Modelling Kinetics of Phase Transformation for the Indirect Hot Stamping Process

Abstract:

To configure the indirect hot stamping process, a finite-element-based prediction of the parts geometry and mechanical properties is required. In case of indirect hot stamping, inhomogeneous cooling schedules cause different phase transformation points and products. The volume expansion caused by phase transformation of fcc into bcc leads to transformation induced stresses that are important for the calculation of overall stresses in press hardened components. To calculate theses stresses correctly, it is necessary to study the kinetics of phase transformation in consideration of the cooling path of an indirect hot stamping process. Dilatometer tests are employed to obtain the kinetics of phase transformation is determined in dilatometer tests. These results are used to identify the parameters for the phase transformation models implemented in the material model *MAT_244 [ that is implemented in the finite-element-code LS-DYNA [. In this context the material model parameters are identified by using evolutionary optimization strategies. Based on the identified parameters the predictive quality of the implemented phase transformation models will be studied in order to improve their prediction accuracy for the indirect hot stamping process.

• Periodical: Key Engineering Materials (Volume 549)
• Pages: 108-116
• DOI: https://doi.org/10.4028/www.scientific.net/KEM.549.108
• Online since: April 2013
• Authors: Paul Hippchen, Marion Merklein, Arnulf Lipp, Michael Fleischer, Hannes Grass, Craighero Philipp
• Keywords: Hot Stamping, Kinetics of Phase Transformation, LS-DYNA, Simulation

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