Comparative Evaluation of WCLV (1.2344), Uddeholm Unimax, and Uddeholm QRO 90 Supreme Tool Steels for Die Forging

This study presents a comparative evaluation of the wear performance of three hot-work tool steels-WCLV (1.2344), Uddeholm Unimax, and Uddeholm QRO 90 Supreme-for die forging applications. The materials were characterized in terms of hardness and bulk chemical composition using Vickers hardness testing and X-ray fluorescence spectroscopy. Tribological behavior was investigated using ball-on-disc tests, while industrial performance was assessed by analyzing forging punches after the production of 16,250 components. Surface degradation was quantified using optical profilometry and three-dimensional roughness parameters. Measured hardness values were 591 HV for WCLV, 622 HV for QRO 90 Supreme, and 639 HV for Uddeholm Unimax. The average friction coefficients were 0.88, 0.92, and 0.77, respectively. Unimax also exhibited the lowest volumetric wear, reaching 0.04683 mm³ (R19 mm) and 0.03384 mm³ (R22 mm), compared with 0.08646-0.13095 mm³ for WCLV and 0.09598-0.13635 mm³ for QRO 90 Supreme. This corresponds to approximately 45-70% lower wear relative to the other steels. Industrial trials confirmed improved surface stability of Unimax punches after service. The observed trends are consistent with differences in alloying content and the expected microstructural response associated with chromium and molybdenum additions. Overall, Uddeholm Unimax demonstrated the most favorable balance of hardness, friction behavior, and wear resistance.