Studies on the Hot Forming and Cold-Die Quenching of AA6082 Tailor Welded Blanks

An advanced forming process involving hot forming and cold-die quenching, also known as HFQ®, has been employed to form AA6082 tailor welded blanks (TWBs). The HFQ® process combines both forming and heat treatment in a single operation, whereby upon heating the TWB, it is stamped and held between cold tools to quench the component to room temperature. The material therefore undergoes temperature, strain rate or strain path changes during the operation. In this paper, a finite element model (FEM) was developed to investigate the formability and deformation characteristics of the TWBs under HFQ® conditions. Experimental results, i.e. strain distribution, were used to compare and validate the simulation results. A good agreement between the experiment and simulation has been achieved. The developed temperature, strain rate and strain path dependent forming limit prediction model has been implemented into FE simulation to capture the complicated failure features of the HFQ® formed TWBs. It is found from both experiment and simulation that the forming speed has important effects on the occurrence of failure position, where the failure mode for the 1.5-2 mm TWBs may change from localised circumferential necking to parallel weld necking.HFQ® is a registered trademark of Impression Technologies Ltd.

一种涉及热成型和冷模淬火的先进成型工艺（也称为HFQ®）已被用于成型AA6082拼焊板（TWBs）。HFQ®工艺在单一操作中结合了成型和热处理，即在加热拼焊板后，将其冲压并保持在冷模具之间，使部件淬火至室温。因此，材料在操作过程中会经历温度、应变速率或应变路径的变化。在本文中，开发了一个有限元模型（FEM）来研究拼焊板在HFQ®条件下的成型性和变形特性。实验结果（即应变分布）被用于比较和验证模拟结果。实验和模拟之间取得了良好的一致性。所开发的与温度、应变速率和应变路径相关的成型极限预测模型已被应用于有限元模拟中，以捕捉HFQ®成型拼焊板的复杂失效特征。从实验和模拟中都发现，成型速度对失效位置的出现有重要影响，其中1.5 - 2mm拼焊板的失效模式可能从局部圆周颈缩变为平行焊缝颈缩。HFQ®是英派科技有限公司的注册商标。