Fatigue Failure Prediction Model and Verification of Hot Extrusion Die

Abstract

Fatigue fracture is one of the most common failure modes of hot extrusion dies. The fatigue properties of materials are closely related to service conditions and heat treatment processes. In this paper, the service conditions of typical hot extrusion punches were selected as the start point, loading history of the dangerous part of the die was obtained by finite element numerical simulation. The load spectrum modified and normalized through Neuber algorithm was used as the loading curve of fatigue analysis. The tensile properties of the die materials at service temperature were obtained by experiments. Based on the Manson-Coffin model, the strain-life curve of the material was obtained through the theoretical deduction. The fatigue failure prediction model was established based on strain damage. Aiming at specific working conditions of aluminum alloy extrusion parts, the fatigue life prediction and model validation of the die were carried out. The heat treatment of die was: spheroidizing annealing + 1020 ℃ oil quenching + 580 ℃× 2 h two tempering treatment. The results show that the die life predicted by the model is 1318 times, and the actual die life is 1120 times, the failure position and service life of the die are in good agreement with the predicted results. A new way was provided for optimizing the matching of heat treatment process and service condition of the die, and has guiding significance for actual production.