PROCESS DESCRIPTIONIn many cases, steel has not yet reached the desired quality after the refining process. Missing alloying elements, traces of interfering by-elements or dissolved gases in the melt prevent the required properties being achieved. The liquid molten steel is refined by post-treatment called "secondary metallurgy". The content of carbon, hydrogen and nitrogen is further lowered. Through alloying, setting the desired superheating level, and slagging contaminants the properties of the melt are further improved.
The most important methods of secondary metallurgy for the production of quality and stainless steel are the RH (Ruhrstahl Heraeus) process, the DH (Dortmund Hörde) process, the VD (Vacuum Degassing) process, the VOD (Vacuum-Oxygen-Decarburisation) process and the AOD (Argon-Oxygen Decarburization) process.
Improvement in steel quality
Manufacture of new steels with good performance properties
More accurate adjustment of the chemical properties of the steels