Thermal contact resistance estimation and metallurgical transformation identification during the hot stamping
Thermal contact resistance estimation and metallurgical transformation identification during the hot stamping
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DOI：
10.1016/j.applthermaleng.2013.07.041
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发表时间：
2013-11
影响因子：
6.4
通讯作者：
Alexandre Blaise;B. Bourouga;B. Abdulhay;C. Dessain
中科院分区：
文献类型：
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作者：
Alexandre Blaise;B. Bourouga;B. Abdulhay;C. Dessain
本文主要介绍热压印的热特性.提出了一种新的方法来估计工具和坯料之间的热接触电阻，冶金模型参数和潜热，描述了在热冲压过程中的奥氏体到马氏体的转变。测量是通过模具中的两个热电偶进行的，两个在冲头中，一个在坯料的一半厚度处。所有热电偶都根据热流方向对齐，将热问题减少到一维。通过求解两个热传导反问题（IHCP），利用测量得到的模具内部温度，估算了模具-坯料界面上的热流密度。使用这些估计的热通量作为边界条件的空白和空白中的测量温度，第三IHCP分辨率允许估计的源项的热方程，描述的冶金转变的放热性质。这种热释放也可以通过直接微积分来确定。这些技术所使用的假设的有效性进行了讨论。最后，热释放的演变可以与冶金转化动力学以及允许估计Koistinen-Marburger参数的转化潜热相关联。这些数据将用于执行精确的热冲压FE模拟。
This paper is devoted to the thermal aspects of hot stamping. An original way to estimate the thermal contact resistances between the tools and the blank, the metallurgical model parameters and the latent heat that describe the austenite to martensite transformation during a hot stamping process is presented. The measurements are made thanks to two thermocouples in the die, two in the punch and one the half-thickness of the blank. All thermocouples are aligned according to the heat flow direction, reducing the heat problem to one dimension. With the measured temperatures in the tools, the heat fluxes that cross the tools–blank interfaces are estimated solving two Inverse Heat Conduction Problems (IHCP). Using these estimated heat fluxes as boundary conditions in the blank and the measured temperature in the blank, a third IHCP resolution allows the estimation of a source term in the heat equation that describes the exothermic nature of the metallurgical transformation. This heat release can be also determined by direct calculus. The validity of the assumptions used by these techniques is discussed. Finally, the evolution of the heat release can be linked to the metallurgical transformation kinetic as well as the latent heat of the transformation allowing the estimation of Koistinen–Marburger parameters. These data will be used to perform accurate hot stamping FE simulations.