微量钛镁复合处理对低碳钢中夹杂物和组织的影响

Effect of Ti-Mg Treatment on Inclusions and Microstructure of Low Carbon Steel

对低碳钢进行钛镁复合处理,通过SEM-EDS和金相显微镜表征钢中夹杂物的特征(种类、尺寸、分布)和微观组织变化,探讨夹杂物诱导形核的可能机制。结果表明:钛镁复合处理后,钢中77%的夹杂物尺寸小于4μm,单位体积的夹杂物数量提高了48%;(Ti,Mg)Ox-MnS型复合杂物具有促进晶内铁素体形核的能力;贫Mn区是(Ti,Mg)Ox-MnS型复合夹杂物诱导晶内铁素体形核的可能机制。

The Ti-Mg treatment was carried out in low carbon steel, and its effects on inclusion（type,size, distribution） and microstructure and the possible mechanism of inclusions induced nucleation hadbeen studied by scanning electron microscopy with energy dispersive spectroscopy（SEM-EDS）, and opticalmicroscopy（OM）. It was found that after treatment, the number of inclusions per unit volume increased by48%, and the inclusions whose size is less than 4 μm accounted for 77%. Microstructure observation con-firmed intra-granular acicular ferrites which is due to the nucleation effect induced by（Ti,Mg）Ox-MnScomposite inclusions. Moreover, line scanning analysis indicated that Mn-depletion zone（MDZ） exist insteel matrix adjacent to the complex inclusion. This phenomenon can be explained by the absorption of Mnin（Ti,Mg）Ox, and this MDZ promotes the nucleation of intra-granular acicular ferrite.