An investigation on the variation of surface areas in upsetting of cylindrical specimen

PurposeThe purpose of presented study is to investigate the development of the barreling obtaining the variation of the surface area during upsetting of cylindrical specimens for various metals and alloys.Design/methodology/approachVariations of the surface areas were first obtained analytically using mathematical equations for uniform and non‐uniform upsetting. Barreling contours were accepted as circular segments in the development of the equations. In the experimental part of the study, barreling radii and other related dimensions of upset specimens were measured and inserted into the developed equations in order to obtain the variations of total specimen surface areas.FindingsAs it is expected, barreling effects the variation of total surface areas of the specimen. It can be concluded that the total surface area first decreases at low upset ratios for all the test materials and then begins to increase as the upset ratios increases. Consequently, total surface areas for non‐uniform upsetting are always smaller that those of uniform upsetting.Research limitations/implicationsFive kinds of materials were used in the experimental part of the study. Specimens were also upset without lubrication. A relatively slow hydraulic press was used during the experiments with 5 mm/s ram speed.Practical implicationsAlthough the study has not direct implications for the practical purposes in forging area, results can be used as a very useful source of information for researchers in this field to plan their studies. Variation character of total surface area obtained in the study may give useful data in analyzing the deformation patterns in upsetting.Originality/valueThe effects of barreling on the material behavior in upsetting for non‐uniform conditions were analyzed with respect to variation of total specimen surface area. This point of view may be extended for different materials and friction conditions.