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.

Date of Patent:
Sep. 10, 1996

Filed:

Jun. 06, 1995
Applicant:
Inventors:

William E Heitmann, Crown Point, IN (US);

Birchel S Brown, Apollo Beach, FL (US);

Assignee:

Inland Steel Company, Chicago, IL (US);

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
C21D / ; C22C / ; C22C / ;
U.S. Cl.
CPC ...
148330 ; 148334 ; 148602 ; 148654 ;
Abstract

A billet of steel has a composition comprising small amounts of hardenability agents. The billet is hot rolled into a continuous bar, in two hot rolling stages with an intervening cooling step employing a turbulent cooling liquid. After the second hot rolling stage, the bar is gathered into a succession of closely overlaying loops and moved along a roller conveyor where the overlapping loops are cooled by air blowers, after which the bar is coiled. The resulting hot rolled bar has a microstincture consisting essentially of bainite in fine-sized packets reflecting an average austenitic grain size, before the gathering and cooling steps, of 8-11 ASTM. A threaded fastener in its final form can be produced from the hot rolled bar by a cold deforming operation without a heat treating operation before or after cold deforming. The threaded fastener is undistorted and contains residual compressive stresses.


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