EH36钢120 t BOF-LF-RH-CC流程精炼过程中夹杂物演变研究

对采用“120tBOF-LF-RH-260mm板坯CC”工艺流程生产的EH36钢,在精炼过程中的夹杂物演变规律进行了研究。通过现场各工序取样检测,结合夹杂物形成热力学计算,分析了夹杂物种类和尺寸的变化。研究表明,在“LF→RH→中间包”的精炼过程中,钢中夹杂物数量密度呈逐渐降低趋势,而其中直径>5μm的大颗粒夹杂物数量密度则逐渐增加。大颗粒夹杂物种类为MnO-SiO₂系氧化物和CaO-Al₂O₃系钙铝酸盐,如3CaO·Al₂O₃,12CaO·Al₂O₃和CaO·Al₂O₃。在精炼过程中,当钢中Ca含量较低时,形成CaO·6Al₂O₃和CaO·2Al₂O₃,随着钢中Ca含量的升高,主要形成12CaO·7Al₂O₃和3CaO·Al₂O₃。

Research on Evolution of Inclusions in EH36 Steel during Refining Process of 120 t BOF-LF-RH-CC Flowsheet

The evolution of inclusions in the refining process of EH36 steel produced by the route of "120 t BOF-LF- RH-260 mm slab CC” has been researched. Through sampling and testing of each working procedure in situ, in combination with inclusions thermodynamic calculation, the variations of inclusion types and size are analyzed. It is found that the number density of inclusions in steel gradually decreases , but the number density of >5 μm large particle inclusions gradually increases during the refining process of MLF—>RH—>tundish". The main types of large particle inclusions are MnO- SiO₂ series oxide and CaO Al₂O₃ series calcium aluminate, such as 3 CaO·Al₂O₃, 12CaO ·Al₂O₃ and CaO?Al₂O₃. During the refining process, CaO · 6Al₂O₃ and CaO ·2Al₂O₃ are formed first when the Ca content in steel is low, and the main inclusions of 12CaO , 7Al₂O₃, 3CaO , Al₂O₃ are formed with Ca content increasing in steel.