Die Wear CAE Analysis And Lifetime Prediction Of Ultra High Strength Steel Stamping

The rapid development of automobile industry has made the energy problem increasingly serious, the inevitable choice of automobile industry development is to realize lightweight of automobile, reduce emissions and save energy. Ultra high strength steel with high strength and elongation that can satisfy the automotive requirements of lightweight and collision safety, has been widely used in automobile body structure components, security reinforcement components and other important components. But the high strength of ultra high strength steel leads to the working condition of stamping die is bad during the stamping process, when the load is bigger and die wear situation is more serious, which brings a series of problems for the design and application of automobile die. At present, most wear research mainly concentrates in the experiments, the results are influenced by a variety of external conditions, so it is difficult to provide fast method for the engineering design. Some numerical simulation of die wear in extrusion, forging and other forming process have been studied, but the research for super-high strength steel stamping die is less.Aiming at the phenomenon, this paper proposed an effective and fast method for predicting die wear and working life. Based on the dynamic display algorithm, the method adopted Archard wear theory and used Lagrange incremental method to simulate the stamping process of sheet metal. Much data including the stress of sheet metal and wear, relative sliding speed, contact pressure of die were obtained after stamping forming, the results showed that die wear was mainly concentrated in the die round corners.In order to study the influencing factors of die wear, this paper respectively changed the die hardness, stamping speed, die materials, die clearance and stamping stroke for numerical simulations, the influence law of various factors on the die wear was summarized by comparing and analyzing the biggest die wear. The results showed that the die wear had an inverse nonlinear relation with die hardness and die clearance within a certain range; die wear was positively correlated with stamping speed; the various materials had different wear resistance; and the relationship of die wear and stamping stroke were complex.Finally, considering the influence on subsequent stamping of previous stamping in practical production, wear accumulation method was used to predict the service life of die before die is repaired. And the actual die wear was measured by the white light scanning experiment, the error between simulation results and test data was small, which showed that the CAE analysis method is feasible, the method has an important practical value on determining reasonable stamping process and designing die structure.