Die-Forging Process Design and Forming-Load Optimization for a G55 Wheel-Hub-Bearing Inner Ring

J. H. Huang, B. Zhang, Z. L. Liao, H. B. Fu, and H. P. Ma

DOI: https://doi.org/10.64486/m.66.2.6
Online publication date: August 27, 2026

Abstract: This study characterized the hot-deformation behavior of G55 steel used in wheel-hub-bearing inner rings and obtained true stress-strain curves from compression tests. A three-stage die-forging route, comprising upsetting, pre-forging, and final forging, was simulated in DEFORM-3D. An L₉(3³) orthogonal design with a smaller-the-better signal-to-noise (S/N) analysis was used to reduce the maximum forming load. The influence of the investigated factors decreased in the order initial billet temperature, shear-friction factor, and upper-die velocity. The lowest simulated load was 1.29 × 10⁷ N at 1200 °C, a friction factor of 0.3, and an upper-die velocity of 100 mm·s⁻¹. Trial forgings produced under these conditions were fully filled and showed no visible surface defects. The optimized process therefore provides a feasible process window for manufacturing the investigated inner ring.

Keywords: G55 steel; wheel-hub-bearing inner ring; die forging; finite-element simulation; orthogonal design; forming load

This article is published online first and will appear in Metalurgija, Vol. 66, Issue 2 (2027).