EQ63 represents the pinnacle of high-strength ship plate grades, complying with the most stringent international marine standards for extreme cold and high-stress conditions. Its most notable feature is exceptional cryogenic toughness: it maintains excellent impact resistance at temperatures as low as -60°C, a critical requirement for polar operations. Chemically, it is alloyed with nickel (up to 0.50%) and niobium to enhance cryogenic performance, while retaining a minimum yield strength of 450 MPa and tensile strength of 570-720 MPa. Enhanced corrosion resistance, from controlled chromium content (up to 0.30%) and low sulfur/phosphorus levels, further suits it to harsh marine environments.
The primary role of EQ63 is to act as a safety-critical material in ships and offshore structures operating in the harshest conditions—polar regions, heavy ice, and extreme temperature fluctuations—where even minor material failure could be catastrophic. Its unmatched advantages include superior cryogenic resilience, outperforming AQ63 and DQ63 in -60°C tests. It also offers exceptional stress corrosion cracking resistance, vital for parts exposed to freezing saltwater and constant mechanical stress. While it requires specialized welding fillers, the welded joints maintain the same extreme-temperature performance as the base material, ensuring structural uniformity.
EQ63 is exclusively used in the most demanding marine applications. It is the material of choice for icebreakers, polar research vessels, and Arctic oil exploration ships, where its ice-impact resistance and cryogenic performance are non-negotiable. Key applications include ice-breaking bows, polar - zone hull plating, and critical load-bearing structures like keels and bulkheads. It is also used in offshore LNG terminals in cold regions, withstanding LNG storage temperatures while resisting seawater corrosion. Additionally, EQ63 serves in specialized naval vessels for Arctic operations, where its ability to endure extreme cold and ice damage is essential for mission success. Its premium performance justifies the higher cost in safety-critical, extreme-environment scenarios.
