In hot forging process, tool life is an important factor which influences the economy of production. Wear mechanisms in these processes are dependent on each other, so modeling of them is a difficult problem. The present research is focused on development of a hybrid tool wear model for hot forging processes and evaluation of adding adhesive mechanism component to this model. Although adhesive wear is dominant in cases, in which sliding distances are large, there is a group of hot forging processes, in which adhesion is an important factor in specific tool parts. In the paper, a proposed hybrid tool wear model has been described and various adhesive wear models have been reviewed. The feasible model has been chosen, adapted and implemented. It has been shown that adding adhesive wear model increases predictive capabilities of the global hybrid tool wear model as far as characteristic hot forging processes is considered.
The paper presents a description of the phenomena occurring on the surface of the forging dies. A detailed analysis was made of 24 pre-forging dies due to the most intensive wear in this operation. To compare the results, new tools were also analysed. The research described in the study showed that the most dangerous factor for the hot forging process analysed is thermal-mechanical fatigue, which causes small cracks, which in turn quickly leads to the formation of a crack network on the entire contact surface of the tool with forged material. The second phenomenon is the tempering of the surface of the material for a long-term temperature effect. The presence of hard iron oxides in the form of scale from forging material is the accompanying phenomenon that intensifies the processes of tool wear. The paper presents the results of the analysis of the presence of residual magnetic field for forging tools and the results of laboratory tests of wear processes of tool steels for hot work in the presence of a magnetic field and in the presence of scale.