PMO对42CrMoA钢ø300 mm圆坯枝晶组织的影响  

Effect of PMO on dendritic structure forø300 mm round bloom of 42CrMoA steel

作　　者：刘均 左小坦 陈永峰 刘海宁[1] 徐智帅 翟启杰[1] LIU Jun;ZUO Xiao-tan;CHEN Yong-feng;LIU Hai-ning;XU Zhi-shuai;ZHAI Qi-jie(Center for Advanced Solidification Technology,Shanghai University,Shanghai 200444,China;Steelmaking Department,Wuhu Xinxing Ductile Iron Pipes Co.,Ltd.,Wuhu 241002,Anhui,China)

机构地区：[1]上海大学先进凝固技术中心,上海200444 [2]芜湖新兴铸管有限责任公司炼钢部,安徽芜湖241002

出　　处：《中国冶金》2023年第5期53-59,共7页China Metallurgy

基　　金：国家重点研发计划资助项目(2020YFB2008400);国家自然基金重点项目(52130109)。

摘　　要：枝晶形貌是影响铸坯元素分布、缩孔缩松及性能的重要因素,细化枝晶能够有效提高铸坯质量。研究了PMO处理对42CrMoA钢ø300 mm连铸圆坯枝晶形貌的影响。研究发现,PMO处理坯的柱状枝晶生长方向发生偏转,枝晶臂间距明显减小,其中一次枝晶臂间距减小率为10%~35%,二次枝晶臂间距减小率为25%~35%。分析认为,PMO造成凝固前沿热流方向及溶质场变化,导致枝晶重新竞争生长,因此一次枝晶生长方向发生改变,且一次枝晶臂间距减小。另外,PMO在铸坯凝固前沿形成感生电流,固液相电导率差异造成枝晶尖端电流聚集,进而导致曲率半径增大,降低了细枝晶的溶解速率,抑制了二次枝晶的熟化过程,因此二次枝晶臂间距减小。研究结果为今后利用PMO改善铸坯枝晶组织提供了指导。The morphology of dendrite is an important factor affecting the solute distribution,shrinkage porosity and properties of cast bloom,and dendrite refinement can effectively improve the quality of bloom.The effect of PMO treatment on dendrite morphology ofø300 mm continuous casting round bloom of 42CrMoA steel was studied.It was found that the columnar dendritic growth direction of PMO treated bloom was deflected,and the dendrite arm spacing was significantly reduced.The primary dendrite arm spacing decreased by 10%-35%,and the secondary dendrite arm spacing decreased by 25%-35%.It is believed that the heat flow direction and solute field at the solidification front changed by PMO leads to the re-competitive growth of dendrites,so the primary dendrite growth direction changes,and the primary dendrite arm spacing decreases.In addition,PMO forms induced current at the front of solidification,and the difference of solid-liquid conductivity leads to the current accumulation at the tip of dendrite,which increases the radius of curvature,and then reduces the dissolution rate of fine dendrites,inhibits the secondary dendrite ripening process,so the secondary dendrite arm spacing decreases.The results provide guidance for improving the dendrite structure of the bloom by PMO in the future.

关 键 词：PMO 枝晶组织 连铸 圆坯 枝晶熟化 

分 类 号：TF777[冶金工程—钢铁冶金]