Mg处理Nb-Ti微合金钢中非金属夹杂物演变机理研究  

Mechanism investigation on inclusion evolution in Nb-Ti micro-alloyed steel with Mg treatment

作　　者：朱吴杰 王德永 孙群[2] 温荣宇[2] 屈天鹏 ZHU Wujie;WANG Deyong;SUN Qun;WEN Rongyu;QU Tianpeng(Shagang School of Iron and Steel,Soochow University,Suzhou 215137,China;General Steelmaking Plant of Angang Steel Co.,Ltd.,Anshan 114021,China)

机构地区：[1]苏州大学沙钢钢铁学院,江苏苏州215137 [2]鞍钢股份有限公司炼钢总厂,辽宁鞍山114021

出　　处：《炼钢》2024年第4期40-51,共12页Steelmaking

基　　金：国家自然科学基金资助项目(52274339,52174321)。

摘　　要：在工业生产条件下,对Nb-Ti微合金钢进行Mg处理试验,分析了Mg处理条件下,微合金钢中非金属夹杂物的演变规律。结果表明,微合金钢经过铝脱氧产物主要为Al_(2)O_(3)夹杂,进行Ca处理后,Al_(2)O_(3)夹杂减少,转变为CaO-Al_(2)O_(3)夹杂,且部分MnS夹杂转变为CaS夹杂;精炼阶段将Ca处理改为Mg处理后,可将铝脱氧产物Al_(2)O_(3)夹杂变性为MgO-Al_(2)O_(3)夹杂。Mg处理前,夹杂物在LF主要是Al_(2)O_(3)夹杂,进行Mg处理和Ti合金化后,钢中主要夹杂物变为MgO-Al_(2)O_(3)夹杂、MgO夹杂和TiN夹杂,最终在铸坯中的夹杂物为MgO-Al_(2)O_(3)外包裹CaS/MnS和(Nb、Ti)N复合夹杂。对Ca处理和Mg处理的夹杂物尺寸进行对比,夹杂物尺寸主要分布在5μm以内,Mg处理形成的2μm以内的夹杂物占比高于Ca处理工艺,表明镁处理可以较好地细化夹杂物,形成大量弥散分布的细小夹杂,有助于提升钢的综合力学性能。Under industrial conditions,the Mg treatment test of Nb-Ti micro-alloyed steel was carried out.The evolution of nonmetallic inclusions in micro-alloyed steel treated with Mg was analyzed.The results show that,Al_(2)O_(3)inclusion is the main product of aluminum deoxidation in micro-alloyed steel.After Ca treatment,Al_(2)O_(3)inclusions are reduced and transformed into CaO-Al_(2)O_(3)inclusions,and part of MnS inclusions are transformed into CaS inclusions.After Ca treatment is changed to Mg treatment in the refining stage,Al_(2)O_(3)inclusions of aluminum deoxidation product can be denatalized to MgO-Al_(2)O_(3)inclusions.Before Mg treatment,the inclusions in LF are mainly Al_(2)O_(3)inclusions.After Mg treatment and Ti alloying,the main inclusions in steel become MgO-Al_(2)O_(3)inclusions,MgO inclusions and TiN inclusions.The final inclusions in the billet are MgO-Al_(2)O_(3)coated with CaS/MnS and(Nb,Ti)N complex inclusions.The size of inclusions treated with Ca and Mg was compared,and the size of inclusions mainly distributed within 5μm.The proportion of inclusions within 2μm formed by Mg treatment is higher than that by Ca treatment,which indicates that magnesium treatment can fine inclusions better.The formation of a large number of dispersed small inclusions is helpful to improve the comprehensive mechanical properties of steel.

关 键 词：Mg处理 NB-TI微合金钢 非金属夹杂物 热力学分析 

分 类 号：TF769[冶金工程—钢铁冶金]