On the mechanism of two-body abrasive wear in turning “the spin-split theory”

Abstract

This approach regarding metal cutting in steel reveals the likely mechanisms behind a two-body abrasive wear. The theory is based on the assumption that ceramic hard inclusions in the secondary and tertiary cutting zones cannot to any significant extent be deformed plastically. The inclusions, in most cases roundish bullet-type particles, are forced to rotate or break due to the large shear stresses in the cutting zones. A bullet-type particle cannot efficiently cut or wear on the cutting tool rake and tool flank, but when the particle is torn apart, efficient sharp edges are created. Those edges are then, due to the elongation and contraction of the matrix material, pressed out towards the cutting tool, where they, while still rotating, cut until their cutting geometry become less favourable and at that point break into small fragments, which together with the matrix material are welded on the tool clearance and the tool rake faces. Those deposits with particle remnants and chips from the cutting tool contain 30–40% of ceramic material. The rest is matrix material from the workpiece. The understanding of this mechanism opens new ways to improve cutting materials, both coating and substrate, and the workpiece materials.