Selecting a Cutting Method for Workpieces Before Stamping Using Synergetic Fracture Criteria and a Deformability Limit Determination Technique for Separating Processes

To choose a rational method for cutting rolled stocks into workpieces made of materials with different mechanical properties, an engineer must have a set of tools that allow them to make such a choice. The results of the conducted research confirm the correctness of the conclusions that synergetic fracture criteria, such as the “crack growth criterion” and “brittleness criterion,” are the basic informative features. When any of the remaining complex criteria, such as the “crack initiation criterion” or “scale criterion” are added to them, they form the most informative sets of minimal power, ensuring with a given reliability the classification of materials according to their sensitivity to separation. The boundaries of zones have been established to classify materials that are in a “plastic state,” “elastoplastic state,” and “brittle state.” Recommendations have been developed for selecting a method for cutting rolled stocks into workpieces based on the values of the “crack growth criterion” and “brittleness criterion.” The results of the conducted research are well-aligned with experimental data obtained using the methodology for determining the ultimate deformability of rolled stocks applied to separation processes. The ultimate plasticity value is a suitable indicator for ranking metals according to their ability to be separated. The procedure for determining the ultimate plasticity value fully preserves the standardization of the test. Considering the mass production of cutting rolled stocks into workpieces, it is possible to expect an accelerated accumulation of information on the value of the ultimate plasticity for metals with different chemical and structural states, leading to the formation of a corresponding database.