Ca对HG785钢中Ti合金化夹杂微观组织的影响  

Ca Treatment Effect on the Evolution and Microstructure of Ti Alloyed Inclusions in HG785 Steel

作　　者：赵焕玲 Zhao Huanling(Guizhou Vocational Technology Institute,Guiyang 550023,Guizhou,China)

机构地区：[1]贵州职业技术学院,贵州贵阳550023

出　　处：《钢铁钒钛》2020年第6期142-150,共9页Iron Steel Vanadium Titanium

基　　金：贵州职业技术学院优质校建设,校企深度融合,企业实践与精品课程科研成果。

摘　　要：为了解析Ti合金化Ca处理高强钢中夹杂物演变规律及对微观组织的影响,使用扫描电镜及能谱仪分析表征其夹杂物特征及夹杂物诱导铁素体的行为,比较研究了不同类型夹杂物诱导铁素体改善微观组织的作用,并结合热力学计算,讨论了铝脱氧、Ti合金化及钙处理过程中夹杂物的演变机制。试验结果表明,随着Al、Ti、Ca合金的加入,夹杂物的成分含量发生了明显变化;随着Al脱氧时间的增加(5、10、15 min),钢中溶解氧含量降低,加Ti后,夹杂物中的Ti Ox含量也随之降低;而足够的Ca含量能使钢中高熔点夹杂物Al-Mg-Ti-O改为低熔点的液态夹杂Al-Ca-O,被还原的Ti最终残留在夹杂物中或扩散至钢液中。本研究条件下合适的Al-Ti脱氧时间间隔为10 min以上,可以提高Ti的收得率。热力学计算表明,Al2Ti O5比Al2O3更容易被Ca改性为低熔点的铝酸钙;为了避免Ca S和Ti N在液相析出,应该使[S]<0.002 4%和[N]<0.005 8%。与钢中其它类型夹杂物相比,Al-Mg-Ti-Ca-O+Mn S+Ti N更容易诱导针状铁素体析出。To reveal the inclusion evolution and its influence on the inner microstructures of high strength steel treated by Ti alloying Ca,we used scanning electron microscope and energy dispersive spectroscopy to characterize the inclusion characteristics and its induction to ferrite behaviors.We compared the effects of different types of inclusions on ferrite-induced microstructure improvement,and combined with thermodynamic calculations,discussed the evolution mechanisms of inclusions during aluminum deoxidation,Ti alloying,and calcium treatment.The experimental results show that with the addition of Al,Ti and Ca alloys,the content of inclusions have changed significantly.With the increase of deoxidation time(5 min,10min,15 min),the content of dissolved oxygen in the steel decreases.After adding Ti,the content of Ti Ox in the inclusion also decreases.Sufficient Ca content can change the high-melting inclusions of Al-Mg-TiO in the steel into the low-melting liquid inclusions of Al-Mg-Ti-O,and the reduced Ti will eventually remain in the inclusions or diffuse into the molten steel.Under the conditions of this study,the appropriate Al-Ti deoxidation time interval of is more than10 min,which can improve the yield rate of Ti.The thermodynamic calculation shows that Al2Ti O5is more easily modified by Ca into low melting calcium aluminate,rather than Al2O3.To avoid Ca S and Ti N precipitation in the liquid phase,[S]<0.002 4%and[N]<0.005 8%should be made.Compared with other types inclusions in steel,Al-Mg-Ti-Ca-O+Mn S+Ti N is more likely to induce acicular ferrite precipitation.

关 键 词：高强结构钢 钛合金化 Ca处理 夹杂物演变 针状铁素体 

分 类 号：TF76[冶金工程—钢铁冶金] TG115[金属学及工艺—物理冶金]