Development of Refining Technology in Stainless Steel

Abstract

Daido Steel developed a new refining process of stainless steel, AOD-VCR (Vacuum Converter Refiner) process in Shibukawa Plant in 1989, which makes it possible to replace dilution process of AOD with vacuum process at the final stage of decarburization period and the reduction period.
At present Argon gas consumption as dilution gas occupies more than 30% of total stainless refining cost of AOD-VCR process in Chita Plant and it is important to save the consumption.
Therefore we analyzed the change of nitrogen content during AOD-VCR process and introduced nitrogen estimation formula.
The nitrogen estimation formula could optimize gas injection pattern of AOD-VCR operation and save the Ar gas consumption.