Fatigue Life Prediction for an Extrusion Die Based on the Experimental Factors

According to the fact that the practical method for finding the working fatigue life is very expensive and takes a longer time with a huge amount of samples till the failure initiation of the die. So, the present research describes the main purpose of predicting the fatigue life of the die numerically based on the highest loading factors getting from the experimental work, indicating how many numbers of product samples can be produced during the whole life of this designed die depending on these loading or over. This fatigue life analysis and assessment were adopted by ANSYS Workbench 2019 R3 software depending on the loading factors (axial extrusion load and friction temperature difference) affecting the die strength and fatigue life during the experimental extrusion process. These factors were generated according to the variation of extrusion speed and changing product materials. The extrusion die was used to convert a cylindrical bar with (19) mm diameter into a square bar with (13 × 13) mm with an extrusion rate of 1.67. The results showed that the highest stress intensity factor reached about (251.4 MPa) at the critical converge-diverge section due to the die profile design, and the die is safe and has an infinite life reaching up to (10^9 cycles), using Lead or Aluminum products taking the maximum extrusion load of (90 kN) and temperature difference of (2 ℃) at 150 mm/min extrusion speed. While changing the product billet into harder materials, the die life decreased and might fail later.