FH40 ship plate is a high-strength hull structural steel with a yield strength of ≥390MPa, designed for extreme marine environments. Its chemical composition is further optimized on the basis of FH36, and through microalloying and ultra-fine grain technology, it achieves a perfect combination of strength, toughness and corrosion resistance. The research and development of FH40 marks a breakthrough in ship materials to higher performance areas, especially for special ships such as icebreakers and polar research vessels.
Technical features and advantages
Ultra-high strength and lightweight: The yield strength of FH40 is about 24% higher than that of FH32, and the thickness of the plate can be reduced by 15%-20% under the same load conditions. For example, a 100,000-ton icebreaker uses FH40 instead of ordinary ship plates, which can reduce weight by about 1,200 tons and improve icebreaking capability and fuel efficiency.
Excellent low-temperature toughness: By controlling the purity (O≤0.003%, N≤0.008%) and grain size (ASTM grade 10 and above), the impact energy of FH40 at -40℃ is ≥47J, which meets the impact resistance requirements of polar ships when sailing in ice areas. The icebreakers on the Russian Arctic route use FH40 steel and successfully withstand the extreme low temperature environment of -50℃.
Fatigue resistance and welding performance: The fatigue limit of FH40 is 40% higher than that of ordinary ship plates, and the toughness of the welding heat affected zone (HAZ) is good. High-efficiency welding processes (such as submerged arc welding and gas shielded welding) can be used, and the welding efficiency is increased by more than 25%.
Typical application cases
Polar icebreaker: The world's largest nuclear-powered icebreaker "Arctic" uses FH40 steel to build the bow icebreaking area and key load-bearing structures. It can continuously break 2.8 meters thick ice and sail in the frozen waters of the Arctic.
Deep-sea drilling platform: used in the pile legs and jackets of deep-water semi-submersible drilling platforms, and withstands deep-sea high pressure, low temperature and ocean current impact. For example, the pile legs of an ultra-deepwater drilling platform in the South China Sea are made of FH40 steel, with a designed water depth of 3,000 meters.
Luxury cruise ship: used for high-strength structural parts of cruise ships, such as bow anti-collision bulkheads and helicopter decks, which reduce weight while ensuring safety, and improve the comfort and economy of cruise ships.
Production process and standards
The production of FH40 ship plates requires the use of advanced TMCP (thermomechanical control process) or quenching + tempering (Q+T) processes to ensure that the steel structure is uniform and fine. Internationally, the main standards of classification societies such as ABS, DNV, and LR are implemented, while China adopts the GB/T 712-2011 "Structural Steel for Ships and Marine Engineering" standard, which strictly stipulates the chemical composition, mechanical properties and inspection methods.
