1st Paragraph: Advanced high strength steels (AHSS) are increasingly being used in automobile industry to enhance vehicle crashworthiness, improve fuel economy and to reduce CO2 emissions. However, AHSS pose great challenge to the sheet metal forming processes in vehicle components manufacturing. In stamping process, the use of AHSS leads to the occurrence of “shear fracture” when sheet metal is drawn over a tight die radius and an increased level of die wear and springback. In roll forming, the edges of the strip are subjected to the longitudinal strains due to travelling a longer distance than the centerline. Furthermore, the material undergoes tension-compression cycling deformation especially when the strip passes through a roll stand. The redundant deformation is responsible for many major defects, such as camber, bow, twist and excessive springback.
Authors: Dayong Li, Shichao Ding, Lei Shi, Yaguang Li , Yong Sun, and R.H. Wagoner
Keywords: Advanced High Strength Steels (AHSS), Chain-Die Forming, Bauschinger Effect, U-Channel, Springback, Roll Forming