Alternative Approach for the Intercritical Annealing of (Cr, Mo, V)-Alloyed TRIP-Assisted Steel before Austempering

TRIP-assisted C-Si-Mn steels are usually subjected to austempering with a preliminary intercritical annealing that is targeted at the multi-phase structure 40–60 vol.% of proeutectoid ferrite. The kinetics and mechanism phase-structural transformations can be impacted due additional alloying steel by strong carbide forming elements, thus necessitating an alternative approach for selection parameters. This issue analyzed in present work, which investigates effect temperature on “Structure/Properties” correlations 0.2 wt.% C-Si-Mn-Nb additionally alloyed 0.55 Cr, 0.20% Mo, 0.11 V. ranged from 770 °C 950 °C, was performed 350 20 min. It observed addition (Cr, V) complex significantly improved hardenability. However, (to gain 50 ferrite) resulted precipitation coarse cementite lamellas during bainite transformation, lowering amount retained austenite (RA) decreasing strength ductility steel. At higher temperatures, carbide-free formed, presented 2.5–3.5 times increase RA volume fraction 1.5 carbon content. optimal combination mechanical properties (UTS 1040 MPa, TEL 23%, V-notch impact toughness 95 J/cm2, PSE 23.9 GPa·%) referred close Ac3 point, resulting 5 ferrite 9 (the residue bainite). extended manifestation TRIP enhanced strain hardening rate strain-induced martensite transformation. elements activity served as basis analysis formation.