LF软吹时间对硅脱氧弹簧钢氧化物夹杂控制影响  

Effect of LF soft bubbling time on oxide inclusions in Si-killed spring steel

作　　者：孟耀青 李建立[1,2] 朱航宇[1,2] 王昆鹏 MENG Yao-qing;LI Jian-li;ZHU Hang-yu;WANG Kun-peng(Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China;Hubei Provincial Key Laboratory of New Processes of Ironmaking and Steelmaking,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China;Technology Center,Zenith Steel Group Co.,Ltd.,Changzhou 213011,Jiangsu,China)

机构地区：[1]武汉科技大学钢铁冶金及资源利用省部共建教育部重点实验室,湖北武汉430081 [2]武汉科技大学钢铁冶金新工艺湖北省重点实验室,湖北武汉430081 [3]中天钢铁集团有限公司技术中心,江苏常州213011

出　　处：《钢铁》2022年第5期48-54,共7页Iron and Steel

基　　金：国家自然科学基金资助项目(51974210,52074197)。

摘　　要：对于一些采用硅锰脱氧冶炼工艺的特殊钢,为保证钢水洁净度,常会选择较长时间的LF软吹处理,导致过程能耗增加。通过工业试验,借助FEI Explorer 4自动扫描电镜检测,研究不同LF精炼软吹时间对硅脱氧弹簧钢55SiCr铸坯氧化物夹杂成分、数量的影响;并采用夹杂物极值统计法,对比评价不同LF精炼软吹时间对应成品盘条横截面最大夹杂物尺寸控制情况。结果表明,在LF软吹10 min与软吹40 min两种工艺条件下,铸坯中尺寸大于5μm的氧化物夹杂成分接近,均在CaO-SiO_(2)-Al_(2)O_(3)相图中假硅灰石、钙长石和钙铝黄长石共晶低熔点区,其中软吹10 min工艺铸坯氧化物夹杂组成落入低熔点区的数量所占比例更大。LF软吹10 min与软吹40 min铸坯中尺寸大于5μm的氧化物夹杂数量密度分别为11.70个/100 mm^(2)和14.59个/100 mm^(2),尺寸大于15μm的氧化物夹杂数量密度分别为0.53个/100 mm^(2)和1.65个/100 mm^(2),LF软吹10 min工艺铸坯大尺寸氧化物夹杂数量密度略低于LF软吹40 min工艺。当预测面积为30000 mm^(2)时,两种LF软吹时间对应成品盘条横截面最大夹杂物尺寸分别为27.1μm和28.1μm,盘条最大夹杂物尺寸控制无显著差别。结合硅锰脱氧钢中大尺寸低熔点CaO-SiO_(2)-Al_(2)O_(3)系夹杂物主要源自钢包渣乳化卷入,具有与钢水和氩气泡界面接触角很小、难以通过吹氩上浮去除的特点,建议硅锰脱氧钢LF软吹过程按短时间快节奏进行控制。In order to ensure the cleanliness of molten steel,the long-time soft bubbling during LF refining process is often chosen for some Si-Mn deoxidized special steels,resulting in increased energy consumption in the process.Based on the industrial tests,the effects of LF soft bubbling time on the composition and number density of inclusions in Si-killed spring steel bloom were investigated through a scanning electron microscope(FEI Explorer 4),and the maximum size of inclusions in the crossing section of wire rods collected from the LF process with different soft-bubbling times was compared and evaluated by the extreme-value statistical method.The results showed that for the LF processes with two soft-bubbling time,10 min and 40 min,the compositions of oxide inclusions larger than 5μm in the blooms were close,and both in the low-melting point region at the eutectic zone of pseudo-wollastonite,anorthite,and gehlenite of CaO-SiO_(2)-Al_(2)O_(3)phase diagram.The proportion of oxide inclusions falling into the low-melting point region in the 10 min soft-blowing process was higher than that in the 40 min soft-blowing process.The number densities of oxide inclusions with size larger than 5μm were 11.70/100 mm^(2) and 14.59/100 mm^(2) respectively in the blooms adopted 10 min and 40 min soft-bubbling processes.Meanwhile,the number densities of oxide inclusions with size above 15μm were 0.53/100 mm^(2) and 1.65/100 mm^(2),respectively.The number density of large oxide inclusions in the bloom of 10 min soft-bubbling process was slightly lower than that of 40 min soft-bubbling process.When the predicted area was 30000 mm^(2),the maximum sizes of oxide inclusion in the cross sections of wire rods were 27.1μm and 28.1μm respectively,and there was no significant difference of them.The low-melting point CaO-SiO_(2)-Al_(2)O_(3)inclusions with large size in Si-Mn killed steel mainly come from the emulsification of ladle slag,which had a small interface-contact angle with molten steel and argon bubble and was difficult to be rem

关 键 词：弹簧钢 硅脱氧 软吹时间 氧化物夹杂 极值统计法 接触角 

分 类 号：TF769.2[冶金工程—钢铁冶金]