Microstructure Evolution and Strengthening Mechanism of 30MnB5 and 40Mn2CrNbV Hot‐Stamped Steel

The present investigation employs conventional hot‐stamping methodology incorporating die quenching followed by 170 °C tempering to fabricate ultrahigh strength 40Mn2CrNbV hot‐stamped steel. The alloy demonstrates exceptional mechanical characteristics, achieving an ultimate tensile strength of 2311 MPa while maintaining satisfactory ductility (total elongation of 9.8%). Quantitative evaluation of strengthening mechanisms reveals the dislocation strengthening as the predominant contributor (accounts for about 55.9% of yield strength), followed by precipitation strengthening. Compared with 30MnB5 steel and existing literature‐reported systems, the 40Mn2CrNbV steel has excellent mechanical properties, mainly due to the synergistic interaction of Cr, Nb, and V microalloying elements. Specifically, the simultaneous incorporation of Nb and V facilitates the precipitation of nanoscale (Nb, V)C, induces grain refinement, and impedes dislocation motion through pinning effects. The average size of martensite block widths is 0.8 μm and the dislocation densities of 3.1 ± 0.4 × 10 15 m −2 for 40Mn2CrNbV hot‐stamped steel.