Influence of Plastic Deformation on Martensitic Transformation During Hot Stamping of Complex Structure Auto Parts
Influence of Plastic Deformation on Martensitic Transformation During Hot Stamping of Complex Structure Auto Parts
复制标题
复杂结构汽车零部件热冲压塑性变形对马氏体相变的影响
DOI：
10.1007/s11665-017-2579-9
复制
发表时间：
2017-04-01
影响因子：
2.3
通讯作者：
Lu, Jue
中科院分区：
文献类型：
--
作者：
Shen, Yuhan;Song, Yanli;Lu, Jue
采用热冲压工艺制造的超高强度钢汽车零部件因其轻量化和安全性的提高而得到广泛应用。在热冲压过程中，热成形和淬火在一个步骤中进行，其中塑性变形和相变同时发生并相互影响。其中，形变对马氏体相变的影响尤为重要。研究了复杂结构汽车零件热冲压成形过程中塑性变形对马氏体相变的影响。为此，采用热冲压工艺制造了B1500 HS钢B柱加强板，并基于热-力-冶金耦合模型，利用有限元软件对冲压过程进行了模拟。考虑不同的变形程度，对热冲压B柱加强板4个典型位置的组织和力学性能进行了检测。结果表明，马氏体含量和显微硬度随变形量的增加而增加。造成这一现象的原因有两个：（1）机械驱动力的增加;（2）在晶体缺陷处马氏体形核的可能性增加。X射线衍射分析表明，碳在残余奥氏体中富集，这是低碳马氏体形成过程中碳扩散的结果。此外，碳含量随着变形量的增加而降低，因为奥氏体的变形抑制了碳的扩散。
The ultra-high strength steel auto parts manufactured by hot stamping are widely applied for weight reduction and safety improvement. During the hot stamping process, hot forming and quenching are performed in one step wherein plastic deformation and phase transformation simultaneously take place and affect each other. Thereinto, the influence of deformation on martensitic transformation is of great importance. In the present paper, the influence of plastic deformation on martensitic transformation during hot stamping of complex structure auto parts was investigated. For this purpose, a B-pillar reinforced panel in B1500HS steel was manufactured by hot stamping, and the process was simulated by finite element software based on a thermo-mechanical-metallurgical coupled model. Considering various deformation degrees, the microstructures and mechanical properties at four typical locations of the hot stamped B-pillar reinforced panel were detected. The results show that the martensitic content and the microhardness increase with the increase in the deformation amount. There are two reasons causing this phenomenon: (1) the increase in mechanical driving force and (2) the increased probability of the martensitic nucleation at crystal defects. The x-ray diffraction analysis indicates the carbon enrichment in retained austenite which results from the carbon diffusion during the low-carbon martensite formation. Furthermore, the carbon content decreases with the increase in the deformation amount, because the deformation of austenite suppresses the carbon diffusion.