Regularities of Plasticity Reserve Restoration and Method of Its Calculation for Deformation by Intermediate Heat Treatment

Cold plastic deformation of tool steel P6M5 for different ways of deformation is investigated. The regularities of recovery of the used plasticity resource during annealing for the simple and complex ways of deformation of P6M5 steel are established. As shown, the history of deformation does not have a significant effect on the patterns of restoration of the plasticity reserve by intermediate heat treatment. A new method of calculating the ultimate degree of deformation during deformation for several transitions with intermediate heat treatments (annealing) is proposed that allows taking into account the influence of the deformation history, which preceded each transition, and the restoration of the plasticity resource by intermediate heat treatment that more fully reflects the essence of the processes taking place during cold deformation with intermediate annealing. This technique is based on the analysis of the results of experimental studies of cold plastic deformation of samples in the process of their deposition, stretching, twisting, and stretching with simultaneous twisting in two stages with intermediate annealing, which was carried out at a temperature of 760 degrees C and held for 1 hour with subsequent cooling with a furnace. Two methods of calculating the ultimate deformation of the workpiece material after annealing are proposed. The first one involves the construction of a new plasticity diagram, which takes into account the restoration of the plasticity reserve by intermediate annealing due to the geometrical construction of a new plasticity diagram based on the obtained experimental results for different deformation paths. The second technique involves the use of the dependence of the restoration of the used plasticity resource of the deformed material by annealing on the degree of deformation before annealing, which allows to calculate a new plasticity diagram that takes into account the restoration of the reserve of plasticity by heat treatment and allows to predict the possibility of deformation of the workpiece material after annealing without destroying it.