Investigation on Strengthening and Toughening of Developed Low‐Alloy Structural Steel

Q355 steel represents one of the highest‐volume production low‐alloy steels globally. The high‐Ti low‐Mn alloy design significantly enhances its cost‐effectiveness. This study investigates the microstructure and mechanical properties of a developed high‐Ti low‐Mn Q355 steel across two thickness specifications, with comparative analysis against conventional Q355B steel. Through elucidation of the strengthening and toughening contributions, the critical production requirement is identified: promoting TiC particle precipitation during rolling. This finding provides fundamental guidance for optimizing production processes and refining chemical compositions. Results demonstrate that under current processing conditions, 25 mm‐thick high‐Ti low‐Mn Q355 steel plate achieves all design objectives, satisfying Grade B and even Grade C requirements. The enhanced strength and superior impact toughness (at both 20 and 0 °C) primarily derive from grain refinement and TiC precipitation.