Application of the Oxygen Sensor for Stainless Steel Melting

In terms of stainless steel manufacturing process with EAF (Electric Arc Furnace) and AOD-VCR (Vacuum Converter Refiner), it is important to control the chemical composition, especially [%Si], after tapping because of the following reason. 1) The less [%Si] after tapping is, the less the EAF yield is because of [Fe] oxidation during EAF process. 2) The more [%Si] after tapping is, the longer the AOD-VCR treatment time is because of decreasing decarburization efficiency. 3) As the 2) result, the gas consumption during AOD-VCR process is increasing, and AOD vessel life is decreasing. To solve the above problems, Daido Steel Chita Plant has utilized the oxygen sensor consists of the solid electrolyte, which makes it possible to estimate [%Si] before tapping, judging from the oxygen activity during melting depends on the calculation results with molten steel temperature and electromotive force which has occurred in the solid electrolyte. And so, the cost and yield in stainless stee l is improved as a result of precise control of [%Si] after tapping by the oxygen sensor application.