Thickness Thinning and Transition Zone Movement of Tailor Rolled Blank under Different Blank Holder Force Modes

Abstract Tailor Rolled Blank(TRB) demonstrates great potential in the field of automotive lightweight, and thus the research on the formability of TRB is of high practical value. In this paper, the formability of Tailor Rolled Blank under different blank holder force(BHF) modes was studied through numerical simulations and stamping experiments by taking square box as the research object. The effects of BHF value and BHF type on the formability of TRB were analyzed, and the thickness thinning and the thickness transition zone(TTZ) movement for TRB part under different BHF modes were discussed. The findings indicate that the blank hold force plays an important role in the forming process of TRB. The segmented blank holder and the stepped mould gap adjustment plate can provide different blank hold forces and a uniform blank holding gap for the thinner side and the thicker side. Constant BHF and higher BHF value on the thinner side than that on the thicker side(4 tons on the thinner side and 2 tons on the thicker side) independent of time are advantageous to improving the formability of TRB.