Evaluation of ductile fracture model in bulk forming

Abstract

The purpose of this study is to evaluate the parameters of material plasticity and fracture models at room temperature and at rates up to 1 mm/min for steels which are ordinarily used for forging, for instance the 38MnVS6 steel. The behaviour of materials during forming was evaluated and described using MARC/MENTAT and DEFORM software tools. Several fracture models were examined from the perspective of the planned research tasks which involve testing at forging temperatures up to 1,100°C. The fracture models considered were those which are implemented as standard tools for example: Cockcroft and Latham, Oyane and Rice and Tracey. Standard tensile tests, torsion tests and compressive tests were carried out. Based on the tensile test data, an FEM analysis of the stress-strain curve was conducted. The ductile fracture models were then calibrated using multiple stress-strain conditions, including triaxial stress states and various lode angles.