镁处理对Q690D钢中夹杂物的改质调控探究  

Study on modification regulation of inclusions in Q690D steel by magnesium treatment

作　　者：曹昊天 徐康 付建勋 沈平 CAO Haotian;XU Kang;FU Jianxun;SHEN Ping(Center for Advanced Solidification Technology(CAST),State Key Laboratory of Advanced Special Steel,School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China)

机构地区：[1]上海大学材料科学与工程学院,先进凝固技术中心,省部共建高品质特殊钢冶金与制备国家重点实验室,上海200444

出　　处：《冶金分析》2024年第11期9-19,共11页Metallurgical Analysis

基　　金：国家自然科学基金(52104334,51874195,52074179)。

摘　　要：Q690D钢因其较高的强度和韧性具有优异的性能,而钢中的夹杂物是影响强度和韧性的重要因素,对夹杂物的改质调控是提升产品性能的重要措施。为了探究镁对Q690D工程机械用钢中夹杂物的改质作用,采用金相显微镜、扫描电子显微镜(SEM)、夹杂物三维蚀刻仪和FactSage热力学软件对比分析了镁处理和钙处理后钢中夹杂物的分布规律及尺寸。结果表明,Q690D钢经钙处理后夹杂物主要以CaO-Al_(2)O_(3)形式存在,一部分被CaS包裹;镁处理后钢中夹杂物主要为MgO·Al_(2)O_(3)或MgO,一部分被MgS包裹。Mg可使Al2O3更加细小弥散,分布更加均匀,夹杂物平均等效直径减小,并且镁处理轧材中夹杂物数密度和面积占比分别为65 mm^(2)和0.031%,低于钙处理的96 mm^(2)和0.050%。镁处理具有更好的净化钢液和改善夹杂物尺寸和分布的作用。Q690D steel has excellent properties in strength and toughness.The inclusion in the steel is an important factor affecting the strength and toughness.The modification of inclusions is an important measure to improve the product performance.In order to investigate the modification effect of magnesium on inclusions in Q690D steel for construction machinery,the distribution pattern and size of inclusions in the steel before and after magnesium treatment were compared and analyzed using metallurgical microscopy,scanning electron microscopy,inclusion three-dimensional etcher and FactSage thermodynamic software.The results showed that the inclusions in Q690D steel after calcium treatment were mainly composed of CaO-Al_(2)O_(3),and some of them were wrapped by CaS.The inclusions in magnesium treated steel were mainly composed of MgO·Al_(2)O_(3)or MgO,and some of them were wrapped by MgS.Magnesium could make Al_(2)O_(3)finer and more uniformly distributed,and the average equivalent diameter of inclusions was reduced.The number density and area fraction of inclusions in the magnesium treated rolling stock were 65 mm^(2)and 0.031%,respectively,which were lower than those after treatment by calcium,i.e.,96 mm^(2)and 0.050%,respectively.Magnesium treatment showed better effect to purity the molten steel and improve the size and distribution of inclusions.

关 键 词：Q690D钢 高强钢 镁处理 钙处理 夹杂物 

分 类 号：TF762.1[冶金工程—钢铁冶金]