Surface Smoothing Mechanism by Replication in Ironing Process

Abstract

The purpose of this paper is to clarify the surface smoothing process under contact states with a small relative slide between the tool and workpiece. An internal ironing apparatus was developed to observe the surface during the processing. Observation revealed that the surface smoothing process is largely developed during a very short contact length from the entrance of the contact zone where the bulk material is in the elastic state and can be markedly promoted by the plastic deformation in the surface layer. It was also confirmed that the ironed surface roughness decreases by increasing the ironing reduction in thickness and reaches the surface roughness of container Ra = 0.01 μm under dry condition and 30 percent in the reduction when initial surface roughness Ra is about 0.07 μm. The surface smoothing process could be understood by the slip-line field theory.