From this result, the optimum press pressure Po is around
310 MPa. The bending moment Mrs decreased with increase of the
press pressure P in the similar way to the warp height ıL which was
shown in Fig. 4.
metal, i.e. rsmax = 0 MPa, the press should not be given to the sheet
metal without the residual stress as it could cause the warp in the
opposite direction.
5