In the study conducted for this contribution, sheet material 4 mm thick, non-heat treated (II), normalized (NH) and tempering heat treatment implemented (TH), were formed at a bending angle of 90°. As a result of the forming process, the effects of the R2, R3, R4, R5, and R6 mm punch tip radii on spring back and spring go values were investigated. The bending operations were carried out by waiting for the punch in the material bending zone for 30 sec and then lifting. The samples were extracted from the middle deformation zone of the II, NH and TH applied sheet material, to which the bending process was applied, following which their ferrite phase, pearlite and martensite structures were microstructurally analyzed. A Minitab analysis program was used to investigate the effect of the bending parameters on the sheet material’s spring-back and spring-go behavior. Moreover, the effects of bending parameters were investigated by creating numerical and mathematical models. Thus, it was determined that spring-go behavior occurred on the II and NH applied sheet material, while spring-back behavior occurred on the TH applied material.