Study On The Influencing Factors In Stamping Forming Of Polyline Weld Tailor-Welded Blanks

As an important approach to the automobile light-weight, forming technology of tailor-welded blanks (TWBs) has been broadly applied in automobile industry. Polyline weld TWB is a kind of curved line TWBs with a bright application. However, there are two welds intersecting a certain angle on it. The deformation of the blank around the weld become very uneven when the material properties, thickness and others of the blanks at both sides of the weld are different. Then some problems like weld-line movement, degradation of formability occur in the stamping process of TWBs. Therefore, some related studies, on the main factors influencing the forming of the polyline weld TWB, could not only provide a theoretical basis for the control and improvement of the TWBs'formability, but also bring a wide application of these TWBs to the automobile industry.Square-box part is a typical non-axisymmetric species, and taking it as an object to study the stamping formability of polyline weld TWB has some representations. According to the forming theory of square-box part and the deformation characteristics of TWB under force, some main factors were analyzed, including blank holder force (BHF), thickness difference, the mechanical properties of blank and the weld location. And simulations to the forming process of the polyline weld TWB under those different conditions were carried by DYNAFORM. Then some correlation forming laws were gained from this. Besides, some related moulds were designed and experimental studies on the forming process of the polyline weld TWB were carried out based on the simulation.Experiment and simulation results were in agreement, and they showed that the formability of the blank around the weld turning point was not good. BHF, thickness difference, the mechanical properties of blank and the weld location had a great influence on the weld-line movement distance and the forming limit of the polyline weld TWB in its forming process. Therefore, reasonable design of the TWB and the rational choice of the forming process parameters could not only avoid the defects like cracking and wrinkling, but also control the weld-line movement distance and improve the stamping formability of the TWBs.