电渣熔铸速度对金属凝固组织的影响  

Effects of Casting Velocity on Solidification Structure in Electro-slag Metal

作　　者：饶磊[1] 胡启耀[1] 李小龙[1] 耿茂鹏[1] 

机构地区：[1]南昌大学机电工程学院

出　　处：《特种铸造及有色合金》2011年第2期99-101,199,共3页Special Casting & Nonferrous Alloys

基　　金：国家高技术研究发展计划(863计划)资助项目(715-009-0110)

摘　　要：采用移动传热边界法及CAFE法,模拟了在不同熔铸速度下铸锭晶粒的生长过程以及二次枝晶臂间距的分布,进而探讨了熔铸速度对铸件凝固质量的影响。结果发现,电渣熔铸过程中,金属熔池的形状决定了柱状晶的生长方向。随着熔铸速度的增加,生长方向与熔池上升方向之间的夹角也增大,这会造成铸件力学性能的降低。二次枝晶臂间距是决定铸件冶金质量的一个重要因素,其是铸件局部冷却速度的函数。随着熔化率的增加,二次枝晶臂间距减小,这有利于减小铸件中的晶内偏析及显微缩孔的产生,从而有利于提高铸件质量。熔铸速度是电渣熔铸过程的主要控制参数,对铸件凝固质量有很大的影响,太高或太低的熔铸速度均会造成铸件凝固质量的降低。Dendrite growth direction and SDAS(secondary dendrite arm spacing)are dominant effects in controlling solidification quality of electro-slag ingot.Grain growth and distribution of SDAS in the ingot at different casting velocities were simulated by the CAFE method to understand effects on solidification quality,in which moving transfer heat was adopted.The results show that growth direction of columnar grain is controlled by melt pool shape.With increasing in casting velocity,the angular between growth direction and rising direction of melt pool is enlarged,resulting in the deterioration of mechanical properties of the alloy.SDAS is a key point for determining the quality of electro-slag castings,which is the function of partial cooling rate.With increasing in melting velocity,SDAS is decreased,which is beneficial for the decrease of grain segregation and shrinkage porosity(hole)and improvement of casting quality.Casting velocity is dominant in electro-slag process.A higher or a lower casting velocity is harmful for the casting quality.

关 键 词：电渣熔铸 速度 凝固组织 数值模拟 

分 类 号：TF141[冶金工程—冶金物理化学]