Friction in metal forming processes: a comprehensive review of experimental methods, influencing factors, and surface engineering approaches

Friction is a critical factor in metal forming processes, influencing material flow, surface quality, tool life, and overall production efficiency. This comprehensive review explores the experimental methods employed to evaluate friction behavior in metal forming, including pin-on-disk tests, ring compression tests, stretch forming tests, and tribometers. The integration of advanced measurement technologies such as infrared thermography, digital image correlation, and high-speed imaging has significantly improved the accuracy of friction assessments. Furthermore, the review highlights the key parameters affecting friction, including lubrication conditions, material pairings, surface roughness, and process temperature. Surface engineering strategies, such as coatings and texturing, are also discussed as effective approaches to control friction. The insights provided aim to support researchers and practitioners in selecting suitable evaluation techniques and in developing optimized surface treatments for enhanced metal forming performance.