The dissertation is devoted to the determination of the basic regularities of metal forming when using a thin deforming tool, as well as to determine the deformation conditions of the maximum approximation of the shape and size of forging to the finished product and to create an advanced technology for the production of forgings of parts the type of "crankshaft"
On the basis of a literary review of the current state of developments in the field of manufacturing forgings of crankshafts, it has been found that forgings impose requirements for quality, which include the accuracy of geometry and the required level of mechanical properties. Closed-die forging and upsetting-bending method (TR-method) are used for serial production and have limitations on forging masses. The method of free forging is used mostly in single production and allows obtaining large-sized forgings. This achieved at the expense of significant metal costs. When applying a more "thin" deforming tool, it is possible to forge a crank pin, which will save metal due to the approaching form of forging to the finished part.
An improved method for estimating strain unevenness is also used in the work. This method is developed in co-authorship, and further development of the method is given in this paper. The essence of the improvement lies in a different method of data processing, namely, taking into account the difference between the mean values of the unevenness factor and the values of this parameter at certain points of the cross-section of forging. On the basis of the technology analysis, an experiment plan, consisting of nine experiments, was developed. As factors of influence, two parameters are chosen, namely the thickness of the deforming tool and the depth of its indentation. The form of the samples obtained after deformation has been analyzed, and the dependences of changes in geometric parameters in the zone of the formation of the crank pin from studied forging process parameters has been considered. The dependence of the change in the value of the effective diameter of the knee on the given forging parameters in the places of formation of the crank pin of the crankshaft was obtained. This allows assigning, with a certain thickness of the deforming tool, the level of compression to form the required diameter of the crank pin and the shaft cheek at the location of the knee. According to the experiment plan, a computer model, in program “QForm”, was constructed and a calculation was made. The estimation of the discrepancy of data between experiment and modeling showed that the error is not more than 10%. Were developed a scheme of cantings, that allows obtaining a crank pin with a round cross-section.
On the basis of the conducted researches results, the advanced technology of large crankshafts forgings production was developed. On the basis of the received regularities of metal shaping, recommendations on the application of a "thin" deforming tool were developed, and, using an improved method for determining the unevenness of deformation for a certain length of a crank pin, the number of coggings, rotation degrees and levels of deformation was determined. This allows to choose the variant of deformation (forging scheme) with minimal deformations unevenness of metal at the place of large crankshafts crank pin formation.
