DQ51 is a high-strength, low-alloy ship plate grade compliant with global marine standards (e.g., EN 10225, GB/T 712), distinguished by its excellent low-temperature toughness and enhanced structural performance. A defining characteristic of DQ51 is its ability to maintain ductility and impact resistance at temperatures as low as -40°C, thanks to its refined microstructure and controlled chemical composition (including 0.16% max carbon, 1.60% max manganese, and alloying elements like niobium or vanadium for grain refinement). It also boasts a minimum yield strength of 345 MPa and tensile strength of 490-630 MPa, ensuring robust load-bearing capability in demanding conditions.
The main function of DQ51 is to provide reliable structural support in ships and offshore structures operating in cold marine environments, where low temperatures could cause brittle fracture in standard ship plates. Its advantages are centered on low-temperature performance: unlike AQ51, DQ51 passes strict impact tests at -40°C, making it ideal for cold regions. It also offers superior fatigue resistance, crucial for components subjected to repeated dynamic loads (such as hulls in rough seas). Additionally, DQ51 maintains good weldability—though it may require slight pre-heat treatment in cold weather, it still integrates easily into standard shipbuilding processes.
DQ51 is extensively used in the construction of ice-class ships, offshore supply vessels, and large cargo ships operating in polar or sub-polar regions (e.g., the Arctic or Antarctic shipping routes). Key applications include hull bottom plating, bow sections (exposed to ice impact), and load-bearing bulkheads that must withstand low temperatures and heavy loads. It is also a preferred material for offshore wind turbine foundations in cold coastal areas, as it resists both low temperatures and harsh seawater corrosion. Furthermore, DQ51 is used in naval vessels designed for cold-water operations, where structural integrity in extreme conditions is non-negotiable.
