The heat transfer coefficient (HTC) is critical for hot stamping and in-die quenching. The air gap at interface is a dominant factor affecting the HTC, which is normally resulted from initial tooling clearance and thinning of deformed aluminum sheet. To precisely determine the HTCs under different air gaps, this research performed a comprehensive investigation on determining HTCs between an AA7075 blank and H13 tool steel. Hot stamping experiments were performed with different air gaps enabling HTC values were determined. Using the experimentally calibrated HTC, a finite-element model for hot stamping a door beam was established, which was successfully verified using the experimentation. The good predictions showed the reliability of the HTC values under different air gap conditions.

中文翻译：

---

具有空气间隙的热冲压AA7075板材的传热系数的实验表征

传热系数（HTC）对于热冲压和模内淬火至关重要。界面处的气隙是影响HTC的主要因素，这通常是由初始工具间隙和变形的铝板变薄导致的。为了精确确定不同气隙下的HTC，本研究对确定AA7075毛坯和H13工具钢之间的HTC进行了全面调查。使用不同的气隙进行热冲压实验，从而确定HTC值。使用经过实验校准的HTC，建立了对门梁进行热冲压的有限元模型，并通过实验成功验证了该模型。良好的预测表明，在不同的气隙条件下，HTC值的可靠性。