This study investigates the stress-strain distribution and failure prediction in equal-channel angular pressing dies for processing M1 copper plate using numerical simulations and experimental validation. Three die configurations were analyzed: a die without a ring, a die with a clamped ring and a die with shrink-fitting. The QForm industrial software was used for the simulations, while experimental pressing was conducted on a hydraulic machine to verify the pressing force and failure capacity. The results showed that a die without a ring was prone to failure under cold-pressing conditions. The die with a clamped ring exhibited a 27% reduction in tensile stress, whereas the shrink-fitted die achieved a 61.5% reduction compared to the die without a ring. The elastic strain also decreased significantly with the introduction of the die ring. The experimental M1 copper die withstood six passes without failure, with the workpiece showing signs of cracking during the sixth pass. These findings provide valuable information for designing ECAP dies for plate workpieces in industrial production, considering factors such as stress-strain distribution, fatigue life and practical implementation. The combination of theoretical calculations, numerical simulations and experimental validation offers a comprehensive approach to optimizing ECAP die design for enhanced performance and durability.