Springback characteristics in U-channel forming of tailor rolled blank

Huawei ZHANG 1), Lizhong LIU 1), Ping HU 1) and Xianghua LIU 2)( 1) School of Automotive Engineering, Faculty of Vehicle Engineering and Mechanics, State Key Labora- tory of Structural Analysis for Industrial Equipment, Dalian University of Technology, Dalian 116024, China 2) Research Institute of Science and Technology, Northeastern University, Shenyang 110819, China)

摘 要：Residual stress developed during the rolling process of tailor rolled blank （TRB） can affect the springback of finished parts considerably. Springback characteristics of unannealed and annealed TRBs were investigated by means of numerical simulation and experiments taking U-Channel as an example. TRBs were annealed by the annealing process （700 ℃, holding time 10 h）, then stamping and springback processes of unannealed and annealed TRBs were simulated, and corresponding experiments were also carried out. Effects of the transition zone length, the blank thickness, the friction coeffcient and the die clearance on the springback of TRB were analyzed. The results demonstrate that the springback of TRB annealed at 700 ℃ for 10 h reduces significantly. For unannealed and annealed U-Channels, the springback of TRB U-Channel is in direct proportion to the die clearance and is in inverse proportion to the transition zone length, the blank thickness and the friction coeffcient. Springbacks of the thinner monolithic （uniform thickness） blank, the thinner side of TRB, the thicker side of TRB and the thicker monolithic blank are sorted in descending order.

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