Effect of Mg-treatment on transformation of oxide inclusions in X80 pipeline steel

作     者：Ping Shen Hao Zhang Kang Xu Shuai Liu Jin-xing Jiang Jian-xun Fu 

作者机构：Center for Advanced Solidification Technology(CAST)State Key Laboratory of Advanced Special SteelShanghai UniversityShanghai200444China Nanjing Iron and Steel Co.Ltd.Nanjing210000JiangsuChina 

出 版 物：《Journal of Iron and Steel Research International》 (钢铁研究学报（英文版）)

年 卷 期：2024年第31卷第11期

页      面：2802-2814页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：funded by the National Natural Science Foundation of China(Nos.52104334,51874195 and 52074179) Center for Advanced Solidification Technology(CAST)and State Key Laboratory of Advanced Special Steel 

主　　题：Pipeline steel Mg-treatment Ca-treatment Calcium aluminate MgO·Al_(2)O_(3) 

摘      要：In order to investigate the modification behavior and regularity of inclusions in X80 pipeline steel by Mg-treatment, the comparative industrial experiments of Mg-treatment and Ca-treatment in X80 pipeline steel were carried out. Mg and Ca were added to the steel in the form of cored wire after RH (Ruhrstahl-Hereaeus vacuum degassing) process. After adding Ca-containing cored wire, the inclusions were transformed into CaO–Al_(2)O_(3) in the steel. With the progress of smelting, the cleanliness of molten steel became worse, and the equivalent diameter of inclusions was at a higher level. Mg-treatment had a good effect on the modification of inclusions. After Mg-containing cored wire was added to the steel, Al_(2)O_(3) and CaO–Al_(2)O_(3) in the steel were transformed into MgO, MgO·Al_(2)O_(3), and CaO–MgO–Al_(2)O_(3) inclusions, which were basically spherical. The initial precipitated MgO became the core of other inclusions in the steel, which promotes the precipitation of MgO·Al_(2)O_(3). After Mg-treatment, almost no unmodified calcium aluminate inclusions existed in the hot rolled plate, and the cleanliness of the steel was improved. The effect of Ca and Mg on the transformation of inclusions in pipeline steel was studied by thermodynamic calculation, the result of which is consistent with the experimental results.