Multiphase microstructure regulation and its influence on the mechanical properties of EH500-grade ultraheavy plate steel for marine engineering

With the increasing demand for large-scale, lightweight, and highly safe ocean transportation vessels and drilling equipment, as well as the growing need for environmentally friendly steels, the demand for high-strength, high-toughness, and weldable thick steel plates for ships and ocean engineering is becoming increasingly significant. However, as the strength and thickness of steel plates increase, the low-temperature toughness of the center of high-strength and extra-thick steel plates has become a significant challenge. Owing to low rolling reduction and central segregation in ultra-heavy plate steel, the poor low-temperature toughness of the central region poses a major challenge that limits the application of high-strength ultra-heavy steels. This work systematically investigated the effects of a two-step intercritical heat treatment on regulating the multiphase microstructure and properties of 100 mm EH500 marine engineering steel with severe central segregation. The results showed that after intercrit