Experimental and numerical investigation of cold forging tool degradation due to plastic deformation

Cold forging tools are subjected to repeated high contact pressures that may cause progressive plastic strain accumulation, residual stress development, and premature failure. This study presents an experimental–numerical methodology to evaluate plastic deformation and lifetime prediction in an AISI H13 cold forging tool. A cylindrical H13 tool was tested in a hydraulic press under repeated loading against a W350 steel die. The tool response was measured using a strain-gauge rosette and a load cell, allowing the effective strain, stress state, residual strain, and damage evolution to be estimated during the press cycles. The experimental data was used to adjust an analytical Johnson-Cook based plastic strain model and to validate a finite element model developed in QForm software. The results showed that tool fracture occurred when the accumulated permanent effective strain reached 6,674 µstrain. The adjusted Johnson-Cook model predicted failure close to the experimental fracture strain and before the phase of imminent material failure, whereas the FEM-based damage model predicted failure after a higher number of cycles.