Resistance of Quench and Partitioned Steels Against Hydrogen Embrittlement

Abstract Multiphase ultra-high strength steels (UHSS) containing retained austenite (RA) appear to be among the most interesting for automotive industry. Developments in last decades have allowed obtaining a very good combination of mechanical and ductility. Quenching partitioning (Q&P) been proposed as third-generation UHSS, reaching ultimate tensile up 1300 MPa along with excellent fracture elongations more than 15%. However, use Q&P is mainly limited by their susceptibility hydrogen embrittlement (HE). The present work investigates influence heat treatment parameters on properties HE resistivity 20Mn-Si wire rod steel. was measured using incremental step load testing situ electrochemical charging according ASTM F1624-12 standard. A comprehensive microstructure characterization performed examine volume fraction, nucleation sites morphologies RA. Although were similar after treatment, an increase time revealed significant threshold stress 200 MPa.