Abstract:
Over the past decade extensive development of advanced high strength steel
(AHSS) was driven by the demand from the automotive industry for stronger
materials that can enable lightweighting to meet increasing fuel efficiency requirements.
However, achievement of higher strength in many AHSS grades
comes with reductions in ductility, leading to geometric constraints on formability
and limiting their application. In this paper, a 3rd Generation AHSS
with a compelling property combination of high tensile strength of ~1200
MPa and total elongation > 40% was used for laboratory and stamping studies.
Various auto related laboratory tests were done including tensile testing,
180 degree bending, bulge testing, and cup drawing to estimate the steel’s
formability under different applied conditions. Additionally, since laboratory
testing provides only an estimation of the potential stamping response, the 3rd
Generation AHSS sheet was stamped into B-pillars under industrial stamping
conditions. Non-destructive and destructive analysis of the resulting stampings
were done to evaluate the microstructural and property changes occurring
during stamping. Significant strengthening of material in the stamped
part is attributed to the structural changes through the complex Nanophase
Refinement and Strengthening mechanism.
