producing low-carbon bake hardenable cold-rolled steel. The method includes a two stage batch or box anneal, a first stage of which is an intercritical batch anneal at a temperature between the A.sub.1 and A.sub.3 temperatures, and a second, subcritical batch anneal at a temperature below the A.sub.1 temperature and above 900.degree. F., with a slow controlled cooling from the intercritical temperature to the subcritical temperature, and from the subcritical temperature to ambient temperature.