AISI431不锈钢精炼及模铸过程夹杂物演变  

Inclusion evolution in refining and mould casting process of AISI431 stainless steel

作　　者：马帅 李阳 李瑛 孙启斌 吴鹏 聂显飞 孙萌 王举 MA Shuai;LI Yang;LI Ying;SUN Qibin;WU Peng;NIE Xianfei;SUN Meng;WANG Ju(School of Metallurgy,Northeastern University,Shenyang 110819,Liaoning,China;Technology Center,Northeast Special Steel Group Co.,Ltd.,Dalian 116105,Liaoning,China;Iron and Steel Company,China Metallurgical South Engineering Technology Co.,Ltd.,Wuhan 430080,Hubei,China)

机构地区：[1]东北大学冶金学院,辽宁沈阳110819 [2]东北特殊钢集团股份有限公司技术中心,辽宁大连116105 [3]中冶南方工程技术有限公司钢铁公司,湖北武汉430080

出　　处：《钢铁》2024年第7期56-65,共10页Iron and Steel

基　　金：国家自然科学基金资助项目(52074075);教育服务东北振兴产学研用合作重点资助项目。

摘　　要：为了研究AISI 431不锈钢精炼及模铸过程的夹杂物演变规律,合理控制钢中夹杂物,以提升AISI 431探伤合格率,利用欧波同夹杂物自动分析系统OTSInca和热力学计算软件Fact Sage 8.0对国内某钢厂“EAF+AOD+LF+RH+MC”工序生产的AISI 431不锈钢精炼及模铸过程的夹杂物演变进行了分析。结果表明,RH真空处理对夹杂物的去除作用使钢中全铝T[Al]和酸溶铝Als质量分数都大幅度下降。夹杂物定量统计结果表明,钢中夹杂物成分主要以Al_(2)O_(3)为主,在成品钢中Al_(2)O_(3)质量分数更是上升到90%左右;RH真空处理后,钢中夹杂物平均直径由于铝酸钙夹杂物的碰撞聚合达到最大,这些夹杂物通过RH真空处理后的软吹大量去除,最终成品钢中夹杂物大幅降低;同时单位面积夹杂物个数在RH真空处理后达到最少的25个/mm^(2),成品钢中夹杂物数量由于二次氧化现象略有上升。通过扫描电镜观察钢中典型夹杂物形貌发现,LF前期钢中主要为大尺寸的Al-CaMg-Si-O系夹杂物,主体为Al-Ca-Mg-Si-O、部分为MgO的大尺寸夹杂,以及因铝夺取由AOD继承硅酸钙中的氧形成的铝酸钙夹杂物;RH真空处理后,钢中夹杂物主要为小尺寸的主体为Al-Ca-Mg-Si-O、部分MgO的复合夹杂物以及Al_(2)O_(3)和铝酸钙,钢中MgO·Al_(2)O_(3)夹杂因真空作用分解,MgO·Al_(2)O_(3)质量分数由RH真空处理前的21.95%降低到7.46%。Fact Sage热力学计算结果表明,LF及RH精炼后,钢中夹杂物主要为CaO·2MgO·8Al_(2)O_(3)、CaO·Al_(2)O_(3)和Spinel;相比于LF精炼,RH真空处理后Spinel相和钢中夹杂物质量分数均降低。通过对比该厂传统工艺,探伤合格率由72.5%提升到98.6%,非金属夹杂物K5(夹杂物评定标准DIN50602)为0,AISI 431不锈钢的洁净度及产品合格率均得到较好控制。To study the evolution of inclusions in AISI 431 stainless steel during refining and mold casting,control the inclusions reasonably,and improve the qualified rate of AISI 431 flaw detection,the evolution of inclusions in AISI 431 stainless steel produced in"EAF+AOD+LF+RH+MC"process was analyzed by using OTSInca and thermodynamic software FactSage 8.0.The results show that the removal of inclusions by RH vacuum treatment can greatly reduce T[Al]and Als in steel.The quantitative statistical results of inclusions show that Al_(2)O_(3) is the main component of inclusions in steel,and it increases to approximately 90%in final steel;After RH vacuum treatment,the average diameter of inclusions in steel reaches the maximum due to the collision polymerization of calcium aluminate inclusions,and these inclusions are largely removed by soft blowing after RH vacuum treatment,and the inclusions in the final steel are greatly reduced;At the same time,the number of inclusions per unit area reached the minimum of 25/mm^(2) after RH vacuum treatment,and the number of inclusions in the final steel increased slightly due to secondary oxidation.The typical morphology of inclusions in the steel was observed by scanning electron microscope.It was found that in the pre-LF steel,there were mainly large-sized Al-Ca-Mg-Si-O inclusions,mainly Al-Ca-Mg-Si-O inclusions and some MgO inclusions,and calcium aluminate inclusions formed by Al seizing O from calcium silicate inherited by AOD;After RH vacuum treatment,the inclusions in the steel are mainly small-sized composite inclusions composed of Al-Ca-Mg-Si-O partial MgO,Al_(2)O_(3) and calcium aluminate.The MgO·Al_(2)O_(3) inclusions in the steel are decomposed by vacuum and decreased from 21.95% before RH vacuum treatment to 7.46%.The results of FactSage thermodynamic calculation show that the main inclusions in the steel after LF and RH refining are CaO·2MgO·8Al_(2)O_(3),CaO·Al_(2)O_(3) and Spinel;Compared with LF refining,the mass proportion of Spinel phase and inclusions in steel decr

关 键 词：AISI 431不锈钢 LF RH 夹杂物 探伤合格率 

分 类 号：TF769[冶金工程—钢铁冶金] TF777