PAIR Distinguished Lecture Series: How to get high quality experimental data for hot stamping?

To meet the global requirement of energy saving and CO₂ emission reduction for transportation vehicles, great efforts have been made over the years to reduce the weight of vehicles by replacing the current heavy metal structures with light alloys, such as aluminium and magnesium alloys. However, the common problem for light alloys is that they are brittle and difficult to form complex-shaped structural panel components. Thus hot stamping techniques have been developed in recent years to enable high strength alloys to be stamped into complex-shaped components in one operation, such as “HFQ^®-Technology” for high strength aluminium alloys.

In this presentation, thermal-mechanical testing requirements to meet real production conditions are outlined first. The temperature profile control and strain field measurements within the gauge length of specimens, together with the spatio-temporal method for determining necking and fracture strains of sheet metals, will also be presented. Special attention will be paid to the development of biaxial test facilities for generating forming limit diagrams (FLD) and fracture forming limit diagrams (FFLD). At the end of the presentation, the creation of unified viscoplastic constitutive equations for hot stamping process modelling will be presented.