Combined acid-basic open hearth steel making process - where charge is melted under acid deoxidising slag, which is then replaced by basic slag

摘要

A basic open hearth furnace is used, in which the scrap charge includes enough Mn and Si, pref. in the form of Mn ore, Fe-Mn, and Fe-Si or sand, so that strong deoxidn. of the melt commences immediately. The inlet slag has a KMn value of 0.1-0.3 in (I) when the Mn content of the steel is >0.6%. The slag is then removed, and lime is added to form a basic slag for conventional basic steel making for completion of the process. KMn = FeSlag x MnSteel/MnSlag (I) This combined process improves the quality of the steel obtd.