重轨钢连铸大方坯V型偏析形成分析  

Analysis on the formation of V-shape segregation in rail steel bloom

作　　者：李红光 徐明丽[2] 冯元超 曾武 Li Hongguang;Xu Mingli;Feng Yuanchao;Zeng Wu(Pangang Group Research Institute Co.,Ltd.,State Key Laboratory of Vanadium and Titanium Resource Comprehensive Utilization,Panzhihua 617000,Sichuan,China;Faculty of Metallurgical and Energy Engineering,Kunming University of Science and Technology,Kunming 650093,Yunnan,China;Pangang Group Steel and Vanadium Co.,Ltd.,Panzhihua 617000,Sichuan,China)

机构地区：[1]攀钢集团攀枝花钢铁研究院有限公司,钒钛资源综合利用国家重点实验室,四川攀枝花617000 [2]昆明理工大学冶金与能源工程学院,云南昆明650093 [3]攀钢集团攀枝花钢钒有限公司,四川攀枝花617000

出　　处：《钢铁钒钛》2023年第5期180-187,共8页Iron Steel Vanadium Titanium

基　　金：国家自然科学基金(52074076)。

摘　　要：针对重轨钢连铸大方坯V型偏析,检测了V型偏析的宏观形貌特征和凝固组织,计算对比了理论收缩体积与实际V型体积。通过凝固末端压下工艺对比、钢种对比及凝固组织调控试验,探究了V型偏析形成的影响因素。结果表明,重轨钢大方坯V型偏析分两步形成,首先是凝固前沿捕捉的晶核充分长大成粗大球化等轴晶组织后发生搭接,搭接产生封闭的富集溶质微区而形成初始V型偏析,进一步在钢液静压力和凝固收缩的负压抽吸等综合作用下发生组织滑移产生中心凹陷,导致V型偏析的宏观形貌进一步改变(减小V型角)而形成最终的V型偏析。建立了协同改善重轨钢大方坯V型偏析和中心偏析的关键工艺,实现了连铸坯V型偏析和中心偏析协同改善。In order to improve V-shape segregation in rail steel bloom,the feature of macro-profile and microstructure were tested and theoretical shrinkage value and actual volume of V-shape was compared.The influencing factors including dynamic soft reduction processes,grade of steel and technology of micro-structure control were experimentally investigated.Result shows the V-shape segregation of rail steel bloom tends to form from two steps.The first step is‘initial V-shape segregation formed’where the crystal nucleus caught by solidification front of bloom fully developes into coarse connected equiaxed crystals,this results into the closed micro-regions,the molten steel in micro-regions tend to be solute rich during the solidification process.And then the second step is V-shape changed,which is formed from the microstructure subside and slip by the effect of the static pressure and the negative pressure suction due to shrinkage.Based the results the key processes has been established to improve both V-shape segregation and central segregation of rail steel bloom.

关 键 词：重轨钢 凝固组织 V型偏析 中心偏析 

分 类 号：TF76[冶金工程—钢铁冶金]