It is proposed to study the state of deformation of the material subjected to cutting technological operations. The study is based on finite deformation theory, according to which an elementary sphere imagined in the material subjected to deformation is transformed into an elementary ellipsoid. It used the method of grids or networks division applied semi-finished which was cut by two types of punches made from improved, unused OSC 10 and used OSC 10 after 15.000 cuttings. Also are analyzed the metallographic structures of the samples that are in different stages of penetration of the active cutting tool in semi-finished material. It is observed the deformation, the appearance and the structure for the action of the both punches on the semi-finished.