Hot Stamping of Heavy-Gaged - Full Development and the Effect of Press Hardening Process on the Microstructure and Mechanical Properties of 22MnB5 + NbMo Alloyed

Abstract

For saving mass, to improve the payloads and the durability of commercial vehicles, it is necessary to increase the thickness range of PHS - Press Hardening Steel, replacing low strength steel grades on structural and saving parts. This work presents the industrial development of Heavy-Gaged PHS-Press hardening Steel (4-8mm) starting from the alloy design concept, especially adding niobium to promote a fine and homogeneous microstructure. The development included hot forming simulations, in order to achieve martensitic microstructure through the thickness, correlating with cooling rates and mechanical characteristics, after quenching, as well as welding qualification and fatigue evaluation. Furthermore, were presented the characterization of 22MnB5(Nb+Mo) steel after industrial hot stamping that were evaluated mechanical properties, using the Vickers 10Kgf and the relationship between the microstructure and the thermodynamic aspects.