CAFE模型机理及应用

第21卷第10期

2009年10月

钢铁研究学报 Journal of Iron and Steel Research

Vol.21,No.10October 2009

基金项目:国家自然科学基金资助项目(50874007)

作者简介:王金龙(19782),男,博士生,讲师; E 2m ail :wangjlong78@ ; 修订日期:2009204216

CAFE 模型机理及应用

王金龙1,　赖朝彬1,2,　王福明1,　张炯明1,　任　嵬1

(1.北京科技大学冶金与生态工程学院,北京100083;　2.新余钢铁公司,江西新余338001)

摘　要:分析了CA FE 法模拟凝固过程微观组织的物理本质、数值计算方法,并应用CA FE 法模拟了易切削钢

9SMn28的三维微观组织,优化了9SMn28的成分。在CA FE 模型中,形核密度用高斯分布来描述;枝晶尖端生

长动力学用KGT 模型进行计算;枝晶生长的择优取向是<100>方向,并可实现枝晶生长的竞争机制;FE 与CA 耦合是通过FE 节点和CA 元胞之间的插值实现的。易切削钢9SMn28微观组织模拟结果与实验吻合较好,确定的碳、磷、锰、硅、硫的最佳质量分数分别为0115%、0110%、112%、0108%、0136%,并对优化结果进行了模拟,有效地改善了9SMn28的凝固组织。

关键词:元胞自动机2有限元模型;模拟;微观组织

中图分类号:T G 142 文献标识码:A 文章编号:100120963(2009)1020060204

Mechanism and Application of CAFE Method

WAN G Jin 2long 1,　L A I Chao 2bin 1,2,　WAN G Fu 2ming 1,　ZHAN G Jiong 2ming 1,　REN Wei 1

(1.School of Metallurgical and Ecological Engineering ,University of Science and Technology Beijing ,Beijing 100083,China ;　2.Xinyu Iron and Steel Co ,Xinyu 338001,Jiangxi ,China )

Abstract :The CA FE method simulated 3D 2microstructure in solidification processes was analyzed.The CA FE method is the combination of cellular automaton (CA )model with finite element (FE )method which is a macro 2micro coupling model ,and this method can simulate the competitive growth of columnar grains and equiaxed grains ,the formation of columnar region ,relationship between grain boundary orientation and hot grads ,colum 2nar 2to 2equiaxed transition ,and the shape of equiaxed grains in non 2isothermal temperature field ,etc.The nuclea 2tion density is described by Gaussian distribution in the CA FE model.Calculation of kinetics of the dendrite tip growth is done according to the model of KGT.The crystallographic orientation <100>is selected preferentially ,and the competition of crystal growth is developed directly.The coupling of FE and CA is realized through the in 2terpolation between FE mesh and CA cells.Based on the CAFE method ,3D 2microstructure of 9SMn28free cutting steel was simulated in solidification processes ,and the simulation results are consistent with those of experiment.The composition of 9SMn28f ree cutting steel was optimized ;the optimum C ,P ,Mn ,Si and S contents are 0115%,0110%,112%,0108%and 0136%,respectively.The optimization results were also simulated and the solidifica 2tion structure is improved obviously.

K ey w ords :cellular autometion 2finite element model ;simulation ;microstructure

凝固过程的微观组织模拟是指在晶粒尺度上对

铸件凝固过程进行模拟,对铸件凝固过程的微观模拟和做少量实验即可预测铸件凝固组织和力学性能。微观组织模拟最初采用确定性模型,但由于该模型不能考虑晶粒生长过程中的一些随机现象,忽

略了枝晶生长的不连续性及晶体学的影响,它不能考虑始于铸型表面晶粒生长过程中的选择机制[1]。为改善这些局限性,20世纪80年代发展了概率模型,该模型主要采用概率方法来研究晶粒的形核与长大,包括形核位置的随机分布和晶粒晶向的随机