Effect of Cold-Forming on Mechanical Properties of AHSS Steel

Advanced high-strength steels (AHSS) can offer an excellent combination of high strength and light weight for applications including cold forming. These steels may be used in press braking and profile and section manufacturing. The aim of this work is to study the mechanical properties and microstructure of steel used in the manufacturing of roll-formed profiles with decreased radii. In this study, ferritic feedstock steel with 450 N/mm² yield strength, coiled at room temperature, and the sections with wall thicknesses of 7.1 mm and 12.5 mm are studied with middle line radii of 7.5 mm and 13 mm, respectively. Mechanical properties and impact toughness, especially considering the corners of cold-formed profiles, without and with aging (250 °C for 1 h), are studied. Cold deformation on corners is influenced by thickness and tensile strength in aged conditions. Impact energies are at a high level at-40 °C and-60 °C, and aging does influence the toughness but not on the hardness.