Thermo-Mechanical and Damage Evolution at the Sidewall–Bottom-Corner Transition in 22MnB5 Steel during Hot Stamping

Yuanxiang Wang, Weilun Deng and Hongxing Zheng

DOI: https://doi.org/10.64486/m.66.2.10
Online publication date: September 24, 2026

Abstract: Hot stamping of 22MnB5 boron steel enables high-strength automotive components, but local deformation and damage may develop in geometrically constrained regions such as the sidewall–bottom-corner transition. A thermo-mechanically coupled DEFORM-3D finite element model was developed to examine local temperature, effective stress, effective plastic strain, and Damage under variations in die-entry temperature, punch speed, and friction coefficient. The deformation-sensitive region remained spatially stable, though its response magnitude varied with process conditions. Increasing die-entry temperature (750–850) °C reduced effective stress through thermal softening, with little change in final effective plastic strain and Damage. Increasing punch speed (50–150) mm×s^-1 improved temperature retention and reduced effective stress, but increased effective plastic strain and Damage; increasing friction coefficient (0.3–0.7) substantially increased effective plastic strain and Damage with only limited effects on temperature and stress. Final Damage correlated strongly with final effective plastic strain (R² = 0.99, partly reflecting the cumulative NCL formulation) but showed a weaker correlation with final effective stress (R² = 0.62), indicating that instantaneous stress and accumulated Damage may exhibit different process-dependent trends and should therefore be considered jointly when assessing local deformation and damage accumulation.

Keywords: 22MnB5 boron steel; hot-stamp bending; finite element simulation; ductile damage; thermo-mechanical response

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