Avaliação da estampabilidade de aços avançados de alta resistência para componentes de segurança veicular

Abstract

This study evaluated the formability of five advanced high-strength steels, designated as DP780, TRIP780, and TRIP1000 — intended for vehicle safety applications. To this end, microstructural characterisations were carried out through metallography, phase volume fraction analysis, crystallographic texture assessment, and phase morphology examination. Subsequently, mechanical and formability tests were conducted, organised into three lines of investigation: i) evaluation of mechanical properties using tensile testing, microhardness, mini-Charpy impact, bending, and Small Punch Test, aiming to assess behaviour in different rolling directions; ii) characterisation of formability based on Erichsen stretch, forming limit curve (FLC), conical hole expansion, and limiting drawing ratio (LDR) tests; iii) analysis of the correlation between microstructural parameters and performance in formability tests. The results indicated that: i) DP780 M, DP780 S, and TRIP780 steels exhibited the best combination of mechanical properties and formability; ii) although TRIP1000 showed high mechanical strength, it demonstrated lower energy absorption capacity and poorer formability, due to its microstructure and lower strain hardening exponent; iii) factors such as microstructural homogeneity, microhardness distribution, and the presence of retained austenite were important for stamping performance. These findings contribute to a better understanding of how microstructure influences the formability of advanced high-strength steels.