Експериментальне та чисельне дослідження комбінованих процесів осаджування та протягування при куванні гаків

The paper presents the results of an experimental and numerical investigation of the combined upsetting and drawing out processes of billets during the forging of heavy-duty hooks. The aim of the study is to analyse the distribution of plastic deformation in the billet cross-section and to verify the reliability of the numerical simulation by comparing the results of physical and computer modelling. Experimental investigations were carried out using the physical modelling method with C1 grade lead specimens, which were used as a model material for Steel 20. The coordinate grid method was applied to analyse the strain state. The cross-section was taken through the central part of the specimen, and the coordinate grid was applied to one half of the cross-section. The investigation was performed on cylindrical specimens with height-to-diameter ratios of h/D = 1 and h/D = 2. Upsetting was carried out to a deformation degree of 50%. Subsequently, drawing out was performed with deformation degrees of 10% and 20%, using the ring and longitudinal drawing schemes. Numerical simulation of the upsetting and drawing out processes was carried out using the QForm UK software package. A comparison of the deformed coordinate grid shape, logarithmic strains, and convergence coefficients obtained from the experimental and numerical investigations was performed. It was established that the highest strain values were observed in the central part of the specimen cross-section, whereas the strain intensity decreased towards the outer regions. The analysis of the convergence coefficients showed sufficient agreement between the results of the physical and numerical modelling. For most coordinate grid cells, the convergence coefficients were within the range of 0.8–1.2. The obtained results confirm the adequacy of the numerical model and the possibility of using the QForm UK software package to analyse the deformation distribution during the combined upsetting and drawing out processes. The results of the study may be used in the development of technological processes for forging heavy-duty hooks.