钢精炼过程非金属夹杂物演变与控制  

Evolution and Control of Non-Metallic Inclusions in Steel During Secondary Refining Process

作　　者：朱苗勇 邓志银 ZHU Miaoyong;DENG Zhiyin(School of Metallurgy,Northeastern University,Shenyang 110819,China)

机构地区：[1]东北大学冶金学院,沈阳110819

出　　处：《金属学报》2022年第1期28-44,共17页Acta Metallurgica Sinica

基　　金：国家自然科学基金项目Nos.U20A20272;52074073和51804068。

摘　　要：夹杂物控制是高品质特殊钢生产的难点和重点,本文介绍了钢中夹杂物的主要类型及其在精炼过程中的生成演变及去除行为规律,并结合作者的研究与实践,阐述了夹杂物控制的关键技术。钢中夹杂物类型与最初脱氧产物有较大的区别,其生成和演变与钢中的成分元素(如Ca、Mg和Ti等)密切相关,同一组成的夹杂物在钢中形态分布不同,最终会导致评级类别的差异。精炼过程中固态夹杂物通常比液态夹杂物更容易被去除,Al_(2)O_(3)和MgO·Al_(2)O_(3)夹杂物相比液态的CaO-Al_(2)O_(3)系夹杂物具有更高的去除效率。精炼渣、耐火材料以及钢包挂渣均会对钢中微量元素控制和夹杂物演变行为产生重要影响,适宜的渣碱度和稳定的造渣操作对夹杂物的控制非常重要。铝镇静钢的精炼渣碱度控制在4~7之间即可获得较好的脱氧效果;而硅锰镇静钢精炼渣采用变碱度操作并不利于夹杂物控制。同时,应该谨慎使用含CaO耐火材料。优质的洁净合金以及适宜的合金化时机,有助于控制钢中微量元素,减少合金中夹杂物的污染。精炼过程应避免过度搅拌,减弱对钢包挂渣的冲刷,并理性考虑夹杂物变性处理。控制钢中Ca含量、避免卷渣以及尽可能排除引流砂等手段有助于控制钢中的大型夹杂物。近年来的夹杂物演变和去除机理研究解释了诸多冶金过程现象,并提出了夹杂物控制新方向,但仍有如CaO-Al_(2)O_(3)夹杂物长大机制等机理需要进一步研究揭示,也亟待开发新的夹杂物控制技术来解决诸如如何彻底消除引流砂大型夹杂物等已知问题。The problem of inclusions is one of the key concerns in the production process of high-quality special steel grades.This study summarized the main inclusion types,and their formation,evolution,and removal mechanisms during the secondary refining process.Meanwhile,combined with studies and practices of the authors,some control measures of inclusions were also discussed.According to this study,the inclusion types after refining are generally different from that of initial deoxidation products,and the formation and evolution of these inclusions are closely related to the dissolved elements in liquid steel,e.g.,Ca,Mg,and Ti.Although sometimes the compositions of the inclusions are the same,their dif-ferent shapes and distributions can also lead to different grades of inclusions depending on the micro-graphic method.Overall,solid inclusions can be easily removed compared with liquid inclusions,and Al_(2)O_(3) and MgO·Al_(2)O_(3) inclusions have a higher removal efficiency in contrast to liquid CaO-Al_(2)O_(3) system inclusions.Refining slag,refractory,and ladle glaze may have a great impact on the control of trace elements and evolution of inclusions in liquid steel;therefore,suitable slag basicity and slagging operations are important during the refining process.In the case of Al-killed steel grades,slag with a basicity of 4-7 leads to a good deoxidation result,while the slag basicity adjustment during the refining process is generally negative for the control of inclusions in Si-Mn-killed steel grades.Moreover,special attention should be given to the use of CaO-containing refractory.High-quality clean alloys and a suitable alloying stage can also be beneficial for the control of trace elements and the removal of inclusions in the alloys.Furthermore,during the refining process,excessive stirring should be avoided to reduce the flush-off of ladle glaze,and inclusion modification technologies should be considered with precautions.Some methods,e.g.,the control of Ca content,the prevention of slag entrainment,and the re

关 键 词：夹杂物 钢精炼 演变规律 去除机理 控制技术 

分 类 号：TF769[冶金工程—钢铁冶金]