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:
Mar. 12, 2002
Filed:
May. 05, 2000
Andreas Peters, Düsseldorf, DE;
Meinert Meyer, Erkrath, DE;
SMS Schloemann-Siemag Aktiengesellschaft, Düsseldorf, DE;
Abstract
In a heat treatment method for producing boundary layer-hardened long products and flat products of unalloyed or low-alloy steel, the workpiece is cooled for producing a martensitic grain within a boundary layer of the workpiece by repeating several sequential cooling process steps. Each sequential cooling process step has a cooling phase, in which the workpiece is cooled to a temperature below a martensite starting temperature for martensitic conversion of only a portion of the boundary layer of the workpiece, and a temporal stress-relief phase for relieving stress within already formed martensitic grain areas and already formed martensite/austenite boundary areas. Subsequently, the workpiece is cooled at a cooling rate below a lower critical cooling rate for cooling the workpiece core.