The formability of high strength steel plate applied TRB for stamping

Recently, research on lightweight automobiles is increasing continuously to respond to the high safety standards and environmental regulations. The application of high strength steel is one of the effective methods for developing lightweight car bodies. A TWB (Tailor Welded Blank) is major method that allows partial high strength with light weighting using a multi-thickness and multi-material welded blank. On the other hand, additional welding process is required to prepare the blank and quality control for the welding process also required. To secure this point, the TRB (Tailor Rolled Blank) method was suggested. In the TRB method, the thickness of sheet is controlled by the rolling presses and the production efficiency is much higher than welding in TWB methods. In this study, the formability of high strength TRB steel plate was analyzed to examine the rolling effect of the blank. The formability of the specimen was tested using 0.8 and 1 mm thick steel sheets for the TRB plate. The strain was analyzed by the digital image sensing of grid markings on the specimen and the forming limit diagram was calculated. An Erichsen test for the 0.8 and 1 mm thick TRB specimens was carried out and the formability was investigated by comparing with FE analysis.