The optimization of steelmaking conditions to reduce macro inclusion for special steel

Abstract

Re-sulfurized steel grade is usually used in drive shaft and crank shaft, which is one of automotive parts, since customers require good machinability during the final processing of products. However, inclusion of spinel and CaS is formed easily in the sulfur adding steel grades, and defect rate which is caused by steelmaking problem is high in the final products. To solve this problem, the formation mechanisms of macro sized spinel and CaS inclusions were investigated. When the clogging materials are detached from the SEN, it causes not only the mold level hunting but also large sized inclusions formation. Therefore, effect of slag basicity was evaluated with different slag composition to decrease mold level hunting. In this study, we found that mold level hunting decreases as slag basicity decreases. Defect rate in the final products have decreased by one third of existing one by optimizing slag conditions. © ICS 2018 - 7th International Congress on Science and Technology of Steelmaking: The Challenge of Industry 4.0. All rights reserved.