IF钢生产过程非金属夹杂物的演变行为

在DS-LD-RH-CC工艺IF钢工业生产过程系统取样和全氧含量、氮含量、非金属夹杂物形貌和化学成分检测的基础上，结合热力学分析，研究了非金属夹杂物含量、形貌与成分的演变过程.结果表明，冶炼过程钢中全氧含量逐渐降低，但需控制钢包渣氧化性以进一步降低铸坯中全氧含量；在浇铸过程中发生明显的增氮现象，应进一步加强保护浇铸，控制浇铸过程钢水增氮；在RH精炼过程中，脱氧后主要生成团簇状单一Al2O3夹杂物，Ti合金化后生成球形Al-Ti-O和内外分层的Al-Ti-Ca-Mg-O复合夹杂物；在钢水凝固过程中，生成了内层为Ti-Al-Mn-O-S、外层为TiN和AlN的复合夹杂物.在铸坯中还存在由结晶器卷渣导致的含有K，Na成分的Ti-Al-Ca-Si-Mn-O大型复合夹杂物.

Evolution of Non-metallic Inclusions During IF Steel Making Process

The evolution of content, morphology and chemical composition of non-metallic inclusions were researched based on sampling during IF (interstitial free) steel production process of the DS-LD-RH-CC route and the analysis of total oxygen content, nitrogen content, the morphology of the non-metallic inclusion and composition, combing with the thermodynamic analysis. Results showed that the total oxygen content decreased during steel smelting process, but the oxidizability of ladle slag must be controlled within lower level to further decrease the total oxygen content in the casting. Protective casting technique should be optimized to control the significant increase of the nitrogen content during continuous casting process. During the RH refining process, pure cluster Al2O3 inclusions formed after the deoxidation, spherical complex inclusions of Al-Ti-O and dual layer Al-Ti-Ca-Mg-O formed after the alloying of titanium. During the solidification of the steel, dual layer complex inclusions were formed consisting of Ti-Al-Mn-O-S core surrounded by TiN and/or AlN. Large scale complex inclusions were also existed in the casting with the main composition of Ti-Al-Ca-Si-Mn-O containing some potassium and sodium from the slag entrapment of mold fluxes.