Tribological performance of Orvar 2M tool steel coated with ALWIN XC for improved forging tool durability

Abstract This study presents a comprehensive evaluation of the tribological performance of hot-work tool steel Orvar 2M in its uncoated state and after surface modification with a hard physical vapor deposition (PVD) AlWIN XC coating, intended for hot forging applications. The research followed a sequential experimental approach, combining preliminary laboratory tests, advanced high-temperature tribological tests, and industrial verification. Preliminary dry-abrasive wear tests at room temperature were performed for both uncoated and coated variants. These tests provided an initial comparative assessment of abrasive wear resistance and allowed identification of dominant surface degradation mechanisms. The uncoated steel exhibited localized abrasive wear, including microcracks and scratches, while the AlWIN XC coating significantly reduced material loss and stabilized the wear process. For a more representative analysis, ball-on-disc tests were conducted at 200°C, corresponding to the operational temperature of forging tools. The AlWIN XC coating demonstrated a stable coefficient of friction and low wear rate. Scanning electron microscopy observations and energy dispersive X-ray spectroscopy analyses enabled correlation of microstructural and chemical changes with the main degradation mechanisms. Industrial-scale forging trials confirmed that coated tools achieved more than a twofold increase in lifespan compared to uncoated steel. The results demonstrate the reliability and relevance of the applied tribological testing methodology as a predictive tool for tool durability. These findings also support the further development and optimization of PVD-coated forging tools for enhanced service life under industrial conditions.