FEM Modeling of the Distortion of Blank/Case Hardened SAE 5120 Gear Blanks Due to Chemical Banding

Abstract

In this study, a FEM process-chain simulation model is presented for the prediction of distortion of blank and case-hardened SAE 5120 (EN 20MnCr5) steel gear blanks. For this purpose, the evolution of the banded microstructure stemming from the continuous casting process was traced by computer simulations of subsequent shape rolling, forging and machining steps. The calculated flow-net was imported into the in-house heat treatment simulation module empowered with the recently developed “Anisotropic Transformation Strain (ATS)” model which enables the inclusion of the effect of banded microstructure on distortion. Then, both blank and case-hardening processes were simulated and verified experimentally. The results indicate good predictions of the dishing directions and dishing-free cutting strategy in both cases, whereas; the dishing magnitude is predicted well in blank-hardening simulations while the quality of the prediction is reasonable in case-hardening.

Keywords

Gear, Blank-Hardening, Case-hardening, Distortion, Process-chain simulation, Anisotropic Transformation Strain, SAE 5120