Finite Element Simulation of the Tool Steel Stress Response As Used In a Hot Forging

作     者：Hjerstsén, David Sjöstrom, Johnny Bergström, Jens Näsström, Mats Ghosh, S. Castro, J. C. Lee, J. K 

作者机构：Department of Computer Aided Design Luleå University of Technology Luleå Sweden Department of Materials Engineering Karlstad University Sweden 

出 版 物：《AIP Conference Proceedings》 (美国物理学会会议录)

年 卷 期：2004年第712卷第1期

页      面：560-565页

学科分类：07[理学] 0702[理学-物理学] 

主　　题：FINITE element method FORGING MANUFACTURING processes MILLS & mill-work 

摘      要：Hot-work forging tools are subjected to severe and complex loading conditions (cyclic stress/strain conditions, varying strain rates, varying temperature, environmental damage), leading to short die life. There is also a temperature and time dependant material response to consider. Presently, hot-forging of a steel crankshaft is approached by a combined experimental and numerical simulation study of a hot-work tool steel. The forging conditions were investigated by thermal measurements and damage analysis. Laboratory testing by isothermal fatigue in the temperature range 200 – 600 °C was performed. An elasto-plastic kinematic and isotropic hardening model (according to Chaboche) was used to model the material behaviour where the material parameters were derived from the experimental part. Viscoplastic effects are not accounted for in the material model as they have minor influence on the stress-strain relation in the experimental setup. The model was implemented in a FEM program (***) using a semi-implicit time integration scheme according to Shih and Ortiz, and evaluated by modelling of the isothermal fatigue tests. The FE-results managed to describe the materials general behavior, the correlation between the experimental simulated values were however not satisfactory due to influence of factors in the parameter derivation. Important features of the material behaviour are the cyclic softening and its dependence of the temperature, and also the strain path history. The long-term goal is to fully analyze the hot-forging die in service by numerical simulation and to study the influence of manufacturing processes on die properties. © 2004 American Institute of Physics [ABSTRACT FROM AUTHOR]