EAF→LF→VD→CC流程SAE8620RH齿轮钢中夹杂物分析  

Analysis on inclusions of SAE8620RH gear steel produced by EAF→LF→VD→CC

作　　者：刘新 战东平 姜周华 张慧书[2] 安杰 李涛 孙大利 吴昱 LIU Xin;ZHAN Dongping;JIANG Zhouhua;ZHANG Huishu;AN Jie;LI Tao;SUN Dali;WU Yu(School of Metallurgy,Northeastern University,Shenyang 110819,China;School of Metallurgy Engineering,Liaoning Institute of Science and Technology,Benxi 117004,China;Fushun Special Steel Co.,Ltd.,Fushun 113001,China)

机构地区：[1]东北大学冶金学院,辽宁沈阳110819 [2]辽宁科技学院冶金工程学院,辽宁本溪117004 [3]抚顺特殊钢股份有限公司,辽宁抚顺113001

出　　处：《炼钢》2022年第6期58-65,共8页Steelmaking

基　　金：国家自然科学基金重点项目(51734003);中央高校基本科研业务费项目(N150204012)。

摘　　要：针对国内某钢厂采用EAF→LF→VD→CC流程生产的SAE8620RH齿轮钢中夹杂物,通过SEM-EDS和热力学计算研究了夹杂物的形成机理和演变规律。结果表明,钢中的复合夹杂物主要是以MgO·Al_(2)O_(3)为核心外部包裹CaS的复合形式存在。LF精炼初期夹杂物主要为MgO·Al_(2)O_(3),外部包裹有少量的CaS;经过钙处理后,部分MgO·Al_(2)O_(3)被改性为液态钙铝酸盐;经VD真空处理后,MgO·Al_(2)O_(3)外部包裹的CaS比例明显增加;铸坯中MgO·Al_(2)O_(3)外部重新析出MnS,形成MgO·Al_(2)O_(3)-(Ca,Mn)S。当钢液中的w(Al)=0.03%时,w(Mg)=1.85×10^(-6)就可以生成MgO·Al_(2)O_(3)。在LF精炼初期,CaS主要是[S]和[Ca]直接反应生成,而在VD真空过程中,钢液中的[S]和[Ca]会进一步反应生成CaS,并且MgO·Al_(2)O_(3)外部的钙铝酸盐也会与[S]反应形成CaS。The formation mechanism and evolution of inclusions in SAE8620RH gear steel produced by EAF→LF→VD→CC process in a domestic steel mill were studied by SEM-EDS and thermodynamic calculation.The results show that the oxygen-sulfur composite inclusions in steel mainly exist in the composite form of MgO·Al_(2)O_(3) as the core and CaS wrapped outside.The experimental results show that the inclusions in liquid steel at the early stage of LF refining are mainly MgO·Al_(2)O_(3),with a small amount of CaS wrapped around the outside.After Ca treatment,part of MgO·Al_(2)O_(3) is modified into liquid calcium aluminate.After VD vacuum treatment,the CaS proportion of MgO·Al_(2)O_(3) coating increased obviously.MgO·Al_(2)O_(3) in the billet precipitates MnS again,forms a composite form of MgO·Al_(2)O_(3)-(Ca,Mn)S.Thermodynamic calculation results show that MgO·Al_(2)O_(3) can be generated when the mass fraction of Al in liquid steel is 0.03%and the mass fraction of Mg is 1.85×10^(-6).In the early stage of LF refining,CaS is mainly generated by the direct reaction of[S]and[Ca],while in VD vacuum process,[S]and[Ca]in liquid steel will further reacted to form CaS,and calcium aluminate outside MgO·Al_(2)O_(3) will also reacted with[S]to form CaS.

关 键 词：SAE8620RH齿轮钢 夹杂物 形成机理 演变机理 

分 类 号：TF762[冶金工程—钢铁冶金]