Experimental and numerical study of spring back of C-die forming in austenitic stainless steel 316 and carbon steel ST37 sheets with different thicknesses

At the end of the forming process, when the part is removed from the mandrel and the matrix and the part is loaded, a deformation occurs in the part, and this deformation after forming is called spring back. This research was carried out in order to experimentally determine the spring return of stainless steel 316 and carbon steel ST37 with different thicknesses in C-die forming and compare it with finite element simulation. The parts with three thicknesses of 1, 1.5, and 2 mm, forming and the geometrical dimensions of the spring back of the sheets have been verified. The results showed that the experimental spring back in the finite element simulation is consistent with the test, and also by reducing the thickness, spring back increases, which is affected by perfect elastic zone and surface plastic strain and membrane and bending stress.