EQ51 is a top-tier high-strength ship plate grade, meeting the most stringent international marine standards (e.g., EN 10225, ASTM A131) for extreme environmental conditions. Its standout features are exceptional low-temperature toughness and ultra-high structural reliability: it retains excellent impact resistance at temperatures as low as -60°C, a critical attribute for ships in the harshest cold regions. Chemically, EQ51 is alloyed with elements like nickel, niobium, and titanium to enhance its cryogenic performance, while maintaining a minimum yield strength of 345 MPa and tensile strength of 490-630 MPa—matching the strength of AQ51 and DQ51 but with far superior low-temperature capabilities. It also has enhanced corrosion resistance, thanks to a higher chromium content (up to 0.30%) and controlled sulfur and phosphorus levels, reducing the risk of pitting in saltwater.
The primary role of EQ51 is to serve as a safety-critical material in ships and offshore structures operating in extreme cold, high-stress, or high-corrosion environments, where even minor material failure could lead to catastrophic consequences. Its advantages include unmatched cryogenic toughness—passing rigorous impact tests at -60°C—and excellent resistance to stress corrosion cracking, a common issue in cold, salty environments. It also offers superior weld integrity: when welded with appropriate techniques, EQ51 maintains its low-temperature performance in the heat-affected zone, eliminating weak points in the structure.
EQ51 is exclusively used in the most demanding marine applications, such as icebreakers, polar research vessels, and offshore oil platforms in Arctic regions. Key applications include the ship’s ice-breaking bow, hull plating exposed to continuous ice impact, and critical load-bearing structures that must function reliably at -60°C. It is also used in specialized naval vessels designed for Arctic operations, where structural resilience in extreme cold is a strategic requirement. Additionally, EQ51 is employed in the construction of liquefied natural gas (LNG) carriers, as it can withstand the low temperatures of LNG storage while resisting seawater corrosion.
