Method and apparatus for producing high chromium content steels and/ or ferroalloys in an electric arc converter

US6068676A · kind A · utility

Assignee

• SMS Schloemann-Siemag Aktiengesellschaft · DE

Inventors

• Wei-Ping Wu · Erkrath, DE
• Karl-Heinz Deppner · Voerde, DE
• Karl-Josef Schneider · Schermbeck, DE

Key dates

• Filing date: Jun 25, 1998
• Grant date: May 30, 2000
• Expiry date: Jun 25, 2018

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P10/20
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

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.