Investigation on the Increasing Material Hardness on Fineblanked Sprocket

Abstract

In cold working metal forming process, severe plastic deformation results in changes in the material properties. Earlier researches mainly investigated the rolling and equal channel angular extrusion (ECAE) processes. This study focuses on the fine-blanking process, specially the increasing material hardness on the fineblanked sprocket part. The microstructure around the cut surface is observed and the finite element analysis is done to clarify the mechanism of the increasing hardness as well. The microstructure revealed increasingly compressed and elongated grain structure of the contributed grain flow and orientation, as the blankholder and counterpunch forces increased. This resulted in the increased material hardness around the cut surface. Thus, these results theoretically clarified the mechanism of the increasing material hardness in the fine-blanking process regarding microstructural evolution, with the associated finite element analysis. Therefore, the special characteristic features in the fine-blanking process, result in the pronounced hardening around the fineblanked surface.

Shear cutting induced residual stresses in involute gears and resulting tooth root bending strength of a fineblanked gear

“…It has been shown by Thipprakmas et al [35] that a significant hardness increase by strain hardening is present in fineblanked parts. This hardness distribution can be controlled within a small range by the blank holder and counter punch force, for example.…”