硅锰脱氧钢中CaO-SiO_(2)-Al_(2)O_(3)夹杂在固态钢中的结晶行为  

Crystallization of CaO-SiO_(2)-Al_(2)O_(3)based inclusions in solid steel killed by Si-Mn alloys

作　　者：孟耀青 李建立[1,2] 朱航宇[1,2] 王昆鹏 王伟[4] MENG Yao-qing;LI Jian-li;ZHU Hang-yu;WANG Kun-peng;WANG Wei(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;Rolling Plant,Jiangsu Yong Gang Group Co.,Ltd.,Zhangjiagang 215628,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 [4]江苏永钢集团有限公司轧钢厂,江苏张家港215628

出　　处：《钢铁》2022年第9期65-74,共10页Iron and Steel

摘　　要：为了避免Al_(2)O_(3)、MgO·Al_(2)O_(3)等高熔点硬质夹杂物对钢材加工和产品使用性能带来危害,气门簧、切割丝用钢和手撕钢等钢种均采用了硅锰脱氧夹杂物塑性化控制工艺。夹杂物塑性化控制工艺只关注夹杂物成分是否处在相图低熔点区域是不足的,钢中硅酸盐类夹杂物之所以在非液态条件下能发生良好塑性变形,主要是因为它们具有玻璃类材料性质,其软化温度点明显低于钢材热轧温度。而硅酸盐夹杂物的热轧流变性很大程度上取决于其结晶状态,所以夹杂物从玻璃态到结晶态的转变需要予以研究和控制。从微观结构及加热软化行为方面对比了玻璃态与结晶态夹杂物的不同,指出夹杂物结晶对夹杂物塑性化控制工艺所带来的不利影响。阐明在铸坯凝固冷却和轧制前的加热过程中,玻璃态夹杂都有可能发生结晶转变。为了防止玻璃态夹杂出现严重结晶,需要结合夹杂物TTT曲线优化铸坯加热温度和时间,或控制夹杂物组成落入玻璃相更稳定区域。对于CaO-SiO_(2)-Al_(2)O_(3)体系夹杂物,认为磷石英、假硅灰石和钙长石三相共熔区是实现玻璃态稳定控制的理想组成区域。关于MgO及碱金属氧化物对硅锰脱氧钢氧化物夹杂结晶性能的影响规律需要进一步研究揭示,可以借助单丝法等方法来研究氧化物夹杂对应成分的TTT图。In order to avoid the harm of high melting point hard inclusions such as Al_(2)O_(3)and MgO·Al_(2)O_(3)to subsequent processing of steel and product service properties,inclusion plasticizing control technique by Si-Mn killed is adopted for some steels,such as valve-spring steel,saw-wire steel and the thinnest stainless steel.It is insufficient for inclusion plasticizing control technique to focus only on whether the inclusion composition is in the low melting point region of phase diagram.The good plastic deformation of silicate inclusions in steel under non-liquid condition is mainly due to their properties of glass materials,and their softening temperature is obviously lower than hot rolling temperature.The hot rolling rheology of silicate inclusions largely depends on their crystallization state,so the transition of the inclusion from glassy state to crystalline state needs to be studied and controlled.The differences between glassy and crystalline inclusions were compared in terms of microstructure and microhardness change during heating,and the adverse effects of inclusion crystallization on the inclusion plasticizing control technique were pointed out.Through industrial examples and literature reports,it was clarified that glass inclusions may undergo crystallization transformation during steel solidification and heat treatment prior to hot rolling.In order to prevent serious crystallization of glassy inclusions,it is necessary to optimize the heating temperature and time of bloom/billet by combining the TTT curve of inclusions,or controlling the inclusion composition to fall into the more stable region of glass phase.Based on the research of current scholars,it is considered that the eutectic zone of tridymite,pseudo-wollastonite and anorthite is the ideal composition region for CaO-SiO_(2)-Al_(2)O_(3)system inclusions to realize glass state stability control.The influence of magnesium oxide and alkali oxides on the crystallization properties of oxide inclusions in Si-Mn killed steel still needs to be stu

关 键 词：硅锰脱氧钢 氧化物夹杂 玻璃态夹杂 结晶 TTT图 

分 类 号：TG142.1[一般工业技术—材料科学与工程]