The influence of Particle Hardness on Wear in Sheet Metal Forming

Abstract

Abstract. Particles exist in any tribo-system, whether it is closed to the environment or not. These particles originate from various sources, for example: contaminants such as dust or fibres from the environment; wear debris from abrasive/adhesive wear; and particles that are intentionally included in lubricant formulations. The particles affect the tribo-system in which they occur, but it is not always clear how. In this work, three types of chemically inert particles of similar size but different hardness are mixed with an otherwise pure oil and tested tribologically. Three tribological testing methods, pin-on-disc, four-ball, and bending-under-tension, are used to investigate the effect of the particles on friction and wear under sheet metal forming conditions. The hardness of the particles had a large effect on wear development, but little to no effect on the coefficient of friction found by pin-on-disc testing. Including particles of any hardness helped the oil in which they were included resist variation in load, leading to less wear for higher loads compared to the pure oil.