外加镁系氧化物粒子在钢铁材料制备中的进展  

Progress of adding magnesium oxide particles in preparation of iron and steel materials

作　　者：鸡永帅 李阳 姜周华 孙萌 马彦硕 JI Yong-shuai;LI Yang;JIANG Zhou-hua;SUN Meng;MA Yan-shuo(School of Metallurgy,Northeastern University,Shenyang 110819,Liaoning,China)

机构地区：[1]东北大学冶金学院,辽宁沈阳110819

出　　处：《中国冶金》2023年第2期8-21,共14页China Metallurgy

基　　金：国家自然科学基金资助项目(52074075)。

摘　　要：镁系氧化物粒子(MgO和MgO·Al_(2)O_(3))在钢液中具有良好的分布特征,在适当的条件下向钢液加入镁系氧化物粒子可以改性和细化夹杂物、细化奥氏体晶粒和诱导晶内铁素体形核,最终实现钢材性能的优化。从镁系氧化物粒子的加入方法、对夹杂物的影响、对奥氏体晶粒的钉扎作用、诱导铁素体形核机理、对力学性能的影响5个方面进行总结。结果表明,降低密度差和润湿角粒子或结合强反应元素有利于提高收得率,粉末预分散法结合外场搅拌有利于进一步提升粒子在钢液中的均匀性;合理的镁系氧化物粒子加入量(质量分数)为0.01%~0.03%,夹杂物平均尺寸控制在1~2μm,可以将夹杂物改性为MgO·Al_(2)O_(3)或MgS;外加镁系氧化物有利于细化奥氏体晶粒、改善硫化物分布和提高针状铁素体比例,当其加入量为0.05%时,针状铁素体联锁最优,奥氏体晶粒最小;当超微镁系氧化物粒子的加入量为0.05%左右时钢铁材料的力学性能最优,屈服强度、抗拉强度、冲击韧性显著提高。Magnesium oxide particles(MgO and MgO·Al_(2)O_(3))have good distribution characteristics in molten steel.Under appropriate conditions,adding magnesium oxide particles to molten steel can modify and refine inclusions,refine austenite grains and induce intragranular ferrite nucleation,and ultimately achieve the optimization of steel properties.The addition method of magnesium oxide particles,influence on inclusions,pinning effect on austenite grains,nucleation mechanism of induced ferrite and the influence on mechanical properties are summarized.The results show that the decreasing density difference and wetting angle particles or combination of strong reaction elements are conducive to improving the yield,and the powder pre-dispersion method combined with field stirring is conducive to further improving the uniformity of particles in molten steel.The reasonable addition amount(mass fraction)of magnesium oxide particles is 0.01%-0.03%,and the average size of inclusions is controlled at 1-2μm,then the inclusions can be modified into MgO·Al_(2)O_(3)or MgS.The addition of magnesium oxide is conducive to refining austenite grains,improving sulfide distribution and increasing the proportion of acicular ferrite.When the addition amount is 0.05%,the interlocking of acicular ferrite is optimal,and the austenite grains are minimum.When the addition amount of ultrafine magnesium oxide particles is about 0.05%,the mechanical properties of steel materials are optimal,the yield strength,tensile strength and impact toughness are significantly improved.

关 键 词：镁系氧化物 强化 晶粒生长 针状铁素体 钢铁材料 

分 类 号：TF702[冶金工程—钢铁冶金]