Modelling kinetics of phase transformation for the indirect hot stamping process to focus on car body parts with tailored properties
Modelling kinetics of phase transformation for the indirect hot stamping process to focus on car body parts with tailored properties
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DOI：
10.1016/j.jmatprotec.2015.01.003
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发表时间：
2016-02-01
影响因子：
6.3
通讯作者：
Merklein, Marion
中科院分区：
文献类型：
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作者：
Hippchen, Paul;Lipp, Arnulf;Merklein, Marion
为了设计间接热冲压工艺，需要基于有限元方法 (FEM) 来预测零件几何形状和机械性能。在间接热冲压工艺中，生产具有定制特性的车身零件时，会出现冷却路径，导致无扩散和扩散控制相变。面心立方体 (fcc) 相变到体心立方体 (bcc) 以及体心四方体 (bct) 马氏体形成引起的体积膨胀会产生相变诱发应变，这对于计算热冲压车身零件的整体应力非常重要。为了正确计算应变和应力状态，有必要对无扩散和扩散控制相变现象进行建模，同时考虑间接热冲压工艺的边界条件。对现有的材料模型进行了分析和扩展，以提高其在计算退火全过程中铁素体、珍珠体、贝氏体和马氏体含量和分布的预测精度。对于工业用途，新方法在 FE 代码 LS-DYNA 971（利弗莫尔软件技术公司，2006 年）中实施。 (C) 2015 年作者。由 Elsevier B.V. 出版
To design the indirect hot stamping process, a finite element method (FEM) based prediction of the part geometry and the mechanical properties is required. In case of indirect hot stamping processes, producing car body parts with tailored properties, cooling paths occur causing diffusionless and diffusion controlled phase transformations. The volume expansion caused by the phase transformation of face-centred cubic (fcc) into body-centred cubic (bcc) and the martensitic formation of body-centred tetragonal (bct) leads to transformation induced strains that are important for the calculation of overall stresses in hot stamped car body parts. To calculate the strain and stress state correctly, it is necessary to model the diffusionless and diffusion controlled phase transformation phenomena, taking into account the boundary conditions of indirect hot stamping processes. The existing material models are analysed and extended in order to improve their prediction accuracy in calculating the amount and distribution of ferrite, perlite, bainite and martensite during the whole process of annealing. For industrial use the new approaches are implemented in the FE-code LS-DYNA 971 (Livermore Software Technology Corporation, 2006). (C) 2015 The Authors. Published by Elsevier B.V.