The microstructure and mechanical properties of low-carbon martensite steel with tensile strength of about 1000MPa

An ultra-high strength weldable steel with a tensile strength of about 1000MPa is developed.The steel has a chemical composition based on 0.12%-0.16% C-Mn-B and a microstructure comprising fine-grained martensite lath and a small fraction of predominantly auto-tempered martensite lath.The influence of chemical composition and heat-treatment on the microstructure and mechanical properties of the steel is investigated.