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:
May. 30, 2000
Filed:
Jun. 25, 1998
SMS Schloeman-Siemag Aktiengesellschaft, Dusseldorf, DE;
Abstract
A method and an apparatus for producing steels with predominantly high Cr content and/or ferro-alloys, wherein the metal charge is melted in a melting crucible, is alloyed, refined and reduced, and wherein process gases are simultaneously supplied through bottom nozzles. A melting crucible is used with a specific reaction volume of 0.4 to 1.5 m.sup.3 /t steel and the injection rates of the process gases are controlled in the range of 0.1 to 3.0 N m.sup.3 /t/min. The solid charge material is melted by an electric arc and air/nitrogen are injected simultaneously and, after forming a liquid sump, a gas mixture of oxygen and inert gas is injected. After adding slag-forming constituents and alloying agents, the oxygen throughput is increased and the power of the electric arc is reduced accordingly. The oxygen throughput is reduced in relation to the inert gas during refining and decarburization takes place as a result of increasing the electric arc with low chromium slag formation. During the reduction of the melt with suitable reduction agents, primarily chromium is reduced from the slag and silicon is bound by slag-forming constituents.