Investigation of springback of two-layer metallic sheet produced by explosive welding in U-die bending process

In the present study, the two-layer sheet made of commercially pure copper (CP-Cu) and 304 stainless steel (SS-304) was fabricated by using explosive welding process and then was formed in U-shape bending process. In the study, the load was analyzed and effect of parameters such as punch tip radius, sheet thickness, friction coefficient, and mechanical properties on spring back of the two-layer sheet was investigated using experiments and finite element simulation. The results of this research show that, by increasing the strength and modulus of elasticity of material, thickness of sheet, the friction coefficient between die wall and sheet and reducing the punch tip radius, the spring back amount of sheet decreases. Moreover, the effect of mechanical properties of steel and increasing its thickness on the spring back reduction is more than the copper in two-layer metallic sheet.