白清领
,
李宏祥
,
向曙光
,
王正安
,
游江海
,
张济山
,
庄林忠
稀有金属材料与工程
采用某铝业公司提供的铸造工艺参数,基于温度场、应力场和流场三场的耦合系统研究了铸造工艺参数设置对熔铸过程的影响.结果显示,铸造速度对应力场影响非常大,而铸造温度、水流量对应力场的影响则不太明显.针对800 mm铸锭热裂问题,通过数值模拟对原工艺参数进行了优化.
关键词:
7050铝合金
,
热裂
,
应力场
,
参数优化
彭建
,
王永建
,
钟丽萍
,
孙勇
,
彭龙飞
材料热处理学报
对5052铝合金板材热轧过程进行了三维热力耦合模拟,综合考虑热轧过程中轧制速度、变形温度、道次压下量和摩擦系数等因素对热轧过程中轧件变形区内塑性变形和应力分布的影响,建立了多参数的热力耦合热轧模型.结果表明,在轧件变形区内,因加工硬化与动态软化的综合作用,其流变应力呈典型的动态再结晶特征.在变形区内轧件表面因金属流动剧烈,其等效塑性应变和应变速率远远大于轧件心部,塑性变形显著.轧制速度是轧件温度场分布最重要的影响因素之一,轧制速度越大,轧件的温升就越高;而温度是影响等效应力大小的主要因素,温度升高和应变速率降低都使得流变应力降低.
关键词:
5052铝合金
,
热轧
,
热力耦合
,
塑性变形
,
应力场
L. W. Zhang
,
J. Th.M.De Hosson
,
Y.L. Xia and F. G. Wang 1)The State Key Lab. for Materials Modification by Laser
,
Ion and Beams
,
Dalian University of Technology
,
Dalian 116023
,
China 2)Department of Applied Physics
,
University of Froningen
,
The Netherlands
金属学报(英文版)
In this paper,a thermal elastic-plastic 2-D finite element model of stress generation during laser transformation hardening process was developed. In this model, the mechanical properties of the material, Young's modules E, Poisson's ratio v, yield limit s, and thermal expansion coefficient α, are all change with temperature. The equivalent expansion method was used to deal with the problem with phase transformation. Based on this model, a program to calculate the residual stress field was developed using FORTRAN language. The residual stress fields in CO2 laser transformation hardened MoCu nodular iron were calculated. The calculated results showed that in the transformation hardened zone, the residual stress state is compress,whereas adjacent to this zone the residual stress state is tensile, and there is a tensile stress peak close to the transformation hardened zone. To verify this model, the residual stress fields were measured using X-ray diffraction method. The calculated results of residual stress fields are in good agreement with the experimental results.
关键词:
laser
,
null
,
null
,
null
,
null
J. F. Gu
,
J. S. Pan
,
M. J. Hu and F. F. Shen (School of Materials Science and Engineering
,
Shanghai Jiao Tong University
,
Shanghai 200030
,
China)
金属学报(英文版)
Complicated changns occur inside the steel parts during quenching process. The abruptly changed boundary conditions make the temperature field,micro - structure and stress field change dramatically in very short time, and these variables take a contact interactions in the whole process. In this paper, a three dimensional non - linear mathematical model for queeching process has been founded and the numerical simulation on temperature field,microstructre and stress field has been realized.In the FEM analysis, the incremental iteration method is used to deal with such complicated nonlinear as boundary nonlinear, physical property nonlinear,transformation nonlinear etc.The effect of stress on transformation kinetics has been considered in the calculation of microstructure. In the stress field anal- ysis,a thermo- elasto - plastic model has been founded, which considers such factors as transforma- tion strain,transformation plastic strain, themal strain and the effect of temperature and transforma- tion on mechanical propertier etc. The transient temperature field, microstructure distribution and stress field of the roller on any time can be displayed vividly,and the cooling curve and the changes of stress on any position can also be given.
关键词:
quenching
,
null
,
null
,
null
,
null
,
null
