Precise local deformation control for UHSS thin-walled component in roll forming

Aiming to the local area insufficient deformation of the UHSS thin-walled component leading to the scratched surface, the three-dimensional integrated finite element model of multi-pass roll forming was established with the professional design software COPRA. The interaction of the friction conditions between the strip and the rolls, the unexpected sliding velocity and material behavior are the main affecting factors to the insufficient local deformation of the surface of the UHSS thin-walled component. The insufficient deformation is mainly caused by the shear stress-strain, increases with the increase of material strength, and will be visible when the relative slide velocity exceeds the critical value 100 mm/s. According to the roll forming process, a precise control method of selecting the same local area velocity between the rolls and the strip, correcting the roll contours and improving the friction condition was proposed. The simulation results by applying proposed method shown that the peaks of shear stress and shear strain were reduced by 31.3 % and 73.3 % respectively compared with the initial simulation model, the stress concentration areas basically disappeared and the local deformation of profile surface is sufficient, and the high-precision quality requirements of the product are obtained by industrial experiment, which can provide a theoretical reference for actual production practice.