Nippon Steel & Mitsubishi Shipbuilding received the world's first General Design Approval from ClassNK for low-pressure liquefied CO₂ tank technology. The approval validates post-weld heat treatment exemption based on Engineering Critical Assessment using Nippon Steel's developed KF460 steel. The breakthrough addresses manufacturing constraints where limited heat-treatment furnace capacity hindered large tank production. The technology enables larger, more economical CO₂ carriers supporting carbon capture transportation infrastructure. The KF460 steel features high strength, excellent low-temperature toughness, & economic viability through Thermo-Mechanical Control Process manufacturing. Both companies plan to commercialise the technology alongside supply-chain partners.